UNIVERSITY OF CALIFORNIA 
 LOS ANGELES
 
 CHARLES DARWIN.
 
 THE DESCENT OF MAN 
 
 And Selection in Relation to Sex 
 By CHARLES DARWIN, M.A..F.R.S. 
 
 Author of "THE ORIGIN OF SPECIES," etc., etc.; 
 
 Reprinted from the Second English Edition, 
 Revised and Augmented 
 
 ILLUSTRATED 
 
 A. L. BURT COMPANY, j j . j j* 
 
 * * * ji PUBLISHERS, NEW YORK
 
 QH 
 
 |SW- 
 PREFACE TO THE SECOND EDITION. 
 
 DURING the successive reprints of the first edition of 
 this work, published in 1871, I was able to introduce sev- 
 eral important corrections; and now that more time has 
 elapsed I have endeavored to profit by the fiery ordeal 
 through which the book has passed, and have taken ad- 
 vantage of all the criticisms which seem to me sound. I 
 am also greatly indebted to a large number of correspond- 
 ents for the communication of a surprising number of new 
 facts and remarks. These have been so numerous that I 
 have been able to use only the more important ones; and 
 of these, as well as of the more important corrections, I 
 will append a list. Some new illustrations have been in- 
 troduced and four of the old drawings have been replaced 
 by better ones, done from life by Mr. T. W. Wood. I 
 must especially call attention to some observations which I 
 owe to the kindness of Prof. Huxley (given as a supple- 
 ment at the end of Part I), on the nature of the differences 
 between the brains of man and tile higher apes. I have 
 been particularly glad to give these observations, because 
 during the last few years several memoirs on the subject 
 have appeared on the Continent and their importance has 
 been, in some cases, greatly exaggerated by popular writers. 
 
 I may take this opportunity of remarking that my critics 
 frequently assume that I attribute all changes of corporeal 
 structure and mental power exclusively to the natural se- 
 lection of such variations as are often called spontaneous; 
 whereas, even in the first edition of the " Origin of 
 Species," I distinctly stated that great weight must be at-
 
 iv PREFACE. 
 
 tributed to the inherited effects of use and disuse, with re- 
 spect both to the body and mind. I also attributed some 
 amount of modification to the direct and prolonged action 
 of changed conditions of life. Some allowance, too, must 
 be made for occasional reversions of structure; nor must we 
 forget what I have called " correlated " growth, meaning 
 thereby that various parts of the organization are in some 
 unknown manner so connected, that when one part varies 
 so do others; and if variations in the one are accumulated 
 by selection other parts will be modified. Again, it has 
 been said by several critics that when I found that many 
 details of structure in man could not be explained through 
 natural selection, I invented sexual selection; I gave, how- 
 ever, a tolerably clear sketch of this principle in the first 
 edition of the " Origin of Species/' and I there stated that 
 it was applicable to man. This subject of sexual selection 
 has been treated at full length in the present work, simply 
 because an opportunity was here first afforded me. I have 
 been struck with the likeness of many of the half-favorable 
 criticisms on sexual selection, with those which appeared 
 at first on natural selection; such as, that it would explain 
 some few details, but certainly was not applicable to the 
 extent to which I have employed it. My conviction of the 
 power of sexual selection remains unshaken ; but it is 
 probable, or almost certain, that several of my conclusions 
 will hereafter be found 'erroneous; this can hardly fail to 
 be the case in the first treatment of a subject. When 
 naturalists have become familiar with the idea of sexual 
 selection, it will, as I believe, be much more largely ac- 
 cepted; and it has already been fully and favorably re- 
 ceived by several capable judges. 
 
 DOWN, BECXENHAM, KENT, September, 1874
 
 CONTENTS. 
 
 PAGE. 
 
 INTRODUCTION 1 
 
 PART I. 
 
 THE DESCENT OR ORIGIN OF MAE". 
 
 CHAPTER L 
 The Evidence of the Descent of Man from Some Lower Form. . 5 
 
 CHAPTER II. 
 On the Manner of Development of Man from Some Lower Form 29 
 
 CHAPTER III. 
 
 Comparison of the Mental Powers of Man and the Lower 
 
 Animals 73 
 
 CHAPTER IV. 
 
 Comparison of the Mental Powers of Man and the Lower 
 
 Animals continued 110 
 
 CHAPTER V. 
 
 On the Development of the Intellectual and Moral Faculties 
 
 During Primeval and Civilized Times 144 
 
 CHAPTER VI. 
 On the Affinities and Genealogy of Man 166 
 
 CHAPTER VIL 
 On the Races of Man. . . .189
 
 fi CONTENTS. 
 
 PART II. 
 
 SEXUAL SELECTION. 
 
 CHAPTER VHL 
 Principles of Sexual Selection 234 
 
 CHAPTER IX. 
 
 Secondary Sexual Characters in the Lower Classes of the Ani- 
 mal Kingdom 294 
 
 CHAPTER X. 
 Secondary Sexual Characters of Insects 811 
 
 CHAPTER XI. 
 Insects, continued Order Lepidoptera. Butterflies and Moths. 348 
 
 CHAPTER XII. 
 
 Secondary Sexual Characters of Fishes, Amphibians, and 
 
 Reptiles 375 
 
 CHAPTER XHL 
 Secondary Sexual Characters of Birds 407 
 
 CHAPTER XIV. 
 Birds continued 459 
 
 CHAPTER XV. 
 Birds continued 505 
 
 CHAPTER XVI. 
 Birds concluded 628 
 
 CHAPTER XVTI. 
 Secondary Sexual Characters of Mammals 570
 
 CONTENTS. Tii 
 
 CHAPTER XVIII. 
 
 PAOI. 
 Secondary Sexual Characters of Mammals continued 600 
 
 PART III. 
 
 SEXUAL SELECTION IN KELATION TO MAN, AND CONCLUSION. 
 
 CHAPTER XIX. 
 Secondary Sexual Characters of Man , 684 
 
 CHAPTER XX. 
 Secondary Sexual Characters of Man continued. 668 
 
 CHAPTER YXT. 
 General Summary and Conclusion 693 
 
 SUPPLEMENTAL NOTE 709 
 
 INDEX , 715
 
 THE DESCENT OF MAN; 
 
 AND 
 
 SELECTION IN RELATION TO SEX. 
 
 INTRODUCTION. 
 
 THE nature of the following work will be best understood 
 by a brief account of how it came to be written. During 
 many years I collected notes on the origin or descent of 
 man, without any intention of publishing on the subject, 
 but rather with the determination not to publish, as I 
 thought that I should thus only add to the prejudices 
 against my views. It seemed to me sufficient to indicate, 
 in the first edition of my " Origin of Species," that by this 
 work " light would be thrown on the origin of man and his 
 history;" and this implies that man must be included with 
 other organic beings in any general conclusion respecting 
 his manner of appearance on this earth. Now the case 
 wears a wholly different aspect. When a naturalist like 
 Carl Vogt ventures to say in his address as President of the 
 National Institution of Geneva (1869), " personne, en 
 Europe au moins, n'ose plus soutenir la creation independ- 
 ante et de toutes pieces, des especes," it is manifest that at 
 least a large number of naturalists must admit that species 
 are the modified descendants of other species; and this es- 
 pecially holds good with the younger and rising naturalists. 
 The greater number accept the agency of natural selection; 
 though some urge, whether with justice the future must 
 decide, that I have greatly overrated its importance. Of 
 the older and honored chiefs in natural science, many un- 
 fortunately are still opposed to evolution in every form. 
 
 In consequence of the views now adopted by most natu- 
 ralists, and which will ultimately, as in every other case, be
 
 2 THE DESCENT OF MAN. 
 
 followed by others who are not scientific, I have been led to 
 put together my notes, SQ as to see how far the general con- 
 clusions arrived at in my former works were applicable to 
 man. This seemed all the more desirable, as I had never 
 deliberately applied these views to a species taken singly. 
 When we confine our attention to any one form, we are de- 
 prived of the weighty arguments derived from the nature 
 of the affinities which connect together whole groups of 
 organisms their geographical distribution in past and pres- 
 ent times, and their geological succession. The homologi- 
 cal structure, embryo-logical development, and rudimentary 
 organs of a species remain to be considered, whether it be 
 man or any other animal, to which our attention may be 
 directed; but these great classes of facts afford, as it ap- 
 pears to me, ample and conclusive evidence in favor of the 
 principle of gradual evolution. The strong support derived 
 from the other arguments should, however, always be kept 
 ' sfore the mind. 
 
 The sole object of this work is to consider, firstly, 
 whether man, like every other species, is descended from 
 ^some pre-existing form; secondly, the manner of his devel- 
 opment; and thirdly, the value of the differences between 
 the so-called races of man. As I shall confine myself to 
 these points, it will not be necessary to describe in detail 
 the differences between the several races an enormous sub- 
 ject which has been fully discussed in many valuable works. 
 The high antiquity of man has recently been demonstrated 
 by the labors of a host of eminent men, beginning with M. 
 Boucher de Perthes; and this is the indispensable basis for 
 understanding his origin. I shall, therefore, take this 
 conclusion for granted, and may refer my readers to the 
 admirable treatises of Sir Charles Lyell, Sir John Lubbock, 
 and others. Nor shall I have occasion to do more than to 
 allude to the amount of difference between man and the 
 anthropomorphous apes; for Prof. Huxley, in the opinion 
 of most competent judges, has conclusively shown that in 
 every visible character man differs less from the higher 
 apes than these do from the lower members of the same 
 order of Primates. 
 
 This work contains hardlv any original facts in regard 
 to man; but as the conclusions at which I arrived, after 
 drawing up a rough draft, appeared to me interesting, I 
 thought that they might interest others. It has often and
 
 INTRODUCTION. 3 
 
 confidently been asserted that man's origin can never be 
 known: but ignorance more frequently begets confidence 
 than does knowledge: it is those who know little, and not 
 those who know much, who so positively assert that this or 
 that problem will never be solved by science. The^con- 
 clusion thatjnan jsjhe _co-iLescendant -with other species of 
 some ancient, lower, and extinct form, is not in any degree 
 new. Lamarck long ago came to this conclusion, which 
 has lately been maintained.. by several eminent naturalists 
 and philosophers; for instance, by Wallace, Huxley, Lyell, 
 Vogt, LubboCk," Buchner, Kolle, etc.,* and especially by 
 Hackel. This last naturalist, besides his great work, 
 "Generelle Morphologic* (1866), has recently (1868, 
 with a second edition in 1870), published his "NatUrliche 
 Schopfungsgesehichte," in which he fully discusses the 
 genealogy of man. If this work had appeared before my 
 essay had been written, I should probably never have com- 
 pleted it. Almost all the conclusions at which I have 
 arrived I find confirmed by this naturalist, whose knowl- 
 edge on many points is much fuller than mine. Wherever 
 I have added any fact or view from Prof. HackeFs writ- 
 ings, I give his authority in the text; other statements I 
 leave as they originally stood in my manuscript, occasion- 
 ally giving in the footnotes references to his works, as a 
 confirmation of the more doubtful or interesting points. 
 
 During many years it has seemed to me highly probable 
 that sexual selection has played an important part in 
 differentiating the races of man; but in my "Origin 
 of Species" (first edition) I contented myself by 
 merely alluding to this belief. When I came to apply this 
 view to man, I found it indispensable to treat the whole 
 
 *As the works of the first-named authors are so well known, I 
 need not give the titles ; but as those of the latter are less well 
 known in England, I will give them : " Sechs Vorlesungen iiber die 
 Darwin'sche Theorie," zweite Auflage, 1868, von Dr. L. Buchner ; 
 translated into French under the title " Conferences sur la Theorie 
 Darwinienne," 1869. " Der Mensch, im Lichte der Darwin'sche 
 Lehre," 1865, von Dr. F. Rolle. I will not attempt to give references 
 to all the authors who have taken the same side of the question. 
 Thus G. Canestrini has published (" Annuario della Soc. d. Nat.," 
 Modena, 1867, p. 81), a very curious paper on rudimentary characters, 
 as bearing on the origin of man. Another work has (1869) been 
 published by Dr. Francesco Barrago, bearing in Italian the title 
 of " Man, made in the image of God. was also made in tke image of 
 the ape."
 
 4 THE DESCENT OF MAN. 
 
 subject in full detail.* Consequently, the second part of 
 the present work, treating of sexual selection, has extended 
 to an inordinate length, compared with the first part; but 
 this could not be avoided. 
 
 I had intended adding to the present volume an essay on 
 the expression of the various emotions by man and the 
 lower animals. My attention was called to this subject 
 many years ago by Sir Charles Bell's admirable work. 
 This illustrious anatomist maintains that man is endowed 
 with certain muscles solely for the sake of expressing his 
 emotions. As this view is obviously opposed to the belief 
 that man is descended from some other and lower form, it 
 was necessary for me to consider it. I likewise wished to 
 ascertain how far the emotions are expressed in the same 
 manner by the different races of man. But owing to the 
 length of the present work, I have thought it better to re- 
 serve my essay for separate publication. 
 
 * Prof. Hackel was the only author, who, at the time when this 
 work first appeared, had discussed the subject of sexual selection, 
 and had seen its full importance, since the publication of the 
 "Origin;" and this he did in a very able manner in his various 
 works.
 
 PART I. 
 
 THE DESCENT OR ORIGIN OF MAN. 
 
 CHAPTER I. 
 
 THE EVIDENCE OF THE DESCENT OP MAN FKOM SOME 
 LOWER POEM. 
 
 Nature of the evidence bearing 1 on the origin of man Homologous 
 structures in man and the lower animals Miscellaneous points 
 of correspondence Development Rudimentary structures, 
 muscles, sense-organs, hair, bones, reproductive organs, etc. 
 The bearing of these three great classes of facts on the origin of 
 man. 
 
 HE who wishes to decide whether man is the modified 
 descendant of some pre-existing form, would probably first 
 inquire whether man varies, however slightly, in bodily 
 structure and in mental faculties; and if so, whether the 
 variations are transmitted to his offspring in accordance 
 with the laws which prevail with the lower animals. Again, 
 are the variations the result, as far as our ignorance permits 
 us to judge, of the same general causes, and are they 
 governed by the same general laws, as in the case of other 
 organisms; for instance, by correlation, the inherited effects 
 of use and disuse, etc. ? Is man subject to similar malcon- 
 f prmations, the result of arrested development, of reduplica- 
 tion of parts, etc., and does he display in any of his anoma- 
 lies reversion to some former and ancient type of structure? 
 It might also naturally be inquired whether man, like so 
 many other animals, has given rise to varieties and sub- 
 races, differing but slightly from each other, or to races 
 differing so much that they must be classed as doubtful 
 Bpecies? How are such races distributed over the world; 
 and how, when crossed, do they react on each other in the 
 first and succeeding generations? And so with many other 
 points.
 
 6 THE DESCENT OF MAN. 
 
 The inquirer would next come to the important point, 
 whether man tends to increase at so rapid a rate, as to lead 
 to occasional severe struggles for existence ; and conse- 
 quently to beneficial variations, whether in body or mind, 
 being preserved, and injurious ones eliminated. Do the 
 races or species of men, whichever term may be applied, 
 encroach on and replace one another, so that some finally 
 become extinct ? We shall see that all these questions, as 
 indeed is obvious in respect to most of them, must be an- 
 swered in the affirmative, in the same manner as with the 
 lower animals. But the several considerations just referred 
 to may be conveniently deferred for a time : and we will 
 first see how far the bodily structure of man shows traces, 
 more or less plain, of his descent from some lower form. 
 In succeeding chapters the mental poAvers of man, in com- 
 parison with those of the lower animals, will be considered. 
 
 The Bodily Structure of Man. It is notorious that man 
 is constructed on the same general type or model as other 
 mammals. All the bones in his skeleton can be compared 
 with corresponding bones in a monkey, bat, or seal. So it 
 is with his muscles, nerves, blood-vessels, and internal vis- 
 cera. The brain, the most important of all the organs, 
 follows the same law, as shown by Huxley and other anato- 
 mists. Bischoff,* who is a hostile witness, admits that every 
 chief fissure and fold in the brain of man has its analogy 
 in that of the orang ; but he adds that at no period of de- 
 velopment do their brains perfectly agree ; nor could per- 
 fect agreement be expected, for otherwise their mental pow- 
 ers would have been the same. Vulpianf remarks : " Les 
 differences reelles qui existent entre Fencephale de 1'homme 
 et celui des singes superieurs, sont bein minimes. II ne 
 faut pas se faire d'illusions a cet egard. L'homme est bein 
 plus pres des singes anthropomorphes par les caracteres 
 anatomiques de son cerveau que ceux-ci ne le sont non seul- 
 ement des autres mammif res, mais me'me de certains quad- 
 rumanes, des guenons et des macaques." But it would be 
 
 * " Grosshirnwindungen des Menschen," -1868, s. 96. The con-- 
 elusions of this author, as well as those of Gratiolet and Aeby, con- 
 cerning the brain, will be discussed by Prof. Huxley in the Appendix 
 alluded to in the Preface to this edition. 
 
 f'Lec. sur la Phys.," 1866, p. 890, as quoted by M. Dally, 
 " L'Ordre des Primates et le Transformisme," 1868, p. 29.
 
 HOMOLOGICAL STRUCTURES. 7 
 
 superfluous here to give further details on the correspond- 
 ence between man and the higher mammels in the structure 
 of the brain and all other parts of the body. 
 
 It may, however, be worth while to specify a few points, 
 not directly or obviously connected with structure, by which 
 this correspondence or relationship is well shown. 
 
 Man is liable to receive from the lower animals, and 
 to communicate to them, certain diseases, as hydrophobia, 
 variola, the glanders, syphilis, cholera, herpes, etc. ;* and 
 this fact proves the close similarity! of their tissues and 
 blood, both in minute structure and composition, far more 
 plainly than does their comparison under the best micro- 
 scope, or by the aid of the best chemical analysis. Mon- 
 keys are liable to many of the same non-contagious diseases 
 as we are; thus Eengger, J who carefully observed for a long 
 time the Cebus Azarce in its native land, found it liable to 
 catarrh, with the usual symptoms, and which, when often 
 recurrent, led to consumption. These monkeys suffered 
 also from apoplexy, inflammation of the bowels, and cata- 
 ract in the eye. The younger ones when shedding their 
 milk-teeth often died from fever. Medicines produced the 
 same effect on them as on us. Many kinds of monkeys 
 have a strong taste for tea, coffee, and spirituous liquors : 
 they will also, as I have myself seen, smoke tobacco with 
 pleasure. Brehm asserts that the natives of north-eastern 
 Africa catch the wild baboons by exposing vessels with 
 strong beer, by which they are made drunk. He has seen 
 some of these animals, which he kept in confinement, in 
 
 * Dr. W. Lauder Lindsay has treated this subject at some length 
 in the "Journal of Mental'Science," July, 1871; and in the "Edin- 
 burgh Veterinary Review," July, 1858. 
 
 f A Reviewer has criticised ("British Quarterly Review," Oct. 1, 
 1871, p. 472) what I have here said with much severity and contempt ; 
 but as I do not use the term identity, I cannot see that I am greatly 
 in error. There appears to me a strong analogy between the same 
 infection or contagion producing the same result, or one closely simi- 
 lar, in two distinct animals, Lfld the testing of two distinct fluids by 
 the same chemical reagent. 
 
 J " Naturgeschichte der Saugethiere von Paraguay," 1830, s. 50. 
 
 The same tastes are common to some animals much lower in the 
 scale. Mr. A. Nichols informs me that he kept in Queensland, in 
 Australia, three individuals of the Phaseolarctus cinereus ; and that, 
 without having been taught in any way, they acquired a strong taste 
 for rum and smoking tobacco.
 
 8 THE DESCENT OF MAN. 
 
 this state; and ha gives a laughable account of their behav- 
 ior and strange grimaces.' 1 On the following morning they 
 were very cross and dismal; they held their aching heads 
 with both hands, and wore a most pitiable expression; when 
 beer or wine was offered them, they turned away with dis- 
 gust, but relished the juice of lemons.* An American 
 monkey, an Ateles, after getting drunk on brandy, would 
 never touch it again, and thus was wiser than many men. 
 These trifling facts prove how similar the nerves of taste 
 must oe in monkeys and man, and how similarly their whole 
 nervous system is affected. 
 
 Man is infested with internal parasites, sometimes causing 
 fatal effects; and is plagued by external parasites, all of 
 which belong to the same genera or families as those infest- 
 ing other mammals, and in the case of scabies to the same 
 species, f Man is subject, like other mammals, birds, and 
 even insects, J to that mysterious law, which causes certain 
 normal processes, such as gestation, as well as the matura- 
 tion and duration of various diseases, to follow lunar periods. 
 His wounds are repaired by the same process of healing; 
 and the stumps left after the amputation of his limbs, es- 
 pecially during an early embryonic period, occasionally 
 possess some power of regeneration, as in the lowest 
 animals. 
 
 The whole process of that most important function, the 
 reproduction of the species, is strikingly the same in all 
 mammals, from the first act of courtship by the male, | to 
 
 *Brehm, " Thierleben," B. i, 1864, 8.75, 86. On the Ateles, s. 
 105. For other analogous statements, see s. 25, 107. 
 
 f Dr. W. Lauder Lindsay, " Edinburgh Veterinary Review," July, 
 1858, p. 13. 
 
 \ With respect to insects see Dr. Laycock " On a General Law of 
 Vital Periodicity," "British Association," 1842. Dr. Macculloch, 
 " Silliman's North American Journal of Science," vol. xvii, p. 305, 
 has seen a dog suffering from tertian ague. Hereafter I shall return 
 to this subject. 
 
 1 have given the evidence on this head in my "Variation of 
 Animals and Plants under Domestication," vol. ii, p. 15, aud more 
 could be added. 
 
 J Mares e diversis generibus Quadrumanorum sine dubio dignos- 
 cunt feminas humanas a maribus. Primurn, credo, odoratu, postea 
 aspectu. Mr. Youatt, qui diu in Hortis Zoologicis (Bestiariis) medi- 
 cus animalium erat, vir in rebus observandis cautus et sagax, hoc 
 mihi certissime probavit, et curatores ejusdeui loci et alii e ministris 
 confirm* verunt. Sir Andrew Smith et Brehm notabant idem in Cyuo
 
 HOMOLOGICAL STEVCTVUEh. 9 
 
 the birth and nurturing of the young. Monkeys are born 
 in almost as helpless a condition as our own infants; and in 
 certain genera the young differ fully as much in appearance 
 from the adults, as do our children from their full-grown 
 parents.* It has been urged by some writers, as an import- 
 ant distinction, that with man the young arrive at maturity 
 at a much later age than with any. other animal: but if we 
 look to the races of mankind which inhabit tropical coun- 
 tries the difference is not great, for the orang is believed 
 not to be adult till the age of from ten to fifteen years, f 
 Man differs from woman in size, bodily strength, hairiness, 
 etc. , as well as in mind, in the same manner as do the two 
 sexes of many mammals. So that the correspondence in 
 general structure, in the minute structure of the tissues, in 
 chemical composition and in constitution, between man and 
 the higher animals, especially the anthropomorphous apes, 
 is extremely close. 
 
 Embryonic Development. Man is developed from an 
 ovule, about the 125th of an inch in diameter, which differs 
 in no respect from the ovules of other animals. The 
 embryo itself at a very early period can hardly be distin- 
 guished from that of other members of the vertebrate king- 
 dom. At this period the arteries run in arch-like branches, 
 as if to carry the blood to branchiae which are not present 
 in the higher vertebrata, though the slits on the sides of the 
 neck still remain (/, g, fig. 1), marking their former posi- 
 tion. At a somewhat later period, when the extremities 
 are developed, "the feet of lizards and mammals," as the 
 illustrious Von Baer remarks, "the wings and feet of birds, 
 no less than the hands and feet of man, all arise from 
 the same fundamental form/' It is, says Prof. Huxley, J 
 
 ceplialo. Illustrissimus Cuvier etiam narrat multa de Me re, qua" 
 ut opinor, nihil turpius potest indicari inter oninia borninibus et 
 Quadrumanis communia. Narrat enim Cynocepbaluin quendam in 
 f urorem incidere aspectu feuiinarum aliquaruin, sed nequaquam ac- 
 cendi tanto furore ab omnibus. Semper eligebat juniores, et dignos- 
 cebat in turba, et advocabat voce gestuque. 
 
 *Tbis remark is made with respect to Cynocephalus and tbe 
 antbropomorpbous apes by Geoffrey Saint-Hilaire and F. Cuvier, 
 " Hist. Nat. des Mammiferes," torn, i, 1824. 
 
 f Huxley, " Man's Place in Nature." 1863, p. 34. 
 
 J ibid., p. 67.
 
 10 THE DESCENT OF MAN. 
 
 " quite in the later stages of development that the young 
 human being presents marked differences from the young 
 ape, while the latter departs as much from the dog in its 
 developments as the man does. Startling as this last asser- 
 tion may appear to be, it is demonstrably true." 
 
 As some of my readers may never have seen a drawing of 
 an embryo, I have given one of man and another of a dog, 
 at about the same early stage of development, carefully 
 copied from two works of undoubted accuracy,* 
 
 After the foregoing statements made by such high 
 authorities, it would be superfluous on my part to give a 
 number of borrowed details, showing that the embryo of 
 man closely resembles that of other mammals. It may, 
 however, be added, that the human embryo likewise resem- 
 bles certain low forms when adult in various points of 
 structure. For instance, the heart at first exists as a simple 
 pulsating vessel ; the excreta are voided through a cloacal 
 passage ; and the os coccyx projects like a true tail, " ex- 
 tending considerably beyond the rudimentary legs."f In 
 the embryos of all air-breathing vertebrates, certain glands, 
 called the corpora "Wolffiana, correspond with, and act 
 like the kidneys of mature fishes. J Even at a later 
 embryonic period, some striking resemblances between 
 man and the lower animals may be observed. BischofE 
 says that "the convolutions of the brain in a human fo3tus 
 at the end of the seventh month reach about the same 
 stage of development as in a baboon when adult. " 
 The great toe, as Prof. Owen remarks, | " which forms 
 the fulcrum when standing or walking, is perhaps 
 
 *The human embryo (upper fig.) is from Ecker, " Icones Phys.," 
 1851-1859, tab. xxx, fig. 2. This embryo was ten lines in length, so 
 that the drawing is much magnified. The embryo of the dog is from 
 Bischoff, " Entwicklungsgeschichte des Hunde-Eies," 1845, tab. xi, 
 fig. 42 B. This drawing is five times magnified, the embryo being 
 twenty-five days old. The internal viscer: have been omitted, and 
 the uterine appendages in both drawings removed. I was directed 
 to these figures by Prof. Huxley, from whose work, " Man's Place in 
 Nature," the idea of giving them was taken. Hackel has also given 
 analogous drawings in his " Scho'pfungsgeschichte." 
 
 fProf. Wyman in " Proc. of American Acad. of Sciences," vol. iv, 
 I860, p. 17. 
 
 JO wen, "Anatomy of Vertebrates," vol. i, p. 583. 
 
 "Die Qrosshirnwindungen des Menschen." 1868, s. 95. 
 
 U "Anatomy of Vertebrates." vpl. ii, p. 553.
 
 HOMOLOGICAL STRUCTURES. 
 
 11 
 
 Jiff. 1. Upper figure human embryo, from Ecker. Lower figure that of a dog, 
 from BischofE. 
 
 a. Fore-brain, cerebral hemispheres, 
 etc. 
 
 b. Mid-brain, corpora quadrigemina. 
 
 c. Hind-brain, cerebellum, medulla 
 oblongata, 
 
 d. Eye. 
 . Ear. 
 
 f. First visceral arch. 
 ff. Second visceral arch. 
 H. Vertebral columns and muscles 
 in process of development. 
 
 . L. Tail or os coccyx.
 
 12 THE DESCENT OF MAN. 
 
 the most characteristic peculiarity in the human struct, 
 ure;" but in an embryo, about an inch in length, Prof. 
 Wyman* found "that the great toe was shorter than the 
 others; and, instead of being parallel to them, projected at 
 an angle from the side of the foot, thus corresponding with 
 the permanent condition of this part in the quadrumana." 
 I will conclude with a quotation from Huxley, f who after 
 asking, does man originate in a different way from a dog, 
 bird, frog, or fish? says, "the reply is not doubtful for a 
 moment; without question, the mode of origin, and the 
 early stages of the development of man, are identical with 
 those of the animals immediately below him in the scale: 
 without a doubt in these respects he is far nearer to apes 
 than the apes are to the dog." 
 
 Rudiments. This subject, though not intrinsically more 
 important than the two last, will for several reasons be 
 treated here more fully. J Not one of the higher animals 
 can be named which does not bear some part in a rudi- 
 mentary condition; and man forms no exception to the 
 rule. Rudimentary organs must be distinguished from 
 those that are nascent; though in some cases the distinction 
 is not eas} r . The former are either absolutely useless, such 
 as the mammae of male quadrupeds, or the incisor teeth of 
 ruminants, which never cut through the gums; or they are 
 of such slight service to their present possessors, that we 
 can hardly suppose that they were developed under the 
 conditions which now exist. Organs in this latter state are not 
 strictly rudimentary, but they are tending in this direction. 
 Nascent organs, on the other hand, though not fully devel- 
 oped, are of high service to their possessors, and are capa- 
 ble of further development. Rudimentary organs are 
 eminently variable; and this is partly intelligible, as they 
 are useless, or nearly useless, and consequently are no 
 
 * " Proc. Soc. Nat. Hist.," Boston 1863, vol. ix, p. 185. 
 
 f "Man's Place in Nature," p. 65. 
 
 I had written a rough copy of this chapter before reading a valu- 
 able paper, " Caratteri rudimentali in ordine all" origine dell' uomo" 
 (" Annuario della Soc. d. Nat.," Modena, 1867, p. 81), by G. Canes- 
 trini, to which paper I am considerably indebted. Hackel has given 
 admirable discussions on this whole subject, under the title of Dys- 
 teleology, in his " Generelle Morphologic" and " Scho'pf ungsge- 
 schichte."
 
 RUDIMENTS. 13 
 
 longer subjected to natural selection. They often become 
 wholly suppressed. When this occurs, they are neverthe- 
 less liable to occasional reappearance through reversion a 
 circumstance well worthy of attention. 
 
 The chief agents in causing organs to become rudiment- 
 ary seem to have been disuse at that period of life when 
 the organ is chiefly used (and this is generally during matu- 
 rity), and also inheritance at a corresponding period of life. 
 The term "disuse" does not relate merely to the lessened 
 action of muscles, but includes a diminished flow of blood 
 to a part or organ, from being subjected to fewer alterna- 
 tions of pressure, or from becoming in any way less habitu- 
 ally active. Rudiments, however, may occur in one sex 
 of those parts which are normally present in the other sex; 
 and such rudiments, as we shall hereafter see, have often 
 originated in a way distinct from those here referred to. 
 In some cases, organs have been reduced by means of nat- 
 ural selection, from having become injurious to the species 
 under changed habits of life. The process of reduction is 
 probably often aided through the two principles of com- 
 pensation and economy of growth; but the later stages of 
 reduction, after disuse has done all that can fairly be at- 
 tributed to it, and when the saving to be effected by the 
 economy of growth would be very small,* are difficult to 
 understand. The final and complete suppression of a part, 
 already useless and much reduced in size, in which case 
 neither compensation nor economy come into play, is 
 perhaps intelligible by the aid of the hypothesis of pangene^ 
 sis. But as the whole subject of rudimentary organs has 
 been discussed and illustrated in my former works, f I need 
 here say no more on this head. 
 
 Eudiments of various muscles have been observed in 
 many parts of the human body ;| and not a few muscles, 
 
 * Some good criticisms on this subject have been given by Messrs. 
 Murie and Mivart, in "Transact. Zoolog. Soc.," 1869, vol. vii, p. 92. 
 
 f " Variation of Animals and Plants under Domestication," vol. ii, 
 pp. 317 and 397. See also "Origin of Species." 
 
 JFor instance M. Richard (" Annales des Sciences Nat., 3d series, 
 Zoolog., 1852, torn, xviii, p. 13) describes and figures rudiments of 
 what he calls the " muscle pedieux de la main," which he says is 
 sometimes " infiniment petit." Another muscle, called " le tibial 
 posterieur," is generally quite absent in the hand, but appears from 
 time to time in a more or less rudimentary condition.
 
 14 THE DESCENT OF MAN, 
 
 which are regularly present in some of the lower animals, 
 can occasionally be detectedjn man in a greatly reduced con- 
 dition. Every one must have noticed the power which many 
 animals, especially horses, possess of moving or twitching 
 their skin ; and this is effected by the panniculus carnosus. 
 Remnants of this muscle in an efficient state are found in 
 various parts of pur bodies ; for instance, the muscle on the 
 forehead, by which the eyebrows are raised. The platysma 
 myoides, which is well developed on the neck, belongs to 
 this system. Prof. Turner, of Edinburgh, has occa- 
 sionally detected, as he informs me, muscular fasciculi in 
 five different situations, namely in the axillae, near the 
 scapulae, etc., all of which must be referred to the system 
 of the panniculus. He has also shown* that the musculus 
 sternalis or sternalis brutorum, which is not an extension 
 of the rectus abdominalis, but is closely allied to the pan- 
 niculus, occurred in the proportion of about three per cent. 
 in upwards of 600 bodies ; he adds, that this muscle affords 
 " an excellent illustration of the statement that occasional 
 and rudimentary structures are especially liable to variation 
 in arrangement. " 
 
 Some few persons have the power of contracting the 
 superficial, muscles on their scalps ; and these muscles are 
 in a variable and partially rudimentary condition. M. A. 
 de Candolle has communicated to me a curious instance of 
 the long-continued persistence or inheritance of this power, 
 as well as of its unusual development. He knows a family, 
 in which one member, the present head of the family, 
 could, when a youth, pitch several heavy books from his 
 head by the movement of the scalp alone ; and he won 
 wagers by performing this feat. His father, uncle, grand- 
 father, and his three children possess the same power to the 
 .same unusual degree. This family became divided eight 
 generations ago into two branches ; so that the head of the 
 above-mentioned branch is cousin in the seventh degree to 
 the head of the other branch. This distant cousin resides 
 in another part of France ; and on being asked whether 
 he possessed the same faculty, immediately exhibited his 
 power. This case offers a good illustration how persistent 
 may be the transmission of an absolutely useless faculty, 
 probably derived from our remote semi-human progenitors; 
 
 Prof. W Turner, " Proc. Royal Soc. Edinburgh," 1866-67, p. 66.
 
 RUDIMENTS. 15 
 
 since many monkeys have, and frequently use the power, 
 of largely moving their scalps up and down. * 
 
 The extrinsic muscles which serve to move the external 
 ear, and the intrinsic muscles which move the different 
 parts, are in a rudimentary condition in man, and they all 
 belong to the system of the panniculus; they are also vari- 
 able in development, or at least in function. I have seen 
 one man who could draw the whole ear forward; other men 
 can draw it upward; another who could draw it backward;! 
 and from what one of these persons told me, it is probable 
 that most of us, by often touching our ears, and thus 
 directing our attention toward them, could recover some 
 power of movement by repeated trials. The power of erect- 
 ing and directing the shell of the ears to the various points 
 of the compass, is no doubt of the highest service to many 
 animals, as they thus perceive the direction of danger; but 
 I have never heard, on sufficient evidence, of a man who 
 possessed this power, the one which might be of use to him. 
 The whole external shell may be considered a rudiment, to- 
 gether with the various folds and prominences (helix and 
 anti-helix, tragus, and anti-tragus, etc.) which in the lower 
 animals strengthen and support the ear when erect, with- 
 out adding much to its weight. Some authors, however, 
 suppose that the cartilage of the shell serves to transmit 
 vibrations to the acoustic nerve; but Mr. Toynbee,J after 
 collecting all the known evidence on this head, concludes 
 that the external shell is of no distinct use. The ears of 
 the chimpanzee and orang are curiously like those of man, 
 and the proper muscles are likewise but very slightly 
 developed. I am also assured by the keepers in the 
 Zoological Gardens that these animals never move or erect 
 their ears; so that they are in an equally rudimentary condi- 
 tion with those of man, as far as function is concerned. 
 
 * See iny "Expression of the Emotions in Man and Animals," 1872, 
 p. 144. 
 
 j- Canestrini quotes Hyrtl. ("Annuario della Soc. dei Naturalist!," 
 Modena, 1867, p. 97) to the same effect. 
 
 J "The Diseases of the Ear," by J. Toynbee, F. R. S., 1860, p. 12. 
 A distinguished physiologist, Prof. Prey'er, informs me that he had 
 lately been experimenting on the function of the shell of the ear, and 
 has come to nearly the same conclusion as that given here. 
 
 ^Prof. A. Macalister, "Annals and Mag. of Nat. History," voL 
 vii, 1871, p. 343.
 
 16 THE DESCENT OF MAN. 
 
 Why these animals, as well as the progenitors of man, 
 should have lost the power, of erecting their ears, we cannot 
 say. It may be, though I am not satisfied with this view, 
 that owing to their arboreal habits and great strength they 
 were but little exposed to danger, and so during a length- 
 ened period moved their ears but little, and thus gradually 
 lost the power of moving them. This would be a parallel 
 case with that of those large and heavy birds, which, from 
 inhabiting oceanic islands, have not been exposed to the 
 attacks of beasts of prey, and have consequently lost the 
 power of using their wings for flight. The inability to 
 move the ears in man and several apes is, however, partly 
 compensated by the freedom with which they can move the 
 head in a horizontal plane, so as to catch sounds from all 
 directions. It has been asserted that the ear of man alone 
 possesses a lobule; but "a, rudiment of it is found in the 
 gorilla;"* and, as I hear from Prof. Preyer, it is not rarely 
 absent in the negro. 
 
 The celebrated sculptor, Mr. Woollier, informs me of 
 one little peculiarity in the external ear, which he has often 
 observed both in men and women, and of which he per- 
 ceived the full significance. His attention was first called 
 to the subject while at work on his figure of Puck, to 
 which he had given pointed ears. He was thus led to ex- 
 amine the ears of various monkeys, and subsequently more 
 carefully those of man. The peculiarity consists in a little 
 blunt point, projecting from the inwardly folded margin, 
 or helix. When present, it is developed at birth, and, ac- 
 cording to Prof. Ludwig Meyer, more frequently in man 
 than in woman. Mr. Woolner made an exact model of one 
 such case, and sent me the accompanying drawing. (Fig. 2. ) 
 These points not only project inward toward the center of 
 the ear, but of ten a little outward from its plane, so as to be 
 visible when the head is viewed from directly in front or 
 behind. They are variable in size, and somewhat in position, 
 standing either a little higher or lower ; and they sometimes 
 occur on one ear and not on the other. They are not con- 
 fined to mankind, for I observed a case in one of the spider- 
 monkeys (A teles Beelzebuth) in our Zoological Gardens; 
 and Mr. E. Ray Lankester informs me of another case jn a 
 chimpanzee in the gardens at Hamburg. The helix ob- 
 
 *Mr. St. George Mivart, " Elementary Anatomy," 1873, p. 396.
 
 RUDIMENTS. 
 
 viously consists of the extreme margin of the ear folded 
 inward ; and this folding appears to be in some manner 
 connected with the whole external ear being permanently 
 pressed backward. In many monkeys, which do not stand 
 high in the order, as baboons and some species of Macacus,* 
 the upper portion of the ear is slightly pointed, and the 
 margin is not at all folded inward ; but if the margin were, 
 to be thus folded, a slight point would necessarily project 
 inward toward the center, and probably a little outward 
 from the plane of the ear ; and this I believe to be their 
 origin in many cases. On the other hand, Prof * L. Meyer, 
 in an able paper recently published,! maintains that the 
 whole case is one of mere variability; 
 and that the projections are not real 
 ones, but are due to the internal 
 cartilage on each side of the points 
 not having been fully developed. I 
 am quite ready to admit that this is 
 the correct explanation in many in- 
 stances, as in those figured by Prof. 
 Meyer, in which there are several 
 minute points, or the whole margin 
 is sinuous. I have myself seen, 
 through the kindness of Dr. L. Down, 
 the ear of a microcephalous idiot, 
 on which there is a projection on the 
 outside of the helix, and not on the 
 inward folded edge, so that this point 
 can have no relation to a former apex 
 of the ear. Nevertheless in some 
 cases, my original view, that the points are vestiges of the tips 
 of formerly erect and pointed ears, still seems to me probable. 
 I think so from the frequency of their occurrence, and from the 
 general correspondence in position with that of the tip of a 
 pointed ear. In one case, of which a photograph has been 
 sent me, the projection is so large, that supposing, in ac- 
 cordance with Prof. Meyer's view, the ear to be made per- 
 
 See also some remarks, and the drawings of the ears of the Lem- 
 uroidea, in Messrs, Murie and Mivart's excellent paper in "Transact. 
 Zoolog. Soc.," vol. vii, 1869, pp. 6 and 90. 
 
 f Ueber das Darwin'sche Spitzolu- "Archiv filr Path. Anat. imd 
 Phys.," 1871, p. 485. 
 
 Fig. 2. Human Ear, mod- 
 eled and drawn by Mr. 
 Woolner. 
 
 a. The projecting point.
 
 18 THE DESCENT OF MAN. 
 
 feet by the equal development of the cartilage throughout 
 the whole extent of the margin, it would have covered fully 
 one-third of the whole eaV. Two cases have been commu- 
 nicated to me, one in North America and the other in 
 England, in which the upper margin is not at all folded 
 inward, but is pointed, so that it closely resembles the 
 pointed ear of an ordinary quadruped in outline. In one 
 of these cases, which was that of a young child, the father 
 compared the ear with the drawing which I have given* of 
 
 Kg. 3. Foetus of an Orang. Exact copy of a photograph, showing 
 the form of the ear at this early age. 
 
 the ear of a monkey, the CynopUhecus niger, and says that 
 their outlines are closely similar. If, in these two cases, 
 the margin had been folded inward in the normal manner, 
 an inward projection must have been formed. I may add 
 that in two other cases the outline still remains somewhat 
 pointed, although the margin of the upper part of the ear 
 is normally folded inward in one of them, however, very 
 narrowly. The above wood-cut (Fig. 3) is an accurate 
 copy of a photograph of the fretus of an orang (kindly sent 
 me by Dr. Nitsche), in which it may be seen how different 
 the pointed outline of the ear is at this period from ita 
 adult condition, when it bears a close general resemblance 
 
 *"The Expression of trie Emotions/' p. 136.
 
 RUDIMENTS. 19 
 
 to that of man. It is evident that the folding over of the 
 tip of such an ear, unless it changed greatly during its 
 further development, would give rise to a point projecting 
 inward. On the whole, it still seems to me probable that 
 the points in question are in some cases, both in man and 
 apes, vestiges of a former condition. 
 
 The nictitating membrane, or third eyelid, with its ac- 
 cessory muscles and other structures, is especially well 
 developed in birds, and is of much functional importance 
 to them, as it can be rapidly drawn across the whole eye- 
 ball. It is found in some reptiles and amphibians, and in 
 certain fishes, as in sharks. It is fairly well developed in 
 the two lower divisions of the mammalian series, namely, 
 in the monotremata and marsupials, and in some few of 
 the higher mammals, as in the walrus. But in man, the 
 quadrumana, and most other mammals, it exists, as is ad- 
 mitted by all anatomists, as a mere rudiment, called the 
 semilunar fold.* 
 
 The sense of smell is of the highest importance to the 
 greater number of mammals to some, as the ruminants, in 
 warning them of danger; to others, as the carnivora, in 
 finding their prey; to others, again, as the wild boar, for 
 both purposes combined. But the sense of smell is of 
 extremely slight service, if any, even to the dark colored 
 races of men, in whom it is much more highly developed 
 than in the white and civilized races, f Nevertheless it 
 does not warn them of danger, nor guide them to their 
 
 *Muller's "Elements of Physiology," Eng. translat., 1842, vol. ii, 
 p. 1117. Owen, "Anatomy of Vertebrates," vol. iii, p. 260; ibid, on 
 the Walrus, "Proc. Zoolog. Soc.," November 8, 1854. See also R. 
 Knox, "Great Artists and Anatomists," p. 106. This rudiment ap- 
 parently is somewhat larger in Negroes and Australians than in Euro- 
 peans, see Carl Vogt, " Lectures on Man," Eng. translat., p. 129. 
 
 f The account given by Humboldt of the power of smell possessed 
 by the natives of South America is well known, and has been con- 
 firmed by others . M. Houzeau (" Etudes sur les Facultes Mentales," 
 etc. , torn, i, 1872, p. 91) asserts that he repeatedly made experiments, 
 and proved that Negroes and Indians could recognize persons in the 
 dark by their odor. Dr. W. Ogle has made some curious observa- 
 tions on the connection between the power of smell and the coloring 
 matter of the mucous membrane of the olfactory region, as well as of 
 ths 8kin of the body. I have, therefore, spoken in the text of the 
 dark colored races having a finer Sense of smell than the white races. 
 See his paper, " Medico-Chirurgical Transactions," London, vol. liii, 
 1870, p. 276.
 
 20 THE DESCENT OF MAX. 
 
 food; nor does it prevent the Esquimaux from sleeping in 
 the most fetid atmosphere, nor many savages from eating 
 half-putrid meat. In Europeans the power differs greatly 
 in different individuals, as I am assured by an eminent 
 naturalist who possesses this sense highly developed, and 
 who has attended to the subject. Those who believe in the 
 principle of gradual evolution will not readily admit that 
 the sense of smell in its present state was originally acquired 
 by man as he now exists. He inherits the power in an 
 enfeebled and so far rudimentary condition, from some 
 early progenitor to whom it was highly serviceable, and by 
 whom it was continually used. In those animals which 
 have this sense highly developed, such as dogs and horses, 
 the recollection of persons and of places is strongly associ- 
 ated with their odor; and we can thus perhaps understand 
 how it is, as Dr. Maudsley has truly remarked,* that the 
 sense of smell in man "is singularly effective in recalling 
 vividly the ideas and images of forgotten scenes and places." 
 
 Man differs conspicuously from all the other Primates in 
 being almost naked. But a few short straggling hairs are 
 found over the greater part of the body in the man, and 
 fine down on that of the woman. The different races differ 
 much in hairiness; and in the individuals of the same race 
 the hairs are highly variable, not only in abundance, but 
 likewise in position; thus in some Europeans the shoulders 
 are quite naked, while in others they bear thick tufts of 
 hair, f There can be little doubt that the hairs thus scat- 
 tered over the body are the rudiments of the uniform hairy 
 coat of the lower animals. This view is rendered all the 
 more probable, as it is known that fine, short, and pale- 
 colored hairs on the limbs and other parts of the body, 
 occasionally become developed into "thickset, long, and 
 rather coarse dark hairs/' when abnormally nourished near 
 old-standing inflamed surfaces. J 
 
 I am informed by Sir James Paget that often several 
 members of a family have a few hairs in their eyebrows 
 much longer than the others; so that even this slight 
 
 * " The Physiology and Pathology of Mind," 2d edit., 1868, p. 134. 
 
 f Eschricht, Ueber die Richtung der Haare am raenschlichen KCr- 
 per, "Muller's Archiv fiir Anat. nnd Phys.," 1837, s. 47. I shall 
 often have to refer to this very curious paper. 
 
 J Paget, "Lectures on Surgical Pathology," 1853, vol. i, p. 71.
 
 RUDIMENTS. 21 
 
 peculiarity seems to be inherited. These hairs, too, seem 
 to have their representatives; for in the chimpanzee, and in 
 certain species of Macacus, there are scattered hairs of con- 
 siderable length rising from the naked skin above the eyes, 
 and corresponding to our eyebrows; similar long hairs pro- 
 ject from the hairy covering of the superciliary ridges in 
 Borne baboons. 
 
 The fine \vool-like hair, or so-called lanugo, with which 
 the human foetus during the sixth month is thickly cov- 
 ered, offers a more curious case. It is first developed, dur- 
 ing the fifth month, on the eyebrows and face, and espe- 
 cially round the mouth, where it is much longer than that 
 on the head. A mustache of this kind was observed by 
 Eschricht* on a female foetus; but this is not so surprising 
 a circumstance as it may at first appear, for the two sexes 
 generally resemble each other in all external characters 
 during an early period of growth. The direction and 
 arrangement of the hairs on all parts of the foetal body are 
 the same as in the adult, but are subject to much varia- 
 bility. The whole surface, including even the forehead 
 and ears, is thus thickly clothed; but it is a significant fact 
 that the palms of the hands and the soles of the feet are 
 quite naked, like the inferior surfaces of all four extremi- 
 ties in most of the lower animals. As this can hardly be 
 an accidental coincidence, the woolly covering of the foetus 
 probably represents the first permanent coat of hair in those 
 mammals which are born hairy. Three or four cases have 
 been recorded of persons born with their whole bodies and 
 faces thickly covered with fine long hairs; and this strange 
 condition is strongly inherited, and is correlated with an 
 abnormal condition of the teeth, f Prof. Alex. Brandt in- 
 forms me that he has compared the hair from the face of a 
 man thus characterized, aged thirty-five, with the lanugo 
 of a foetus, and finds it quite similar in texture; therefore, 
 as he remarks, the case may be attributed to an arrest of 
 development in the hair, together with its continued 
 growth. Many delicate children, as I have been assured 
 by a surgeon to a hospital for children, have their backs 
 
 *Eschricht, ibid., s. 40, 47. 
 
 f See my " Variation of Animals and Plants under Domestication,** 
 vol. ii, p. 327, Prof. Alex. Brandt has recently sent me an additional 
 case of a father and son, born in Russia, with these peculiarities. I 
 tave receiver] drawings of both from Pans.
 
 22 THE DESCENT OF MAN. 
 
 covered by rather long silky hairs; and such cases probably 
 come under the same head. 
 
 It appears as if the posterior molar or wisdom teeth were 
 tending to become rudimentary in the more civilized races 
 of man. These teeth are rather smaller than the other 
 molars, as is likewise the case with the corresponding teeth 
 in the chimpanzee and orang; and they have only two 
 separate fangs. They do not cut through the gums till 
 about the seventeenth year, and I have been assured that 
 they are much more liable to decay, and are earlier lost 
 than the other teeth; but this is denied by some eminent 
 dentists. They are also much more liable to vary, both in 
 structure and in the period of their development, than the 
 other teeth.* In the Melanian races, on the other hand, 
 the wisdom teeth are usually furnished with three separate 
 fangs, and are generally sound; they also differ from the 
 other molars in size, less than in the Caucasian races, f 
 Prof. Schaaffhausen accounts for this difference between 
 the races by " the posterior dental portion of the jaw being 
 always shortened" in those that are civilized, | and this 
 shortening may, I presume, be attributed to civilized men 
 habitually feeding on soft, cooked food, and thus using 
 their jaws less. I am informed by Mr. Brace that it is 
 becoming quite a common practice in the United States to 
 remove some of the molar teeth of children, as the jaw 
 does not grow large enough for the perfect development of 
 the normal number. 
 
 With respect to the alimentary canal, I have met with an 
 account of only a single rudiment, namely the vermiform 
 appendage of the cascum. The caecum is a branch or diver- 
 ticulum of the intestine, ending in a cul-de-sac, and is ex- 
 tremely long in many of the lower vegetable-feeding mam- 
 
 * Dr. Webb, "Teeth in Man and the Anthropoid Apes," as quoted 
 by Dr. C. Carter Blake in "Anthropological Review," July, 1867, 
 p. 299. 
 
 fOwen, "Anatomy of Vertebrates," vol. iii, pp. 320, 321 and 325. 
 
 j " On the Primitive Form of the Skull," Eng. translat. in" Anthrop- 
 ological Review," Oct. 1868, p. 426. 
 
 Prof. Montegazza writes to me from Florence, that he has lately 
 been studying the last molar teeth in the different races of man, and 
 has come to the same conclusion as that given in my test, viz. : that 
 in the higher or civilized races they are on the road toward atrophy 
 or elimination.
 
 RUDIMENTS. 23 
 
 mals. In the marsupial koala it is actually more than 
 thrice as long as the whole body.* It is sometimes produced 
 into a long gradually tapering point, and is sometimes con- 
 stricted in parts. It appears as if, in consequence of 
 changed diet or habits, the caecum had become much short- 
 ened in various animals, the vermiform appendage being 
 left as a rudiment of the shortened part. That this ap- 
 pendage is a rudiment, we may infer from its small size, and 
 from the evidence which Prof. Canestrini f has collected of its 
 variability in man. It is occasionally quite absent, or again 
 is largely developed. The passage is sometimes completely 
 closed for half or two-thirds of its length, with the terminal 
 part consisting of a flattened solid expansion. In the orang 
 this appendage is long and convoluted : in man it arises 
 from the end of the short caecum, and is commonly from 
 four to five inches in length, being only about the third of 
 an inch in diameter. Not only is it useless, but it is some- 
 times the cause of death, of which fact I have lately heard 
 two instances : this is due to small hard bodies, such as 
 seeds, entering the passage, and causing inflammation. J 
 
 In some of the lower Quadrumana, in the Lemuridae and 
 Carnivora, as well as in many marsupials, there is a pas- 
 sage near the lower end of the humerus, called the supra- 
 condyloid foramen, through which the great nerve of the 
 fore limb and often the great artery pass. Now in the 
 humerus of man, there is generally a trace of this passage, 
 which is sometimes fairly well developed, being formed by 
 a depending hook-like process of bone, completed by a band 
 of ligament. Dr. Struthers, who has closely attended to 
 the subject, has now shown that this peculiarity is some- 
 times inherited, as it has occurred in a father, and in no less 
 
 * Owen, " Anatomy of Vertebrates," vol. iii, pp. 416, 434, 441. 
 
 f'Annuario della Soc. d. Nat.," Modena, 1867, p, 94. 
 
 JM. C. Martins ("De I'Unite Organique," in "Revue des Deux 
 Mondes," June 15, 1862, p. 16), and Hackel (" Generslle Morpholo- 
 gic," B. ii, s. 278), have both remarked on the singular fact of this 
 rudiment sometimes causing death. 
 
 With respect to inheritance, see Dr. Struthers in tli "Lancet," 
 Feb. 15, 1873, and another important paper, ibid., Jan. 84, 1863, p. 
 83. Dr. Knox, as I am informed, was the first anatomist who drew 
 attention to this peculiar structure in man ; see his ' ' Great Artists 
 and Anatomists," p. 63. See also an important memoir on this pro- 
 cess by Dr. Gruber, in the " Bulletin de 1'Acad. Imp. de St. PSters- 
 bourg," torn, zii, 1867, p. 448-
 
 24 THE DESCENT OF MAN. 
 
 than four out of his seven children. When present, the 
 great nerve invariably passes through it ; and this clearly 
 indicates that it is the homologue and rudiment of the 
 supra-condyloid foramen of the lower animals. Prof. 
 Turner estimates, as he informs me, that it occurs in about 
 one per cent, of recent skeletons. But if the occasional 
 development of this structure in man is, as seems probable, 
 due to reversion, it is a return to a very ancient state of 
 things, because in the higher Quadrumana it is absent. 
 
 There is another foramen or perforation in the humeras, 
 occasionally present in man, which may be called the inter- 
 condyloid. This occurs, but not constantly, in various an- 
 thropoid and other apes,* and likewise in many of the lower 
 animals. It is remarkable that this perforation seems to 
 have been present in man much more frequently during 
 ancient times than recently. Mr. Buskf has collected the 
 following evidence on this head: Prof. Broca "noticed the 
 perforation in four and a half per cent, of the arm-bones 
 collected in the ' Cimetiere du Sud/ at Paris; and in the 
 Grotto of Orrony, the contents of which are referred to the 
 Bronze period, as many as eight humeri out of thirty-two 
 were perforated ; but this extraordinary proportion, he 
 thinks, might be due to the cavern having been a sort of 
 'family vault/ Again, M. Dupont found thirty per cent, 
 of perforated bones in the caves of the Valley of the Lesse, 
 belonging to the Keindeer period; while M. Leguay, in a 
 sort of dolmen at Argenteuil, observed twenty-five per cent, 
 to be perforated; and M. Pruner-Bey found twenty-six per 
 cent, in the same condition in bones from Vaureal. Nor 
 should it be left unnoticed that M. Pruner-Bey states that 
 this condition is common in Gruanche skeletons." It is an 
 interesting fact that ancient races, in this and several other 
 cases, more frequently present structures which resemble 
 those of the lower animals than do the modern. One chief 
 cause seems to be that the ancient races stand somewhat 
 
 *Mr. St. George Mivart, "Transact. Pliil. Soc.," 1867, p. 310. 
 
 \" On the Caves of Gibraltar," "Transact. Internat. Congress of 
 Prehist. Arch." Third Session, 1869, p. 159. Prof. Wyrnan has lately 
 shown (Fourth Annual Report, Peabody Museum, 1871, p. 20), that 
 this perforation is present in thirty-one per cent, of some human re- 
 mains from ancient mounds in the Western United States, and in 
 Florida. It frequently occurs in the negro.
 
 RUDIMENTS. 25 
 
 nearer in the long line of descent to their remote animal- 
 like progenitors. 
 
 In man, the os coccyx, together with certain other verte- 
 brae hereafter to be described, though functionless as a tail, 
 plainly represent this part in other vertebrate animals. At 
 an early embryonic period it is free, and projects beyond 
 the lower extremities; as may be seen in the drawing (Fig. 
 1) of a human embryo. Even after birth it has been known, 
 in certain rare and anomalous cases,* to form a small ex- 
 ternal rudiment of a tail. The os coccyx is short, usually 
 including only four vertebras, all anchylosed together; and 
 these are in a rudimentary condition, for they consist, with 
 the exception of the basal one, of the centrum alone.f 
 They are furnished with some small muscles; one of which, 
 as I am informed by Prof. Turner, has been expressly de- 
 scribed by Theile as a rudimentary repetition of the exten- 
 sor of the tail, a muscle which is so largely developed in 
 many mammals. 
 
 The spinal cord in man extends only as far downward as 
 the last dorsal or first lumbar vertebra; but a thread-like 
 structure (the filum terminate) runs down the axis of the 
 sacral part of the spinal canal, and even along the back of 
 the coccygeal bones. The upper part of this filament, as 
 Prof. Turner informs me, is undoubtedly homologous with 
 the spinal cord ; but the lower part apparently consists merely 
 of the pia mater, or vascular investing membrane. Even 
 in this case the os coccyx may be said to possess a ves- 
 tige of so important a structure as the spinal cord, though 
 no longer inclosed within a bony canal. -The following 
 fact, for which I am also indebted to Prof. Turner, 
 shows how closely the os coccyx corresponds with the 
 true tail in the lower animals: Luschka has recently dis- 
 covered at the extremity of the coccygeal bones a very pe- 
 culiar convoluted body, which is continuous with the mid- 
 dle sacral artery; and this discovery led Krause and Meyer 
 
 * Quatrefages lias lately collected the evidence on this subject. 
 " Revue des Cours Scientifiques," 1867-1868, p. 625. In 1840 Fleisch- 
 ruann exhibited a human foetus bearing a free tail, which, as is not 
 always the case, included vertebral bodies; and this tail was critically 
 examined by the many anatomists present at the meeting of natural- 
 ists at Erlangen (see Marshall in ' ' Niederlandischen Archiv f iir Zoolo- 
 gie," December, 1871). 
 
 f Owen, "On the Nature of Iambs," 1849, p. 114.
 
 26 TUB DESCENT OF MAN. 
 
 to examine the tail of a monkey (Macacus), and of a cat, 
 in both of which they found a similarly convoluted body, 
 though not at the extremity. 
 
 The reproductive system offers various rudimentary struct- 
 ures; but these differ in one important respect from the 
 foregoing cases. Here we are not concerned with the ves- 
 tige of a part which does not belong to the species in 
 an efficient state, but with a part efficient in the one 
 sex, and represented in the other by a mere rudiment. 
 Nevertheless, the occurrence of such rudiments is as diffi- 
 cult to explain, on the belief of the separate creation of 
 each species, as in the foregoing cases. Hereafter I shall 
 have to recur to these rudiments, and shall show that their 
 presence generally depends merely on inheritance, that is, 
 on parts acquired by one sex having been partially trans- 
 mitted to the other. I will in this place only give some in- 
 stances of such rudiments. It is well known that in the 
 males of all mammals, including man, rudimentary mammae 
 exist. These in several instances have become well de- 
 veloped, and have yielded a copious supply of milk. Their 
 essential identity in the two sexes is likewise shown by 
 their occasional sympathetic enlargement in both during 
 an attack of the measles. The vesicula prostatica, which 
 has been observed in many male mammals, is now universally 
 acknowledged to be the liomologue of the female uterus, 
 together with the connected passage. It is impossible to 
 read Leuckart's able description of this organ, and his 
 reasoning, without admitting the justness of his conclusion. 
 This is especially clear in the case of those mammals in 
 which the true female uterus bifurcates, for in the males of 
 these the vesicula likewise bifurcates.* Some other rudi- 
 mentary structures belonging to the reproductive system 
 might have been here adduced, f 
 
 The bearing of the three great classes of facts now given 
 is unmistakable. But it would be superfluous fully to recap- 
 itulate the line of argument given in detail in my " Origin 
 of Species." The homological construction of the whole 
 
 *Leuckart, in Todd's " Cyclop, of Anat.," 1849-52, vol. iv, p. 1415. 
 In man this organ is only from three to six lines in length, but, like 
 so many other rudimentary parts, it is variable in development as 
 well as in other characters. 
 
 I See, on this subject, Owen, "Anatomy of Vertebrates," vol. iii, 
 pp. 675, 676, 706.
 
 RUDIMENTS. 27 
 
 frame in the members of the same class is intelligible, if we 
 admit their descent from a common progenitor, together 
 with their subsequent adaptation to diversified conditions. 
 On any other view, the similarity of pattern between the 
 hand of a man or monkey, the foot of a horse, the nipper 
 of a seal, the wing of a bat, etc., is utterly inexplicable.* 
 It is no scientific explanation to assert that they have all 
 been formed on the same ideal plan. With respect to de- 
 velopment, we can clearly understand, on the principle of 
 variations supervening at a rather late embryonic period, 
 and being inherited at a corresponding period, how it is 
 that the embryos of wonderfully different forms should still 
 retain, more or less perfectly, the structure of their common 
 progenitor. No other explanation has ever been given of 
 the marvelous fact that the embryos of a man, dog, seal, 
 bat, reptile, etc., can at first hardly be distinguished from 
 each other. In order to understand the existence of rudi- 
 mentary organs, we have only to suppose that a former pro- 
 genitor possessed the parts in question in a perfect state, 
 and that under changed habits of life they became greatly 
 reduced, either from simple disuse, or through the natural 
 sfliection of those individuals which were least encumbered 
 with a superfluous part, aided by the other means pre- 
 viously indicated. 
 
 * Prof. Bianconi, in a recently published work, illustrated by ad- 
 mirable engravings (" La Theorie Darwinienne et la creation dite in- 
 d6pendante," 1874), endeavors to show that homological structures, 
 in the above and other cases, can be fully explained on mechanical 
 principles, in accordance with their uses. No one has shown so well, 
 how admirably such structures are adapted for their final purpose ; 
 and this adaptation can, as I believe, be explained through natural 
 selection. In considering the wing of a bat, he brings forward (p. 
 218) what appears to me (to use Auguste Comte's words) a mere met- 
 aphysical principle, namely, the preservation "in its integrity of the 
 mammalian nature of the animal." In only a few cases does he dis- 
 cuss rudiments, and then only those parts which are partially 
 rudimentary, such as the little hoofs of the pig and ox, which do not 
 touch the ground ; these he shows clearly to be of service to the ani- 
 mal. It is unfortunate that he did not consider such cases as the 
 minute teeth, which never cut through the jaw in the ox, or the 
 mammae of male quadrupeds, or the wings of certain beetles, existing 
 under the soldered wing-covers, or the vestiges of the pistil and 
 stamens in various flowers, and many other such cases. Although I 
 greatly admire Prof. Bianconi's work, yet the belief now held by 
 most naturalists seems to me left unshaken, that homological struct- 
 ures are inexplicable on the principle of mere adaptation.
 
 28 THE DESCENT OF MAN. 
 
 Thus we can understand how it has come to pass that 
 man and all other vertebrate animals have been con- 
 structed on the same general model, why they pass through 
 the same early stages of development, and why they retain 
 certain rudiments in common. Consequently we ought 
 frankly to admit their community of descent ; to take any 
 other view, is to admit that our own structure, and that oS 
 all the animals around us, is a mere snare laid to entrap our 
 judgment. This conclusion is greatly strengthened, if we 
 look to the members of the whole animal series, and con- 
 sider the evidence derived from their affinities or classifica- 
 tion, their geographical distribution and geological succes- 
 sion. It is only our natural prejudice, and that arrogance 
 which made our forefathers declare that they were de- 
 scended from demi-gods, which leads us to demur to this 
 conclusion. But the time will before long come, when it 
 will be thought wonderful that naturalists, who were well 
 acquainted with the comparative structure and development 
 of man, and other mammals, should have believed that 
 each was the work of a separate act of creation.
 
 MANNER OF DEVELOPMENT. 
 
 CHAPTER II. 
 
 ON THE MANNER OF DEVELOPMENT OF MAN FROM SOME 
 LOWER FORM. 
 
 Variability of body and inind in man Inheritance Causes of varia- 
 bility Laws of variation the same in man as in the lower ani- 
 mals Direct action of the conditions of life Effects of the 
 increased use and disuse of parts Arrested development 
 Keversion Correlated variation Rate of increase Checks to 
 increase Natural selection Man the most dominant animal in 
 the world Importance of his corporeal structure The causes 
 which have led to his becoming erect Consequent changes of 
 structure Decrease in size of the canine teeth Increased size 
 and altered shape of the skull Nakedness Absence of a tail 
 Defenceless condition of man. 
 
 IT is manifest that man is now subject to much variabil- 
 ity. No two individuals of the same race are quite alike. 
 We may compare millions of faces, and each will be dis- 
 tinct, There is an equally great amount of diversity in the 
 proportions and dimensions of the various parts of the body; 
 the length of the legs being one of the most variable points.* 
 Although in some quarters of the world an elongated skull, 
 and in other quarters a short skull prevails, yet there is 
 great diversity of shape even within the limits of the same 
 race, as with the aborigines of America and South Australia 
 the latter a race " probably as pure and homogeneous in 
 blood, customs, and language as any in existence" and 
 even with the inhabitants of so confined an area as the 
 Sandwich Islands.f An eminent dentist assures, me that 
 
 * " Investigations in Military and Anthropolog. Statistics of Ameri- 
 can Soldiers," by B. A. Gould, 1869, p. 256. 
 
 f With respect to the " Cranial forms of the American Aborigines," 
 see Dr. Aitken Meigs in "Proc. Acad. Nat. Sci.," Philadelphia, May, 
 1868. On the Australians, see Huxley, in Lyell's " Antiquity of 
 Man," 1863, p. 87. On the Sandwich Islanders, Prof. J. Wyman, 
 "Observations on Crania," Boston, 1868, p. 18.
 
 30 THE DESCENT OF MAN. 
 
 there is nearly as much diversity in the teeth as in the feat- 
 ures. The chief arteries' so frequently run in abnormal 
 courses, that it has been found useful for surgical purposes 
 to calculate from 1040 corpses how often each course pre- 
 vails.* The muscles are eminently variable : thus those of 
 the foot were found by Prof. Turner f not to be strictly 
 alike in any two out of fifty bodies ; and in some the de- 
 viations were considerable. He adds, that the power of 
 performing the appropriate movements must have been 
 modified in accordance with the several deviations. Mr. 
 J. Wood has recorded \ the occurrence of 295 muscular 
 variations in thirty-six subjects, and in another set of the 
 same number no less than 558 variations; those occurring 
 on both sides of the body being only reckoned as one. In 
 the last set, not one body out of the thirty-six was " found 
 totally wanting in departures from the standard descrip- 
 tions of the muscular system given in anatomical text 
 books." A single body presented the extraordinary num- 
 ber of twenty-five distinct abnormalities. The same mus- 
 cle sometimes varies in many ways : thus Prof. Macalister 
 describes no less than twenty distinct variations in the 
 palmaris accessorius. 
 
 The famous old anatomist, Wolff, | insists that the inter- 
 nal viscera are more variable than the external parts: Nulla 
 particula est qua non aliter et aliter in aliis se liabeat 
 homimlus. He has even written a treatise on the choice 
 of typical examples of the viscera for representation. A 
 discussion on the beau-ideal of the liver, lungs, kidneys, 
 etc., as of the human face divine, sounds strange in our 
 ears. 
 
 The variability or diversity of the mental faculties in 
 men of the same race, not to mention the greater differ- 
 ences between the men of distinct races, is so notorious that 
 not a word need here be caid. So it is with the lower ani- 
 mals. All who have had charge of menageries admit this 
 fact, and we see it plainly in our dogs and other domestic 
 
 * "Anatomy of the Arteries," by K. Quain. Preface, vol. i, 1844. 
 f "Transact. Royal Soc. Edinburgh," vol. xxiv, pp. 175, 189. 
 t " Proc. Royal Soc.," 1867, p. 544 ; also 1868, pp. 483, 524. There 
 is a previous paper, 1866, p. 229. 
 
 "Proc. R. Irish Academy," vol. x, 1868, p. 141. 
 j " Act. Acad. St. Petersburg," 1778, part ii, p. 217.
 
 MANNER OF DEVELOPMENT. 31 
 
 animals. Brehm especially insists that each individual 
 monkey of those which he kept tame in Africa had its own 
 peculiar disposition and temper: he mentions one baboon 
 remarkable for its high intelligence; and the keepers in the 
 Zoological Gardens pointed out to me a monkey, belonging 
 to the New World division, equally remarkable for intelli- 
 gence. Eengger, also, insists on the diversity in the vari- 
 ous mental characters of the monkeys of the same species 
 which he kept in Paraguay; and this diversity, as he adds, 
 is partly innate, and partly the result of the manner in 
 which they have been treated or educated.* 
 
 I have elsewhere f so fully discussed the subject of In- 
 heritance, that I need here add hardly any thing. A 
 greater number of facts have been collected with respect to 
 the transmission of the most trifling, as well as of the most 
 important characters in man, than in any of the lower ani- 
 mals; though the facts are copious enough with respect to 
 the latter. So in regard to mental qualities, their trans- 
 mi^sion is manifest in our dogs, horses, and other domestic 
 animals. Besides special tastes and habits, general intelli- 
 gence, courage, bad and good temper, etc., are certainly 
 transmitted. With man we see similar facts in almost 
 every family ; and we now know, through the admirable 
 labors of Mr. Galtonf that genius which implies a wonder- 
 fully complex combination of high faculties, tends to be 
 inherited; and, on the other hand, it is too certain that in- 
 sanity and deteriorated mental powers likewise run in 
 families. 
 
 With respect to the causes of variability, we are in all 
 cases very ignorant; but we can see that in man as in the 
 lower animals, they stand in some relation to the conditions 
 to which each species has been exposed during several gen- 
 erations. Domesticated animals vary more than those in a 
 state of nature; and this is apparently due to the diversified 
 and changing nature of the conditions to which they have 
 been subjected. In this respect the different races of man 
 
 *Brehm, " TMerleben," B. i, s. 58, 87. Ttengger, " Saugethiere 
 von Paraguay," s. 57. 
 
 f "Variation of Animals and Plants under Domestication," vol. ii, 
 chap. xii. 
 
 t" Hereditary Genius: an Inqniry into its Laws and Conse- 
 quences," 1869.
 
 32 THE DESCENT OF MAN. 
 
 resemble domesticated animals, and so do the individuals 
 of the same race, when inhabiting a very wide area, like 
 that of America. We see the influence of diversified con- 
 ditions in the more civilized nations; for the members be- 
 longing to different grades of rank, and following different 
 occupations, present a greater range of character than do 
 the members of barbarous nations. But the uniformity of 
 savages has often been exaggerated, and in some cases can 
 hardly be said to exist.* It is, nevertheless, an error to 
 speak of man, even if we look only to the conditions to 
 which he has been exposed, as " far more domesticated "f 
 than any other animal. Some savage races, such as the 
 Australians, are not exposed to more diversified conditions 
 than are many species which have a wide range. In an- 
 other and much more important respect, man differs widely 
 from any strictly domesticated animal; for his breeding has 
 never long been controlled, either by methodical or uncon- 
 scious selection. No race or body of men has been so com- 
 pletely subjugated by other men, as that certain individuals 
 should be preserved, and thus unconsciously selected, from 
 somehow excelling in utility to their masters. Nor have 
 certain male and female individuals been intentionally 
 picked out and matched, except in the well-known case of 
 the Prussian grenadiers; and in this case man obeyed, as 
 might have been expected, the law of methodical selection; 
 for it is asserted that many tall men were reared in the 
 villages inhabited by the grenadiers and their tall wives. 
 In Sparta, also, a form of selection was followed, for it was 
 enacted that all children should be examined shortly after 
 birth; the well-formed and vigorous being preserved, the 
 others left to perish. J 
 
 *Mr. Bates remarks (" The Naturalist on the Amazons," 1863, vol. 
 ii, p. 159), with respect to the Indians of the same South American 
 tribe, "No two of them were at all similar in the shape of the head ; 
 one man had an oval visage with fine features, and another was 
 quite Mongolian in breadth and prominence of cheek, spread of nos- 
 trils, and obliquity of eyes." 
 
 f Blumenbach, " Treatises on Anthropolog.," Eug. translat., 1865, 
 p. 205. 
 
 f Mitford's "History of Greece," vol. i, p. 282. It appears also 
 from a passage in Xenophon's "Memorabilia," B. ii, 4 (to which my 
 attention has been called by the Rev. J. N. Hoare), that it was a well 
 recognized principle with the Greeks, that men ought to select their 
 wives with a view to the health and vigor of their children. The
 
 MANNER OF DEVELOPMENT. 33 
 
 If we consider all the races of man as forming a single 
 species, his range is enormous; but some separate races, as 
 the Americans and Polynesians, have very wide ranges. It 
 is a well-known law that widely ranging species are much 
 more variable than species with restricted ranges; and the 
 variability of man may with mere truth be compared with 
 that of widely ranging species, than with that of domesti- 
 cated animals. 
 
 Not only does variability appear to be induced in man 
 and the lower animals by the same general causes, but in 
 both the same parts of the body are affected in a closely 
 analogous manner. This has been proved in such full de- 
 tail by Godron and Quatrefages, that I need here only refer 
 to their works.* Monstrosities, which graduate into slight 
 variations, are likewise so similar in man and the lower 
 animals, that the same classification and the same terms 
 can be used for both, as has been shown by Isidore Geoffroy 
 St.-Hilaire.f In my work on the variation of domestic 
 animals, I have attempted to arrange in a rude fashion the 
 laws of variation under the following heads : The direct 
 and definite action of changed conditions, as exhibited by 
 
 Grecian poet, Theognis, who lived 550 B.C., clearly saw how import- 
 ant selection, if carefully applied, would be for the improvement of 
 mankind. He saw, likewise, that wealth often checks the proper 
 action of sexual selection. He thus writes : 
 
 " With kine and horses, Kurnus! we proceed 
 By reasonable rules, and choose a breed 
 For profit and increase, at any price; 
 Of a sound stock, without defect or vice. 
 But, in the daily matches that we make, 
 The price is every thing: for money's sake, 
 Men marry: women are in marriage given 
 The churl or ruffian, that in wealth has thriven. 
 May match his offspring with the proudest race; 
 Thas every thing is mix'd, noble and base! 
 If then in outward manner, form, and mind, 
 You find us a degraded, motley kind, 
 Wonder no more, my friend! the cause is plain, 
 And to lament the consequence is vain." 
 (The works of J. Hookham Frere, vol. ii, 1872, p. 334.) 
 
 * Godron, "De 1'Espece," 1859, torn, ii, livre 3. Quatrefages, 
 " Unite de 1'Espece Humaine," 1861. Also Lectures on Anthropol- 
 ogy, given in the " Revue des Cours Scientifiques," 1866-1868. 
 
 Hist. Gen. et Part, des Anomalies de rOrganisation," in three 
 torn, i, 1832. 
 
 f " Hisl 
 
 volumes,
 
 34 THE DESCENT OF MAN. 
 
 all or nearly all the individuals of the same species, varying 
 in the same manner under the same circumstances. The 
 effects of the long-contiiiued use or disuse of parts. The 
 cohesion of homologous parts. The variability of multiple 
 parts. Compensation of growth ; but of this law I have 
 found no good instance in the case of man. The effects of 
 the mechanical pressure of one part on another; as of the 
 pelvis on the cranium of the infant in the womb. Arrests 
 of development, leading to the diminution or suppression 
 of parts. The reappearance of long-lost characters through 
 reversion. And lastly, con-elated variation. And these 
 Bo-called laws apply equally to man and the lower animals ; 
 and most of them even to plants. It would be superfluous 
 here to discuss all of them; * but several are so important, 
 that they must be treated at considerable length. 
 
 The Direct and Definite Action of Changed Conditions. 
 This is a most perplexing subject. It cannot be denied 
 that changed conditions produce some, and occasionally a 
 considerable effect, on organisms of all kinds; and it seems 
 at first probable that if sufficient time were allowed this 
 would be the invariable result. But I have failed to obtain 
 clear evidence in favor of this conclusion; and valid reasons 
 may be urged on the other side, at least as far as the in- 
 numerable structures are concerned which are adapted for 
 special ends. There can, however, be no doubt that 
 changed conditions induce an almost indefinite amount of 
 fluctuating variability, by which the whole organization is 
 rendered in some degree plastic. 
 
 In the United States, above 1,000,000 soldiers, who 
 served in the late war, were measured, and the States in 
 which they were born and reared were recorded, f From 
 this astonishing number of observations it is proved that 
 local influences of some kind act directly on stature; and 
 we further learn that " the State where the physical growth 
 has in great measure taken place, and the State of birth, 
 
 *I have fully discussed these laws in my "Variation of Animals 
 and Plants under Domestication," vol. ii, chap, xxii and xxiii. M. J. 
 P. Durand has lately (1868) published a valuable essay " De 1'Influ- 
 ence des Milieux," etc. He lays much stress, in the case of plants, 
 on the nature of the soil. 
 
 f "Investigations in Military and Anthrop. Statistics," etc., 1869, 
 by B. A. Gould, pp. 93, 107, 126, 131, 134.
 
 MANNER OF DEVELOPMENT. 35 
 
 which indicates the ancestry, seem to exert a marked in- 
 fluence on the stature." For instance, it is established, 
 " that residence in the Western States, during the years of 
 growth, tends to produce increase of stature." On the 
 other hand, it is certain that with sailors, their life delays 
 growth, as shown "by the great difference between the 
 statures of soldiers and sailors at the ages of seventeen and 
 eighteen years." Mr. B. A. Gould endeavored to ascertain 
 the nature of the influences which thus act on stature; but 
 he arrived only at negative results, namely, that they did 
 not relate to climate, the elevation of the land, soil, nor 
 even "in any controlling degree" to the abundance or the 
 need of the comforts of life. This latter conclusion is 
 directly opposed to that arrived at by Villerme, from the 
 statistics of the height of the conscripts in different parts 
 of France. When we compare the differences in stature 
 between the Polynesian chiefs and the lower orders within 
 the same islands, or between the inhabitants of the fertile 
 volcanic and low ban en coral islands of the same ocean,* 
 or again between the Fuegians on the eastern and western 
 shores of their country, where the means of subsistence are 
 very different, it is scarcely possible to avoid the conclusion 
 that better food and greater comfort do influence stature. 
 But the preceding statements show how difficult it is to 
 arrive at any precise result. Dr. Beddoe has lately proved 
 that, with the inhabitants of Britain, residence in towns 
 and certain occupations have a deteriorating influence on 
 height; and he infers that the result is to a oertain extent 
 inherited, as is likewise the case in the United States. Dr. 
 Beddoe further believes that wherever a " race attains its 
 maximum of physical development, it rises highest in 
 energy and moral vigor, "f 
 
 Whether external conditions produce any other direct 
 effect on man is not known. It might have been expected 
 that differences of climate would have had a marked influ- 
 ence, inasmuch as the lungs and kidneys are brought into 
 
 *For the Polynesians, see Prichard's "Physical Hist, of Man- 
 kind," vol. v, 1847, pp. 145, 283. Also Godron, " De 1'Espece," torn, 
 ii, p. 289. There is also a remarkable difference in appearance be- 
 tween the closely allied Hindoos inhabiting the Upper Ganges and 
 Bengal ; see Elphinstone's "History of India," vol. i, p. 324. 
 
 f " Memoirs, Anthropolog. Soc.." vol. iii, 1867-69, pp. 561, 565.
 
 36 THE DESCENT OF MAN. 
 
 activity under a low temperature, and the liver and skin 
 under a high one.* It was formerly thought that the color 
 of the skin and the character of the hair were determined 
 by light or heat; and although it can hardly be denied that 
 some effect is thus produced, almost all observers now agree 
 that the effect has been very small,, even after exposure 
 during many ages. But this subject will be more properly 
 discussed when we treat of the different races of mankind. 
 With our domestic animals there are grounds for believing 
 that cold and damp directly affect the growth of the hair; 
 but I have not met with any evidence on this head in the 
 case of man. 
 
 Effects of the Increased Use and Disuse of Parts. It is 
 well known that use strengthens the muscles in the individ- 
 ual, and complete disuse, or the destruction of the proper 
 nerve, weakens them. When the eye is destroyed, the optio 
 nerve often becomes atrophied. When an artery is tied, 
 the lateral channels increase not only in diameter, but in 
 the thickness and strength of their coats. When one kid- 
 ney ceases to act from disease, the other increases in size, 
 and does double work. Bones increase not only in thick- 
 ness, but in length, from carrying a greater weight, f Dif- 
 ferent occupations, habitually followed, lead to changed 
 proportions in various parts of the body. Thus it was as- 
 certained by the United States Commission! that the legs 
 of the sailors employed in the late war were longer by 0.217 
 of an inch than those of the soldiers, though the sailors 
 were on an average shorter men ; while their arms were 
 shorter by 1.09 of an inch, and therefore, out of proportion, 
 shorter in relation to their lesser height. This shortness of 
 the arms is apparently due to their greater use, and is an 
 unexpected result: but sailors chiefly use their arms in pull- 
 ing, and not in supporting weights. With sailors, the girth 
 of the neck and the depth of the instep are greater, while 
 
 *Dr. Brakenridge, "Theory of Diathesis," ''Medical Times," 
 June 19 and July 17, 1869. 
 
 f 1 have given authorities for these several statements in my 
 " Variation of Animals under Domestication," vol. ii, pp. 297-300- 
 Dr. Jaeger, " Ueber das Langenwachsthuni der Knochen," " Jenaia 
 chen Zeitschrift," B. v, Heft. i. 
 
 J " Investigations," etc. By B. A. Gould, 1869, p. 388
 
 MANNER OF DEVELOPMENT. 37 
 
 the circumference of the chest, waist, and hips is less than 
 in soldiers. 
 
 "Whether the several foregoing modifications would be- 
 come hereditary, if the same habits of life were followed 
 during many generations, is not known, but it is probable. 
 Rengger* attributes the thin legs and thick arms of the 
 Payaguas Indians to successive generations having passed 
 nearly their whole lives in canoes, with their lower extremi- 
 ties motionless. Other writers have come to a similar con- 
 clusion in analogous cases. According to Cranz,f who lived 
 for a long time with the Esquimaux, " the natives believe 
 that ingenuity and dexterity in seal-catching (their highest 
 art and virtue) is hereditary; there is really something in 
 it, for the son of a celebrated seal-catcher will distinguish 
 himself, though he lost his father in childhood." But in 
 this case it is mental aptitude, quite as much as bodily 
 structure, Avhich appears to be inherited. It is asserted 
 that the hands of English laborers are at birth larger than 
 those of the gentry. J From the correlation which exists, 
 at least in some cases, between the development of the ex- 
 tremities and of the jaws, it is possible that in those classes 
 which do not labor much with their hands and feet, the 
 jaws would be reduced in size from this cause. That they 
 are generally smaller in refined and civilized men than in 
 hard-working men or savages, is certain. But with savages, 
 as Mr. Herbert Spencer || has remarked, the greater use of 
 the jaws in chewing coarse, uncooked food, would act in a 
 direct manner on the masticatory muscles, and on the bones 
 to which they are attached. In infants, long before birth, 
 the skin on the soles of the feet is thicker than on any other 
 part of the body;! and it can hardly be doubted that this is 
 due to the inherited effects of pressure during a long series 
 of generations. 
 
 It is familiar to every one that watchmakers and engrav- 
 ers are liable to be short-sighted, while men living much 
 out of doors, and especially savages, are generally long- 
 
 * " Saugethiere von Paraguay," 1880, s. 4. 
 
 f" History of Greenland," Eng. translat., 1767, vol. i, p. 230. 
 
 i " Intermarriage." By Alex. Walker, 1838, p. 377. 
 
 " The Variation of Animals under Domestication," vol. i, p. 173. 
 
 | "Principles of Biology," vol. i, p. 455. 
 
 f Paget, " Lectures on Surgical Pathology," vol. ii, 1853, p. 209.
 
 38 THE DESCENT OF MAN. 
 
 sighted.* Short-sight and long-sight certainly tend to 
 be inherited, f The inferiority of Europeans, in comparison 
 with savages, in eyesight and in the other senses, is no 
 doubt the accumulated and transmitted effect of lessened 
 use during many generations ; for Kengger J states that he 
 has repeatedly observed Europeans, who had been brought 
 up and spent their whole lives with the wild Indians, who 
 nevertheless did not equal them in the sharpness of their 
 senses. The same naturalist observes that the cavities in 
 the skull for the reception of the several sense-organs are 
 larger in the American aborigines than in Europeans ; and 
 this probably indicates a corresponding difference in the 
 dimensions of the organs themselves. Blumenbach has 
 also remarked on the large size of the nasal cavities in the 
 skulls of the American aborigines, and connects this fact 
 with their remarkably acute power of smell. The Mon- 
 golians of the plains of Northern Asia, according to Pallas, 
 have wonderfully perfect senses; and Prichard believes that 
 the great breadth of their skulls across the zygomas follows 
 from their highly developed sense-organs. 
 
 The Quechua Indians inhabit the lofty plateaux of Peru; 
 and Alcide d'Orbigny states || that, from continually breath- 
 ing a highly rarefied atmosphere, they have acquired chests 
 and lungs of extraordinary dimensions. The cells, also, of 
 the lungs are larger and more numerous than in Europeans. 
 
 * It is a singular and unexpected fact that sailors are inferior to 
 landsmen in their mean distance of distinct vision. Dr. B. A. Gould 
 (" Sanitary Memoirs of the War of the Rebellion," 1869, p. 530), has 
 proved this to be the case ; and he accounts for it by the ordinary 
 range of vision in sailors being " restricted to the length of the vessel 
 and the height of the masts." 
 
 f " The Variation of Animals under Domestication," vol. i, p. 8. 
 
 $ " Saugethiere von Paraguay," s. 8, 10. I have had good oppor- 
 tunities for observing the extraordinary power of eyesight in the 
 Fuegians. See also Lawrence (" Lectures on Physiology," etc. , 1822, 
 p. 404) on this same subject. M. Qiraud-Teulon has recently col- 
 lected (" Revue des Cours Scientifiques," 1870, p. 625) a large and 
 valuable body of evidence proving that the cause of short-sight, 
 " O'est le trcvoatt assidu, de pres." 
 
 % Prichard, " Phys. Hist, of Mankind," on the authority of Blum- 
 enbach, vol. i, 1851, p. 311 ; for the statement by Pallas, vol. iv, 
 1844, p. 407. 
 
 I Quoted by Prichard, " Researches into the Phys. Hist, of Man- 
 kind," voL v, p. 468.
 
 MANNER OF DEVELOPMENT. 39 
 
 These observations have been doubted ; bat Mr. D. Forbes 
 carefully measured many Aymaras, an allied race, living at 
 the height of between 10,000 and 15,000 feet ; and he in- 
 forms me * that they differ conspicuously from the men of 
 all other races seen by him in the circumference and length 
 of their bodies. In his table of measurements, the stature 
 of each man is taken at 1,000, and the other measurements 
 are reduced to this standard. It is here seen that the ex- 
 tended arms of the Aymaras are shorter than those of 
 Europeans, and much shorter than those of Negroes. 
 The legs are likewise shorter ; and they present this 
 remarkable peculiarity, that in every Aymara measured, 
 the femur is actually shorter than the tibia. On an 
 average, the length of the femur to that of the tibia is as 
 211 to 252 ; while in two Europeans, measured at the same 
 time, the femora to the tibise were as 244 to 230 ; and in 
 three Negroes as 258 to 241. The humerus is likewise 
 shorter relatively to the forearm. This shortening of that 
 part of the limb which is nearest to the body, appears to 
 be, as suggested to me by Mr. Forbes, a case of compensa- 
 tion in relation with the greatly increased length of the 
 trunk. The Aymaras present some other singular points 
 of structure, for instance, the very small projection of the 
 heel. 
 
 These men are so thoroughly acclimatized to their cold 
 and lofty abode, that when formerly carried down by the 
 Spaniards to the low eastern plains, and when now tempted 
 down by high wages to the gold- washings, they suffer a 
 frightful rate of mortality. Nevertheless Mr. Forbes found 
 a few pure families which had survived during two genera- 
 tions : and he observed that they still inherited their char- 
 acteristic peculiarities. But it was manifest, even without 
 measurement, that these peculiarities had all decreased ; 
 and on measurement, their bodies were found not to be so 
 much elongated as those of the men on the high plateau ; 
 while their femora had become somewhat lengthened, as 
 had their tibiae, although in a less degree. The actual 
 measurements may be seen by consulting Mr. Forbes* 
 memoir. From these observations, there can, I think, be 
 no doubt that residence during many generations at a great 
 
 *Mr. Forbes' valuable paper is now published in the "Journal of 
 the Ethnological Soc. of London, "new series, vol. ii, 1870, p. 193.
 
 40 THE DESCENT OF MAN. 
 
 elevation tends, both directly and indirectly, to induce in- 
 herited modifications in the proportions of the body.* 
 
 Although man may not have been much modified during 
 the latter stages of his existence through the increased or 
 decreased use of parts, the facts now given show that his 
 liability in this respect has not been lost ; and we positively 
 know that the same law holds good with the lower animals. 
 Consequently we may infer that when at a remote epoch 
 the progenitors of man were in a transitional state, and 
 were changing from quadrupeds into bipeds, natural selec- 
 tion would probably have been greatly aided by the in- 
 herited effects of the increased or diminished use of the dif- 
 ferent parts of the body. 
 
 Arrests of Development. There is a difference between 
 arrested development and arrested growth, for parts in the 
 former state continue to grow while still retaining their 
 early condition. Various monstrosities come under this 
 head; and some, as a cleft-palate, are known to be occa- 
 sionally inherited. It will suffice for our purpose to refer 
 to the arrested brain-development of microcephalous idiots, 
 as described in Vogt's memoir, f Their skulls are smaller, 
 and the convolutions of the brain are less complex than in 
 normal men. The frontal sinus, or the projection over the 
 eye-brows, is largely developed, and the jaws are pro- 
 gnathous to an " effrayant " degree; so that these idiots 
 somewhat resemble the lower types of mankind. Their in- 
 telligence, and most of their mental faculties, are extremely 
 feeble. They cannot acquire the power of speech, and are 
 wholly incapable of prolonged attention, but are much 
 given to imitation. They are strong and remarkably ac- 
 tive, continually gambolling and jumping about, and mak- 
 ing grimaces. They often ascend stairs on all-fours; and 
 are curiously fond of climbing up furniture or trees. We 
 are thus reminded of the delight shown by almost all boys 
 in climbing trees; and this again reminds us how lambs 
 and kids, originally alpine animals, delight to frisk on any 
 hillock, however small. Idiots also resemble the lower 
 
 *Dr. Wilckens (" Landwirthschaft. Woclienblatt," No. 10, 1869) 
 has lately published an interesting Essay showing how domestic ani- 
 mals, which live in mountainous regions, have their frames modified. 
 
 f " Mernoire suT les Microcephales, " 1867, pp. 50, 125, 169, 171,
 
 MANNER OF DEVELOPMENT. 41 
 
 animals in some other respects; thus several cases are re- 
 corded of their carefully smelling every mouthful of food 
 before eating it. One idiot is described as often using his 
 mouth in aid of his hands while hunting for lice. They 
 are often filthy in their habits, and have no sense of de- 
 cency; and several cases have been published of their bodies 
 being remarkably hairy.* 
 
 Reversion. Many of the cases to be here given, might 
 have been introduced under the last heading. When a 
 structure is arrested in its development, but still continues 
 growing, until it closely resembles a corresponding struct- 
 ure in some lower and adult member of the same group, it 
 may in one sense be considered as a case of reversion. The 
 lower members in a group give us some idea how the com- 
 mon progenitor was probably constructed; and it is hardly 
 credible that a complex part, arrested at an early phase of 
 embryonic development, should go on growing so as ulti- 
 mately to perform its proper function, unless it had ac- 
 quired such power during some earlier state of existence, 
 when the present exceptional or arrested structure was 
 normal. The simple brain of a microcephalous idiot, in 
 as far as it resembles that of an ape, may in this sense be 
 said to offer a case of reversion, f There are other cases 
 
 * Prof. Laycock sums up the character of brute-like idiots by call- 
 ing them theroid ; "Journal of Mental Science," July, 1863. Dr. 
 Scott ("The Deaf and Dumb," 2d edit., 1870, p. 10) has often ob- 
 served the imbecile smelling their food. See> on this same subject, 
 and on the hairiness of idiots, Dr. Maudsley, "Body and Mind," 
 1870, pp. 46-51. Pinel has also given a striking case of hairiness in 
 an idiot. 
 
 f In my "Variation of Animals under Domestication" (vol. ii, p. 
 57), I attributed the not very rare cases of supernumerary mammae 
 in women to reversion. I was led to this as a probable conclusion, 
 by the additional mammae being generally placed symmetrically on 
 the breast; and more especially from one case, in which a single effi- 
 cient mammae occurred in the inguinal region of a woman, the daugh- 
 ter of another woman with supernumerary mammae. But I now find 
 (see, for instance, Prof. Preyer, " Der Kampf um das Dasein," 1869, 
 s. 45) that mammae erraticce occur in other situations, as on the back, 
 in the armpit, and on the thigh; the mammae in this latter instance 
 having given so much milk that the child was thus nourished. The 
 probability that the additional mammae are due to reversion is thus 
 much weakened ; nevertheless, it still seems to me probable, because 
 two pairs are often found symmetrically on the breast ; and of this I 
 myself have received information in several cases. It is well known
 
 42 THE DESCENT OF MAN. 
 
 which come more strictly under our present head of rever- 
 sion. Certain structures, regularly occurring in the lower 
 members of the group to which man belongs, occasionally 
 make their appearance in him, though not found in the 
 normal human embryo ; or, if normally present in the 
 human embryo, they become abnormally developed, al- 
 though in a manner which is normal in the lower members 
 of the group. These remarks will be rendered clearer by 
 the following illustrations. 
 
 that some Lemurs normally have two pairs of mammae on the breast. 
 Five cases have been recorded of the presence of more than a pair of 
 mammae (of course rudimentary) in the male sex of mankind ; see 
 "Journal of Anat aiM Physiology," 1872, p. 56, for a case given by 
 Dr. Handyside, in which two brothers exhibited this peculiarity ; see 
 also a paper by Dr. Bartels, in " Reichert's and du Bois-Reymond's 
 Archiv.," 1872, p. 304. In one of the cases alluded to by Dr. Bartels, 
 a man bore five mammae, one being medial and placed above the 
 navel ; Meckel von Hernsbach thinks that this latter case is illus- 
 trated by a medial mammae occurring in certain Cheiroptera. On the 
 whole, we may well doubt if additional mammae would ever have 
 been developed in both sexes of mankind, had not his early progeni- 
 tors been provided with more than a single pair. In the above work 
 (vol. ii, p. 12), I also attributed, though with much hesitation, the 
 frequent cases of polydactylisin in men and various animals to rever- 
 sion. I was partly led to this through Prof. Owen's statement, that 
 some of the Ichthyopterygia possess more than five digits, and there- 
 fore, as I supposed, had retained a primordial condition ; but Prof. 
 Qegenbaur (" Jenaischen Zeitschrift," B. v, Heft. 3, s. 341), disputes 
 Owen's conclusion. On the other hand, according to the opinion 
 lately advanced by Dr. Giinther, on the paddle of Ceratodus, which 
 is provided with articulated bony rays on both sides of a central 
 chain of bones, there seems no great difficulty in admitting that six 
 or more digits on one side, or on both sides, might reappear through 
 reversion. I am informed by Dr. Zouteveen that there is a case on 
 record of a man having twenty-four fingers and twenty-four toes ! I 
 was chiefly led to the conclusion that the presence of supernumerary 
 digits might be due to reversion from the fact that such digits, not 
 only are strongly inherited, but, as I then believed, had the power of 
 regrowth after amputation, like the normal digits of the lower verte- 
 brata. But I have explained in the second edition of my Variation 
 under Domestication why I now place little reliance on the recorded 
 cases of such regrowth. Nevertheless it deserves notice, inasmuch 
 as arrested development and reversion are intimately related pro- 
 cesses ; that various structures in an embryonic or arrested condition, 
 such as a cleft palate, bifid uterus, etc., are frequently accompanied 
 by polydactylism. This has been strongly insisted on by Meckel and 
 Isidore Geoff roy St.-Hilaire. But at present it is the safest course to 
 give up altogether the idea that there is any relation between the de- 
 velopment of supernumerary digits and reversion to some lowly or- 
 ganized progenitor of man _
 
 MANNER OF DEVELOPMENT. 43 
 
 In various mammals the uterus graduates from a double 
 organ with two distinct orifices and two passages, as in the 
 marsupials, into a single organ, which is in no way double 
 except from having a slight internal fold, as in the higher 
 apes and man. The rodents exhibit a perfect series of gra- 
 dations between these two extreme states. In all mammals 
 the uterus is developed from two simple primitive tubes, 
 the inferior portions of which form the cornua; and it is, in 
 the words of Dr. Farre, "by the coalescence of the two 
 cornua at their lower extremities that the body of the uterus 
 is formed in man; while in those animals in which no mid- 
 dle portion or body exists, the cornua remain ununited. As 
 the development of the uterus proceeds, the two cornua be- 
 come gradually shorter, until at length they are lost, or, as 
 it were, absorbed into the body of the uterus." The angles 
 of the uterus are still produced into cornua, even in ani- 
 mals as high up in the scale as the lower apes and lemurs. 
 
 Now in women, anomalous cases are not very infrequent, 
 in which the mature uterus is furnished with cornua, or is 
 partially divided into two organs; and such cases, according 
 to Owen, repeat " the grade of concentrative development," 
 attained by certain rodents. Here perhaps we have an in- 
 stance of a' simple arrest of embryonic development, with 
 subsequent growth and perfect functional development; for 
 either side of the partially double uterus is capable of per- 
 forming the proper office of gestation. In other and rarer 
 cases, two distinct uterine cavities are formed, each having 
 its proper orifice and passage.* No such stage is passed 
 through during the ordinary development of the embryo ; 
 and it is difficult to believe, though perhaps not impossible, 
 that the two simple, minute, primitive tubes should know 
 how (if such an expression may be used) to grow into two 
 distinct uteri, each with a well-constructed orifice and pas- 
 sage, and each furnished with numerous muscles, nerves, 
 glands and vessels, if they had not formerly passed through 
 a similar course of development, as in the case of existing 
 marsupials. No one will pretend that so perfect a struct- 
 ure as the abnormal double uterus in woman could be the 
 result of mere chance. But the principal of reversion, by 
 
 * See Dr. A. Farre's well-known article in the " Cyclopaedia of 
 Anatomy and Physiology," vol. v, 1859, p. 642. Owen, "Anatomy 
 of Vertebrates," vol. iii, 1868, p. 687. Prof. Turner, in "Edinburgh 
 Medical Journal," Feb., Iggo-
 
 44 THE DESCENT OF MAN. 
 
 which a long-lost structure is called back into existence, 
 might serve as the guide for -its full development, even after 
 the lapse of an enormous interval of time. 
 
 Prof. Canestrini, after discussing the foregoing and 
 various analogous cases, arrives at the same conclusion as 
 that just given. He adduces another instance, in the case 
 of the malar bone,* which, in some of the Quadrumana 
 and other mammals, normally consists of two portions. 
 This is its condition in the human foetus when two months 
 old ; and through arrested development, it sometimes 
 remains thus in man when adult, more especially in the 
 lower prognathous races. Hence Canestrini concludes that 
 some ancient progenitor of man must have had this bone 
 normally divided into two portions, which afterward be- 
 came fused together. In man the frontal bone consists of 
 a single piece, but in the embryo, and in children, and in 
 almost all the lower mammals, it consists of two pieces 
 separated by a distinct suture. This suture occasionally 
 persists more or less distinctly in man after maturity ; and 
 more frequently in ancient than in recent crania, especially, 
 as Canestrini has observed, in those exhumed from the 
 Drift, and belonging to the brachycephalic type. Here 
 again he comes to the same conclusion as in the analogous 
 case of the malar bones. In this, and other instances 
 presently to be given, the cause of ancient races approach- 
 ing the lower animals in certain characters more frequently 
 than do the modern races, appears to be, that the latter 
 stand at a somewhat greater distance in the long line of 
 descent from their early semi-human progenitors. 
 
 *"Annuario della Soc. del Naturalisti in Modena," 1867, p. 83. 
 Prof. Canestrini gives extracts on this subject from various authori- 
 ties. Laurillard remarks, that as he has found a complete similarity 
 in the form, proportions, and connection of the two malar bones in 
 several human subjects and in certain apes, he cannot consider tins' 
 disposition of the parts as simply accidental. Another paper on this 
 same anomaly has been published by Dr. Saviotti in the " Gazzetta 
 delle Cliniche," Turin, 1871, where he says that traces of the division 
 may be detected in about two per cent, of adult skulls; he also re- 
 marks that it more frequently occurs in prognathous skulls, not of 
 the Aryan race, than in others. See also G. Delorenzi on the same 
 subject ; " Tre nuovi casi d'anomalia dell' osso malare," Torino, 1872. 
 Also, E. Morselli, " Sopra una rara anomalia dell' osso malare," 
 Modena, 1872. Still more recently Grnber has written a pamphlet 
 on the division of this bone. I give these references because a re- 
 viewer, without any grounds or scruples, has thrown doubts on my 
 statements.
 
 MANNER OF DEVELOPMENT. 45 
 
 Various other anomalies in man, more or less analogous 
 to the foregoing, have been advanced by different authors, 
 as cases of reversion ; but these seem not a little doubtful, 
 for we have to descend extremely low in the mammalian 
 series, before we find such structures normally present.* 
 
 In man, the canine teeth are perfectly efficient instruments 
 for mastication. But their true canine character, as Owenf 
 remarks, " is indicated by the conical form of the crown, 
 which terminates in an obtuse point, is convex outward 
 and flat or sub-concave within, at the base of which surface 
 there is a feeble prominence. The conical form is best ex- 
 pressed in the Melanian races, especially the Australian. 
 " The canine is more deeply implanted, and by a stronger 
 fang than the incisors." Nevertheless, this tooth no longer 
 serves man as a special weapon for tearing his enemies or 
 prey; it may, therefore, as far as its proper function is con- 
 cerned, be considered as rudimentary. In every large col- 
 lection of human skulls some may be found, as HackelJ 
 observes, with the canine teeth projecting considerably be- 
 yond the others in the same manner as in the anthropomor- 
 phous apes, but in a less degree. In these cases, open 
 spaces between the teeth in the one jaw are left for the re- 
 ception of the canines of the opposite jaw. An interspace 
 of this kind in a Kaffir skull, figured by Wagner, is sur- 
 prisingly wide. Considering how few are the ancient 
 skulls which have been examined, compared to recent 
 skulls, it is an interesting fact that in at least three cases 
 
 * A whole series of cases is given by Isid. Geoffrey St.-Hilaire, 
 " Hist, des Anomalies," torn, iii, p. 437. A reviewer (" Journal of 
 Anat. and Physiology," 1871, p. 366) blames me much for not having 
 discussed the numerous cases, which have been recorded, of various 
 parts arrested in their development. He says that, according to my 
 theory, " every transient condition of an organ, during its develop- 
 ment, is not only a means to an end, but once was an end in itself." 
 This does not seem to me necessarily to hold good. Why should not 
 variation occur during an early period of development, having no 
 relation to reversion ; yet such variations might be preserved and ac- 
 cumulated, if in any way serviceable, for instance, in shortening and 
 simplifying the course of development? And again, why should not 
 injurious abnormalities, such as atrophied or hypertrophied parts, 
 which have no relation to a former state of existence, occur at an 
 early period, as well as during maturity? 
 
 f "Anatomy of Vertebrates," vol. iii, 1868, p. 323. 
 
 % " Generelle Morphologic," 1866, B. ii, s. civ. 
 
 Carl Vogt's "Lectures on Man," Eng. translat., 1864, p. 151.
 
 46 THE DESCENT OF MAN. 
 
 the canines project largely ; and in the Naulette jaw they 
 are spoken of as enormous.* 
 
 Of the anthropomorphous 'apes the males alone have their 
 canines fully developed ; but in the female gorilla, and in 
 a less degree in the female orang, these teeth project con- 
 siderably beyond the others ; therefore the fact, of which I 
 have been assured, that women sometimes have considerably 
 projecting canines, is no serious objection to the belief that 
 their occasional great development in man is a case of re- 
 version to an ape-like progenitor. He who rejects with 
 scorn the belief that the shape of his own canines, and their 
 occasional great development in other men, are due to our 
 early forefathers having been provided with these formidable 
 weapons, will probably reveal, by sneering, the line of his 
 descent. For though he no longer intends, nor has the 
 power, to use these teeth as weapons, he will unconsciously 
 retract his " snarling muscles " (thus named by Sir 0. Bell),f 
 so as to expose them ready for action, like a dog prepared 
 to fight. 
 
 Many muscles are occasionally developed in man, which 
 are proper to the Quadrumana or other mammals. Prof. 
 VlacovichJ examined forty male subjects, and found a mus- 
 cle, called by him the ischio-pubic, in nineteen of them; in 
 three others there was a ligament which represented this 
 muscle; and in the remaining eighteen no trace of it. In 
 only two out of thirty female subjects was this muscle de- 
 veloped on both sides, but in three others the rudimentary 
 ligament was present. This muscle, therefore, appears to 
 be much more common in the male than in the female sex; 
 and on the belief in the descent of man from some lower 
 form, the fact is intelligible; for it has been detected in 
 several of the lower animals, and in all of these it serves 
 exclusively to aid the male in the act of reproduction. 
 
 Mr. J. Wood, in his valuable series of papers, has mi- 
 
 *C. Carter Blake, on a jaw from La Naulette, " Anthropolog. 
 Review," 1867, p. 295. Schaaffhausen, ibid., 1868, p. 426. 
 
 f " The Anatomy of Expression," 1844, pp. 110, 181. 
 
 J Quoted by Prof. Canestrini in the " Annuario," etc., 1867, p. 90. 
 
 These papers deserve careful study by any one who desires to 
 learn how frequently our muscles vary, and in varying come to re- 
 semble those of the Quadrumana. The following references relate 
 to the few points touched on in my text : "Proc. Royal Soc.," voL 
 xiv, 1865, pp. 379-384 ; vol. xv, 1866, pp. 241, 242 ; vol. xv, 1867, p. 
 544 ; vol. xvi, 1868, p. 524. I may here add that Dr. Murie and Mr
 
 MANNER OF DEVELOPMENT. 47 
 
 nutely described a vast number of muscular variations in 
 man, which resemble normal structures in the lower ani- 
 mals. The muscles which closely resemble those regularly 
 present in our nearest allies, the Quadrumana, are too 
 numerous to be here even specified. In a single male sub- 
 ject, having a strong bodily frame, and well-formed skull, 
 no less than seven muscular variations were observed, all of 
 which plainly represented muscles proper to various kinds 
 of apes. This man, for instance, had on both sides of his 
 neck a true and powerful " levator claviculce," such as is 
 found in all kinds of apes, and which is said to occur in 
 about one out of sixty human subjects.* Again, this man 
 had "a special abductor of the metatarsal bone of the fifth 
 digit, such as Prof. Huxley and Mr. Flower have shown to 
 exist uniformly in the higher and lower apes." I will give 
 only two additional cases; the acromio-basilar muscle is 
 found in all mammals below man, and seems to be correl- 
 ated with a quadrupedal gait,f and it occurs in about one 
 out of sixty human subjects. In the lower extremities Mr. 
 Bradley^ found an abductor ossis metatarsi quinti in both 
 feet of "man; this muscle had not up to that time been re- 
 corded in mankind, but is always present in the anthropo- 
 morphous apes. The muscles of the hands and arms parts 
 which are so eminently characteristic of man are extremely 
 liable to vary, so as to resemble the corresponding muscles 
 in the lower animals. Such resemblances are either perfect 
 or imperfect; yet in the latter case they are manifestly of a 
 transitional nature. Certain variations are more common 
 in man, and others in woman, without our being able to 
 assign any reason. Mr. Wood, after describing numerous 
 
 St. George Mivart have shown in their Memoir on the Lemuroidea 
 ("Transact. Zoolog. Soc.," vol. vii, 1869, p. 96), how extraordinarily 
 variable some of the muscles are in these animals, the lowest 
 members of the Primates. Gradations, also, in the muscles leading 
 to structures found in animals still lower in the scale, are numerous 
 In the Lemuroidea. 
 
 *See also Prof. Macalister in "Proc. R. Irish Academy," vol x, 
 1868, p. 124. 
 
 fMr. Champneys in "Journal of Anat. and Phys.," November. 
 1871, p. 178. 
 
 \ " Journal of Anat. and Phys.," May, 1872, p. 421, 
 
 Prof. Macalister (ibid., p. 121) has tabulated his observations, 
 and finds that muscular abnormalities are most frequent in the fore- 
 arms, secondly, in the face, thirdly, in the foot, etc.
 
 48 THE DESCENT OF MAN. 
 
 variations, makes the following pregnant remark: "Notable 
 departures from the ordinary type of the muscular struct- 
 ures run in grooves or directions, which must be taken to 
 indicate some unknown factor, of much importance to a 
 comprehensive knowledge of general and scientific an- 
 atomy."* 
 
 That this unknown factor is reversion to a former state 
 of existence may be admitted as in the highest degree 
 probable, f It is quite incredible that a man should through 
 mere accident abnormally resemble certain apes in no less 
 than seven of his muscles, if there had been no genetic con- 
 nection between them. On the other hand, if man is de- 
 scended from some ape-like creature, no valid reason can 
 be assigned why certain muscles should not suddenly reap- 
 pear after an interval of many thousand generations, in the 
 same manner as with horses, asses, and mules, dark col- 
 ored stripes suddenly reappear on the legs, and shoulders, 
 after an interval of hundreds, or more probably of thous- 
 ands of generations. 
 
 These various cases of reversion are so closely related to 
 those of rudimentary organs given in the first chapter, that 
 many of them might have been indifferently introduced either 
 there or here. Thus a human uterus furnished with cornua 
 
 *The Rev. Dr. Haughton, after giving ("Proc. R. Irish Academy," 
 June 27, 1864, p. 715) a remarkable case of variation in the human 
 flexor pollicis longm, adds : ' ' This remarkable example shows that 
 man may sometimes possess the arrangement of tendons of thumb 
 and fingers characteristic of the macaque ; but whether such a case 
 should be regarded as a macaque passing upward into a man, or a 
 man passing downward into a macaque, or as a congenital freak of 
 nature, I cannot undertake to say." It is satisfactory to hear so 
 capable an anatomist, and so embittered an opponent of evolutionism, 
 admitting even the possibility of either of his first propositions. 
 Prof. Macalister has also described (" Proc. R. Irish Acad.," vol. x, 
 1864, p. 138) variations in the flexor pollicis longus, remarkable from 
 their relations to the same muscle in the Quadrumana. 
 
 f Since the first edition of this book appeared, Mr. Wood has pub 
 lished another memoir in the "Phil. Transactions," 1870, p. 8!5, on 
 the varieties of the muscles of the human neck, shoulder, and chest. 
 He here shows how extremely variable these muscles are, and how 
 often and how closely the variations resemble the normal muscles of 
 thfa lower animals. He sums up by remarking: " It will be enough 
 for my purpose if I have succeeded in showing the more important 
 forms which, when occurring as varieties in the human subject, tend 
 to exhibit in a sufficiently marked manner what may be considered as 
 proofs and examples of the Darwinian principle of reversion, or law 
 of inheritance, in this department of anatomical science."
 
 MANNER OF DEVELOPMENT. 49 
 
 may be said to represent, in a rudimentary condition, the 
 same organ in its normal state in certain mammals. Some 
 parts which are rudimentary in man, as the os coccyx in 
 both sexes, and the mammge in the male sex, are always 
 present; while others, such as the supra-condyloid foramen, 
 only occasionally appear, and therefore might have been in- 
 troduced under the head of reversion. These several rever- 
 sionary structures, as well as the strictly rudimentary ones, 
 reveal the descent of man from some lower form in an 
 unmistakable manner. 
 
 Correlated Variation. In man, as in the lower ani- 
 mals, many structures are so intimately related, that when 
 one part varies so does another, without our being able, in 
 most cases, to assign any reason. We cannot say whether 
 the one part governs the other, or whether both are gov- 
 erned by some earlier developed part. Various monstrosi- 
 ties, as I. Geoffroy repeatedly insists t are thus intimately 
 connected. Homologous structures are particularly liable to 
 change together, as we see on the opposite sides of the body, 
 and in the upper and lower extremities. Meckel long ago 
 remarked, that when the muscles of the arm depart from 
 their proper type, they almost always imitate those of the 
 leg; and so, conversely, with the muscles of the legs. The 
 organs of sight and hearing, the teeth and hair, the color 
 of the skin and of the hair, color and constitution, are 
 more or less correlated.* Prof. Schaaffhausen first drew 
 attention to the relation apparently existing between a mus- 
 cular frame and the strongly pronounced supra-orbital 
 ridges, which are so characteristic of the lower races oi man. 
 
 Besides the variations which can be grouped with more 
 or less probability under the foregoing heads, there is a 
 large class of variations which may be provisionally called 
 spontaneous, for to our ignorance, they appear to arise 
 without any exciting cause. It can, however, be shown 
 that such variations, whether consisting of slight individ- 
 ual differences, or of strongly marked and abrupt devi- 
 ations of structure, depend much more on the constitu- 
 tion of the organism than on the n-ature of the conditions 
 to which it has been subjected, f 
 
 *The authorities for these several statements are given in my 
 "Variation of Animals under Domestication," vol. ii, pp. 320-335. 
 
 fThis whole subject has been discussed in chap, xxiii, vol. ii, of 
 my " Variation of Animals and Plants under Domestication."
 
 50 THE DESCENT OF MAN. 
 
 Mate of Increase. Civilized populations have been 
 known under favorable conditions, as in the United States, 
 to double their numbers in twenty-five years ; and, accord- 
 ing to a calculation, by Euler, this might occur in a little 
 over twelve years.* At the former rate, the present popu- 
 lation of the United States (thirty millions), would in 657 
 years cover the whole terraqueous globe so thickly, that 
 four men would have to stand on each square yard of sur- 
 face. The primary or fundamental check to the continued 
 increase of man is the difficulty of gaining subsistence, and 
 of living in comfort. We may infer that this is the case 
 from what we see, for instance, in the United States, 
 where subsistence is easy, and there is plenty of room. If 
 such means were suddenly doubled in Great Britain, our 
 number would be quickly doubled. With civilized nations 
 this primary check acts chiefly by restraining marriages. 
 The greater death-rate of infants in the poorest classes is 
 also very important; as well as the greater mortality, from 
 various diseases, of the inhabitants of crowded and miser- 
 able houses at all ages. The effects of severe epidemics 
 and wars are soon counterbalanced, and more than counter- 
 balanced in nations placed under favorable conditions. 
 Emigration also comes in aid as a temporary check, but 
 with the extremely poor classes, not to any great extent. 
 
 There is reason to suspect, as Malthus has remarked, that 
 the reproductive power is actually less in barbarous, 
 than in civilized races. We know nothing positively 
 on this head, for with savages no census has been taken ; 
 but from the concurrent testimony of missionaries, and of 
 others who have long resided with such people, it appears 
 that their families are usually small, and large ones rare. 
 This may be partly accounted for, as it is believed, by the 
 women suckling their infants during a long time ; but it 
 is highly probable that savages, who often suffer much 
 hardship, and who do not obtain so much nutritious food 
 as civilized men, would be actually less prolific. I have 
 shown in a former work,f that all our domesticated quad- 
 rupeds and birds, and all our cultivated plants, are more 
 fertile than the corresponding species in a state of nature. 
 
 * Bee the ever memorable " Essay on the Principle of Population," 
 by the Rev. T. Malthus, vol. i, 1826, pp. 6, 517. 
 
 f " Variation of Animals and Plants under Domestication," vol. ii, 
 pp. 111-113, 163.
 
 MANNER OF DEVELOPMENT. 51 
 
 It is no valid objection to this conclusion that animals sud- 
 denly supplied with an excess of food, or when grown very 
 fat, and that most plants on sudden removal from very 
 poor to very rich soil, are rendered more or less sterile. We 
 might, therefore, expect that civilized men, who in one 
 sense are highly domesticated, would be more prolific than 
 wild men. It is also probable that the increased fertility of 
 civilized nations would become, as with our domestic 
 animals, an inherited character : it is at least known that 
 with mankind a tendency to produce twins runs in families.* 
 Notwithstanding that savages appear to be less prolific 
 than civilized people, they would no doubt rapidly increase 
 if their numbers were not by some means rigidly kept down. 
 The Santali, or hill-tribes of India, have recently afforded 
 a good illustration of this fact ; for, as shown by Mr. 
 Hunter, f they have increased at an extraordinary rate since 
 vaccination has been introduced, other pestilences mitigated, 
 and war sternly repressed. This increase, however, would 
 not have been possible had not these rude people spread 
 into the adjoining districts, and worked for hire. Savages 
 almost always marry ; yet there is some prudential restraint, 
 for they do not commonly marry at the earliest possible age. 
 The young men are often required to show that they can 
 support a wife ; and they generally have first to earn the 
 price with which to purchase her from her parents. With 
 savages the difficulty of obtaining subsistence occasionally 
 limits their number in a much more direct manner than 
 with civilized people, for all tribes periodically suffer from 
 severe famines. At such times savages are forced to devour 
 much bad food, and their health can hardly fail to be 
 injured. Many accounts have been published of their pro- 
 truding stomachs and emaciated limbs after and during 
 famines. They are then, also, compelled to wander much, 
 and, as I was assured in Australia, their infants perish in 
 large numbers. As famines are periodical, depending 
 chiefly on extreme seasons, all tribes must fluctuate in 
 number. They cannot steadily and regularly increase, as 
 there is no artificial increase in the supply of food. Sav- 
 ages, when hard pressed, encroach on each other's terri- 
 tories, and war is the result ; but they are indeed almost 
 
 *Mr. Sedgwick, "British and Foreign Medico-Chirurg. Eeview," 
 July, 1863, p. 170. 
 f " The Annals of Rural Bengal," by W. W. Hunter, 1868, p. 259.
 
 52 THE DESCENT OF MAN. 
 
 always at war with their neighbors. They are liable to 
 many accidents on land and water in their search for food ; 
 and in some countries they suffer much from the larger 
 beasts of prey. Even in India, districts have been depop- 
 ulated by the ravages of tigers. 
 
 Malthus has discussed these several checks, but he does 
 not lay stress enough on what is probably the most import- 
 ant of all, namely, infanticide, especially of female infants, 
 and the habit of procuring abortion. These practices now 
 
 Ere vail in many quarters of the world; and infanticide seems 
 mnerly to have prevailed, as Mr. M'Lennan* has shown, 
 on a still more extensive scale. These practices appear to 
 have originated in savages recognizing the difficulty, or 
 rather the impossibility of supporting all the infants that 
 are born. Licentiousness may also be added to the forego- 
 ing checks; but this does not follow from failing means of 
 subsistence; though there is reason to believe that in some 
 cases (as in Japan) it has been intentionally encouraged as 
 a means of keeping down the population. 
 
 If we look back to an extremely remote epoch, before 
 man had arrived at the dignity of manhood, he would have 
 been guided more by instinct and less by reason than are 
 the lowest savages at the present time. Our early semi- 
 human progenitors would not have practiced infanticide or 
 polyandry; for the instincts of the lower animals are never 
 so perverted f as to lead them regularly to destroy their own 
 offspring, or to be quite devoid of jealousy. There would 
 have been no prudential restraint from marriage, and the 
 sexes would have freely united at an early age. Hence the 
 progenitors of man would have tended to increase rapidly; 
 
 * " Primitive Marriage," 1865. 
 
 f A writer in the " Spectator " (March 12, 1871, p. 320) comments 
 as follows on this passage: "Mr. Darwin finds himself compelled to 
 reintroduce a new doctrine of the fall of man. He shows that the 
 instincts of the higher animals are far nobler than the habits of sav- 
 age races of men, and he finds himself, therefore, compelled to re- 
 introduce in a form of the substantial orthodoxy of which he 
 appears to be quite unconscious and to introduce as a scientific 
 hypothesis the doctrine that man's gain of knowledge was the cause 
 of a temporary but long-enduring moral deterioration, as indicated by 
 the many foul customs, especially as to marriage, of savage tribes. 
 What does the Jewish tradition of the moral degeneration of man 
 through his snatching at a knowledge forbidden him by his highest 
 instinct assert beyond this t "
 
 s 
 
 MANNER OF DEVELOPMENT. 53 
 
 but checks of some kind, either periodical or constant, must 
 have kept down their numbers, even more severely than 
 with existing savages. What the precise nature of these 
 checks were we cannot say, any more than with most other 
 animals. We know that horses and cattle, which are not 
 extremely prolific animals, when first turned loose in South 
 America, increased at an enormous rate. The elephant, 
 the slowest breeder of all known animals, would in a few 
 thousand years stock the whole world. The increase of 
 every species of monkey must be checked by some means; 
 but not, as Brehm remarks, by the attacks of beasts of 
 >rey. No one will assume that the actual power of repro- 
 uction in the wild horses and cattle of America, was at 
 first in any sensible degree increased; or that, as each dis- 
 trict became fully stocked, this same power was diminished. 
 No doubt in this case, and in all others, many checks con- 
 cur, and different checks under different circumstances; 
 periodical dearths, depending on unfavorable seasons, being 
 probably the most important of all. So it will have been 
 with the early progenitors of man. 
 
 Natural Selection. We have now seen that man is vari- 
 able in body and mind; and that the variations are induced, 
 either directly or indirectly, by the same general causes, 
 and obey the same general laws, as with the lower animals. 
 Man has spread widely over the face of the earth, and must 
 have been exposed, during his incessant migrations,* to the 
 most diversified conditions. The inhabitants of Tierra del 
 Fuego, the Cape of Good Hope, and Tasmania in the one 
 hemisphere, and of the Arctic regions in the other, must 
 have passed through many climates, and changed their 
 habits many times, before they reached their present homes, f 
 The early progenitors of man must also have tended, like 
 all other animals, to have increased beyond their means of 
 subsistence; they must, therefore, occasionally have been 
 exposed to a struggle for existence, and consequently to the 
 rigid law of natural selection. Beneficial variations of all 
 kinds will thus, either occasionally or habitually, have been 
 preserved and injurious ones eliminated. I do not refer to 
 strongly marked deviations of structure, which occur only 
 
 * See some good remarks to this effect by W. Stanley Jevons, "A 
 Deduction from Darwin's Theory," " Nature," 1869, p. 231. 
 f Latham, "Man and his Migrations," 1851, p. 135.
 
 54 THE DESCENT OF MAN. 
 
 at long intervals of time, but to mere individual differences. 
 We know, for instance, that the muscles of our hands and 
 feet, which determine our powers of movement, are liable, 
 like those of the lower animals,* to incessant variability. 
 If then the progenitors of man inhabiting any district, es- 
 pecially one undergoing some change in its conditions, were 
 divided into two equal bodies, the one-half which included 
 all the individuals best adapted by their powers of move- 
 ment for gaining subsistence, or for defending themselves, 
 would on an average survive in greater numbers, and pro- 
 create more offspring than the other and less well endowed 
 half. 
 
 Man in the rudest state in which he now exists is the 
 most dominant animal that has ever appeared on this earth. 
 He has spread more widely than any other highly organized 
 form: and all others have yielded before him. He mani- 
 festly owes this immense superiority to his intellectual fac- 
 ulties, to his social habits, which lead him to aid and defend 
 his fellows, and to his corporeal structure. The supreme 
 Importance of these characters has been proved by the final 
 arbitrament of the battle for life. Through his powers of 
 intellect, articulate language has been evolved; and on this 
 his wonderful advancement has mainly depended. As Mr. 
 Chauncey Wright remarks :f""* f a psychological analysis of 
 the faculty of language shows, that even the smallest pro- 
 ficiency in it might require more brain power than the 
 greatest proficiency in any other direction." He has in- 
 vented and is able to use various weapons, tools, traps, etc., 
 with which he defends himself, kills or catches prey, and 
 otherwise obtains food. He has made rafts or canoes for 
 fishing or crossing over to neighboring fertile islands. He 
 has discovered the art of making fire, by which hard and 
 stringy roots can be rendered digestible, and poisonous roots 
 or herbs innocuous. This discovery of fire, probably the 
 greatest ever made by man, excepting language, dates from 
 before the dawn of history. These several inventions, by 
 
 * Messrs. Murie and Mivart in their " Anatomy of the Lemuroidea " 
 ("Transact. Zoolog. Soc.," vol. vii, 1869, pp. 96-98) say, "some 
 muscles are so irregular in their distribution that they cannot be well 
 classed in any of the above groups." These muscles differ even on 
 the opposite sides of the same individual. 
 
 f Limits of Natural Selection, "North American Review," Oct. 
 1870, p. S95.
 
 MANNER OP DEVELOPMENT. 55 
 
 which, man in the rudest state has become so pre-eminent, 
 are the direct results of the development of his powers of 
 observation, memory, curiosity, imagination, and reason. I 
 cannot, therefore, understand how it is that Mr. Wallace* 
 maintains, that " natural selection could only have endowed 
 the savage with a brain a little superior to that of an ape." 
 
 Although the intellectual powers and social habits of 
 man are of paramount importance to him, we must not un- 
 derrate the importance of his bodily structure, to which 
 subject the remainder of this chapter will be devoted; the 
 development of the intellectual and social or moral facul- 
 ties being discussed in a later chapter. 
 
 Even to hammer with precision is no easy matter, as 
 every one who has tried to learn carpentry will admit. To 
 throw a stone with as true an aim as a Fuegian in defend- 
 ing himself, or in killing birds, requires the most consum- 
 mate perfection in the correlated action of the muscles of 
 the hand, arm, and shoulder, and, further, a fine sense of 
 touch. In throwing a stone or spear, and in many other 
 actions, a man must stand firmly on his feet; and this again 
 demands the perfect co-adaptation of numerous muscles. 
 To chip a flint into the rudest tool, or to form a barbed 
 spear or hook from a bone, demands the use of a perfect 
 hand; for, as a most capable judge, Mr. Schoolcraft,f re- 
 marks, the shaping fragments of stone into knives, lances, 
 or arrow-heads, shows ''extraordinary ability and long 
 
 * " Quarterly Review," April, 1869, p. 392. This subject is more 
 fully discussed in Mr. Wallace's " Contributions to the Theory of 
 Natural Selection," 1870, in which all the essays referred to in this 
 work are republished. The " Essay on Man," has been ably criti- 
 cized by Prof. Claparede, one of the most distinguished zoologists in 
 Europe, in an article published in the " Bibliotheque Universelle," 
 June, 1870. The remark quoted in my text will surprise every one 
 who has read Mr. Wallace's celebrated paper on ' ' The Origin of 
 Human Races deduced from the Theory of Natural Selection," orig- 
 inally published in the "Anthropological Review," May, 1864, p. 
 clviii. I cannot here resist quoting a most just remark by Sir J. 
 Lubbock ("Prehistoric Times," 1865, p. 479) in reference to this 
 paper, namely, that Mr. Wallace, "with characteristic unselfishness, 
 ascribes it (i. e. the idea of natural selection) unreservedly to Mr. 
 Darwin, although, as is well known, he struck out the idea inde- 
 pendently, and published it, though not with the same elaboration, 
 at the same time." 
 
 f Quoted by Mr. Lawson Tait in his "Law of Natural Selection," 
 "Dublin Quarterly Journal of Medical Science," Feb., 1869. Dr. 
 Keller is likewise" quoted to the same effect.
 
 56 THE DESCENT Off MAN. 
 
 practice. " This is to a great extent proved by the fact that 
 primeval men practiced a division of labor ; each man did 
 not manufacture his own flint tools or rude pottery, but 
 certain individuals appear to have devoted themselves to 
 such work, no doubt receiving in exchange the produce of 
 the chase. Archaeologists are convinced that an enormous 
 interval of time elapsed before our ancestors thought of 
 grinding chipped flints into smooth tools. One can hardly 
 doubt, that a man-like animal who possessed a hand and 
 arm sufficiently perfect to throw a stone with precision, 01 
 to form a flint into a rude tool, could, with sufficient prac- 
 tice, as far as mechanical skill alone is concerned, make 
 almost any thing which a civilized man can make. The 
 structure of the hand in this respect may be compared with 
 that of the vocal organs, which in the apes are used for 
 uttering various signal-cries, or, as in one genus, musical 
 cadences; but in man the closely similar vocal organs 
 have become adapted through the inherited effects of 
 use for the utterance of articulate language. 
 
 Turning now to the nearest allies of men, and therefore 
 to the best representatives of our early progenitors, we find 
 that the hands of the Quadrumana are constructed on the 
 same general pattern as our own, but are far less perfectly 
 adapted for diversified uses. Their hands do not serve for 
 locomotion so well as the feet of a dog; as may be seen in 
 such monkeys as the chimpanzee and orang, which walk on 
 the outer margins of the palms, or on the knuckles.* 
 Their hands, however, are admirably adapted for climbing 
 trees. Monkeys seize thin branches or ropes, with the 
 thumb on one side and the fingers and palm on the other, 
 in the same manner as we do. They can thus also lift 
 rather large objects, such as the neck of a bottle, to their 
 mouths. Baboons turn over stones, and scratch up roots 
 with their hands. They seize nuts, insects, or other small 
 objects with the thumb in opposition to the fingers, and no 
 doubt they thus extract eggs and the young from the nests 
 of birds. American monkeys beat the wild oranges on the 
 branches until the rind is cracked, and then tear it off with 
 the fingers of the two hands. In a wild state they break 
 open hard fruits with stones. Other monkeys open mussel- 
 enells with the two thumbs. With their fingers they pull 
 
 *0wen, " Anatomy of Vertebrates," vol. iii, p. 71.
 
 MANNER OF DEVELOPMENT. 57 
 
 out thorns and burrs, and hunt for each other's parasites. 
 They roll down stones, or throw them at their enemies: 
 nevertheless, they are clumsy in these various actions, and, 
 as I have myself seen, are quite unable to throw a stone 
 with precision. 
 
 It seems to me far from true that because ( ' objects are 
 grasped clumsily" by monkeys, "a much less specialized 
 organ of prehension " would have served them* equally well 
 with their present hands. On the contrary, I see no reason 
 to doubt that more perfectly constructed hands would have 
 been an advantage to them, provided that they were not 
 thus rendered less fitted f or x climbing trees. We may sus- 
 pect that a hand as perfect as that of man would have been 
 disadvantageous for climbing; for the most arboreal mon- 
 keys in the world, namely, Ateles, in America, Oolobus, in 
 Africa, and Hylobates, in Asia, are either thumbless, or 
 their toes partially cohere, so that their limbs are converted 
 into mere grasping hooks, f 
 
 As soon as some ancient member in the great series of the 
 Primates came to be less arboreal, owing to a change in its 
 manner of procuring subsistence, or to some change in the 
 surrounding conditions, its habitual manner .of progression 
 would have been modified; and thus it would have been 
 rendered more strictly quadrupedal or bipedal. Baboons 
 frequent hilly and rocky districts, and only from necessity 
 climb high trees ; J and they have acquired almost the gait 
 of a dog. Man alone has become a biped; and we can, I 
 think, partly see how he has come to assume his erect atti- 
 tude, which forms one of his most conspicuous characters. 
 Man could not have attained his present dominant position 
 in the world Avithout the use of his hands, which are so 
 admirably adapted to act in obedience to his will. Sir C. 
 Bell insists that "the hand supplies all instruments, and 
 
 *" Quarterly Review," April, 1869, p. 392. 
 
 f In Hylobates syndactylus, as the name expresses, two of the toes 
 regularly cohere ; and this, as Mr. Blyth informs me, is occasionally 
 the case with the toes of H. agilis, lar, and leucisciis. Colobus is 
 strictly arboreal and extraordinarily active (Brehin, " Thierleben," 
 B. i, s. 50), but whether a better climber than the species of the 
 allied genera, I do not know. It deserves notice that the feet of the 
 sloths, the most arboreal animals in the world, are wonderfully 
 hook-like. 
 
 $ Brehm, "Thierleben," B. i, s. 80. 
 
 " The Hand," etc. " Bridgewater Treatise," 1833, p. 88.
 
 58 THE DESCENT OF MAN. 
 
 by its correspondence with the intellect gives him universal 
 dominion." But the hands and arms could hardly have 
 become perfect enough to ''have manufactured weapons, or 
 to have hurled stones and spears with a true aim, as long as 
 they were habitually used for locomotion and for supporting 
 the whole weight of the body, or, as before remarked, so 
 long as they were especially fitted for climbing trees. Such 
 rough treatment would also have blunted the sense of 
 touch, on which their delicate use largely depends. From 
 these causes alone it would have been an advantage to man 
 to become a biped,; but for many actions it is indispensable 
 that the arms and whole upper part of the body should be 
 free; and he must for this end stand firmly on his feet. To 
 gain this great advantage, the feet have been rendered flat; 
 and the great toe has been peculiarly modified, though this 
 has entailed the almost complete loss of its power of pre- 
 hension. It accords with the principle of the division of 
 physiological labor, prevailing throughout the animal 
 kingdom, that as the hands became perfected for prehen- 
 sion, the feet should have became perfected for support 
 and locomotion. With some savages, however, the foot 
 has not altogether lost its prehensile power, as shown by 
 their manner of climbing trees and of using them in other 
 ways.* 
 
 If it be an advantage to man to stand firmly on his feet 
 and to have his hands and arms free, of which, from his 
 pre-eminent success in the battle of life, there can be no 
 doubt, then I can see no reason why it should not have been 
 advantageous to the progenitors of man to have become more 
 and more erect or bipedal. They would thus have been 
 better able to defend themselves with stones or clubs, to 
 attack their prey, or otherwise to obtain food. The best 
 built individuals would in the long run have succeeded 
 best and have survived in larger numbers. If the gorilla 
 and a few allied forms had become extinct, it might have 
 been argued, with great force and apparent truth, that an 
 
 * HRckel has an excellent discussion on the steps by which man 
 became a biped: "Natiirliche Schopfungsgeschichte," 1868, s. 507. 
 Dr. Biichner ("Conferences sur la Th6orie Darwinienne," 1869, p. 
 185) has given good cases of the use of the foot as a prehensile organ 
 by man ; and has also written on the manner of progression of the 
 higher apes, to which I allude in the following paragraph ; see also 
 Owen (" Anatomy of Vertebrates," vol. iii, p. 71) on this latter 
 subject.
 
 MANNER OF DEVELOPMENT. k 59 
 
 animal could not have been gradually converted from a 
 quadruped into a biped, as all the individuals in an inter- 
 mediate condition would have been miserably ill-fitted for 
 progression. But we know (and this is well worthy of re- 
 flection) that the anthropomorphous apes are now actually 
 in an intermediate condition ; and no one doubts that they 
 are on the whole well adapted for their conditions of life. 
 Thus the gorilla runs with a sidelong shambling gait, but 
 more commonly progresses by resting on its bent hands. 
 The long-armed apes occasionally use their arms like 
 crutches, swinging their bodies forward between them, and 
 gome kinds of Hylobates, without having been taught, can 
 walk or run upright with tolerable quickness ; yet they 
 move awkwardly and much less securely than man. We 
 pee, in short, in existing monkeys a manner of progression 
 intermediate between that of a quadruped and a biped; 
 but, as an unprejudiced judge* insists, the anthropo- 
 morphous apes approach in structure more nearly to the 
 bipedal than to the quadrupedal type. 
 
 As the progenitors of man became more and more erect, 
 with their hands and arms more and more modified for 
 urehension and other purposes, with their feet and legs at 
 the same time transformed for firm support and progres- 
 sion, endless other changes of structure would have be- 
 come necessary. The pelvis would have to be broadened, 
 the spine peculiarly curved, and the head fixed m an 
 altered position, all of which changes have been attained 
 by man. Prof. Schaaffhausenf maintains that " the pow- 
 erful masicoia processes of the human skull are the result 
 of his erect position;" and these processes are absent in 
 the orang, chimpanzee, etc., and are smaller in the go- 
 rilla than in man. Various other structures, which appear 
 connected with man's erect position, might here have been 
 added. It is very difficult to decide how far these corre- 
 lated modifications are the result of natural selection, and 
 how far of the inherited effects of the increased use of cer- 
 tain, parts or of the action of one part on another. 
 
 * Prof. Broca, La Constitution des Vertebres caudales ; " La Revue 
 d' knthropologie," 1872, p. 26 (separate copy). 
 
 f " On the Primitive Form of the Skull," translated in " Anthrop- 
 ological Eeview,"Oct 1868, p. 438. Owen ("Anatomy of Verte- 
 brates," vol. ii, 1866, p. 551) on the ruastoid processes in the higher 
 apes.
 
 60 THE DESCENT OF MAN. 
 
 No doubt these means of change often co-operate; 
 when certain muscles, and the crests of bone to which 
 they are attached, become enlarged by habitual use, this 
 shows that certain actions are habitually performed and 
 must be serviceable. Hence the individuals which per- 
 formed them best would tend to survive in greater numbers- 
 
 The free use of the arms and hands, partly the cause 
 and partly the result of man's erect position, appears to 
 have led in an indirect manner to other modifications of 
 structure. The early male forefathers of man were, as 
 previously stated, probably furnished with great canine 
 teeth; but as they gradually acquired the habit of using 
 stones, clubs, or other weapons for fighting with their 
 enemies or rivals they would use their jaws and teeth less 
 and less. In this case the jaws, together with the teeth, 
 would become reduced in size, as we may feel almost sure 
 from innumerable analogous cases. In a future chapter 
 we shall meet Avith a closely parallel case in the reduction 
 or complete disappearance of the canine teeth in male 
 ruminants, apparently in relation with the development of 
 their horns; and in horses in relation to their habits of 
 fighting with their incisor teeth and hoofs. 
 
 In the adult male anthropomorphous apes, as Riiti- 
 meyer* and others have insisted, it is the effect on the 
 skull of the great development of the jaw-muscles that causes 
 it to differ so greatly in many respects from that of man, 
 and has given to these animals " a truly frightful physi- 
 ognomy." Therefore, as the jaws and teeth in man's pro- 
 genitors gradually become reduced in size, the adult skull 
 would have come to resemble more and more that of exist- 
 ing man. As we shall hereafter see, a great reduction of 
 the canine teeth in the males would almost certainly affect 
 the teeth of the females through inheritance. 
 
 As the various mental faculties gradually developed 
 themselves the brain would almost certainly become larger. 
 No one, I presume, doubts that the la-'ge proportion which 
 the size of man's brain bears to his body, compared to the 
 same proportion in the gorilla or orang, is closely connected 
 with his higher mental powers. We meet with closely 
 analogous facts with insects, for in ants the cerebral gan- 
 glia are of extraordinary dimensions, and in all the Hyme- 
 
 *"Die Grenzen der Thierwelt, eine Betrachtung zu Darwin's 
 Lhre," 1868, s. 51.
 
 MANNER OF DEVELOPMENT. 61 
 
 noptera these ganglia are many times larger than in the 
 less intelligent orders, such as beetles.* On the other 
 hand, no one supposes that the intellect of any two ani- 
 mals or of any two men can be accurately gauged by the 
 cubic contents of their skulls. It is certain that there 
 may be extraordinary mental activity with an extremely 
 small absolute mass of nervous matter: thus the wonder- 
 fully diversified instincts, mental powers and affections of 
 ants are notorious, yet their cerebral ganglia are not so 
 large as the quarter of a small pin's head. Under this 
 point of view the brain of an ant is one of the most mar- 
 velous atoms of matter in the world, perhaps more so than 
 the brain of a man. 
 
 The belief that there exists in man some close relation 
 between the size of the brain and the development of the 
 intellectual faculties is supported by the comparison of the 
 skulls of savage and civilized races, of ancient and modern 
 people, and by the analogy of the whole vertebrate series. 
 Dr. J. Barnard Davis has proved, f by many careful meas- 
 urements, that the mean internal capacity of the skull in 
 Europeans is 92.3 cubic inches; in Americans 87.5; in 
 Asiatics 87.1; and in Australians only 81.9 cubic inches. 
 Professor Broca J found that the nineteenth century 
 skulls from graves in Paris were larger than those from 
 vaults of the twelfth century, in the proportion of 1484 to 
 1426; and that the increased size, as ascertained by meas- 
 urements, was exclusively in the frontal part of the skull 
 the seat of the intellectual faculties. Prichard is per- 
 suaded that the present inhabitants of Britain have 
 " much more capacious brain-cases " than the ancient in- 
 habitants. Nevertheless, it must be admitted that some 
 skulls of very high antiquity, such as the famous one of 
 Neanderthal, are well developed and capacious. With 
 
 *Dujardin, " Annales des Sc. Nat.," 3d series Zoolog. torn, xiv, 
 1850, p. 203. See also Mr. Lowne, " Anatomy and Phys. of the 
 Musca vomitoria," 1870, p. 14. My son, Mr. F. Darwin," dissected 
 for me the cerebral ganglia of the Formica rufa. 
 
 f " Philosophical Transactions," 1869, p. 513. 
 
 j " Les Selections," M. P. Broca, " Revue d'Anthropologies," 1873 ; 
 see also, as quoted in C. Vogt's " Lectures on Man," Eng. translat., 
 1864, pp. 88, 90. Prichard, Phys. Hist, of Mankind," vol. i, 1838, 
 p. 305. 
 
 In the interesting article just referred to, Prof. Broca has well 
 remarked, that in civilized nations*.the average capacity of the skull
 
 62 THE DESCENT OF MAN. 
 
 respect to the lower animals, M. E. Lartet,* by comparing 
 th crania of tertiary and recent mammals belonging to 
 the same groups, has come to the remarkable conclusion 
 that the brain is generally larger and the convolutions are 
 more complex in the more recent forms. On the other 
 hand, I have shown f that the brains of domestic rabbits 
 are considerably reduced in bulk, in comparison with those 
 of the wild rabbit or hare; and this may be attributed to 
 their having been closely confined during many genera- 
 tions, so that they have exerted their intellect, instincts, 
 senses and voluntary movements but little. 
 
 The gradually increasing weight of the brain and skull 
 in man must have influenced the development of the sup- 
 porting spinal column, more especially while he was becom- 
 ing erect. As this change of position was being brought 
 about, the internal pressure of the brain will also have in- 
 fluenced the form of the skull; for many facts show how 
 easily the skull is thus affected. Ethnologists believe that 
 it is modified by the kind of cradle in which infants sleep. 
 Habitual spasms of the muscles, and a cicatrix from a se- 
 vere burn, have permanently modified the facial bones. In 
 young persons whose heads have become fixed either side- 
 ways or backward, owing to disease, one of the two eyes 
 has changed its position, and the shape of the skull has 
 been altered apparently by the pressure of the brain in a 
 new direction.^ I have shown that with long-eared rabbits 
 
 must be lowered by the preservation of a considerable number of in- 
 dividuals, weak in mind and body, who would have been promptly 
 eliminated in the savage state. On the other hand, with savages, the 
 average includes only the more capable individuals, who have been 
 able to survive under extremely hard conditions of life. Broca thus 
 explains the otherwise inexplicable fact, that the mean capacity of 
 the skull of the ancient Troglodytes of Lozere is greater than that of 
 modern Frenchmen. 
 
 * " Comptes-rendus des Sciences," etc., June 1, 1868. 
 
 J"The Variation of Animals and Plants under Domestication," 
 . i, pp. 124-129. 
 
 J Schaaffhausen gives from Blumenbach and Busch, the cases of 
 the spasms and cicatrix, in " Anthropolog. Review," Oct. 1868, p. 
 420. Dr. Jarrold (" Anthropologia," 1808, pp. 115, 116) adduces from 
 Camper and from his own observations, cases of the modification of 
 the skull from the head being fixod in an unnatural position. He 
 believes that in certain trades, such as that of a shoemaker, where 
 the head is habitually held forward, the forehead becomes more 
 rounded and prominent.
 
 MANNER OF DEVELOPMENT. 63 
 
 even so trifling a cause as the lopping forward of one ear 
 drags forward almost every bone of the skull on that side; 
 so that the bones on the opposite side no longer strictly 
 correspond. Lastly, if any animal were to increase or 
 diminish much in general size, without any change in its 
 mental powers, or if the mental powers were to be much 
 increased or diminished, without any great change in the 
 size of the body, the shape of the skull would almost cer- 
 tainly be altered. I infer this from my observations on 
 domestic rabbits, some kinds of which have become very 
 much larger than the wild animal, while others have re- 
 tained nearly the same size, but in both cases the brain has 
 been much reduced relatively to the size of the body. Now 
 I was at first much surprised on finding that in all these 
 rabbits the skull had become elongated or dolichocephalic; 
 for instance, of two skulls of nearly equal breadth, the one 
 from a wild rabbit and the other from a large domestic 
 kind, the former was 3.15 and the latter 4.3 inches in 
 length.* One of the most marked distinctions in different 
 races of men is that the skull in some is elongated and in 
 others rounded ; and here the explanation suggested by the 
 case of the rabbits may hold good; for Welcker finds that 
 short " men incline more to brachycephaty, and tall men 
 to dolichocephaly;"f and tall men may be compared with 
 the larger and longer-bodied rabbits, all of which have 
 elongated skulls, or are dolichocephalic. 
 
 From these several facts we can understand, to a certain 
 extent, the means by which the great size and more or less 
 rounded form of the skull have been acquired by man; and 
 these are characters eminently distinctive of him in com- 
 parison with the lower animals. 
 
 Another most conspicuous difference between man and 
 the lower animals is the nakedness of his skin. "Whales 
 and porpoises (Cetacea), dugongs (Sirenia) and the hippo- 
 potamus are naked; and this may be advantageous to them 
 for gliding through the water; nor would it be injurious to 
 them from the loss of warmth, as the species which in- 
 habit the colder regions are protected by a thick layer of 
 blubber, serving the same purpose as the fur of seals and 
 
 *" Variation of Animals," etc., vol. i, p. 117, on the elongation of 
 tlie skull ; p. 119, on tlie effect of the lopping of one ear. 
 
 (Quoted by Schaaffhausen, in " Anthropolog. Review," Oct., 1868, 
 p. 419.
 
 64 THE DESCENT OF MAN. 
 
 otters. Elephants and rhinoceroses are almost hairless; 
 and as certain extinct species, which formerly lived under 
 an Arctic climate., were covered with long wool or hair, it 
 would almost appear as if the existing species of both 
 genera had lost their hairy covering from exposure to heat. 
 This appears the more probable, as the elephants in India 
 which live on elevated and cool districts are more hairy * 
 than those on the lowlands. May we then infer that man 
 became divested of hair from having aboriginally inhabited 
 some tropical land? That the hair is chiefly retained in 
 the male sex on the chest and face, and in both sexes at 
 the junction of all four limbs with the trunk, favors this 
 inference on the assumption that the hair was lost before 
 man became erect; for the parts which now retain most 
 hair would then have been most protected from the heat of 
 the sun. The crown of the head, however, offers a curious 
 exception, for at all times it must have been one of the 
 most exposed parts, yet is thickly clothed with hair. The 
 fact, however, that the other members of the order of 
 Primates, to which man belongs, although inhabiting 
 various hot regions, are well clothed with hair, generally 
 thickest on the upper surface, f is opposed to the supposi- 
 tion that man became naked through the action of the sun. 
 Mr. Belt believes J that within the tropics it is an advant- 
 age to man to be destitute of hair, as he is thus enabled to 
 free himself of the multitude of ticks (acari) and other 
 parasites, with which he is often infested, and which some- 
 times cause ulceration. But whether this evil is of suffi- 
 cient magnitude to have led to the denudation of his body 
 through natural selection, may be doubted, since none of 
 the many quadrupeds inhabiting the tropics have, as far as 
 
 *0wen, "Anatomy of Vertebrates," vol. iii, p. 619. 
 
 f Isidore Geoffrey St.-Hilaire remarks ("Hist. Nat. Generate," torn, 
 ii, 1859, pp. 215-317) on the head of man being covered with long 
 hair ; also on the upper surfaces of monkeys and of other mammals 
 being more thickly clothed than the lower surfaces. This has like- 
 wise been observed by various authors. Prof. P. Gervais (" Hist. 
 Nat. des Mammiferes," torn, i, 1854, p. 28), however, states that in 
 the gorilla the hair is thinner on the back where it is partly rubbed 
 off, than on the lower surface. 
 
 | The " Naturalist in Nicaragua," 1874, p. 209. As some confirma- 
 tion of Mr. Belt's view, I may quote the following passage from Sir 
 W. Denison ("Varieties of Vice-Regal Life," vol. i, 1870, p. 440): 
 " It is said to be a practice with the Australians, when the vermin 
 gt troublesome, to singe themselves."
 
 MANNER OF DEVELOPMENT. 65 
 
 I know, acquired any specialized means of relief. The 
 view which seems to me the most probable is that man, or 
 rather primarily woman, became divested of hair for orna- 
 mental purposes, as we shall see under Sexual Selection, 
 and, according to this belief, it is not surprising that man 
 should differ so greatly in hairiness from all other Primates, 
 for characters, gained through sexual selection, often differ 
 to an extraordinary degree in closely related forms. 
 
 According to a popular impression, the absence of a tail 
 is eminently distinctive of man ; but as those apes which 
 come nearest to him are destitute of this organ its disap- 
 pearance does not relate exclusively to man. The tail 
 often differs remarkably in length within the same genus : 
 thus in some species of Macacus it is longer than the whole 
 body, and is formed of twenty-four vertebrae; in others 
 it consists of a scarcely visible stump, containing only three 
 or four vertebrae. In some kinds of baboons there are 
 twenty-five, while in the mandrill there are ten very small 
 stunted caudal vertebrae, or, according to 'Cuvier,* some-- 
 times only five. The tail, whether it be long or short, 
 almost always tapers toward the end ; and this, I presume, 
 results from the atrophy of the terminal muscles, together 
 with their arteries and nerves, through disuse, leading to 
 the atrophy of the terminal bones. But no explanation 
 can at present be given of the great diversity which often 
 occurs in its length. Here, however, we are more specially 
 concerned with the complete external disappearance of the 
 tail. Prof. Broca has recently shownf that the tail in all 
 quadrupeds consists of two portions, generally separated 
 abruptly from each other; the basal portion consists of 
 vertebrae, more or less perfectly channeled and furnished 
 with apophyses like ordinary vertebrae; whereas those of 
 the terminal portion are not channeled, are almost smooth, 
 and scarcely resemble true vertebrae. A tail, though not 
 externally visible, is really present in man and the anthro- 
 pomorphous apes, and is constructed on exactly the same 
 pattern in both. In the terminal portion of the vertebrae, 
 
 *Mr. St. George Mivart, " Proc. Zoolog. Soc.," 1865, pp. 562, 583. 
 Dr. J. B. Gray, "Cat. Brit. Mus.: Skeletons." Owen, "Anatomy 
 of Vertebrates," vol. ii, p. 517. Isidore Geoffroy "Hist. Nat. G6n." 
 toru. ii, p. 244. 
 
 f " Revue d'Anthropologie," 1872 ; " La Constitution des Vertebras 
 caudales."
 
 66 TEE DESCENT OF MAN. 
 
 constituting the os coccyx, are quite rudimentary, being 
 much reduced in size and. number. In the basal portion, 
 the vertebrae are likewise few, are united firmly together, 
 and are arrested in development ; but they have been ren- 
 dered much broader and flatter than the corresponding 
 vertebras in the tails of other animals ; they constitute 
 what Broca calls the accessory sacral vertebras. These are 
 of functional importance by supporting certain internal 
 parts and in other ways ; and their modification is directly 
 connected with the erect or semi-erect attitude of man and 
 the anthropomorphous apes. This conclusion is the more 
 trustworthy, as Broca formerly held a different view, which 
 he has now abandoned. The modification, therefore, of 
 the basal caudal vertebras in man and the higher apes may 
 have been affected, directly or indirectly, through natural 
 selection. 
 
 But what are we to say about the rudimentary and 
 variable vertebras of the terminal portion of the tail, form- 
 ing the os coccyx ? A notion which has often been, and will 
 no doubt again be, ridiculed, namely, that friction has had 
 something to do with the disappearance of the external 
 portion of the tail, is not so ridiculous as it at first appears. 
 Dr. Anderson* states that the extremely short tail of Maca- 
 cus brunneus is formed of eleven vertebras, including the 
 imbedded basal ones. The extremity is tendinous and 
 contains no vertebras; this is succeeded by five rudimentary 
 ones, so minute that together they are only one line and a 
 half in length, and these are permanently bent to one side 
 in the shape of a hook. The free part of the tail, only a 
 little above an inch in length, includes only four more 
 small vertebras. This short tail is carried erect; but about 
 a quarter of its total length is doubled on to itself to the 
 left; and this terminal part, which includes the hook-like 
 portion, serves " to fill up the interspace between the upper 
 divergent portion of the calosities;" so that the animal sits 
 on it and thus renders it rough and callous. Dr. Anderson 
 thus sums up his observations : " These facts seem to me 
 to have only one explanation; this tail, from its short size, 
 is in the monkey's way when it sits down, and frequently 
 becomes placed under the animal while it is in this atti- 
 tude; and from the circumstance that it does not extend 
 
 * M Proc. Zoolog._Soc." 1872, p. 210.
 
 MANNER OF DEVELOPMENT. 67 
 
 beyond the extremity of the ischial tuberosities, it seems as 
 if the tail originally had been bent round by the will of the 
 animal, into the interspace between the callosities, to es- 
 cape being pressed between them and the ground, and that 
 in time the curvature became permanent, fitting in of itself 
 when the organ happens to be sat upon." Under these 
 circumstances it is not surprising that the surface of the 
 tail should have been roughened and rendered callous, and 
 Dr. Murie,* who carefully observed this species in the 
 Zoological Gardens, as well as three other closely allied 
 forms with slightly longer tails, says that when the animal 
 eits down the tail "is necessarily thrust to one side of the 
 buttocks; and whether long or short its root is consequently 
 liable to be rubbed or chafed." As we now have evidence 
 that mutilations occasionally produce an inherited effect, f 
 it is not very improbable that in short- tailed monkeys the 
 projecting part of the tail, being functionally useless, 
 should after many generations have become rudimentary 
 and distorted, from being continually rubbed and chafed. 
 We see the projecting part in this condition in the Maca- 
 cus brunneus, and absolutely aborted in the M. ecaudatus 
 and in several of the higher apes. Finally, then, as far as 
 we can judge, the tail has disappeared in man and the 
 anthropomorphous apes, owing to the terminal portion 
 having been injured by friction during a long lapse of time; 
 the basal and embedded portion having been reduced and 
 modified so as to become suitable to the erect or semi-erect 
 position. 
 
 I have now endeavored to show that some of the most 
 iistinctive characters of man have in all probability been 
 acquired, either directly, or more commonly indirectly, 
 through natural selection. We should bear in mind that 
 modifications in structure or constitution which do not 
 serve to adapt an organism to its habits of life, to the food 
 
 *"Proc. Zoolog. Soc.," 1872, p. 786. 
 
 f I allude to Dr. Brown-Sequard's obseivations on the transmitted 
 effect of an operation causing epilepsy in guinea-pigs, and likewise 
 more recently on the analogous effects of cutting the sympathetic 
 nerve in the neck. I shall hereafter have occasion to refer to Mr. 
 Salvin's interesting case of the apparently inherited effects of mot- 
 mots biting off the barbs of their own tail-feathers. See also on the 
 general subject "Variation of Auimals and Plants under Domesti- 
 cation," vol. U, pp. 28-24
 
 68 THE DESCENT OF MAN. 
 
 which it consumes, or passively to the surrounding con- 
 ditions, cannot have been, thus acquired. We must not, 
 however, be too confident in deciding what modifications 
 are of service to each being; we should remember how little 
 we know about the use of many parts, or what changes in 
 the blood or tissues may serve to fit an organism for a new 
 climate or new kinds of food. Nor must we forget the 
 principle of correlation, by which, as Isidore Geofl'roy has 
 shown in the case of man, many strange deviations ot 
 structure are tied together. Independently of correlation; 
 a change in one part often leads, through the increased 01 
 decreased use of other parts, to other changes of a quite 
 unexpected nature. It is also well to reflect on such facts, 
 as the wonderful growth of galls on plants caused by the 
 poison of an insect, and on the remarkable changes of 
 color in the plumage of parrots when fed on certain fishes, 
 or inoculated with the poison of toads; * for we can thus 
 see that the fluids of the system, if altered for some 
 special purpose, might induce other changes. We should 
 especially bear in mind that modifications acquired and 
 continually used daring past ages for some useful purpose, 
 would probably become firmly fixed, and might be long 
 inherited. 
 
 Thus a large yet undefined extension may safely be given 
 to the direct and indirect results of natural selection; but 
 I now admit, after reading the essay by Nageli on plants, 
 and the remarks by various authors with respect to ani- 
 mals, more especially those recently made by Prof. Broca, 
 that in the earlier editions of my "Origin of Species" I 
 perhaps attributed too much to the action of natural selec- 
 tion or the survival of the fittest. I have altered the fifth 
 edition of the "Origin "so as to confine my remarks to 
 adaptive changes of structure; but I am convinced, from 
 the light gained during even the last few years, that very 
 many structures which now appear to us useless, will here- 
 after be proved to be useful, and will therefore come within 
 the range of natural selection. Nevertheless, I did not 
 formerly consider sufficiently the existence of structures, 
 which, as far as we can at present judge, are neither bene- 
 ficial nor injurious; and this I believe to be one of the 
 greatest oversights as yet detected in my work. I may be 
 
 * " The Variation of Animals and Plants under Domestication," 
 vol. ii, pp. 280, 282.
 
 MANNER OF DEVELOPMENT. 69 
 
 permitted to say, as some excuse, that I had two distinct 
 objects in view; firstly, to show that species had not been 
 separately created, and secondly, that natural selection had 
 been the chief agent of change, though largely aided by 
 the inherited effects of habit, and slightly by the direct 
 action of the surrounding conditions. I was not, however, 
 able to annul the influence of my former belief, then 
 almost universal, that each species had been purposely 
 created; and this led to my tacit assumption that every de- 
 tail of structure, excepting rudiments, was of some special, 
 though unrecognized, service. Any one with this assump- 
 tion in his mind would naturally extend too far the action 
 of natural selection, either during past or present times. 
 Some of those who admit the principle of evolution, but 
 reject natural selection, seem to forget, when criticising 
 my book, that I had the above two objects in view; hence, 
 if I have erred in giving to natural selection great power, 
 which I am very far from admitting, or in having exagger- 
 ated its power, which is in itself probable, I have at least, 
 as I hope, done good service in aiding to overthrow the 
 dogma of separate creations. 
 
 It is, as I can now see, probable that all organic 
 beings, including man, possess peculiarities of structure, 
 which neither are now, nor were formerly of any service to 
 them, and which, therefore, are of no physiological im- 
 portance. We know not what produces the numberless 
 slight differences between the individuals of each species, 
 for reversion only carries the problem a few steps back- 
 ward, but each peculiarity must have had its efficient 
 cause. If these causes, whatever they may be, were to act 
 more uniformly and energetically during a lengthened 
 period (and against this no reason can be assigned), the re- 
 sult would probably be not a mere slight individual differ- 
 ence, but a well-marked and constant modification, though 
 one of no physiological importance. Changed structures, 
 which are in no way beneficial, cannot be kept uniform 
 through natural selection, though the injurious will be 
 thus eliminated. Uniformity of character would, however, 
 naturally follow from the assumed uniformity of the excit- 
 ing causes, and likewise from the free intercrossing of 
 many individuals. During successive periods, the same 
 organism might in this manner acquire successive modifi- 
 cations, which would be transmitted in a nearly uniform
 
 70 THE DESCENT OF MAN. 
 
 state as long as the exciting causes remained the same and 
 there was free intercrossing. With respect to the exciting 
 causes we can only say, as when speaking of so-called spon- 
 taneous variations, that they relate much more closely to 
 the constitution of the varying organism, than to the 
 nature of the conditions to which it has been subjected. 
 
 Conclusion. In this chapter we have seen that as man 
 at the present day is liable, like every other animal, to mul- 
 tiform individual differences or slight variations, so no 
 doubt were the early progenitors of man; the variations 
 being formerly induced by the same general causes, and 
 governed by the same general and complex laws as at 
 present. As all animals tend to multiply beyond their 
 means of subsistence, so it must have been with the pro- 
 genitors of man; and this would inevitably lead to a strug- 
 gle for existence and to natural selection. The latter pro- 
 cess would be greatly aided by the inherited effects of the 
 increased use of parts, and these two processes would in- 
 cessantly react on each other. It appears, also, as we shall 
 hereafter see, that various unimportant characters have 
 been acquired by man through sexual selection. An unex- 
 plained residuum of change must be left to the assumed 
 uniform action of those unknown agencies, which occasion- 
 ally induce strongly marked and abrupt deviations of struc- 
 ture in our domestic productions. 
 
 Judging from the habits of savages and of the greater 
 number of the Quadrumana, primeval men, and even 
 their ape-like progenitors, probably lived in society. 
 With strictly social animals, natural selection sometimes 
 'acts on the individual, through the preservation of vari- 
 ations which are beneficial to the community. A com- 
 munity which includes a large number of well-endowed 
 individuals increases in number, and is victorious over 
 other less favored ones ; even although each separate 
 member gains no advantage over the others of the same 
 community. Associated insects have thus acquired many 
 remarkable structures, which are of little or no service 
 to the individual, such as the pollen-collecting appa- 
 ratus, or the sting of the worker-bee, or the great jaws of 
 soldier-ants. With the higher social animals, I am not 
 aware that any structure has been modified solely for the 
 good of the community, though some are of secondary
 
 MANNER OF DEVELOPMENT. 71 
 
 service to it. For instance, the horns of ruminants and 
 the great canine teeth of baboons appear to have been ac- 
 quired by the males as weapons for sexual strife, but they 
 are used in defense of the herd or troop. In regard to cer- 
 tain mental powers the case, as we shall see in the fifth 
 chapter, is wholly different; for these faculties have been 
 chiefly, or even exclusively, gained for the benefit of the 
 community, and the individuals thereof have at the same 
 time gained an advantage indirectly. 
 
 It has often been objected to such views as the forego- 
 ing, that man is one of the most helpless and defenseless 
 creatures in the world; and that during his early and less 
 well developed condition he would have been still more 
 helpless. The Duke of Argyll, for instance, insists* that 
 "the human frame has diverged from the structure of 
 brutes in the direction of greater physical helplessness and 
 weakness. That is to say, it is a divergence which of all 
 others it is most impossible to ascrible to mere natural 
 selection." He adduces the naked and unprotected state 
 of the body, the absence of great teeth or claws for de- 
 fense, the small strength and speed of man, and his slight 
 power of discovering food or of avoiding danger by smell. 
 To these deficiencies there might be added one still more 
 serious, namely, that he cannot climb quickly and so 
 escape from enemies. The loss of hair would not have 
 been a great injury to the inhabitants of a warm country. 
 For we know that the unclothed Fuegians can exist under 
 a wretched climate. When we compare the defenseless 
 state of man with that of apes we must remember that the 
 great canine teeth with which the latter are provided are 
 possessed in their full development by the males alone, and 
 are chiefly used by them for fighting with their rivals; 
 yet the females, which are not thus provided, manage to 
 survive. 
 
 In regard to bodily size or strength, we do not know 
 whether man is descended from some small species, like 
 the chimpanzee, or from one as powerful as the gorilla; 
 and, therefore, we cannot say whether man has become 
 larger and stronger, or smaller and weaker than his ances- 
 tors. We should, however, bear in mind that an 
 
 "Primeval Man," 1869, p. 66.
 
 72 THE DESCENT OF MAN. 
 
 possessing great size, strength, and ferocity, and which, 
 like the gorilla, could defend itself from all enemies, would 
 not perhaps have become social: and this would most effect- 
 ually have checked the acquirement of the higher mental 
 qualities, such as sympathy and the love of his fellows. 
 Hence it might have been an immense advantage to man to 
 have sprung from some comparatively weak creature. 
 
 The small strength and speed of man, his want of nat- 
 ural weapons, etc., are more than counterbalanced, firstly, 
 by his intellectual powers, through which he has formed 
 for himself weapons, tools, etc., though still remaining in 
 a barbarous state, and secondly, by his social qualities which 
 lead him to give and receive aid from his fellow-men. No 
 country in the world abounds in a greater degree with dan- 
 gerous beasts than Southern Africa; no country presents 
 more fearful physical hardships than the Arctic regions; 
 yet one of the puniest of races, that of the Bushmen, main- 
 tains itself in Southern Africa, as do the dwarfed Esqui- 
 maux in the Arctic regions. The ancestors of man were, 
 no doubt, inferior in intellect, and probably in social dis- 
 position to the lowest existing savages; but it is quite con- 
 ceivable that they might have existed, or even nourished, 
 if they had advanced in intellect, while gradually losing 
 their brute-like powers, such as that of climbing trees, etc. 
 But these ancestors would not have been exposed to any 
 special danger, even if far more helpless and defenseless 
 than any existing savages, had they inhabited some warm 
 continent or large island, such as Australia, New Guinea, 
 or Borneo, which is now the home of the orang. And 
 natural selection arising from the competition of tribe with 
 tribe in some such large area as one of these, together with 
 the inherited effects of habit, would, under favorable con- 
 ditions, have sufficed to raise man to his present high 
 position in the organic scale.
 
 MENTAL POWERS. 73 
 
 CHAPTER III. 
 
 COMPARISON" OF THE MENTAL POWERS OF MAN AND THE 
 LOWER ANIMALS. 
 
 The difference in mental power between the highest ape and the 
 lowest savage, immense Certain instincts in common The 
 emotions Curiosity Imitation Attention Memory Imagi- 
 nation Reason Progressive improvement Tools and weapons 
 used by animals Abstraction, self-consciousness Language 
 Sense of beauty Belief in God, spiritual agencies, superstitions. 
 
 WE have seen in the last two chapters that man bears 
 in his bodily structure clear traces of his descent from 
 some lower form; but it maybe urged that, as man differs 
 so greatly in his mental power from all other animals, 
 there must be some error in this conclusion. No doubt the 
 difference in this respect is enormous, even if we compare 
 the mind of one of the lowest savages, who has no words 
 to express any number higher than four, and who uses 
 hardly any abstract terms for common objects or for the 
 affections,* with that of the most highly organized ape. 
 The difference would, no doubt, still remain immense, even 
 if one of the higher apes had been improved or civilized as 
 much as a dog has been in comparison with its parent-form, 
 the wolf or jackal. The Fuegians rank among the lowest 
 barbarians ; but I was continually struck with surprise how 
 closely the three natives on board H.M.S. "Beagle," who 
 had lived some years in England, and could talk a little 
 English, resembled us in disposition and in most of our 
 mental faculties. If no organic being excepting man had 
 possessed any mental power, or if his powers had been of a 
 wholly different nature from those of the lower animals, 
 then we should never have been able to convince ourselves 
 that our high faculties had been gradually developed. But 
 
 * See the evidence on those points, as given by Lubbock, " Prehis- 
 toric Times," p. 354, etc.
 
 ?4 THE DESCENT OF MAN. 
 
 it can be shown that there is no fundamental difference of 
 this kind. We must also admit that there is a much wider 
 interval in mental power between one of the lowest fishes, 
 as a lamprey or lancelet, and one of the higher apes, than 
 between an ape and man; yet this interval is filled up by 
 numberless gradations. 
 
 Nor is the difference slight in moral disposition between 
 a barbarian, such as the man described by the old navi- 
 gator Byron, who dashed his child on the rocks for drop- 
 ping a basket of sea-urchins, and a Howard or Clarkson; 
 and in intellect, between a savage who uses hardly any ab- 
 stract terms, and a Newton or Shakespeare. Differences 
 of this kind between the highest men of the highest races 
 and the lowest savages are connected by the finest grada- 
 tions. Therefore it is possible that they might pass and be 
 developed into each other. 
 
 My object in this chapter is to show that there is no fun- 
 damental difference between man and the higher mammals 
 in their mental faculties. Each division of the subject 
 might have been extended into a separate essay, but must 
 here be treated briefly. As no classification of the mental 
 powers has been universally accepted, I shall arrange my 
 remarks in the order most convenient for my purpose; and 
 will select those facts which have struck me most, with the 
 hope that they may produce some effect on the reader. 
 
 With respect to animals very low in the scale, I shall give 
 some additional facts under Sexual Selection, showing that 
 their mental powers are much higher than might have been 
 expected. The variability of the faculties in the individ- 
 uals of the same species is an important point for us, and 
 some few illustrations will here be given. But it would be 
 superfluous to enter into many details on this head, for I 
 have found on frequent inquiry that it is the unanimous 
 opinion of all those who have long attended to animals of 
 many kinds, including birds, that the individuals differ 
 greatly in every mental characteristic. In what manner 
 the mental powers were first developed in the lowest organ- 
 isms, is as hopeless an inquiry as how life itself first origi- 
 nated. These are problems for the distant future if they are 
 ever to be solved by man. 
 
 As man possesses the same senses as the lower animals, 
 his fundamental intuitions must be the same. Man has 
 also some few instincts in common, as that of self-preserva-
 
 MENTAL POWERS. 75 
 
 tiou, sexual love, the love of the mother for her new-born 
 offspring, the desire possessed by the latter to suck, and so 
 forth. But man, perhaps, has somewhat fewer instincts 
 than those possessed by the animals which come next to 
 him in the series. The orang in the. Eastern islands and 
 the chimpanzee in Africa build platforms on which they 
 sleep; and as both species follow the same habit, it might 
 be argued that this was due to instinct, but we cannot feel 
 sure that it is not the result of both animals having similar 
 wants and possessing similar powers of reasoning. These 
 apes, as we may assume, avoid the many poisonous fruits of 
 the tropics, and man has no such knowledge; but as our 
 domestic animals, when taken to foreign lands, and when 
 first turned out in the spring, often eat poisonous herbs, 
 which they afterward avoid, we cannot feel sure that the 
 apes do not learn from their own experience or from that of 
 their parents Avhat fruits to select. It is, however, certain, 
 as we shall presently see, that apes have an instinctive dread 
 of serpents, and probably of other dangerous animals. 
 
 The fewness and the comparative simplicity of the in- 
 stincts in the higher animals are remarkable in contrast 
 with those of the lower animals. Cuvier maintained 
 that instinct and intelligence stand in an inverse ratio to 
 each other ; and some have thought that the intellectual 
 faculties of the higher animals have been gradually de- 
 veloped from their instincts. But Pouchet, in an interest- 
 ing essay,* has shown that no such inverse ratio really 
 exists. Those insects which possess the most wonderful 
 instincts are certainly the most intelligent. In the ver- 
 tebrate series, the least intelligent members, namely fishes 
 land amphibians, do not possess complex instincts ; and 
 'among mammals the animal most remarkable for its instincts, 
 namely the beaver, is highly intelligent, as will be admitted 
 by every one who has read Mr. Morgan's excellent work.f 
 
 Although the first dawnings of intelligence, according to 
 Mr. Herbert Spencer, J have been developed through the 
 multiplication and co-ordination of reflex actions, and 
 although many of the simpler instincts graduate into reflex 
 
 * " L'Instinct cliez les Insectes," "Revue des Deux Mondes," Feb. 
 1870, p. 690. 
 
 f " The American Beaver and His Works," 1868. 
 
 J" The Principles of Psychology," 3d edit., 1870, pp. 418-443.
 
 76 THE DESCENT OF MAN. 
 
 actions, and can hardly be distinguished from them, as in 
 the case of young animals sucking, yet the more complex 
 instincts seem to have originated independently of intelli- 
 gence. I am, however, very far from wishing to deny that 
 instinctive actions may lose 'their fixed and untaught char- 
 acter and he replaced by others performed by the aid of the 
 free will. On the other hand, some intelligent actions, 
 after being performed during several generations, become 
 converted into instincts and are inherited, as when birds 
 on oceanic islands learn to avoid man. These actions may 
 then be said to be degraded in character, for they are no 
 longer performed through reason or from experience. But 
 the greater number of the more complex instincts appear 
 to have been gained in a wholly different manner, through 
 the natural selection of variations of simpler instinctive 
 actions. Such variations appear to arise from the same 
 unknown causes acting on the cerebral organization, which 
 induce slight variations or individul differences in other 
 parts of the body ; and these variations, owing to our 
 ignorance, are often said to arise spontaneously. We can, 
 I think, come to no other conclusion with respect to the 
 origin of the more complex instincts, when we reflect on 
 the marvelous instincts of sterile worker-ants and bees, 
 which leave no offspring to inherit the effects of experience 
 and of modified habits. 
 
 Although, as we learn from the above-mentioned insects 
 and the beaver, a high degree of intelligence is certainly 
 compatible with complex instincts, and although actions, 
 at first learned voluntarily, can soon through habit be 
 performed with the quickness and certainty of a reflex 
 action, yet it is not improbable that there is a certain 
 amount of interference between the development of free 
 intelligence and of instinct, which latter implies some in- 
 herited modification of the brain. Little is known about 
 the functions of the brain, but we can perceive "that as the 
 intellectual powers become highly developed the various 
 parts of the brain must be connected by very intricate 
 channels of the freest intercommunication; and as a conse- 
 quence each separate part would perhaps tend to be less 
 well fitted to answer to particular sensations or associations 
 in a definite and inherited that is instinctive manner. 
 There seems even to exist some relation between a low de- 
 gree of intelligence and a strong tendency to the formation
 
 MENTAL POWERS. 77 
 
 of fixed, though not inherited habits; for as a sagacious 
 physician remarked to me, persons who are slightly imbecile 
 tend to act in everything by routine or habit; and they are 
 rendered much happier if this is encouraged. 
 
 I have thought this digression worth giving, because we 
 may easily underrate the mental powers of the higher ani- 
 mals, and especially of man, when we compare their actions 
 founded on the memory of past events, on foresight, reason 
 and imagination, with exactly similar actions instinctively 
 performed by the lower animals; in this latter case the 
 capacity of performing such actions has been gained, step 
 by step, through the variability of the mental organs and 
 natural selection, without any conscious intelligence on the 
 part of the animal during each successive generation. No 
 doubt, as Mr. Wallace has argued,* much of the intelligent 
 work done by man is due to imitation and not to reason; 
 but there is this great difference between his actions and 
 many of those performed by the lower animals, namely, 
 that man cannot, on his first trial, make, for instance, a 
 stone hatchet or a canoe, through his power of imitation. 
 He has to learn his work by practice; a beaver, on the other 
 hand, can make its dam or canal, and a bird its nest, as 
 well, or nearly as well, and a spider its wonderful web, 
 quite as well,f the first time it tries as when old and 
 experienced. 
 
 To return to our immediate subject; the lower animals, 
 like man, manifestly feel pleasure and pain, happiness and 
 misery. Happiness is never better exhibited than by 
 young animals, such as puppies, kittens, lambs, etc., when 
 playing together, like our own children. Even insects 
 play together, as has been described by that excellent 
 observer, P, Huber,J who saw ants chasing and pretending 
 to bite each other, like so many puppies. 
 
 The fact that the lower animals are excited by the same 
 emotions as ourselves is so well established that it will 
 not be necessary to weary the reader by many details. 
 Terror acts in the same manner on them as on us, causing 
 the muscles to tremble, the heart to palpitate, the 
 
 * "Contributions to the Theory of Natural Selection," 1870, p. 212. 
 
 f For the evidence on this head, see Mr J. Traherne Moggridge's 
 most interesting work, "Harvesting Ants and Trap-door Spiders/' 
 1873, pp. 126, 128. 
 
 \ " Recherches sur les Mosurs des Fourmis," 1810, p. 178.
 
 78 THE DESCENT OF MAN. 
 
 sphincters to be relaxed, and the hair to stand on end. 
 Suspicion, the offspring of .fear, is eminently characteristic 
 of most wild animals. It is, I think, impossible to read the 
 account given by Sir E. Tennent, of the behavior of the 
 female elephants, used as decoys, without admitting that 
 they intentionally practice deceit, and well know what they 
 are about. Courage and timidity are extremely variable 
 qualities in the individuals of the same species, as is plainly 
 seen in our dogs. Some dogs and horses are ill-tempered 
 and easily turn sulky; others are good-tempered; and these 
 qualities are certainly inherited. Every one knows how 
 liable animals are to furious rage and how plainly they 
 show it. Many, and probably true, anecdotes have been 
 published on the long-delayed and artful revenge of various 
 animals. The accurate Rengger and Brehm* state that 
 the American and African monkeys which they kept tame 
 certainly revenged themselves. Sir Andrew Smith, a zoolo- 
 gist whose scrupulous accuracy was known to many persons, 
 told me the following story of which he was himself an eye- 
 witness: At the Cape of Good Hope an officer had often 
 plagued a certain baboon, and the animal, seeing him ap- 
 proaching one Sunday for parade, poured water into a hole 
 and hastily made some thick mud, which he skillfully 
 dashed over the officer as he passed by, to the amusement 
 of many bystanders. For long afterward the baboon re- 
 joiced and triumphed whenever he saw his victim. 
 
 The love of a dog for his master is notorious ; as an old 
 writer quaintly says; f "A dog is the only thing on this 
 earth that luvs you more than he luvs himself. " 
 
 In the agony of death a dog has been known to caress his 
 master, and every one has heard of the dog suffering under 
 vivisection, who licked the hand of the operator; this man, 
 unless the operation was fully justified by an increase of our 
 knowledge, or unless he had a heart of stone, must have 
 felt remorse to the last hour of his life. 
 
 As Whewell % has well asked ; " Who that reads the 
 
 *A11 the following statements, given on the authority of these two 
 naturalists, are taken from Rengger's " Naturgesch. der Saugethiere 
 von Paraguay," 1830, B. 41-57, and from Brehm's " Thierleben," B. 
 i, s. 10-87. 
 
 f Quoted by Dr. Lauder Lindsay, in his " Physiology of Mind in 
 the Lower Animals;" "Journal of Mental Science," April, 1871, p. 
 38. 
 
 \ " Bridgewater Treatise," p. 263.
 
 MENTAL POWERS. 79 
 
 touching instances of maternal affection, related so often 
 of the women of all nations and of the females of all ani- 
 mals, can doubt that the principle of action is the same in 
 the two cases?" We see maternal affection exhibited in 
 the most trifling details; thus, Rengger observed an Ameri- 
 can monkey (a Cebus) carefully driving away the flies 
 which plagued her infant; and Duvaucel saw a Hylobates 
 washing the faces of her young ones in a stream. So in- 
 tense is the grief of female monkeys for the loss of their 
 young that it invariably caused the" death of certain kinds 
 kept under confinement by Brehm in N. Africa. Orphan 
 monkeys were always adopted and carefully guarded by the 
 other monkeys, both males and females. One female 
 baboon had so capacious a heart that she not only adopted 
 young monkeys of other species, but stole young dogs and 
 cats, which she continually carried about. Her kindness, 
 however, did not go so far as to share her food with her 
 adopted offspring, at which Brehm was surprised, as his 
 monkeys always divided everything quite fairly with their 
 own young ones. An adopted kitten scratched this affec- 
 tionate baboon, who certainly had a fine intellect, for she was 
 much astonished at being scratched, and immediately exam- 
 ined the kitten's feet, and without more ado bit off the claws.* 
 In the Zoological Gardens I heard from the keeper that an 
 old baboon (C. cliacma) had adopted a Rhesus monkey; but 
 when a young drill and mandrill were placed in the cage 
 she seemed to perceive that these monkeys, though distinct 
 species, were her nearer relatives, for she at once rejected 
 the Rhesus and adopted both of them. The young Rhesus, 
 as I saw, was greatly discontented at being thus rejected, 
 and it would, like a naughty child, annoy and attack the 
 young drill and mandrill whenever it could do so with 
 safety; this conduct exciting great indignation in the old 
 baboon. Monkeys will also, according to Brehm, defend 
 their master when attacked by any one, as well as dogs to 
 whom they are attached, from the attacks of other dogs. 
 But we here trench on the subjects of sympathy and fidel- 
 ity, to which I shall recur. Some of Brehm's monkeys 
 
 *A critic, without any grounds (" Quarterly Review," July, 1871, 
 p. 72), disputes the possibility of this act as described by Brehm, for 
 the sake of discrediting niy work. Therefore I tried, and found that 
 I could readily seize with my own teeth the sharp little claws of a 
 kitten nearly five weeks old.
 
 80 THE DESCENT OF MAN. 
 
 took muoh delight in teasing a certain old dog whom they 
 disliked, as well as other animals, in various ingenious ways. 
 
 Most of the more complex emotions are common to the 
 higher animals and ourselves. Every one has seen how 
 jealous a dog is of his master's affection if lavished on any 
 other creature; and I have observed the same fact with 
 monkeys. This shows that animals not only love, but have 
 a desire to be loved. Animals manifestly feel emulation. 
 They love approbation or praise; and a dog carrying a bas- 
 ket for his master exhibits in a high degree self-complac- 
 ency or pride. There can, I think, be no doubt that a dog 
 feels shame, as distinct from fear, and something very like 
 modesty when begging too often for food. A great dog 
 Bcorns the snarling of a little dog, and this may be called 
 magnanimity. Several observers have stated that monkeys 
 certainly dislike being laughed at; and they sometimes in- 
 vent imaginary offenses. In the Zoological Gardens I saw 
 a baboon who always got into a furious rage when his keeper 
 took out a letter or book and read it aloud to him; and his 
 rage was so violent that, as I witnessed on one occasion, he 
 bit his own leg till the blood flowed. Dogs show what may 
 be fairly called a sense of humor as distinct from mere play; 
 if a bit of stick or other such object be thrown to one, he 
 will often carry it away for a short distance ; and then 
 squatting down with it on the ground close before him, will 
 wait until his master comes quite close to take it away. 
 The dog will then seize it and ru&h away in triumph, re- 
 peating the same maneuver, a\id evidently enjoying the 
 practical joke. 
 
 We will now turn to the more intellectual emotions and 
 faculties, which are very important, as forming the basis 
 for the development of the higher mental powers. Animals 
 manifestly enjoy excitement, and suffer from ennui, as may 
 be seen with dogs, and, according to Kengger, with mon- 
 keys. All animals feel Wonder and many exhibit Curiosity. 
 Tbe> sometimes suffer from this latter quality, as when 
 the hunter plays antics and thus attracts them; I have wit- 
 nessed this with deer, and so it is with the wary chamois, 
 and with some kinds of wild-ducks. Brehni gives a curious 
 account of the instinctive dread, which his monkeys exhib- 
 ited, for snakes; but their curiosity was so great that they 
 could not desist from occasionally satiating their horror 
 in a most human fashion by lifting up the lid of the box
 
 MENTAL POWERS. 81 
 
 in which the snakes were kept. I was so much surprised 
 at his account that I took a stuffed and coiled-up snake 
 into the monkey-house at the Zoological Gardens, and the 
 excitement thus caused was one of the most curious spec- 
 tacles which I ever beheld. Three species of Cercopithecus 
 were the most alarmed ; they dashed about their cages and 
 uttered sharp signal cries of danger, which were understood 
 by the other monkeys. A few young monkeys and one old 
 Anubis baboon alone took no notice of the snake. I then 
 placed the stuffed specimen on the ground in one of the 
 larger compartments. After a time all the monkeys col- 
 lected round it in a large circle, and, staring intently, pre- 
 sented a most ludicrous appearance. They became ex- 
 tremely nervous; so that when a wooden ball, with which 
 they were familiar as a plaything, was accidentally moved 
 in the straw, under which it was partly hidden, they all in- 
 stantly started away. These monkeys behaved very dif- 
 ferently when a dead fish, a mouse,* a living turtle, and 
 other new objects were placed in their cages; for though at 
 first frightened, they soon approached, handled and ex- 
 amined them. I then placed a live snake in a paper bag, 
 with the mouth loosely closed, in one of the larger com- 
 partments. One of the monkeys immediately approached, 
 cautiously opened the bag a little, peeped in, and instantly 
 dashed away. Then I witnessed what Brehm has described, 
 for monkey after monkey, with head raised high and turned 
 on one side, could not resist taking a momentary peep into 
 the upright bag, at the dreadful object lying quietly at the 
 bottom. It would almost appear as if monkeys had some 
 notion of zoological affinities, for those kept by Brehm ex- 
 hibited a strange, though mistaken, instinctive dread of 
 innocent lizards and frogs. An orang, also, has been 
 known to be much alarmed at the first sight of a turtle, f 
 The principle of Imitation is strong in man, and espe 
 cially, as I have myself observed, with savages. In certain 
 morbid states of the brain this tendency is exaggerated to an 
 extraordinary degree; some hemiplegic patients and others, 
 at the commencement of inflammatory softening of the brain, 
 unconsciously imitate every word which is uttered, whether 
 
 * I have given a short account of their behavior on this occasion in 
 my "Expression of the Emotions," p. 43. 
 
 fW. 0. L, Martin, " Nat. Hist of Mammalia." 1841, p. 405.
 
 88 THE DESCENT OF MAN". 
 
 in their own or in a foreign language, and every gesture 01 
 action which is performed near them. * Desor f has re- 
 marked that no animal voluntarily imitates an action per- 
 formed by man, until in the ascending scale we come to 
 monkeys, which are well known to be ridiculous mockers 
 Animals, however, sometimes imitate each other's actions ; 
 thus two species of wolves, which had been reared by dogs, 
 learned to bark, as does sometimes the jackal, J but whether 
 this can be called voluntary imitation is another question, 
 Birds imitate the songs of their parents, and sometimes of 
 other birds; and parrots are notorious imitators of any sound 
 which they often hear. D ureau do la Malle gives an account 
 of a dog reared by a cat, who learned to imitate the well- 
 known action of a cat licking her paws, and thus washing 
 her ears and face; this was also witnessed by the celebrated 
 naturalist Audouin. I have received several confirmatory 
 accounts; in one of these, a dog had not been suckled by a 
 cat, but had been brought up with one, together with 
 kittens, and had thus acquired the above habit, which he 
 ever afterward practiced during his life of thirteen years. 
 Bureau de la Malleus dog likewise learned from the kittens 
 to play with a ball by rolling it about with his fore paws 
 and springing on it. A correspondent assures me that a 
 cat in his house used to put her paws into jugs of milk 
 having too narrow a mouth for her head. A kitten of this 
 cat soon learned the same trick, and practiced it ever 
 afterward whenever there was am opportunity. 
 
 The parents of many animals, trusting to the principle 
 of imitation in their young, and more especially to their 
 instinctive or inherited tendencies, may be said to educate 
 them. We see this when a cat brings a live mouse to her 
 kittens; and Bureau de la Malle has given a curious ac- 
 count (in the paper above quoted) of his observations on 
 hawks which taught their young dexterity, as well as judg- 
 ment of distances, by first dropping through the air dead 
 mice and sparrows, which the young generally failed to 
 
 *I>r. Bateman "On Aphasia," 1870, p. 110. 
 
 f Quoted by Vogt, " Memoire sur les Microcephales," 1867, p. 168. 
 
 * " The Variation of Animals and Plants under Domestication," vol. 
 I, p. 27. 
 
 " Annales des Sc. Nat." (1st series), torn, xxii, p. 397.
 
 MENTAL POWERS. 83 
 
 catch, and then bringing them live birds and letting them 
 loose. 
 
 Hardly any faculty is more important for the intellectual 
 progress of man than Attention. Animals clearly manifest 
 this power, as when a cat watches by a hole and prepares 
 to spring on its prey. Wild animals sometimes become so 
 absorbed when thus engaged that they may be easily ap- 
 proached. Mr. Bartlett has given me a curious proof how 
 variable this faculty is in monkeys. A man who trains 
 monkeys to act in plays used to purchase common kinds 
 from the Zoological Society at the price of five pounds f 01 
 each; but he offered to give double the price if he might 
 keep three or four of them for a few days in order to select 
 one. When asked how he could possibly learn so soon 
 whether a particular monkey would turn out a good actor, 
 he answered that it all depended on their power of atten- 
 tion. If when he was talking and explaining anything to 
 a monkey its attention was easily distracted, as by a fly on 
 the wall or other trifling object, the case was hopeless. If 
 he tried by punishment to make an inattentive monkey act 
 it turned sulky. On the other hand, a monkey which 
 carefully attended to him could always be trained. 
 
 It is almost superfluous to state that animals have excel- 
 lent memories for persons and places. A baboon at the 
 Cape of Good Hope, as I have been informed by Sir An- 
 drew Smith, recognized him with joy after an absence of 
 nine months. I had a dog who was savage and averse to 
 all strangers, and I purposely tried his memory after an 
 absense of five years and two days. I went near the stable 
 where he lived and shouted to him in my old manner; he 
 showed no joy, but instantly followed me out walking, and 
 obeyed me exactly as if I had parted with him only half an 
 hour before. A train of old associations, dormant during 
 five years, had thus been instantaneously awakened in his 
 mind. Even ants, as P. Huber* has clearly shown, recog- 
 nized their fellow-ants belonging to the same community 
 after a separation of four months. Animals can certainly 
 by some means judge of the intervals of time between 
 recurrent events. 
 
 The Imagination is one of the highest prerogatives of 
 man. By this faculty he unites former images and ideas, 
 
 *"Les Mceurs des Fourmis," 1810, p. 150.
 
 84 THE DESCENT OF MAN. 
 
 independently of the will, and thus creates brilliant and 
 novel results. A poet, as Jean Paul Eichter remarks,* 
 ' ' who must reflect wlietlier he shall make a character say 
 yes or no to the devil Avith him ; he is only a stupid 
 corpse." Dreaming gives us the best notion of this power; 
 as Jean Paul again says, " The dream is an involuntary art 
 of poetry." The value of the products of our imagination 
 depends of course on the number, accuracy, and clearness 
 of our impressions, on our judgment and taste in selecting 
 or rejecting the involuntary combinations, and to a certain 
 extent on our power of voluntarily combining them. As 
 dogs, cats, horses, and probably all the higher animals, 
 even birds f have vivid dreams, and this is shown by their 
 movements and the sounds uttered, we must admit that 
 they possess some power of imagination. There must be 
 something special which causes dogs to howl in the night, 
 and especially during moonlight, in that remarkable and 
 melancholy manner called baying. All dogs do not do so; 
 and, according to Houzeau,;J; they do not then look at the 
 moon, but at some fixed point near the horizon. Hotizeau 
 thinks that their imaginations are disturbed by the vague 
 outlines of the surrounding objects, and conjure up before 
 them fantastic images ; if this be so, their feelings may 
 almost be called superstitious. 
 
 Of all the faculties of the human mind, it will, I pre- 
 sume, be admitted that Reason stands at the summit. Only 
 a few persons now dispute that animals possess some power 
 of reasoning. Animals may constantly be seen to pause, 
 deliberate, and resolve. It is a significant fact, that the 
 more the habits of any particular animal are studied by a 
 naturalist, the more he attributes to reason and the less to 
 unlearned instincts. In future chapters we shall see that 
 some animals extremely low in the scale apparently display 
 
 * Quoted in Dr. Maudsley's " Physiology and Pathology of Mind," 
 1868, pp. 19, 220. 
 
 f Dr. Jerdon, "Birds of India," vol. i, 1862, p. 21. Houzeau says 
 that his paroquets and canary birds dreamed: " Facultes Mentales," 
 torn, ii, p. 136. 
 
 J " Facultes Mentales des Animaux," 1872, torn, ii, p. 181. 
 
 Mr. L. H. Morgan's work on "The American Beaver," 1866, 
 offers a good illustration of this remark. I cannot help thinking, 
 however, that he goes too far in underrating the power of instinct.
 
 MENTAL POWERS. 85 
 
 a certain amount of reason. Xo doubt it is often difficult 
 to distinguish between the power of reason and that of in- 
 stinct. For instance, Dr. Hayes,, in his work on "The 
 Open Polar Sea/' repeatedly remarks that his dogs, instead 
 of continuing to draw the sledges in a compact body, 
 diverged and separated when they came to thin ice, so that 
 their weight might be more evenly distributed. This was 
 often the first warning which the travelers received that the 
 ice was becoming thin and dangerous. Now, did the dogs 
 act thus from the experience of each individual, or from 
 the example of the older and wiser dogs, or from an inher- 
 ited habit, that is, from instinct? This instinct may pos- 
 sibly lia^'e arisen since the time, long ago, when dogs were 
 first employed by the natives in drawing their sledges; or 
 the Arctic wolves, the parent-stock of the Esquimau dog, 
 may have acquired an instinct impelling them not to attack 
 their prey in a close pack, when on thin ice. 
 
 AYe can only judge by the circumstances under which 
 actions are performed, whether they are due to instinct, or 
 to reason, or to the mere association of ideas; this latter 
 principle, however, is intimately connected with reason. A 
 curious case has been given by Prof. Mobius,* of a pike, 
 separated by a plate of glass from an adjoining aquarium 
 stocked with fish, and who often dashed himself with such 
 violence against the glass in trying to catch the other fishes, 
 that he was sometimes completely stunned. The pike went 
 on thus for three months, but at last learned caution, and 
 ceased to do so. The plate of glass was then removed, but 
 the pike would not attack these particular fishes, though he 
 would devour others which were afterward introduced ; so 
 strongly was the idea of a violent shock associated in his 
 feeble mind with the attempt on his former neighbors. If 
 a savage, who had never seen a large plate-glass window, 
 were to dash himself even once against it, he would for a 
 long time afterward associate a shock with a window-frame; 
 but, very differently from the pike, he would probably 
 reflect on the nature of the impediment, and be cautious 
 under analogous circumstances. Now with monkeys, as we 
 shall presently see, a painful or merely a disagreeable 
 impression, from an action once performed, is sometimes 
 sufficient to prevent the animal from repeating it. If we 
 
 * "Die Bewegungen der Tliiere," etc=, 1873, p. 11.
 
 86 THE DESCENT OF MAN. 
 
 attribute this difference between the monkey and the pike 
 solely to the association of ideas being so much stronger 
 and more persistent in the one than the other, though the 
 pike often received much the more severe injury, can we 
 maintain in the case of man that a similar difference 
 implies the possession of a fundamentally different mind? 
 
 Houzeau relates* that, while crossing a wide and arid 
 ; >lain in Texas, his two dogs suffered greatly from thirst, 
 and that between thirty and forty times they rushed down 
 the hollows to search for water. These hollows were not 
 valleys, and there were no trees in them, or any other differ- 
 ence in the vegetation, and, as they were absolutely dry, 
 there could have been no smell of damp earth. The dogs 
 oehaved as if they knew that a dip in the ground offered 
 tnem the best chance of finding water, and Houzeau has 
 oftened witnessed the same behavior in other animals. 
 
 I have seen, as I dare say have others, that when a small 
 object is thrown on the ground beyond the reach of one of 
 the elephants in the Zoological Gardens, he blows through 
 his trunk on the ground beyond the object, so that the cur- 
 rent reflected on all sides may drive the object within his 
 reach. Again, a well-known ethnologist, Mr. "Westropp, 
 informs me that he observed in Vienna a bear deliberately 
 making with his paw a current in some water, which was 
 close to the bars of his cage, so as to draw a piece of float- 
 ing bread within his reach. These actions of the elephant 
 and bear can hardly be attributed to instinct or inherited 
 habit, as they would be of little use to an animal in a state 
 of nature. Now, what is the difference between such 
 actions, when performed by an uncultivated man, and by 
 one of the higher animals? 
 
 The savage and the dog have often found water at a low 
 level, and the coincidence under such circumstances has 
 become associated in their minds. A cultivated man 
 would perhaps make some general proposition on the sub- 
 ject; but from all that we know of savages it is extremely 
 doubtful whether they would do so, and a dog certainly 
 would not. But a savage, as well as a dog, would search 
 In the same way, though frequently disappointed, and in 
 both it seems to be equally an act of reason, whether or not 
 any general proposition on the subject is consciously placed 
 
 *Facult6sMentales des Animaux," 1872, toin. ii. p. 265
 
 MENTAL POWERS. 87 
 
 before the mind.* The same would apply to the elephant 
 and the bear making currents in the air or water. The 
 savage would certainly neither know nor care by what law 
 the desired movements were effected; yet his act would be 
 guided by a rude process of reasoning, as surely as would a 
 philosopher in his longest chain of deductions. There 
 would no doubt be this difference between him and one of 
 the higher animals, that he would take notice of much 
 slighter circumstances and conditions, and would observe 
 any connection between them after much less experience, 
 and this would be of paramount importance. I kept a 
 daily record of the actions of one of my infants, and when 
 he was about eleven months old, and before he could speak 
 a single word, I was continually struck with the greater 
 quickness with which all sorts of objects and sounds were 
 associated together in his mind, compared with that of the 
 most intelligent dogs I ever knew. But the higher ani- 
 mals differ in exactly the same way in this power of associ- 
 ation from those low in the scale, such as the pike, as well 
 as in that of drawing inferences and of observation. 
 
 The promptings of reason, after very short experience, 
 are well shown by the following actions of American mon- 
 keys, which stand low in their order. Rengger, a most 
 careful observer, states that when he first gave eggs to his 
 monkeys in Paraguay they smashed them and thus lost 
 much of their contents; afterward they gently hit one end 
 against some hard body, and picked off the bits of shell 
 with their fingers. After cutting themselves only once 
 with any sharp tool, they would not touch it again, or 
 would handle it with the greatest caution. Lumps of 
 sugar were often given them wrapped up in paper ; and 
 Rengger sometimes put a live wasp in the paper, so that in 
 hastily unfolding it they got stung; after this had once hap- 
 pened they always first held the packet to their ears to de- 
 tect any movement within, f 
 
 * Prof, Huxley has analyzed with admirable clearness the mental 
 steps by which a man, as well as a dog, arrives at a conclusion in a 
 case analogous to that given in my text. See his article, "Mr. Dar- 
 win's Critics," in the "Contemporary Review," Nov, 1871, p. 462, 
 and in his " Critiques and Essays/' 1873, p. 279. 
 
 fMr. Belt, in his most interesting work, "The Naturalist in Nic- 
 aragua," 1874 (p. 119), likewise describes various actions of a tamed 
 Cebus, which, I think, clearly show that this animal possessed som<? 
 reasoning power.
 
 88 THE DESCENT OF MAN. 
 
 The following cases relate to dogs. Mr. Cok|uhoun* 
 winged two wild-ducks, which fell on the farther side of a 
 stream; his retriever tried to bring over both at once, but 
 could not succeed; she then, though never before known to 
 ruffle a feather, deliberately killed one, brought over 
 the other, and returned for the dead bird. Col. 
 Hutchinson relates that two partridges were shot at once^ 
 one being killed, the other wounded; the latter ran away 
 and was caught by the retriever, who on her return came 
 across the dead bird; " she stopped, evidently greatly puz- 
 zled, and after one or two trials, finding she could not take 
 it up without permitting the escape of the winged bird, she 
 considered a moment, then deliberately murdered it by giv- 
 ing it a severe crunch, and afterward brought away both 
 together. This was the only known instance of her ever 
 having wilfully injured any game." Here we have reason, 
 though not quite perfect, for the retriever might have 
 brought the wounded bird first and then returned for the 
 dead one, as in the case of the two wild-ducks. I give the 
 above cases as resting on the evidence of two independent 
 witnesses, and because in both instances the retrievers, after 
 deliberation, broke through a habit which is inherited by 
 them (that of not killing the game retrieved), and because 
 they show how strong their reasoning faculty must have 
 been to overcome a fixed habit. 
 
 I will conclude by quoting a remark by the illustrious 
 Humboldt.f "The muleteers in South America say, 'I 
 will not give you the mule whose step is easiest, but la mas 
 racional the one that reasons best;'" and, as he adds, 
 " this popular expression, dictated by long experience, com- 
 bats the system of animated machines better perhaps than 
 all the arguments of speculative philosophy." Neverthe- 
 less some writers even yet deny that the higher animals pos- 
 sess a trace of reason; and they endeavor to explain away, 
 by what appears to be mere verbiage,]; all such facts as those 
 above given. 
 
 *"The Moor and the Loch," p. 45. Col. Hutchinson on "Dog 
 Breaking," 1850, p. 46. 
 f "Personal Narrative," Eng. translat., vol. iii, p. 106. 
 
 II am glad to find that so acute a reasoner as Mr. Leslie Stephen 
 ("Darwinism and Divinity, Essays on Free-thinking," 1873, p. 80), 
 in speaking of the supposed impassable barrier between the minds of 
 man and the lower animals, says: " The distinctions, indeed, which
 
 MENTAL POWERS. 89 
 
 It has, I think, now been shown that man and the higher 
 animals, especially the Primate's, have some few instincts in 
 common. All have the same senses, intuitions and sensa- 
 tions similar passions, affections and emotions, even the 
 more complex ones, such as jealousy, suspicion, emulation, 
 gratitude and magnanimity; they practice deceit and are 
 revengeful; they are sometimes susceptible to ridicule, and 
 even have a sense of humor; they feel wonder and curiosity; 
 they possess the same faculties of imitation, attention, de- 
 liberation, choice, memory, imagination, the association of 
 ideas and reason, though in very different degrees. The 
 individuals of the same species graduate in intellect from 
 absolute imbecility to high excellence. They are also liable 
 to insanity, though far less often than in the case of man.* 
 Nevertheless, many authors have insisted that man is 
 divided by an insuperable barrier from all the lower animals 
 in his mental faculties. I formerly made a collection of 
 above a score of such aphorisms, but they are almost worth- 
 less, as their wide difference and number prove the diffi- 
 culty, if not the impossibility, of the attempt. It has been 
 asserted that man alone is capable of progressive improve- 
 ment; that he alone makes use of tools or fire, domesticates 
 other animals, or possesses property; that no animal has the 
 power of abstraction or of forming general concepts, is self- 
 conscious and comprehends itself; that no animal employs 
 language; that man alone has a sense of beauty, is liable to 
 caprice, has the feeling of gratitude, mystery, etc. ; believes 
 in God, or is endowed with a conscience. I will hazard a 
 few remarks on the more important and interesting of these 
 points. 
 
 Archbishop Sumner formerly maintainedf that man 
 alone is capable of progressive improvement. That he is 
 capable of incomparably greater and more rapid improve- 
 
 have been drawn, seem to us to rest upon no better foundation than 
 a great many other metaphysical distinctions ; that is, the assumption 
 that because you can give two things different names, they must 
 therefore have different natures. It is difficult to understand how 
 anybody who has ever kept a dog, or seen an elephant, can have any 
 doubts as to an animal's power of performing the essential processes 
 of reasoning." 
 
 *See "Madness in Animals," by Dr. W. Lauder Lindsay, iu 
 "Journal of Mental Science," July, 1871. 
 
 fQuoted by Sir C. Lyell, " Antiquity of Man," p. 497.
 
 90 THE DESCENT OF MAN. 
 
 ment than is any other animal, admits of no dispute; and 
 this is mainly due to his .power of speaking and handing 
 down his acquired knowledge. With animals,, looking first 
 to the individual, every one who has had any experience in 
 setting traps, knows that young animals can be caught 
 much more easily than old ones; and they can be much 
 more easily approached by an enemy. Even with respect 
 to old animals, it is impossible to catch many in the same 
 place and in the same kind of trap, or to destroy them by 
 the same kind of poison ; yet it is improbable that all 
 should have partaken of the poison, and impossible that all 
 should have been caught in a trap. They must learn cau- 
 tion by seeing their brethren caught or poisoned. In North 
 America, where the fur-bearing animals have long been pur- 
 sued, they exhibit, according to the unanimous testimony of 
 all observers, an almost incredible amount of sagacity, caution 
 and cunning; but trapping has been there so long carried 
 on that inheritance may possibly have come into play. I 
 have received several accounts that when telegraphs are first 
 Bet up in any district many birds kill themselves by flying 
 against the wires, but that in the course of a few years they 
 learn to avoid this danger by seeing, as it would apuear, 
 their comiades killed.* 
 
 If we look to successive generations, or to the race, there 
 is no doubt that birds and other animals gradually both 
 acquire and lose caution in relation to man or other enemies;! 
 and this caution is certainly in chief part an inherited 
 habit or instinct, but in part the result of individual expe- 
 rience. A good observer, Leroy,J states that in districts 
 where foxes are much hunted the young, on first leaving 
 their burrows, are incontestably much more wary than the 
 old ones in districts where they are not much disturbed. 
 
 Our domestic dogs are descended from wolves and jackals, 
 and though they may not have gained in cunning, and may 
 
 *For additional evidence, with details, see M. Houzea". "Les 
 Facultes Mentales," torn, ii, 1872, p. 147. 
 
 f See, with respect to birds on oceanic islands, my "Journal of 
 Researches during the voyage of the ' Beagle,' " 1845, p. 398. " Ori- 
 gin of Species," 5th edition, p. 260. 
 
 i"Lettres Phil, eur 1'Intelligence des Anirnaux," nouvelle edit., 
 1802, p. 86. 
 
 See the evidence on this head in chap, i, vol. i, M On the Varia- 
 tion of Animals and Plants under Domestication."
 
 MENTAL POWERS. 91 
 
 have lost in wariness and suspicion, yet they have pro- 
 gressed in certain moral qualities, such as in affection, trust- 
 worthiness, temper and probably in general intelligence. 
 The common rat has conquered and beaten several other 
 species throughout Europe, in parts of North America, 
 New Zealand, and recently in Formosa, as well as on the 
 mainland of China. Mr. Swinhoe,* who describes these 
 two latter cases, attributes the victory of the common rat 
 over the large Mus coninga to its superior cunning; and 
 this latter quality may probably be attributed to the habit- 1 
 ual exercise of all its faculties in avoiding extirpation by 
 man, as well as to nearly all the less cunning or weak- 
 minded rats having been continuously destroyed by him. 
 It is, however, possible that the success of the common rat 
 may be due to its having possessed greater cunning than its 
 fellow-species before it became associated with man. To 
 maintain, independently of any direct evidence, that no 
 animal during the course of ages has progressed in intellect 
 or other mental faculties is to beg the question of the evo- 
 lution of species. We have seen that, according to Lartet, 
 existing mammals belonging to several orders have larger 
 brains than their ancient tertiary prototypes. 
 
 It has often been said that no animal uses any tool; but 
 the chimpanzee in a state of nature cracks a native fruit, 
 somewhat like a walnut, with a stone, f Eengger J easily 
 taught an American monkey thus to break open hard palm- 
 nuts; and afterward of its own accord it used stones to 
 open other kinds of nuts, as well as boxes. It thus also 
 removed the soft rind of fruit that had a disagreeable 
 flavor. Another monlecy was taught to open the lid of a 
 large box with a stick, and afterward it used the stick as a 
 lever to move heavy bodies; and I have myself seen a young 
 orang put a stick into a crevice, slip his hand to the other 
 end, and use it in the proper manner as a lever. The 
 tamed elephants in India are well known to break off 
 branches of trees and use them to drive away the flies; and 
 this same act has been observed in an elephant in a state of 
 
 * "Proc. Zoolog. Boo.," 1864, p. 186. 
 
 f Savage and Wyrnan in "Boston Journal of Nat. Hist.," vol. IT, 
 1843-44, p. 383. 
 
 t "Saugethiere von Paraguay," 1830, s. 51-56.
 
 92 THE DESCENT 0V MAN. 
 
 nature.* I have seen a young orang, when she thought 
 she was going to be whipped, cover and protect herself 
 with a blanket or straw. In these several cases stones and 
 sticks were employed as implements; but they are likewise 
 used as weapons. Brehmf states, on the authority of the 
 well-known traveler Schimper, that in Abyssinia when the 
 baboons belonging to one species ( C. gelada) descend in troops 
 from the mountains to plunder the fields they sometimes 
 encounter troops of another species (G. hamadryas), and 
 then a fight ensues. The Geladas roll down great stones, 
 which the Hamadryas try to avoid, and then both species, 
 making a great uproar, rush furiously against each other. 
 Brehm, when accompanying the Duke of Coburg-Gotha, 
 aided in an attack with firearms on a troop of baboons in 
 the pass of Mensa in Abyssinia. The baboons in return 
 rolled so many stones down the mountain, some as large as 
 a man's head, that the attackers had to beat a hasty retreat; 
 and the pass was actually closed for a time against the 
 caravan. It deserves notice that these baboons thus acted 
 in concert. Mr. WallaceJ on three occasions saw female 
 orangs, accompanied by their young, "breaking off 
 branches and the great spiny fruit of the Durian tree, with 
 every appearance of rage; causing such a shower of missiles 
 as effectually kept us from approaching too near the tree." 
 As I have repeatedly seen, a chimpanzee will throw any 
 object at hand at a person who offends him; and the before- 
 mentioned baboon at the Cape of Good Hope prepared mud 
 for the purpose. 
 
 In the Zoological Gardens a monkey, which had weak 
 teeth used to break open nuts with a stone; and I was 
 assured by the keepers that after using the stone he hid it 
 in the straw, and would not let any other monkey touch it. 
 Here, then, we have the idea of property; but this idea is 
 common to every dog with a bone, and to most or all birds 
 with their nests. 
 
 The Duke of Argyll remarks that the fashioning of an 
 implement for a special purpose is absolutely peculiar to 
 man; and he considers that this forms an immeasurable 
 gulf between him and the brutes. This is no doubt a very 
 
 *The "Indian Field," March 4, 1871. 
 
 f " Thierleben," B. i, s. 79, 82. 
 
 J "The Malay Archipelago," vol. i, 1869, p. 87. 
 
 " Primeval Man," 1869, pp. 145, 147.
 
 MENTAL POWERS. 93 
 
 important distinction; but there appears to me much truth 
 in Sir J. Lubbock's suggestion,* that when primeval man 
 first used flint-stones for any purpose, he would have acci- 
 dentally splintered them, and would then have used the 
 sharp fragments. From this step it would be a small one 
 to break the flints on purpose, and not a very wide step to 
 fashion them rudely. This latter advance, however, may 
 have taken long ages, if we may judge by the immense in- 
 terval of time which elapsed before the men of the neolithic 
 period took to grinding and polishing their stone tools. In 
 breaking the flints, as Sir J. Lubbock likewise remarks, 
 sparks would have been emitted, and in grinding them heat 
 would have been evolved; thus the two usual methods of 
 "obtaining fire may have originated." The nature of fire 
 would have been known in the many volcanic regions where 
 lava occasionally flows through forests. The anthropomor- 
 phous apes, guided probably by instinct, build for them- 
 selves temporary platforms; but as many instincts are largely 
 controlled by reason, the simpler ones, such as this of build- 
 ing a platform, might readily pass into a voluntary and 
 conscious act. The orang is known to cover itself at night 
 with the leaves of the Paudanus; and Brehm states that 
 one of his baboons used to protect itself from the heat of the 
 sun by throwing a straw-mat over its head. In these sev- 
 eral habits, we probably see the fi^et steps toward some of 
 the simpler arts, such as rude architecture and dress, as 
 they arose among the early progenitors of man. 
 
 Abstraction, General Conceptions, Self -consciousness, 
 Mental Individuality. It would be very difficult for any 
 one with even much more knowledge than I possess to de- 
 termine how far animals exhibit any traces of these high 
 mental powers. This difficulty arises from the impossibility 
 of judging what passes through the mind of an animal; 
 and again, the fact that writers differ to a great extent in 
 the meaning which they attribute to the above terms, 
 causes a further difficulty. If one may judge from 
 various articles which have been published lately, the great- 
 est stress seems to be laid on the supposed entire absence 
 in animals of the power of abstraction, or of forming general 
 concepts. But when a dog sees another dog at a distance, 
 
 * " Prehistoric Times," 1865, p. 473, etc.
 
 94 THE DESCENT OF MAN. 
 
 it is often clear that he perceives that it is a dog in the 
 abstract; for when he gets nearer his whole manner sud- 
 denly changes, if the other dog be a friend. A recent 
 writer remarks, that in all such cases it is a pure assump- 
 tion to assert that the mental act is not essentially of the 
 same nature in the animal as in man. If either refers what 
 he perceives with his senses to a mental concept, then so do 
 both.* When I say to my terrier, in an eager voice (and I 
 have made the trial many times), " Hi, hi, where is it?" she 
 at once takes it as a sign that something is to be hunted, 
 and generally first looks quickly all around, and then 
 rushes into the nearest thicket, to scent for any game, but 
 finding nothing, she looks up into any neighboring tree for 
 a squirrel. Now do not these actions clearly show that she 
 had in her mind a general idea or concept that some ani- 
 mal is to be discovered and hunted? 
 
 It may be freely admitted that no animal is self -conscious, 
 if by this term it is implied, that he reflects on such points, 
 as whence he comes or whither he will go, or what is life 
 and death, and so forth. But how can we feel sure that 
 an old dog with an excellent memory and some power of 
 imagination, as shown by his dreams, never reflects on his 
 past pleasures or pains in the chase? And this would be a 
 form of self-consciousness. On the other hand, as Biichnerf 
 has remarked, how little can the hard-worked wife of a de- 
 graded Australian savage, who uses very few abstract words, 
 and cannot count above four, exert her self -consciousness, 
 or reflect on the nature of her own existence. It is gener- 
 ally admitted that the higher animals possess memory, at- 
 tention, association, and even some imagination and reason. 
 If these powers, which differ much in different animals, are 
 capable of improvement, there seems no great improbability 
 in more complex faculties, such as the higher forms of ab- 
 straction, and self -consciousness, etc., having been evolved 
 through the development and combination of the simpler 
 ones. It has been urged against the views here maintained 
 that it is impossible to say at what point in the ascending 
 scale animals become capable of abstraction, etc. ; but who 
 can say at what age this occurs in our young children? 
 
 *Mr. Hookham, in a letter to Prof. Max Muller, in the "Birm- 
 ingham News," May 1873. 
 
 {"Conferences sur la Theorie Darwinienne," French translat.. 
 1869, p. 132.
 
 MENTAL POWERS. 95 
 
 We see at least that such powers are developed in children 
 by imperceptible degrees. 
 
 That animals retain their mental individuality is unques- 
 tionable. When my voice awakened a train of old associa- 
 tions in the mind of the before-mentioned dog, he must 
 have retained his mental individuality, although every atom 
 of his brain had probably undergone change more than 
 once during the interval of five years. This dog might 
 have brought forward the argument lately advanced to 
 crush all evolutionists, and said: "I abide amid all mental 
 moods and all material changes. . . . The teaching 
 that atoms leave their impressions as legacies to other atoms 
 falling into the places they have vacated is contradictory of 
 the utterance of consciousness, and is therefore false; but it 
 is the teaching necessitated by evolutionism, consequently 
 the hypothesis is a false one." * 
 
 Language. This faculty has justly been considered as 
 one of the chief distinctions between man and the lower 
 animals. But man, as a highly competent judge, 
 Archbishop Whately remarks, " is not the only animal that 
 can make use of language to express what is passing in his 
 mind, and can understand, more or less, what is so ex- 
 pressed by another. "f In Paraguay the Cebus azarce when 
 excited utters at least six distinct sounds, which excite in 
 other monkeys similar emotions. J The movements of the 
 features and gestures of monkeys are understood by us, and 
 they partly understand ours, as Rengger and others declare. 
 It is a more remarkable fact that the dog, since being 
 domesticated, has learned to bark in at least four or five 
 distinct tones. Although barking is a new art, no doubt 
 the wild parent-species of the dog expressed their feelings 
 by cries of various kinds. With the domesticated dog we 
 have the bark of eagerness, as in the chase; that of anger, 
 as well as growling; the yelp or howl of despair, as when 
 shut up; the baying at night; the bark of joy, as when 
 starting on a walk with his master; and the very distinct 
 
 *The Rev. Dr. J. M'Cann, " Anti-Darwinism," 1869, p. 13. 
 f Quoted in " Anthropological Review," 1864, p. 158. 
 j Rengger, ibid, s. 45. 
 
 S See my " Variation of Animals and Plants under Domestication," 
 vol. i, p. 27.
 
 96 THE DESCENT OF MAN. 
 
 one of demand or supplication, as when wishing for a door 
 or window to be opened. According to Houzeau, who paid 
 particular attention to the 'subject, the domestic fowl utters 
 at least a dozen significant sounds.* 
 
 The habitual use of articulate language is, however, 
 peculiar to man; but he uses, in common with the lower 
 animals, inarticulate cries to express his meaning, aided by 
 gestures and the movements of the muscles of the face, f 
 This specially holds good with the more simple and vivid 
 feelings, which are but little connected with our higher 
 intelligence. Our cries of pain, fear, surprise, anger, to- 
 gether with their appropriate actions, and the murmur of a 
 mother to her beloved child, are more expressive than any 
 words. That which distinguishes man from the lower ani- 
 mals is not the understanding of articulate sounds, for, as 
 every one knows, dogs understand many words and sen- 
 tences. In this respect they are at the same stage of devel- 
 opment as infants, between the ages of ten and twelve 
 months, who understand many words and short sentences, 
 but cannot yet utter a single word. It is not the mere ar- 
 ticulation which is our distinguishing character, for parrots 
 and other birds possess this power. Nor is it the mere 
 capacity of connecting definite sounds with definite ideas; 
 for it is certain that some parrots, which have been taught 
 to speak, connect unerringly words with things and per- 
 sons with events. J The lower animals differ from man 
 
 * "Facultes Mentales des Animaux," toin. ii, 1872, pp. 346-349. 
 
 \ See a discussion on this subject in Mr. E. B. Tylor's very inter- 
 esting work, " Researches into the Early History of Mankind," 1865, 
 chaps, ii to iv. 
 
 1 1 have received several detailed accounts to this effect. Admiral 
 Sir B. J. Sulivan, whom I know to be a careful observer, assures me 
 that an African parrot, long kept in his father's house, invariably 
 called certain persons of the household, as well as visitors, by their 
 names. He said "good morning" to every one at breakfast, and 
 "good night" to each as they left the room at night, and never re- 
 versed these salutations. To Sir B. J. Sulivan's father, he used to 
 add to the " good morning" a short sentence, which was never once 
 repeated after his father's death. He scolded violently a strange 
 dog which came into the room through the open window; and he 
 scolded another parrot (saying "you naughty polly ") which had got 
 out of its cage, and was eating apples on the kitchen table. See 
 also, to the same effect, Houzeau on parrets, " Facultes Mentales," 
 torn, ii, p. 309. Dr. A. Moschkau informs me that he knew a star- 
 ling which never made a mistake in saying in German " good morn- 
 ing " to persons arriving, and " good-by, old fellow," to those de- 
 parting. I could add several, other such cases.
 
 MTENTAL POWERS. 97 
 
 solely in his almost infinitely larger power of associating 
 together the most diversified sounds and ideas, and this 
 obviously depends on the high development of his mental 
 powers. 
 
 As Home Tooke, one of the founders of the noble science 
 of philology, observes, language is an art, like brewing or 
 baking; but writing would have been a better simile. It 
 certainly is not a true instinct, for every language has to be 
 learned. It differs, however, widely from all ordinary arts, 
 for man has an instinctive tendency to speak, as we see in 
 the babble of our young children; while no child has an 
 instinctive tendency to brew, bake, or write. Moreover, no 
 philologist now supposes that any language has been delib- 
 erately invented; it has been slowly and unconsciously de- 
 veloped by many steps.* The sounds uttered by birds 
 offer in several respects the nearest analogy to language, 
 for all the members of the same species utter the same in- 
 stinctive cries expressive of their emotions; and all the 
 kinds which sing exert their power instinctively; but the 
 actual song, and even the call-notes, are learned from their 
 parents or foster-parents. These sounds, as Daines Bar- 
 ringtonf has proved, "are no more innate than language 
 is in man." The first attempts to sing "may be compared 
 to the imperfect endeavor in a child to babble." The 
 young males continue practicing, or as the bird-catchers 
 say, "recording," for ten or eleven months. Their first 
 essays show hardly a rudiment of the future song; but as 
 they grow older we can perceive what they are aiming at; 
 and at last they are said " to sing their song round." 
 Nestlings which have learned the song of a distinct species, 
 as with the canary birds educated in the Tyrol, teach and 
 transmit their new song to their offspring. The slight 
 natural differences of song in the same species inhabiting 
 different districts may be appositely compared, as Barring- 
 
 * See some good remarks on this head by Prof. Whitney, in his 
 " Oriental and Linguistic Studies," 1873, p. 354. He observes that 
 the desire of communication between man is the living force, which, 
 in the development of language, "works both consciously and un- 
 consciously; consciously as regards the immediate end to be attained; 
 unconsciously as regard's the further consequences of the act." 
 
 f Hon. Daines Barrington in "Philosoph. Transactions," 1773, p. 
 262. See also Dureau de la Malle, in "Ann. des. Sc. Nat.," 3d 
 series, Zoolog. torn, x, p. 119.
 
 98 THE DESCENT OF MAN. 
 
 ton remarks, "to provincial dialects ;" and the songs of 
 allied though distinct spepies may be compared with the 
 languages of distinct races of man. I have given the fore- 
 going details to show that an instinctive tendency to 
 acquire an art is not peculiar to man. 
 
 With respect to the origin of articulate language, after 
 having read on the one side the highly interesting works of 
 Mr. Hensleigh Wedgwood, the Rev. F. Farrar, and Prof. 
 Schleicher,* and the celebrated lectures of Prof. Max Mul- 
 ler on the other side, I cannot doubt that language owes its 
 origin to the imitation and modification of various natural 
 sounds, the voices of other animals and man's own instinctive 
 cries, aided by signs and gestures. W~hen we treat of sexual 
 selection we shall see that primeval man, or rather some 
 early progenitor of man, probably first used his voice in 
 producing true musical cadences, that is in singing, as do 
 some of the gibbon-apes at the present day; and we may 
 conclude from a widely-spread analogy, that this power 
 would have been especially exerted during the courtship of 
 the sexes would have expressed various emotions, such as 
 love, jealousy, triumph and would have served as a chal- 
 lenge to rivals. It is, therefore, probable that the imita- 
 tion of musical cries by articulate sounds may have given 
 rise to words expressive of various complex emotions. The 
 strong tendency in our nearest allies, the monkeys, in 
 microcephalous idiots, f and in the barbarous races of" man- 
 kind, to imitate whatever they hear deserves notice, as 
 bearing on the subject of imitation. Since monkeys cer- 
 tainly understand much that is said to them by man, and 
 when wild utter signal-cries of danger to their fellows; \ 
 and since fowls give distinct warnings for danger on the 
 ground, or in the sky from hawks (both, as well as a third 
 
 * " On the Origin of Language," by H. Wedgwood, 1866. " Chap- 
 ters 011 Language," bj the Rev. F. W. Farrar, 1865. These works 
 are most interesting. See also "De la Phys. et de Parole," par 
 Albert Lemoine, 1865, p. 190. The work on this subject, by the late 
 Prof. Aug. Schleicher has been translated by Dr. Bikkers into En- 
 glish, under the title of " Darwinism tested hy the Science of Lan 
 guage," 1869. 
 
 fVogt, "Memoire sur les Microcephales," 1867, p. 169. With 
 respect to savages, I have given some facts in iny "Journal of Re- 
 searches," etc., 1845, p. 206. 
 
 J See clear evidence on this head in the two works so often quoted, 
 by Brehm and Rengger.
 
 MENTAL POWERS. 99 
 
 cry, intelligible to dogs*), may not some unusually wise 
 ape-like animal have imitated the growl of a beast of prey, 
 and thus told his fellow-monkeys the nature of the expected 
 danger? This would have been a first step in the forma- 
 tion of a language. 
 
 As the voice was used more and more, the vocal organs 
 would have been strengthened and perfected through the 
 principle of the inherited effects of use; and this would 
 have reacted on the power of speech. But the relation be- 
 tween the continued vise of language and the development 
 of the brain, has no doubt been far more important. The 
 mental powers in some early progenitor of man must have 
 been more highly developed than in any existing ape, 
 before even the most imperfect form of speech could have 
 come into use; but we may confidently believe that the 
 continued use and advancement- of this power would have 
 reacted on the mind itself, by enabling and encouraging it 
 to carry on long trains of thought. A complex train of 
 thought can no more be carried on without the aid of 
 words, whether spoken or silent, than a long calculation 
 without the use of figures or algebra. It appears, also, 
 that even an ordinary train of thought almost requires, or 
 is greatly facilitated by some form of language, for the 
 dumb, deaf, and blind girl, Laura Briclgman, was observed 
 to use her fingers while dreaming, f Nevertheless, a long 
 succession of vivid and connected ideas may pass "through 
 the mind without the aid of any form of language, as we 
 may infer from the movements of dogs during their 
 dreams. We have, also, seen that animals are able to 
 reason to a certain extent, manifestly without the aid of 
 language. The intimate connection between the brain, as 
 it is now developed in us, and the faculty of speech, is 
 well shown by those curious cases of brain-disease in which 
 speech is specially affected, as when the power to remem- 
 ber substantives is lost, while other words can be correctly 
 used, or where substantives of a certain class, or all 
 except the initial letters of substantives and proper 
 
 * Houzeau gives a very curious account of his observations on this 
 subject in his " Facultes Mentales des Animaux," torn, ii, p. 348. 
 
 4 See remarks on this head by Dr. Maudsley, " The Physiology 
 and Pathology of Mind," 2d edit., 1868* o. 199.
 
 100 THE DESCENT OF MAN. 
 
 names are forgotten.* There is no more improbability in 
 continued use of the mental and vocal organs leading to 
 inherited changes in their structure and functions, than in 
 the case of handwriting, which depends partly on the form 
 of the hand and partly on the disposition of the mind; and 
 handwriting is certainly inherited, f 
 
 Several writers, more especially Prof. Max Miiller,J havo 
 lately insisted that the use of language implies the power of 
 forming general concepts; and that as no animals are sup- 
 posed to possess this power, an impassable barrier is formed 
 between them and man. With respect 'to animals, I have 
 already endeavored to show that they have this power, at 
 least in a rude and incipient degree. As far as concerns 
 infants of from ten to eleven months old, and deaf-mutes, 
 it seems to me incredible that they should be able to con- 
 nect certain sounds with certain general ideas as quickly as 
 they do, unless such ideas were already formed in their 
 minds. The same remark may be extended to the more 
 intelligent animals; as Mr. Leslie Stephen observes, || "A 
 
 * Many curious cases have been recorded. See, for instance, Dr. 
 Bateman, " On Aphasia," 1870, pp. 27, 31, 53, 100, etc. Also, " In- 
 quiries Concerning the Intellectual Powers," by Dr. Abercrombie, 
 1838, p. 150. 
 
 f " The Variation of Animals and Plants under Domestication," 
 Tol. ii, p. 6. 
 
 \ Lectures on "Mr. Darwin's Philosophy of Language," 1873. 
 
 The judgment of a distinguished philologist, such as Prof. Whit- 
 ney, will have far more weight on this point than anything that I 
 can say. He remarks ("Oriental and Linguistic Studi'es," 1873, p. 
 297), in speaking of Bleek's views: "Because on the grand scale 
 language is the necessary auxiliary of thought, indispensable to the 
 development of the power of thinking, to the distinctness and variety 
 and complexity of cognitions to the full mastery of consciousness; 
 therefore he would fain make thought absolutely impossible without 
 speech, identifying the faculty with its instrument. He might just 
 as reasonably assert that the human hand cannot act without a tool. 
 With such a doctrine to start from, he cannot stop short of Miiller's 
 worst paradoxes, that an infant (in fans, not speaking) is not a 
 human being, and that deaf-mutes do not become possessed of reason 
 until they learn to twist their fingers into imitation of spoken 
 words." Max Miiller gives in italics (" Lectures on Mr. Darwin's 
 Philosophy of Language," 1873, third lecture) the following aphor- 
 ism: " There is no thought without words, as little as there are 
 words without thought." What a strange definition must here be 
 given to the word thought. 
 , J Essays on Free-thinking," etc., 1873, p. 82.
 
 MENTAL POWERS. 101 
 
 dog frames a general concept of cats or sheep, and knows 
 the corresponding words as well as a philosopher. And the 
 capacity to understand is as good a proof of vocal intelli- 
 gence, though in an inferior degree, as the capacity to 
 speak." 
 
 Why the organs now used for speech should have been 
 originally perfected for thi: purpose, rather than any other 
 organs, it is not difficult to see. Ants have considerable 
 powers of intercommunication, by means of their antennae, 
 as shown by Huber, who devotes a whole chapter to their 
 language. We might have used our fingers as efficient in- 
 struments, for a person with practice can report to a deaf man 
 every word of a speech rapidly delivered at a public meeting; 
 but the loss of our hands while thus employed would have 
 been a serious inconvenience. As all the higher mammals 
 possess vocal organs, constructed on the same general plan as 
 ours, and used as a means of communication, it was ob- 
 viously probable that these same organs would be still further 
 
 the higher apes not using their vocal organs for speech, no 
 doubt depends on their intelligence not having been suffi- 
 ciently advanced. The possession by them of organs, which 
 with long-continued practice might have been used for 
 speech, although not thus used, is paralleled by the case of 
 many birds which possess organs fitted for singing, though 
 they never sing. Thus, the nightingale and crow have 
 vocal organs similarly constructed, these being used by the 
 former for diversified song, and by the latter only for croak- 
 ing, f If it be asked why apes have not had their intellects 
 developed to the same degree as that of man, general causes 
 only can be assigned in answer, and it is unreasonable to 
 expect anything more definite, considering our ignorance 
 
 *See some good remarks to this effect by Dr. Maudsley, "The 
 Physiology and Pathology of Mind," 1868, p.* 199. 
 
 f Macgillivray, "Hist, of British Birds," vol. ii, 1839, p. 29. An 
 excellent observer, Mr. Black wall, remarks that the magpie learns to 
 pronounce single words, and even short sentences, more readily than 
 almost any other British bird; yet, as he adds, after long and closely 
 investigating its habits, he has never known it, in a state of natuare, 
 display any unusual capacity for imitation. " Researches in Zool- 
 ogy," 1834, p. 158.
 
 102 THE DESCENT OF MAN. 
 
 with respect to the successive stages of development through 
 which each creature has passed. 
 
 The formation of different languages and of distinct 
 species, and the proofs that both have been developed 
 through a gradual process, are curiously parallel.* But we 
 can trace the formation of many words further back than 
 that of species, for we can perceive how they actually arose 
 from the imitation of various sounds. We find in distinct 
 languages striking homologies due to community of de- 
 scent, and analogies due to a similar process of formation. 
 The manner in which certain letters or sounds change 
 when others change is very like correlated growth. We 
 have in both cases the reduplication of parts, the effects of 
 long-continued use, and so forth. The frequent presence 
 of rudiments, both in languages and in species, is still more 
 remarkable. The letter m in the word am, means I; so 
 that in the expression 7 am, a superfluous and useless rudi- 
 ment has been retained. In the spelling also of words, let- 
 ters often remain as the rudiments of ancient forms of pro- 
 nunciation. Languages, like organic beings, can be classed 
 in groups under groups; and they can be classed either nat- 
 urally according to descent, or artificially by other charac- 
 ters. Dominant languages and dialects spread widely, and 
 lead to the gradual extinction of other tongues. A lan- 
 guage like a species, when once extinct, never, as Sir 0. Lyell 
 remarks, reappears. The same language never has two 
 birth-places. Distinct languages may be crossed or blended 
 together.f We see variability in every tongue, and new 
 words are continually cropping up; but as there is a limit 
 to the powers of the memory, single words, like whole lan- 
 guages, gradually become extinct. As Max MiillerJ; has 
 well remarked: " A struggle for life is constantly going on 
 among the words and grammatical forms in each language. 
 The better, the shorter, the easier forms are constantly 
 gaining the upper hand, and they owe their success to their 
 own inherent virtue. " To these more important causes of 
 
 * See the very interesting parallelism between the development of 
 species and languages, given by Sir C. Lyell in "The Geolog. Evi- 
 dences of the Antiquity of Man," 1863, chap, xxiii. 
 
 f See remarks to this effect by the Rev. P. W. Farrar, in an inter- 
 esting article, entitled " Philology and Darwinism," in " Nature^* 
 March 24, 1870, p. 528. 
 
 t " Nature," Jan. 6, 1870, p. 257.
 
 MENTAL POWERS. 103 
 
 the survival of certain words mere novelty and fashion may 
 be added; for there is in the mind of man a strong love for 
 slight changes in all things. The survival or preservation 
 of certain favored words in the struggle for existence is 
 natural selection. 
 
 The perfectly regular and wonderfully complex con- 
 struction of the languages of many barbarous nations has 
 often been advanced as a proof, either of the divine origin 
 of these languages, or of the high art and former civiliza- 
 tion of their founders. Thus F. von Schlegel writes: "In 
 those languages which appear to be at the lowest grade of 
 intellectual culture, we frequently observe a very high and 
 elaborate degree of art in their grammatical structure. This 
 is especially the case with the Basque and' the Lapponian, 
 and many of the American languages."* But it is assuredly 
 an error to speak of any language as an art, in the sense of 
 its having been elaborately and methodically formed. Philol- 
 ogists now admit that conjugations, declensions, etc., 
 originally existed as distinct words, since joined together ; 
 and as such words express the most obvious relations be- 
 tween objects and persons, it is not surprising that they 
 should have been used by the men of most races during the 
 earliest ages. With respect to perfection, the following 
 illustration will best show how easily we may en-; a Crinoid 
 sometimes consists of no less than 150,000 pieces of shell, f 
 all arranged with perfect symmetry in radiating lines; but 
 a naturalist does not consider an animal of this kind as 
 more perfect than a bilateral one with comparatively few 
 parts, and with none of these parts alike, excepting on the 
 opposite sides of the body. He justly considers the differ- 
 entiation and specialization of organs as the test of perfec- 
 tion. So with languages; the most symmetrical and com- 
 plex ought not to be ranked above irregular, abbreviated, 
 and bastardized languages, which have borrowed expressive 
 words and useful forms of construction from various con- 
 quering, conquered or immigrant races. 
 
 From these few and imperfect remarks I conclude that 
 the extremely complex and regular construction of many 
 barbarous languages is no proof that they owe their origin 
 
 * Quoted by C. S Wake, " Chapters on Man," 1868, p. 101 
 f Buckland, " Bridgewater Treatise," p. 411.
 
 104 THE DESCENT OF MAN. 
 
 to a special act of creation.* Nor, as we have seen, does 
 the faculty of articulate speech in itself offer any insuper- 
 able objection to the beliei that man has been developed 
 from some lower form. 
 
 Sense of Beauty. This sense has been declared to be 
 peculiar to man. I refer here only to the pleasure given by 
 certain colors, forms and sounds, and which may fairly be 
 called a sense of the beautiful; with cultivated men such 
 sensations are, however, intimately associated with complex 
 ideas and trains of thought. When we behold a male bird 
 elaborately displaying his graceful plumes or splendid colors 
 before the female, while other birds, not thus decorated, 
 make no such display, it is impossible to doubt that she 
 admires the beauty of her male partner. As women every- 
 where deck themselves with these plumes, the beauty of 
 such ornaments cannot be disputed. As we shall see later, 
 the nests of humming-birds, and the playing passages of 
 bower-birds are tastefully ornamented with gayly-colored ob- 
 jects; and this shows that they must receive some kind of pleas- 
 ure from the sight of such things. With the great majority 
 of animals, however, the taste for the beautiful is confined, 
 as far as we can judge, to the attractions of the opposite 
 sex. The sweet strains poured forth by many male birds 
 during the season of love are certainly admired by the 
 females, of which fact evidence will hereafter be given. If 
 female birds had been incapable of appreciating the beauti- 
 ful colors, the ornaments and voices of their male partners, 
 all the labor and anxiety exhibited by the latter iu display- 
 ing their charms before the females would have been thrown 
 away; and this it is impossible to admit. Why certain 
 bright colors should excite pleasure cannot, I presume, be 
 explained any more than why certain flavors and scents are 
 agreeable; but habit has something to do with the result, 
 for that which is at first unpleasant to our senses ultimately 
 becomes pleasant, and habits are inherited. With respect 
 to sounds, Helmholtz has explained to a certain extent on 
 physiological principles why harmonies and certain cadences 
 are agreeable. But besides this, sounds frequently recur- 
 ring at irregular intervals are highly disagreeable, as every 
 
 * See some good remarks on the simplification of languages, by 
 Sir J. Lubbock, " Origin of Civilization," 1870, p. 278.
 
 MENTAL POWERS. 105 
 
 one will admit who has listened at night to the irregular 
 napping of a rope on board ship. The same principle seems 
 to come into play with vision, as the eye prefers symmetry 
 or figures with some regular recurrence. Patterns of this 
 kind are employed by even the lowest savages as ornaments; 
 and they have been developed through sexual selection for 
 the adornment of some male animals. Whether we can or 
 not give any reason for the pleasure thus derived from vision 
 and hearing, yet man and many of the lower animals are 
 alike pleased by the same colors, graceful shading and 
 forms, and the same sounds. 
 
 The taste for the beautiful, at least as far as female 
 beauty is concerned, is not of a special nature in the human 
 mind; for it differs widely in the different races of man, 
 and is not quite the same even in the different nations of 
 the same race. Judging from the hideous ornaments and 
 the equally hideous music admired by most savages, it might 
 be urged that their aesthetic faculty was not so highly de- 
 veloped as in certain animals, for instance, as in birds. 
 Obviously no animal would be capable of admiring such 
 scenes as the heavens at night, a beautiful landscape, or 
 refined music; but such high tastes are acquired through 
 culture, and depend on complex associations; they are not 
 enjoyed by barbarians or by uneducated persons. 
 
 .Many of the faculties which have been of inestimable 
 service to man for his progressive advancement, such as the 
 powers of the imagination, wonder, curiosity, an undefined 
 sense of beauty, a tendency to imitation, and the love of 
 excitement or novelty, could hardly fail to lead to capricious 
 changes of customs and fashions. I have alluded tc this 
 point because a recent writer* has oddly fixed on Caprice 
 " as one of the most remarkable and typical differences be- 
 tween savages and brutes." But not only can we partially 
 understand how it is that man is from various conflicting 
 influences rendered capricious, but that the lower animals 
 are, as we shall hereafter see, likewise capriciousi in their 
 affections, aversions, and sense of beauty. There is also 
 reason to suspect that they love novelty for its own sake. 
 
 Belief in God Religion. There is no evidence that 
 man was aboriginally endowed Avith the ennobling belief in 
 
 * " The Spectator." Dec. 4, 1869, p. 1430.
 
 106 THE DESCENT OF MAN. 
 
 the existence of an Omnipotent God. On the contrary 
 there is ample evidence, derived not from hasty travelers, 
 but from men who have long resided with savages, that 
 numerous races have existed, and still exist, who have no 
 idea of one or more gods, and who have no words in their 
 languages to express such an idea.* The question is of 
 course wholly distinct from that higher one, whether there 
 exists a Creator and Ruler of the universe; and this has 
 been answered in the affirmative by some of the highest 
 intellects that have ever existed. 
 
 If, however, we include under the term "religion" the 
 belief in unseen or spiritual agencies, the case is wholly 
 different; for this belief seems to be universal with the less 
 civilized races. Nor is it difficult to comprehend how it 
 arose. As soon as the important faculties of the imagina- 
 tion, wonder, and curiosity, together with some power of 
 reasoning, had become partially developed, man would 
 naturally crave to understand what was passing around him, 
 and would have vaguely speculated on his own existence. 
 As Mr. M'Lennan f has remarked, ' ' Some explanation of 
 the phenomena of life, a man must feign for himself, and 
 to judge from the universality of it, the simplest hypothe- 
 sis, and the first to occur to men, seems to have been that 
 natural phenomena are ascribable to the presence in 
 animals, plants, and things, and in the forces of nature, of 
 such spirits prompting to action as men are conscious they 
 themselves possess." It is also probable, as Mr. Tylor has 
 shown, that dreams may have first given rise to the notion 
 of spirits; for savages do not readily distinguish between 
 subjective and objective impressions. When a savage 
 dreams, the figures which appear before him are believed to 
 have come from a distance, and to stand over him; or " the 
 soul of the dreamer goes out on its travels, and comes 
 home with a remembrance of what it has seen." J But 
 
 * See an excellent article on this subject by the Rev. F. W. Farrar, 
 in the "Anthropological Review," Aug., 1864, p. 217. For fur- 
 ther facts see Sir J. Lubbock, "Prehistoric Times," 2d edit., 1869, p. 
 564; and especially the chapters on Religion in his " Origin of Civil- 
 ization," 1870. 
 
 f " The Worship of Animals and Plants," in the "Fortnightly Re- 
 view," Oct. 1, 1869, p. 422. 
 
 f Tylor, "Early History of Mankind," 1865, p. 6. See also the 
 three striking chapters on the Development of Religion, in Lub- 
 bock'n " Origin of Civilization," 1870. In a like manner Mr. Herbert
 
 MENTAL POWERS. 107 
 
 until the faculties of imagination, curiosity, reason, etc., 
 had been fairly well developed in the mind of man, his 
 dreams would not have led him to believe in spirits, any 
 more than in the case of a dog. 
 
 The tendency in savages to imagine that natural objects 
 and agencies are animated by spiritual or living essences, is 
 perhaps illustrated by a little fact which I once noticed: 
 my dog, a full-grown and very sensible animal, was lying 
 on the lawn during a hot and still day; but at a little dis- 
 tance a slight breeze occasionally moved an open parasol, 
 which would have been wholly disregarded by the dog had 
 any one stood near it. As it was, every time that the par- 
 asol slightly moved the dog growled fiercely and barked. 
 He must, I think, have reasoned to himself in a rapid and 
 unconscious manner that movement without any apparent 
 cause indicated the presence of some strange living agent, 
 and that no stranger had a right to be on his territory. 
 
 The belief in spiritual agencies would easily pass into the 
 belief in the existence of one or more gods. For savages 
 would naturally attribute to spirits the same passions, the 
 same love of vengeance or simplest form of justice, and the 
 same affections which they themselves feel. The Fuegians 
 appear to be in this respect in an intermediate condition, 
 for when the surgeon on board the "Beagle" shot some 
 young ducklings as specimens York Minster declared in 
 the most solemn manner: " Oh, Mr. Bynoe, much rain, 
 much snow, blow much;" and this was evidently a retribu- 
 tive punishment for wasting human food. So again he 
 related how, when his brother killed a " wild man," storms 
 long raged, much rain and snow fell. Yet we could never 
 
 Spencer, in his ingenious essay in the " Fortnightly Review " (May 
 1, 1870, p. 535), accounts for the earliest forms of religious belief 
 throughout the world, by man being led through dreams, shadows, 
 and other causes, to look at himself as a double essence, corporeal 
 and spiritual. As the spiritual being is supposed to exist after death 
 and to be powerful, it is propitiated by various gifts and ceremonies, 
 and its aid invoked. He then further shows that names or nick- 
 names given from some animal or other object, to the early progeni- 
 tors or founders of a tribe, are supposed after a long interval to rep- 
 resent the real progenitor of the tribe; and such animal or object is 
 then naturally believed still to exist as a spirit, is held sacred, and 
 worshiped as a god. Nevertheless I cannot but suspect that there is 
 a still earlier and ruder stage, when anything which manifests 
 power or movement is thought to be endowed with some form of 
 life, and with mental faculties inalajrous to our own.
 
 10S THE DESCENT OF MAN. 
 
 discover that the Fuegians believed in what we should call a 
 God or practiced any religious rites; and Jemmy Button, 
 with justifiable pride, stoutly maintained that there was no 
 devil in his land. This latter assertion is the more remark- 
 able, as with savages the belief in bad spirits is far more 
 common than that in good ones. 
 
 The feeling of religious devotion is a highly complex 
 one, consisting of love, complete submission to an exalted 
 and mysterious superior, a strong sense of dependence,* 
 fear, reverence, gratitude, hope for the future, and per- 
 haps other elements. No being could experience so com- 
 plex an emotion until advanced in his intellectual and 
 moral faculties to at least a moderately high level. Never- 
 theless, we see some distant approach to this state of mind 
 in the deep love of a dog for his master, associated with 
 complete submission, some fear, and perhaps other feelings. 
 The behavior of a dog when returning to his master after 
 an absence, and, as I may add, of a monkey to his beloved 
 keeper, is widely different from that toward their fellows. 
 In the latter case the transports of joy appear to be some- 
 what less, and the sense of equality is shown in every 
 action. Prof. Braubach goes so far as to maintain that a 
 dog looks on his master as on a god.f 
 
 The same high mental faculties which first led man to 
 believe in unseen spiritual agencies, then in fetichism, 
 
 n theism, and ultimately in monotheism, would infallibly 
 him, as long as his reasoning powers remained poorly 
 developed, to various strange superstitions and customs. 
 Many of these are terrible to think of such as the sacrifice 
 of human beings to a blood-loving god; the trial of inno- 
 cent persons by the ordeal of poison or fire, witchcraft, 
 etc. yet it is well occasionally to reflect on these supersti- 
 tions, for they show us what an infinite debt of gratitude 
 we owe to the improvement of our reason, to science, and 
 to our accumulated knowledge. As Sir J. LubbockJ has 
 
 *See an able article on the "Physical Elements of Religion," by 
 Mr. L. Owen Pike, in " Anthropolo'g. Review," April, 1870, p. 63. 
 
 f" Religion, Moral, etc., der Darwin'schen Art-Lehre," 1869, s. 
 53. It is said (Dr. W. Lauder Lindsay, "Journal of Mental 
 Science," 1871, p. 43), that Bacon long ago, and the poet Burns, held 
 the same notion. 
 
 f " Prehistoric Times," 2d edit., p. 571. In this work (p. 571) 
 there will be found an excellent account of the many strange and 
 capricious customs of savages.
 
 MENTAL POWERS. 109 
 
 well observed, " it is not too much to say that the horrible 
 dread of unknown evil hangs like a thick cloud over savage 
 life and embitters every pleasure." These miserable and 
 indirect consequences of our highest faculties may be com- 
 pared with the incidental and occasional mistakes of the 
 instincts of the lower animals.
 
 1 J TEE DESCENT OF MAN. 
 
 CHAPTER IV. 
 
 COMPARISON" OF THE MENTAL POWERS OF MAN AND THE 
 
 LOWER ANIMALS. Continued. 
 
 The moral sense Fundamental proposition The qualities of social 
 animals Origin of sociability Struggle between opposed in- 
 stincts Man a social animal The more enduring social instincts 
 conquer other less persistent instincts The social virtues alons re- 
 garded by savages The self-regarding virtues acquired at a 
 later stage of development The importance of the judgment of 
 the members of the same community on conduct Transmission 
 of moral tendencies Summary, 
 
 I FULLY subscribe to the judgment of those writers* who 
 maintain that of all the differences between man and the 
 lower animals, the moral sense or conscience is by far the 
 most important. This sense, as Mackintosh f remarks, 
 " has a rightful supremacy over every other principle of 
 human action;" it is summed up in that short but imperi- 
 ous word ought, so full of high significance. It is the most 
 noble of all the attributes of man, leading him without a 
 moment's hesitation to risk his life for that of a fellow- 
 creature; or after due deliberation, impelled simply by the 
 deep feeling of right or duty,, to sacrifice it in some great 
 cause. Immanuel Kant exclaims : '' Duty i "Wondrous 
 thought, that workest neither by fond insinuation, flattery, 
 nor by any threat, but merely by holding up thy naked law 
 in the soul, and so extorting for thyself always reverence, if 
 not always obedience; before whom all appetites are dumb, 
 however secretly they rebel; whence thy original?''' J 
 
 *See, for instance, on this subject, Quatrefages, "Unite" de 1'Es- 
 pece Humaine," 1861, p. 21, etc. 
 
 f " Dissertation on Ethical Philosophy," 1837, p. 281, etc. 
 
 1 " Metaphysics of Ethics." translated by J. W. Semple, 
 burgh, 1836, p 136
 
 MORAL SENSE. Ill 
 
 This great question has been discussed by many writers * 
 of consummate ability ; and my sole excuse for touching on 
 it, is the impossibility of here passing it over; and because, 
 as far as I know, no one has approached it exclusively from 
 the side of natural nistory. The investigation possesses, 
 also, some independent interest, as an attempt to see how 
 far the study of the lower animals throws light on one of 
 the highest psychical faculties of man. 
 
 The following proposition seems to me in a high degree 
 probable namely, that any animal v \atever, endowed with 
 well-marked social instincts, f the parental and filial affec- 
 tions being here included, would inevitably acquire a 
 moral sense or conscience, as soon as its intellectual powers 
 had become as well, or nearly as well developed, as in man. 
 For, firstly, the social instincts lead an animal to take 
 pleasure in the society of its fellows, to feel a certain 
 amount of sympathy with them, and to perform various 
 services for them. The services may be of a definite and 
 evidently instinctive nature ; or there may be only a wish 
 
 *Mr, Bain gives a list( ;i: Mental and Moral Science," 1868, pp. 543- 
 725) of twenty-six British authors who have written on this subject, 
 and whose names are familiar to every reader; to these, Mr. Bain's 
 own name, and those of Mr. Lecky, Mr. Shad worth Hodgson, Sir J. 
 Lubbock and others, might be added. 
 
 f Sir B. Brodie, after observing that man is a social animal (' Psy- 
 chological Enquiries," 1854, p. 192), asks the pregnant question, 
 "ought not Shis to settle the disputed question as to the existence of 
 a moral sense?" Similar ideas have probably occurred to many per- 
 sons, as they did long ago to Marcus Aurelius. Mr. J. S. Mill 
 speaks, in his celebrated work, " Utilitarianism," (1864, pp. 45, 46), 
 of the social feelings as a '' powerful natural sentiment," and as " the 
 natural basis of sentiment for utilitarian morality." Again he says, 
 " Like the other acquired capacities above referred to, the moral 
 faculty, if not a part of our nature, is a natural outgrowth from it; 
 capable, like them, in a certain small degree of springing up sponta- 
 neously." But in opposition to all this, he also remarks, " if, as is 
 my own belief, the moral feelings are not innate, but acquired, they 
 are not for that reason less natural." It is with hesitation that I 
 venture to differ at all from so profound a thinker^ but it can hardly 
 be disputed that the social feelings are instinctive or innate in the 
 lower animals; and why should they not be so in man? Mr. Bain 
 (see, for instance, "The Emotions and the Will/' 1865, p. 481) and 
 others believe that the moral sense is acquired by each individual 
 during his lifetime. On the general theory of evolution this is at 
 least extremely improbable. The ignoring of all transmitted mental 
 qualities will, as it seems to me, be hereafter judged as a *rost serious 
 blemish in the wo.'', of Mr. Mill.
 
 112 THE DESCENT OF MAN. 
 
 and readiness, as with most of the higher social animals, to 
 aid their fellows in certaia general ways. But these feel- 
 ings and services are by no means extended to all the indi- 
 viduals of the same species, only to those of the same asso- 
 ciation. Secondly, as soon as the mental faculties had 
 become highly developed, images of all past actions and 
 motives would be incessantly passing through the brain of 
 each individual; and that feeling of dissatisfaction, or even 
 misery, which invariably results, as we shall hereafter see, 
 from any unsatisfied instinct, would arise, as often as it 
 was perceived that the enduring and always present social 
 instinct had yielded to some other instinct, at the time 
 stronger, but neither enduring in its nature, nor leaving 
 behind it a very vivid impression. It is clear that many 
 instinctive desires, such as that of hunger, are in their 
 nature of short duration; and after being satisfied, are not 
 readily or vividly recalled. Tliirdly, after the power of 
 language had been acquired, and tb.3 wishes of the commu- 
 nity could be expressed, the common opinion how each 
 member ought to act for the public good, would naturally 
 become in a paramount degree the guide to action. But it 
 should be borne in mind that however great weight we may 
 attribute to public opinion, our regard for the approbation 
 and disapprobation of our fellows depends on sympathy, 
 which, as we shall see, forms an essential part of the social 
 instinct, and is indeed its foundation-stone. Lastly, habit 
 in the individual would ultimately play a very important 
 Dart in guiding the conduct of each member; for the social 
 instinct, together with sympathy, is, like any other instinct, 
 greatly strengthened by habit, and so consequently would 
 be obedience to the wishes and judgment of the community. 
 These several subordinate propositions must now be discussed, 
 and some of them at considerable length. 
 
 It may be well first to premise that I do not wish to 
 maintain that any strictly social animal, if its intellectual 
 faculties were to become as active and as highly developed 
 as in man, would acquire exactly the same moral sense as 
 ours. In the same manner as various animals have some 
 sense of beauty, though they admire widely different 
 objects, so they might have a sense of right and wrong, 
 though led by it to follow widely different lines of conduct. 
 If, for instance, to take an extreme case, men were rcareu 
 under precisely the same conditions as hive-bees, there can
 
 MORAL SENSE. 113 
 
 hardly be a doubt that our unmarried females would, like 
 the worker-bee?, think it a sacred duty to kill their 
 brothers, and mothers would strive to kill their fertile 
 daughters; and no one would thin* of interfering,* Nevear- 
 theless, the bee, or any other social animal, would gain in 
 our supposed case, as it appears to me, some feeling of 
 right or wrong, or a conscience, For each individual 
 would have an inward sense of possessing certain stronger 
 or more enduring instincts, and others less strong or 
 enduring; so that there would often be a struggle as to 
 which impulse should be followed; and satisfaction, dissat- 
 isfaction, or even misery would oe felt, as past impressions 
 -vere compared during their incessant passage through the 
 mind. In this case an inward monitor would tell the 
 animal that it would have been better to have followed the 
 one impulse rather chan the other. The one coarse ought 
 to have been followed, and the other ought no'c^ the one 
 would have been right and the other wrong; but to these 
 terms I shall recur. 
 
 Sociability, Animais of many kinds are social; we find 
 even distinct species living together , for example, some 
 American monkeys ; and united docks of rooks, jackdaws 
 and starlings. Man shows the same feeling in his strong 
 love for the dog, which the dog returns with interest. Every 
 one must have noticed how miserable horses, dogs, sheep, 
 etc., are when separated from their companion,, and what 
 
 * Mr. H. Sidgwick remarks, in an able discussion on this subject 
 (the "Academy," June 15, 1872, p, 231), 'a. superior bee, we may 
 feel sure, would aspire to a milder solution of the population ques- 
 tion." Judging, however, from the habits of many or most savages, 
 man solves the problem by female infanticide, polyandry and pro- 
 miscuous intercourse, therefore it may well be doubted whether it 
 wuld be by a milder method. Miss Cobbe, in commenting (" Darwin- 
 ism in Morals," 'Theological Review," April, 1872, pp. 188-191) on 
 the same illustration, says, the principles of social duty would be 
 thus reversed; and by this, I presume, she means that the fulfill 
 ment of a social duty would tend to the injury of .ndivmuais, but 
 ghe overlooks the fact, which she would doubtless idmii. thai, Sho 
 instincts of the bee have been acquired for tb.3 good 3? th ,- commu- 
 nity, She goes so far as to say that if the theory :>f dthics advocated 
 in this chapter were ever generally accepted, j. cannot bos oeiieve 
 that in the hour of their triumph would be sounded 'cho .snell ji ins 
 virtue of mankind.*' It is to be hoped ihat the belief ui die perma- 
 nence of virtue on this earth is not held by many persons on so weak 
 a tenure.
 
 114 THE DESCENT OF MAN. 
 
 strong mutual affection the two former kinds, at least, 
 show on their reunion. It % is curious to speculate on the 
 feelings of a dog, who will' rest peacefully for hours in a 
 room with his master or any of the family, without the least 
 notice being taken of him; but if left for a short time by 
 himself, barks or howls dismally. We will confine our at- 
 tention to the higher social animals, and pass over insects, 
 although some of these are social, and aid one another in 
 many important ways. The most common mutual service 
 in the higher animals is to warn one another of danger by 
 means of the united senses of all. Every sportsman knows, 
 as Dr. Jaeger remarks,* how difficult it is to approach 
 animals in a herd or troop. Wild horses and cattle do not, 
 I believe, make any danger-signal ; but the attitude of any 
 one of them who first discovers an enemy, warns the others. 
 Rabbits stamp loudly on the ground with their hind feet as 
 a signal ; sheep and chamois do the same with their fore 
 feet, uttering likewise a whistle. Many birds and some 
 mammals, post sentinels, which in the case of seals are saidf 
 
 fenerally to be the females. The leader of a troop of mon- 
 eys acts as the sentinel, and utters cries expressive both of 
 danger and of safety. Social animals perform many little 
 services for each other; horses nibble, and cows lick each 
 other, on any spot which itches; monkeys search each other 
 for external parasites; and Brehm states that after a troop 
 of the Cercopithecus griseo-viridis has rushed through a 
 thorny brake, each monkey stretches itself on a branch, 
 and another monkey sitting by, " conscientiously " examines 
 its fur, and extracts every thorn or burr. 
 
 Animals also render more important services to one 
 another; thus wolves and some other beasts of prey hunt in 
 packs, and aid one another in attacking their victims. Peli- 
 cans fish in concert. The Hamadryas baboons turn over 
 stones to find insects, etc. ; and when they come to a large 
 one, as many as can stand round, turn it over together and 
 
 *"Die Darwin'sche Theorle," s. 101. 
 
 fMr. R. Brown in "Proc. Zoolog. Soc.," 1868, p. 409. 
 
 f Brehm, " Thierleben," B. i, 1864, s. 52, 79. For the case of the 
 monkeys extracting thorns from each other, see s. 54. With respect 
 to the Hamadryas turning over stones, the fact is given (s. 76) on the 
 evidence of Alvarez, whose observations Brehm thinks quite trust- 
 worthy. For the cases of the old male baboons attacking the dogs, 
 see a 79; and with respect to the eagle B. 56.
 
 MORAL SENSE. 115 
 
 share the hooty. Social animals mutually defend each other. 
 Bull bisons in North America, when there is danger, drive 
 the cows and calves into the middle of the herd, while they 
 defend the outside. I shall also in a future chapter give an 
 account of two young wild bulls at Ohillingliam attacking 
 an old one in concert, and of two stallions together trying 
 to drive away a third stallion from a troop of mares. In 
 Abyssinia, Brehm encountered a great troop of baboons 
 who were crossing a valley ; some had already ascended 
 che opposite mountain, and some were still in the valley; 
 the latter were attacked by the dogs, but the old males im- 
 mediately hurried down from the rocks, and with mouths 
 widely opened, roared so fearfully that the dogs quickly 
 drew back. They were again encouraged to the attack; but 
 by this time all the baboons had reascended the heights, 
 excepting a young one about six months old, who, loudly 
 calling for aid, climbed on a block of rock and was sur- 
 rounded. Now one of the largest males, a true hero, came 
 down again from the mountain, slowly went to the young 
 one, coaxed him, and triumphantly led him away the dogs 
 being too much astonished to make an attack. I cannot 
 resist giving another scene which was witnessed by this 
 same naturalist ; an eagle seized a young Cercopithecus, 
 which, by clinging to a branch, was not at once carried off; 
 it cried loudly for assistance, upon which the other mem- 
 bers of the troop, with much uproar, rushed to the rescue, 
 surrounded the eagle, and pulled out so many feathers that 
 he no longer thought of his prey, but only how to escape. 
 This eagle, as Brehm remarks, assuredly would never again 
 attack a single monkey of a troop.* 
 
 It is certain that associated animals have a feeling of love 
 for each other which is not felt by non-social adult animals. 
 How far in most cases they actually sympathize in the pains 
 and pleasures of others is more doubtful, especially with 
 respect to pleasures. Mr. Buxton, however, who had excel- 
 lent means of observation,! states that his macaws, which 
 
 * Mr. Belt gives the case of a spider-monkey (Ateles) in Nicaragua, 
 which was heard screaming for nearly two hours in the forest, and 
 Tvas found with an eagle perched close by it. The bird apparently 
 feared to attack as long as it remained face to face; and Mr. Belt be- 
 lieves, from what he has seen of the habits of these monkeys, that 
 they protect themselves from eagles by keeping two or three 
 together. " The Naturalist in Nicaragua," 1874, p. 118. 
 
 f" Annals of Mag. of Nat. Hist.." Nov., 1868, p. 382.
 
 116 THE DESCENT OF MAN. 
 
 lived free in Norfolk, took "an extravagant interest" in a 
 pair with a nest; and whenever the female left it she was* 
 surrounded by a troop " screaming horrible acclamations in 
 her honor." It is often difficult to judge whether animals 
 have any feeling for the sufferings of others of their kind. 
 Who can say what cows feel when they surround and stare 
 intently on a dying or dead companion; apparently, how- 
 ever, as Houzeau remarks, they feel BO pity. That animals 
 sometimes are far from feeling any sympathy is too certain; 
 for they will expel a wounded animal from the herd, or 
 gore or worry it to death. This is almost the blackest fact 
 in natural history, unless, indeed, the explanation which 
 has been suggested is true, that their instinct or reason 
 leads them to expel an injured companion, lest beasts of 
 
 frey, including man,, should be tempted to follow the troop, 
 a this case their conduct is not much worse than that of 
 the North American Indians, who leave their feeble com- 
 rades to perish on the plains; or the Fijians, who, wlin 
 their parents get old, or fall ill, bury them alive.* 
 
 Many animals, however, certainly sympathize with each 
 other's distress or danger. This is the case even with birds. 
 Capt. Stansburyf found on a salt lake in Utah an old 
 and completely blind pelican, which was very fat, and 
 must have been well fed for a long time by his companions. 
 Mr. Blyth, as he informs me, saw Indian crows feeding two 
 or three of their companions which were blind; and I have 
 heard of an analogous case with the domestic cock. We 
 may, if we choose, call these actions instinctive; but such 
 cases are much too rare for the development of any special 
 instinct. J I have myself seen a dog, who never passed 
 a cat who lay sick in a basket, and was a great friend of his, 
 without giving her a few licks with his tongue, the surest 
 sign of kind feeling in a dog. 
 
 It must be called sympathy that leads a courageous dog 
 to fly at any one who strikes his master, as he certainly will. 
 
 Sir J. Lubbook, "Prehistoric Times/' 2d edit., p, 446. 
 
 f As quoted by Mr. L. H. Morgan, " The American Beaver," 1868, 
 p. 272. Capt. Stansbury also gives an interesting account of the 
 manner in which a very young pelican, carried away by a strong 
 rtream, was guided and encouraged in its attemps to reach the shore 
 by half a dozen old birds. 
 
 JAs Mr. Bain states, "effective aid to a sufferer springs from 
 sympathy proper." " Mental and Moral Science," 1868, p, 245.
 
 MORAL SENSE. 117 
 
 I saw a person pretending to beat a lady, who had a very 
 timid little dog on her lap, and the trial had never been 
 made before; the little creature instantly jumped away, but 
 after the pretended beating was over, it was really pathetic 
 to see how perseveringly he tried to lick his mistress' face, 
 and comfort her. Brehm * states that when a baboon in 
 confinement was pursued to be punished, the others tried 
 to protect him. It must have been sympathy in the cases 
 above given which led the baboons and Cercopitheci to 
 defend their young comrades from the dogs and the eagle. 
 I will give only one other instance of sympathetic and 
 heroic conduct, in the case of a little American monkey. 
 Several years ago a keeper at the Zoological Gardens showed 
 me some deep and scarcely healed wounds on the nape 
 of his own neck, inflicted on him, while kneeling on the 
 floor, by a fierce baboon. The little American monkey, 
 who was a warm friend of this keeper, lived in the same 
 large compartment, and was dreadfully afraid of the great 
 baboon. Nevertheless, as soon as he saw his friend in 
 peril, he rushed to the rescue, and by screams and bites so 
 distracted the baboon that the man was able to escape, 
 after, as the surgeon thought, running great risk of his 
 life. 
 
 Besides love and sympathy, animals exhibit other quali- 
 ties connected with the social instincts, which in us would 
 be called moral; and I agree with Agassiz f that dogs 
 possess something very like a conscience. 
 
 Dogs possess some power of self-command, and this does 
 not appear to be wholly the result of fear. As Braubach J 
 remarks, they Avill refrain from stealing food in the absence 
 of their master. They have long been accepted as the very 
 type of fidelity and obedience. But the elephant is like- 
 wise very faithful to his driver or keeper, and probably con- 
 siders him as the leader of the herd. Dr. Hooker informs me 
 that an elephant, which he was riding in India, became so 
 deeply bogged that he remained stuck fast until the next 
 day, when he was extricated by men with ropes. Under 
 such circumstances elephants will seize with their trunk? 
 any object, dead or alive, to place under their knees, to 
 
 * " Thierleben," B. i, s. 85. 
 
 f " De 1'Espece et de la Classe," 1869, p. 97. 
 
 j "Die Darwin'sche Art-Lehre," 1869, s. 54.
 
 118 THE DESCENT OF MAN. 
 
 prevent their sinking deeper *. the mud; and the driver 
 was dreadfully afraid lest the animal should have seized 
 Dr. Hooker and crushed him to death. But the driver 
 himself, as Dr. Hooker was assiired, ran no risk. This for- 
 bearance, under an emergency so dreadful for a heavy 
 animal, is a wonderful proof of noble fidelity.* 
 
 All animals living in a body, which defend themselves or 
 attack their enemies in concert, must indeed be in some 
 degree faithful to one another ; and those that follow 
 a leader must be in some degree obedient. When the 
 baboons in Abyssiuiaf plunder a garden, they silently follow 
 their leader; and if an imprudent young animal makes a 
 a noise, he receives a slap from the others to teach him 
 silence and obedience. Mr. Galton, who has had excellent 
 opportunities for observing the half-wild cattle in S. Africa, 
 says,J that they cannot endure even a momentary separa- 
 tion from the herd. They are essentially slavish, and 
 accept the common determination, seeking no better lot 
 than to be led by any one ox who has enough self-reliance 
 to accept the position. The men who break in these ani- 
 mals for harness, watch assiduously for those who, by graz- 
 ing apart, show a self-reliant disposition, and these they 
 train as fore oxen. Mr. Galton adds that such animals are 
 rare and valuable; and if many were born they would soon 
 be eliminated, as lions are always on the lookout for the 
 individuals which wander from the herd. 
 
 With respect to the impulse which leads certain animals 
 to associate together, and to aid one another in many ways, 
 we may infer that in most cases they are impelled by the 
 same sense of satisfaction or pleasure which they experi- 
 ence in performing other instinctive actions ; or by the 
 same sense of dissatisfaction as when other instinctive 
 actions are checked. We see this in innumerable instances 
 and it is illustrated in a striking manner by the acquired 
 instincts of our domesticated animals; thus a young shep- 
 herd-dog delights in driving and running round a flock of 
 sheep, but not in worrying them ; a young fox-hound 
 delights in hunting a fox, while some other kinds of dogs, 
 
 * See also Hooker's " Himalayan Journals," vol. ii, 1854, p. 333. 
 fBrehm, "Thierleben," B. i, s. 76. 
 
 JSee Ms extremely interesting paper on " Gregariousness in Cat- 
 tle and in Man," "Macmillan's Mag.," Feb., 1871, p. 353.
 
 MORAL SENSE. 119 
 
 as I have witnessed, utterly disregard foxes. What a 
 strong feeling of inward satisfaction must impel a bird so 
 full of activity, to brood day after day over her eggs. 
 Migratory birds are quite miserable if stopped from migra- 
 ting; perhaps they enjoy starting on their long flight; but 
 it is hard to believe that the poor pinioned goose, described 
 by Audubon, which started on foot at the proper time for 
 its journey of probably more than a thousand miles, could 
 have felt any joy in doing so. Some instints are determined 
 solely by painful feelings, as by fear, which leads to self- 
 preservation, and is in some cases directed toward special 
 enemies. No one, I presume, can analyze the sensations 
 of pleasure or pain. In many instances, however, 
 it is probable that instincts are persistently followed 
 from the mere force of inheritance, without the stimulus 
 of either pleasure or pain. A young pointer, when it first 
 scents game, apparently cannot help pointing. A squirrel 
 in a cage who pats the nuts which it cannot eat, as. if to 
 bury them in the ground, can hardly be thought to act 
 thus, either from pleasure or pain. Hence the common 
 assumption that men must be impelled to every action by 
 experiencing some pleasure or pain may be erroneous. 
 Although a habit may be blindly and implicitly followed, 
 independently of any pleasure or pain felt at the moment, 
 yet if it be forcibly and abruptly checked, a vague sense of 
 dissatisfaction is generally experienced. 
 
 It has often been assumed that animals were in the first 
 place rendered social, and that they feel, as a consequence 
 uncomfortable when separated from each other, and com- 
 fortable while together; but it is a more probable view that 
 these sensations were first developed in order that those 
 animals which would profit by living in society should be 
 induced to live together, in the same manner as the sense 
 of hunger and the pleasure of eating were, no doubt, first 
 acquired in order to induce animals to eat. The feeling of 
 pleasure from society is probably an extension of the 
 parental or filial affections, since the social instinct seems 
 to be developed by the young remaining for a long time 
 with their parents; and this extension may be attributed in 
 part to habit, but chiefly to natural selection. With those 
 animals which were benefited by living in close association, 
 the individuals which took the greatest pleasure in society 
 would best escape various dangers, while those that cared
 
 120 THE DESCENT OF MAN. 
 
 least for their comrades, and lived solitary, would perish in 
 greater numbers. With respect to the origin of the parental 
 and filial affections, which' apparently lie at the base of the 
 social instincts, we know not the steps by which they have 
 been gained; but we may infer that it has been to a large 
 extent through natural selection. So it has almost cer- 
 tainly been with the unusual and opposite feeling of hatred 
 between the nearest relations, as with the worker-bees 
 which kill their brother drones, and with the queen bees 
 which kill their daughter queens; the desire to destroy 
 their nearest relations having been in this case of service to 
 the community. Parental affection, or some feeling which 
 replaces it, has been developed in certain animals extremely 
 low in the scale, for example, in star-fishes and spiders. 
 It is also occasionally present in a few members alone in a 
 whole group of animals, as in the genus Forficula, or 
 earwigs. 
 
 The all-important emotion of sympathy is distinct from 
 that of love. A mother may passionately love her sleep- 
 ing and passive infant, but she can hardly at such times 
 be said to feel sympathy for it. The love of a man for 
 his dog is distinct from sympathy, and so is that of a dog 
 for his master. Adam Smith formerly argued, as has 
 Mr. Bain recently, that the basis of sympathy lies in our 
 strong retentiveness of former states of pain or pleasure. 
 Hence, "the sight of another person enduring hunger, 
 cold, fatigue, revives in us some recollection of the 
 states, which are painful even in idea." AVe are thus 
 impelled to relieve the sufferings of another in order that 
 our own painful feelings may be at the same time relieved. 
 In like manner we are led to participate in the pleasures of 
 others.* But I cannot see how this view explains the fact 
 that sympathy is excited, in an immeasurably stronger 
 degree, by a beloved, than by an indifferent person. 
 
 * See the first and striking chapter 'in Adam Smith's " Theory of 
 Moral Sentiments." Also Mr. Bain's " Mental and Moral Science," 
 1868, pp. 244 and 275-282. Mr. Bain states, that "sympathy is, in- 
 directly, a source of pleasure to the sympathizer;" and he accounts 
 for this through reciprocity. He remarks that " the person bene- 
 fited, or others in his stead, may make up, by sympathy and good 
 offices returned, for all the sacrifice." But if, as appears to be the 
 case, sympathy is strictly an instinct, its exercise would give direct 
 pleasure, in the same manner as the exercise, as before remarked, of 
 almost every other instinct.
 
 MORAL SENSE, 121 
 
 The mere sight of suffering, independently of love, would 
 suffice to call up in us vivid recollections and associations. 
 The explanation may lie in the fact that, with all animals, 
 sympathy is directed solely toward the members of the same 
 community, and therefore toward known and more or less 
 beloved members, but not to all the individuals of the same 
 species. This fact is not more surprising than that the 
 fears of many animals should be directed against special 
 enemies. Species which are not social, such as lions and 
 tigers, no doubt feel sympathy for the suffering of their own 
 young, but not for that of any other animal. With man- 
 kind selfishness, experience, and imitation, probably add, 
 as Mr. Bain has shown, to the power of sympathy; for we 
 are led by the hope of receiving good in return to perform 
 acts of sympathetic kindness to others; and sympathy is 
 much strengthened by habit. In however complex a 
 manner this feeling may have originated, as it is one of high 
 importance to all those animals which aid and defend one 
 another, it will have been increased through natural selec- 
 tion; for those communities, which included the greatest 
 number of the most sympathetic members, would flourish 
 best and rear the greatest number of offspring. 
 
 It is, however, impossible to decide in many cases whether 
 certain social instincts have been "acquired through natural 
 selection, or are the indirect result of other instincts and 
 faculties, such as sympathy, reason, experience, and a ten- 
 dency to imitation; or again, whether they are simply -the 
 result of long-continued habit. So remarkable an instinct 
 as the placing sentinels to warn the community of danger 
 can hardly have been the indirect result of any of these 
 faculties; it must, therefore, have been directly acquired. 
 On the other hand, the habit followed by the males of some 
 social animals of defending the community, and of attack- 
 ing their enemies or their prey in concert, may perhaps 
 have originated from mutual sympathy; but courage, and 
 in most cases strength, must have been previously acquired, 
 probably through natural selection. 
 
 Of the various instincts and habits, some are much 
 stronger than others; that is, some either give more pleas- 
 ure in their performance, and more distress in their pre- 
 vention, than others; or, which is probably quite as impor- 
 tant, they are, through inheritance, more persistently 
 f ollowed, without exciting any special feeling of pleasure
 
 122 THE DESCENT OF MAN. 
 
 or pain. "We are ourselves conscious that some habits are 
 much more difficult to cure or change than others. Hence 
 a struggle may often be observed in animals between dif- 
 ferent instincts, or between an instinct and some habitual 
 disposition; as when a dog rushes after a hare, is rebuked, 
 pauses, hesitates, pursues again, or returns ashamed to his 
 master; or as between the love of a female dog for her 
 young puppies and for her master for she may be seen to 
 slink away to them as if half-ashamed of not accompanying 
 her master. But the most curious instance known to me of 
 one instinct getting the better of another, is the migratory 
 instinct conquering the maternal instinct. The former is 
 wonderfully strong; a confined bird will at the proper 
 season beat her breast against the wires of her cage until 
 it is bare and bloody. It causes young salmon to leap out 
 of the fresh water, in which they could continue to exist, 
 and thus unintentionally to commit suicide. Every one 
 knows how strong the maternal instinct is, leading even 
 timid birds to face great danger, though with hesitation, 
 and in opposition to the instinct of self-preservation. 
 Nevertheless, the migratory instinct is so powerful that 
 late in the autumn swallows, house-martins, and swifts fre- 
 quently desert their tender young, leaving them to perish 
 miserably in their nests.* 
 
 "We can perceive that an instinctive impulse, if it be in 
 any way more beneficial to a species than some other or 
 opposed instinct, would be rendered the more potent of the 
 two through natural selection; for the individuals which 
 had it most strongly developed would survive in larger num- 
 bers. Whether this is the case with the migratory in com- 
 parison with the maternal instinct, may be doubted. The 
 
 * This fact, the Rev. L. Jenyns states (see his edition of " White's 
 Nat. Hist, of Selborne," 1853, p. 204) was first recorded by the illus- 
 trious Jenner, in " Phil. Transact.," 1824, and has since been confirmed 
 by several observers, especially by Mr. Blackwall. This latter care- 
 ful observer examined, late in the autumn, during two years, thirty- 
 six nests; he found that twelve contained young dead birds, five con- 
 tained eggs on the point of being hatched, and three, eggs not nearly 
 hatched. Many birds, not yet old enough for a prolonged flight, are 
 likewise deserted and left behind. See Blackwall, " Researches in 
 Zoology," 1834, pp. 108, 118. For some additional evidence, although 
 this is" not wanted, see Leroy, " Lettres Phil.," 1802, p. 217. For 
 swifts, Gould's "Introduction to the Birds of Great Britain," 1823, 
 p. 5. Similar cases have been observed in Canada by Mr. Adams; 
 "Pop. Science Review," July, 1873, p. 283.
 
 MORAL SENSE. 123 
 
 great persistence or steady action of the former at certain 
 seasons of the year during the whole day, may give it for a 
 time paramount force. 
 
 Man a Social Animal. Every one will admit that man is 
 a social being. We see this in his dislike of solitude, and 
 in his wish for society beyond that of his own family. 
 Solitary confinement is one of the severest punishments 
 which can be inflicted. Some authors suppose that man 
 prime vally lived in single families; but at the present day, 
 though single families, or only two or three together, roam 
 the solitudes of some savage lands, they always, as far as I 
 can discover, hold friendly relations with other families 
 inhabiting the same district. Such families occasionally 
 meet in council, and unite for their common defense. It 
 is no argument against savage man being a social animal, 
 that the tribes inhabiting adjacent districts are almost 
 always at war with each other; for the social instincts never 
 extend to all the individuals o the same species. Judging 
 from the analogy of the majority of the Quadrumana, it is 
 probable that the early ape-like progenitors of man were 
 likewise social ; but this is not of much importance for us. 
 Although man, as he now exists, has few special instincts, 
 having lost any which his early progenitors may have 
 possessed, this is no reason why he should not have retained 
 from an extremely remote period some degree of instinctive 
 love and sympathy for his fellows. We are indeed all con- 
 scious that we do possess such sympathetic feelings;* but 
 pur consciousness does not tell us whether they are instinct- 
 ive, having originated long ago in the same manner 
 as with the lower animals, or whether they have been 
 acquired by each of us during our early years. As man is 
 a social animal, it is almost certain that he would inherit a 
 tendency to be faithful to his comrades and obedient to 
 the leader of his tribe; for these qualities are common to 
 most social animals. He would consequently possess some 
 capacity for self-command. He would from an inherited 
 
 *Hume remarks ('An Enquiry Concerning the Principles of 
 Morals," edit, of 1751, p. 132), "There seems a necessity for con- 
 fessing that the happiness and misery of others are not spectacles 
 altogether indifferent to us, but that the view of the former . . . 
 communicates a secret joy; the appearance of the latter . . 
 throws a melancholy damp over the imagination."
 
 124 THE DESCENT OF MAN. 
 
 tendency be willing to defend, in concert with others, his 
 fellow-men; and would b6' ready to aid them in any way, 
 which did not too greatly interfere with his own welfare or 
 his own strong desires. 
 
 The social animals which stand at the bottom of the scale 
 are guided almost exclusively, and those which stand higher 
 in the scale are largely guided, by special iastincts in the 
 aid which they give to the members of the same commu- 
 nity; but they are likewise in part impelled by mutual love 
 and sympathy, assisted apparently by some amount of 
 reason. Although man, as just remarked, has no special 
 instincts to tell him how to aid his fellow-men, he still has 
 the impulse, and with his improved intellectual faculties 
 would naturally be much guided in this respect by reason 
 and experience. Instinctive sympathy would also cause 
 him to value highly the approbation of his fellows; for, as 
 Mr. Bain has clearly shown,* the love of praise and the 
 strong feeling of glory, and the still stronger horror of 
 scorn and infamy, " are due to the workings of sympathy." 
 Consequently man would be influenced in the highest 
 degree by the wishes, approbation, and blame of his fellow- 
 men, as expressed by their gestures and language. Thus 
 the social instincts, which must have been acquired by man 
 in a very rude state, and probably even by his early ape-like 
 progenitors, still give the impulse to some of his best 
 actions; but his actions are in a higher degree determined 
 by the expressed wishes and judgment of his fellow-men, 
 : and unfortunately very often by his own strong selfish 
 desires. But as love, sympathy and self-command become 
 strengthened by habit, and as the power of reasoning 
 becomes clearer, so that man can value justly the judgments 
 of his fellows, he will feel himself impelled, apart from 
 any transitory pleasure or pain, to certain lines of conduct. 
 He might then declare not that any barbarian or unculti- 
 vated man could thus think I am the supreme judge of 
 my own conduct, and in the words of Kant, I will not in 
 my own person violate the dignity of humanity. 
 
 Tlie More Enduring Social Instincts Conquer the Less Per- 
 sistent Instincts. We have not, however, as yet considered 
 the main point, on which, from our present point of view. 
 
 " Mental and Moral Science," 1868, p. 254.
 
 MORAL SENSE. 125 
 
 the whole question of the moral sense turns. Why should 
 a man feel that he ought to obey one instinctive desire 
 rather than another? Why is he bitterly regretful, if he 
 has yielded to a strong sense of self-preservation, and has 
 not risked his life to save that of a fellow-creature? or why 
 does he regret having stolen food from hunger? 
 
 It is evident, in the first place, that with mankind the 
 instinctive impulses have different degrees of strength; a 
 savage will risk his own life to save that of a member of 
 the same community, but will be wholly indifferent about 
 a stranger ; a young and timid mother urged by the 
 maternal instinct will, without a moment's hesitation, 
 run the greatest danger for her own infant, but not for 
 a mere fellow-creature. Nevertheless many a civilized man, 
 or even boy, who never before risked his life for another, 
 but full of courage and sympathy, has disregarded the 
 instinct of self-preservation, and plunged at once into a 
 torrent to save a drowning man, though a stranger. In 
 this case man is impelled by the same instinctive motive 
 which made the heroic little American monkey, formerly 
 described, save his keeper, by attacking the great and 
 dreaded baboon. Such actions as the above appear to be 
 the simple result of the greater strength of the social or 
 maternal instincts than that of any other instinct or motive; 
 for they are performed too instantaneously for reflection, 
 or for pleasure or pain to be felt at the time; though, if 
 prevented by any cause, distress or even misery might be 
 felt. In a timid man, on the other hand, the instinct of 
 self-preservation might be so strong, that he would be 
 unable to force himself to run any such risk, perhaps not 
 even for his own child. 
 
 I am aware that some persons maintain that actions per- 
 formed impulsively, as in the above cases, do not come 
 under the dominion of the moral sense, and cannot be 
 called moral. They confine this term to actions done 
 deliberately, after a victory over opposing desires, or when 
 prompted by some exalted motive. But it appears scarcely 
 possible to draw any clear line of distinction of this kind c * 
 
 * I refer here to the distinction between what has been called 
 mutt rial and formal morality. I am glad to find that Prof. Huxley 
 ("Critiques and Addresses," 1873, p. 287) takes the same view on 
 this subject as I do. Mr. Leslie Stephen remarks (" Essays on Free- 
 thinking and Plain Speaking," 1873, p. 83), "the metaphysical dis- 
 tinction, between material and formal morality is as irrevelant as 
 other such distinctions."
 
 126 THE DESCENT OF MAN. 
 
 As far as exalted motives are concerned, many instances 
 have been recorded of savages, destitute of any feeling of 
 general benevolence toward mankind, and not guided by 
 any religious motive, who have deliberately sacrificed their 
 lives as prisoners,* rather than betray their comrades; and 
 surely their conduct ought to be considered as moral. As 
 far as deliberation, and the victory over opposing motives 
 are concerned, animals may be seen doubting between 
 opposed instincts, in rescuing their offspring or comrades 
 from danger; yet their actions, though done for the good 
 of others, are not called moral. Moreover, anything per- 
 formed very often by us, will at last be done without 
 deliberation or hesitation, and can then hardly be distin- 
 guished from an instinct; yet surely no one will pretend 
 that such an action ceases to be moral. On the contrary, 
 we all feel that an act cannot be considered as perfect, or 
 as performed in the most noble manner, unless, it be done 
 impulsively, without deliberation or effort, in the same 
 manner as by a man in whom the requisite qualities are 
 innate. He who is forced to overcome his fear or want of 
 sympathy before he acts, deserves, however, in one way 
 higher credit than the man whose innate disposition leads 
 him to a good act without effort. As we cannot distinguish 
 between motives, we rank all actions of a certain class as 
 moral, if performed by a moral being. A moral being is 
 one who is capable of comparing his past and future actions 
 or motives, and of approving or disapproving of them. We 
 have no reason to suppose that any of the lower animals 
 have this capacity; therefore, when a Newfoundland dog 
 drags a child out of the water, or a monkey faces danger to 
 rescue its comrade, or takes charge of an orphan monkey, 
 we do not call its conduct moral. But in the case of man, 
 who alone can with certainty be ranked as a moral being, 
 actions of a certain class are called moral, whether per- 
 formed deliberately, after a struggle with opposing motives, 
 or impulsively through instinct, or from the effects of 
 slowly gained habit. 
 
 But to return to our more immediate subject. Although 
 some instincts are more powerful than others, and thus lead 
 to corresponding actions, yet it is untenable, that in man 
 
 * I have given one such case, namely, of three Patagonian Indiana 
 who preferred being shot, one after the other, to betraying the plans 
 of their companions in war (" Journal of Researches," 1845, p. 103).
 
 MORAL SENSE. 127 
 
 the social instincts (including the love of praise and fear of 
 blame) possess greater strength, or have, through long 
 habit, acquired greater strength than the instincts of self- 
 preservation, hunger, lust, vengeance, etc. Why then does 
 man regret, even though trying to banish such regret, that 
 he has followed the one natural impulse rather than the 
 other; and why does he further feel that he ought to regret 
 his conduct? Man in this respect differs profoundly from 
 the lower animals. Nevertheless we can, I think, see with 
 some degree of clearness the reason of this difference. 
 
 Man, from the activity of his mental faculties, cannot 
 avoid reflection; past impressions and images are incessantly 
 and clearly passing through his mind. Now with those 
 animals which live permanently in a body, the social 
 instincts are ever present and persistent. Such animals are 
 always ready to utter the danger-signal, to defend the com- 
 munity, and to give aid to their fellows in accordance with 
 their habits; they feel at all times, without the stimulus of 
 any special passion or desire, some degree of love and sym- 
 pathy for them; they are unhappy if long separated from 
 them, and always happy to be again in their company. So 
 it is with ourselves. Even when we are quite alone, how 
 often do we think with pleasure or pain of what others 
 think of us of their imagined approbation or disapproba- 
 tion; and this all follows from sympathy, a fundamental 
 element of the social instinctSo A man who possessed no 
 trace of such instincts would be an unnatural monster. On 
 the other hand, the desire to satisfy hunger, or any passion 
 such as vengeance, is in its nature temporary, and can for a 
 time be fully satisfied. Nor is it easy, perhaps hardly pos- 
 sible, to call up with complete vividness the feeling, for 
 instance, of hunger; nor indeed, as has often been remarked, 
 of any suffering. The instinct of self-preservation is not 
 felt except in the presence of danger, and many a coward 
 has thought himself brave until he has met his enemy face 
 to face. The wish for another man^s property is perhaps 
 as persistent a desire as any that can be named: but even 
 in this case the satisfaction of actual possession is generally 
 a weaker feeling than the desire; many a thief, if not an 
 habitual one, after success has wondered why he stole some 
 article. * 
 
 * Enmity or hatred seems also to be a highly persistent, feeling, 
 perhaps more so than aoy ether that can be named. Envy is defined
 
 128 THE DESCENT OF MAN. 
 
 A man cannot prevent past impressions often repassing 
 through his mind; he wiU thus be driven to make a com- 
 parison between the impressions of past hunger, vengeance 
 satisfied, or danger shunned at other men's cost, with the 
 almost ever-present instinct of sympathy, and with his 
 early knowledge of what others consider as praiseworthy or 
 blameable. This knowledge cannot be banished from his 
 mind, and from instinctive sympathy is esteemed of great 
 moment. He will then feel as if he had been balked in 
 following a present instinct or habit, and this with all 
 animals causes dissatisfaction, or even misery. 
 
 The above case of the swallow affords an illustration, 
 though of a reversed nature, of a temporary though for the 
 time strongly persistent instinct conquering another in- 
 stinct, which is usually dominant over all others. At the 
 proper season these birds seem all day long to be impressed 
 with the desire to migrate ; their habits change ; they 
 become restless, are noisy and congregate in flocks. While 
 the mother-bird is feeding, or brooding over her nestlings, 
 the maternal instinct is probably stronger than the migra- 
 tory; but the instinct which is the more persistent gains 
 the victory, and at last, at a moment when her young ones 
 are not in sight, she takes flight and deserts them. When 
 arrived at the end of her long journey, and the migratory 
 instinct has ceased to act, what an agony of remorse the 
 bird would feel if, from being endowed with great mental 
 
 as hatred of another for some excellence or success; and Bacon in- 
 sists (Essay ix), "Of all other affections envy is the most importune 
 and continual." Dogs are very apt to hate both strange men and 
 strange dogs, especially if they live near at hand, but do not belong 
 to the same family, tribe, or clan; this feeling would thus seem to be 
 innate, and is certainly a most persistent one. It seems to be the 
 complement and converse of the true social instinct. From what we 
 hear of savages, it would appear that something of the same kind 
 holds good with them. If this be so, it would be a small step in any 
 one to transfer such feelings to any member of the same tribe if he 
 had done him an injury and had become his enemy. Nor is it 
 probable that the primitive conscience would reproach a man for in- 
 juring his enemy; rather it would reproach him, if lie had not 
 revenged himself. To do good in return for evil, to love your 
 enemy, is a height of morality to which it may be doubted whether 
 the soc'al instincts would, by themselves, have ever led us. It is 
 necessary that these instincts, together with sympathy, should have 
 been highly cultivated and extended by the aid ot reason, instruc- 
 tion, and the love or fear of <!o<l, before any such golden rule would 
 ever be thought, of and ol-cyi-d.
 
 MORAL SENSE. 129 
 
 activity, she could not prevent the image constantly passing 
 through her mind of her young ones perishing in the bleak 
 north from cold and hunger. 
 
 At the moment of action man will no doubt be apt to 
 follow the stronger impulse; and though this may occa- 
 sionally prompt him to the noblest deeds, it will more com- 
 monly lead him to gratify his own desires at the expense of 
 other men. But after their gratification, when past and 
 weaker impressions are judged by the ever-enduring social 
 instinct, and by his deep regard for the good opinion of 
 his fellows, retribution will surely come. He will then 
 feel remorse, repentance, regret or shame; this latter feel- 
 ing, however, relates almost exclusively to the judgment of 
 others. He will consequently resolve more or less firmly 
 to act differently for the future; and this is conscience; for 
 conscience looks backward and serves as a guide for the 
 future. 
 
 The nature and strength of the feelings which we call 
 regret, shame, repentance or remorse, depend apparently 
 not only on the strength of the violated instinct, but partly 
 on the strength of the temptation, and often still more on 
 the judgment of our fellows. How far each man values 
 the appreciation of others depends on the strength of his 
 innate or acquired feeling of sympathy; and on his own 
 capacity for reasoning out the remote consequences of his 
 acts. Another element is most important, although not 
 necessary, the reverence or fear of the gods, or. spirits 
 believed in by each man; and this applies especially in 
 cases of remorse. Several critics have objected that 
 though some slight regret or repentance may be explained 
 by the view advocated in this chapter, it is impossible thus 
 to account for the soul-shaking feeling of remorse. But I 
 can see little force in this objection. My critics do not 
 define what they mean by remorse, and I can find no defi- 
 nition implying more than an overwhelming sense of 
 repentance. Remorse seems to bear the same relation to 
 repentance as rage does to anger, or agony to pain. It is 
 far from strange that an instinct so strong and so gener- 
 ally admired, as maternal love, should, if disobeyed: lead to 
 the deepest misery, as soon as the impression of the past 
 cause of disobedience is weakened. Even when an action 
 is opposed to no special instinct, merely to know that onr 
 friends and equals despise us for it, is enough to cause great
 
 130 13E DESCENT OF MAN. 
 
 misery. Who can doubt that the refusal to fight a duel 
 through fear has causedv many men an agony of shame? 
 Many a Hindoo, it is said, has been stirred to the bottom 
 of his soul by having partaken of unclean food. Here is 
 another case of what must, I think, be called remorse. 
 Dr. Landor acted as a magistrate in West Australia, and 
 relates,* that a native on his farm, after losing one of his 
 wives from disease, came and said that " he was going to 
 a distant tribe to spear a woman, to satisfy his sense of, 
 duty to his wife. I told him that if he did so I would 
 send him to prison for life. He remained about the farm 
 for some months, but got exceedingly thin, and complained 
 that he could not rest or eat, that his wife's spirit was 
 haunting him, because he had not taken a life for hers. I 
 was inexorable, and assured him that nothing should save 
 him if he did/' Nevertheless the man disappeared for 
 more than a year, and then returned in high condition ; 
 and his other wife told Dr. Landor that her husband had 
 taken the life of a woman belonging to a distant tribe; but 
 it was impossible to obtain legal evidence of the act. The 
 breach of a rule held sacred by the tribe will thus, as it 
 seems, give rise to the deepest feelings and this quite 
 apart from the social instincts, excepting in so far as the 
 rule is grounded on the judgment of the community. 
 How so many strange superstitions have arisen throughout 
 the world we know not; nor can we tell how some real and 
 great erimes, such as incest, have come to be held in an 
 abhorrence (which is not however quite universal) by the 
 lowest savages. It is even doubtful whether in some tribes 
 incest would be looked on with greater horror than would 
 the marriage of a man with a woman bearing the same 
 name, though not a relation. " To violate this law is a 
 crime which the Australians hold in the greatest abhor- 
 rence, in this agreeing exactly with certain tribes of North 
 America. When the question is put in either district, is 
 it worse to kill a girl of a foreign tribe, or to marry a girl 
 of one's own. ;m answer just opposite to ours would be given 
 without hesitation.''! \\'v. may, therefore, reject the 
 belief, late , insisted on by some writers, that the abhor- 
 
 "Insamiy ID delation to Law," Ontario, United States, 1871, 
 p. 1. 
 t E. B. Tylor in "Contemporary Review," April, 1873, p. 707.
 
 MORAL SENSE. 131 
 
 rence of incest is due to our possessing a special God- 
 implanted conscience. On the whole it is intelligible, that 
 a man urged by so powerful a sentiment as remorse though 
 arising as above explained, should be led to act in a manner, 
 which he has been taught to believe serves as an expiation, 
 such as delivering himself up to justice. 
 
 Man prompted by his conscience, will through long habit 
 acquire such perfect self-command, that his desires and 
 passions will at last yield instantly and without a struggle 
 to his social sympathies and instincts, including his feeling 
 for the judgment of his fellows. The still hungry, or the 
 still revengeful, man will not think of stealing food, or ol 
 wreaking his vengeance. It is possible, or as we shall here- 
 after see, even probable, that the habit of self-command 
 may, like other habits, be inherited. Thus at last man 
 comes to feel, through acquired and perhaps inherited 
 habit, that it is best for him to obey his more persistent 
 impulses. The imperious word ought seems merely to 
 imply the consciousness of the existence of a rule of con- 
 duct, however it may have originated. Formerly it must 
 have been often vehemently urged that an insulted 
 gentleman ought to fight a duel. We even say that a 
 pointer ought to point, and a retriever to retrieve game. 
 If they fail to do so, they fail in their duty and act 
 wrongly. 
 
 If any desire or instinct leading to an action opposed to 
 the good of others still appears, when recalled to mind, as 
 strong as, or stronger than, the social instinct, a man will 
 feel no keen regret at having followed it; but he will be 
 conscious that if his conduct were known to his fellows, it 
 would meet with their disapprobation; and few are so desti- 
 tute of sympathy as not to feel discomfort when this is 
 realized. If he has no such sympathy, and if his desires 
 leading to bad actions are at the time strong, and when 
 recalled are not overmastered by the persistent social 
 instincts, and the judgment of others, then he is essen- 
 tially a bad man; * and the sole restraining motive left 
 is the fear of punishment, and the conviction that in the 
 long run it would be best for his own selfish interests to 
 regard the good of others rather than his own. 
 
 *Dr Prosper Despine in his " Psychologie Naturelle," 1868 (torn. 
 1, p. 243; torn, ii, p. 169), gives many curious cases of the worst 
 criminals, who apparently have been entirely destitute of conscience.
 
 132 THE DESCENT OF MAN. 
 
 It is obvious that every one may with an easy conscience 
 tratify his own desires,, ii they do not interfere with his 
 i>cial instincts, that is with the good of others; but in 
 order to be quite free from self-reproach, or at least of 
 anxiety, it is almost necessary for him to avoid the disap- 
 probation, whether reasonable or not, of his fellow-men. 
 Nor must he break through the fixed habits of his life, 
 especially if these are supported by reason; for if he does, 
 he will assuredly feel dissatisfaction. He must likewise 
 avoid the reprobation of the one God or gods in whom, 
 according to his knowledge or superstition, he may believe; 
 but in this case the additional fear of divine punishment 
 often supervenes. 
 
 The Strictly Social Virtues at First Alone Regarded. 
 The above view of the origin and nature of the moral sense, 
 which tells us what we ought to do, and of the conscience 
 which reproves us if we disobey it, accords well with what 
 we see of the early and undeveloped condition of this faculty 
 in mankind. The virtues which must be practiced, at least 
 generally, by rude men, so that they may associate in a body, 
 are those which aie still recognized as the most important. 
 But they are practiced almost exclusively in relation to the 
 men of the same tribe; and their opposites are not regarded 
 as crimes in relation to the men of other tribes. No tribe 
 could hold together if murder, robbery, treachery, etc., 
 were common, consequently such crimes within the limits 
 of the same tribe " are branded with everlasting infamy;"* 
 but excite no such sentiment beyond these limits. A North 
 American Indian is well pleased with himself, and is hon- 
 ored by others, when he scalps a man of another tribe; and 
 a Dyak cuts off the head of an unoffending person, and 
 dries it as a trophy. The murder of infants has prevailed 
 on the largest scale throughout the world, f and has met 
 with no reproach; but infanticide, especially of females, 
 has been thought to be good for the tribe, or at least not 
 injurious. Suicide during former times was not generally 
 
 *See an able article in the " North British Review," 1867, p. 395 
 See also Mr. W. Bagehot's articles on the " Importance of Obedience" 
 end "Coherence to Primitive Man," in the " Fortnightly Review," 
 1867, p. 529, and 1868, p. 457, etc. 
 
 \ The fullest account which I have met with is by Dr. Gerland, in 
 hi* " Uebor <la- Aussterben der Xatnrvolker," 1868; but I shall have 
 to recur to the subject of infanticide ifl ttt'uture chapter.
 
 MORAL SENSE. 133 
 
 considered as a crime,* but rather, from the courage dis- 
 played, as an honorable act; and it is still practiced by some 
 semi-civilized and savage nations without reproach, for it 
 does not obviously concern others of the tribe. It has 
 been recorded that an Indian Thug conscientiously regret- 
 ted that he had not robbed and strangled as many trav- 
 elers as did his father before him. In a rude state of 
 civilization the robbery of strangers is, indeed, generally 
 considered as honorable. 
 
 Slavery, although in some ways beneficial during ancient 
 times, f is a great crime; yet it was not so regarded until 
 quite recently, even by the most civilized nations. And 
 this was especially the case, because the slaves belonged in 
 general to a race different from that of their masters. As 
 barbarians do not regard the opinions of their women, 
 wives are commonly treated like slaves. Most savages are 
 utterly indifferent to the sufferings of strangers, or even 
 delight in witnessing them. It well known that the women 
 and children of the North American Indians aided in tor- 
 turing their enemies. Some savages take a horrid pleas- 
 ure in cruelty to animals, J and humanity is an unknown 
 virtue. Nevertheless, besides the family affections, kind- 
 ness is common, especially during sickness, between the 
 members of the same tribe, and is sometimes extended 
 beyond these limits. Mungo Park's touching account of 
 the kindness of the negro women of the interior to him 
 is well known. Many instances could be given of the noble 
 fidelity of savages toward each other, but not to strangers; 
 common experience justifies the maxim of the Spainard. 
 "Never, never trust an Indian." There cannot be fidelity 
 without truth ; and this fundamental virtue is not rare 
 between the members of the same tribe; thus Mungo Park 
 
 *See the very interesting discussion on Suicide in Lecky's "Hist 
 ory of European Morals," vol. i, 1869, p. 228. With respect to sav- 
 ages, Mr. Winwood Reade informs me that the negroes of West 
 Africa often commit suicide. It is well known how common it was 
 among the miserable Aborigines of South America after the Spanish 
 conquest. For New Zealand, see the voyage of the "Novara," and 
 for the Aleutian Islands, Miiller, as quoted by Houzeau, " Les 
 Facultes Mentales," etc., torn, ii, p. 136. 
 
 t See Mr. Bagehot, "Physics and Politics," 1872, p. 72. 
 
 JSee, for instance, Mr. Hamilton's account of the Kaffirs, "An- 
 thropological Review," 1870, p. 15.
 
 134 THE DESCENT OF MAN. 
 
 heard the negro women teaching their young children to 
 love the truth. This, again, is one of the virtues which 
 becomes so deeply rooted in the mind that it is sometimes 
 practiced by savages, even at a high cost, toward strangers; 
 but to lie to your enemy has rarely been thought a sin, as 
 the history of modern diplomacy too plainly shows. As 
 soon as a tribe has a recognized leader disobedience becomes 
 a crime, and even abject submission is looked at as a sacred 
 virtue. 
 
 As during rude times no man can be useful or faithful t<? 
 his tribe without courage, this quality has universally been 
 placed in the highest rank; and although in civilized coun- 
 tries a good yet timid man may be far more useful to the 
 community than a brave one, we cannot help instinctively 
 honoring the latter above a coward, however benevolent. 
 Prudence, on the other hand, which does not concern the 
 welfare of others, though a very useful virtue, has never 
 been highly esteemed. As no man can practice the virtues 
 necessary for the welfare of his tribe without self-sacrifice, 
 self-command, and the power of endurance, these qualities 
 have been at all times highly and most justly valued. The 
 American savage voluntarily submits to the most horrid 
 tortures without a groan, to prove and strengthen his forti- 
 tude and courage; and we cannot help admiring him, or 
 even an Indian Fakir, who, from a foolish religious motive, 
 swings suspended by a hook buried in his flesh. 
 
 The other so-called self-regarding virtues, which do not 
 obviously, though they may really, affect the welfare of the 
 tribe, have never been esteemed by savages, though now 
 highly appreciated by civilized nations. The greatest 
 intemperance is no reproach with savages. Utter licen- 
 tiousness and unnatural crimes prevail to an astounding 
 extent.* As soon, however, as marriage, whether polyga- 
 mous or monogamous, becomes common, jealousy will lead 
 to the inculcation of female virtue; and this being honored, 
 will tend to spread to the unmarried females. How slowly 
 it spreads to the male sex, we see at the present day. 
 Chastity eminently requires self-command; therefore it has 
 been honored from a very early period in the moral history 
 of civilized man. As a consequence of this, the senseless 
 practice of celibacy has been ranked from a remote pej^od 
 
 *Mr. M'Lennan has given ( Primitive Marriage," 1865, p. 176) a 
 good collection of facts on this head.
 
 MORAL SENSE. 135 
 
 as a virtue. * The hatred of indecency, which appears to 
 as so natural as to be thought innate, and which is so val- 
 uable an aid to chastity, is a modern virtue, appertaining 
 exclusively, as Sir G. Staunton remarks,! to civilized life. 
 This is shown by the ancient religious rites of various 
 nations, by the drawings on the walls of Pompeii, and by 
 the practices of many savages. 
 
 We have now seen that actions are regarded by savages, 
 and were probably so regarded by primeval man, as good or 
 bad, solely as they obviously affect the welfare of the tribe 
 not that of the species, nor that of an individual member 
 of the tribe. This conclusion agrees well with the belief 
 that the so-called moral sense is aboriginally derived from 
 the social instincts, for both relate at first exclusively to 
 the community. 
 
 The chief causes of the low morality of savages, as 
 judged by our standard, are, firstly, the confinement of 
 sympathy to the same tribe. Secondly, powers of reason- 
 ing insufficient to recognize the bearing of many virtues, 
 especially of the self -regarding virtues, on the general wel- 
 fare of the tribe. Savages, for instance, fail to trace the 
 multiplied evils consequent on a want of temperance, 
 chastity, etc. And, thirdly, weak power of self-command; 
 for this power has not been strengthened through long-con- 
 tinued, perhaps inherited, habit, instruction and religion. 
 
 I have entered into the above details on the immorality 
 of savages, J because some authors have recently taken a 
 high view of their moral nature, or have attributed most of 
 their crimes to mistaken benevolence. These authors 
 appear to rest their conclusion on savages possessing those 
 virtues which are serviceable, or even necessary, for the 
 existence of the family and of the tribe qualities which 
 they undoubtedly do possess, and often in a high degree. 
 
 Concluding Remarks. It was assumed formerly by phi- 
 losophers of the derivative! school of morals that the 
 
 *Lecky, "History of European Morals," vol. i, 1869, p. 109. 
 
 f " Embassy to China," vol. ii, p. 348. 
 
 J See on this subject copious evidence in chap, vii, of Sir J. Lub- 
 bock, "Origin of Civilization," 1870. 
 -For instance, Lecky " Hist. European Morals," vol. i, p. 124. 
 
 H This term is used in an able article in the " Westminster Re- 
 view," Oct., 1869, p. 498. For the "greatest happiness principle." 
 see J. S. Mill, Utilitarianism." u 17.
 
 136 THE DESCENT OF MAN. 
 
 foundation of morality lay in a form of Selfishness; but 
 more recently the " greatest happiness principle " has been 
 brought prominently forward. It is, however, more cor- 
 rect to speak of the latter principle as the standard, and 
 not as the motive of conduct. Nevertheless, all the authors 
 whose works I have consulted, with a few exceptions,* 
 write as if there must be a distinct motive for every action, 
 and that this must be associated with some pleasure or dis- 
 pleasure. But man seems often to act impulsively, that is 
 from instinct or long habit, without any consciousness of 
 pleasure, in the same manner as does probably a bee or ant, 
 when it blindly follows its instincts. Under circumstances 
 of extreme peril, as during a fire, when a man endeavors to 
 save a fellow-creature without a moment's hesitation, he 
 can hardly feel pleasure; and still less has he time to reflect 
 on the dissatisfaction which he might subsequently experi- 
 ence if he did not make the attempt. Should he afterward 
 reflect over his own conduct, he would feel that there lies 
 within him an impulsive power widely different from a 
 search after pleasure or happiness; and this seems to be the 
 deeply planted social instinct. 
 
 In the case of the lower animals it seems much more 
 appropriate to speak of their social instincts as having 
 been developed for the general good rather than for the 
 general happiness of the species. The term, general good, 
 may be defined as the rearing of the greatest number of 
 individuals in full vigor and health, with all their faculties 
 perfect, under the conditions to which they are subjected. 
 
 *Mill recognizes (" System of Logic," vol. ii, p, 422) in the clear- 
 est manner, that actions may be performed through habit without 
 the anticipation of pleasure. Mr. H. Sidgwick also, in his essay on 
 Pleasure and Desire (" The Contemporary Review," April 1872, p. 
 671), remarks: "To sum up, in contravention of the doctrine that 
 our conscious active impulses are always directed toward the pro- 
 duction of agreeable sensations in ourselves, I would maintain that 
 we find everywhere in consciousness extra-regarding impulse, di- 
 rected toward something that is not pleasure; that in many cases the 
 impulse is so far incompatible with the self-regarding that the two 
 do not easily co-exist in the same moment of consciousness." A dim 
 feeling that" our impulses do not by any means always arise from any 
 contemporaneous or anticipated pleasure, has, I cannot but think, 
 been one chief cause of the acceptance of the intuitive theory of 
 morality, and of the rejection of the utilitarian or "greatest happi- 
 ness " theory. With respect to the latter theory the standard and 
 the motive of conduct have no doubt often been confused, but they 
 are zeaiiy *n some degree blended. ,
 
 MORAL SENSE. 137 
 
 As the social instincts both of man and the lower animals 
 have no doubt been developed by nearly the same steps, it 
 would be advisable, if found practicable, to use the same 
 definition in both cases, and to take as the standard of 
 morality the general good or welfare of the community, 
 rather than the general happiness; but this definition 
 would perhaps require some limitation on account of 
 political ethics. 
 
 When a man risks his life to save that of a fellow-creat- 
 ure it seems also more correct to say that he acts for the 
 general good rather than for the general happiness of man- 
 kind. No doubt the welfare and the happiness of the 
 individual usually coincide; and a contented, happy tribe 
 will flourish better than one that is discontented and 
 unhappy. We have seen that even at an early period in 
 the history of man the expressed wishes of the community 
 will have naturally influenced to a large extent the conduct 
 of each member; and as all wish for happiness, the ( ' great- 
 est happiness principle " will have become a most impor- 
 tant secondary guide and object; the social instinct, how- 
 ever, together with sympathy (which leads to our regarding 
 the approbation and disapprobation of others), having 
 served as the primary impulse and guide. Thus the re- 
 proach is removed of laying the foundation of the noblest 
 part of our nature in the base principle of selfishness; 
 unless, indeed, the satisfaction which every animal feels, 
 when it follows its proper instincts, and the dissatisfaction 
 felt when prevented be called selfish. 
 
 The wishes and opinions of the members of the same 
 community, expressed at first orally but later by writing 
 also, either form the sole guides of our conduct or greatly 
 re-enforce the social instincts; such opinions, however, have 
 sometimes a tendency directly opposed to these instincts. 
 This latter fact is well exemplified by the Law of Honor, 
 that is, the law of the opinion of our equals and not of all 
 our countrymen. The breach of this law, even when the 
 breach is known to be strictly accordant with true moral- 
 ity, has caused many a man more agony than a real crime. 
 We recognize the same influence in the burning sense of 
 shame which most of us have felt, even after the interval 
 of years, when calling to mind some accidental breach of a 
 trilling, though fixed rule of etiquette. The judgment of 
 the community will generally be guided by some rude
 
 138 THE DESCENT OF MAN. 
 
 experience of what is best in the long run for all the mem- 
 bers; but this judgment will not rarely err from ignorance 
 and weak powers of reasoning. Hence the strangest cus- 
 toms and superstitions, in complete opposition to the trae 
 welfare and happiness of mankind, have become all-power- 
 ful throughout the world. We see this in the horror felt 
 by a Hindoo who breaks his caste, and in many other such 
 cases. It would be difficult to distinguish between the 
 remorse felt by a Hindoo who has yielded to the tempta- 
 tion of eating unclean food from that felt after committing 
 a theft; but the former would probably be the more severe. 
 
 How so many absurd rules of conduct, as well as o 
 many absurd religious beliefs, have originated, we do not 
 know; nor how it is that they have become, in all quarters 
 of the world, so deeply impressed on the minds of men; 
 but it is worthy of remark that a belief constantly incul- 
 cated during the early years of life, while the brain is im* 
 pressible, appears to acquire almost the nature of an 
 instinct; and the very essence of an instinct is that it is 
 followed independently of reason. Neither can we say wny 
 certain admirable virtues, such as the love of truth, are 
 much more highly appreciated bj some savage tribes than 
 by others;* nor, again, why similar differences prevail even 
 among highly civilized nations. Knowing liow firmly 
 fixed many strange customs and superstitions have become, 
 we need feel no surprise that the self-regarding virtues, 
 supported as they are by reason, should now appear to us 
 BO natural as to be thought innate, although they were not 
 Valued by man in his early condition. 
 
 Notwithstanding many sources of doubt, man can gener- 
 ally and readily distinguish between the higher and lower 
 moral rules. The higher are founded on the social 
 instincts, and relate to the welfare of others. They are 
 supported by the approbation of our fellow-men and by 
 reason. The lower rules, though some of them when im- 
 plying self-sacrifice hardly deserve to be called lower, relate 
 chiefly to self, and arise from public opinion, matured by 
 experience and cultivation; for they are not practiced by 
 rude tribes. 
 
 As man advances in civilization, and small tribes are 
 
 *Good instances are given by Mr. Wallace in " Scientific Opinion," 
 Sept. 15, 1869; and more fully in bis "Contributions to the Theory 
 of Natural Selection." 1870 t P. 353.
 
 MORAL SENSE. 139 
 
 united into larger communities, the simplest reason would 
 tell each individual that he ought to extend his social 
 instincts and sympathies to all the members of the same 
 - nation, though personally unknown to him. This point 
 being once reached, there is only an artificial barrier to pre- 
 vent his sympathies extending to the men of all nations 
 and races. If, indeed, such men are separated from him 
 by great differences in appearance or habits, experience 
 unfortunately shows us how long it is, before we look at 
 them as our fellow-creatures. Sympathy beyond the con- 
 fines of man, that is, humanity to the lower animals, seems 
 to be one of the latest moral acquisitions. It is apparently 
 unfelt by savages, except toward their pets. How little 
 the old Romans knew of it is shown by their abhorrent 
 gladiatorial exhibitions. The very idea of humanity, as 
 far as I could observe, was new to most of the Gauchos of 
 the Pampas. This virtue, one of the noblest with which 
 man is endowed, seems to arise incidentally from our sym- 
 pathies becoming more tender and more widely diffused, 
 until they are extended to all sentient beings. As soon as 
 this virtue is honored and practiced by some few men, it 
 spreads through instruction and example to the young, and 
 eventually becomes incorporated in public opinion. 
 
 The highest possible stage in moral culture is when we 
 recognize that we ought to control our thoughts, and 
 " not even in inmost thought to think again the sins that 
 made the past so pleasant to us."* Whatever makes any 
 bad action familiar to the mind renders its performance 
 by so much the easier. As Marcus Aurelius long ago said: 
 " Such as are thy habitual thoughts, such also will be the 
 character of thy mind ; for the soul is dyed by the 
 thoughts."! 
 
 Our great philosopher, Herbert Spencer, has recently 
 explained his views on the moral sense. He says:J " I 
 believe that the experiences of utility organized and con- 
 solidated through all past generations of the human race, 
 have been producing corresponding modifications, which, 
 
 * Tennyson's " Idylls of the King," p. 244. 
 
 f " The Thoughts of the Emperor M. Aurelius Antoninus," Eng. 
 translat., 2d edit., 1869, p. 112. Marcus Aurelius was born A. D. 
 121. - 
 
 t Letter to Mr. Mill in Bain's "Mental and Moral Science," 1868, 
 p. 722,
 
 140 THE DES&ENT OF MAN. 
 
 by continued transmission and accumulation, have become 
 in us certain faculties of moral intuition certain emotions 
 responding to right and wrong conduct, which have no 
 apparent basis in the individual experiences of utility." 
 There is not the least inherent improbability, as it seems co 
 me, in virtuous tendencies being more or less strongly 
 inherited; for. not to mention the various dispositions and 
 habits transmitted by many of our domestic animals to 
 their offspring, I have heard of authentic cases^iu which a 
 desire to steal and a tendency to lie appeared to run in 
 families of the upper ranks; and as stealing is a rare crime 
 in the wealthy classes., we can hardly account by accidental 
 coincidence for the tendency occurring in two or three 
 members of the same family. If bad tendencies are trans- 
 mitted, it is probable that good ones are likewise trans- 
 mitted. That the state of the body by affecting the brain 
 has great influence on the moral tendencies is known 
 to most of those who have suffered from chronic derange- 
 ments of the digestion or liver. The same fact is likewise 
 shown by the "perversion or destruction of the moral 
 sense being often one of the earliest symptoms of mental 
 derangement;" * and insanity is notoriously often inherited. 
 Except through the principle of the transmission of moral 
 tendencies, we cannot understand the differences believed 
 to exist in this respect between the various races of 
 mankind. 
 
 Even the partial transmission of virtuous tendencies 
 would be an immense assistance to the primary impulse 
 derived directly and indirectly from the social instincts. 
 Admitting for a moment that virtuous tendencies are 
 inherited, it appears probable, at least in such cases as 
 chastity, temperance, humanity to .animals, etc., that they 
 become first impressed on the mental organization through 
 habit, instruction and example, continued during several 
 generations in the same family, and in a quite subordinate 
 degree, or not at all, by the individuals possessing such 
 virtues having succeeded best in the struggle for life. My 
 chief source of doubt with respect to any such inheritance, 
 is that senseless customs, superstitions and tastes, such a 
 the horror of a Hindoo for unclean food, ought on the same 
 principle to be transmitted.. I have not met with any 
 
 *Maudsley, "Body and Mind." 1870, p. 60.
 
 MORAL SENSE. HI 
 
 evidence in support of the transmission of superstitious 
 customs or senseless habits, although in itself it is per- 
 haps not less probable than that animals should acquire 
 inherited tastes for certain kinds of food or fear of certain 
 foes. 
 
 Finally the social instincts, which no doubt were acquired 
 by man as by the lower animals for the good of the com- 
 munity, will from the first have given to him some wish to 
 aid his fellows, some feeling of sympathy, and have com- 
 pelled him to regard their approbation and disapprobation. 
 Such impulses will have served him at a very early period 
 as a rude rule of right and wrong. But as man gradually 
 advanced in intellectual power and was enabled to trace the 
 more remote consequences of his actions; as he acquired 
 sufficient knowledge to reject baneful customs and super- 
 stitions; as he regarded more and more not only the wel- 
 fare, but the happiness of his fellow-men; as from habit, 
 following on beneficial experience, instruction and example, 
 his sympathies became more tender and widely diffused, 
 extending to men of all races, to the imbecile, maimed, and 
 other useless members of society, and finally to the lower 
 animals so would the standard of his morality rise higher 
 and higher. And it is admitted by moralists of the deriva- 
 tive school and by some intuitionists, that the standard of 
 morality has risen since an early period in the history of 
 man.* 
 
 As a struggle may sometimes be seen going on between 
 the various instincts of the lower animals, it is not surpris- 
 ing that there should be a struggle in man between his 
 social instincts, with their derived virtues, and his lower, 
 though momentarily stronger impulses or desires. This, as 
 Mr. Galtonf has remarked, is all the less surprising, as man 
 has emerged from a state of barbarism within a compara- 
 tively recent period. After having yielded to some temp- 
 tation we feel a sense of dissatisfaction, shame, repentance, 
 
 * A writer in the " North British Review " (July 1869, p. 531), 
 well capable of forming a sound judgment, expresses himself strongly 
 in favor of this conclusion. Mr. Lecky (" Hist, of Morals," vol. i, p. 
 143) seems to a certain extent to coincide therein. 
 
 f See his remarkable work on "Hereditary Genius," 1869, p. 349. 
 The Duke of Argyll (" Primeval Man," 1869, p. 188) has some good 
 remarks on the contest in man's nature between right and wrong.
 
 142 THE DES&ENT OF MAN. 
 
 or remorse, analogous to the feelings caused by other power- 
 ful instincts or desires, when left unsatisfied or balked. 
 "We compare the weakened impression of a past temptation 
 with the ever present social instincts, or with habits, gained 
 in early youth and strengthened during our whole lives 
 until they have become almost as strong as instincts. If 
 with the temptation still before us we do not yield, it is 
 because either the social instinct or some custom is at the 
 moment predominant, or because we have learned that it 
 will appear to us hereafter the stronger, when compared 
 with the weakened impression of the temptation, and we 
 realize that its violation would cause us suffering. Looking 
 to future generations, there is no cause to fear that the 
 social instincts will grow weaker, and we may expect that 
 virtuous habits will grow stronger, becoming perhaps fixed 
 by inheritance. In this case the struggle between our 
 higher and lower impulses will be less severe, and virtue 
 will be triumphant. 
 
 Summary of the Last Two Chapters. There can be no 
 doubt that the difference between the mind of the lowest 
 man and that of the highest animal is immense. An 
 anthropomorphous ape, if he could take a dispassionate view 
 of his own case, would admit that though he could form 
 an artful plan to plunder a garden though he could use 
 stones for fighting or for breaking open nuts, yet that the 
 thought of fashioning a stone into a tool was quite beyond 
 his scope. Still less, as he would admit, could he follow 
 out a train of metaphysical reasoning, or solve a mathemat- 
 ical problem, or reflect on God, or admire a grand natural 
 scene. Some apes, however, would probably declare that 
 they could and did admire the beauty of the colored skin 
 and fur of their partners in marriage. They would admit, 
 that though they could make other apes understand by 
 cries some of their perceptions and simpler wants, the notion 
 of expressing definite ideas by definite sounds had never 
 crossed their minds. They might insist that they were 
 ready to aid their fellow-apes of the same troop in many 
 ways, to risk their lives for them, and to take charge of 
 their orphans; but they would be forced to acknowledge 
 that disinterested love for all living creatures, the most 
 noble attribute of man, was quite beyond their compre- 
 hension.
 
 SUMMARY. 143 
 
 Nevertheless the difference in mind between man and 
 the higher animals, great as it is, certainly is one of degree 
 and not of kind. We have seen that the senses and intui- 
 tions, the various emotions and faculties, such as love, 
 memory, attention, curiosity, imitation, reason, etc., of 
 which man boasts, may be found in an incipient, or even 
 sometimes in a well-developed condition, in the lower 
 animals. They are also capable of some inherited improve- 
 ment, as we see in the domestic dog compared with the 
 wolf or jackal. If it could be proved that certain high 
 mental powers, such as the formation of general con- 
 cepts, self-consciousness, etc., were absolutely peculiar to 
 man, which seems extremely doubtful, it is not improbable 
 that these qualities are merely the incidental results of 
 other highly-advanced intellectual faculties ; and these 
 again mainly the result of the continued use of a perfect 
 language. At what age does the new-born infant possess 
 the power of abstraction, or become self-conscious and 
 reflect on its own existence ? We cannot answer; nor can 
 we answer in regard to the ascending organic scale. The 
 half-art, half-instinct of language still bears the stamp 
 of its gradual evolution. The ennobling belief in God is 
 not universal with man; and the belief in spiritual agencies 
 naturally follows from other mental powers. The moral 
 sense perhaps affords the best and highest distinction 
 between man and the lower animals; but I need say noth- 
 ing on this head, as I have so lately endeavored to show 
 that the social instincts the prime principle of man's 
 moral constitution* with the aid of active intellectual 
 powers and the effects of habit, naturally lead to the golden 
 rule, " As ye would that men should do to you, do ye to 
 them likewise;" and this lies at the foundation of morality. 
 
 In the next chapter I shall make some few remarks on the 
 probable steps and means by which the several mental 
 and moral faculties of man have been gradually evolved. 
 That such evolution is at least possible, ought not to be 
 denied, for we daily see these faculties developing in every 
 infant; and we may trace a pefect gradation from the mind 
 of an utter idiot, lower than that of an animal low in the 
 scale, to the mind of a Newton. 
 
 *"The Thoughts of Marcus Aurelius," etc., p. 139.
 
 144 THE DESGENT OF MAjf. 
 
 CHAPTER V. 
 
 ON THE DEVELOPMENT OF THE INTELLECTUAL AND 
 
 MORAL FACULTIES DURING PRIMEVAL AND 
 
 CIVILIZED TIMES. 
 
 Advancement of the intellectual powers through natural selection 
 Importance of imitation Social and moral faculties Their 
 development within the limits of the same tribe Natural 
 selection as affecting civilized nations Evidence that civilized 
 nations were once barbarous. 
 
 THE subjects to be discussed in this chapter are of the 
 highest interest, but are treated by me in an imperfect and 
 fragmentary manner. Mr. Wallace, in an admirable paper 
 before referred to,* argues that man, after he had partially 
 acquired those intellectual and moral faculties which dis- 
 tinguish him from the lower animals, would have been but 
 little liable to bodily modifications through natural selec- 
 tion or any other means. For man is enabled through his 
 mental faculties " to keep with an unchanged body in har- 
 mony with the changing universe." He has great power 
 of adapting his habits to new conditions of life. He 
 invents weapons, tools, and various stratagems to procure 
 food and to defend himself. When he migrates into a 
 colder climate he uses clothes, builds sheds, and makes 
 fires; and by the aid of fire cooks food otherwise indigesti- 
 ble. He aids his fellow-men in many ways, and anticipates 
 future events. Even at a remote period he practiced some 
 division of labor. 
 
 The lower animals, on the other hand, must have their 
 bodily structure modified in order to survive under greatly 
 changed conditions. They must be rendered stronger, or 
 acquire more effective teeth or claws, for defense against 
 new enemies; or they must be reduced in size, so as to 
 
 * "Anthropological Review," May, 1864, p. 158.
 
 INTELLECTUAL FACULTIES. 145 
 
 escape detection and danger. When they migrate into a 
 colder climate, they must become clothed with thicker fur, 
 or have their constitutions altered. If they fail to be thus 
 modified, they will cease to exist. 
 
 The case, however, is widely different, as Mr. "\\ aiiace 
 has with justice insisted, in relation to the intellectual and 
 moral faculties of man. These faculties are variable; and 
 we have every reason to believe that the variations tend to 
 be inherited. Therefore, if they were formerly of high 
 importance to primeval man and to his ape-like progenitors, 
 they would have been perfected or advanced through 
 natural selection. Of the high importance of the intel- 
 lectual faculties there can be no doubt, for man mainly 
 owes to them his predominant position in the world. We 
 can see, that in the rudest state of society, the individuals 
 who were the most sagacious, who invented and used the 
 best weapons or traps, and who were best able to defend 
 themselves, would rear the greatest number of offspring. 
 The tribes, which included the largest number of men thus 
 endowed, would increase in number and supplant other 
 tribes. Numbers depend primarily on the means of sub- 
 sistence, and this depends partly on the physical nature of 
 the country, but in a much higher degree on the arts 
 which are there practiced. As a tribe increases and is vic- 
 torious, it is often still further increased by the absorption 
 of other tribes. * The stature and strength of the men of a 
 tribe are likewise of some importance for its success, and 
 these depend in part on the nature and amount of the 
 food which can be obtained. In Europe the men of the 
 Bronze period were supplanted_by a race more powerful, 
 and, judging from their sword-Handles, with larger hands;f 
 but their success was probably still more due to their 
 superiority in the arts. 
 
 All that we know about savages, or may infer from their 
 traditions and from old monuments, the history of which 
 is quite forgotten by the present inhabitants, show that 
 from the remotest times successful tribes have supplanted 
 other tribes. Eelics of extinct or forgotten tribes have been 
 discovered throughout the civilized regions of the earth, on 
 
 * After a time the members or tribes which are absorbed into 
 another" tribe assume, as Sir Henry Maine remarks ("Ancient Law," 
 1861, p. 131), that they are the co-descendants of the same ancestors. 
 
 iMorlot, "Soc. Yaiid. Sc. Nat," 1860, u. 294
 
 X46 THE DESCENT OF MAN. 
 
 the wild plains of America, and on the isolated islands in 
 the Pacific Ocean. At the present day civilized nations 
 are everywhere supplanting barbarous nations, excepting 
 where the climate opposes a deadly barrier; and they suc- 
 ceed mainly, though not exclusively, through their arts, 
 which are the products of the intellect. It is, therefore, 
 highly probable that with mankind the intellectual facul* 
 ties have been mainly and gradually perfected through 
 natural selection; and this conclusion is sufficient for our 
 purpose. Undoubtedly it would be interesting to trace the 
 development of each separate faculty from the state in 
 which it exists in the lower animals to that in which it 
 exists in man; but neither my ability nor knowledge per- 
 mits the attempt. 
 
 It deserves notice that as soon as the progenitors of man 
 became social (and this probably occurred at a very early 
 period), the principle of imitation and reason and experi- 
 ence would have increased and much modified the intel- 
 lectual powers in a way, of which we see only traces in the 
 lower animals. Apes are much given to imitation, as are 
 the lowest savages; and the simple fact previously referred 
 to, that after a time no animal can be caught in the same 
 place by the same sort of trap, shows that animals learn by 
 experience and imitate the caution of others. Now, if some 
 one man in a tribe, more sagacious than the others, invented 
 a new snare or weapon, or other means of attack or defense, 
 the plainest self-interest, without the assistance of much 
 reasoning power, would prompt the other members to imi- 
 tate him; and all would thus profit. The habitual practice 
 of each new art must likewise in some slight degree 
 strengthen the intellect. If the new invention were an 
 important one, the tribe would increase in number, spread, 
 and supplant other tribes. In a tribe thus rendered more 
 numerous there would always be a rather greater chance of 
 the birth of other superior and inventive members. If 
 such men left children to inherit their mental superiority, 
 the chance of the birth of still more ingenious members 
 would be somewhat better, and in a very small tribe decid- 
 edly better. Even if they left no children, the tribe would 
 still include their blood-relations; and it has been ascer- 
 tained by agriculturists* that by preserving and breeding 
 
 * I have given instances in iny " Variation of Animals under Do- 
 mestication," vol. ii, p. 196.
 
 MORAL FACULTIES. 147 
 
 from the family of an animal which when slaughtered was 
 found to be valuable, the desired character has been 
 obtained. 
 
 Turning now to the social and moral faculties. In order 
 that primeval men, or the ape-like progenitors of man, 
 should become social, they must have acquired the same 
 instinctive feelings, which impel other animals to live in a 
 body; and they no doubt exhibited the same general dispo- 
 sition. They would have felt uneasy when separated from 
 their comrades, for whom they would have felt some degree 
 of love; they would have warned each other of danger, and 
 have given mutual aid in attack or defense. All this im- 
 plies some degree of sympathy, fidelity and courage. Such 
 social qualities, the paramount importance of which to the 
 lower animals is disputed by no one, were no doubt acquired 
 by the progenitors of man in a similar manner, namely, 
 through natural selection, aided by inherited habit. When 
 two tribes of primeval man, living in the same country, 
 came into competition, if (other circumstances being equal) 
 the one tribe included a great number of courageous, sym- 
 pathetic and faithful members, who were always ready to 
 warn each other of danger, to aid and defend each other, 
 this tribe would succeed better and conquer the other. Let 
 it be borne in mind how all-important in the never-ceasing 
 wars of savages, fidelity and courage must be. The advan- 
 tage which disciplined soldiers have over undisciplined 
 hordes follows chiefly from the confidence which each man 
 feels in his comrades. Obedience, as Mr. Bagehot has well 
 shown,* is of the highest value, for any form of government 
 is better than none. Selfish and contentious people will 
 not cohere, and without coherence nothing can be effected. 
 A tribe rich in the above qualities would spread and be 
 victorious over other tribes; but in the course of time it 
 would judging from all past history, be in its turn over- 
 come by some other tribe still more highly endowed. Thus 
 the social and moral qualities would tend slowly to advance 
 and be^diffused throughout the world. 
 
 But it may be asked, how within the limits of the same 
 tribe did a large number of members first become endowed 
 
 * See a remarkable series of articles on " Physics and Politics," in 
 the " Fortnightly Review," Nov., 1867; April 1, 1868; July 1, 1869, 
 since separately published
 
 148 THE DESCENT OF MAN. 
 
 with these social and moral qualities, and how was the 
 standard of excellence raised? It is extremely doubtful 
 whether the offspring of the more sympathetic and benevo- 
 lent parents, or of those who were the most faithful to 
 their comrades, would be reared in greater numbers than 
 the children of selfish and treacherous parents belonging to 
 the same tribe. He who was ready to sacrifice his life, as 
 many a savage has been, rather than betray his comrades, 
 would often leave no offspring to inherit his noble nature. 
 The bravest men, who were always willing to come to the 
 front in war, and who freely risked their lives for others, 
 would on an average perish in larger numbers than other 
 men. Therefore it hardly seems probable, that the number 
 of men gifted with such virtues, or that the standard of 
 their excellence could be increased through natural selec- 
 tion, that is, by the survival of the fittest ; for we are not 
 here speaking of one tribe being victorious over another. 
 
 Although the circumstances, leading to an increase in 
 the number of those thus endowed within the same tribe 
 are too complex to be clearly followed out we can trace 
 some of the probable steps. In the first place, as the rea- 
 soning powers and foresight of the members became im- 
 proved, each man would soon learn that if he aided his 
 fellow-men he would commonly receive aid in return. 
 From this IOAV motive he might acquire the habit of aiding 
 his fellows; and the habit of performing benevolent actions 
 certainly strengthens the feeling of sympathy which gives 
 the first impulse to benevolent actions. Habits, more- 
 over, followed during many generations probably tend to 
 be inherited. 
 
 But another and much more powerful stimulus to the 
 development of the social virtues is afforded by the praise 
 and the blame of our fellow-men. To the instinct of 
 sympathy, as we have already seen, it is primarily due that 
 we habitually bestow both praise and blame on others, 
 while we love the former and dread the latter when applied 
 to ourselves; and this instinct no doubt was originally 
 acquired, like all the other social instincts, through nat- 
 ural selection. At how early a period the progenitors of 
 man in the course of their development became capable of 
 feeling and being impelled by the praise or blame of their 
 fellow-creatures we cannot of course say. But it appears 
 that even dogs appreciate encouragement, praise, and
 
 MORAL FACULTIES. 149 
 
 blame. The rudest savages feel the sentiment of glory, as 
 they clearly show by preserving the trophies of their 
 prowess, by their habit of excessive boasting, and even by 
 the extreme care which they take of their personal appear- 
 ance and decorations; for unless they regarded the opinion 
 of their comrades such habits Avould be senseless. 
 
 They certainly feel shame at the breach of some of their 
 lesser rules, and apparently remorse, as shown by the case 
 of the Australian who grew thin and could not rest from 
 having delayed to murder some other woman so as to pro- 
 pitiate his dead wife's spirit. Though I have not met with 
 any other recorded case, it is scarcely credible that a savage 
 who will sacrifice his life rather than betray his tribe, or one 
 who will deliver himself up as a prisoner rather than break 
 his parole,* would not feel remorse in his inmost soul if he 
 had failed in a duty which he held sacred. 
 
 We may therefore conclude that primeval man, at a very 
 remote period, was influenced by the praise and blame of 
 his fellows. It is obvious that the members of the same 
 tribe would approve of conduct which appeared to them to 
 be for the general good, and would reprobate that which 
 appeared evil. To do good unto others to do unto others as 
 ye would they should do unto you is the foundation stone 
 of morality. It is, therefore, hardly possible to exaggerate 
 the importance during rude times of the love of praise and 
 the dread of blame. A man who was not impelled by any 
 deep, instinctive feeling, to sacrifice his life for the good 
 of others, yet was roused to such actions by a sense of 
 glory, would by his example excite the same wish for glory 
 in other men, and Avould strengthen by exercise the noble 
 feeling of admiration. He might thus do far more good to 
 his tribe than by begetting offspring with a tendency to 
 inherit his own high character. 
 
 With increased experience and reason, man perceives the 
 more remote consequences of his actions, and the self -regard- 
 ing virtues, such as temperance, chastity, etc., which during 
 early times are, as we have before seen, utterly disregarded, 
 come to be highly esteemed or even held sacred. I need 
 not, however, repeat what I have said on this head in the 
 fourth chapter. Ultimately our moral sense or conscience 
 becomes a highly complex sentiment originating in the 
 
 * Mr. Wallace gives cases in Ms " Contributions to the Theory of 
 Natural Selection," 1870, p. 354.
 
 150 THE DESCENT OF MAN. 
 
 social instincts, largely guided by the approbation of our 
 fellow-men, ruled by reason, self-interest, and in later 
 times by deep religious feelings, and confirmed by instruc- 
 tion and habit. 
 
 It must not be forgotten that although a high standard 
 of morality gives but a slight or no advantage to each 
 individual man and his children over the other men of the 
 same tribe, yet that an increase in the number of well- 
 endowed men and an advancement in the standard of 
 morality will certainly give an immense advantage to one 
 tribe over another. A tribe including many members who, 
 from possessing in a high degree the spirit of patriotism, fidel- 
 ity, obedience, courage and sympathy, were always ready to 
 aid one another, and to sacrifice themselves for the common 
 good, would be victorious over most other tribes; and this 
 would be natural selection. At all times throughout the 
 world tribes have supplanted other tribes; and as morality 
 is one important element in their success, the standard of 
 morality and the number of well-endowed men will thus 
 everywhere tend to rise and increase. 
 
 It is, however, very difficult to form any judgment why 
 one particular tribe and not another has been successful 
 and has risen in the scale of civilization. Many savages 
 are in the same condition as when first discovered several 
 centuries ago. As Mr. Bagehot has remarked, we are apt 
 to look at progress as normal in human society; but history 
 refutes this. The ancients did not even entertain the idea, 
 nor do the Oriental nations at the present day. According 
 to another high authority, Sir Henry Maine,* ' ' the greatest 
 part of mankind has never shown a particle of desire that its 
 civil institutions should be improved." Progress seems to 
 depend on many concurrent favorable conditions, far too 
 complex to be followed out. But it has often been remarked, 
 that a cool climate, from leading to industry and to the 
 various arts, has been highly favorable thereto. The Esqui- 
 maux, pressed by hard necessity, have succeeded in many 
 ingenious inventions, but their climate has been too severe 
 for continued progress. Nomadic habits, whether over wide 
 plains, or through the dense forests of the tropics, or along 
 the shores of the sea, have in every case been highly detri- 
 mental. While observing the barbarous inhabitants of 
 
 *" Ancient Law," 1861, p. 22. For Mr. Bagehot's remarks, 
 " Fortnightly Review," April 1, 1868, p. 452.
 
 CIVILIZED NATIONS. 151 
 
 Tierra del Fuego, it struck me that the possession of some 
 property, a fixed abode, and the union of many families under 
 a chief, were the indispensable requisites for civilization. 
 Such habits almost necessitate the cultivation of the ground; 
 and the first steps in cultivation would probably result, as 
 I have elsewhere shown,* from some such accident as the 
 seeds of a fruit-tree falling on a heap of refuse, and pro- 
 lucing an unusually fine variety. The problem, however, 
 of the first advance of savages toward civilization is at pres- 
 ent much too difficult to be solved. 
 
 Natural Selection as Affecting Civilized Nations. I have 
 hitherto only considered the advancement of man from a 
 semi-human condition to that of the modern savage. But 
 some remarks on the action of natural selection on civilized 
 nations may be worth adding. This subject has been ably 
 discussed by Mr. W. E. Greg,f and previously by Mr. Wal- 
 lace and Mr. Galton. Most of my remarks are taken from 
 these three authors. With savages, the weak in body or 
 mind are soon eliminated; and those that survive commonly 
 exhibit a vigorous state of health. We civilized men, on 
 khe other hand, do our utmost to check the process of elim- 
 ination; we build asylums for the imbecile, the maimed, 
 and the sick; we institute poor-laws; and our medical men 
 exert their utmost skill to save the life of every one to the 
 last moment. There is reason to believe that vaccination 
 has preserved thousands, who from a weak constitution 
 would formerly have succumbed to small-pox. Thus the 
 weak members of civilized societies propagate their kind. 
 No one who has attended to the breeding of domestic ani- 
 
 *"The Variation of Animals and Plants under Domestication," 
 Vol. i, p. 309. 
 
 f " Eraser's Magazine," Sept., 1868, p. 353. This article seems to 
 have struck many persons, and lias given rise to two remarkable 
 essays and a rejoinder in the "Spectator," Oct. 3 and 17, 1868. It 
 has also been dftcussed in the "Q. Journal of Science," 1869, p. 152, 
 and by Mr. Lawson Tait in the " Dublin Q. Journal of Medical 
 Science," Feb., 1869, and by Mr. E. Ray Lankester in his "Com- 
 parative Longevity," 1870, p. 128. Similar views appeared pre- 
 viously in the " Australasian," July 13, 1867. I have borrowed ideas 
 from several of these writers. 
 
 \ For Mr. Wallace, see " Anthropolog. Review," as before cited. 
 Mr. Galton in " Macrnillan's Magazine," Aug., 1865, p. 318; also his 
 great work, "Hereditary Genius," 1870.
 
 152 THE DESCENT OF MAN. 
 
 mals will doubt that this must be highly injurious to the 
 race of man. It is surprising how soon a want of care, or 
 care wrongly directed, leads to the degeneration of a domes- 
 tic race; but excepting in the case of man himself, hardly 
 any one is so ignorant as to allow his worst animals to 
 breed. 
 
 The aid which we feel impelled to give to the helpless is 
 mainly an incidental result of the instinct of sympathy, 
 which was originally acquired as part of the social instincts, 
 but subsequently rendered, in the manner previously indi- 
 cated, more tender and more widely diffused. Nor could 
 we check our sympathy, even at the urging of hard reason, 
 without deterioration in the noblest part of our nature. 
 The surgeon may harden himself while performing an oper- 
 ation, for he knows that he is acting for the good of his 
 patient; but if we were intentionally to neglect the weak 
 and helpless, it could only be for a contingent benefit, with 
 an overwhelming present evil. We must therefore bear the 
 undoubtedly bad effects of the weak surviving and propa- 
 gating their kind; but there appears to be at least one check 
 in steady action, namely, that the weaker and inferior 
 members of society do not marry so freely as the sound; and 
 this check might be indefinitely increased by the weak in 
 body or mind refraining from marriage, though this is more 
 to be hoped for than expected. 
 
 In every country in which a large standing army is kept 
 up, the finest young men are taken by the conscription or 
 are enlisted. They are thus exposed to early death during 
 war, are often tempted into vice, and are prevented from 
 marrying during the prime of life. On the other hand, the 
 shorter and feebler men, with poor constitutions, are left at 
 home, and consequently have a much better chance of 
 marrying and propagating their kind.* 
 
 Man accumulates property and bequeaths it to his chil- 
 dren, so that the children of the rich have an advantage 
 over the poor in the race for success, independently of 
 bodily or mental superiority. On the other hand, the 
 children of parents who are short-lived, and are therefore 
 on an average deficient in health and vigor, come into their 
 property sooner than other children, and will be likely 
 
 *Prof. H. Fick (" Einfluss der Xaturwissenschaft auf das Recht," 
 June, 1872) has some good remarks on this head, and on other such 
 points.
 
 CIVILIZED NATIONS. 153 
 
 to marry earlier, and leave a larger number of offspring to 
 inherit their inferior constitutions. But the inheritance of 
 property by itself is very far from an evil; for without the 
 accumulation of capital the arts could not progress; and it 
 is chiefly through their power that the civilized races have 
 extended, and are now everywhere extending their range, 
 so as to take the place of the lower races. Nor does the 
 moderate accumulation of wealth interfere with the process 
 of selection. When a poor man becomes moderately rich, 
 his children enter trades or professions in which there is 
 struggle enough, so that the able in body and mind succeed 
 best. The presence of a body of well-instructed men, who 
 have not to labor for their daily bread, is important to a 
 degree which cannot be overestimated; as all high intel- 
 lectual work is carried on by them, and on such work, 
 material progress of all kinds mainly depends, not to men- 
 tion other and higher advantages. No doubt wealth when 
 very great tends to convert men into useless drones, but 
 their number is never large; and some degree of elimina- 
 tion here occurs, for we daily see rich men, who happen to 
 be fools or profligates, squandering away their wealth. 
 
 Primogeniture with entailed estates is a more direct evil, 
 though it may formerly have been a great advantage by tho 
 creation of a dominant class, and any government is better 
 than none. Most eldest sons, though they may be weak in 
 body or mind, marry, while the younger sons, however 
 superior in these respects, do not so generally marry. Nor 
 can worthless eldest sons with entailed estates squander 
 their wealth. But here, as elsewhere, the relations of 
 civilized life are so complex that some compensatory checks 
 intervene. The men who are rich through primogeniture 
 are able to select generation after generation the more 
 beautiful and -charming women; and these must generally 
 be healthy in body and active in mind. The evil conse- 
 quences, such as they may be, of the continued preserva- 
 tion of the same line of descent, without any selection, are 
 checked by men of rank always wishing to increase their 
 wealth and power ; and this they effect by marrying 
 heiresses. But the daughters of parents who have produced 
 single children, are themselves, as Mr. Galton * has shown, 
 apt to be sterile; and thus noble families are continually 
 
 * "Hereditary Genius," 1870, pp. 332-140.
 
 154 THE DESCENT OF MAN. 
 
 cut off in the direct line, and their wealth flows into some 
 side channel ; but unfortunately this channel is not 
 determined by superiority of any kind. 
 
 Although civilization thus checks in many ways the action 
 of natural selection, it apparently favors the better develop- 
 ment of the body, by means of good food and the freedom 
 from occasional hardships. This may be inferred from 
 civilized men having been found, wherever compared, to be 
 physically stronger than savages. * They appear also to have 
 equal powers of endurance, as has been proved in many 
 adventurous expeditions. Even the great luxury of the 
 rich can be but little detrimental; for the expectation of 
 life of our aristocracy, at all ages and of both sexes, is very 
 little inferior to that of healthy English lives in the lower 
 
 We will now look to the intellectual faculties. If in 
 each grade of society the members were divided into two 
 equal bodies, the one including the intellectually superior 
 and the other the inferior, there can be little doubt that the 
 former would succeed best in all occupations, and rear a 
 greater number of children. Even in the lowest walks of 
 life, skill and ability must be of some advantage; though 
 in many occupations, owing to the great division of labor, 
 a very small one. Hence in civilized nations there will be 
 some tendency to an increase both in the number and in 
 the standard of the intellectually able. But I do not wisli 
 to assert that this tendency may not be more than counter, 
 balanced in other ways, as by the multiplication of the reck- 
 less and improvident; but even to such as these, ability 
 must be some advantage. 
 
 It has often been objected to views like the foregoing, 
 that the most eminent men who have ever lived have left 
 ,no offspring to inherit their great intellect. Mr. Galton 
 'says:t " I regret I am unable to solve the simple question 
 whether, and how far, men and women who are prodigies 
 of genius are infertile. I have, however, shown that meu 
 of eminence are by no means so." Great lawgivers, th 
 
 * Quatrefages, "Revue des Cours Scientifiques," 1867-68, p. 659. 
 
 f See the fifth and sixth columns, compiled from good authorities, 
 in the table given in Mr. E. R. Lankester's " Comparative Longev 
 ity,"1870, p. 115. 
 
 J " Hereditary Genius," 1870, p. 330.
 
 CIVILIZED NATIONS. 155 
 
 founders of beneficent religions, great philosophers and dis- 
 coverers in science, aid the progress of mankind in a far 
 higher degree by their works than by leaving a numerous 
 progeny. In the case of corporeal structures, it is the 
 selection of the slightly better -endowed and the elimination 
 of the slightly less well-endowed individuals, and not 
 the preservation of strongly-marked and rare anomalies, 
 that leads to the advancement of a species.* So it will be 
 with the intellectual faculties, since the somewhat abler 
 men in each grade of society succeed rather better than the 
 less able, and consequently increase in number, if not other- 
 wise prevented. When in any nation the standard of intel- 
 lect and the number of intellectual men have increased, we 
 may expect from the law of the deviation from an average, 
 that prodigies of genius will, as shown by Mr. Galton, 
 appear somewhat more frequently than before. 
 
 In regard to the moral qualities, some elimination of the 
 worst dispositions is always in progress even in the most 
 civilized nations. Malefactors are executed, or imprisoned 
 for long periods, so that they cannot freely transmit their 
 bad qualities. Melancholic and insane persons are confined 
 or commit suicide. Violent and quarrelsome men often 
 come to a bloody end. The restless who will not follow- 
 any steady occupation and this relic of barbarism is a 
 great check to civilization! emigrate to newly-settled 
 countries, where they prove useful pioneers. Intemperance 
 is so highly destructive that the expectation of life of the 
 intemperate at the age of thirty for instance, is only 13.8 
 years; while for the rural laborers of England at the same 
 age it is 40.59 years. J Profligate women bear few children, 
 and profligate men rarely marry; both suffer from disease. 
 In the breeding of domestic animals, the elimination of 
 those individuals, though few in number, which are in any 
 marked manner inferior, is by no means an unimportant 
 element toward success. This especially holds good with 
 injurious characters which tend to reappear through rever- 
 sion, such as blackness in sheep; and with mankind some 
 
 * " Origin of Species" (fifth edition, 1869), p. 104. 
 
 f " Hereditary Genius," 1870, p. 347. 
 
 JE. Ray-Lankester, " Comparative Longevity," 1870, p. 115. Th 
 table of the intemperate is from Nelson's "Vital Statistics." In 
 regard to profligacy, see Dr. Farr, " Influence of Marriage on Mor- 
 tality," "Nat. Assoc. for the Promotion of Social Science,** 1858.
 
 158 THE DESCENT OF MAN. 
 
 of the worst dispositions, which occasionally without any 
 assignable cause make their appearance in families, may 
 perhaps be reversions to a savage state, from which we are 
 not removed by very many generations. This view seems 
 indeed recognized in the common expression that such men. 
 are the black sheep of the family. 
 
 With civilized nations, as far as an advanced standard of 
 morality, and an increased number of fairly good men are 
 concerned, natural selection apparently effects but little; 
 though the fundamental social instincts were originally 
 thus gained. But I have already said enough, while treat- 
 ing of the lower races, on the causes which lead to the 
 advance of morality, namely, the approbation of our fellow- 
 men the strengthening of our sympathies by habit exam- 
 ple and imitation reason experience, and even self-inter- 
 est instruction during youth, and religious feelings. 
 
 A most important obstacle in civilized countries to an 
 increase in the number of men of a superior class has been 
 strongly insisted on by Mr. Greg and Mr. Galton,* namely, 
 the fact that the very poor and reckless, who are often 
 degraded by vice, almost invariably marry early, while the 
 careful and frugal, who are generally otherwise virtuous, 
 marry late in life, so that they may be able to support 
 themselves and their children in comfort. Those who 
 marry early produce within a given period not only a 
 greater number of generations, but, as shown by Dr. Dun- 
 can, f they produce many more children. The children, 
 moreover, that are born by mothers during the prime of 
 life are heavier and larger, and therefore probably more 
 vigorous, than those born at other periods. Thus the 
 reckless, degraded, and often vicious members of so- 
 ciety, tend to increase at a quicker rate than 
 the provident and generally virtuous members. Or, as Mr. 
 Greg puts the case: "The careless, squalid, unaspiring 
 Irishman multiplies like rabbits; the frugal, foreseeing, 
 
 *" Eraser's Magazine," Sept., 1868, p. 353. " Macmillan's Maga- 
 zine," Aug., 1865, p. 318. The Rev. F. W. Farrar (" Fraser's Mag.," 
 Aug., 1870, p. 264) takes a different view. 
 
 f " On the Laws of the Fertility of Women," in " Transact. Royal 
 Soc.," Fxiinburgh, vol. xxiv. p. 287; now published separately under 
 the title of "Fecundity, Fertility and Sterility," 1871. See, also, 
 Mr. Galton, "Hereditary Genius," pp. 353-357, for observations to 
 the above effect.
 
 CIVILIZED NATIONS. 157 
 
 self-respecting, ambitious Scot; stern in his morality, 
 spiritual in his faith, sagacious and disciplined in his intel- 
 ligence, passes his best years in struggle and in celibacy, 
 marries late, and leaves few behind him. Given a land 
 originally peopled by a thousand Saxons and a thousand 
 Celts and in a dozen generations five-sixths of the popu- 
 lation would be Celts, but five-sixths of the property, of 
 the power, of the intellect, would belong to the one-sixth 
 of Saxons that remained. In the eternal ( struggle for ex- 
 istence ' it would be the inferior and less favored race that 
 had prevailed and prevailed by virtue not of its good 
 qualities but of its faults." 
 
 There are, however, some checks to this downward ten- 
 dency. We have seen that the intemperate suffer from a 
 high rate of mortality, and the extremely profligate leave 
 few offspring. The poorest classes crowd into towns, and 
 it has been proved by Dr. Stark from the statistics of ten 
 years in Scotland* that at all ages the death rate is higher 
 in towns than in rural disticts, " and during the first five 
 years of life the town death rate is almost exactly double 
 that of the rural districts. " As these returns include both 
 the rich and the poor, no doubt more than twice the 
 number of births would be requisite to keep up the number 
 of the very poor inhabitants in the towns relatively to those 
 in the country. With women, marriage at too early an 
 age is highly injurious; for it has been found in France 
 that " twice as many wives under twenty die in the year 
 as died out of the same number of the unmarried." The 
 mortality, also, of husbands under twenty is " excessively 
 high,"f but what the cause of this may be seems doubtful. 
 Lastly, if the men who prudently delay marrying until 
 they can bring up their families in comfort were to select, 
 as they often do, women in the prime of life, the rate of 
 increase in the better class would be only slightly lessened. 
 
 It was established from an enormous body of statistics, 
 taken during 1853, that the unmarried men throughout 
 Prance, between the ages of twenty and eighty, die in a 
 
 * " Tenth Annual Report of Births, Deaths," etc., in Scotland, 
 1867, jk 29. 
 
 f These,quotations are taken from our highest authority on such 
 questions, namely, Dr. Farr. in his paper " On the Influence of Mar- 
 riage on the Mortality of the French People," read before the Nat 
 Assoc. for the Promotion of Social Science, 1858
 
 158 THE DESCENT OF MAN. 
 
 much larger proportion than the married; for instance, out 
 of every 1,000 unmarried men, between the ages of twenty 
 and thirty, 11.3 annually died, while of the married only 
 6.5 died.* A similar law was proved to hold good, during 
 the years 1863 and 18G4, with the entire population 
 above the age of twenty in Scotland; for instance, out 
 of every 1,000 unmarried men between the ages of 
 twenty and thirty, 14.97 annually died, while of the mar- 
 ried only 7.24 died, that is less than half.f Dr. Stark 
 remarks on this: " Bachelorhood is more destructive 
 to life than the most unwholesome trades, or than 
 residence in an unwholesome house or district where there 
 has never been the most distant attempt at sanitary improve- 
 ment." He considers that the lessened mortality is the 
 direct result of "marriage, and the more regular domestic 
 habits which attend that state." He admits, however, that 
 the intemperate, profligate, and criminal classes, whose 
 duration of life is low, do not commonly marry; and it 
 must likewise be admitted that men with a weak constitu- 
 tion, ill-health, or any great infirmity in body or mind, will 
 often not wish to marry, or will be rejected. Dr. Stark 
 seems to have come to the conclusion that marriage in 
 itself is a main cause of prolonged life, from finding that 
 aged married men still have a considerable advantage in 
 this respect over the unmarried of the same advanced age; 
 but every one must have known instances of men, who with 
 weak health during youth did not marry, and yet have sur- 
 vived to old age, though remaining weak, and therefore 
 always with a lessened chance of life or of marrying. There 
 is another remarkable circumstance which seems to sup- 
 port Dr. Stark's conclusion, namely, that widows and 
 widowers in France suffer in comparison with the married 
 a very heavy rate of mortality; but Dr. Farr attributes this 
 to the poverty and evil habits consequent on the disruption 
 of the family and to grief. On the whole we may conclude 
 with Dr. Farr that the lesser mortality of married than of 
 
 * Dr. Farr, ibid. The quotations given below are extracted from 
 the same striking paper. 
 
 f I have taken the mean of the quinquennial means, given in " The 
 Tenth Annual Report of Births, Deaths, etc., in Scotland," 1867- 
 The quotation from Dr. Stark is copied from an article in the " Daily 
 News," Oct. 17, 1868. which Dr. Farr considers very carefully 
 written.
 
 CIVILIZED NATIONS. 159 
 
 unmarried men, which seems to be a general law, "is 
 mainly due to the constant elimination of imperfect types, 
 and to the skillful selection of the finest individuals out of 
 each successive generation;" the selection relating only to 
 the marriage state, and acting on all corporeal, intellectual, 
 and moral qualities.* We may, therefore, infer that sound 
 and good men who out of prudence remain for a time 
 unmarried do not suffer a high rate of mortality. 
 
 If the various checks specified in the two last paragraphs, 
 and perhaps others as yet unknown, do not prevent the 
 reckless, the vicious and otherwise inferior members of 
 society from increasing at a quicker rate than the better 
 class of men, the nation will retrograde, as has too often 
 occurred in the history of the world. We must remember 
 that progress is no invariable rule. It is very difficult to 
 say why one civilized nation rises, becomes more powerful, 
 and spreads more widely, than another; or why the same 
 nation progresses more quickly at one time than at another. 
 We can only say that it depends on an increase in the actual 
 number of the population, on the number of the men 
 endowed with high intellectual and moral faculties, as well 
 as on their standard of excellence. Corporeal structure 
 appears to have little influence, except so far as vigor of 
 body leads to vigor of mind. 
 
 It has been urged by several writers that as high intellec- 
 tual powers are advantageous to a nation, the old Greeks, 
 who stood some grades higher in intellect than any race that 
 has ever existed, f ought, if the power of natural selection 
 were real, to have risen still higher in the scale, increased 
 in number, and stocked the whole of Europe. Here we* 
 have the tacit assumption, so often made with respect to 
 corporeal structures, that there is some innate tendency 
 toward continued development in mind and body. But 
 development of all kinds depends on many concurrent 
 favorable circumstances. Natural selection acts only tenta- 
 tively. Individuals and races may have acquired certain 
 indisputable advantages, and yet have perished from failing 
 
 *Dr. Duncan remarks ("Fecundity, Fertility," etc., 1871, p. 334) 
 on this subject: " At every age the healthy and beautiful go over 
 froin the unmarried side to the married, leaving the unmarried 
 oolumus'crowded with the sickly and unfortunate." 
 
 f See the ingenious and original argument on this subject by Mr. 
 Galton, " Hereditary Genius," pp. 340-343.
 
 160 THE DESCENT OF MAN. 
 
 in other characters. The Greeks may have retrograded 
 from a want of coherence between the many small states, 
 from the small size of their whole country, from the 
 practice of slavery, or from extreme sensuality; for they did 
 not succumb until " they were enervated and corrupt to 
 the very core."* The western nations of Europe, who now 
 so immeasurably surpass their former savage progenitors 
 and stand at the summit of civilization, owe little or none 
 of their superiority to direct inheritance from the old 
 Greeks, though they owe much to the written works of that 
 wonderful people. 
 
 Who can positively say why the Spanish nation, so domi- 
 nant at one time, has been distanced in the race. The 
 awakening of the nations of Europe from the dark ages is 
 a still more perplexing problem. At that early period, as 
 Mr. Galtou has remarked, almost all the men of a gentle 
 nature, those given to meditation or culture of the mind, 
 had no refuge except in the bosom of a Church which 
 demanded celibacy; f and this could hardly fail to have had 
 a deteriorating influence on each successive generation. 
 During this same period the Holy Inquisition selected with 
 extreme care the freest and boldest men in order to burn or 
 imprison them. In Spain alone some of the best men 
 those who doubted and questioned, and without doubting 
 there can be no progress were eliminated during three 
 centuries at the rate of a thousand a year. The evil which 
 the Catholic Church has thus effected is incalculable, 
 though no doubt counterbalanced to a certain, perhaps to 
 a large, extent in other ways; nevertheless, Europe has 
 progressed at an unparalleled rate. 
 
 The remarkable success of the English as colonists, com- 
 pared to other European nations, has been ascribed to 
 their "daring and persistent energy;" a result which is 
 well illustrated by comparing the progress of the Canadians 
 of English and French extraction; but who can say how 
 the English gained their energy ? There is apparently 
 
 *Mr. Greg, "Fraser's Magazine," Sept., 1868, p. 357. 
 
 f" Hereditary Genius," 1870, pp. 357-359. The Rev. F. W. 
 Farrar (" Fraser's Mag.," Aug. 1870, p. 257) advances arguments on 
 the other side. Sir C. Lyell had already (" Principles of Geology," 
 vol. ii, 1868, p. 489) in a striking passage called attention to the evil 
 influence of the Holy Inquisition in having, through selection, 
 lowered the general standard of intelligence in Europe.
 
 CIVILIZED NATIONS. 161 
 
 much truth in the belief that the wonderful progress 
 of the United States, as well as the character of the 
 people, are the results of natural selection; for the more 
 energetic, restless, and courageous men from all parts of 
 Europe have emigrated during the last ten or twelve 
 generations to that great country, and have there succeeded 
 best.* Looking to the distant future, I do not think that 
 the Rev. Mr. Zincke takes an exaggerated view when he 
 says : f "All other series of events as that which 
 resulted in the culture of mind in Greece, and that which 
 resulted in the empire of Rome only appear to have pur- 
 pose and value when viewed in connection with, or rather 
 as subsidiary to . . the great stream of Anglo-Saxon 
 emigration to the west." Obscure as is the problem of the 
 advance of civilization, we can at least see that a nation 
 which produced during a lengthened period the greatest 
 number of highly intellectual, energetic, brave, patriotic 
 and benevolent men, would generally prevail over less 
 favored nations. 
 
 Natural selection follows from the struggle for existence; 
 and this from a rapid rate of increase. It is impossible not 
 to regret bitterly, but whether wisely is another question, 
 the rate at which man tends to increase; for this leads in 
 barbarous tribes to infanticide and many other evils, and in 
 civilized nations to abject poverty, celibacy, and to the late 
 marriages of the prudent. But as man suffers from the 
 same physical evils as the lower animals, he has no right to 
 expect an immunity from the evils consequent on the strug- 
 gle for existence. Had he not been subjected during 
 primeval times to natural selection, assuredly he would 
 never have attained to his present rank. Since we see in 
 many parts of the world enormous areas of the most fertile 
 land capable of supporting numerous happy homes, but 
 peopled only by a few wandering savages, it might be 
 argued that the struggle for existence had not been suf- 
 ficiently severe to force man upward to his highest standard. 
 Judging from all that we know of man and the lower ani- 
 mals, there has always been sufficient variability in their 
 intellectual and moral faculties, for a steady advance 
 
 *Mr. Galton, '' Macmillan's Magazine," Aug., 1865, p. 325. See 
 also "Nature," "On Darwinism and National Life," Dec., 1869, p. 
 184. 
 
 t " Last Winter in the United States," 1868 3 p, 29.
 
 162 THE DESCENT OF MAN. 
 
 through natural selection. No doubt such advance 
 demands many favorable concurrent circumstances; but it 
 may well be doubted whether the most favorable would have 
 sufficed, had not the rate of increase been rapid, and the 
 consequent struggle for existence extremely severe. It even 
 appears from what we see, for instance, in parts of South 
 America, that a people which may be called civilized, such 
 as the Spanish settlers, is liable to become indolent and to 
 retrograde, when the conditions of life are very easy. With 
 highly civilized nations continued progress depends in a 
 subordinate degree on natural selection; for such nations 
 do not supplant and exterminate one another as do savage 
 tribes. Nevertheless the more intelligent members within 
 the same community will succeed better in the long run 
 than the inferior, and leave a more numerous progeny, and 
 this is a form of natural selection. The more efficient 
 causes of progress seem to consist of a good education 
 during youth while the brain is impressible, and of a high 
 standard of excellence, inculcated by the ablest and best 
 men, embodied in the laws, customs and traditions of the 
 nation, and enforced by public opinion. It should, however, 
 be borne in mind that the enforcement of public opinion de- 
 pends on our appreciation of the approbation and disapproba- 
 tion of others; and this appreciation is founded on our sympa- 
 thy, which it can hardly be doubted was originally developed 
 through natural selection as one of the most important 
 elements of the social instincts.* 
 
 On the Evidence That All Civilized Nations Were Once 
 Barbarous. The present subject has been treated in so full 
 and admirable a manner by Sir J. Lubbock,f Mr. Tylor, 
 Mr. M'Lennan and others, that I need here give only the 
 briefest summary of their results. The arguments recently 
 advanced by the Duke of Argyll J and formerly by Arch- 
 bishop Whately, in favor of the belief that man came into 
 the world as a civilized being, and that all savages have 
 since undergone degradation, seem to me weak in compari- 
 
 * I am much indebtecHo Mr. John Morley for some good criticisms 
 on this subject: see, also, Broca, "Les Selections," "Revue d'An- 
 thropologie," 1872. 
 
 f " On the Origin of Civilization," "Proc. Ethnological Soc.," 
 Nov 26, 1867. 
 
 J" Primeval Man," 1S69-
 
 CIVILIZED NATIONS. 163 
 
 son with those advanced on the other side. Many nations, 
 no doubt, have fallen away in civilization, and some may 
 have lapsed into utter barbarism, though on this latter head 
 I have met with no evidence. The Fuegianswere probably 
 compelled by other conquering hordes to settle in their 
 inhospitable country, and they may have become in conse- 
 quence somewhat more degraded; but it would be difficult, 
 to prove that they have fallen much below the Botocudos, ' 
 who inhabit the finest parts of Brazil. 
 
 The evidence that all civilized nations are the descend 
 ants of barbarians, consists, on the one side, of clear traces 
 of their former low condition in still-existing customs, 
 beliefs, language, etc.; and on the other side, of proofs 
 that savages are independently able to raise themselves a 
 few steps in the scale of civilization^ and have actually thus 
 risen. The evidence on the first head is extremely curious, 
 but cannot be here given, I refer to such cases as that of 
 the art of enumeration, which, as Mr. Tylor clearly shows 
 by reference to the words still used in some places, origi- 
 nated in counting the fingers, first of one hand and then of 
 the other, and lastly of the toes. We have traces of this 
 in our own decimal system, and in the Koman numerals, 
 where, after the V, which is supposed to be an abbreviated 
 picture of a human hand, we pass on to VI, etc., when 
 the other hand no doubt was used. So again, " when we 
 speak of three-score and ten, we are counting by the vigesi- 
 mal system, each score thus ideally made standing for 20 
 for 'one man 'as a Mexican or Carib would put it."* 
 According to a large and increasing school of philologists, 
 every language bears the marks of its slow and gradual evo- 
 lution. So it is with the art of writing, for letters are 
 rudiments of pictorial representations. It is hardly possi- 
 ble to read Mr. M'Lennan's work f and not admit that 
 almost all civilized nations still retain traces of such rude 
 habits as the forcible capture of wives. What ancient 
 
 *" Royal Institution of Great Britain," March 15, 1867. Also 
 " Researches Into the Early History of Mankind," 1865. 
 
 f " Primitive Marriage," 1865. See, likewise, an excellent article, 
 evidently by the same author, in the " North British Review," July, 
 1869. Also, Mr. L. H. Morgan, "A Conjectural Solution of the 
 Origin of the Class System of Relationship," in " Proc. American 
 Acad. of Sciences," vol vii, Feb., 1868. Prof, Schaaffhausen 
 (" Anthropolog. Review," Oct., 1869, p. 373) remarks on " the vestiges 
 of human sacrifices found both in Homer and the Old Testament."
 
 164 THE DESCENT OF MAN. 
 
 nation, as the same author asks, can be named that was 
 originally monogamous? The primitive idea of justice, as 
 shown by the law of battle and other customs of which ves- 
 tiges still remain, was likewise most rude. Many existing 
 superstitions are the remnants of former false religious 
 beliefs. The highest form of religion the grand idea of 
 God hating sin and loving righteousness was unknown 
 during primeval times. 
 
 Turning to the other kind of evidence: Sir J. Lubbock 
 has shown that some savages have recently improved a little 
 in some of their simpler arts. From the extremely curious 
 account which he gives of the weapons, tools and arts in 
 use among savages in various parts of the world it cannot 
 be doubted that these have nearly all been independent dis- 
 coveries, excepting perhaps the art of making fire.* The 
 Australian boomerang is a good instance of one such inde- 
 pendent discovery. The Tahitians when first visited had 
 advanced in many respects beyond the inhabitants of most 
 of the other Polynesian islands. There are no just grounds 
 for the belief that the high culture of the native Peruvians 
 and Mexicans was derived from abroad ;f many native 
 plants were there cultivated and a few native animals 
 domesticated. We should bear in mind that, judging from 
 the small influence of most missionaries, a wandering crew 
 from some semi-civilized land, if washed to the shores of 
 America, would not have produced any marked effect on 
 the natives unless they had already become somewhat ad- 
 vanced. Looking to a very remote period in the history of 
 the world we find, to use Sir J. Lubbock's well-known 
 terms, a paleolithic and neolithic period; and no one will 
 pretend that the art of grinding rough flint tools was a 
 borrowed one. In all parts of Europe, as far east as 
 Greece, in Palestine, India, Japan, New Zealand, and 
 Africa, including Egypt, flint tools have been discovered 
 in abundance; and of their use the existing inhabitants 
 retain no tradition. There is also indirect evidence of 
 their former use by the Chinese and ancient Jews. Hence 
 there can hardly be a doubt that the inhabitants of these 
 
 *Sir J. Lubbock, "Prehistoric Times," 3d edit., 1869, chap, xv 
 and xvi, et passim. See also the excellent ninth chapter in Tylor's 
 "Early History of Mankind," 3d edit., 1870. 
 
 f Dr. F. Muller has made some good remarks to this effect in th& 
 "Reise der Novara: Anthropolog. Theil," Abtheil. iii, 1868, s. 127-
 
 CIVILIZED NATIONS. 165 
 
 countries, which include nearly the whole civilized world, 
 were once in a barbarous condition. To believe that man 
 was aboriginally civilized and then suffered utter degrada- 
 tion in so many regions is to take a pitiably low view of 
 human nature. It is apparently a truer and more cheerful 
 view tliat progress has been much more general than retro- 
 gression; that man has risen, though by. slow and inter- 
 rupted steps, from a lowly condition to the highest standard 
 as yet attained by him in knowledge, morals and religion.
 
 166 THE DESCENT OF MAN. 
 
 CHAPTER VI. 
 
 ON THE AFFINITIES AND GENEALOGY OF MAN. 
 
 Position of man in the animal series The natural system genea- 
 logicalAdaptive characters of slight value Various small 
 points of resemblance between man and the Quadrumana Rank 
 of man in the natural system Birthplace and antiquity of man- 
 Absence of fossil connecting links Lower stages in the geneal- 
 ogy of man, as inferred, firstly from his affinities and secondly 
 from his structure Early androgynous condition of the verte- 
 brata Conclusion. 
 
 EVEN if it be granted that the difference between man 
 and his nearest allies is as great in corporeal structure as 
 some naturalists maintain, and although we must grant that 
 the difference between them is immense in mental power, 
 yet the facts given in the earlier chapters appear to declare, 
 in the plainest manner, that man is descended from some 
 lower form, notwithstanding that connecting-links have not 
 hitherto been discovered. 
 
 Man is liable to numerous, slight and diversified varia- 
 tions, which are induced by the same general causes, are 
 governed and transmitted in accordance with the same gen- 
 eral laws as in the lower animals. Man has multiplied so 
 rapidly that he has necessarily been exposed to struggle for 
 existence, and consequently to natural selection. He has 
 given rise to many races, some of which differ so much from 
 each other, that they have often been ranked by naturalists 
 as distinct species. His body is constructed on the same 
 homological plan as that of other mammals. He passes 
 through the same phases of embryological development. 
 He retains many rudimentary and useless structures, which 
 no doubt were once serviceable. Characters occasionally 
 make their reappearance in him, which we have reason to 
 believe were possessed by his early progenitors. If the 
 origin of man had been wholly different from that of all 
 other animals, these various appearances would be mere 
 empty deceptions ; but such an admission is incredible. 
 These appearances, on the other hand, are intelligible, at
 
 AFFINITIES AND GENEALOQ Y. 167 
 
 least to a large extent, if man is the co-descendant with 
 other mammals of some unknown and lower form. 
 
 Some naturalists, from being deeply impressed with the 
 mental and spiritual powers of man, have divided the whole 
 organic world into three kingdoms, the Human, the Animal, 
 and the Vegetable, thus giving to man a separate kingdom.* 
 Spiritual powers cannot be compared or classed by the nat- 
 ^ralist; but he may endeavor to show, as I have done, that 
 the mental faculties of man and the lower animals do not 
 differ in kind, although immensely in degree. A difference 
 in degree, however great, does not justify us in placing man 
 in a distinct kingdom, as will perhaps be best illustrated 
 by comparing the mental powers of two insects, namely, 
 a coccus or scale-insect and an ant, which undoubtedly be- 
 long to the same class. The difference is here greater than, 
 though of a somewhat different kind from, that between 
 man and. the highest mammal. The female coccus, while 
 young, attaches itself by its proboscis to a plant; sucks the 
 sap, but never moves again; is fertilized and lays eggs; and 
 this is its whole history. On the other hand, to describe 
 the habits and mental powers of worker - ants, would 
 require, as Pierre Huber has shown, a large volume; I may, 
 however, briefly specify a few points. Ants certainly com- 
 municate information to each other, and several unite for 
 the same work, or for games of play. They recognize their 
 fellow-ants after months of absence, and feel sympathy for 
 each other. They build great edifices, keep them clean, 
 close the doors in the evening, and post sentries. They 
 make roads as well as tunnels under rivers, and temporary 
 bridges over them, by clinging together. They collect food 
 for the community, and when an object, too large for 
 entrance, is brought to the nest, they enlarge the door, and 
 afterward build it up again. They store up seeds, of which 
 they prevent the germination, and which, if damp, are 
 brought up to the surface to dry. They keep aphides and 
 other insects as milch-cows. They go out to battle in regu - 
 lar bands, and freely sacrifice their lives for the common 
 weal. They emigrate according to a preconcerted plan. 
 They capture slaves. They move the eggs of their aphides, 
 as well as their own eggs and cocoons, into warm parts of 
 
 * Isidore Geoffrey St.-Hilaire gives a detailed account of the posi- 
 tion assigned to man by various naturalists in their classifications: 
 " Hist. Nat. Geii.," torn, ii, 1859, pp. 170-189.
 
 168 - TEE DESCENT OF MAN. 
 
 the nest, in order that they may be quickly hatched; and 
 endless similar facts could be given.* On the whole, the 
 difference in mental power between an ant and a coccus is 
 immense; yet no one has ever dreamed of placing these 
 insects in distinct classes, much less in distinct kingdoms. 
 No doubt the difference is bridged over by other insects; 
 and this is not the case with man and the higher apes. But 
 we have every reason to believe that the breaks in the series 
 are simply the results of many forms having become 
 extinct. 
 
 Prof. Owen, relying chiefly on the structure of the brain, 
 has divided the mammalian series into four sub-classes. 
 One of these he devotes to man; in another he places both 
 the Marsupials and the Monotremata; so that he makes 
 man as distinct from all other mammals as are these two 
 latter groups conjoined. This view has not been accepted, 
 as far as I am aware, by any naturalist capable of. forming 
 an independent judgment, and therefore need not here be 
 further considered. 
 
 We can understand why a classification founded on any 
 single character or organ even an organ so wonderfully 
 complex and important as the brain or on the high devel- 
 opment of the mental faculties, is almost sure to prove 
 unsatisfactory. This principle has indeed been tried with 
 hymenopterous insects; but when thus classed by their 
 habits or instincts, the arrangement proved thoroughly arti- 
 ficial, f Classifications may, of course, be based on any 
 character whatever, as on size, color, or the element inhab- 
 ited; but naturalists have long felt a profound conviction 
 that there is a natural system. This system, it is now generally 
 admitted, must be, as far as possible, genealogical in arrange- 
 ment that is, the co-descendants of the same form must be 
 kept together in one group, apart from the co-descendants 
 of any other form; but if the parent-forms are related, so 
 will be their descendants, and the two groups together will 
 form a larger group. The amount of difference between 
 the several groups that is, the amount of modification 
 
 * Some of the most interesting facts ever published on the habits 
 of ants are given by Mr. Belt, in his " Naturalist in Nicaragua," 
 1874. See also Mr. Moggridge's admirable work, " Harvesting 
 Ants," etc., 1873, also " L'Instinct chez les Insectes," by M. George 
 Pouchet, "Kevue des Deux Mondes," Feb. 1870, p. 682. 
 
 f WeBtwood^ " Modern Class of Insects." vol. ii. 140, p. 87.
 
 AFFINITIES AND GENEALOGY. 169 
 
 which each has undergone is expressed by such terms as 
 genera, families, orders and classes. As we have no record 
 of the lines of descent, the pedigree can be discovered only 
 by observing the degrees of resemblance between the beings 
 which are to be classed. For this object numerous points 
 of resemblance are of much more importance than the 
 amount of similarity or dissimilarity in a few points. If 
 two languages were found to resemble each other in a multi- 
 tude of words and points of construction, they would be 
 universally recognized as having sprung fr,om a common 
 source, notwithstanding that they differed greatly in some 
 few v/ords or points of construction. But with organic 
 beings the points of resemblance must not consist of adapta- 
 tions to similar habits of life; two animals may, for instance, 
 have had their whole frames modified for living in the 
 water, and yet they will not be brought any nearer to each 
 other in the natural system. Hence we can see how it is 
 that resemblances in several unimportant structures, in use- 
 less and rudimentary organs, or not now functionally active, 
 or in an embryological condition, are by far the most serv- 
 iceable for classification ; for they can hardly be due to 
 adaptations within a late period; and thus they reveal the 
 old lines of descent or of true affinity. 
 
 We can further see why a great amount of modification 
 in some one character ought not to lead us to separate 
 widely any two organisms. A part which already differs 
 much from the same part in other allied forms has already, 
 according to the theory of evolution, varied much; conse- 
 quently it would (as long as the organism remained exposed 
 to the same exciting conditions) be liable to further varia- 
 tions of the same kind; and these, if beneficial, would be 
 preserved, and thus be continually augmented. In many 
 cases the continued development of a part, for instance, of 
 the beak of a bird, or of the teeth of a mammal, would not 
 aid the species in gaining its food, or for any other object; 
 but with man we can see no definite limit to the continued 
 development of the brain and mental faculties, as far as 
 advantage is concerned. Therefore in determining the 
 position of man in the natural or genealogical system the 
 extreme development of his brain ought not to out- 
 weigh a multitude of resemblances in other less important 
 or quite 'unimportant points. 
 
 The greater number of naturalists who have taken into
 
 170 THE DESCENT OF MAN. 
 
 consideration the whole structure of man, including his 
 mental faculties, have followed Blumenbach and Ctovier, 
 and have placed man in a separate order, under the title of 
 the Bimana, and therefore on an equality with the orders of 
 the Quadrumana, Carnivora, etc. Eecently many of our 
 best naturalists have recurred to the view first propounded 
 by Linnaeus, so remarkable for his sagacity, and have placed 
 man in the same order with the Quadrumana, under the 
 title of the Primates. The justice of this conclusion will 
 "be admitted; for in the first place, we must bear in mind 
 the comparative insignificance for classification of the great 
 development of the brain in man, and that the strongly- 
 marked differences between the skulls of man and the 
 Quadrumana (lately insisted upon by Bischoff, Aeby and 
 others) apparently follow from their differently developed 
 brains. In the second place, we must remember that 
 nearly all the other and more important differences between 
 man and the Quadrumana are manifestly adaptive in their 
 nature, and relate chiefly to the erect position of man; such 
 as the structure of his hand, foot and pelvis, the curvature 
 of his spine, and the position of his head. The family of 
 seals offers a good illustration of the small importance of 
 adaptive characters for classification. These animals differ 
 from all other Carnivora in the form of their bodies and in 
 the structure of their limbs, far more than does man from 
 the higher apes; yet in most systems, from that of Cuvier 
 to the most recent one by Mr. Flower,* seals are ranked 
 as a mere family in the order of the Carnivora. If man 
 had not been his own classifier he woiild never have thought 
 of founding a separate order for his own reception. 
 
 It would be beyond my limits and quite beyond my 
 knowledge even to name the innumerable points of struct- 
 ure in which man agrees with the other Primates. Our 
 great anatomist and philosopher, Prof. Huxley, has fully 
 discussed this subject,} and concludes that man in all parts 
 of his organization differs less from the higher apes than 
 these do from the lower members of the same group. Con- 
 sequently there " is no justification for placing man in a 
 distinct order." 
 
 In an early part of this work I brought forward various 
 facts, showing how closely man agrees in constitution with 
 
 * " Proc. Zoolog. Soc.," 1863, p. 4. 
 
 \ " Evidence as to Man's Place in Nature," 1863, p. 70, et passim.
 
 AFFINITIES AND GENEALOGY. ift 
 
 the higher mammals; and this agreement must depend on 
 our close similarity in minute structure and chemical com- 
 position. I gave, as instances, our liability to the same dis- 
 eases and to the attacks of allied parasites; our tastes in 
 common for the same stimulants, and the similar effects 
 produced by them, as well as by various drugs, and other 
 such facts. 
 
 As small, unimportant points of resemblance between 
 man and the Quadrumana are not commonly noticed in 
 systematic works, and as, when numerous, they clearly 
 reveal our relationship, I will specify a few such points. 
 The relative position of our features is manifestly the same; 
 and the various emotions are displayed by nearly similar 
 movements of the muscles and skin, chiefly above the eye- 
 brows and round the mouth. Some few expressions are, 
 indeed, almost the same, as in the weeping of certain kinds 
 of monkeys and in the laughing noise made by others, 
 during which the corners of the mouth are drawn back- 
 ward and the lower eye-lids wrinkled. The external ears 
 are curiously alike. In man the nose is much more prom- 
 inent than in most monkeys; but we may trace the com- 
 mencement of an aquiline curvature in the nose of the 
 Hoolock Gibbon; and this in the Semnopithecus nasica is 
 carried to a ridiculous extreme. 
 
 The faces of many monkeys are ornamented with beards, 
 whiskers, or mustaches. The hair on the head grows to 
 a great length in some species of Semnopithecus ; * and 
 in the Bonnet monkey (Macacus radiatus) it radiates from 
 a point on the crown, with a parting down the middle. It 
 is commonly said that the forehead gives to man his noble 
 and intellectual appearance; but the thick hair on the head 
 of the Bonnet monkey terminates downward abruptly, and 
 is succeeded by hair so short and fine that at a little dis- 
 tance the forehead, with the exception of the eyebrows, 
 appears quite naked. It has been erroneously asserted that 
 eyebrows are not present in any monkey. In the species 
 just named the degree of nakedness of the forehead differs in 
 different individuals; and Eschrichtf states that in our chil- 
 dren the limit between the hairy scalp and the naked fore- 
 head is sometimes not well denned; so that here we seem 
 ' *IsiJ: Geoffrey, "Hist. Nat. Gen.," torn, ii, 1859, p. 217. 
 
 f'Ueber die Richtung der Haare," etc, Miiller's "Archiv. fiir 
 und Pliys.," 1837.
 
 173 THE DESGENT OF MAN. 
 
 to have a trifling case of reversion to a progenitor in whom 
 the forehead had not as yet become quite naked. 
 
 It is well known that the hair on our arms tends to con- 
 verge from above and below to a point at the elbow. This 
 curious arrangement, so unlike that in most of the lower 
 mammals, is common to the gorrilla, chimpanzee, orang, 
 some species of Hylobates, and even to some few American 
 monkeys. But in Hylobates agilis the hair on the forearm 
 is directed downward or toward the wrist in the ordinary 
 manner; and in H. lar it is nearly erect, with only a very 
 slight forward inclination; so that in this latter species it 
 is in a transitional state. It can hardly be doubted that 
 with most mammals the thickness of the hair on the back 
 and its direction is adapted to throw off the rain; even the 
 transverse hairs on the fore legs of a dog may serve for this 
 end when he is coiled up asleep. Mr. Wallace, who has 
 carefully studed the habits of the oraug, remarks that the 
 convergence of the hair toward the elbow on the arms of 
 the orang may be explained as serving to throw off the 
 rain, for this animal during rainy weather sits with its 
 arms bent and with the hands clasped round a branch or 
 over its head. According to Livingstone, the gorilla also 
 "sits in pelting rain with his hands over his head. "* If 
 the above explanation is correct, as seems probable, the 
 direction of the hair on our own arms offers a curious 
 record of our former state; for no one supposes that it is 
 now of any use in throwing off the rain; nor in our present 
 erect condition is it properly directed for this purpose. 
 
 It would, however, be rash to trust too much to the 
 principle of adaptation in regard to the direction of the 
 hair in man or his early progenitors; for it is impossible to 
 study the figures given by Eschricht of the arrangement of 
 the hair on the human foatus (this being the same as in the 
 adult) and not agree with this excellent observer that other 
 and more complex causes have intervened. The points of 
 convergence seem to stand in some relation to those points 
 in the embryo which are last closed in during development. 
 There appears, also, to exist some relation between the 
 arrangement of the hair on the limbs and the course of the 
 medullary arteries, f 
 
 * Quoted by Reade, " The African Sketch Book," vol. i, 1873, p. 
 152. 
 j- On the hair in Hylobates, see " Nut IIigt. of Mammals," by C. L.
 
 AFFINITIES AND GENEALOGY. 173 
 
 It must not be supposed that the resemblances between 
 man and certain apes in the above and in many other 
 points such as in having a naked forehead, long tresses on 
 the head, etc. are all necessarily the result of unbroken 
 inheritance from a common progenitor, or of subsequent 
 reversion. Many of these resemblances are more probably 
 due to analogous variation, which follows, as I have else- 
 where attempted to show,* from co-descended organisms 
 having a similar constitution, and having been acted on by 
 like causes inducing similar modifications. With respect 
 to the similar direction of the hair on the forearms of man 
 and certain monkeys, as this character is common to almost 
 all the anthropomorphous apes, it may probably be attribu- 
 ted to inheritance; but this is not certain, as some very 
 distinct American monkeys are thus characterized. 
 
 Although, as we have now seen, man has no just right to 
 form a separate Order for his own reception, he may per- 
 haps claim a distinct sub-or4er or family. Prof. Huxley, 
 in his last work,f divides the Primates into three sub- 
 orders; namely, the Anthropidse with man alone, the Simi- 
 adse, including monkeys of all kinds, and the Lemuridae 
 with the diversified genera of lemurs. As far as differ- 
 ences in certain important points of structure are concerned, 
 man may no doubt rightly claim the rank of a sub-order; 
 and this rank is too low, if we look chiefly to his mental 
 faculties. Nevertheless, from a genealogical point of view 
 it appears that this rank is too high, and that man ought 
 to form merely a family, or possibly even only a sub- 
 family. If we imagine three lines of descent proceeding 
 from a common stock, it is quite conceivable that two of 
 them might after the lapse of ages be so slightly changed 
 as still to remain a species of the same genus, while the 
 third line might become so greatly modified as to deserve 
 to rank as a distinct sub-family, family, or even order. 
 But in this case it is almost certain that the third line 
 
 Martin, 1841, p. 415. Also, Isid. Geoffrey on the American monkeys 
 and other kinds, " Hist. Nat. Gen.," vol. ii, 1859, pp. 216, 243, 
 Eschricht, ibid, ss. 46, 55, 61. Owen, "Anat. of Vertebrates," vol. 
 iii, p. 619. Wallace, " Contributions to the Theory of Natural Selec- 
 tion," 1870, p. 344. 
 
 * " Origin of Species," 5th edit., 1869, p. 194. " The Variation of 
 Animals and Plants under Domestication," vol. ii, 1868, p. 348. 
 
 f"An Introduction to the Classification of Animals," 1869, p. 99.
 
 174 THE DESCENT OF MAN. 
 
 would still retain through inheritance numerous small 
 points of resemblence with the other two. Here, then, 
 would occur the difficulty, at present insoluble, how much 
 weight we ought to assign in our classifications to strongly- 
 marked differences in some few points that is, to the 
 amount of modification undergone, and how much to close 
 resemblance in numerous unimportant points, as indicating 
 the lines of descent or genealogy. To attach much weight 
 to the few but strong differences is the most obvious and 
 peihaps the safest course, though it appears more correct 
 to pay great attention to the many small resemblances, as 
 giving a truly natural classification. 
 
 In forming a judgment on this head with reference to 
 man, we must glance at the classification of the Simiadae. 
 This family is divided by almost all naturalists into the 
 Catarrhine group, or Old "World monkeys, all of which are 
 characterized (as their name expresses) by the peculiar 
 structure of their nostrils, and by having four premolars in 
 each jaw; and into the Platyrrhine group or New World 
 monkeys (including- two very distinct sub-groups), all of 
 which are characterized by differently constructed nostrils 
 and by having six premolars in each jaw. Some other 
 small differences might be mentioned. Now man un- 
 questionably belongs in his dentition, in the structure 
 of his nostrils, and some other respects, to the Catarrhine or 
 Old World division; nor does he resemble the Platyrrhmes 
 more closely than the Catarrhines in any characters, except- 
 ing in a few of not much importance and apparently of an 
 adaptive nature. It is therefore against all probability that 
 some New World species should have formerly varied and 
 produced a man-like creature, with all the distinctive char- 
 acters proper to the Old World division; losing at the same 
 time all its own distinctive characters. There can, conse- 
 quently, hardly be a doubt that man is an off-shoot from 
 the Old World Simian stem; and that under a genealogical 
 point of view he must be classed with the Catarrhine 
 division.* 
 
 *This is nearly the same classification as that provisionally 
 adopted by Mr. St. George Mivart ("Transact. Philosoph. Soc,,* 
 1867, p. 300), who, after separating the Leinuridse, divides the 
 remainder of the Primates into the Hominidae, the Simiadae which 
 answer to the Catarrhines, the Cebidse, and the Hapalidaa these two 
 latter groups answering to the Platyrrhines. Mr. Mivart still abides 
 by the same view; see " Nature," 1871, p. 481.
 
 AFFINITIES AND GENEALOGY. 175 
 
 The anthropomorphous apes, namely, the gorilla, chim- 
 panzee, orang, and hylobates, are by most naturalists sepa- 
 rated from the other Old World monkeys, as a distinct 
 sub-group. I am aware that Gratiolet, relying on the 
 structure of the brain, does not admit the existence of this 
 sub-group, and no doubt it is a broken one. Thus the 
 orang, as Mr. St. G. Mivart remarks,* " is one of the most 
 peculiar and aberrant forms to be found in the order." The 
 remaining non-anthropomorphous Old World monkeys are 
 again divided by some naturalists into two or three smaller 
 sub-groups ; the genus Semnopithecus, with its peculiar 
 sacculated stomach, being the type of one such sub-group. 
 But it appears from M. Gaudry's wonderful discoveries in 
 Attica that during the Miocene period a form existed there 
 which connected Semnopithecus and Macacus ; and this 
 probably illustrates the manner in which the other and 
 higher groups were once blended together. 
 
 If the anthropomorphous apes he admitted to form a 
 natural sub-group, then as man agrees with them not only 
 in all those characters which he possesses in common with 
 the whole Catarrhine group, but in other peculiar characters, 
 such as the absence of a tail and of callosities, and in gen- 
 eral appearance, we may infer that some ancient member of 
 the anthropomorphous sub-group gave birth to man. It is 
 not probable that, through the law of analogous variation, 
 a member of one of the other lower sub-groups should have 
 given rise to a man-like creature resembling the higher 
 anthropomorphous apes in so many respects. No doubt 
 man, in comparison with most of his allies, has undergone 
 an extraordinary amount of modification, chiefly in conse- 
 quence of the great development of his brain and his erect 
 position; nevertheless, we should bear in mind that he " is 
 but one of several exceptional forms of Primates." f 
 
 Every naturalist who believes in the principle of evolu- 
 tion will grant that the two main divisions of the Simiada?, 
 namely, the Catarrhine and Platyrrhine monkeys, with their 
 sub-groups, have all proceeded from some one extremely 
 ancient progenitor. The early descendants of this progen- 
 itor, before they had diverged to any considerable extent 
 from each other, would still have formed a single natural 
 
 *" Transact. Zoolog. Soc.," vol. vi, 1867, p. 214. 
 
 \ Mr. St. G. Mivart, "Transact. PM1. Soc.," 1867, p. 410.
 
 ] 76 THE DESCENT OF MAN. 
 
 group; but some of the species or incipient genera would 
 nave already begun to indicate by their diverging characters 
 the future distinctive marks of the Catarrhine and 
 Platyrrhine divisions. Hence the members of this supposed 
 ancient group would not have been so uniform in their 
 dentition, or in the structure of their nostrils, as are the 
 existing Catarrhine monkeys in oneway and the Platyrrhines 
 in another way, but would have resembled in this respect 
 the allied Lemuridas, which differ greatly from each other 
 in the form of their muzzles,* and to an extraordinary 
 degree in their dentition. 
 
 The Catarrhine and Platyrrhine monkeys agree in a.multi- 
 tude of characters, as is shown by their unquestionably 
 belonging to one and the same order. The many charac- 
 ters which they possess in common can hardly have been 
 independently acquired by so many distinct species; so that 
 these characters must have been inherited. But a naturalist 
 would undoubtedly have ranked as an ape or a monkey, an 
 ancient form which possessed many characters common to 
 the Catarrhine and Platyrrhine monkeys, other characters in 
 an intermediate condition, and some few, perhaps, distinct 
 from those now found in either group. And as man from 
 a genealogical point of view belongs to the Catarrhine or Old 
 World stock, we must conclude, however much the conclu- 
 sion may revolt our pride, that our early progenitors would 
 have been properly thus designated.! But we must not 
 fall into the error of supposing that the early progenitor of 
 the whole Simian stock, including man, was identical 
 with, or even closely resembled, any existing ape or monkey. 
 
 On the Birthplace and Antiquity of Man. We are 
 naturally led to inquire, where was the birthplace of man 
 at that stage of descent when our progenitors diverged from 
 the Catarrhine stock? The fact that they belonged to this 
 stock clearly shows that they inhabitated the Old World; 
 but not Australia nor any oceanic island, as we may infer 
 
 * Messrs. Murie and Mivart on the Lemuroidea, "Transact. Zoolog. 
 Soc.," vol. vii, 1869, p. 5. 
 
 fHfickel has come to this same conclusion. See " Deber die 
 Entstehung des Menschengeschlechts," in Virchow's " Sammlung. 
 geniein, wissen. Vortrage," 1868, s. 61. Also his "Natarliche Schop 
 fungsgeschichte," 1868, in which he gives in detail his views on the 
 genealogy of man.
 
 AFFINITIES AND GENEALOG Y. 177 
 
 from the laws of geographical distribution. In each great 
 region of the world the living mammals are closely related 
 to the extinct species of the same region. It is, therefore, 
 probable that Africa was formerly inhabited by extinct apes 
 closely allied to the gorilla and chimpanzee; and as these 
 two species are now man's nearest allies, it is somewhat 
 more probable that our early progenitors lived on the 
 African continent than elsewhere. But it is useless to 
 speculate on this subject; for two or three anthropomor- 
 phous apes, one the Pryopithecus * of Lartet, nearly as 
 large as a man, and closely allied to Hylobates, existed in 
 Europe during the Miocene age; and since so remote a 
 period the earth has certainly undergone many great revo- 
 lutions, and there has been ample time for migration on the 
 largest scale. 
 
 At the period and place, whenever and wherever it was, 
 when man first lost his hairy covering, he probably 
 inhabited a hot country; a circumstance favorable for 
 the frugiferous diet on which, judging from analogy, 
 he subsisted. "We are far from knowing how long ago 
 it was when man first diverged from the Catarrhine stock; 
 but it may have occurred at an epoch as remote as the 
 Eocene period; for that the higher apes had diverged from 
 the lower apes as early as the Upper Miocene period is 
 shown by the existence of the Dryopithecus. We are also 
 quite ignorant at how rapid a rate organisms, whether high 
 or low in the scale, may be modified under favorable cir- 
 cumstances; we know, however, that some have retained 
 the same form during an enormous lapse of time. From 
 what we see going on under domestication we learn that 
 some of the co-descendants of the same species may be not 
 at all, some a little, and some greatly changed, all within 
 the same period. Thus it may have been with man, who 
 has undergone a great amount of modification in certain 
 characters in comparison with the higher apes. 
 
 The great break in the organic chain between man and 
 his nearest allies, which cannot be bridged over by any ex- 
 tinct or living species, has often been advanced as a grave 
 objection to the belief that man is descended from some 
 lower form; but this objection will not appear of much 
 
 *Dr. C. Forsytli Major, " Sur les Singes Fossiles trouves en 
 ttalie: " Soc. Ital. des Sc. Nat.," torn, xv, 172,
 
 1 78 THE D&SCENT OF MAN. 
 
 weight to those who, from general reasons, believe in the 
 general principle of evolution. Breaks often occur in all 
 parts of the series, some being wide, sharp and denned, 
 others less so in various degrees; as between the orang and 
 its nearest allies between the Tarsius and the other 
 Lemuridae between the elephant, and in a more striking 
 manner between the Ornithorhynchus or Echidna, and all 
 other mammals. But these breaks depend merely on the 
 number of related forms which have become extinct. At 
 some future period, not very distant as measured by cent- 
 uries, the civilized races of man will almost certainly ex- 
 terminate and replace the savage races throughout the 
 world. At the same time the anthropomorphous apes, as 
 Prof. Schaaffhausen has remarked,* will no doubt be ex- 
 terminated. The break between man and his nearest allies 
 will then be wider, for it will intervene between man in a 
 more civilized state, as we may hope, even than the Cauca- 
 sian, and some ape as low as a baboon, instead of as now 
 between the negro or Australian and the gorilla. 
 
 With respect to the absence of fossil remains serving to 
 connect man with his ape-like progenitors, no one will lay 
 much stress on this fact who reads Sir 0. Lyell's discus- 
 sion, f where he shows that in all the vertebrate classes the 
 discovery of fossil remains has been a very slow and fortuit- 
 ous process. Nor should it be forgotten that those regions 
 which are the most likely to afford remains connecting man 
 with some extinct ape-like creature have not as yet been 
 searched by geologists. 
 
 Lower Stages in the Genealogy of Man. We have seen 
 that man appears to have diverged from the Catarrhine or 
 Old World division of the Simiadse after these had diverged 
 from the New World division. We will now endeavor to 
 follow the remote traces of his genealogy, trusting princi- 
 pally to the mutual affinities between the various classes 
 and orders, with some Blight reference to the periods, as 
 far as ascertained, of their successive appearance on the 
 earth. The Lemuridae stand below and near to the Simiadae, 
 and constitute a very distinct family of the Primates, or, 
 according to Hiickei and others, a distinct order. This 
 
 * " Anthropological Review," April, 1867, p. 286. 
 f" Elements of Geology," 1865. pp. 583-585. "Antiquity of 
 Man," 1863, p. 145.
 
 AFFINITIES AND GENEALOGY. 179 
 
 group is diversified and broken to an extraordinary degree, 
 and includes many aberrant forms. It has, therefore, proba- 
 bly suffered much extinction. Most of the remnants sur- 
 vive on islands, such as Madagascar and the Malayan Archi- 
 pelago, where they have not been exposed to so severe a 
 competition as they would have been on well-stocked con- 
 tinents. This group likewise presents many gradations, 
 leading, as Huxley remarks,* " insensibly from the crown 
 and summit of the animal creation down to creatures 
 from which there is but a step, as it seems, to the lowest, 
 smallest and the least intelligent of the placental mam- 
 malia." From these various considerations it is probable 
 that the Simiadas were originally developed from the pro- 
 genitors of the existing Lemuridae; and these in their turn 
 from forms standing very low in the mammalian series. 
 
 The Marsupials stand in many important characters 
 below the placental mammals. They appeared at an 
 earlier geological period, and their range was formerly 
 much more extensive than at present. Hence the Placen- 
 tata are generally supposed to have been derived from the 
 Implacentata or Marsupials ; not, however, from forms 
 closely resembling the existing Marsupials, but from their 
 early progenitors. The Monotremata are plainly allied to 
 the Marsupials, forming a third and still lower division in 
 the great mammalian series. They are represented at the 
 present day solely by the Ornithorhynchus and Echidna; 
 and these two forms may be safely considered as relics of a 
 much larger group, representatives of which have been pre- 
 served in Australia, through some favorable concurrence of 
 circumstances. The Monotremata are eminently interesting, 
 as leading in several important points of structure toward 
 the class of reptiles. 
 
 In attempting to trace the genealogy of the mammalia, 
 and therefore of man, lower down in the series, we become 
 involved in greater and greater obscurity; but as a most 
 capable judge, Mr. Parker, has remarked, we have good 
 reason to believe, that no true bird or reptile intervenes in 
 the direct line of descent. He who wishes to see what 
 ingenuity and knowledge can effect, may consult Prof. 
 Hackers works, f I will content myself with a few general 
 
 *" Man's Place in Nature," p. 105. 
 
 f Elaborate tables are given in his " Generelle Morphologic " (B. 
 U, s. 153 and s. 425); and with more especial rererence to man in his
 
 180 THE DO8CENT OF MAN. 
 
 remarks. Every evolutionist will admit that the five great 
 vertebrate classes, namely, mammals, birds, reptiles, amphib- 
 ians and fishes, are descended from some one prototype; for 
 they have much in common, especially during their embry- 
 onic state. As the class of fishes is the most lowly organ- 
 ized, and appeared before the others, we may conclude that 
 all the members of the vertebrate kingdom are derived 
 from some fish-like animal. The belief that animals so 
 distinct as a monkey, an elephant, a humming-bird, a 
 snake, a frog, and a fish, etc., could all have sprung from 
 the same parents, will appear monstrous to those who have 
 not attended to the recent progress of natural history. For 
 this belief implies the former existence of links binding 
 closely together all these forms, now so utterly unlike. 
 
 Nevertheless, it is certain that groups of animals have 
 existed, or do now exist, which serve to connect several of 
 the great vertebrate classes more or less closely. We have 
 seen that the Ornithorhynchus graduates toward reptiles; 
 and Prof. Huxley has discovered, and is confirmed by Mr. 
 Cope and others, that the Dinosaurians are in many impor- 
 tant characters intermediate between certain reptiles and 
 certain birds the birds referred to being the ostrich tribe 
 (itself evidently a widely-diffused remnant of a larger 
 group) and the Archeopteryx, that strange Secondary bird, 
 with a long lizard-like tail. Again, according to Prof. 
 Owen,* the Ichthyosauriaus great sea-lizards furnished 
 with paddles present many affinities with fishes, or rather 
 according to Huxley, with amphibians ; a class which, 
 including in its highest division frogs and toads, is plainly - 
 allied to the Ganoid fishes. These latter fishes swarmed 
 during the earlier geological periods, and were constructed 
 on what is called a generalized type, that is, they presented 
 diversified affinities with other groiips of organisms. The 
 Lepidosiren is also so closely allied to amphibians and 
 fishes, that naturalists long disputed in which of these two 
 classes to rank it; it, and also some few Ganoid fishes, have 
 
 " Natiirliche SchCpfungsgeschichte," 1868. Prof. Huxley, in review- 
 ing this latter work (" The Academy," 1869, p. 42) says, that he con- 
 siders the phylum or lines of descent of the vertebrata to be admir- 
 ably discussed by Hiickel, although he differs on some points. He 
 expresses, also, his high estimate of the general tenor and spirit ol 
 the whole work. 
 
 *" Paleontology, " 1860, p. 199.
 
 AFFINITIES AND GENEALOGY. 181 
 
 been preserved from utter extinction by inhabiting rivers, 
 which are harbors of refuge, and are related to the great 
 waters of the ocean in the same way that islands are to 
 continents. 
 
 Lastly, one single member of the immense and diversi- 
 fied class of fishes, namely, the lancelet or amphioxus, is so 
 different from all other fishes, that Hackel maintains that 
 it ought to form a distinct class in the vertebrate kingdom. 
 This fish is remarkable for its negative characters; it can 
 hardly be said to possess a brain, vertebral column, or heart, 
 etc. ; so that it was classed by the older naturalists among 
 the worms. Many years ago Prof. Goodsir perceived that 
 the lancelet presented some affinities with the Ascidians, 
 which are invertebrate, hermaphrodite, marine creatures 
 permanently attached to a support. They hardly appear 
 like animals and consist of a simple, tough, leathery sack, 
 with two small projecting orifices. They belong to the 
 Mulluscoida of Huxley a lower division of the great king- 
 dom of the Mollusca; but they have recently been placed 
 by some naturalists among the Vermes or worms. Their 
 larvae somewhat resemble tadpoles in shape,* and have the 
 power of swimming freely about. M. Kovalevsky f has 
 lately observed that the larvae of Ascidians are related to 
 the vertebrata, in their manner of development, in the 
 relative position of the nervous system, and in possessing a 
 structure closely like the chorda dorsalis of vertebrate ani- 
 mals ; and in this he has been since confirmed by 
 Prof. Kupffer. M. Kovalevsky writes to me from 
 Naples, that he has now carried these observations yet fur- 
 ther, and should his results be well established, the whole 
 will form a discovery of the very greatest value. Thus, if 
 we may rely on embryology, ever the safest guide in classi- 
 
 * At the Falkland Islands I had the satisfaction of seeing, in April, 
 1833, and therefore some years tjefore any other naturalist, the loco- 
 motive larvae of a compound Ascidian, closely allied to Synoicum, 
 but apparently genorically distinct from it. The tail was about five 
 times as long as the oblong head, and terminated in a very fine fila- 
 ment. It was, as sketched by me under a simple microscope, plainly 
 divided by transverse opaque partitions, which I presume represent 
 the great cells figured by Kovalevsky. At an early stage of develop- 
 ment the tail was closely coiled round the head of the larva. 
 
 4- " Memoires de 1'Acad. des Sciences de St. Petersbourg," torn, x, 
 No. 15, 1866.
 
 182 THE DESGENT OF MAN. 
 
 tication, it seems that we have at last gained a clew to the 
 source whence the vertebrata were derived.* We should 
 then be justified in believing that at an extremely remote 
 period a group of animals existed resembling in many 
 respects the larvaa of our present Ascidians, which diverged 
 into two great branches the one retrograding in develop- 
 ment and producing the present class of Ascidians, the 
 other rising to the crown and summit of the animal king- 
 dom by- giving birth to the vertebrata. 
 
 We have thus far endeavored rudely to trace the geneal- 
 ogy of the vertebrata by the aid of their mutual affinities. 
 We will now look to man as he exists; and we shall, I think, 
 be able partially to restore the structure of our early pro- 
 genitors, during successive periods, but not in due order of 
 time. This can be effected by means of the rudiments 
 which man still retains, by the characters which occasion- 
 ally make their appearance in him through reversion, and 
 by the aid of the principles of morphology and embryology. 
 The various facts, to which I shall here allude, have been 
 given in the previous chapters. 
 
 The early progenitors of man must have been once cov- 
 ered with hair, both sexes having beards; their ears were 
 probably pointed and capable of movement ; and their 
 bodies were provided with a tail, having the proper muscles. 
 Their limbs and bodies were also acted ,on b} r many mus- 
 cles which now only occasionally reappear, but are normally 
 present in the Quadrumana. At this or some earlier period 
 the great artery and nerve of the humerus ran through a 
 supracondyloid foramen. The intestine gave forth a much 
 larger diverticulum or caecum than that now existing. The 
 foot was th&a prehensile, judging from the condition of the 
 great toe in the foetus; and our progenitors, no doubt, were 
 arboreal in their habits, and frequented some warm, forest- 
 clad land. The males had great canine teeth, which served 
 
 *But I am bound to add that some competent judges dispute this 
 conclusion; for instance, M. Giard, in a series of papers in the 
 ' Archives de Zoologie Experiinentale," for 1872. Nevertheless, this 
 naturalist remarks, p. 381, Disorganization de la larve ascidienne eu 
 cidiors de toute hypothese et de toute theorie, nous inomre comment 
 la nature peut produire la disposition fondamentale du type veltebre" 
 (1'existence d \.*ve corde dorsale) chez un invertebre par la seule con- 
 dition vitale de 1'adaptation, et cette simple possibilite du passage 
 supprirue 1'abime entre les deux sous-regnes, encore bien qu'en ignow 
 par ou \e pMMga ^BB* fait en realite."
 
 AFFINITIES AND GENEALOGY. 183 
 
 them as formidable weapons. At a much earlier period the 
 uterus was double ; the excreta were voided through a 
 cloaca; and the eye was protected by a third eye-lid or nic- 
 titating membrane. At a still earlier period the progenitors 
 of man must have been aquatic in their habits; for morphology 
 
 C* aly tells us that our lungs consist of a modified swim- 
 dor, which once served as a float. The clefts on the 
 neck in the embryo of man show where the branchiaB once 
 existed. In the lunar or weekly recurrent periods of some 
 of our functions we apparently still retain traces of our 
 primordial birth-place, a shore washed by the tides. At 
 about this same early period the true kidneys were replaced 
 by the corpora wolffiana. The heart existed as a simple 
 pulsating vessel; and the chorda dorsalis took the place of 
 a vertebral column. These early ancestors of man, thus 
 seen in the dim recesses of time, must have been as simply, 
 or even still more simply, organized than the lancelet or 
 amphioxus. 
 
 There is one other point deserving a fuller notice. It, 
 has long been known that in the vertebrate kingdom one 
 sex bears rudiments of various accessory parts, appertain- 
 ing to the reproductive system, which propeily belong to 
 the opposite sex; and it has now been ascertained that at a 
 very early embryonic period both sexes possessed true male 
 and female glands. Hence some remote progenitor of the 
 whole vertebrate kingdom appears to have been hermaph- 
 rodite or androgynous.* But here we encounter a singu- 
 lar difficulty. In the mammalian class the males possess 
 rudiments of a uterus with the adjacent passage, in their 
 vesiculae prostaticag; they bear also rudiments of mammae, 
 and some male Marsupials have traces of a marsupial sack. { 
 Other analogous facts could be added. Are we, then, to 
 suppose that some extremely ancient mammal continued 
 
 *This is the conclusion of Prof. Gegenbaur, one of the highest 
 authorities in comparative anatomy; see " Grundziige der vergleich. 
 Anat.," 1870, s. 876. The result has been arrived at chiefly from the 
 study of the Amphibia; but it appears from the researches of Wald- 
 eyer (as quoted in " Journal of Anat. and Phys.," 1869, p. 161), that 
 the sexual organs of even " the higher vertebrata are in their early 
 condition hermaphrodite." Similar views have long been held by 
 some authors, though until recently without a firm basis. 
 
 | The male Thylacinus offers the best instance. Owen, " Anatomy 
 of Vertebrates," Vol. lii, p. 771.
 
 184 THE DESCENT OF MAN. 
 
 androgynous, after it had acquired the chief distinctions of 
 its class, and, therefore, after it had diverged from the 
 lower classes of the vertebrate kingdom? This seems very 
 improbable, for we have to look to fishes, the lowest of all 
 the classes, to find any still existent androgynous forms.* 
 That various accessory parts, proper to each sex, are found 
 in a rudimentary condition in the opposite sex, may be 
 explained by such organs having been gradually acquired 
 by the one sex, and then transmitted in a more or less 
 imperfect state to the other. When we treat of sexual 
 selection we shall meet with innumerable instances of this 
 form of transmission as in the case of the spurs, plumes, 
 and brilliant colors, acquired for battle or ornament by 
 male birds and inherited by the females in an imperfect or 
 rudimentary condition. 
 
 The possession by male mammals of functionally imper- 
 fect mammary organs is, in some respects, especially 
 curious. The Monotremata have the proper milk-secreting 
 glands with orifices, but no nipples; and as these animals 
 stand at the very base of the mammalian series, it is proba- 
 ble that the progenitors of the class also had milk-secreting 
 glands, but no nipples. This conclusion is supported by 
 what is known of their manner of development; for Prof. 
 Turner informs me, on the authority of Kolliker and 
 Langer, that in the embryo the mammary glands can be 
 distinctly traced before the nipples are in the least visible; 
 and the development of successive parts in the individual 
 generally represents and accords with the development of 
 successive beings in the same line of descent. The Mar- 
 supials differ from the Monotremata by possessing nipples; 
 so that probably these organs were first acquired by the 
 Marsupials, after they had diverged from, and risen above, 
 the Monotremata, and were then transmitted to the 
 
 * Hermapliroditism has been observed in several species of Ser- 
 ranus, as well as in some other fishes, where it is either normal and 
 symmetrical, or abnormal and unilateral. Dr. Zouteveen has given 
 me references on this subject, more especially to a paper by Prof. 
 Halbertsma, in the " Transact, of the Dutch Acad. of Sciences," vol. 
 xvi. Dr. Gtinther doubts the fact, but it has now been recorded by 
 too many good observers to be any longer disputed. Dr. M. Lessona 
 writes to me that he has verified the observations made by Cavolini 
 on Serranus. Prof. Ercolani has recently shown (" Accad. delle 
 Scieuze," Bologna. Dec. 28, 1871) that eels are androgynous.
 
 AFFINITIES AND GENEALOGY. 185 
 
 placenta! mammals.* No one will suppose that the Mar- 
 supials still remained androgynous after they had approx- 
 imately acquired their present structure. How then are 
 we to account for male mammals possessing mammae? It 
 is possible that they were first developed in the females and 
 then transferred to the males, but from what follows this is 
 hardly probable. 
 
 It may be suggested, as another view, that long after the 
 progenitors of the whole mammalian class had ceased to be 
 androgynous, both sexes yielded milk, and thus nourished 
 their young; and in the case of the Marsupials, that both 
 sexes carried their young marsupial sacks. This will not 
 appear altogether improbable, if we reflect that the males 
 of existing syngnathous fishes receive the eggs of the 
 females in their abdominal pouches, hatch them, and after- 
 ward, as some believe, nourish the young; f that certain 
 other male fishes hatch the eggs within their mouths or 
 branchial cavities; that certain male toads take the chaplets 
 of eggs from the females and wind them round their own 
 thighs, keeping them there until the tadpoles are born; 
 that certain male birds undertake the whole duty of incuba- 
 tion, and that male pigeons, as well as the females, feed 
 their nestlings with a secretion from their crops. But the 
 above suggestion first occurred to me from the mammary 
 glands of male mammals being so much more perfectly 
 developed than the rudiments of the other accessory repro- 
 ductive parts, which are found in the one sex though proper 
 to the other. The mammary glands and nipples, as they 
 exist in male mammals, can indeed hardly be called rudiment- 
 ary; they are merely not fully developed and not functionally 
 
 *Prof. Gegenbaur has shown (" Jenaisclie Zeitsclirift," Bd. vii, p. 
 212) that two distinct types of nipples prevail throughout the several 
 mammalian orders, but that it is quite intelligible how both could 
 have been derived from the nipples of the Marsupials, and the latter 
 from those of the Monotremata. See, also, a memoir by Dr. Max 
 Huss, on the mammary glands, ibid., B. viii, p. 176. 
 
 f Mr. Lockwood believes (as quoted in ' ' Quart. Journal of 
 Science," April, 1868, p. 269), from what he has observed of the 
 development of Hippocampus, that the walls of the abdominal 
 pouch of the male in some way afford nourishment. On male fishes 
 hatching the ova in their mouths, see a very interesting paper by 
 Prof. Wyjuan, in " Proc. Boston Soc. of Nat. Hist.," Sept. 15, 1867; 
 also Prof. Turner, in "Journal of Anat. and Phys.," Nov. 1, 1866, p. 
 78. Dr. Gunther has likewise described similar cases.
 
 186 THE DESCENT OF MAN. 
 
 active. They are sympathetically affected under the influ- 
 ence of certain diseases, like the same organs in the female. 
 They often secrete a few drops of milk at birth and at 
 puberty; this latter fact occurred in the curious case, before 
 referred to, where a young man possessed two pairs of 
 mammae. In man and some other male mammals these 
 organs have been known occasionally to become so well 
 developed during maturity as to yield a fair supply of milk. 
 Now if we suppose that during a former prolonged period 
 male mammals aided the females in nursing their off spring,* 
 and that afterward from some cause (as from the production 
 of a smaller number of young) the males ceased to give this 
 aid, disuse of the organs during maturity would lead to their 
 becoming inactive; and from two well-known principles of 
 inheritance, this state of inactivity would probably be trans- 
 mitted to the males at the corresponding age of maturity. 
 But at an earlier age these organs would be left unaffected, 
 so that they would be almost equally well developed in 
 the young of both sexes. 
 
 Conclusion. Von Baer has defined advancement or prog- 
 ress in the organic scale better than any one else as resting 
 on the amount of differentiation and specialization of the 
 several parts of a being when arrived at maturity, as I 
 should be inclined to add. Now, as organisms have become 
 slowly adapted to diversified lines of life by means of nat- 
 ural selection, their parts will have become more and more 
 differentiated and specialized for various functions from 
 the advantage gained by the division of physiological labor. 
 The same part appears often to have been modified first for 
 one purpose, and then long afterward for some other and 
 quite distinct purpose; and thus all the parts are rendered 
 more and more complex. But each organism still retains 
 the general type of structure of the progenitor from which 
 it was aboriginally derived. In accordance with this view 
 it seems, if we turn to geological evidence, that organiza- 
 tion on the whole has advanced throughout the world by 
 slow and interrupted steps. In the great kingdom of the 
 vertebrata it has culminated in man. It must not, how- 
 ever, be supposed that groups of organic beings are always 
 
 * Maddle. C. Royer has suggested a similar view in her " Origine 
 de 1'Hoiume," etc., 1870.
 
 AFFINITIES AND GENEALOGY. 187 
 
 supplanted and disappear as soon as they have given birth 
 to other and more perfect groups. The latter, though 
 victorious over their predecessors, may not have become 
 better adapted for all places in the economy of nature. 
 Some old forms appear to have survived from inhabiting 
 protected sites where they have not been exposed to very 
 severe competition; and these often aid us in constructing 
 our genealogies by giving us a fair idea of former and lost 
 populations. But we must not fall into the error of look- 
 ing at the existing members of any lowly organized group 
 as perfect representatives of their ancient predecessors. 
 
 The most ancient progenitors in the kingdom of the 
 vertebrata, at which we are able to obtain an obscure glance, 
 apparently consisted of a group of marine animals* resem- 
 bling the larvae of existing Ascidians. These animals 
 probably gave rise to a group of fishes, as lowly organized 
 as the lancelet ; and from these the Ganoids, and other 
 fishes like the Lepidosiren, must have been developed. 
 From such fish a very small advance would carry us on to 
 the Amphibians. We have seen that birds and reptiles 
 
 * The inhabitants of the seashore must be greatly affected by the 
 tides; animals living either about the mean high-water mark, or about 
 the mean low-water mark, pass through a complete cycle of tidal 
 changes in a fortnight. Consequently their food supply will undergo 
 marked changes week by week. The vital functions of such ani- 
 mals, living under these conditions for many generations, can hardly 
 fail to run their course in regular weekly periods. Now it is a mys- 
 terious fact that in the higher and now terrestrial vertebrata, as well 
 as in other classes, many normal and abnormal processes have one or 
 more whole weeks as their periods; this would be rendered intelligi- 
 ble if the vertebrata are descended from an animal allied to the 
 existing tidal Ascidians. Many instances of such periodic processes 
 might be given, as the gestation of mammals, the duration of fevers, 
 etc. The hatching of eggs affords also a good example, for, accord- 
 ing to Mr. Bartlett (" Land and Water," Jan. 7, 1871), the eggs of 
 the pigeon are hatched in two weeks; those of the fowl in three; 
 those of the duck in four; those of the goose in five; and those of the 
 ostrich in seven weeks. As far as we can judge, a recurrent period, 
 if approximately of the right duration for any process of function, 
 would not, when once gained, be liable to change; consequently it 
 might be thus transmitted through almost any number of genera- 
 tions. But if the function changed, the period would have to 
 change, and would be apt to change almost abruptly by a whole 
 week. This conclusion, if sound, is highly remarkable; for the 
 period of gestation in each mammal, and the hatching of each bird's 
 eggs, and many other vital processes, thus betray to us the primor- 
 dial birthplace of these animals.
 
 188 THE DESCENT OF MAN. 
 
 were once intimately connected together; and the Monotre* 
 mata now connect mammals with reptiles in a slight degree. 
 But no one can at present say by what line of descent the 
 three higher and related classes, namely, mammals, birds, 
 and reptiles, were derived from the two lower vertebrate 
 classes, namely, amphibians and fishes. In the class of 
 mammals the steps are not difficult to conceive which led 
 from the ancient Mouotremata to the ancient Marsupials ; 
 and from these to the early progenitors of the placenta! 
 mammals. We may thus ascend to the Lemuridse; and the 
 interval is not very wide from these to the Simiadae. The 
 Simiadae then branched off into two great stems, the New 
 World and Old World monkeys; and from the latter at a 
 remote period, Man, the wonder and glory of the universe, 
 proceeded. 
 
 Thus we have given to man a pedigree of prodigious 
 length, but not, it may be said, of noble quality. The 
 world, it has often been remarked, appears as if it had long 
 been preparing for the advent of man; and this, in one 
 sense, is strictly true, for he owes his birth to a long line of 
 progenitors. If any single link in this chain had never 
 existed, man would not have been exactly what he now is. 
 Unless we wilfully close our eyes, we may, with our pres- 
 ent knowledge, approximately recognize our parentage; nor 
 need we feel ashamed of it. 'The most humble organism is 
 something much higher than the inorganic dust under our 
 feet ; and no one with an unbiased mind can study any 
 living creature, however humble, without being struck with 
 enthusiasm at its marvelous structure and properties.
 
 THE RACES OF MAN. 189 
 
 CHAPTER VII. 
 
 ON THE RACES OF MAN. 
 
 The nature and value of specific characters Application to the 
 races of man Arguments in favor of, and opposed to, ranking 
 the so-called races of man as distinct species Sub-species 
 Monogenists and polygenists Convergence of character 
 Numerous points of resemblance in body and mind between the 
 most distinct races of man The state of man when he first 
 spread over the earth Each race not descended from a single 
 pair The extinction of races The formation of races The 
 effects of crossing Slight influence of the direct action of the 
 conditions of life Slight or no influence of natural selection 
 Sexual selection. 
 
 IT is not my intention here to describe the several so- 
 called races of men; but I am about to inquire what is the 
 value of the differences between them under a classificatory 
 point of view and how they have originated. In determin- 
 ing whether two or more allied forms ought to be ranked 
 as species or varieties, naturalists are practically guided by 
 the following considerations, namely, the amount of differ- 
 ence between them, and whether such differences relate to 
 few or many points of structure, and whether they are of 
 physiological importance; but more especially whether they 
 are constant. Constancy of character is what is chiefly 
 valued and sought for by naturalists. Whenever it can be 
 shown, or rendered probable, that the forms in question 
 have remained distinct for a long period, this becomes an 
 argument of much weight in favor of treating them as 
 species. Even a slight degree of sterility between any two 
 forms when first crossed, or in their offspring, is generally 
 considered as a decisive test of their specific distinctness; 
 and their continued persistence without blending within 
 the same area, is usually accepted as sufficient evidence, 
 either of some degree of mutual sterility, or in the case of 
 animals- of some mutual repugnance to pairing. 
 
 Independently of fusion from intercrossing, the complete 
 absence, in a well-investigated region, of varieties linking
 
 190 THE DESCENT OF MAN. 
 
 together any two closely allied forms, is probably the most 
 important of all the criterions of their specific distinctness; 
 and this is a somewhat different consideration from mere 
 constancy of character, for two forms may be highly vari- 
 able and yet not yield intermediate varieties. Geographical 
 distribution is often brought into play unconsciously and 
 sometimes consciously; so that forms living in two widely 
 separated areas, in which most of the other inhabitants are 
 specifically distinct, are themselves usually looked at as dis- 
 tinct; but in truth this affords no aid in distinguishing 
 geographical races from so-called good or true species. 
 
 Now let us apply these generally admitted principles to 
 the races of man, viewing him in the same spirit as a nat- 
 uralist would any other animal. In regard to the amount 
 of difference between the races, we must make some allow- 
 ance for our nice powers of discrimination gained by the 
 long habit of observing ourselves. In India, as Elphinstoue 
 remarks, although a newly arrived European cannot at first 
 distinguish the various native races, yet they soon appear 
 to him extremely dissimilar;* and the Hindoo cannot at 
 first perceive any difference between the several European 
 nations. Even the most distinct races of man are much 
 more like each other in form than would at first be sup- 
 posed; certain negro tribes must be excepted, while others, 
 as Dr. Kohlfs writes to me, and as I have myself seen, have 
 Caucasian features. This general similarity is well shown 
 by the French photographs in the Collection Anthropolo- 
 gique du Museum de Paris of the men belonging to various 
 races, the greater number of which might pass for Euro- 
 peans, as many persons to whom I have shown them have 
 remarked. Nevertheless, these men, if seen alive, would 
 undoubtedly appear very distinct, so that we are clearly 
 much influenced in our judgment by the mere color of the 
 skin and hair, by slight differences in the features, and by 
 expression. 
 
 There is, however, no doubt that the various races, when 
 carefully compared and measured, differ much from each 
 other as in the texture of the hair, the relative propor- 
 tions of all parts of the body,f the capacity of the 
 
 *" History of India," 1841, vol. i, p. 323. Father Ripa makes 
 exactly the same remark with respect to the Chinese. 
 
 f A vast number of measurements of Whites, Blacks and Indians 
 are given in the ' ' Investigations in the Military and Anthropolog.
 
 THE RACES OF MAN. 191 
 
 lungs, the form and capacity of the skull, and even 
 in the convolutions of the brain.* But it would be 
 an endless task to specify the numerous points of dif- 
 ference. The races differ also in constitution, in acclima- 
 tization and in liability to certain diseases. Their mental 
 characteristics are likewise very distinct; chiefly as it would 
 appear in their emotional, but partly in their intellectual 
 faculties. Every one who has had the opportunity of com- 
 parison must have been struck with the contrast between 
 the taciturn, even morose, aborigines of South America and 
 the light-hearted, talkative negroes. There is a nearly sim- 
 ilar contrast between \the Malays and the Papuans,! wno 
 live under the same physical conditions and are separated 
 from each other only by a narrow space of sea. 
 
 We will first consider the arguments which may be 
 advanced in favor of classing the races of man as distinct 
 species, and then the arguments on the other side. If a 
 naturalist, who had never before seen a Negro, Hottentot, 
 Australian or Mongolian, were to compare them, he would 
 at once perceive that they differed in a multitude of char- 
 acters, some of slight and some of considerable importance. 
 On inquiry he would find that they were adapted to live under 
 widely different climates, and that they differed somewhat in 
 bodily constitution and mental disposition. If he were 
 then told that hundreds of similar specimens could be 
 brought from the same countries, he would assuredly 
 declare that they were as good species as many to which he 
 had been in the habit of affixing specific names. This con- 
 clusion would be greatly strengthened as soon as he had 
 ascertained that these forms had all retained the same 
 character for many centuries; and that negroes, apparently 
 identical with existing negroes, had lived at least 4,000 
 years ago.J He would also hear, on the authority of an 
 
 Statistics of American Soldiers," by B. A. Gould, 1869, pp. 298-358; 
 " On the capacity of tlie lungs," p. 471. See also the numerous and 
 valuable tables, by Dr. Weisbach, from the observations of Dr. 
 Scherzer and Dr. Schwarz, in the " Reise der Novara; Anthropolog. 
 Theil," 1867. 
 
 * See, for instance, Mr. Marshall's account of the brain of a Bush- 
 woman, in "Phil. Transact.," 1864, p. 519. 
 
 fWallace, "The Malay Archipelago," vol. ii. 1869, p. 178. 
 
 \ With respect to the figures in the famous Egyptian caves of 
 Abou-Simbe'i, M. Pouchet says ("The Plurality of the Human
 
 193 THE DESCENT OF MAN. 
 
 excellent observer, Dr. Lund,* that the human skulls 
 found in the caves of Brazil, entombed with many extinct 
 mammals, belonged to the same type as that now prevail- 
 ing throughout the American Continent. 
 
 Our naturalist would then perhaps turn to geographical 
 distribution, and he would probably declare that those 
 forms must be distinct species, which differ not only in 
 appearance, but are fitted for hot, as well as damp or dry 
 countries, and for the Arctic regions. He might appeal to 
 the fact that no species in the group next to man namely, 
 the Quadrumaua, can resist a low temperature, or any con- 
 siderable change of climate; and that the species which 
 come nearest to man have never been reared to maturity, 
 even under the temperate climate of Europe. He would 
 be deeply impressed with the fact, first noticed by Agassiz,f 
 that the different races of man are distributed over the 
 world in the same zoological provinces as those inhabited 
 by undoubtedly distinct species and genera of mammals. 
 This is manifestly the case with the Australian, Mongolian, 
 and Negro races of man; in a less well-marked manner 
 with the Hottentots; but plainly with the Papuans and 
 Malays, who are separated, us Mr. Wallace has shown, by 
 nearly the same line which divides the great Malayan and 
 Australian zoological provinces. The Aborigines of America 
 
 Races," Eug. trauslat., 1864, p. 50), that he was far from finding 
 recognizable representations of the dozen or more nations which 
 some authors believe that they can recognize. Even some of the 
 most strongly-marked races cannot be identified with that degree of 
 unanimity which might have been expected from what has been 
 written on the subject. Thus Messrs. Nott and Gliddon (" Types of 
 Mankind," p. 148), state that Barneses II, or the Great, has features 
 superbly European; whereas Knox, another firm believer in the 
 specific distinctness of the races of man (" Races of Man," 1850, p. 
 201), speaking of young Memnou (the same as Rameses II, as I am 
 informed by Mr. Birch), insists in the strongest manner that he is 
 identical in character with the Jews of Antwerp. Again, when I 
 looked at the statue of Amunoph III, I agreed with two officers of 
 the establishment, both competent judges, that he had a strongly- 
 marked negro type of features; but Messrs. Nott and Gliddon (ibid, 
 p. 146, fig. 53), describe him as a hybrid, but not of "negro inter- 
 mixture." 
 
 * As quoted by Nott and Gliddon, " Types of Mankind," 1854, p. 439. 
 They give also corroborative evidence; but C. Vogt thinks that the 
 subject requires further investigation. 
 
 f " Diversity of Origin of the Human Races," in the " Christcar 
 Examiner," July, 1850.
 
 THE RACES OF MAN. 193 
 
 range throughout the Continent; and this at first appears 
 opposed to the above rule, for most of the productions .of 
 the Southern and Northern halves differ widely; yet some 
 few living forms, as the opossum, range from the one into 
 the" other, as did formerly some of the gigantic Edentata. 
 The Esquimaux, like other Arctic animals, extend round the 
 whole polar regions. It should be observed that the 
 amount of difference between the mammals of the several 
 zoological provinces does not correspond with the degree of 
 separation between the latter; so that it can hardly be con- 
 sidered as an anomaly that the Negro differs more, and the 
 American much less from the other races of man, than do 
 the mammals of the African and American Continents 
 from the mammals of the other provinces. Man, it may be 
 added, does not appear to have aboriginally inhabited any 
 oceanic island; and in this respect he resembles the other 
 members of his class. 
 
 In determining whether the supposed varieties of the 
 same kind of domestic animal should be ranked as such, or 
 as specifically distinct, that is, whether any of them are 
 descended from distinct wild species, every naturalist would 
 lay much stress on the fact of their external parasites being 
 specifically distinct. All the more stress would be laid on 
 this fact, as it would be an exceptional one; for I am in- 
 formed by Mr. Denny that the most different kinds of 
 dogs, fowls and pigeons in England are infested by the 
 same species of Pediculi or lice. Now Mr. A. Murray has 
 carefully examined the Pediculi collected in different coun- 
 tries from the different races of man;* and he finds that 
 they differ, not only in color, but in the structure of their 
 claws and limbs. In every case in which many specimens 
 were obtained the differences were constant. The surgeon 
 of a whaling ship in the Pacific assured me that when the 
 Pediculi, with which some Sandwich Islanders on board 
 swarmed, strayed on to the bodies of the English sailors 
 they died in the course of three or four days. These Pedi- 
 culi were darker colored and appeared different from those 
 proper to the natives of Chili, in South America, of which 
 he gave me specimens. These, again, appeared larger and 
 much softer than European lice. Mr. Murray procured 
 four kinc^s from Africa, namely, from the Negroes of the 
 
 * "Transact. B. Soc. of Edinburgh," vol. xxii, 1861, p. 567.
 
 194 THE DESCENT OF MAN. 
 
 Eastern and "Western coasts, from the Hottentots and 
 Kaffirs; two kinds from the natives of Australia; two from 
 North and two from South America. In these latter cases 
 it may be presumed that the Pediculi came from natives 
 inhabiting different districts. With insects slight struct- 
 ural differences, if constant, are generally esteemed of 
 specific value; and the fact of the races of man being in- 
 fested by parasites which appear to be specifically distinct 
 might fairly be urged as an argument that the races them- 
 selves ought to be classed as distinct species. 
 
 Our supposed naturalist having proceeded thus far in his 
 investigation would next inquire whether the races of men, 
 when crossed, were in any degree sterile. He might con- 
 sult the work* of Prof. Broca, a cautious and philosophical 
 observer, and in this he would find good evidence that 
 some races were quite fertile together, but evidence of an 
 opposite nature in regard to other races. Thus it has been 
 asserted that the native women of Australia and Tasmania 
 rarely produce children to European men; the evidence, 
 however, on this head has now been shown to be almost 
 valueless. The half-castes are killed by the pure blacks; 
 and an account has lately been published of eleven half- 
 caste youths murdered and burned at the same time whose 
 remains were found by the police, f Again, it has often 
 been said that when mulattoes intermarry they produce 
 few children; on the other hand, Dr. Bachman, of Charles- 
 ton, J positively asserts that he has known mulatto families 
 which have intermarried for several generations, and have 
 continued on an average as fertile as either pure whites or 
 pure blacks. Inquiries formerly made by Sir C. Lyell on 
 this subject led him, as he informs me, to the same con- 
 
 *"On the Phenomena of Hybridity in the Genus Homo," Eng. 
 translat., 1864. 
 
 f See the interesting letter by Mr. T. A. Murray, in the " Anthro- 
 polog. Review," April, 1868, p. 53. In this letter Count Strzelecki's 
 statement that Australian women who have borne children to a white 
 man are afterward sterile with their own race is disproved. M. A. 
 de Quatrefages has also collected (" Revue des Cours Scientifiques," 
 March, 1869, p. 239) much evidence that Australians and Europeans 
 are not sterile when crossed. 
 
 \ " An Examination of Prof. Agassiz's Sketch of the Nat. Provinces 
 of the Animal World," Charleston, 1855, p. 44.
 
 THE RACES OF MAN. 195 
 
 elusion.* In the United States the census for the year 
 1854 included, according to Dr. Bachman, 405, 751 mulat- 
 toes; and this number, considering all the circumstances 
 of the case, seems small; but it may partly be accounted for 
 by the degraded and anomalous position of the class and 
 by the profligacy of the women. A certain amount of 
 absorption of mulattoes into negroes must always be in 
 progress; and this would lead to an apparent diminution of 
 the former. The inferior vitality of mulattoes is spoken of 
 in a trustworthy workf as a well-known phenomenon; and 
 this, although a different consideration from their lessened 
 fertility, may perhaps be advanced as a proof of the specific 
 distinctness of the parent races. No doubt both animal 
 and vegetable hybrids, when produced from extremely dis- 
 tinct species, are liable to premature death; but the parents 
 of mulattoes cannot be put under the category of extremely 
 distinct species. The common mule, so notorious for long 
 life and vigor, and yet so sterile, shows how little necessary 
 connection there is in hybrids between lessened fertility 
 and vitality; other analogous cases could be cited. 
 
 Even if it should hereafter be proved that all the races 
 of men were perfectly fertile together, he who was inclined 
 from other reasons to rank them as distinct species, might 
 with justice argue that fertility and sterility are not safe 
 criterions of specific distinctness. We know that these 
 qualities are easily affected by changed conditions of life, 
 or by close inter-breeding, and that they are governed by 
 highly complex laws, for instance, that of the unequal fer- 
 tility of converse crosses between the same two species. 
 With forms which must be ranked as undoubted species, a 
 perfect series exists from those which are absolutely sterile 
 when crossed, to those which are almost or completely fer- 
 tile. The degrees of sterility do not coincide strictly with 
 
 * Dr. Rohlfs writes to me that lie found the mixed races in the 
 Great Sahara, derived from Arabs, Berbers, and Negroes of three 
 tribes, extraordinarily fertile. On the other hai>d, Mr. Winwood 
 Reade informs me that the Negroes on the Gold Coast, though admir- 
 ing white men and mulattoes, have a maxim that mulattoes should 
 not intermarry, as the children are few and sickly. This belief, as 
 Mr. Reade remarks, deserves attention, as white men have visited 
 and resided on the Gold Coast for four hundred years, so that the 
 natives havfs had ample time to gain knowledge through experience. 
 
 f" Military and Anthropolog. Statistics of American Soldiers," by 
 B. A. Gould, 1869, p. 319.
 
 196 THE DESCENT OF MAN. 
 
 the degrees of difference between the parents in external 
 structure or habits of life. Man in many respects may be 
 compared with those animals which have long been domes- 
 ticated, and a large body of evidence can be advanced in 
 favor of the Pallasian doctrine,* that domestication tends 
 to eliminate the sterility which is so general a result of the 
 crossing of species in a state of nature. From these sev- 
 eral considerations, it may be justly urged that the perfect 
 fertility of the intercrossed races of man, if established, 
 would not absolutely preclude us from ranking them as 
 distinct species. 
 
 Independently of fertility, the characters presented by 
 the offspring from a cross have been thought to indicate 
 whether or not the parent-forms ought to be ranked as 
 
 * " The Variation of Animals and Plants under Domestication," vol. 
 ii, p. 109. I may here remind the reader that the sterility of species 
 when crossed is not a specially acquired quality, but, like the inca- 
 pacity of certain trees to be grafted together, is incidental on other 
 acquired differences. The nature of these differences is unknown, 
 but they relate more especially to the reproductive system, and much 
 less so to external structure or to ordinary differences in constitution. 
 One important element in the sterility of crossed species apparently 
 lies in one or both having been long habituated to fixed conditions; 
 for we know that changed conditions have a special influence on the 
 reproductive system, and \ve have good reason to believe (as before 
 remarked) that the fluctuating conditions of domestication tend to 
 eliminate that sterility which is so general with species, in a natural 
 state, when crossed. It has elsewhere been shown by me (ibid., vol. 
 ii, p. 185, and " Origin of Species," 5th edit., p. 317),' that the steril- 
 ity of crossed species has not been acquired through natural selection; 
 we can see that when two forms have already been rendered very 
 sterile, it is scarcely possible that their sterility should be aug- 
 mented by the preservation or survival of the more and more sterile 
 individuals; for, as the sterility increases, fewer and fewer offspring 
 will be produced from which to breed, and at last only single indi- 
 viduals will be produced at the rarest intervals. But there is even a 
 higher grade of sterility than this. Both Gartner and K61 renter 
 have proved that in genera of plants, including many species, a series 
 can be formed from species which, when crossed, yield fewer and 
 fewer seeds, to species which never produce a single seed, but yet 
 are affected by the pollen of the other species, as shown by the 
 swelling of the germen. It is here manifestly impossible to select 
 the more sterile individuals, which have already ceased to yield 
 seeds; so that the acme of sterility, when the germen alone is 
 affected, cannot have been gained through selection. This acme, 
 and no doubt the other grades of sterility, are the incidental results 
 of certain unknown differences in the constitution of the reproductive 
 system of the species which are crossed.
 
 THE RACES OF MAN. 197 
 
 species or varieties; but after carefully studying the evi- 
 dence, I have come to the conclusion that no general rules 
 of this kind can be trusted. The ordinary result of a cross 
 is the production of a blended or intermediate form; but in 
 certain cases some of the offspring take closely after one 
 parent-form and some after the other. This is especially 
 apt to occur when the parents differ in characters which 
 first appeared as sudden variations or monstrosities.* 1. 
 refer to this point because Dr. Rohlfs informs me that he 
 has frequently seen in Africa the offspring of negroes crossed 
 with members of other races, either completely black or 
 completely white, or rarely piebald. On the other hand, it 
 is notorious that in America mulattoes commonly present 
 an intermediate appearance. 
 
 Vfe have now seen that a naturalist might feel himself 
 fully justified in ranking the races of man as distinct spe- 
 cies; for he has found that they are distinguished by many 
 differences in structure and constitution, some being of 
 importance. These differences have also remained nearly 
 constant for very long periods of time. Our naturalist will 
 have been in some degree influenced by the enormous range 
 of man, which is a great anomaly in the class of mammals, 
 if mankind be viewed as a single species. He will have 
 been struck with the distribution of the several so-called 
 races, which accords with that of other undoubtedly dis- 
 tinct species of mammals. Finally, he might urge that the 
 mutual fertility of all the races has not as yet been fully 
 proved, and even if proved would not be an absolute proof 
 of their specific identity. 
 
 On the other side of the question, if our supposed nat- 
 uralist were to inquire whether the forms of man keep dis- 
 tinct like ordinary species when mingled together in large 
 numbers in the same country, he would immediately dis- 
 cover that this was by no means the case. In Brazil he 
 would behold an immense mongrel population of Negroes 
 and Portuguese; in Chili and other parts of South Amer- 
 ica he would behold the whole population consisting of In- 
 dians and Spaniards blended in various degrees, f In many 
 
 * " The Variation of Animals," etc., vol. ii, p. 92. 
 
 | M. de Quatrefages has given (" Anthropolog. Review," Jan., 
 1869, p. 22) an interesting account of the success and energy of the 
 Paulistas in Brazil, who are a much crossed race of Portuguese and 
 Indians, with a mixture of. the Wood of other races.
 
 198 THE DESCENT OF MAN. 
 
 parts of the same continent he would meet with the most 
 complex crosses between Negroes, Indians, and Europeans; 
 and judging from the vegetable kingdom such triple 
 crosses afford the severest test of the mutual fertility of the 
 parent forms. In one island of the Pacific he would find a 
 small population of mingled Polynesian and English blood; 
 and in the Fiji Archipelago a population of Polynesian and 
 Negritos crossed in all degrees. Many analogous cases 
 could be added; for instance, in Africa. Hence the races 
 of man are not sufficiently distinct to inhabit the same 
 country without fusion; and the absence of fusion affords 
 the usual and best test of specific distinctness. 
 
 Our naturalist would likewise be much disturbed as soon 
 as he perceived that the distinctive characters of all the 
 races were highly variable. This fact strikes every one on 
 first beholding the negro slaves in Brazil, who have been 
 imported from all parts of Africa. The same remark holds 
 good with the Polynesians, and with many other races. It 
 may be doubted whether any character can be named 
 which is distinctive of a race and is constant. Savages, 
 even within the limits of the same tribe, are not nearly so 
 uniform in character as has been often asserted. Hotten- 
 tot women offer certain peculiarities, more strongly marked 
 than those occurring in any other race, but these are 
 known not to be of constant occurrence. In the several 
 American tribes, color and hairiness differ considerably; as 
 does color to a certain degree, and the shape of the 
 features greatly, in the negroes of Africa. The shape of 
 the skull varies much in some races;* and so it is with 
 every other character. Now all naturalists have learned by 
 dearly bought experience how rash it is to attempt to define 
 species by the aid of inconstant characters. 
 
 But the most weighty of all the arguments against treat- 
 ing the races of man as distinct species, is that they gradu- 
 ate into each other, independently in many cases, as far as 
 we can judge, of their having intercrossed. Man has been 
 studied more carefully than any other animal, and yet there 
 is the greatest possible diversity among capable judges 
 whether he should be classed as a single species or race, or 
 
 * For instance, with the aborigines of America and Australia. Prof. 
 Huxley says (" Transact. Internal. Congress of Prehist. Arch.," 1868, 
 p. 105) that the skulls of many South Germans and Swiss are " as 
 short and as broad as those of the Tartars," etc.
 
 THE RACES OF MAN. 199 
 
 as two (Virey^, as three (Jacquinot), as four (Kant), five 
 (Blumeiibach), six (Buff on), seven (Hunter), eight (Agas- 
 siz), eleven (Pickering), fifteen (Bory St. Vincent), sixteen 
 (Desmoulins), twenty-two (Morton), sixty (Crawfurd), or 
 as sixty-three, according to Burke.* This diversity of 
 judgment does not prove that the races ought not to be 
 ranked as species, but it shows that they graduate into each 
 other, and that it is hardly possible to discover clear 
 i distinctive characters between them. 
 
 Every naturalist who has had the misfortune to under- 
 take the description of a group of highly varying organ- 
 isms has encountered cases (I speak after experience) 
 precisely like that of man; and if of a cautious disposition, 
 he will end by uniting all the forms which graduate into 
 each other under a single species; for he will say to him- 
 self that he has no right to give names to objects which he 
 cannot define. Cases of this kind occur in the order which 
 includes man, namely in certain genera of monkeys; while 
 in other genera, as in Cercopithecus, most of the species 
 can be determined with certainty. In the American genus 
 Cebus, the various forms are ranked by some naturalists as 
 species, by others as mere geographical races. Now if 
 numerous specimens of Cebus were collected from all parts 
 of South America, and those forms which at present appear 
 to be specifically distinct were found to graduate into each 
 other by close steps, they would usually be ranked as mere 
 varieties or races; and this course has been followed by 
 most naturalists with respect to the races of man. Never- 
 theless, it must be confessed that there are forms, at least 
 in the vegetable kingdom,! which we cannot avoid naming 
 as species, but which are connected together by numberless 
 gradations, independently of intercrossing. 
 
 Some naturalists have lately employed the term f ' sub- 
 species " to designate forms which possess many of the char- 
 acteristics of true species, but which hardly deserve so high 
 
 *See a good discussion on this subject in Waitz, " Introduct. to 
 Anthropology," Eng. translat., 1863, pp. 198-208, 227. I have taken 
 some of the above statements from H. Tuttle's " Origin and Antiquity 
 of Physical Man," Boston, 1866, p. 35. 
 
 f Prof. Nageli has carefully described several striking cases in his 
 " Botanische Mittheilungen, " B. ii, 1866, ss. 294-369. Prof. Asa 
 Gray has made analogous remarks on some intermediate forms in the 
 Composites of Nor
 
 200 THE DESCENT OF MAN. 
 
 a rank. Now if we reflect on the weighty arguments above 
 given, for raising the races of man to the dignity of species, 
 and the insuperable difficulties on the other side in denning 
 them, it seems that the term " sub-species " might here be 
 used with propriety. But from long habit the term " race " 
 will perhaps always be employed. The choice of terms is 
 only so far important in that it is desirable to use, as far as 
 possible, the same terms for the same degrees of difference. 
 Unfortunately this can rarely be done; for the larger genera 
 generally include closely-allied forms, which can be distin- 
 guished only with much difficulty, while the smaller genera 
 within the same family include forms that are perfectly dis- 
 tinct; yet all must be ranked equally as species. So again, 
 species within the same large genus by no means resemble 
 each other to the same degree; on the contrary, some of 
 them can generally be arranged in little groups round other 
 species, like satellites round planets.* 
 
 The question whether mankind consists of one or sev- 
 eral species has of late years been much discussed by anthro- 
 pologists, who are divided into the two schools of monogen- 
 ists and polygenists. Those who do not admit the prin- 
 ciple of evolution must look at species as separate creations, 
 or as in some manner as distinct entities; and they must 
 decide what forms of man they will consider as species by the 
 analogy of the method commonly pursued in ranking other 
 organic beings as species. But it is a hopeless endeavor to 
 decide this point, until some definition of the term 
 "species "is generally accepted; and the definition must 
 not include an indeterminate element such as an act of 
 creation. We might as well attempt without any definition 
 to decide whether a certain number of houses should be 
 called a village, town or city. We have a practical illus- 
 tration of the difficulty in the never-ending doubts whether 
 many closely-allied mammals, birds, insects and plants, which 
 represent each other respectively in North America and 
 Europe, should be ranked as species or geographical races; 
 and the like holds true of the productions of many islands 
 situated at some little distance from the nearest continent. 
 
 Those naturalists, on the other hand, who admit the 
 principle of evolution, and this is now admitted by the 
 
 *" Origin of Species," 5th edit. p. 68.
 
 THE RACES OF MAN. 201 
 
 majority of rising men, will feel no doubt that all the races 
 of man are descended from a single primitive stock ; 
 whether or not they may think fit to designate the races as 
 distinct species, for the sake of expressing their amount of 
 difference.* With our domestic animals the question 
 whether the various races have arisen from one or more 
 species is somewhat different. Although it may be admit- 
 ted that all the races, as well as all the natural species 
 within the same genus, have sprung from the same primi- 
 tive stock, yet it is a fit subject for discussion, whether all 
 the domestic races of the dog, for instance, have acquired 
 their present amount of difference since some one species 
 was first domesticated by man; or whether they owe some 
 of their characters to inheritance from distinct species, 
 which had already been differentiated in a state of nature. 
 With man no such question can arise, for he cannot be said 
 to have been domesticated at any particular period. 
 
 During an early stage in the divergence of the races of 
 man from a common stock, the differences between the 
 races and their number must have been small; consequently 
 as far as their distinguishing characters are concerned, they 
 then had less claim to rank as distinct species than the 
 existing so-called races. Nevertheless, so arbitrary is the 
 term of species, that such early races would perhaps have 
 been ranked by some naturalists as distinct species, if their 
 differences, although extremely slight, had been more con- 
 stant than they are at present, and had not graduated into 
 each other. 
 
 It is, however, possible, though far from probable, that 
 the early progenitors of man might formerly have diverged 
 much in character, until they became more unlike each 
 other than any now existing races; but that subsequently, 
 as suggested by Vogt, f they converged in character. When 
 man selects the offspring of two distinct species for the 
 same object, he sometimes induces a considerable amount 
 of convergence, as far as general appearance is concerned. 
 This is the case, as shown by Von Nathusius,t with the 
 
 *See Prof. Huxley to this effect in the " Fortnightly Review," 
 1865, p. 275. 
 
 f " Lectures on Man," Eng. translat., 1864, p. 468. 
 
 t"Die,Racen des Schweines," 1860, s. 46. " Vorstudien fur 
 Geschichte, etc. Scliweineschadel," 1864, s. 104. With respect to 
 cattle, see M. de Qiiatrefages, "Unite de 1'Espece Humaine," 1861, 
 p. 119.
 
 202 THE DESCENT OF MAN. 
 
 improved breeds of the pig, which are descended from two 
 distinct species; and in a less marked manner with the 
 improved breeds of cattle. A great anatomist, Gratiolet, 
 maintains that the anthropomorphous apes do not form a 
 natural sub-group ; but that the orang is a highly devel- 
 oped gibbon or semnopithecus, the chimpanzee a highly 
 developed macacus, and the goriHa a highly developed man- 
 drill. If this conclusion, which rests almost exclusively on 
 brain-characters, be admitted, we should have a case of con- 
 vergence at least in external characters, for the anthropomor- 
 phous apes are certainly more like each other in many points 
 than they are to other apes. All analogical resemblances, as of 
 a whale to a fish, may indeed be said to be cases of con- 
 vergence; but this term has never been applied to super- 
 ficial and adaptive resemblances. It would, however, be 
 extremely rash to attribute to convergence close similarity 
 of character in many points of structure among the modi- 
 fied descendants of widely distinct beings. The form of a 
 crystal is determined solely by the molecular forces, and it 
 is not surprising that dissimilar substances should some- 
 times assume the same form; but with organic beings we 
 should bear in mind that the form of each depends on an 
 infinity of complex relations, namely, on variations due to 
 causes far too intricate to be followed on the nature of 
 the variations preserved, these depending on the physical 
 conditions, and still more on the surrounding organisms 
 which compete with each and lastly, on inheritance (in 
 itself a fluctuating element) from innumerable progenitors, 
 all of which have have had their forms determined through 
 equally complex relations. It appears incredible that the 
 modified descendants of two organisms, if these differed 
 from each other in a marked manner, should ever after- 
 ward converge so closely as to lead to a near approach to 
 identity throughout their whole organization. In the case 
 of the convergent races of pigs above referred to, evidence 
 of their descent from two primitive stocks is, according to 
 Von Nathusius, still plainly retained in certain bones of 
 their skulls. If the races of man had descended, as is sup- 
 posed by some naturalists, from two or more species which 
 differed from each other as much, or nearly as much, as 
 does the orang from the gorilla it can hardly be doubted 
 that marked differences in the structure of certain bones 
 would still be discoverable in man as he now exists.
 
 THE RACES OF MAN. 203 
 
 Although the existing races of man differ in many re- 
 spects as in color, hair, shape of skull, proportions of the 
 body, etc., yet if their whole structure be taken into con- 
 sideration they are found to resemble each other closely in 
 a multitude of points. Many of these are of so unimpor- 
 tant or of so singular a nature that it is extremely improb- 
 able that they should have been independently acquired by 
 aboriginally distinct species or races. The same remark 
 holds good with equal or greater force with respect to the 
 numerous points of mental similarity between the most 
 distinct races of man. The American aborigines, Negroes 
 and Europeans are as different from each other in mind as 
 any three races that can be named; yet I was incessantly 
 struck while living with the Fuegians on board the 
 " Beagle" with the many little traits of character showing 
 how similar their minds were to ours; and so it was with 
 a full-blooded negro with whom I happened once to be 
 intimate. 
 
 He who will read Mr. Tylor's and Sir J. Lubbock's in- 
 teresting works* can hardly fail to be deeply impressed 
 with the close similarity between the men of all races in 
 tastes, dispositions and habits. This is shown by the pleas- 
 ure which they all take in dancing, rude music, painting, 
 tattooing and otherwise decorating themselves; in their 
 mutual comprehension of gesture-language, by the same 
 expression in their features, and by the same inarticulate 
 cries, when excited by the same emotions. This similarity, 
 or rather identity, is striking, when contrasted with the 
 different expressions and cries made by distinct species of 
 monkeys. There is good evidence that the art of shooting 
 with bows and arrows has not been handed down from any 
 common progenitor of mankind, yet as Westropp and 
 Nilsson have remarked, \ the stone arrow-heads, brought 
 from the most distant parts of the world, and manufactured 
 at the most remote periods, are almost identical; and this 
 fact can only be accounted for by the various races having 
 similar inventive or mental powers. The same observation 
 
 * Tylor's " Early History of Mankind," 1865; with respect to ges- 
 ture-language, see p. 54. Lubbock's ' Prehistoric Times," 2d edit., 
 
 J"0n Analogous Forms of Implements," in "Memoirs of Anthro- 
 og. Soc.," by H. M. Westropp. "The Primitive Inhabitants of 
 candinavia," Eng. translate edited by Sir J. Lubbock, 1868, p. 104.
 
 204 THE DESCENT OF MAN. 
 
 has been made by archaeologists * with respect to certain 
 widely-prevalent ornaments, such as zig-zags, etc.; and 
 with respect to various simple beliefs and customs, such as 
 the burying of the dead under megalithic structures. I 
 remember observing in South America f that there, as in 
 so many other parts of the world, men have generally 
 chosen the summits of lofty hills to throw up piles of 
 stones, either as a record of some remarkable event, or for 
 burying their dead. 
 
 Now when naturalists observe a close agreement in 
 numerous small details of habits, tastes, and dispositions 
 between two or more domestic races, or between nearly 
 allied natural forms, they use this fact as an argument that 
 they are descended from a common progenitor who was 
 thus endowed; and consequently that all should be classed 
 under the same species. The same argument may be 
 applied with much force to the races of man. 
 
 As it is improbable that the numerous and unimportant 
 points of resemblance between the several races of man in 
 bodily structure and mental faculties (I do not here refer to 
 similar customs) should all have been independently 
 acquired, they must have been inherited from progenitors 
 who had these same characters. We thus gain some insight 
 into the early state of man, before he had spread step by 
 step over the face of the earth. The spreading of man to 
 regions widely separated by the sea, no doubt, preceded any 
 great amount of divergence of character in the several 
 races; for otherwise we should sometimes meet with the 
 same race in distinct continents; and this is never the case. 
 Sir J. Lubbock, after comparing the arts now practiced by 
 savages in all parts of the world, specifies those which man 
 could not have known, when he first wandered from his 
 original birthplace; for if once learned they would never 
 have been forgotten. J He thus shows that "the spear, 
 which is but a development of the knife-point, and the 
 club, which is but a long hammer, are the only things left." 
 He admits, however, that the art of making fire probably 
 had been already discovered, for it is common to all the 
 
 *Westropp, "On Cromlechs," etc., "Journal of Ethnological Soc.," 
 as given in " Scientific Opinion," June 2, 1869, p. 3. 
 
 f "Journal of Researches; Voyage of the ' Beagle,' " p. 46. 
 j " Prehistoric Times," 1869, p. 574.
 
 THE RAGES OF MAN. 205 
 
 races now existing, and was known to the ancient cave- 
 inhabitants of Europe. Perhaps the art of making rude 
 canoes or rafts was likewise known; but as man existed at a 
 remote epoch, when the land in many places stood at a very 
 different level to what it does now, he would have been able, 
 without the aid of canoes, to have spread widely. Sir J. 
 Lubbock further remarks how improbable it is that out 
 earliest ancestors could have " counted as high as ten, con- 
 sidering that so many races now in existence cannot get 
 beyond four." Nevertheless, at this early period, the intel- 
 lectual and social faculties of man could hardly have been 
 inferior in any extreme degree to those possessed at present 
 by the lowest savages; otherwise primeval man could not 
 have been so eminently successful in the struggle for life, 
 as proved by his early and wide diffusion. 
 
 From the fundamental differences between certain lan- 
 guages, some philologists have inferred that when man first 
 became widely diffused, he was not a speaking animal; but 
 it may be suspected that languages, far less perfect than 
 any now spoken, aided by gestures, might have been used, 
 and yet have left no traces on subsequent and more highly- 
 de\ eloped tongues. Without the use of some language, 
 however imperfect, it appears doubtful whether man's intel- 
 lect could have risen to the standard implied by his domi- 
 nant position at an early period. 
 
 Whether primeval man, when he possessed but few arts, 
 and those of the rudest kind, and when his power of lan- 
 guage was extremely imperfect, would have deserved to be 
 called man, must depend on the definition which we 
 employ. In a series of forms graduating insensibly from 
 some ape-like creature to man as he now exists, it would be 
 impossible to fix on any definite point when the term 
 " man " ought to be used. But this is a matter of very 
 little importance. So again, it is almost a matter of indif- 
 ference whether the so-called races of man are thus desig- 
 nated, or are ranked as species or sub-species; but the latter 
 term appears the more appropriate. Finally, we may con- 
 clude that when the principle of evolution is generally 
 accepted, as it surely will be before long, the dispute 
 between the monogenists and the polygenists will die a silent 
 and unobserved death. 
 
 One other question ought not to be passed over without
 
 206 THE DESCENT OF MAN. 
 
 notice, namely, whether, as is sometimes assumed, each 
 sub-species or race of man has sprung from a single pair of 
 progenitors. With our domestic animals a new race can 
 readily be formed by carefully matching the varying off- 
 spring from a single pair, or even from a single individual 
 possessing some new character; but most of our races have 
 been formed, not intentionally from a selected pair, but 
 unconsciously by the preservation of many individuals 
 which have varied, however slightly, in some useful or 
 desired manner. If in one country stronger and heavier 
 horses, and in another country lighter and fleeter ones, were 
 habitually preferred, we may feel sure that two distinct 
 sub-breeds would be produced in the course of time, with- 
 out any one pair having been separated and bred from, in 
 either country. Many races have been thus formed, and 
 their manner of formation is closely analogous to that of 
 natural species. We know, also, that the horses taken to the 
 Falkland Islands have, during successive generations, 
 become smaller and weaker, while those which have run 
 wild on the Pampas have acquired larger and coarser heads; 
 and such changes are manifestly due, not to any one pair, 
 but to all the individuals having been subjected to the 
 same conditions, aided, perhaps, by the principle of rever- 
 sion. The new sub-breeds in such cases are not descended 
 from any single pair, but from many individuals which 
 have varied in different degrees, but in the same general 
 manner; and we may conclude that the races of man have 
 been similarly produced, the modifications being either the 
 direct result of exposure to different conditions, or the 
 indirect result of some form of selection. But to this 
 latter subject we shall presently return. 
 
 On the Extinction of the Races of Man. The partial or 
 complete extinction of many races and sub-races of man is 
 historically known. Humboldt saw in South America a 
 parrot which was the sole living creature that could speak 
 a word of the language of a lost tribe. Ancient monuments 
 and stone implements found in all parts of the world, about 
 which no tradition has been preserved by the present 
 inhabitants, indicate much extinction. Some small and 
 broken tribes, remnants of former races, still survive in 
 isolated and generally mountainous districts. In Europe
 
 THE RACES OF MAN. 207 
 
 the ancient races were all, according to Schaaffhausen,* 
 "lower in the scale than the rudest living savages ;" they 
 must therefore have differed, to a certain extent, from any 
 existing race. The remains described by Prof. Broca from 
 Les Eyzies, though they unfortunately appear to have 
 belonged to a single family, indicate a race with a most 
 singular combination of low or simious, and of high char- 
 acteristics. This race is " entirely different from any 
 other, ancient or modern, that we have heard of."f It 
 differed, therefore, from the quaternary race of the caverns 
 of Belgium. 
 
 Man can long resist conditions which appear extremely 
 unfavorable for his existence. J He has long lived in the 
 extreme regions of the north, with no wood for his canoes 
 or implements, and with only blubber as fuel and melted 
 snow as drink. In the southern extremity of America the 
 Fuegians survive without the protection of clothes, or of 
 any building worthy to be called a hovel. In South Africa 
 the aborigines wander over arid plains, where dangerous 
 beasts abound. Man can withstand the deadly influence 
 of the Terai at the foot of the Himalaya and the pestilen- 
 tial shores of tropical Africa. 
 
 Extinction follows chiefly from the competition of tribe 
 with tribe and race with race. Various checks are always 
 in action, serving to keep down the numbers of each 
 savage tribe such as periodical famines, nomadic habits 
 and the consequent deaths of infants, prolonged suckling, 
 wars, accidents, sickess, licentiousness, the stealing of 
 women, infanticide, and especially lessened fertility. If 
 any one of these checks increases in power, even slightly, 
 the tribe thus affected tends to decrease ; and when of two 
 adjoining tribes one becomes less numerous and less power- 
 ful than the other, the contest is soon settled by war, 
 slaughter, cannibalism, slavery, and absorption. Even 
 when a weaker tribe is not thus abruptly swept away, if it 
 once begins to decrease, it generally goes on decreasing 
 until it becomes extinct. 
 
 * Translation in "Anthropological Review," Oct., 1868, p. 431. 
 
 {"Transact. Tnternat. Congress of Prehistoric Arch.," 1868, pp. 
 172-175. See also Broca (translation) in " Anthropological Review," 
 Oct., 1868, p. 410. 
 
 Dr. Gerland, " Ueberdas Aussterben der Naturvolker," 1868, s,8g. 
 
 gGerland (ibid, s. 13) gives facts in support of this statement.
 
 208 THE DESCENT OF MAN. 
 
 When civilized nations come into contact with barba- 
 rians the struggle is short, except where a deadly climate 
 gives its aid to the native race. Of the causes which lead 
 to the victory of civilized nations some are plain and sim- 
 ple, others complex and obscure. We can see that the 
 cultivation of the land will be fatal in many ways to sav- 
 ages, for they cannot, or will not, change their habits. 
 New diseases and vices have in some cases proved highly 
 destructive; and it appears that a new disease often causes 
 much death until those who are most susceptible to its 
 destructive influence are gradually weeded out;* and so it 
 may be with the evil effects from spirituous liquors, as well 
 as with the unconquerably strong taste for them shown by 
 so many savages. It further appears, mysterious as is the 
 fact, that the first meeting of distinct and separated people 
 generates disease, f Mr. Sproat, who in Vancouver Island 
 closely attended to the subject of extinction, believed that 
 changed habits of life, consequent on the advent of Euro- 
 peans, induces much ill -health. He lays, also, great stress 
 on the apparently trifling cause that the natives become 
 " bewildered and dull by the new life around them; they 
 lose the motives for exertion and get no new ones in their 
 place. "I 
 
 The grade of their civilization seems to be a most impor- 
 tant element in the success of competing nations. A few 
 centuries ago Europe feared the inroads of Eastern barba- 
 rians; now any such fear would be ridiculous. It is a more 
 curious fact, as Mr. Bagehot has remarked, that savages 
 did not formerly waste away before the classical nations as 
 they now do before modern civilized nations; had they 
 done so the old moralists would have mused over the event; 
 but there is no lament in any writer of that period over the 
 perishing barbarians. The most potent of all the causes 
 of extinction appears in many cases to be lessened fertility 
 
 *See remarks to this effect in Sir H. Holland's "Medical Notes 
 and Reflections," 1839, p. 390. 
 
 fl have collected ("Journal of Researches, Voyage of the 
 Beagle,'" p. 435) a good many cases bearing on this subject; see 
 also Gerland, ibid, s. 8. Poeppig speaks of the " breath of civiliza- 
 tion as poisonous to savages. " 
 
 J Sproat, " Scenes and Studies of Savage Life," 1868, p. 284, 
 
 g Bagehot., "Physics and Politics," "Fortnightly Review," Aprf 
 J, 1868, p. 455.
 
 THE RACES OF MAN. 209 
 
 and ill-health, especially among the children, arising from 
 changed conditions of life, notwithstanding that the new 
 conditions may not be injurious in themselves. I am much 
 indebted to Mr. H. H. Howorth for having called my 
 attention to this subject and for having given me informa- 
 tion respecting it. I have collected the following cases: 
 
 When Tasmania was first colonized the natives were 
 roughly estimated by some at 7,000, and by others at 20,000. 
 Their number was soon greatly reduced,, chiefly by fighting 
 with the English and with each other. After the famous 
 hunt by all the colonists, when the remaining natives deliv- 
 ered themselves up to the government, they consisted only of 
 1'20 individuals,* who were in 1832 transported to Flinders 
 Island. This island, situated between Tasmania and Aus- 
 tralia, is forty miles long, and from twelve to eighteen miles 
 broad; it seems healthy, and the natives were well treated. 
 Nevertheless, they suffered greatly in health. In 1834 they 
 consisted (Bonwick, p. 250) of forty-seven adult males, 
 forty-eight adult females, and sixteen children, or in all of 
 one hundred and eleven souls. In 1835 only one hundred 
 were left. As they continued rapidly to decrease, and as 
 they themselves thought that they should "not perish so 
 quickly elsewhere, they were removed in 1847 to Oyster 
 Cove in the southern part of Tasmania. They then con- 
 sisted (Dec. 20, 1847) of fourteen men, twenty-two women 
 and ten children, f But the change of site did no good. 
 Disease and death still pursued them, and in 1864 one man 
 (who died in 1869) and three elderly women alone survived. 
 The infertility of the women is even a more remarkable 
 fact than the* liability of all to ill-health and death. At 
 the time when only nine women were left at Oyster Cove 
 they told Mr. Bouwick (p. 386) that only two had ever 
 borne children; and these two had together produced only 
 three children! 
 
 With respect to the cause of this extraordinary state of 
 things Dr. Story remarks that death followed the attempts 
 to civilize the natives. " If left to themselves to roam as 
 they were wont and undisturbed they would have reared 
 more children and there would have been less mortality." 
 
 * All the statements here given are taken from "The Last of the 
 Tasmanians," by J. Bonwick, 1870. 
 
 f This is the statement of the Governor of Tasmania, Sir W. Deni 
 son, " Varieties of Vice-Regal Life," 1870, vol. i, p. 67.
 
 210 THE DESCENT OF MAN. 
 
 Another careful observer of the natives, Mr. Davis, remarks, 
 " The births have been few and the deaths numerous. 
 This may have been in a great measure owing to their 
 change of living and food; but more so to their banishment 
 from the mainland of Van Diemen's Land and consequent 
 depression of spirits " (Bonwick, pp. 388, 390). 
 
 Similar facts have been observed in two widely different 
 parts of Australia. The celebrated explorer, Mr. Gregory, 
 told Mr. Bonwick, that in Queensland "the want of repro- 
 duction was being already felt with the blacks, even in the 
 most recently settled parts, and that decay would set 
 in." Of thirteen aborigines from Shark's Bay who visited 
 Murchison River, twelve died of consumption within three 
 months.* 
 
 The decrease of the Maories of New Zealand has been 
 carefully investigated by Mr. Fenton, in an admirable 
 report, from which all the following statements, with one 
 exception, are taken, f The decrease in number since 1830 
 is admitted by every one, including the natives themselves, 
 and is still steadily progressing. Although it has hitherto 
 been found impossible to take an actual census of the 
 natives, their " numbers were carefully estimated by resi- 
 dents in many districts. The result seems trustworthy, 
 and shows that during the fourteen years, previous to 1858, 
 the decrease was 19.42 per cent. Some of the tribes, thus 
 carefully examined, lived above a hundred miles apart, 
 some on the coast, some inland; and their means of sub- 
 sistence and habits differed to a certain extent (p. 28). 
 The total number in 1858 was believed to be 53,700, and 
 in 1872, after a second interval of fourteen years, another 
 census was taken, and the number is given as only 
 36,359, showing a decrease of 32.29 per cent. ! J 
 Mr. Fenton, after showing in detail the insufficiency of 
 the various causes usually assigned in explanation of this 
 extraordinary decrease, such as new diseases, the profligacy 
 of the women, drunkenness, wars, etc., concludes on 
 weighty grounds that it depends chiefly on the unproduc- 
 
 *For these cases see Bonwick 's "Daily Life of the Tasmanians," 
 1870, p. 90; and the " Last of the Tasmanians," 1870, p. 386. 
 
 f ' ' Observations on the Aboriginal Inhabitants of New Zealand " 
 published by the Government, 1859. 
 
 t " New Zealand," by Alex. Kennedy, 1873, p. 47.
 
 THE RACES OF MAN. 211 
 
 tiveness of the women and on the extraordinary mortality 
 of the young children (pp. 31, 34). In proof of this he 
 shows (p. 33) that in 1844 there was one non-adult for 
 every 2.57 adults; whereas in 1858 there was only one non- 
 adult for every 3.27 adults. The mortality of the adults is 
 also great. He adduces as a further cause of the decrease 
 the inequality of the sexes; for fewer females are born than 
 males. To this latter point, depending perhaps on a widely 
 distinct cause, I shall return in a future chapter. Mr. 
 Fenton contrasts with astonishment the decrease in New 
 Zealand with the increase in Ireland; countries not very 
 dissimilar in climate, and where the inhabitants now follow 
 nearly similar habits. The Maories themselves (p. 35) 
 " attribute their decadence, in some measure, to the intro- 
 duction of new food and clothing, and the attendant 
 change of habits;" and it will be seen, when we consider 
 the influence of changed conditions on fertility, that they 
 are probably right. The diminution began between the 
 years 1830 and 1840; and Mr. Fenton shows (p. 40) that 
 about 1830, the art of manufacturing putrid corn (maize), 
 by long steeping in water, was discovered and largely prac- 
 ticed; and this proves that a change of habits was begin- 
 ning among the natives, even when New Zealand was only 
 thinly inhabited by Europeans. When I visited the Bay 
 of Islands in 1835, the dress and food of the inhabitants 
 had already been much modified ; they raised potatoes, 
 maize and other agricultural produce, and exchanged them 
 for English manufactured goods and tobacco. 
 
 It is evident from many statements in the life of Bishop 
 Patteson,* that the Melanesians of the New Hebrides and 
 neighboring archipelagoes, suffered to an extraordinary 
 degree in health, and perished in large numbers, when they 
 were removed to New Zealand, Norfolk Island and other 
 salubrious places, in order to be educated as missionaries. 
 
 The decrease of the native population of the Sandwich 
 Islands is as notorious as that of New Zealand. It has 
 been roughly estimated by those best capable of judging, 
 that when Cook discovered the Islands in 1779, the popula- 
 tion amounted to about 300,000. According to a loose 
 census in 1823, the numbers then were 142,050. In 1832, 
 
 *"Life 'of J. C. Patteson," by C. M. Younge, 1874; see more 
 especially vol. i, p. 530.
 
 212 
 
 THE DESCENT OF MAN. 
 
 and at several subsequent periods, an accurate census was 
 officially taken, but I have been able to obtain only the fol- 
 lowing returns: 
 
 
 
 Annual rate of decrease per 
 
 YBAB. 
 
 NATIVE POPULATION. 
 
 (Except during 1832 and 1836, 
 when the few foreigners in 
 the islands were included.) 
 
 cent., assuming it to have 
 been uniform between the 
 successive censuses ; these 
 censuses being taken at ir- 
 regular intervals. 
 
 1832 
 
 130,313 
 
 
 
 
 
 
 4.46 
 
 
 1836 
 
 108,579 
 
 
 
 
 
 
 
 2.47 
 
 
 1853 
 
 71,019 
 
 
 
 
 
 
 
 0.81 
 
 
 1860 
 
 67,084 
 
 
 
 
 
 
 
 2.18 
 
 
 1866 
 
 58,765 
 
 
 
 
 
 
 
 2.17 
 
 
 1872 
 
 51,531 
 
 
 
 We here see that in the interval of forty years, between 
 1832 and 1872, the population has decreased no less than 
 sixty-eight per cent. ! This has been attributed by most 
 writers to the profligacy of the women, to former bloody 
 wars, and to the severe labor imposed on conquered tribes 
 and to newly introduced diseases, which have been on sev- 
 eral occasions extremely destructive. No doubt these and 
 other such causes have been highly efficient, and may 
 account for the extraordinary rate of decrease between the 
 years 1832 and 1836; but the most potent of all the causes 
 seems to be lessened fertility. According to Dr. Kuschen- 
 berger of the United States Navy, who visited these islands 
 between 1835 and 1837, in one district of Hawaii, only 
 twenty-five men out of 1,134, and in another district only 
 ten out of 637, had a family with as many as three 
 children. Of eighty married women, only thirty-nine had 
 ever borne children ; and " the official report gives an 
 average of half a child to each married couple in the 
 whole island/' This is almost exactly the same average as 
 with the Tasmanians at Oyster Cove. Jarves, who pub- 
 lished his history in 1843, says that "families who have 
 three children are freed from all taxes; those having more,
 
 THE RACES OF MAN. 213 
 
 are rewarded by gifts of land arid other encouragements." 
 This unparalleled enactment by the government well shows 
 how infertile the race had become. The Eev. A. Bishop 
 stated in the Hawaiian ''Spectator " in 1839, that a large 
 proportion of the children die at early ages, and Bishop 
 Staley informs me that this is still the case, just as in New 
 Zealand. This has been attributed to the neglect of the 
 children by the women, but it is probably in large part due 
 to innate weakness of constitution in the children, in rela- 
 tion to the lessened fertility of their parents. There is, 
 moreover, a further resemblance to the case of New Zeal- 
 and, in the fact that there is a large excess of male over 
 female births; the census of 1872 gives 31,650 males to 
 25,247 females of all ages, that is 125.36 males for every 
 100 females; whereas in all civilized countries the females 
 exceed the males. No doubt the profligacy of the women 
 may in part account for their small fertility; but their 
 changed habits of life is a much more probable cause, and 
 which will at the same time account for the increased mor- 
 tality, especially of the children. The islands were visited 
 by Cook in 1779, by Vancouver in 1794, and often subse- 
 quently by whalers. In 1819 missionaries arrived, and 
 found that idolatry had been already abolished, and other 
 changes effected by the king. After this period there was 
 a rapid change in almost all the habits of life of the natives, 
 and they soon became " the most civilized of the Pacific 
 Islanders." One of my informants, Mr. Coan, who was 
 born on the islands, remarks that the natives have under- 
 gone a greater change in their habits of life in the course 
 of fifty years than Englishmen during a thousand years. 
 From information received from Bishop Staley, it does 
 not appear that the poorer classes have ever much changed 
 their diet, although many new kinds of fruit have been 
 introduced, and the sugar-cane is in universal use. Owing 
 however, to their passion for imitating Europeans, they 
 altered their manner of dressing at an early period, and 
 the use of alcoholic drinks became very general. Although 
 these changes appear inconsiderable, I can well believe, 
 from what is known with respect to animals, that they 
 might suffice to lessen the fertility of the natives.* 
 
 * The foregoing statements are taken chiefly from the following 
 works: " Jarves' History of the Hawaiian Islands," 1843, pp. 400- 
 407, Cbeever, "Life in the Sandwich Islands," 1851, p. 277.
 
 214 TUB DESCENT OF MAN. 
 
 Lastly, Mr. Macnamara states * that the low and de 
 graded inhabitants of the Andaman Islands, on the eastern 
 side of the Gulf of Bengal, are " eminently susceptible to 
 any change of climate; in fact, take them away from their 
 island homes, and they are almost certain to die, and that 
 independently of diet or extraneous influences." He further 
 states that the inhabitants of the Valley of Nepal, which is 
 extremely hot in summer, and also the various hill-tribes 
 of India, suffer from dysentery and fever when on the 
 plains; and they die if they attempt to pass the whole year 
 there. 
 
 We thus see that many of the wilder races of man are 
 apt to suffer much in health when subjected to changed 
 conditions or habits of life and not exclusively from being 
 transported to a new climate. Mere alterations in habits, 
 which do not appear injurious in themselves, seem to have this 
 same effect; and in several cases the children are particularly 
 liable to suffer. It has often been said, as Mr. Macnamara 
 remarks, that man can resist with impunity the greatest 
 diversities of climate and other changes; but this is true 
 only of the civilized races. Man in his wild condition 
 seems to be in this respect almost as susceptible as his near- 
 est allies, the anthropoid apes, which have never yet sur- 
 vived long, when removed from their native country. 
 
 Lessened fertility from changed conditions, as in the case 
 of the Tasmanians, Maories, Sandwich Islanders, and 
 apparently the Australians, is still more interesting than 
 their liability to ill-health and death; for even a slight 
 degree of infertility, combined with those other causes 
 which tend to check the increase of every population, would 
 sooner o/ later lead to extinction. The diminution of fertility 
 may be explained in some cases by the profligacy of the 
 women (as until lately with the Tahitians), but Mr. Fenton 
 has shown that this explanation by no means suffices with 
 the New Zealanders, nor does it with the Tasmanians. 
 
 Ruschenberger is quoted by Bonwick, "Last of the Tasmanians," 
 1870, p. 378. Bishop is quoted by Sir E. Belcher, " Voyage Round 
 the World," 1843, vol. i, p. 272. I owe the census of the several 
 years to the kindness of Mr. Coan, at the request of Dr. Youmans, of 
 New York; and in most cases I have compared the Youmans figures 
 with those given in several of the above-named works. I have 
 omitted the census for 1850, as I have seen two widely different num- 
 bers given. 
 * "The Indian Medical Gazette," Nov. 1, 1871, p. 240.
 
 THE RACES OF MAN. 215 
 
 In the paper above quoted, Mr. Macnamara gives reasons 
 for believing that the inhabitants of districts subject to 
 malaria are apt to be sterile; but this cannot apply in sev- 
 eral of the above cases. Some writers have suggested that 
 the aborigines of islands have suffered in fertility and 
 health from long continued inter-breeding; but in the above 
 cases infertility has coincided too closely with the arrival 
 of Europeans for us to admit this explanation. Nor have 
 we at present any reason to believe that man is highly sen- 
 sitive to the evil effects of inter-breeding, especially in 
 areas so large as New Zealand and the Sandwich Archi- 
 pelago with its diversified stations. On the contrary, it is 
 Known that the present inhabitants of Norfolk Island are 
 nearly all cousins or near relations, as are the Todas in 
 India, and the inhabitants of some of the Western Islands 
 of Scotland; and yet they seem not to have suffered in 
 fertility.* 
 
 A much more probable view is suggested by the analogy 
 of the lower animals. The reproductive system can be 
 shown to be susceptible to an extraordinary degree (though 
 why we know not) to changed conditions of life; and this 
 susceptibility leads both to beneficial and to evil results. 
 A large collection of facts on this subject is given in chap- 
 ter xviii, of volume ii, of my " Variation of Animals and 
 Plants under Domestication." I can here give only the 
 briefest abstract; and every one interested in the subject 
 may consult the above work. Very slight changes increase 
 the health, vigor and fertility of most or all organic beings, 
 while other changes are known to render a large number of 
 animals sterile. One of the most familiar cases is that of 
 tamed elephants not breeding in India; though they often 
 breed in Ava, where the females are allowed to roam about 
 the forests to some extent, and are thus placed under more 
 natural conditions. The case of various American mon- 
 keys, both sexes of which have been kept for many years 
 together in their own countries, and yet have very rarely 
 or never bred, is a more apposite instance, because of their 
 relationship to man. It is remarkable how slight a change 
 
 * On the close relationship of the Norfolk Islanders, see Sir W. 
 Denison, "Varieties of Vice-Regal Life," vol. i, 1870, p. 410. For 
 the, Todas, -see Col. Marshall's work, 1873, p. 110. For the Western 
 Islands of Scotland, Dr. Mitchell, "Edinburgh Medical Journal," 
 March to June, 1865.
 
 216 THE DESCENT OF MAN. 
 
 in the conditions often induces sterility in a wild animal 
 when captured; and this is the more strange as all our 
 domesticated animals have become more fertile than they 
 were in a state of nature; and some of them can resist the 
 most unnatural conditions with undiminished fertility.* 
 Certain groups of animals are much more liable than others 
 to be affected by captivity; and generally all the species of 
 the same group are affected in the same manner. But 
 sometimes a single species in a group is rendered sterile., 
 while the others are not so; on the other hand, a single 
 species may retain its fertility while most of the others fail 
 to breed. The males and females of some species when 
 confined, or when allowed to live almost but not quite free, 
 in their native country never unite; others thus circum- 
 stanced frequently unite but never produce offspring; 
 others again produce some offspring, but fewer than in a 
 state of nature; and as bearing on the above cases of man 
 it is important to remark that the young are apt to be 
 weak and sickly, or malformed, and to perish at an early 
 age. 
 
 Seeing how general is this law of the susceptibility of the 
 reproductive system to changed conditions of life, and that 
 it holds good with our nearest allies, the Quadrimiana, I 
 can hardly doubt that it applies to man in his primeval state. 
 Hence, if savages of any race are induced suddenly to change 
 their habits of life they become more or less sterile, and 
 their young offspring suffer in health in the same manner 
 and from the same cause as do the elephant and hunting- 
 leopard in India, many monkeys in America, and a host 
 of animals of all kinds on removal from their natural 
 conditions. 
 
 We can see why it is that aborigines, who have long 
 inhabited islands, and who must have been long exposed to 
 nearly uniform conditions, should be specially affected by 
 any change in their habits, as seems to be the case. Civil- 
 ized races can certainly resist changes of all kinds far 
 better than savages ; and in this respect they resemble 
 domesticated animals, for though the latter sometimes 
 suffer in health (for instance European dogs in India), yet 
 they are rarely rendered sterile, though a few such 
 
 *For the evidence on this head, see " Variation of Animals," etc., 
 vol. ii, p. 111.
 
 THE RACES OF MAN. 217 
 
 instances have been recorded.* The immunity of civilizeu. 
 races and domesticated animals is probably dne to their 
 having been subjected to a greater . extent, and, therefore, 
 having grown somewhat more accustomed, to diversified or 
 varying conditions, than the majority of wild animals; and 
 to their having formerly immigrated or been carried from 
 country to country, and to different families or sub-races 
 having inter-crossed. It appears that a cross with civilized 
 races at once gives to an aboriginal race an immunity from 
 the evil consequences of changed conditions. Thus the 
 crossed offspring from the Tahitians and English, when 
 settled in Pitcairn Island, increased so rapidly that the 
 island was soon overstocked; and in June, 185G, they were 
 removed to Norfolk Island. They then consisted of 
 60 married persons and 13-4 children, making a total of 
 194. Here they likewise increased so rapidly that, 
 although 16 of them returned to Pitcairn Island in 1859, 
 they numbered in January, 1868, 300 souls; the males and 
 females being in exactly equal numbers. What a contrast 
 does this case present with that of the Tasmanians; the 
 Norfolk Islanders increased in only twelve and a half years 
 from 194 to 300; whereas the Tasmanians decreased during 
 15 years from 120 to 46, of which latter number only 10 
 were children, f 
 
 So again in the interval between the census of 1866 and 
 1872 the natives of full blood in the Sandwich Islands 
 decreased by 8,081, while the half-castes, who are believed 
 to be healthier, increased by 847; but I do not know 
 whether the latter number includes the offspring from 
 the half-castes, or only the half-castes of the first genera- 
 tion. 
 
 The cases which I have here given all relate to aborigines 
 who have been subjected to new conditions as the result of 
 the immigration of civilized men. But sterility and ill- 
 health would probably follow if savages were compelled by 
 any cause, such as the inroad of a conquering tribe, to 
 desert their homes and to change their habits. It is an 
 
 * " Variation of Animals," etc., vol. ii, p. 16. 
 
 f These details are taken from " The Mutineers of the ' Bounty," " 
 by Lady Belcher, 1870; and from "Pitcairn Island," ordered to be 
 printed by- the House of Commons, May 29, 1863. The following 
 statements about the Sandwich Islanders are from the ' ' Honolulu 
 Gazette," and from Mr. Coan,
 
 218 THE DESCENT OF MAN. 
 
 interesting circumstance that the chief check to wild ani- 
 mals becoming domesticated, which implies the power of 
 their breeding freely when first captured, and one chief 
 check to wild men, when brought into contact with civil- 
 ization, surviving to form a civilized race, is the same, 
 namely, sterility from changed conditions of life. 
 
 Finally, although the gradual decrease and ultimate 
 extinction of the races of man is a highly complex 
 problem, depending on many causes which differ in 
 different places and at different times ; it is the same 
 problem as that presented by the extinction of one of 
 the higher animals of the fossil horse, for instance, which 
 disappeared from South America, soon afterward to be 
 replaced, within the same districts, by countless troups of 
 the Spanish horse. The New Zealander seems conscious of 
 this parallelism, for he compares his future fate with that 
 of the native rat now almost exterminated by the Euro- 
 pean rat. Though the difficulty is great to our imagi- 
 nation, and really great, if we wish to ascertain the precise 
 causes and their manner of action, it ought not to be so to 
 our reason, as long as we keep steadily in mind that the 
 increase of each species and each race is constantly checked 
 in various ways; so that if any new check, even a slight 
 one, be superadded, the race will surely decrease in number; 
 and decreasing numbers will sooner or later lead to extinc- 
 tion; the end, in most cases, being promptly determined 
 by the inroads of conquering tribes. 
 
 On the Formation of the Races of Man. In some cases 
 the crossing of distinct races has led to the formation of a 
 new race. The singular fact that the Europeans and Hin- 
 doos, who belong to the same Aryan stock and speak a, 
 language fundamentally the same, differ widely in appear- 
 ance, while Europeans differ but little from Jews, who 
 belong to the Semitic stock and speak quite another lan- 
 guage, has been accounted for by Broca,* through certain 
 Aryan branches having been largely crossed by indigenous 
 tribes during their wide diffusion. When two races in 
 close contact cross the first result is a heterogeneous mix- 
 ture; thus Mr. Hunter, in describing the Santali or hill- 
 
 *" On Anthropology," translation " Anthropolog. Review," Jan., 
 1868, p. 88.
 
 THE RAVES OF MAN. 219 
 
 tribes of India, says that hundreds of imperceptible grada- 
 tions may be traced " from the black, squat tribes of the 
 mountains to the tall olive-colored Brahman, with his intel- 
 lectual brow, calm eyes, and high but narrow head;" so 
 that it is necessary in courts of justice to ask the wit- 
 nesses whether they are Santalis or Hindoos.* Whether 
 a heterogeneous people, such as the inhabitants of some 
 of the Polynesian islands, formed by the crossing of two 
 distinct races, with few or no pure members left, would/ 
 ever become homogeneous, is not known from direct evi-i 
 dence. But as with our domesticated animals, a cross- 
 breed can certainly be fixed and made uniform by careful 
 selectionf in the course of a few generations, we may infer 
 that the free intercrossing of a heterogeneous mixture 
 during a long descent would supply the place of selection 
 and overcome any tendency to reversion ; so that the 
 crossed race would ultimately become homogeneous, 
 though it might not partake in an equal degree of the 
 characters of the two parent-races. 
 
 Of all the differences between the races of man, the color 
 of the skin is the most conspicuous and one of the best 
 marked. It was formerly thought that differences of this 
 kind could be accounted for by long exposure to 
 different climates ; but Pallas first showed that this 
 is not tenable and he has since been followed 
 by almost all anthropologists. \ This view has been 
 rejected chiefly because the distribution of the variously 
 colored races, most of whom must have long inhabited their 
 present homes, does not coincide with corresponding dif- 
 ferences of climate. Some little weight may be given to 
 such cases as that of the Dutch families, who, as we hear on 
 excellent authority,! have not undergone the least change 
 of color after residing for three centuries in S. Africa. 
 An argument on the same side may likewise be drawn 
 
 * " The Annals of Rural Bengal," 1868, p. 134. 
 
 f "The Variation of Animals and Plants under Domestication," 
 vol. ii, p. 95. 
 
 \ Pallas, "Act. Acad. St. Petersburg," 1780, part ii, p. 69. He 
 was followed by Rudolphi, in his " Beytrage zur Anthropologie," 
 1812. An excellent summary of the evidence is given by Godron, 
 " De 1'Espece," 1859, vol. ii, p. 246, etc. 
 
 Sir Andrew Smith, as quoted by Knox, " Races of Man," I860, 
 p. 473,
 
 220 THE DESCENT OF MAN. 
 
 from the uniform appearance in various parts of the world 
 of gypsies and Jews, though the uniformity of the latter 
 has been somewhat exaggerated.* A very damp or a very 
 dry atmosphere has been supposed to be more influential in 
 modifying the color of the skin than mere heat; but as 
 D'Orbigny in South America, and Livingstone in Africa, 
 arrived at diametrically opposite conclusions with respect to 
 dampness and dryness, any conclusion on this head must 
 be considered as very doubtful, f 
 
 Various facts, which I have given elsewhere, prove that 
 the color of the skin and hair is sometimes correlated in a 
 surprising manner with a complete immunity from the 
 action of certain vegetable poisons, and from the attacks 
 of certain parasites. Hence it occurred to me, that 
 negroes and other dark races might have acquired their 
 dark tints by the darker individuals escaping from the 
 deadly influence of the miasma of their native countries, 
 during a long series of generations. 
 
 I afterward found that this same idea had long ago 
 occurred to Dr. Wells. J It has long been known that 
 negroes, and even mulattoes are almost completely exempt 
 from the yellow fever, so destructive in tropical America. 
 They likewise escape to a large extent the fatal intermit- 
 tent" fevers that prevail along at least 2,600 miles of the 
 shores of Africa, and which annually cause one-fifth of the 
 white settlers to die and another fifth to return home 
 invalided. || This immunity in the negro seems to be partly 
 inherent, depending on some unknown peculiarity of con- 
 stitution and partly the result of acclimatization. PouchetT 
 states that the negro regiments recruited near the Soudan 
 
 *See De Quatrefages on this head, "Revue des Cours Scien- 
 tifiques," Oct. 17, 1868, p. 731. 
 
 | Livingstone's "Travels and Researches in S. Africa," 1857, pp. 
 338, 339. D'Orbigny, as quoted by Godron, " De 1'Espece," vol. ii, 
 p. 2C6. 
 
 \ See a paper read before the Royal Soc. in 1813 and published in 
 his Essays in 1818. I have given an account of Dr. Wells' views in 
 the Historical Sketch (p. 16) to my " Origin of Species." Various 
 cases of color correlated with constitutional peculiarities are given in 
 jny " Variation of Animals under Domestication," vol. ii, pp. 227,335. 
 
 See, for instance, Nott and Gliddon, " Types of Mankind," p. 68, 
 
 J Maj. Tulloch, in a paper read before the Statistical Society, April 
 80, 1840, and given in the "Athenaeum," 1840, p. 353. 
 
 ^[" The Plurality of the H.m.an Race " (tranala.U 1864, r 60,
 
 THE RACES OF MAN. 221 
 
 an<? borrowed from the Viceroy of Egypt for the Mexican 
 war escaped the yellow fever almost equally with the 
 negroes originally brought from various parts of Africa and 
 accustomed to the climate of the West Indies. That 
 acclimatization plays a part is shown hy the many cases in 
 which negroes have become somewhat liable to tropical 
 fevers, after having resided for some time in a colder 
 climate.* The nature of the climate under which the 
 white races have long resided, likewise has some influence 
 on them; for during the fearful epidemic of yellow fever 
 iii Demerara during 1837 Dr. Blair found that the death- 
 rate of the immigrants was proportional to the latitude of 
 the country whence they had come. With the negro the 
 immunity, as far as it is the result of acclimatization, 
 implies exposure during a prodigious length of time; for 
 the aborigines of tropical America who have resided there 
 from time immemorial are not exempt from yellow fever; 
 and the Rev. H. B. Tristram states that there are districts 
 in Northern Africa which the native inhabitants are com- 
 pelled annually to leave, though the negroes can remain 
 with safety. 
 
 That the immunity of the negro is in any degree corre- 
 lated with the color of his skin is a mere conjecture; it 
 may be correlated with some difference in his blood, nerv- 
 ous system or other tissues. Nevertheless, from the facts 
 above alluded to and from some connection apparently ex- 
 isting between complexion and a tendency to consumption, 
 the conjecture seemed to me not improbable. Conse- 
 quently I endeavored, with but little success,! to ascertain 
 
 * Quatrefages, " Unite de 1'Espece Huraaine," 1861, p. 205. Waitz, 
 "Introduct. to Anthropology," translat., vol. i, 1863, p. 124. Liv- 
 ingstone gives analogous cases in his " Travels." 
 
 f In the spring of 1862 I obtained permission from the Director- 
 General of the Medical Department of the Array to transmit to the 
 surgeons of the various regiments on foreign service a blank table, 
 with the following appended remarks, but I have received no 
 returns: "As several well-marked cases have been recorded with 
 our domestic animals of a relation between the color of the dermal 
 appendages and the constitution; and it being notorious that there is 
 some limited degree of relation between the color of the races of man 
 and the climate inhabited by them; the following investigation seems 
 worth consideration. Namely, whether there is any relation in Euro- 
 peans between the color of their hair and their liability to the diseases 
 of tropical countries. If the surgeons of the several regiments, when 
 stationed in unhealthy tropical districts, would be so good as first to
 
 222 THE DESCENT OF MAN. 
 
 how far it holds good. The late Dr. Daniell, who had 
 long lived on the west coast of Africa, told me that he did 
 not believe in any such relation. He was himself unusually 
 fair and had withstood the climate in a wonderful manner. 
 When he first arrived as a boy on the coast an old and ex- 
 perienced negro chief predicted from his appearance that 
 this would prove the case. Dr. Nicholson, of Antigua, 
 after having attended to this subject, writes to me that 
 dark-colored Europeans escape the yellow fever more than 
 those that are light colored. Mr. J. M. Harris altogether 
 denies that Europeans with dark hair withstand a hot cli- 
 mate better than other men; on the contrary, experience 
 has taught him in making a selection of men for service on 
 the coast of Africa to choose those with red hair.* As far, 
 therefore, as these slight indications go, there seems no 
 foundation for the hypothesis that blackness has resulted 
 from the darker and darker individuals having survived 
 better during long exposure to fever-generating miasma. 
 Dr. Sharpe remarks, f that a tropical sun, which burns 
 
 count, as a standard of comparison, how many men, in the force 
 whence the sick are drawn, have dark and light-colored hair and 
 hair of intermediate or doubtful tints; and if a similar account were 
 kept by the same medical gentlemen of all the men who suffered 
 from malarious and yellow fevers, or from dysentery, it would soon 
 be apparent, after some thousand cases had been tabulated, whether 
 there exists any relation between the color of the hair and constitu- 
 tional liability to tropical diseases. Perhaps no such relation would 
 be discovered, but the investigation is well worth making. In case 
 any positive result were obtained it might be of some practical use 
 in selecting men for any particular service. Theoretically the result 
 would be of high interest, as indicating one means by which a race 
 of men inhabiting from a remote period an unhealthy tropical cli- 
 mate, might have become dark-colored by the better preservation of 
 dark-haired or dark-complexioned individuals during a long succes- 
 sion of generations." 
 
 "Anthropological Review," Jan., 1866, p. 21. Dr. Sharpe also 
 says, with respect to India (" Man a Special Creation," 1873, p. 118), 
 " that it has been noticed by some medical officers that Europeans 
 with light hair and florid complexions suffer less from diseases of 
 tropical countries than persons with dark hair and sallow complex- 
 ions; and, so far as I know, there appear to be good grounds for 
 this remark." On the other hand, Mr. Heddle, of Sierra Leone, 
 " who has had more clerks killed under him than any other man," 
 by the climate of the West African Coast (W. Reade, "African 
 Sketch Book," vol. ii, p. 522), holds a directly opposite view, as does. 
 Capt. Burton. 
 
 f "Man a Special Creation," 1873, p. 119.
 
 THE RACES OF MAN. 223 
 
 and blisters a white skin, does not injure a black one at all; 
 and, as he adds, this is not due to habit in the individual, 
 for children only six or eight months old are often carried 
 about naked, and are not affected. I have been assured by 
 a medical man that some years ago during each summer, 
 but not during the winter, his hands became marKed with 
 light brown patches, like, although larger than freckles, 
 and that these patches were never affected by sun-burning, 
 while the white parts of his skin have on several occasions 
 been much inflamed and blistered. With the lower ani- 
 mals there is, also, a constitutional difference in liability to 
 the action of the sun between those parts of the skin 
 clothed with white hair and other parts.* Whether the 
 saving of the skin from being thus burned is of sufficient 
 importance to account for a dark tint having been gradually 
 acquired by man through natural selection I am unable to 
 judge. If it be so, we should have to assume that the 
 natives of tropical America have lived there for a much 
 shoi*ter time than the negroes in Africa, or the Papuans in 
 the southern parts of the Malay Archipelago, just as the 
 lighter-colored Hindoos have resided in India for a shorter 
 time than the darker aborigines of the central and southern 
 parts of the peninsula. 
 
 Although with our present knowledge we cannot account 
 for the differences of color in the races of man, through 
 any advantage thus gained, or from the direct action of 
 climate; yet we must not quite ignore the latter agency, 
 for there is good reason to believe that some inherited effect 
 is thus produced, f 
 
 We have seen in the second chapter that the conditions 
 of life affect the development of the bodily frame in a 
 direct manner, and that the effects are transmitted. Thus, 
 as is generally admitted, the European settlers in the 
 United States undergo a slight but extraordinary rapid 
 
 * " Variation of Animals and Plants under Domestication," vol. ii, 
 pp. 336, 337. 
 
 f See, for instance, Quatrefages (" Revue des Cours Scientifiques," 
 Oct. 10, 1868, p. 724) on the effects of residence in Abyssinia and 
 Arabia, and other analogous cases. Dr. Rolle (" Der Menscli, seine 
 Abstammung," etc., 1865, s. 99) states, on the authority of Khanikof, 
 that the greater number of German families settled in Georgia have 
 acquired in the course of two generations dark hair and eyes. Mr. 
 D. Forbes informs me that the Quichuas in the Andes vary greatly in 
 color, according to the position of the valleys inhabited by them.
 
 224: THE DESCENT OF MAN. 
 
 change of appearance. Their bodies and limbs become 
 elongated; and I hear from Col. Bernys that during the 
 late war in the United States, good evidence was afforded 
 of this fact by the ridiculous appearance presented by the 
 German regiments when dressed in ready-made clothes 
 manufactured for the American market, and which were 
 much too long for the men in every way. There is, also, a 
 3onsiderable body of evidence showing that in the Southern 
 States the house slaves of the third generation present a 
 markedly different appearance from the field slaves.* 
 
 If, however, we look to the races of man as distributed 
 over the world we must infer that their characteristic dif- 
 ferences cannot be accounted for by the direct action of 
 different conditions of life, even after exposure to them for 
 an enormous period of time. The Esquimaux live exclu- 
 sively on animal food; they are clothed in thick fur, and 
 are exposed to intense cold and to prolonged darkness^ yet 
 they do not differ in any extreme degree from the inhabit- 
 ants of Southern China, who live entirely on vegetable 
 food and are exposed almost naked to a hot, glaring cli- 
 mate. The unclothed Fuegians live on the marine pro- 
 ductions of their inhospitable shores ; the Botocudos of 
 Brazil wander about the hot forests of the interior and live 
 chiefly on vegetable productions; yet these tribes resemble 
 each other so closely that the Fuegians on board the 
 " Beagle " were mistaken by some Brazilians for Botocudos. 
 The Botocudos again, as well as the other inhabitants of 
 tropical America, are wholly different from the negroes 
 who inhabit the opposite shores of the Atlantic, are ex- 
 posed to a nearly similar climate and follow nearly the 
 same habits of life. 
 
 Nor can the differences between the races of man be ac- 
 counted for by the inherited effects of the increased 01 
 decreased use of parts except to a quite insignificant degree. 
 Men who habitually live in canoes may have their legs 
 somewhat stunted; those who inhabit lofty regions may 
 have their chests enlarged; and those who constantly use 
 certain sense organs may have the cavities in which they 
 are lodged somewhat increased in size, and their features 
 consequently a little modified. With civilized nations the 
 
 *Harlan, "Medical Researches," p. 532. Quatrefages ("Unite de 
 1'Espece Humaine," 1861, p. 128) lias collected much evidence on thia 
 head.
 
 THE RACES OF MAN, 225 
 
 reduced size of the jaws from lessened use the habitual 
 play of different muscles serving to express different emo- 
 tions and the increased size of the brain from greater 
 intellectual activity have together produced a considerable 
 effect on their general appearance when compared with 
 savages. * Increased bodily stature, without any corre- 
 sponding increase in the size "of the brain, may (judging 
 from the previously adduced case of rabbits), have given 
 to some races an elongated skull of the dolichocephalic 
 type. 
 
 " Lastly, the little understood principle of correlated de- 
 velopment has sometimes come into action, as in the case 
 of great muscular development and strongly projecting 
 supra-orbital ridges. The color of the skin and hair are 
 plainly correlated, as is the texture of the hair with its 
 color in the Mandans of North America, f The color also 
 of the skin and the odor emitted by it are likewise in some 
 manner connected. With the breeds of sheep the number 
 of hairs within a given space and the number of the ex- 
 cretory pores are related. J If we may judge from the 
 analogy of our domesticated animals, many modifications 
 of structure in man probably come under this principle 
 of correlated development. 
 
 "We have now seen that the external characteristic differ- 
 ences between the races of man cannot be accounted for in 
 a satisfactory manner by the direct action of the conditions 
 of life, nor by the effects of the continued use of parts, 
 nor through the principle of correlation. We are there- 
 fore led to inquire whether slight individual differences, to 
 which man is eminently liable, may not have been pre- 
 served and augmented during a long series of generations 
 through natural selection. But here we are at once met 
 
 *See Prof. Schaaffhausen, translat., in "Anthropological Review," 
 Oct., 1868, p. 429. 
 
 fMr. Catlin states (" North American Indians," 3d edit., 1842, vol. 
 i, p. 49) that in the whole tribe of the Mandans, about one in ten or 
 twelve of the members, of all ages and both sexes, have bright sil- 
 very gray_hair, which is hereditary. Now this hair is as coarse and 
 harsh as that of a horse's mane, while the hair of other colors is fine 
 and soft. 
 
 JOn the odor of the skin, Godron, " Stir I'Espece," torn ii, p. 217. 
 On the pores in the skin, Dr. Wilckens, " Die Aufgaben der Lun-i- 
 wirth. Zootechnik," 1869, s. 7.
 
 226 THE DESCENT OF MAN. 
 
 by the objection that beneficial variations alone can be 
 thus preserved; and as far as we are enabled to judge, 
 although always liable to err on this head, none of the dif- 
 ferences between the races of man are of any direct or 
 special service to him. The intellectual and moral or 
 social faculties must of course be excepted from this 
 remark. The great variability of all the external differ- 
 ences between the races of man, likewise indicates that 
 they cannot be of much importance; for if important, they 
 would long ago have been either fixed and preserved or 
 eliminated. In this respect man resembles those forms, 
 called by naturalists protean or polymorphic, which have 
 remained extremely variable, owing, as it seems, to such 
 variations being of an indifferent nature, and to their 
 having thus escaped the action of natural selection. 
 
 We have thus far been baffled in all our attempts to 
 account for the differences between the races of man ; but 
 there remains one important agency, namely Sexual Selec- 
 tion, which appears to have acted powerfully on man, as 
 on many other animals. I do not intend to assert that 
 sexual selection will account for all the differences between 
 the races. An unexplained residuum is left, about which 
 we can only say, in our ignorance, that as individuals are 
 continually born with, for instance, heads a little rounder 
 or narrower, and with noses a little longer or shorter, such 
 slight differences might become fixed and uniform, if the 
 unknown agencies which induced them were to act in a 
 more constant manner, aided by long-continued inter- 
 crossing. Such variations come under the provisional 
 class, alluded to in our second chapter, which for the want 
 of a better term are often called spontaneous. Nor do I 
 pretend that the effects of sexual selection can be indicated 
 with scientific precision ; but it can be shown that it 
 would be an inexplicable fact if man had not been modi- 
 fied by this agency, which appears to have acted power- 
 fully on innumerable animals. It can further be shown 
 that the differences between the races of man, as in color, 
 hairiness, form of features, etc., are of a kind which might 
 have been expected to come under the influence of sexual 
 selection. But in order to treat this subject properly, I 
 have found it necessary to pass the whole animal kingdom 
 in review. I have therefore devoted to it Part II of this 
 work. At the close I shall return to man, and, after
 
 THE RACES OF MAN. 227 
 
 attempting to show how far he has heen modified through 
 sexual selection, will give a brief summary of the chapters 
 in Part I. 
 
 NOTE ON THE RESEMBLANCES AND DIFFERENCES IN THE STRUCTURE 
 AND THE DEVELOPMENT OF THE BRAIN IN MAN AND APES. 
 BY PROF. HUXLEY, F.R.S. 
 
 The controversy respecting the nature and the extent of the differ- 
 ences in the structure of the brain in man and the apes, which arose 
 some fifteen years ago, has not yet come to an end, though the sub. 
 ject matter of the dispute is, at present, totally different from what 
 it was formerly. It was originally asserted and reasserted, with sin 
 gular pertinacity, that the brain of all the apes, even the highest, 
 differs from that of man, in the absence of such conspicuous struct- 
 ures as the posterior lobes of the cerebral hemispheres, with the pos- 
 terior cornu of the lateral ventricle and the hippocampus minor, con- 
 tained in those lobes, which are so obvious in man. 
 
 But the truth that the three structures in question are as well 
 developed in apes as in human brains, or even better; and that it is 
 characteristic of all the Primates (if we exclude the Lemurs) to have 
 these parts well developed, stands at present on as secure a basis as 
 any proposition in comparative anatomy. Moreover, it is admitted 
 by every one of the long series of anatomists who, of late years, have 
 paid special attention to the arrangement of the complicated sulci 
 and gyri which appear upon the surface of the cerebral hemispheres 
 in man and the higher apes, that they are disposed after the very 
 same pattern in him as in them. Every principal gyrus and sulcus 
 of a chimpanzee's brain is clearly represented in that of a man, so 
 that the terminology which applies to the one answers for the other. 
 On this point there is no difference of opinion. Some years since, 
 Prof. Bischoff published a memoir* on the cerebral convolutions of 
 man and apes; and as the purpose of my learned colleague was cer- 
 tainly not to diminish the value of the differences between apes and 
 men in this respect, I am glad to make a citation from him. 
 
 " That the apes, and especially the orang, chimpanzee and gorilla, 
 come very close to man in their organization, much nearer than to 
 any other animal, is a well-known fact, disputed by nobody. Look- 
 ing at the matter from the point of view of organization alone, no 
 one probably would ever have disputed the view of Linnaeus, that 
 man should be placed, merely as a peculiar species, at the head of 
 the mammalia and of those apes. Both show, in all their organs, so 
 close an affinity that the nmst exact anatomical investigation is needed 
 in order to demonstrate those differences which really exist. So it is 
 with the brains. The brains of man, the orang, the chimpanzee, the 
 gorilla, in spite of all the important differences which they present, 
 come very'close to one another " (1. c., p. 101). 
 
 There remains, then, no dispute as to the resemblance in funda- 
 mental characters, between the ape's brain and man's; nor any as to 
 
 ""Die Grosshira-Windungen des Menschen;" *' Abhandlungen der K. 
 Bayerischen Aiademje," Bd. x. 186a
 
 228 THE DESCENT OF MAN. 
 
 the wonderfully close similarity between the chimpanzee, orang and 
 man, in even the details of the arrangement of the gyri and sulci of 
 the cerebral hemispheres. Nor, turning to the differences between 
 the brains of the highest apes and that of man, is there any serious 
 question as to the nature and extent of these differences. It is ad- 
 mitted that the man's cerebral hemispheres are absolutely and rela- 
 tively larger than those of the orang and chimpanzee; that his frontal 
 lobes are less excavated by the upward protrusion of the roof of the 
 orbits; that his gyri and s'ulci are, as a rule, less symmetrically dis- 
 posed, and present a greater number of secondary plications. And it 
 is admitted that, as a rule, in man, the teniporo-occipital or " exter- 
 nal perpendicular " fissure, which is usually so strongly marked a 
 feature of the ape's brain is but faintly marked. But it is also clear, 
 that none of these differences constitutes a sharp demarcation between 
 the man's and the ape's brain. In respect to the external perpendic- 
 ular fissure of Gratiolet, in the human brain for instance, Prof. Turner 
 remarks : * 
 
 " In some brains it appears simply as an indentation of the margin 
 of the hemisphere, but in others it extends for some distance more or 
 less transversely outward. I saw it in the right hemisphere of a 
 female brain pass more than two inches outward; and on another 
 specimen, also the right hemisphere, it proceeded for four-tenths of 
 an inch outward, and then extended downward as far as the lower 
 margin of the outer surface of the hemisphere. The imperfect defi- 
 nition of this fissure in the majority of human brains, as compared 
 with its remarkable distinctness in the brain of most Quadrumana, is 
 owing to the presence in the former of certain superficial, well- 
 marked, secondary convolutions which bridge it over and connect the 
 parietal with the occipital lobe. The closer the first of these bridg- 
 ing gyri lies to the longitudinal fissure the shorter is the external 
 parieto-occipital fissure " (1. c., p. 12). 
 
 The obliteration of the external perpendicular fissure of Gratiolet, 
 therefore, is not a constant character of the human brain. On the 
 other hand, its full development is not a constant character of the 
 higher ape's brain. For, in the chimpanzee, the more or less exten- 
 sive obliteration of the external perpendicular sulcus by " bridging 
 convolutions," on one side or the other, has been noted over and over 
 again by Prof. Rolleston, Mr. Marshall, M. Broca and Prof. Turner. 
 At the conclusion of a special paper on this subject the latter writes :f 
 
 " The three specimens of the brain of a chimpanzee just described, 
 prove that the generalization which Gratiolet has attempted to draw 
 of the complete absence of the first connecting convolution and the 
 concealment of the second, as essentially characteristic features in the 
 brain of this animal, is by no means universally applicable. In only 
 one specimen did the brain, in these particulars, follow the law 
 which Gratiolet has expressed. As regards the presence of the 
 superior bridging convolution, I am inclined to think that it has 
 existed in one hemisphere, at least, in a majority of the brains of this 
 
 * " Convolutions of the Human Cerebrum Topographically Considered," 
 1806, p. 12. 
 
 t Notes more especially on the bridging convolutions in the brain of the 
 chimpanzee, " Proceedings of the Royal Society of Edinburgh," 1865-66.
 
 THE RACES OF MAN. 229 
 
 animal which have, up to this time, been figured or described. The 
 superficial position of the second bridging convolution is evidently 
 less frequent, and has as yet, I believe, only been seen in the brain 
 (A) recorded in this communication. The asymmetrical arrangement 
 in the convolutions of the two hemispheres, which previous observ- 
 ers have referred to in their descriptions, is also well illustrated in 
 these specimens " (pp. 8, 9). 
 
 Even were the presence of the temporo-occipital, or external per- 
 pendicular, sulcus, a mark of distinction between the higher apes 
 and man, the value of such a distinctive character would be ren- 
 dered very doubtful by the structure of the brain in the Platyrrhine 
 apes. In fact, while the temporo-occipital is one of the most con- 
 stant of sulci in the Catarrhine, or Old World, apes, it is never very 
 strongly developed in the New World apes; it is absent in the smaller 
 Platyrrhini; rudimentary in Pithecia ;* and more or less obliterated 
 
 by bridging convolutions in Ateles. 
 A character w 
 
 which is thus variable within the limits of a single 
 group can have no great taxonomic value. 
 
 It is further established that the degree of asymmetry of the con- 
 volution of the two sides in the human brain is subject to much indi- 
 vidual variation; and that, in those individuals of the Bushman 
 race who have been examined, the gyri and sulci of the two hemis- 
 pheres are considerably less complicated and more symmetrical than 
 in the European brain, while, in some individuals of the chimpanzee, 
 their complexity and asymmetry become notable. This is particu- 
 larly the case in the brain of a young male chimpanzee figured by M. 
 Broca ("L'ordre des Primates," p. 165, fig. 11). 
 
 Again, as respects the question of absolute size, it is established 
 that the difference between the largest and the smallest healthy 
 human brain is greater than the difference between the smallest 
 healthy human brain and the largest chimpanzee's or orang's brain. 
 
 Moreover, there is one circumstance in which the orang's and the 
 chimpanzee's brains resemble man's, but in which they differ from the 
 lower apes, and that is the presence of two corpora candicantia the 
 Cynomorpha having but one. 
 
 In view of these facts 1 do not hesitate in this year, 1874, to 
 repeat and insist upon the proposition which I enunciated in 1863:f 
 
 " So far as cerebral structure goes, therefore, it is clear that man 
 differs less from the chimpanzee or the orang than these do even 
 from the monkeys, and that the difference between the brain of the 
 chimpanzee and of man is almost insignificant when compared with 
 that between the chimpanzee brain and that of a Lemur." 
 
 In the paper to which I have referred, Prof. Bischoff does not 
 deny the second part of this statement, but he first makes the irrele- 
 vant remark that it is not wonderful if the brains of an orang and a 
 Lemur are very different; and secondly, goes on to assert that, " If 
 we successively compare the brain of a man with that of an orang; 
 the brain of this with that of a chimpanzee; of this with that of a 
 gorilla, and so on of a Hylobates, Semnopithecus, Cynocephalus, Cer- 
 
 * Flower "On the Anatomy of Pithtcla Jfwiac/iw," " Proceedings of the 
 Zoological Society," 1862. 
 
 + " Man's Place in Nature," p. 108,
 
 230 THE DESCENT OF MAN. 
 
 copithecun, Macacus, Cebus, CattitJirix, Lemur, Stenops, Hapale, we 
 shall not meet with a greater, or even as great, a break in the degree 
 of development of the convolutions as we find between the brain of 
 a man and that of an orang or chimpanzee." 
 
 To which I reply, firstly, that whether this assertion be true or 
 false, it has nothing whatever to do with the proposition enunciated 
 in "Man's Place in Nature," which refers not to the development of 
 the convolutions alone, but to the structure of the whole brain. If 
 Prof. Bischoff had taken the trouble to refer to p. 96 of the work he 
 criticises, in fact, he would have found the following passage: "And 
 it is a remarkable circumstance that though, so far as our present 
 knowledge extends, there is one true structural break in the series of 
 forms of Simian brains, this hiatus does not lie between man and the 
 manlike apes, but between the lower and the lowest Simians, or in 
 other words, between the Old and New World apes and monkeys and 
 the Lemurs. Every Lemur which has yet been examined, in fact, 
 has its cerebellum partially visible from above; and its posterior lobe, 
 with the contained posterior cornu and hippocampus minor, more or 
 less rudimentary. Every marmoset, American monkey, Old World 
 monkey, baboon, or manlike ape, on the contrary, has its cerebellum 
 entirely hidden, posteriorly, by the cerebral lobes, and possesses a 
 large posterior cornu with a well-developed hippocampus minor." 
 
 This statement was a strictly accurate account of what was known 
 when it was made; and it does not appear to me to be more than 
 apparently weakened by the subsequent discovery of the relatively 
 small development of the posterior lobes in the Siamang and in the 
 Howling monkey. Notwithstanding the exceptional brevity of the 
 posterior lobes in these two species, no one will pretend that their 
 brains in the slightest degree approach those of the Lemurs. And 
 if, instead of putting Hapale out of its natural place, as Prof. Bischoff 
 most unaccountably does, we write the series of animals he has 
 chosen to mention as follows : Homo, Pithecus, Troglodytes, Hylo- 
 bates, Semnopithecus, Oynocephaliis, Cercopithecus, Macacus, Cebus, 
 CaUithrix, Hapale, Lemur, Stenops. I venture to reaffirm that the 
 great break in this series lies between Hapale and Lemur, and that 
 this break is considerably greater than that between any other two 
 terms of that series. Prof. Bischoff ignores the fact that long before 
 he wrote Gratiolet had suggested the separation of the Lemurs from 
 the other Primates on the very ground of the difference in their cere- 
 bral characters ; and that Prof. Flower had made the following 
 observations in the course of his description of the brain of the Javan 
 Loris : * 
 
 "And it is especially remarkable that, in the development of the 
 posterior lobes, there is no approximation to the Lemurine, short- 
 hemisphered brain, in those monkeys which are commonly supposed 
 to approach this family in other res'pects, viz. , the lower members of 
 the Platyrrhine group." 
 
 So far as the structure of the adult brain is concerned, then, the 
 very considerable additions to our knowledge, which have been made 
 by the researches of so many investigators during the past ten years 
 fully justify the statement which I made in 1863. But it has been 
 
 * " Transactions of the Zoological Society," vol. v, 1862.
 
 THE RACES OF MAN. 231 
 
 said that, admitting the similarity between the adult brains of man 
 and apes, they are, nevertheless, in reality, widely different, because 
 they exhibit fundamental differences in the mode of their develop- 
 ment. No one would be more ready than I to admit the force of this 
 argument, if such fundamental differences of development really 
 exist. But I deny that they do exist. On the contrary, there is a 
 fundamental agreement in the development of the brain in men and 
 apes. 
 
 Gratiolet originated the statement that there is a fundamental dif- 
 ference in the development of the brains of apes and that of man 
 Jbonsisting in this; that in the apes the sulci which first make their 
 appearance are situated on the posterior region of the cerebral hem- 
 ispheres, while in the human foatus the sulci firpt become visible on 
 the frontal lobes.* 
 
 This general statement is based upon two observations, the one "of 
 a Gibbon almost ready to be born, in which the posterior gyri were 
 "well developed," while those of the frontal lobes were "hardly 
 indicated"! (1. c., p. 89), and the other of a human foetus at the 
 22d or 23d week of uterogestation, in which Gratiolet notes that the 
 insula was uncovered, but that nevertheless "des incisures sement 
 de lobe anterieur, une scissure peu profoude indique la separation du 
 lobe occipital, tres-reduit, d'ailleurs des cette epoque. Le reste de la 
 surface cerebrale est encore absolument lisse." 
 
 Three views of this brain are given in plate 2, figs. 1, 2, 3, of the 
 work cited, showing the upper, lateral and inferior views of the 
 hemispheres, but not the inner view. It is worthy of note that the 
 figure by no means bears out Gratiolet's description, inasmuch as the 
 fissure (antero- temporal) on the posterior half of the face of the hem- 
 isphere is more marked than any of those vaguely indicated in the 
 anterior half. If the figure is correct, it in no way justifies Gratio- 
 let's conclusion: "II y a done entre ces cerveaux [those of a Calli- 
 thrix and of a Gibbon] et celui du f cetus humain une difference fonda- 
 mental. Chez celui-ci, longternps avant que les plis temporaux. 
 apparaissent, les plis frontaux essayentd'exister." 
 
 Since Gratiolet's time, however, the development of the gyri and 
 
 * " Chez tous les singes, les plis posterieurs se developpent les premiers ; 
 les plis anterieurs se developpent plus tard, aussi la vertebre occipitale et la 
 panetale sont-elles relativement tresgrandes chez le foetus. L'Homme pres- 
 ente une exception remarquable quant a 1'epoque de 1'apparition des plis 
 frontaux, qui sont les premiers indiques ; mais le developpement general du 
 lobe frontal, envisage seulement par rapport a son volume, suit les memes lois 
 que dans les singes ;" Gratiolet, t{ Memoire sur les plis cerebraux de 1'Homme 
 et des Primates," p. 39, Tab. iv, fig. 3. 
 
 t Gratiolet's words are (1. c., p. 39): " Dans le foetus dont il s'agit les plis 
 cerebraux posterieurs sont bien developpes, tandis que les plis du lobe frontal 
 sont a peine indiques." The figure, however (PI. iv, fig. 3), shows the fissure 
 of Rolando, and one of the frontal sulci, plainly enough. Nevertheless, M. 
 Alix, in his " Notice sur les travaux anthropologiques de Gratiolet " (Mem. de 
 la Societe d'Anthropologie de Paris," 1868, p. >>), writes thus: "Gratiolet a 
 eu entre les mains le cerveau d'un foetus de Gibbon, singe eminemment supe- 
 rieur, et tellement rapproche de 1'orang, que des naturalistes tres-competents 
 1'ont range parmi les anthropoides. M. Huxley, par exemple, n'hesite pas sur 
 ce point. En bien, c'est sur le cerveau d'un foetus de Gibbon que Gratiolet a 
 vu " les oil-convolutions du lobe tempoio-sphenoidal deja dereloppees torsqu'U n'exist- 
 ent pas encorj de plis sur le lobe frontal. II etait done bien autorise a dire que, 
 chez 1'Homme les circonvolutions apparaissent d'a en w, tandis que chez lea 
 singes elles se develoooent d'* aJi <V
 
 232 THE DESCENT OF MAN. 
 
 sulci of the brain has been made the subject of renewed investigation 
 by Scliinidt, Bischoff, Pansch,* and more particularly by Ecker, f 
 whose work is not only the latest, but by far the most complete 
 memoir on the subject. 
 
 The final results of their inquiries may be summed up as follows: 
 
 1. In the human foetus, the sylvian fissure is formed in the course 
 of the third month of uterogestation. In this, and in the fourth 
 month, the cerebral hemispheres are smooth and rounded (with the 
 exception of the sylvian depression), and they project backward far 
 beyond the cerebellum. 
 
 2. The sulci, properly so called, begin to appear in the interval 
 between the end of the fourth and the beginning of the sixth month 
 of foetal life, but Ecker is careful to point out that, not only the 
 time, but the order, of their appearance is subject to considerable 
 individual variation. In no case, however, are either the frontal or 
 the temporal sulci the earliest. 
 
 The first which appears, in fact, lies on the inner face of the hem- 
 isphere (whence doubtless Gratiolet, who does not seem to have 
 examined that face in his foetus, overlooked it), and is either the 
 internal perpendicular (occipito-parietal), or the calcarine sulcus, 
 these two being close together and eventually running into one 
 another. As a rule the occipito-parietal is the earlier of the two. 
 
 3. At the latter part of this period, another sulcus, the " posterio- 
 parietal," or " Fissure of Rolando," is developed, and it is followed, 
 in the course of the sixth month by the other principal sulci of the 
 frontal, parietal, temporal and occipital lobes. There is, however, 
 no clear evidence that one of these constantly appears before the 
 other; and it is remarkable that, in the brain at the period described 
 and figured by Ecker (1. c., p. 212-213, Taf. II, figs. 1, 2, 3, 4), the 
 antero-temporal sulcus (scissure parallelc) so characteristic of the ape's 
 brain, is as well if not better developed than the fissure of Rolando, 
 and is much more marked than the proper frontal sulci. 
 
 Taking the facts as they now stand, it appears to me that the 
 order of the appearance of the sulci and gyri in the foetal human 
 brain is in perfect harmony with the general doctrine of evolution, 
 and with the view that man has been evolved from some ape-like 
 form; though there can be no doubt that that form was, in many 
 respects, different from any member of the Primates now living. 
 
 Von Baer taught us, half a century ago, that, in the course of 
 their development, allied animals put on at first, the characters of 
 the greater groups to which they belong, and, by degrees, assume 
 those which restrict them within the limits of their family, genus, 
 and species; and he proved, at the same time, that no developmental 
 stage of a higher animal is precisely similar to the adult condition of 
 any lower animal. It is quite correct to say that a frog passes through, 
 the condition of a fish, inasmuch as at one period of its life the tad- 
 pole has all the characters of a fish, and if it went no further would 
 
 *"Ueber die typische Anordnung derFurchen und Windunpen auf den 
 Grosshirn-Hemisphareu des Menschen und der Affen." " Archiv. f ur Anthro 
 pologie," iii, 1868. 
 
 t " Zur Entwickelungs Geschichte der Furchen und Wimiunge i der Gross- 
 hirn-Hemispharen im Foetus des Menschen." " Archiv. fur Anthropologie,"
 
 THE RACES OF MAN. 233 
 
 have to be grouped among fishes. But it is equally true that a tad- 
 pole is very different from any known fish. 
 
 In like manner, the brain of a human fo3tus, at the fifth month, 
 may correctly be said to be, v not only the brain of an ape, but that of 
 an Arctopithecine or marmoset-like ape; for its hemispheres, with 
 their great posterior lobster, and with no sulci but the sylvian and 
 the calcarine, present the characteristics found only in the group of 
 the Arctopithecine Primates. But it is equally true, as Gratiolet 
 remarks, that in its widely open sylvian fissure it differs from the 
 brain of any actual marmoset. No doubt it would be much more 
 similar to the brain of an advanced foetus of a marmoset. But we 
 know nothing whatever of the development of the brain in the mar- 
 mosets. In the Platyrrhini proper, the only observation with which 
 I am acquainted is due to Pansch, who found in the brain of a foetal 
 Cebus Apella, in addition to the sylvian fissure and the deep calcarine 
 fissure, only a very shallow antero-temporal fissure (scissure parallele 
 of Gratiolet). 
 
 Now this fact, taken together with the circumstance that the 
 antero-temporal sulcus is present in such Platyrrhini as the Saimiri, 
 which present mere traces of sulci on the anterior half of the exterior 
 of the cerebral hemispheres, or none at all, undoubtedly, so far as it 
 goes, affords fair evidence in favor of Gratiolet's hypothesis, that the 
 posterior sulci appear before the anterior, in the brains of the 
 Platyrrhini. But it by no means follows that the rule which may 
 hold good for the Platyrrhini extends to the Catarrhini. We have 
 no information whatever respecting the development of the brain in 
 the Cynomorpha; and as regards the Anthropomorpha, nothing but 
 the account of the brain of the Gibbon, near birth, already referred 
 to. At the present moment there is not a shadow of evidence to show 
 that the sulci of a chimpanzee's or orang's brain do not appear in the 
 same order as a man's. 
 
 Gratiolet opens his preface with the aphorism : "II est dangereux 
 dans les sciences de conclure trop vite." I fear he must have for- 
 gotten this sound maxim by the time he had reached the discussion 
 of the differences between men and apes in the body of his work. No 
 doubt the excellent author of one of the most remarkable contribu- 
 tions to the just understanding of the mammalian brain which has 
 ever been made, would have been the first to admit the insufficiency 
 of his data had he lived to profit by the advance of inquiry. The 
 misfortune is that his conclusions have been employed by persons 
 incompetent to appreciate their foundation as arguments in favor of 
 obscurantism.* 
 
 But it is important to remark that, whether Gratiolet was right or 
 wrong in his hypothesis respecting the relative order of appearance 
 of the temporal and frontal sulci, the fact remains, that before either 
 temporal or frontal sulci appear, the fostal brain of man presents 
 characters which are found only in the lowest group of the Primates 
 (leaving ojit the Lemurs); and that this is exactly wliat we should 
 ex"pect to be the case if man has resulted from the gradual modifica- 
 tion of the same form as that from which the other Primates have 
 sprung. 
 
 * For example, M. 1'Abbe Lecomte in his terrible pamphlet, " Le Darwin- 
 ismo et Torigine de 1'Homme," 1873.
 
 254 THE DESCENT OF MAN. 
 
 PART II. 
 
 SEXUAL SELECTION. 
 
 CHAPTER VIII. 
 
 PRINCIPLES OF SEXUAL SELECTION. 
 
 Secondary sexual characters Sexual selection Manner of action- 
 Excess of males Polygamy The male alone generally modified 
 through sexual selection Eagerness of the male Variability of 
 the male Choice exerted by the female Sexual compared with 
 natural selection Inheritance, at corresponding periods of life, 
 at corresponding seasons of the year, and as limited by sex 
 Relations between the several forms of inheritance Causes why 
 one sex and the young are not modified through sexual selection 
 Supplement on the proportional numbers of the two sexes 
 throughout the animal kingdom The proportion of the sexes iu 
 relation to natural selection. 
 
 WITH animals which have their sexes separated, the 
 males necessarily differ from the females in their organs of 
 reproduction; and these are the primary sexual characters. 
 But the sexes often differ in what Hunter has called secondary 
 sexual characters, which are not directly connected with 
 the act of reproduction; for instance, the male possesses 
 certain organs of sense or locomotion, of which the female 
 is quite destitute, or has them more highly developed, in 
 order that he may readily find or reach her; or again the 
 male has special organs of prehension for holding her 
 securely. These latter organs, of infinitely diversified 
 kindSj graduate into those which are commonly ranked as 
 primary > and in some cases can hardly be distinguished 
 from them: we see instances of this in the complex append- 
 ages at the apex of the abdomen in male insects. Unless 
 indeed we confine the term " primary" to the reproductive
 
 SEXUAL SELECTION. 235 
 
 glands, it is scarcely possible to decide which ought to be 
 called primary and which secondary. 
 
 The female often differs from the male in having organs 
 for the nourishment or protection of her young, such as the 
 mammary glands of mammals and the abdominal sacks of 
 the marsupials. In some few cases also the male possesses 
 similar organs, which are wanting in the female, such as 
 receptacles for the ova in certain male fishes, and those 
 temporarily developed in certain male frogs. The females 
 of most bees are provided with a special apparatus for col- 
 lecting and carrying pollen, and their ovipositor is modified 
 into a sting for the defense of the larvae and the community. 
 Many similar cases could be given, but they do not here 
 concern us. There are, however, other sexual differences 
 quite unconnected with the primary reproductive organs, 
 and it is with these that we are more especially concerned, 
 such as the greater size, strength and pugnacity of the male, 
 his weapons of offense or means of defense against rivals, 
 his gaudy coloring and various ornaments, his power of song 
 and other such characters. 
 
 Besides the primary and secondary sexual differences, 
 such as the foregoing, the males and females of some 
 animals differ in structures related to different habits 
 of life, and not at all, or only indirectly, to the repro- 
 ductive functions. Thus the females of certain flies 
 (Culicidae and Tabanidas) are blood-suckers, while the 
 males, living on flowers, have mouths destitute of mandi- 
 bles.* The males of certain moths and of some crustaceans 
 (e. g. Tanais) have imperfect, closed mouths, and cannot 
 feed. The complemental males of certain Cirripedes live 
 like epiphytic plants either on the female or the hermaph- 
 rodite form, and are destitute of a mouth and of prehensile 
 limbs. In these cases it is the male which has been modi- 
 fied and has lost certain important organs which the 
 females possess. In other cases it is the female which has 
 lost such parts; for instance, the female glow-worm is des- 
 titute of wings, as also are many female moths, some of 
 which never leave their cocoons. Many female parasitic 
 crustaceans have lost their natatory legs. In some weevil- 
 
 *Westwood, "Modern Class of Insects," vol. ii, 1840, p. 541. 
 For the statement about Tanais, mentioned below, I am indebted to 
 Fritz Mtiller.
 
 236 THE DESCENT OF MAN. 
 
 beetles (Curculionidge) there is a great difference between 
 the male and the female in the length of the rostrum or 
 snout; * but the meaning of this and of many analogous 
 differences is not at all understood. Differences of structure 
 between the two sexes in relation to different habits of life 
 are generally confined to the lower animals; but with some 
 few birds the beak of the male differs from that of the 
 female. In the Huia of New Zealand the difference is 
 wonderfully great, and we hear from Dr. Buller f that the 
 male uses his strong beak in chiseling the larvse of insects 
 out of decayed wood, while the female probes the softer 
 parts with her far longer, much curved and pliant beak; 
 and thus they mutually aid each other. In most cases 
 differences of structure between the sexes are more or less 
 directly connected with the propagation of the species; thus 
 a female, which has to nourish a multitude of ova, requires 
 more food than the male, and consequently requires special 
 means for procuring it. A male animal, which lives for a 
 very short time, might lose its organs for procuring food 
 through disuse, without detriment; but he would retain his 
 locomotive organs in a perfect state, so that he might reach 
 the female. The female, on the other hand, might safely 
 lose her organs for flying, swimming, or walking, if she 
 gradually acquired habits which rendered such powers 
 
 We are, however, here concerned only with sexual selec- 
 tion. This depends on the advantage which certain indi- 
 viduals have over others of the same sex and species solely 
 in respect of reproduction. When, as in the cases above 
 mentioned, the two sexes differ in structure in relation to 
 different habits of life, they have no doubt been modified 
 through natural selection, and by inheritance limited to 
 one and the same sex. So again the primary sexual 
 organs, and those for nourishing or protecting the young, 
 come under the same influence; for those individuals which 
 generated or nourished their offspring best, would leave, 
 cceteris paribus, the greatest number to inherit their 
 superiority; while those which generated or nourished their 
 offspring badly would leave but few to inherit their weaker 
 powers. As the male has to find the female he requires 
 
 *Kirby and Spence, "Introduction to Entomology," vol. iii, 1826, 
 p. 309. 
 f " Birds of New Zealand," 1872, p. 66.
 
 SEXUAL SELECTION. 237 
 
 organs of sense and locomotion, but if these organs are 
 necessary for the other purposes of life, as is generally the 
 case, they will have been developed through natural selec- 
 tion. When the male has found the female he sometimes 
 absolutely requires prehensile organs to hold her; thus Dr. 
 Wallace informs me that the males of certain moths cannot 
 unite with the females if their tarsi or feet are broken. 
 The males of many oceanic crustaceans, when adult, have 
 their legs and antennae modified in an extraordinary 
 manner for the prehension of the female; hence we may 
 suspect that it is because these animals are washed about 
 by the waves of the open sea that they require these organs 
 in order to propagate their kind, and, if so, their develop- 
 ment has been the result of ordinary or natural selection. 
 Some animals extremely low in the scale have been modified 
 for this same purpose; thus the males of certain parasitic 
 worms, when fully grown, have the lower surface of the 
 terminal part of their bodies roughened like a rasp, and 
 with this they coil round and permanently hold the 
 females.* 
 
 When the two sexes follow exactly the same habits of 
 life, and the male has the censory or locomotive organs 
 more highly developed than those of the female, it may be 
 that the perfection of these is indispensable to the male for 
 finding the female; but in the vast majority of cases, they 
 serve only to give one male an advantage over another, for 
 with sufficient time the less well-endowed males would suc- 
 ceed in pairing with the females; and judging from the 
 structure of the female, they would be in all other respects 
 equally well adapted for their ordinary habits of life. Since 
 in such cases the males have acquired their present struct- 
 ure not from being better fitted to survive in the struggle 
 
 *M. Perrier advances this case ("Revue Scientifique," Feb. 1, 
 1873, p. 865) as one fatal to the belief in sexual selection, inasmuch 
 as he supposes that I attribute all the differences between the sexes 
 to sexual selection. This distinguished naturalist, therefore, like so 
 many other Frenchmen, has not taken the trouble to understand even 
 the first principles of sexual selection. An English naturalist insists 
 that the claspers of certain male animals could not have been devel- 
 oped threugh the choice of the female ! Had I not met with this 
 remark I should not have thought it possible for any one to have 
 read this chapter and to have imagined that I maintain that the 
 choice of the female had anything to do with the development of the 
 prehensile organs in the male.
 
 238 THE DESCENT OF MAN. 
 
 for existence, but from having gained an advantage ovei 
 other males, and from having transmitted this advantage to 
 their male offspring alone, sexual selection must here have 
 come into action. It was the importance of this distinction 
 which led me to designate this form of selection as sexual 
 selection. So again, if the chief service rendered to the 
 male by his prehensile organs is to prevent the escape of the 
 female before the arrival of other males, or when assaulted 
 by them these organs will have been perfected through 
 sexual selection, that is, by the advantage acquired by certain 
 individuals over their rivals. But in most cases of this 
 kind it is impossible to distinguish between the effects of 
 natural and sexual selection. Whole chapters could be 
 filled with details on the differences between the sexes 
 in their sensory, locomotive and prehensile organs. As, 
 however, these structures are not more interesting than 
 others adapted for the ordinary purposes of life I shall pass 
 them over almost entirely, giving only a few instances under 
 each class. 
 
 There are many other structures and instincts which 
 must have been developed through sexual selection, such 
 as the weapons of offense and the means of defense of the 
 males for fighting with and driving away their rivals their 
 courage and pugnacity their various ornaments their 
 contrivances for producing vocal or instrumental music 
 and their glands for emitting odors, most of these latter 
 structures serving only to allure or excite the female. It 
 is clear that these characters are the result of sexual and 
 not of ordinary selection, since unarmed, unornamented, or 
 unattractive males would succeed equally well in the battle 
 for life and in leaving a numerous progeny, but for the 
 presence of better endowed males. We may infer that this 
 would be the case, because the females, which are unarmed 
 and unornamented, are able to survive and procreate their 
 kind. Secondary "sexual characters of the kind just 
 referred to, will be fully discussed in the following chap- 
 ters, as being in many respects interesting, but especially 
 as depending on the will, choice, and rivalry of the indi- 
 viduals of either sex. When we bebold two males fighting 
 for the possession of the female, or several male birds dis- 
 playing their gorgeous plumage and performing strange 
 antics before an assembled body of females, we cannot doubt 
 that, though led by instinct, they know what they are
 
 SEXUAL SELECTION. 239 
 
 about, and consciously exert their mental and bodily 
 powers. 
 
 Just as man can improve the breed of his game-cocks by 
 the selection of those birds which are victorious in the 
 cock-pit, so it appears that the strongest and most vigorous 
 males, or those provided with the best weapons, have pre- 
 vailed under nature, and have led to the improvement of 
 the natural breed or species. A slight degree of variability 
 leading to some advantage, however slight, in reiterated 
 deadly contests would suffice for the work of sexual selec- 
 tion; and it is certain that secondary sexual characters are 
 eminently variable. Just as man can give beauty, accord- 
 ing to his standard of tase, to his male poultry, or more 
 strictly can modify the beauty originally acquired by the 
 parent species, can give to the Sebright bantam a new and 
 elegant plumage, an erect and peculiar carriage so it 
 appears that female birds in a state of nature have by a 
 long selection of the more attractive males added to 
 their beauty or other attractive qualities. No doubt 
 this implies powers of discrimination and taste on the part 
 of the female, which will at first appear extremely improb- 
 able; but by the facts to be adduced hereafter, I hope to 
 be able to show that the females actually have these 
 powers. When, however, it is said that the lower animals 
 have a sense of beauty, it must not be supposed that such 
 sense is comparable with that of a cultivated man, with his 
 multiform and complex associated ideas. A more just 
 comparison would be between the taste for the beautiful in 
 animals, and that in the lowest savages, who admire and 
 deck themselves with any brilliant, glittering, or curious 
 object. 
 
 From our ignorance on several points, the precise manner 
 in which sexual selection acts is somewhat uncertain. 
 Nevertheless, if those naturalists who already believe in the 
 mutability of species, will read the following chapters, they 
 will, I think, agree with me that sectual selection has 
 played an important part in the history of the organic 
 world. It is certain that among almost all animals there is 
 a struggle between the males for the possession of the 
 female. ' This fact is so notorious that it would be super- 
 fluous to give instances. Hence the females have the oppor- 
 tunity of selecting one out of several males, on the suppo- 
 sition that their mental capacity suffices for the exertion of
 
 240 THE DESCENT OF MAN. 
 
 a choice. In many cases special circumstances tend to 
 make the struggle between the males particularly severe. 
 Thus the males of our migratory birds generally arrive at 
 their places of breeding before the females, so that many 
 males are ready to contend for each female. I am informed 
 by Mr. Jenner Weir,, that the bird-catchers assert that this 
 is invariably the case with the nightingale and blackcap, 
 and with respect to the latter he can himself confirm the 
 statement. 
 
 Mr. Swaysland, of Brighton, has been in the habit during 
 the last forty years of catching our migratory birds on 
 their first arrival, and he has never known the females of 
 any species to arrive before their males. During one 
 spring he shot thirty-nine males of Ray's wagtail (Budytes 
 Itaii) before he saw a single female. Mr. Gould has ascer- 
 tained by the dissection of those snipes which arrive the 
 first in this country that the males come before the females. 
 And the like holds good with most of the migratory birds 
 of the United States.* The majority of the male salmon 
 in our rivers on coming up from the sea are ready to breed 
 before the females. So it appears to be with frogs and 
 toads. Throughout the great class of insects the males 
 almost always are the first to emerge from the pupal state, 
 so that they generally abound for a time before any females 
 can be seen, f The cause of this difference between the 
 males and females in their periods of arrival and maturity 
 is sufficiently obvious. Those males which annually f? :st 
 migrated into any country, or which in the spring were 
 first ready to breed, or the most eager, would leave the 
 largest number of offspring; and these would tend to in- 
 herit similar instincts and constitutions. It must be borne 
 in mind that it would have been impossible to change very 
 materially the time of sexual maturity in the females with- 
 out at the same time interfering with the period of the 
 
 *J. A. Allen on the "Mammals and \Vinter Birds of Florida,' 1 
 Bull. Comp. Zoology, Harvard College, p. 268. 
 
 f Even with those plants in which the sexes are separate, the male 
 flowers are generally mature before the female. As first shown by 
 <"". K. Sprengel, many hermaphrodite plants are dichogamons; that 
 is, their male and female organs are not ready at the same time, so 
 that they cannot be self-fertilized. Now in such Mowers the pollen 
 is in general matured before the stigma, though there are exceptional 
 cases in which the female organs are beforehand.
 
 SEXUAL SELECTION. 241 
 
 production of the young a period which must be deter- 
 mined by the seasons of the year. On the whole, there 
 can be no doubt that with almost all animals in which the 
 sexes are separate there is a constantly recurrent struggle 
 between the males for the possession of the females. 
 
 Our difficulty in regard to sexual selection lies in under- 
 standing how it is that the males which conquer other 
 males, or those which prove the most attrative to the 
 females, leave a greater number of offspring to inherit their 
 superiority than their beaten and less attractive rivals. 
 Unless this result does follow the characters which give to 
 certain males an advantage over others could not be per- 
 fected and augmented through sexual selection. When 
 the sexes exist in exactly equal numbers the worst endowed 
 males will (except where polygamy prevails) ultimately 
 find females and leave as many offspring as well fitted for 
 their general habits of life as the best-endowed males. 
 From various facts and considerations I formerly inferred 
 that with most animals, in which secondary sexual charac- 
 ters are well developed, the males considerably exceeded 
 the females in number; but this is not by any means 
 always true. If the males were to the females as two to 
 one, or three to two, or even in a somewhat lower ratio the 
 whole affair would be simple; for the better armed or more 
 attractive males would leave the largest number of offspring. 
 But after investigating as far as possible the numerical 
 proportion of the sexes I do not believe that any great in- 
 equality in number commonly exists. In most cases sexual 
 selection appears to have been effective in the following 
 manner: 
 
 Let us take any species, a bird for instance, and divide 
 the females inhabiting a district into two equal bodies, the 
 one consisting of the more vigorous and better-nourished 
 individuals, and the other of the less vigorous and healthy. 
 The former, there can be little doubt, would be ready to 
 breed in the spring before the others ; and this is the 
 opinion of Mr. Jenner Weir, who has carefully attended to 
 the habits of birds during many years. There can also be 
 no doubt that the most vigorous, best-nourished and earliest 
 breeders would on an average succeed in rearing the 
 largest number of fine offspring.* The males, as we have 
 
 * Here is excellent evidence on the character of the offspring from 
 an experienced ornithologist. Mr. J. A. Allen, in speaking (" Main-
 
 342 THE DESCENT OF MAN. 
 
 seen, are generally ready to breed before the females; the 
 strongest, and with some species the best armed of the 
 males, drive away the weaker; and the former would then 
 unite with the more vigorous and better-nourished females, 
 because they are the first to breed.* Such vigorous pairs 
 would surely rear a larger number of offspring than the 
 retarded females, which would be compelled to unite with 
 the conquered and less powerful males, supposing the sexes 
 to be numerically equal; and this is all that is wanted to 
 add, in the course of successive generations, to the size, 
 strength and courage of the males, or to improve their 
 weapons. 
 
 But in very many cases the males which conquer their 
 rivals do not obtain possession of the females, independently 
 of the choice of the latter. The courtship of animals is 
 by no means so simple and short an affair as might be 
 thought. The females are most excited by, or prefer pair- 
 ing with, the more ornamented males, or those which are 
 the best songsters, or play the best antics; but it is obviously 
 probable that they would at the same time prefer the more 
 vigorous and lively males, and this has in some cases been 
 confirmed by the actual observation.! Thus the more 
 vigorous females, which are the first to breed, will have the 
 choice of many males; and though they may not always 
 select the strongest or best armed, they will select those 
 which are vigorous and well armed, and in other respects 
 the most attractive. Both sexes, therefore, of such early 
 pairs would, as above explained, have an advantage over 
 others in rearing offspring ; and this apparently has 
 sufficed during a long course of generations to add not 
 
 mals and Winter Birds of E. Florida," p. 229) of the later broods 
 after the accidental destruction of the first, says that these " are found 
 to be smaller and paler- colored than those hatched earlier in the sea- 
 son. In cases where several broods are reared each year, as a general 
 rule the birds of the earlier broods seem in all respects the most per- 
 fect and vigorous." 
 
 * Hermann Muller has come to this same conclusion with respect 
 to those female bees which are the first to emerge from the pupa each 
 year. See his remarkable essay, " Anwendung den Darwin'schen 
 Lehre auf Bienen," " Verh. d. V. Jahrg.," xxix, p. 45. 
 
 f With respect to poultry, I have received information, hereafter to 
 be given, to this effect. Even with birds, such as pigeons, which 
 pair for life, the female, as I hear from Mr. Jenner Weir, will desert 
 her mate if he is injured or grows jiveak.
 
 SEXUAL SELEGTIOir. &3 
 
 only to the strength and fighting powers of the males, 
 but likewise to their various ornaments or other attractions. 
 In the converse and much rarer case of the males select- 
 ing particular females it is plain that those which were the 
 most vigorous and had conquered others would have the 
 freest choice; and it is almost certain that they would select 
 vigorous as well as attractive females. Such pairs would 
 have an advantage in rearing offspring, more especially if 
 the male had the power to defend the female during the 
 pairing-season as occurs with some of the higher animals, or 
 aided her in providing for the young. The same principles 
 would apply if each sex preferred and selected certain 
 individuals of the opposite sex; supposing that they selected 
 not only the more attractive, but likewise the more vigor- 
 ous individuals. 
 
 Numerical Proportion of the Two Sexes. I have remarked 
 that sexual selection would be a simple affair if the males 
 were considerably more numerous than the females. Hence 
 I was led to investigate, as far as I could, the proportions 
 between the two sexes of as many animals as possible; but 
 the materials are scanty. I will here give only a brief 
 abstract of the results, retaining the details for a supple- 
 mentary discussion so as not to interfere with the course of 
 my argument. Domesticated animals alone afford the 
 means of ascertaining the proportional numbers at birth; 
 but no records have been specially kept for this purpose. 
 By indirect means, however, I have collected a considerable 
 body of statistics, from which it appears that with most 
 of our domestic animals the sexes are nearly equal at birth. 
 Thus 25, 560 births of race-horses have been recorded during 
 twenty-one years, and the male births were to the female 
 births as 99.7 to 100. In greyhounds the inequality is 
 greater than with any other animal, for out of 6,878 births 
 during twelve years, the male births were to the female as 
 110.1 to 100. It is, however, in some degree doubtful 
 whether it is safe to infer that the proportion would be the 
 same under natural conditions as under domestication; for 
 slight and unknown differences in the conditions affect the 
 proportion of the sexes. Thus with mankind, the male 
 births in England are as 104.5, in Eussia as 108.9, and with 
 the Jews of Livonia as 120 to 100 female births. But I 
 shall recur to this curious point of the excess of male births
 
 244 THE DESCENT OF MAN. 
 
 in the supplement to this chapter. At the Cape of Good 
 Hope, however, male children of Europeon extraction have 
 been born during several years in the proportion of between 
 90 and 99 to 100 female children. 
 
 For our present purpose we are concerned with the pro- 
 portion of the sexes, not only at birth, but also at maturity, 
 and this adds another element of doubt; for it is a well- 
 ascertained fact that with man the number of males dying 
 before or during birth and during the first few years of 
 infancy is considerably larger than that of females. So it 
 almost certainly is with male lambs, and probably with 
 some other animals. The males of some species kill one 
 another by fighting; or they drive one another about until 
 they become greatly emaciated. They must also be often 
 exposed to various dangers while wandering about in eager 
 search for the females. In many kinds of fish the males 
 are much smaller than the females, and they are believed 
 often to be devoured by the latter or by other fishes. The 
 females of some birds appear to die earlier than the males; 
 they are also liable to be destroyed on their nests or while 
 in charge of their young. With insects the female larvae 
 are often larger than those of the males, and woiild conse- 
 quently be more likely to be devoured. In some cases the 
 mature females are less active and less rapid in their move- 
 ments than the males and could not escape so well from 
 danger. Hence, with animals in a state of nature we must 
 rely on mere estimation in order to judge of the propor- 
 tions of the sexes at maturity; and this is but little trust- 
 worthy except when the inequality is strongly marked. 
 Nevertheless, as far as a judgment can be formed, we may 
 conclude from the facts given in the supplement that the 
 males of some few mammals, of many birds, of some fish 
 and insects, are considerably more numerous than the 
 females. 
 
 The proportion between the sexes fluctuates slightly 
 during successive years; thus with race-horses, for every 
 100 mares born the stallions varied from 107.1 in one year 
 to 92.6 in another year, and with greyhounds from 116.3 
 to 95.3. But had larger numbers been tabulated through- 
 out an area more extensive than England these fluctuations 
 would probably have disappeared; and such as they are, 
 would hardly suffice to lead to effective sexual selection in 
 a state of nature. Nevertheless, in the cases of some few
 
 SEXUAL SELECTION. 245 
 
 wild animals, as shown in the supplement, the proportions 
 seem to fluctuate either during different seasons or in dif- 
 ferent localities in a sufficient degree to lead to such selec- 
 tion. For it should be observed that any advantage gained 
 during certain years or in certain localities by those males 
 which were able to conquer their rivals, or were the most 
 attractive to the females, would probably be transmitted to 
 the offspring and would not subsequently be eliminated. 
 During the succeeding seasons, when from the equality of 
 the sexes every male was able to procure a female, the 
 stronger or more attractive males previously produced would 
 still have at least as good a chance of leaving offspring as 
 the weaker or less attractive. 
 
 Polygamy. The practice of polygamy leads to the same 
 results as would follow from an actual inequality in the 
 number of the sexes; for if each male secures two or more 
 females many males cannot pair; and the latter assuredly 
 will be the weaker or less attractive individuals. Many 
 mammals and some few birds are polygamous, but with 
 animals belonging to the lower classes I have found no evi- 
 dence of this habit. The intellectual powers of such ani- 
 mals are, perhaps, not sufficient to lead them to collect and 
 guard a harem of females. That some relation exists be- 
 tween polygamy and the development of secondary sexual 
 characters appears nearly certain ; and this supports the 
 view that a numerical preponderance of males would be 
 eminently favorable to the action of sexual selection. 
 Nevertheless many animals which are strictly monogamous, 
 especially birds, display strongly marked secondary sexual 
 characters; while some few animals which are polygamous 
 do not have such characters. 
 
 We will first briefly run through the mammals and 
 then turn to birds. The gorilla seems to be polygamous, 
 and the male differs considerably from the female; so 
 it is with some baboons/ Which live in herds containing 
 twice as many adult females as males. In South America 
 the Mycetes caraya presents well-marked sexual differences, 
 in. color, -beard, and vocal organs ; and the male generally 
 lives with two or three wives; the male of the Cebus capuci- 
 nu$ differs somewhat from the female, and appears to be
 
 246 THE DESCENT OF MAN. 
 
 polygamous.* Little is known on this head with respect to 
 most other monkeys, but some species are strictly monoga- 
 mous. The ruminants are eminently polygamous,, and they 
 present sexual differences more frequently than almost any 
 other group of mammals; this holds good, especially in 
 their weapons, but also in other characters. Most deer, 
 cattle, and sheep are polygamous; as are most antelopes, 
 though some are monogamous. Sir Andrew Smith, in 
 speaking of the antelopes of S. Africa, says that in 
 herds of about a dozen there was rarely more than one 
 mature male. The Asiatic Antilope saiga appears to be the 
 most inordinate polygamist in the world; for Pallas f states 
 that the male drives away all rivals and collects a herd of 
 about a hundred females and kids together; the female is 
 hornless and has softer hair, but does not otherwise differ 
 much from the male. The wild horse of the Falkland 
 Islands and of the Western States of North America is 
 polygamous, but, except in his greater size and the propor- 
 tions of his body, differs but little from the mare. The 
 wild boar presents well-marked sexual characters, in his 
 great tusks and some other points. In Europe and in India 
 he leads a solitary life, except during the breeding-season ; 
 but as is believed by Sir W. Elliot, who has had many 
 opportunities in India of observing this animal, he consorts 
 at this season with several females. Whether this holds 
 good in Europe is doubtful, but it is supported by some 
 evidence. The adult male Indian elephant, like the boar, 
 passes much of his time in solitude; but as Dr. Campbell 
 states, when with others, " it is rare to find more than one 
 male with a whole herd of females ;" the larger males 
 expelling or killing the smaller and weaker ones. The 
 male differs from the female in his immense tusks, greater 
 size, strength and endurance; so great is the difference in 
 these respects, that the males when caught are valued at 
 
 *On the Gorilla, Savage and Wyman, "Boston Journal of Nat. 
 Hist.," vol. v, 1845-47, p. 423. On Cynocephalus, Brebm, " lllust. 
 Thierleben," B.i, 1864, s. 77. On Mycetes, Rengger, " Naturgesch. : 
 Saugethiere von Paraguay," 1830, ss. 14, 20. Cebus, Brehm, ibid, s. 
 
 t Pallas, "Spicilegia Zoolog., Fasc.," xii, 1777, p. 29. Sir Andrew 
 Smith, " Illustrations of the Zoology of S. Africa," 1849, pi. 29, on 
 the Kobus. Owen, in his " Anatomy of Vertebrates " (vol. iii, 1868, 
 p. 633) gives a table showing incidentally which species of antelopes 
 are gregarious.
 
 SEXUAL SELECTION. 247 
 
 one-fifth more than the females.* The sexes of other 
 pachydermatous animals differ very little or not at all, and, 
 as far as known, they are not polygamists. Nor have I 
 heard of any species in the orders of Cheiroptera, Edentata, 
 Insectivora and Rodents being polygamous, excepting that 
 among the Eodents, the common rat, according to some 
 rat-catchers, lives with several females. Nevertheless the 
 two sexes of some sloths (Edentata) differ in the character 
 and color of certain patches of hair on their shoulders, f 
 And many kinds of bats (Cheiroptera) present well- 
 marked sexual differences, chiefly in the males possessing 
 odoriferous glands and pouches, and by their being of 
 a lighter color. J In the great order of Rodents, as far as I 
 can learn, the sexes rarely differ, and when they do so it 
 is but slightly in the tint of the fur. 
 
 As I hear from Sir Andrew Smith, the lion in S. Africa 
 sometimes lives with a single female, but generally with 
 more, and, in one case, was found with as many as five 
 females; so that he is polygamous. As far as I can dis- 
 cover he is the only polygamist among all the terrestrial 
 Carnivora, and he alone presents well-marked sexual char- 
 acters. If, however, we turn to the marine Carnivora, as 
 we shall hereafter see, the case is widely different; for many 
 species of seals offer extraordinary sexual differences, 
 and they are eminently polygamous. Thus, according to 
 Peron, the male sea -elephant of the Southern Ocean 
 always possesses several females, and the sea-lion of Forster 
 is said to be surrounded by from twenty to thirty females. 
 In the North the male sea-bear of Steller is accompanied 
 by even a greater number of females. It is an interesting 
 fact, as Dr. Gill remarks, that in the monogamous species, 
 " or those living in small communities, there is little differ- 
 ence in size between the males and females; in the social 
 species, or rather those of which the males have harems, 
 the males are vastly larger than the females. " 
 
 *Dr. Campbell, in " Proc. Zoolog. Soc.," 1869, p. 138. See also 
 an interesting paper, by Lieut. Joknstone, in ' ' Proc. Asiatic Soc. of 
 Bengal," May, 1868. 
 
 fDr. Gray, in "Annals and Mag. of Nat. Hist.," 1871, p. 302. 
 
 fSee Dr. Dobson's excellent paper in "Proc. Zoolog. Soc.," 1873, 
 p. 241. 
 
 The Eared Seals, " American Naturalist," vol. iv, Jan., 1871.
 
 248 THE DESCENT OF MAN. 
 
 Among birds, many species, the sexes of which differ 
 greatly from each other, are certainly monogamous. In 
 Great Britain we see well-marked sexual differences, for 
 instance, in the wild duck which pairs with a single female, 
 the common blackbird, and the bullfinch which is said to 
 pair for life. I am informed by Mr. Wallace that the like 
 is true of the Chatterers or Cotingidse of South America, 
 and of many other birds. In several groups I have not 
 been able to discover whether the species are polygamous or 
 monogamous. Lesson says that birds of paradise, sc 
 remarkable for their sexual differences, are potygamous, but 
 Mr. Wallace doubts whether he had sufficient evidence. 
 Mr. Salvin tells me he has been led to believe that hum- 
 ming - birds are polygamous. The male widow - bird, 
 remarkable for his caudal plumes, certainly seems to be a 
 polygamist.* I have been assured by Mr. Jenner Weir and 
 by others that it is somewhat common for three starlings to 
 frequent the same nest; but whether this is a case of 
 polygamy or polyandry has not been ascertained. 
 
 The Gallinaceae exhibit almost as strongly marked sexual 
 differences as birds of paradise or humming-birds, and 
 many of the species are, as is well known, polygamous; 
 others being strictly monogamous. What a contrast is pre- 
 sented between the sexes of the polygamous peacock or 
 pheasant, and the monogamous guinea-fowl or partridge! 
 Many similar cases could be given, as in the grouse tribe, 
 in which the males of the polygamous capercailzie and 
 black-cock differ greatly from the females; while the sexes 
 of the monagamous red grouse and ptarmigan differ very 
 little. In the Cursores, except among the bustards, few 
 species offer strongly-marked sexual differences, and the 
 great bustard ( Otis tarda) is said to be polygamous. With 
 the Grallatores extremely few species differ sexually, but 
 the ruff (Machetes pitgnax) affords a marked exception and 
 this species is believed by Montagu to be a polygamist. 
 Hence it appears that among birds there often exists a close 
 relation between polygamy and the development of strongly - 
 
 *"The Ibis," vol. iii, 1861, p. 133, on the Progne Widow-bird. 
 See also on tbe Vidua axillaris, ibid., vol. ii, 1860, p. 211. On the 
 polygamy of the Capercailzie and Great Bustard, see L. Lloyd, 
 "Game "Birds of Sweden," 1867, pp. 19, 182. Montagu and Selby 
 speak of the Black Grouse as polygamous and of the Bed Grouse aa 
 monogamous.
 
 SELUAL SELECTION. 249 
 
 marked sexual differences. I asked Mr. Bartlett, of the 
 Zoological Gardens, who has had very large experience 
 with birds, whether the male &ragopan (one of the Gailin- 
 acese) was polygamous, and I was struck by his answering, 
 " I do not know, but should think so from his splendid 
 colors." 
 
 It deserves notice that the instinct of pairing with a single 
 female is easily lost under domestication. The wild-duck 
 is strictly monogamous, the domestic duck highly polyga- 
 mous. The Rev. W. D. Fox informs me that out of some 
 half -tamed wild ducks, on a large pond in his neighbor- 
 hood, so many mallards were shot by the gamekeeper that 
 only one was left for every seven or eight females; yet 
 unusually large broods were reared. The guinea-fowl is 
 strictly monogamous; but Mr. Fox finds that his birds suc- 
 ceed best when he keeps one cock to two or three hens. 
 Canary-birds pair in a state of nature, but the breeders in 
 England successfully put one male to four or five females. 
 I have noticed these cases as rendering it probable that 
 wild monogamous species might readily become either tem- 
 porarily or permanently polygamous. 
 
 Too little is known of the habits of reptiles and fishes 
 to enable us to speak of their marriage arrangements. The 
 stickle-back (Gasterosteus), however, is said to be a polyg- 
 aniist;* and the male during the breeding season differs 
 conspicuously from the female. 
 
 To sum up on the means through which, as far as we can 
 judge, sexual selection has led to the development of second- 
 ary sexual characters. It has been shown that the largest 
 number of vigorous offspring will be reared from the pair- 
 ing of the strongest and best-armed males, victorious in 
 contests over other males, with the most vigorous and best- 
 nourished females, which are the first to breed in the spring. 
 If such females select the more attractive, and at the same 
 time vigorous males, they will rear a larger number of off- 
 spring than the retarded females, which must pair with the 
 less vigorous and less attractive males. So it will be if the 
 more vigorous males select the more attractive and at the 
 same timg healthy and vigorous females; and this will espe- 
 cially hold good if the male defends the female and aids 
 in providing food for the young. The advantage thus 
 
 *Noel Humphreys, " River Gardens," 1857.
 
 250 THE DESCENT OF MAN. 
 
 gained by the more vigorous pairs in rearing a larger 
 number of offspring has apparently sufficed to render sex- 
 ual selection efficient. But a large numerical preponder- 
 ance of males over females will be still more efficient; 
 whether the preponderance is only occasional and local, or 
 permanent; whether it occurs at birth, or afterward from 
 the greater destruction of the females; or whether it in- 
 directly follows from the practice of polygamy. 
 
 The Male Generally More Modified than the Female. 
 Throughout the animal kingdom when the sexes differ 
 in external appearance, it is, with rare exceptions, the male 
 which has been the more modified; for, generally, the 
 female retains a closer resemblance to the young of her own 
 species and to other adult members of the same group. 
 The cause of this seems to lie in the males of almost all 
 animals having stronger passions than the females. Hence 
 it is the males that fight together and sedulously display 
 their charms before the females; and the victors transmit 
 their superiority to their male offspring. Why both sexes 
 | do not thus acquire the characters of their fathers will be 
 I considered hereafter. That the males of all mammals 
 eagerly pursue the females is notorious to every one. So it 
 is with birds; but many cock birds do not so much pursue 
 the hen, as display their plumage, perform strange antics, 
 and pour forth their song in her presence. The male in the 
 few fish observed seerns much more eager than the female; 
 and the same is true of alligators, and apparently of 
 Batrachians. Throughout the enormous class of insects, 
 as Kirby remarks,* " the law is that the male shall seek the 
 female," Two good authorities, Mr. Blackwall and Mr. C. 
 Spencc Bate, tell me that the males of spiders and crusta- 
 ceans are more active and more erratic in their habits than 
 the females. When the organs of sense or locomotion are 
 present in the one sex of insects and cru<t:iff:ins and absent 
 in the other, or when, as is frequently the case, they are 
 more highly developed in the one than in the other, it is, as 
 far as I can discover, almost invariably the male which 
 retains such organs, or has them most developed; and this 
 
 * Kirby and Spence, ;: Introduction to Entomology," vol. iii, 1826, 
 p. 342.
 
 SEXUAL SELECTION. 251 
 
 shows that the male is the more active member in the 
 courtship of the sexes.* 
 
 The female, on the other hand, with the rarest excep- 
 tions, is less eager than the male. As the illustrious 
 Hunter f long ago observed she generally " requires to be 
 courted;" she is coy, and may often be seen endeavoring for | 
 a long time to escape from the male. Every observer of 
 the habits of animals will be able to call to mind instances 
 of this kind. It is shown by various facts, given hereafter, 
 and by the results fairly attributable to sexual selection, 
 that the female, though comparatively passive, generally 
 exerts some choice and accepts one male in preference to 
 others. Or she may accept, as appearances would some- 
 times lead us to believe, not the male which is the most 
 attractive to her, but the one which is the least dis- 
 tasteful. The exertion of some choice on the part of the 
 female seems a law almost as general as the eagerness of the 
 male. 
 
 We are naturally led to inquire why the male, in so 
 many and such distinct classes, has become more eager 
 than the female, so that he searches for her and plays 
 the more active part in courtship. It would be no 
 advantage and some loss of power if each sex searched 
 for the other; but why should the male almost always be 
 the seeker? The ovules of plants after fertilization have 
 to be nourished for a time; hence the pollen is necessarily 
 brought to the female organs being placed on the stigma, 
 by means of insects or the wind, or by the spontaneous 
 movements of the stamens; and in the Algae, etc., by the 
 locomotive power of the antherozooids. With lowly-organ- 
 ized aquatic animals, permanently affixed to the same spot 
 and having their sexes separate, the male element is invari- 
 ably brought to the female; and of this we can see the 
 
 * One parasitic Hymenopterous insect (Westwood, " Modern Class, 
 of Insects," vol. ii, p. 160) forms an exception to the rule, as the 
 male has rudimentary wings, and never quits the cell in which it is 
 born, while the female has well-developed wings. Audouin believes 
 that the females of this species are impregnated by the males which 
 are born in the same cells with them; but it is much more probable 
 that the females visit other cells, so that close interbreeding is thus 
 avoided. 'We shall hereafter meet in various classes, with a few 
 exceptional cases, in which the female, instead of the male, is the 
 Keeker and wooer. 
 
 t" Essays and Observations," edited by Owen, vol. i, 1861, p. 194.
 
 252 THE DESCENT OF MAN. 
 
 reason, for even if the ova were detached before fertiliza- 
 tion, and did not require subsequent nourishment or pro- 
 tection, there would yet be greater difficulty iu transporting 
 them than the male element, because, being larger than 
 the latter, they are produced in far smaller numbers. So 
 that many of the lower animals are, in this respect, analo- 
 gous with plants.* The males of affixed and aquatic ani- 
 mals having been led to emit their fertilizing elements in 
 this way, it is natural that any of their descendants, which 
 rose in the scale and became locomotive, should retain the 
 same habit; and they would approach the female as closely 
 as possible, in order not to risk the loss of the fertilizing 
 element in a long passage of it through the water. With 
 some few of the lower animals, the females alone are fixed, 
 and the males of these must be the seekers. But it is dif- 
 ficult -to understand why the males of species, of which the 
 progenitors were primordially free, should invariably have 
 acquired the habit of approaching the females, instead of 
 being approached by them. But in all cases, in order that 
 the males should seek efficiently, it would be necessary that 
 they should be endowed with strong passions; and the 
 acquirement of such passions would naturally follow from 
 the more eager leaving a larger number of offspring than 
 the less eager. 
 
 The great eagerness of the males has thus indirectly led 
 to their much more frequently developing secondary sexual 
 characters than the females. But the development of such 
 characters would be much aided if the males were more 
 liable to vary than the females as I concluded they were 
 after a long study of domesticated animals. Von Nathu- 
 sius, who has had very wide experience, is strongly of the 
 same opinion, f Good evidence also in favor of this con- 
 clusion can be produced by a comparison of the two sexes 
 in mankind. During the Novara Expedition^ a vast 
 
 *Prof. Sachs (" Lehrbuch der Botanik," 1870, s. 633), in speaking 
 of the male and female reproductive cells, remarks, ' verhalt sich 
 die eine bei der Vereinigung activ, . . . die andere erscheint bei 
 der Vereinigung pa.-siv." 
 
 f ' Vortrage iiber Viehzucht," 1872, p. 63. 
 
 $ : ' Reise der Xovara, Authropolog. Theil," 1867, ss. 216-269. The 
 results were calculated by Dr. Weisbach from measurements made 
 by Drs. K. Scherzer and Schwarz. On the greater variability of the 
 males of domesticated animals, see my " Variation of Animals and 
 Plants uoder Domestication/' vol. u, 1868, p. 75.
 
 I 
 
 SEXUAL SELECTION'. 253 
 
 number of measurements was made of various parts of the 
 body in different races, and the men were found in almost 
 every case to present a greater range of variation than 
 the women ; but I shall have to recur to this subject in 
 a future chapter. Mr. J. Wood,* who has carefully 
 attended to the variation of the muscles in man, puts in 
 italics the conclusion that " the greatest number of 
 abnormalities in each subject is found in the males." He 
 had previously remarked that " altogether in 102 subjects, 
 the varieties of redundancy were found to be half as many 
 again as in females, contrasting widely with the greater 
 frequency of deficiency in females before described." Prof. 
 Macalister likewise remarks! that variations in the muscles 
 "are probably more common in males than females." 
 Certain muscles which are not normally present in man- 
 kind are also more frequently developed in the male than 
 in the female sex, although exceptions to this rule are said 
 to occur. Dr. Burt Wilder}; has tabulated the cases of 152 
 individuals with supernumerary digits, of which 86 were 
 males and 39, or less than half, females, the remaining 27 
 being of unknown sex. It should not, however, be over- 
 looked that women would more frequently endeavor to con- 
 ceal a deformity of this kind than men. Again, Dr. L. 
 Meyer asserts that the ears of man are more variable in 
 form than those of a woman. Lastly, the temperature is 
 more variable in man than in woman. R 
 
 The cause of the greater general variability in the male 
 sex than in the female is unknown, except in so far as sec- 
 ondary sexual characters are extraordinarily variable and 
 are usually confined to the males; and, as we shall presently 
 see, this fact is, to a certain extent, intelligible. Through 
 the action of sexual and natural selection male animals 
 have been rendered in very many instances widely different 
 from their females ; but independently of selection the 
 two sexes, from differing constitutionally, tend to vary in 
 
 * " Proceedings Royal Soc.," vol. xvi, July, 1868, pp. 519, 534. 
 
 f " Proc. Royal Irish Academy," vol. x, 1868, p. 123. 
 
 J " Massachusetts Medical Soc.," vol. ii, No. 3, 1868, p. 9. 
 
 " Arqhiv fur Path. Anat. und Phys. ," 1871, p. 488. 
 
 I The conclusions recently arrived at by Dr. J. Stockton Hough, on. 
 the temperature of man, are given in the " Pop. Science Review," 
 Jan. 1, 1874, p. 97.
 
 254 THE DESCENT OF MAN. 
 
 a somewhat different manner. The female has to expend 
 much organic matter in the formation of her ova, whereas 
 the male expends much force in fierce contests with his 
 rivals, in wandering about in search of the female, in exert- 
 ing his voice, pouring out odoriferous secretions, etc. ; and 
 this expenditure is generally concentrated within a short 
 period. The great vigor of the male during the season of 
 love seems often to intensify his colors independently of 
 any marked difference from the female.* In mankind, 
 and even as low down in the organic scale as in the Lepi- 
 doptera, the temperature of the body is higher in the male 
 than in the female, accompanied in the case of man by a 
 slower pulse, f On the whole, the expenditure of matter 
 and force by the two sexes is probably nearly equal, though 
 effected in very different ways and at different rates. 
 
 From the causes just specified the two sexes can hardly 
 fail to differ somewhat in constitution, at least during the 
 breeding season; and although they may be subjected to 
 exactly the same conditions they will tend to vary in a 
 different manner. If such variations are of no service to 
 either sex they will not be accumulated and increased by 
 sexual or natural selection. Nevertheless, they may be- 
 come permanent if the exciting cause acts permanently; 
 and in accordance with a frequent form of inheritance 
 they may be transmitted to that sex alone in which they 
 first appeared. In this case the two sexes will come to 
 present permanent, yet unimportant, differences of char- 
 acter. For instance, Mr. Allen shows that with a large 
 number of birds inhabiting the northern and southern 
 United States, the specimens from the south are darker- 
 colored than those from the north; and this seems to be 
 the direct result of the difference in temperature, light, etc., 
 between the two regions. Now, in some few cases, the 
 
 *Prof. Mantegazza is inclined to believe (" Lettera a Carlo Dar- 
 win," " Archivio per 1'Anthropologia," 1871, p. 306) that the bright 
 colors, common in so many male animals, are due to the presence and 
 retention by them of the spermatic fluid; but this can hardly be the 
 case; for many male birds, for instance young pheasants, become 
 brightly colored in the autumn of their first year. 
 
 f For mankind, see Dr. J. Stockton Hough, whose conclusions are 
 given in the " Pop. Science Review," 1874, p. 97. See Girard's 
 observations on the Lepidoptera, as given in the "Zoological Record," 
 1869, p. 347.
 
 8EXVAL SELECTION". 255 
 
 two sexes of the same species appear to have been differ- 
 ently affected; in the Agelceus phc&niceus the males have 
 had 'their colors greatly intensified in the south; whereas 
 with Cardinalis virginianus it is the females which have 
 been thus affected; with Quiscalus major the females have 
 been rendered extremely variable in tint, while the males 
 remain nearly uniform.* 
 
 A few exceptional cases occur in various classes of ani- 
 mals, in which the females instead of the males have 
 acquired well-pronounced secondary sexual characters, such 
 as brighter colors, greater size, strength or pugnacity. 
 With birds there has sometimes been a complete transposi- 
 tion of the ordinary characters proper to each sex; the 
 females having become the more eager in courtship, the 
 males remaining comparatively passive, but apparently 
 selecting the more attractive females, as we may infer from 
 the results. Certain hen birds have thus been rendered 
 more highly colored or otherwise ornamented, as well as 
 more powerful and pugnacious than the cocks ; these 
 characters being transmitted to the female offspring alone. 
 
 It may be suggested that in some cases a double process 
 of selection has been carried on; that the males have selected 
 the more attractive females and the latter the more attract- 
 ive males. This, process, however, though it might lead 
 to the modification of both sexes, would not make the one 
 sex different from the other, unless indeed their tastes for 
 the beautiful differed; but this is a supposition too improba- 
 ble to be worth considering in the case of any animal, except- 
 ing man. There are, however, many animals in which the 
 sexes resemble each other, both being furnished with the 
 same ornaments, which analogy would lead us to attribute 
 to the agency of sexual selection. In such cases it may be 
 suggested with more plausibility that there has been a 
 double or mutual process of sexual selection; the more 
 vigorous and precocious females selecting the more 
 attractive and vigorous males, the latter rejecting all 
 except the more attractive females. But from what we 
 know of the habits of animals, this view is hardly probable, 
 for the male is generally eager to pair with any female. It 
 is more probable that the ornaments common to both sexes 
 were acquired by one sex, generally the male, and then 
 
 * " Mammals and Birds of E. Florida," pp. 234, 280, 295.
 
 S56 THE DESCENT OF MAX. 
 
 transmitted to the offspring of both sexes. If, indeed, 
 during a lengthened period the males of any species were 
 greatly to exceed the females in number, and then during 
 another lengthened period, but under different conditions, 
 the reverse were to occur, a double, but not simultaneous, 
 process of sexual selection might easily be carried on, by 
 which the two sexes might be rendered widely different. 
 
 We shall hereafter see that many animals exist, of which 
 neither sex is brilliantly colored or provided with special 
 ornaments, and yet the members of both sexes or of one 
 alone have probably acquired simple colors, such as white 
 or black, through sexual selection. The absence of bright 
 tints or other ornaments may be the result of variations of 
 the right kind never having occurred, or of the animals 
 themselves having preferred plain black or white. Obscure 
 tints have often been developed through natural selection for 
 the sake of protection, and the acquirement through sexual 
 selection of conspicuous colors appears to have been some- 
 times checked from the danger thus incurred. But in 
 other cases the males during long ages may have struggled 
 together for the possession of the females, and yet no effect 
 will have been produced, unless a larger number of 
 offspring were left by the more successful males to inherit 
 their superiority than by the less successful; and this, as 
 previously shown, depends on many complex contingencies. 
 
 Sexual selection acts in a less rigorous manner than 
 natural selection. The latter produces its effects by the 
 life or death at all ages of the more or less successful indi- 
 viduals. Death, indeed, not rarely ensues from the 
 conflicts of rival males. But generally the less successful 
 male merely fails to obtain a female, or obtains a retarded 
 and less vigorous female later in the season, or, if polyga- 
 mous, obtains fewer females; so that they leave fewer, less 
 vigorous, or no offspring. In regard to structures acquired 
 through ordinary or natural selection there is in most cases, 
 as long as the conditions of life remain the same, a limit to 
 the amount of advantageous modification in relation to 
 certain special purposes; but in regard to structures adapted 
 to make one male victorious over another, either in fighting 
 or in charming the female, there is no definite limit to the 
 amount of advantageous modification; so that as long as 
 the proper variations arise the work of sexual selection will 
 go on. This circumstance may partly account for the
 
 SEXUAL SELECTION. 257 
 
 frequent and extraordinary amount of variability presented 
 by secondary sexual characters. Nevertheless, natural 
 selection will determine that such characters shall not be 
 acquired by the victorious males, if they would be highly 
 injurious, either by expending too much of their vital 
 powers or by exposing them to any great danger. The 
 development, however, of certain structures of the horns, 
 for instance, in certain stags has been carried to a won- 
 derful extreme; and in some cases to an extreme which, as 
 far as the general conditions of life are concerned, must be 
 slightly injurious to the male. From this fact we learn 
 that the advantages which favored males derive from con- 
 quering other males in battle or courtship, and thus leaving 
 a numerous progeny, are in the long run greater than those 
 derived from rather more perfect adaptation to their condi- 
 tions of life. We shall further see, and it could never have 
 been anticipated, that the power to charm the female has 
 sometimes been more important than the power to conquer 
 other males in battle. 
 
 Laws of Inheritance. In order to understand how sexual 
 selection has acted on many animals of many classes, and 
 in the course of ages has produced a conspicuous result, it 
 is necessary to bear in mind the laws of inheritance as far 
 as they are known. Two distinct elements are included 
 under the term "inheritance" the transmission and the 
 development of characters ; but as these generally go 
 together the distinction is often overlooked. We see this 
 distinction in those characters which are transmitted 
 through the early years of life, but are developed only at 
 maturity or during old age. We see the same distinction 
 more clearly with secondary sexual characters, for these are 
 transmitted through both sexes, though developed in one 
 alone. That they are present in both sexes is manifest 
 when two species having strongly marked sexual characters 
 are crossed, for each transmits the characters proper to its 
 own male- and female sex to the hybrid offspring of either 
 sex. The same fact is likewise manifest when characters 
 proper to the male are occasionally developed in the female 
 when ghe grows old or becomes diseased, as, for instance, 
 when the common hen assumes the flowing tail-feathers, 
 hackles, comb, spurs, voice, and even pugnacity of the 
 cock. Conversely the same thing is evident more or less
 
 058 THE DESCENT OF MAN. 
 
 plainly with castrated males. Again, independently of 
 old age or disease, characters are occasionally transferred 
 from the male to the female, as when in certain breeds of 
 the fowl spurs regularly appear in the young and healthy 
 females. But in truth they are simply developed in the 
 female; for in every breed each detail in the structure of 
 the spur is transmitted through the female to her male off- 
 spring. Many cases will hereafter be given where the 
 female exhibits more or less perfectly characters proper to 
 the male, in whom they must have been first developed and 
 then transferred to the female. The converse case of the 
 first development of characters in the female and of trans- 
 ference to the male is less frequent; it Avill therefore be 
 well to give one striking instance. With bees the pollen- 
 collecting apparatus is used by the female alone for gather- 
 ing pollen for the larvae, yet in most of the species it is 
 partially developed in the males to whom it is quite useless, 
 and it is perfectly developed in the males of Bombus or the 
 humble-bee.* As not a single other Hymen opterous insect, 
 not even the wasp, which is closely allied to the bee, is 
 provided with a pollen-collecting apparatus, we have no 
 grounds for supposing that male bees primordially collected 
 pollen as well as the females; although we have some reason 
 to suspect that male mammals primordially suckled their 
 young as well as the females. Lastly, in all cases of rever- 
 sion characters are transmitted through two, three or many 
 more generations, and are then developed under certain 
 unknown favorable conditions. This important distinction 
 between transmission and development will be best kept in 
 mind by the aid of the hypothesis of pangenesis. Accord- 
 ing to this hypothesis every unit or cell of the body throws 
 off gemmules or undeveloped atoms, which are transmitted 
 to the offspring of both sexes, and are multiplied by self- 
 division. They may remain undeveloped during the early 
 years of life or during successive generations; and their 
 development into units or cells, like those from which they 
 were derived, depends on their affinity for and union with 
 other units or cells previously developed in the due order 
 of growth. 
 Inheritance at Corresponding Periods of Life. This 
 
 * H. Miiller, " Anwendung der Darwin'sclieu Lehre." etc, Verb, 
 d. n. V. Jahrg. xxix, p. 42.
 
 SEXUAL SELECTION. 259 
 
 tendency is well-established. A new character, appearing 
 in a young animal, whether it lasts throughout life or is 
 only transient, will, in general, reappear in the offspring at 
 the same age and last for the same time. If, on the other 
 hand, a new character appears at maturity, or even during 
 old age, it tends to reappear in the offspring at the same 
 advanced age. When deviations from this rule occur, the 
 transmitted characters much oftener appear before than 
 after the corresponding age. As I have dwelt on this sub- 
 ject sufficiently in another work,* I will here merely give 
 two or three instances, for the sake of recalling the subject 
 to the reader's mind. In several breeds of the fowl, the 
 down-covered chickens, the young birds in their first true 
 plumage, and the adults differ greatly from one another, as 
 well as from their common parent- form, the Gallus bankiva; 
 and these characters are faithfully transmitted by each 
 breed to their offspring at the corresponding periods of 
 life. For instance, the chickens of spangled Hamburgs, 
 while covered with down, have a few dark spots on the 
 head and rump, but are not striped longitudinally, as in 
 many other breeds; in their first true plumage, " they are 
 beautifully penciled/' that is, each feather is transversely 
 marked by numerous dark bars; but in their second plum- 
 age the feathers all become spangled or tipped with a dark 
 round spot.f Hence in this breed variations have occurred 
 at, and been transmitted to, three distinct periods of life. 
 The pigeon offers a more remarkable case, because the abo- 
 riginal parent-species does not undergo any change of plum- 
 age with advancing age, excepting at maturity the breast 
 becomes more iridescent ; yet there are breeds which do 
 not acquire their characteristic colors until they have 
 moulted two, three, or four times; and these modifications 
 of plumage are regularly transmitted. 
 
 Inheritance at Corresponding Seasons of the Year. With 
 
 *"The Variation of Animals and Plants under Domestication," 
 vol. ii, 1868, p. 75. In tlie last chapter but one the, provisional hypo- 
 thesis of pangenesis, above alluded to, is fully explained. 
 
 f These facts are given on the high authority of a great breeder, 
 Mr. Teebay; see Tegetmeier's " Poultry Book," 1868, p. 158. On 
 the characters of chickens of different breeds, and on the breeds of 
 the pigeon, alluded to in the following paragraph, see " Variation of 
 Animals," etc., vol. i, pp. 160, 249; vol. ii, p. 77.
 
 260 THE DESCENT OF MAN. 
 
 animals in a state of nature, innumerable instances occur 
 of characters appearing periodically at different seasons. 
 We see this in the horns of the stag, and in the fur of the 
 Arctic animals, which becomes thick and white during the 
 winter. Many birds acquire bright colors and other deco- 
 rations during the breeding-season alone. Pallas states,* 
 that in Siberia domestic cattle and horses become lighter- 
 colored during the winter; and I have myself observed, and 
 heard of similar strongly-marked changes of color, that is, 
 from brownish-cream color or reddish-brown to a perfect 
 white, in several ponies in England. Although I do not know 
 that this tendency to change the color of the coat during 
 different seasons is transmitted, yet it probably is so, as all 
 shades of color are strongly inherited by the horse. Nor is 
 this form of inheritance as limited by the seasons, more 
 remarkable than its limitation by age or sex. 
 
 Inheritance as Limited by Sex. The equal transmission 
 of characters to both sexes is the commonest form of inher- 
 itance, at least with those animals which do not present 
 strongly-marked sexual differences, and indeed with many 
 of these. But characters are somewhat commonly trans- 
 ferred exclusively to that sex in which they first appear. 
 Ample evidence on this head has been advanced in my work 
 on "Variation Under Domestication," but a few instances 
 may here be given. There are breeds of the sheep and goat, 
 in which the horns of the male differ greatly in shape from 
 those of the female; and these differences acquired under 
 domestication are regularly transmitted to the same sex. 
 As a rule, it is the females alone in cats which are tortoise- 
 shell, the corresponding color in the males being rusty-red. 
 With most breeds of the fowl the characters proper to each 
 sex are transmitted to the same sex alone. So general is 
 this form of transmission that it is an anomaly when varia- 
 tions in certain breeds are transmitted equally to both 
 sexes. There are also certain sub-breeds of the fowl in 
 which the males can hardly be distinguished from one 
 another, while/ the females differ considerably in color. 
 The sexes of the pigeon in the parent-species do not differ 
 
 * " Novae species Quadrupedum e Glirium ordine," 1778, p. 7. On 
 the transmission of color by the horse, see " Variation of Animals, 
 etc., under Domestication," vol. i, p. 51. Also vol. ii, p. 71, for a 
 general discussion on " Inheritance as Limited by Sex."
 
 SEXUAL SELECTION. 261 
 
 in any external character; nevertheless, in certain domesti- 
 cated breeds the male is colored differently from the female.* 
 The wattle in the English carrier pigeon and the crop in the 
 Pouter are more highly developed in the male than in the 
 female; and although these characters have been gained 
 through long-continued selection by man, the slight differ- 
 ences between the sexes are wholly due to the form of 
 inheritance which has prevailed; for they have arisen, not 
 from, but rather in opposition to, the wish of the breeder. 
 
 Most of our domestic races have been formed by the 
 accumulation of many slight variations; and as some of the 
 successive steps have been transmitted to one sex alone, and 
 some to both sexes, we find in the different breeds of the 
 same species all gradations between great sexual dissimilar- 
 ity and complete similarity. Instances have already been 
 given with the breeds of the fowl and pigeon, and under 
 nature analogous cases are common. With animals under 
 domestication, but whether in nature I will not venture to 
 say, one sex may lose characters proper to it, and may thus 
 come somewhat to resemble the opposite sex; for instance, 
 the males of some breeds of the fowl have lost their mascu- 
 line tail-plumes and hackles. On the other hand, the dif- 
 ferences between the sexes may be increased under domesti- 
 cation, as with merino sheep, in which the ewes have lost 
 their horns. Again, characters proper to one sex may sud- 
 denly appear in the other sex; as in those sub-breeds of the 
 fowl in which the hens acquire spurs while young; or, as in 
 certain Polish sub-breeds, in which the females, as there is 
 reason to believe, originally acquired a crest, and subse- 
 quently transferred it to the males. All these cases are 
 intelligible on the hypothesis of pangenesis; for they depend 
 on the gemmules of certain parts, although present in both 
 sexes, becoming, through the influence of domestication, 
 either dormant or developed in either sex. 
 
 There is one difficult question which it will be convenient 
 to defer to a future chapter ; namely, whether a character 
 at first developed in both sexes could through selection be 
 limited in its development to one sex alone. If, for 
 instance, a breeder observed that some of his pigeons (of 
 
 * Dr. Ghapuis, " Le Pigeon Voyageur Beige," 1865, p. 87. Boitard 
 et Corbie, "Les Pigeons de Voliere," etc., 1824, p. 173. See, also, 
 on similar differences in certain breeds at Modena, " Le variazioul del 
 Colombi domestiei," del Paolo Bonizzi, 1873.
 
 262 THE DESCENT OF MAN. 
 
 which the characters are usually transferred in an equal 
 degree to both sexes) varied into pale blue, could he by 
 long-continued selection make a breed, in which the males 
 alone should be of this tint, while the females remained 
 unchanged? I will here only say that this, though perhaps 
 not impossible, would be extremely difficult; for the natural 
 result of breeding from the pale-blue males would be to 
 change the whole stock of both sexes to this tint. If, 
 however, variations of the desired tint appeared, which 
 were from the first limited in their development to the 
 male sex, there would not be the least difficulty in making 
 a breed with the two sexes of a different color, as indeed 
 has been effected with a Belgian breed, in which the males 
 alone are streaked with black. In a similar manner, if any 
 variation appeared in a female pigeon, which was from the 
 first sexually limited in its development to the females, it 
 would be easy to make a breed with the females alone thus 
 characterized; but if the variation was not thus originally 
 limited the process would be extremely difficult, perhaps 
 impossible.* 
 
 On the Relation Between the Period of Development of a 
 Character and Its Transmission to One Sex or to Both 
 Sexes. Why certain characters should be inherited by both 
 sexes and other characters by one sex alone, namely, by that 
 sex in which the character first appeared, is in most cases 
 quite unknown. We cannot even conjecture why with cer- 
 tain sub-breeds of the pigeon black strise, though trans- 
 mitted through the female, should be developed in the 
 male alone, while every other character is equally trans- 
 ferred to both sexes. Why, again, with cats, the tortoise- 
 shell color should, with rare exceptions, be developed in 
 the female alone. The very same character, such as defi- 
 cient or supernumerary digits, color-blindness, etc., may 
 
 * Since the publication of the first edition of this work, it has been 
 highly satisfactory to me to find the following remarks (the " Field," 
 Sept., 1872) from so experienced a breeder as Mr. Tegetmeier. 
 After describing some curious cases in pigeons, of the transmission ol 
 color by one sex alone, and the formation of a sub-breed with this 
 character, he says; " It is a singular circumstance that Mr. Darwin 
 should have suggested the possibility of modifying the sexual colors 
 of birds by a course of artificial election. When he did so, he was 
 in ignorance of these facts that 1 have related ; but it is remarkable 
 how very closely he suggested the right method of procedure."
 
 SEXUAL SELECTION. 263 
 
 with mankind be inherited by the males alone of one 
 family, and in another family by the females alone, though 
 in both cases transmitted through the opposite as well as 
 through the same sex.* Although we are thus ignorant, 
 the two following rules seem often to hold good that varia- 
 tions which first appear in either sex at a late period of life 
 tend to be developed in the same sex alone; while varia- 
 tions which first appear early in life in either sex tend to 
 be developed in both sexes. I am, however, far from sup- 
 posing that this is the sole determining cause. As I have 
 not elsewhere discussed this subject, and as it has an impor- 
 tant bearing on sexual selection, I must here enter into 
 lengthy and someAvhat intricate details. 
 
 It is in itself probable that any character appearing at an 
 early age would tend to be inherited equally by both sexes, 
 for the sexes do not differ much in constitution before the 
 power of reproduction is gained. On the other hand, after 
 this power has been gained and the sexes have come to 
 differ in constitution, the gemmules (if I may again use 
 the language of pangenesis) which are cast off from each 
 varying part in the one sex would be much more likely to 
 possess the proper affinities for uniting with the tissues of 
 the same sex and thus becoming developed than with those 
 of the opposite sex. 
 
 I was first led to infer that a relation of this kind exists 
 from the fact that whenever and in whatever manner the 
 adult male differs from the adult female, he differs in the 
 same manner from the young of both sexes. The generality 
 of this fact is quite remarkable; it holds good with almost 
 all mammals, birds, amphibians and fishes; also with many 
 crustaceans, spiders and some few insects, such as certain 
 orthoptera and 'libellulse. In all these cases the variations, 
 through the accumulation of which the male acquired his 
 proper masculine characters, must have occurred at a some- 
 what late period of life; otherwise the young males would 
 have been similarly characterized; and conformably with 
 our rule, the variations are transmitted to and developed in 
 the adult males alone. When, on the other hand, the adult 
 male closely resembles the young of both sexes (these, with 
 rare -exceptions, being alike), he generally resembles the 
 
 * References are given in my " Variation of Animals under Domes- 
 tication," vol. ii, p. 72.
 
 264 THE DESCENT OF MAN. 
 
 adult female; and in most of these cases the variations 
 through which the young and old acquired their present 
 characters, probably occurred, according to our rule, during 
 youth. But there is here room for doubt, for characters 
 are sometimes transferred to the offspring at an earlier age 
 than that at which they first appeared iu the parents, so 
 that the parents may have varied when adult and have 
 transferred their characters to their offspring while young. 
 There are, moreover, many animals in which the two sexes 
 closely resemble each other, and yet both differ from their 
 young; and here the characters of the adults must have 
 been acquired late in life; nevertheless, these characters, in 
 apparent contradiction to our rule, are transferred to both 
 sexes. We must not, however, overlook the possibility or 
 even probability of successive variations of the same nature 
 occurring, under exposure to similar conditions, simul- 
 taneously in both sexes at a rather late period of life; and 
 in this case the variations would be transferred to the off- 
 spring of both sexes at a corresponding late age; and there 
 would then be no real contradiction to the rule that varia- 
 tions occurring late in life are transferred exclusively to the 
 sex in which they first appeared. This latter rule seems to 
 hold true more generally than the second one, namely, that 
 variations which occur in either sex early in life tend to be 
 transferred to both sexes. As it was obviously impossible 
 even to estimate in how large a number of cases throughout 
 the animal kingdom these two propositions held good, it 
 occurred to me to investigate some striking or crucial 
 instances and to rely on the result. 
 
 An excellent case for investigation is afforded by the 
 deer family. In all the species but one the horns are 
 developed only in the males, though certainly transmitted 
 through the females and capable of abnormal development 
 in them. In the reindeer, on the other hand, the female 
 is provided with horns; so that in this species the horns 
 ought, according to our rule, to appear early in life, long 
 before the two sexes are mature and have come to differ 
 much in constitution. In all the other species the horns 
 ought to appear later in life, which would lead to their 
 development in that sex alone in which they first appeared 
 in the progenitor of the whole family. Now in seven 
 species belonging to distinct sections of the family and 
 inhabiting different regions in which the stags alone bear
 
 SEXUAL SELECTION. 265 
 
 horns, I find that the horns first appear at periods varying 
 from nine months after birth in the roebuck to ten, twelve 
 or even more months in the stags of the six other and 
 larger species.* But with the reindeer the case is widely 
 different; for, as I hear from Prof. Nilsson, who kindly 
 made special inquiries for me in Lapland, the horns appear 
 in the young animals within four or five weeks after birth, 
 and at the same time in both sexes. So that here we have 
 a structure developed at a most unusually early age in one 
 species of the family and likewise common to both sexes in 
 this one species alone. 
 
 In several kinds of antelopes only the males are provided 
 with horns, while in the greater number both sexes bear 
 horns. With respect to the period of development, Mr. 
 Blyth informs me that there was at one time in the Zoo- 
 logical Gardens a young koodoo (Ant. strepsiceros) of 
 which the males alone are horned, and also the young of a 
 closely allied species, the eland (Ant. oreas), in which both 
 sexes are horned. Now it is in strict conformity with our 
 rule that in the young male koodoo, although ten months 
 old, the horns were remarkably small, considering the size 
 ultimately attained by them; while in the young male 
 eland, although only three months old, the horns were 
 already very much larger than in the koodoo. It is also a 
 noticeable fact that in the prong-horned antelope f only a 
 few of the females, about one in five, have horns, and 
 these are in a rudimentary state, though sometimes above 
 four inches long; so that as far as concerns the possession 
 of horns by the males alone, this species is in an inter- 
 mediate condition and the horns do not appear until about 
 five or six months after birth. Therefore in comparison 
 
 * I am much obliged to Mr. Cupples for having made inquiries for 
 me in regard to the Roebuck and Red Deer of Scotland from Mr. 
 Robertson, the experienced head-forester to the Marquis of Breadal- 
 bane. In regard to Fallow-deer, I have to thank Mr. Eyton and 
 otters for information. For the Cerous dices of North America, see 
 "Land and Water," 1868, pp. 221, 254; and for the G. Vi^ginianus 
 and stronyyloceros of the same continent, see J. D. Caton, in '' Ottawa 
 Acacl. of Nat. Sc.," 1868, p. 13. For Genus EUli of Pegu, see Lieut. 
 Beavan, "Proc. Zoolog. Soc.," 1867, p. 762. 
 
 f Antilocapra Americana. I have to thank Dr. Canfield for infor- 
 mation with respect to the horns of the female; see also his paper in 
 "Proc. Zoolog. Soc.." 1866, p. 109. Also Owen, " Anatony of Verte- 
 brates," vol. iii, p. 627.
 
 2G6 THE DESCENT OF MAN. 
 
 with what little we know of the development of the horns 
 in other antelopes and from what we do know with respect 
 to the horns of deer, cattle, etc., those of the prong-horned 
 antelope appear at an intermediate period of life that is 
 not very early, as in cattle and sheep, nor very late, as in 
 the larger deer and antelopes. The horns of sheep, goats 
 and cattle which are well developed in both sexes, though 
 not quite equal in size, can be felt, or even seen, at birth 
 or soon afterward.* Oar rule, however, seems to fail in 
 some breeds of sheep, for instance merinos, in which the 
 rams alone are horned; for I cannot find on inquiry f that 
 the horns are developed later in life in this breed than in 
 ordinary sheep in which both sexes are horned. But with 
 domesticated sheep the presence or absence of horns is not 
 a firmly fixed character; for a certain proportion of the 
 merino ewes bear small horns, and some of the rams are 
 hornless; and in most breeds hornless ewes are occasionally 
 produced. 
 
 Dr. W. Marshall has lately made a special study of the 
 protuberances so common on the heads of birds, J and he 
 comes to the following conclusion: that with those speciea 
 in which they are confined to the males, they are developed 
 late in life; whereas with those species in which they are 
 common to the two sexes, they are developed at a very 
 early period. This is certainly a striking confirmation oi 
 my two laws of inheritance. 
 
 In most of the species of the splendid family of the 
 pheasants, the males differ conspicuously from the females, 
 and they acquire their ornaments at a rather late period of 
 
 *I have been assured that the horns of the sheep in North Wales 
 can always be felt, and are sometimes even an inch in length at 
 birth. Youatt says ("Cattle," 1834, p. 277), that the prominence of 
 the frontal bone in cattle penetrates the cutis at birth, and that the 
 li.Hiiy matter is soon formed over it. 
 
 f I am greatly indebted to Prof. Victor Carus for having made 
 inquiries for me, from the highest authorities, with respect to the 
 merino sheep of Saxony. On the Guinea coast of Africa there is. 
 however, a breed of sheep in which, as with merinos, the rams alone 
 bear horns; and Mr. Winwood Reade informs me that in one case 
 observed by him, a young ram, born on Feb. 10th, first showed horns 
 on March 6th, so that in this instance, in conformity with rule, the 
 development of the horns occurred at a later period of life than in 
 Welsh sheep, in which both sexes art- honied. 
 
 J " Ueber die knSchermen Schadel hooker der Vonel " in the " Nie- 
 derhmdischen Archiv. fur Zoologie," Baud 1, Heft 2, 1872.
 
 SEXUAL SELECTION. 267 
 
 life. The eared pheasant (Crossoptilon aurifnm), however, 
 offers a remarkable exception, for both sexes possess the 
 fine caudal plumes, the large ear-tufts and the crimson 
 velvet about the head; I find that all these characters 
 appear very early in life in accordance with rule. The 
 adult male can, however, be distinguished from the adult 
 female by the presence of spurs; and, conformably with 
 our rule, these do not begin to be developed before the age 
 of six months, as I am assured by Mr. Bartlett, and even 
 at this age the two sexes can hardly be distinguished. * The 
 male and female peacock differ conspicuously from each 
 other in almost every part of their plumage, except in the 
 elegant head-crest, which is common to both sexes; and this 
 is developed very early in life, long before the other orna- 
 ments which are confined to the male. The wild duck 
 offers an analogous case, for the beautiful green speculum 
 on the wings is common to both sexes, though duller and 
 somewhat smaller in the female, and it is developed early 
 in life, while the curled tail-feathers and other ornaments 
 of the male are developed later, f Between such extreme 
 cases of close sexual resemblance and wide dissimilarity, as 
 those of the Crossoptilon and peacock, many intermediate 
 
 *In the common peacock (Pavo cristatus) the male alone possesses 
 spurs, while both sexes of the Java Peacock (P. muticiis) offer the 
 unusual case of being furnished with spurs. Hence I fully expected 
 that in the latter species they would have been developed earlier in 
 life than in the common peacock; but M. Hegt of Amsterdam informs 
 me, that with young birds of the previous year, of both species, 
 compared on April 23, 1869, there was no difference in the develop- 
 ment of the spurs. The spurs, however, were as yet represented 
 merely by slight knobs or elevations. I presume that I should have 
 been informed if any difference in the rate of development had been 
 observed subsequently. 
 
 f In some other species of the Duck family the speculum differs in 
 a greater degree in the two sexes; but I have not been able to dis- 
 cover whether its full development occurs later in life in the males of 
 such species, than in the males of the common duck, as ought to be the 
 case according to our rule. With the allied Mergus cucullatus we 
 have, however, a case of this kind: the two sexes differ conspicu- 
 ously in general plumage, and to a considerable degree in the specu- 
 lum* which is pure white in the male and grayish-white in the 
 female. Now the young males at first entirely resemble the females, 
 and have a grayish-white speculum, which becomes pure white at an 
 earlier age than that at which the adult male acquires his other and 
 more strongly-marked sexual differences: see Audubon, " Ornitholo- 
 gical Biography," vol. iii. 1835, pp. 24&-250.
 
 268 THE DESCENT OF MAN. 
 
 ones could be given, in which the characters follow our two 
 rules in their order of development. 
 
 As most insects emerge from the pupal state in a mature 
 condition it is doubtful whether the period of development 
 can determine the transference of their characters to one or 
 to both sexes. But we do not know that the colored scales, 
 for instance, in two species of butterflies, in one of which 
 the sexes differ in color, while in the other they are alike, 
 are developed at the same relative age in the cocoon. Nor 
 do we know whether all the scales are sinmltaneously devel- 
 oped on the wings of the same species of butterfly, in 
 which certain colored marks are confined to one sex, while 
 others are common to both sexes. A difference of this kind 
 in the period of development is not so improbable as it may 
 at first appear; for with the Orthoptera, which assume their 
 adult state, not by a single metamorphosis, but by a suc- 
 cession of moults/ the young males of some species at first 
 resemble the females, and acquire their distinctive mascu- 
 line characters only at a later moult. Strictly analogous 
 cases occur at the successive moults of certain male 
 crustaceans. 
 
 We have as yet considered the transference of characters, 
 relatively to their period of development, only in species in 
 a natural state; we will now turn to domesticated animals, 
 and first touch on monstrosities and diseases. The presence 
 of supernumerary digits, and the absence of certain 
 phalanges, must be determined at an early embryonic 
 period the tendency to profuse bleeding is at least con- 
 genital, as is probably colox-blinduess yet these peculiar- 
 ities, and other similar ones, are often limited in their 
 transmission to one sex; so that the rule that characters, 
 developed at an early period, tend to be transmitted to both 
 Bexes, here wholly fails. But this rule, as before remarked, 
 does not appear to be nearly so general as the converse one, 
 namely, that characters which appear late in life in one sex 
 are transmitted exclusively to the same sex. From the 
 fact of the above abnormal peculiarities becoming attached 
 to one sex, long before the sexual functions are active, we 
 may infer that there must be some difference between the 
 sexes at an extremely early age. With respect to sexually- 
 limited diseases we know too little of the period at which 
 they originate to draw any safe conclusion. Gout, however, 
 seems to fall under our rule, for it is generally caused by
 
 SEXUAL SELECTION. 269 
 
 intemperance during manhood, and is transmitted from the 
 father to his sons in a much more marked manner than to 
 his daughters. 
 
 In the various domestic breeds of sheep, goats, and 
 cattle the males differ from their respective females in 
 the shape or development of their horns, forehead, mane, 
 dewlap, tail and hump on the shoulders; and these pecu- 
 liarities, in accordance with our rule, are not fully devel- 
 oped until a rather late period of life. The sexes of dogs 
 do not differ, except that in certain breeds, especially in 
 the Scotch deer-hound, the male is much larger and heavier 
 than the female; and, as we shall see in a future chapter, 
 the male goes on increasing in size to an unusually late 
 period of life, which, according to rule, will account for 
 his increased size being transmitted to his male offspring 
 alone. On the other hand, the tortoise-shell color, which 
 is confined to female cats, is quite distinct at birth, and 
 this case violates the rule. There is a breed of pigeons in 
 which the males alone are streaked with black, and the 
 streaks can be detected even in the nestlings; but they 
 become more conspicuous at each successive moult, so that 
 this case partly opposes and partly supports the rule. With 
 the English carrier and Pouter pigeons, the full develop- 
 ment of the wattle and crop occurs rather late in life, 
 and conformably with the rule, these characters are trans- 
 mitted in full perfection to the males alone. The follow- 
 ing cases perhaps come within the class previously alluded 
 to, in which both sexes have varied in the same manner at 
 a rather late period of life, and have consequently trans- 
 ferred their new characters to both sexes at a corresponding 
 late period^ and if so, these cases are not opposed to our 
 rule; there exist sub-breeds of the pigeon, described by 
 Neumeister,* in which both sexes change their color during 
 two or three moults (as is likewise the case with the Almond 
 Tumbler); nevertheless, these changes, though occurring 
 rather late in life, are common to both sexes. One variety 
 of the canary-bird, namely, the London Prize, offers a 
 nearly analogous case. 
 
 With the breeds of the fowl the inheritance of various 
 characters by one or both sexes seems generally determined 
 
 *"Das Qanze der Taubenzucht," 1837, ss. 21, 24 For the case of 
 the streaked pigeons, see Dr. Chapuis, " Le pigeon voyageur Beige," 
 J865, p. 87.
 
 270 THE DESCENT OF MAN. 
 
 by the period at which such characters are developed. Thus 
 in all the many breeds in which the adult male differs 
 greatly in color from the female, as well as from the wild 
 parent-species, he differs also from the young male, so thafe 
 the newly-acquired characters must have appeared at a 
 rather late period of life. On the other hand, in most of 
 the breeds in which the two sexes resemble each other, the 
 young are colored in nearly the same manner as their 
 parents, and this renders it probable that their colors first 
 appeared early in life. We have instances of, this fact in 
 all black and white breeds, in which the young and old of 
 both sexes are alike; nor can it be maintained that there is 
 something peculiar in a black or Avhite plumage, which 
 leads to its transference to both sexes; for the males alone 
 of many natural species are either black or white, the 
 females being differently colored. With the so-called 
 Cuckoo sub-breeds of the fowl in which the feathers are 
 transversely penciled with dark stripes, both sexes and the 
 chickens are colored in nearly the same manner. The 
 laced plumage of the Sebright bantam is the same in both 
 sexes, and in the young chickens the wing-feathers are dis- 
 tinctly,, though imperfectly, laced. Spangled Hamburgs, 
 however, offer a partial exception ; for the two sexes, 
 though not quite alike, resemble each other more closely 
 than do the sexes of the aboriginal parent-species; yet they 
 acquire their characteristic plumage late in life, for the 
 chickens are distinctly penciled. With respect to other 
 characters besides color, in the wild-parent species and in 
 most of the domestic breeds the males alone possess a well- 
 developed comb; but in the young of the Spanish fowl it 
 is largely developed at a very early age, and, in accordance 
 with this early development in the male, it is of unusual 
 size in the adult female. In the game breeds pugnacity is 
 developed at a wonderfully early age, of which curious 
 proofs could be given; and this character is transmitted to 
 both sexes, so that the hens, from their extreme pugnacity, 
 j?re now generally exhibited in separate pens. With the 
 Polish breeds the bony protuberance of the skull which 
 supports the crest is partially developed even before the 
 chickens are hatched, and the crest itself soon begins to 
 grow, though at first feebly;* and in this breed the adults 
 
 * For full particulars and references on all these points respecting 
 the several breeds of the fowl, see " Variation of Animals and Plants
 
 SEXUAL SELECTION. 271 
 
 of both sexes are characterized by a great bony protuber- 
 ance and an immense crest. 
 
 Finally, from what we hare now seen of the relation 
 which exists in many natural species and domesticated 
 races between the period of the development of their char- 
 acters and the manner of their transmission for example, 
 the striking fact of the early growth of the horns in the 
 reindeer, in which both sexes bear horns, in comparison 
 with their much later growth in the other species in which , 
 the male alone bears horns we may conclude that one, 
 though not the sole cause of characters being exclusively 
 inherited by one sex, is their development at a late age. 
 And secondly, that one, though apparently a less effective 
 cause of characters being inherited by both sexes, is their 
 development at an early age, while the sexes differ but 
 little in constitution. It appears, however, that some dif- 
 ference must exist between the sexes even during a very 
 early embryonic period, for characters developed at this 
 age not rarely become attached to one sex. 
 
 Summary and Concluding Remarks. From the forego- 
 ing discussion on the various laws of inheritance we learn 
 that the characters of the parents often, or even generally, 
 tend to become developed in the offspring of the same sex, 
 at the same age, and periodically at the same season of the 
 year in which they first appeared in the parents. But 
 these rules, owing to unknown causes, are far from being 
 fixed. Hence, during the modification of a species the 
 successive changes may readily be transmitted in different 
 ways; some to one sex and some to both; some to the off- 
 spring at one age and some to the offspring at all ages. 
 Not only are the laws of inheritance extremely complex, 
 but so are the causes which induce and govern variability. 
 The variations thus induced are preserved and accumulated 
 by sexual selection, which is in itself an extremely complex 
 affair, depending as it does on the ardor of love, the cour- 
 age and the rivalry of the males as well as on the powers 
 of perception, the taste and will of the female. Sexual 
 selection will also be largely dominated by natural selection 
 
 under Domestication," vol. i, pp. 250, 256. In regard to the higher 
 animals, the sexual differences which have arisen under domestica- 
 tion are described in the same work under the head of each species.
 
 272 THE DESCENT OF MAN 
 
 tending toward the general welfare of the species. Hence 
 the manner in which the individuals of either or both 
 sexes have been affected through sexual selection cannot 
 fail to be complex in the highest degree. 
 
 When variations occur late in life in one sex and are 
 transmitted to the same sex at the same age the other sex 
 and the young are left unmodified. When they occur late 
 in life but are transmitted to botli sexes at the same age 
 the young alone are left unmodified. Variations, however, 
 may occur at any period of life in one sex or in both, and 
 be transmitted to both sexes at all ages, and then all the 
 individuals of the species are similarly modified. In the 
 following chapters it will be seen that all these cases fre- 
 quently occur in nature. 
 
 Sexual selection can never act on any animal before the 
 age for reproduction arrives. From the great eagerness of 
 the male it has generally acted on this sex and not on the 
 females. The males have thus become provided with 
 weapons for fighting with their rivals, with organs for dis- 
 covering and securely holding the female and for exciting 
 or charming her. When the sexes differ in these respects 
 it is also, as we have seen, an extremely general law that 
 the adult male differs more or less from the young male; 
 and we may conclude from this fact that the successive 
 variations by which the adult male became modified did 
 not generally occur much before the age for reproduction. 
 Whenever some or many of the variations occurred eurlv in 
 life the young males would partake more or less of the 
 characters of the adult males; and differences of this kind 
 between the old and young males may be observed in many 
 species of animals. 
 
 It is probable that young male animals have often tended 
 to vary in a manner which would not only have been of no 
 use to them at an early age, but would have been actually 
 injurious as by acquiring bright colors which would 
 render them conspicuous to their enemies, or by acquiring 
 structures, such as great horns, which would expend much 
 vital force in their development. Variations of this kind 
 occurring in the young males would almost certainly be 
 eliminated through natural selection. With the adult and 
 experienced males, on the other hand, the advantages 
 derived from the acquisition of such characters would 
 more than counterbalance some exposure to danger and 
 some loss of vital force.
 
 SEXUAL SELECTION. 273 
 
 As variations which give to the male a better chance of 
 conquering other males or of finding, securing or charm- 
 ing the opposite sex would, if they happened to arise in the 
 female, be of no service to her, they would not be pre- 
 served in her through sexual selection. We have also good 
 evidence with domesticated animals that variations of all 
 kinds are, if not carefully selected, soon lost through inter- 
 crossing and accidental deaths. Consequently in a state 
 of nature if variations of the above kind chanced to arise 
 in the female line, and to be transmitted exclusively in 
 this line, they would be extremely liable to be lost. If, 
 however, the females varied and transmitted their newly 
 acquired characters to their offspring of both sexes the 
 characters which were advantageous to the males would be 
 preserved by them through sexual selection, and the two 
 sexes would in consequence be modified in the same man- 
 ner, although such characters were of no use to the 
 females; but I shall hereafter have to recur to these more 
 intricate contingencies. Lastly, the females may acquire 
 and apparently have often acquired by transference char- 
 acters from the male sex. 
 
 As variations occurring late in life and transmitted to 
 one sex alone have incessantly been taken advantage of and 
 accumulated through sexual selection in relation to the 
 reproduction of the species; therefore it appears, at first 
 sight, an unaccountable fact that similar variations have 
 not frequently been accumulated through natural selection, 
 in relation to the ordinary habits of life. If this had 
 occurred, the two sexes would often have been differently 
 modified, for the sake, for instance, of capturing prey or 
 of escaping from danger. Differences of this kind between 
 the two sexes do occasionally occur, especially in the lower 
 classes. But this implies that the two sexes follow different 
 habits in their struggles for existence, which is a rare cir- 
 cumstance with the higher animals. The case, however, is 
 widely different with the reproductive functions, in which 
 respect the sexes necessarily differ. For variations in 
 structure, which are related to these functions, have often 
 proved of value to one sex, and from having arisen at a late 
 period^ of life, have been transmitted to one sex alone; and 
 such variations, thus preserved and transmitted, have given 
 rise to secondary sexual characters. 
 
 In the following chapters I shall treat of the secondary
 
 274 THE DESCENT OF MAN. 
 
 sexual characters in animals of all classes, and shall 
 endeavor in each case to apply the principles explained in 
 the present chapter. The lowest classes will detain us for 
 a very short time, but the higher animals, especially birds, 
 must be treated at considerable length. It should be lorne 
 in mind that for reasons already assigned I intend to give 
 only a few illustrative instances of the innumerable 
 structures by the aid of which the male finds the female, 
 or, when found, holds her. On the other hand, all 
 structures and instincts ~by the aid of which the male con- 
 quers other males, and by which he allures or excites the 
 female, will be fully discussed, as these are in many ways 
 the most interesting. 
 
 SUPPLEMENT ON THE PROPORTIONAL NUMBERS OF THE 
 TWO SEXES IN ANIMALS BELONGING TO VARIOUS 
 CLASSES. 
 
 As no one, as far as I can discover, has paid attention to 
 the relative numbers of the two sexes throughout the 
 animal kingdom, I will here give such materials as I have 
 been able to collect, although they are extremely imperfect. 
 They consist in only a few instances of actual enumeration 
 and the numbers are not very large. As the proportions 
 are known with certainty only in mankind, I will first give 
 them as a standard of comparison. 
 
 Man. In England during ten years (from 1857 to 1866) 
 the average number of children born alive yearly was 
 707,120, in the proportion of 104.5 males to 100 females. 
 But in 1857 the male births throughout England were as 
 105.2, and in 1865 as 104 to 100. Looking to separate 
 districts, in Buckinghamshire (where about 5,000 children 
 are annually born) the mean proportion of male to female 
 births during the whole period of the above ten years was 
 as 102.8 to 100; while in N. Wales (where the average 
 annual births are 12,873) it was as high as 106.2 to 100. 
 Taking a still smaller district, viz., Rutlandshire (where 
 the annual births average only 739), in 1864 the male 
 births were as 114.6, and in 1862 as only 97 to 100; but 
 even in this small district the average of the 7,385 births 
 during the whole ten years was as 104.5 to 100; that
 
 PROPORTION OF THE SEXES. 275 
 
 is in the same ratio as throughout England.* The propor- 
 tions are sometimes slightly disturbed by unknown causes; 
 thus Prof. Faye states " that in some districts of Norway 
 there has been during a decennial period a steady deficiency 
 of boys, while in others the opposite condition has existed/' 
 In France, during forty-four years, the male to the female 
 births have been as 106.2 to 100; but during this period it 
 has occurred five times in one department and six times 
 in another, that the female births have exceeded the males. 
 In Russia the average proportion is as high as 108.9, and 
 in Philadelphia, in the United States, as 110.5 to 100. f The 
 average for Europe, deduced by Bickes from about 70,000,- 
 000 births, is 106 males to 100 females. On the other 
 hand, with white children born at the Cape of Good Hope, 
 the proportion of males is so low as to fluctuate during suc- 
 cessive years between 90 and 99 males for every 100 females. 
 It is a singular fact that with Jews the proportion of male 
 births is decidedly larger than with Christians ; thus in 
 Prussia the proportion is as 113, in Breslau as 114, and in 
 Livonia as 120 to 100; the Christian births in these coun- 
 tries being the same as usual, for instance, in Livonia as 
 104 to 100. J 
 
 Prof. Faye remarks that " a still greater preponderance 
 of males would be met with, if death struck both sexes in 
 equal proportion in the womb and during birth. But the 
 fact is, that for every 100 still-born females we have in 
 several countries from 134.6 to 144.9 still-born males. 
 During the first four or five years of life, also, more male 
 children die than females, for example in England, during 
 the first year, 126 boys die for every 100 girls a proportion 
 which in France is still more unfavorable. " Dr. Stock- 
 
 * " Twenty-ninth Annual Report of the Rsgistrar-General for 
 1866." In this report (p. 12) a special decennial table is given. 
 
 f For Norway and Russia, see abstract of Prof. Faye's researches 
 in "British and Foreign Medico-Chirurg. Review," April, 1867, pp. 
 343,345. For France, the "Annuaire pour 1'An, 1867," p. 213. 
 For Philadelphia, Dr. Stockton Hough, " Social Science Assoc.," 
 1874. For the Cape of Good Hope, Quetelet as quoted by Dr. H. H. 
 Zouteveen in the Dutch translation of this work (vol. i, p. 417), where 
 much information is given on the proportion of the sexes. 
 
 Jin regard to the Jews, see M. Thury, " La Loi de Production des 
 Sexes," 1863, p. 25. 
 
 " British and Foreign Medico-Chirurg. Review," April, 1867, p. 
 343. Dr. Stark also remarks (" Tenth Annual Report of Births,
 
 276 THE DESCENT OF MAN. 
 
 ton Hough accounts for these facts in part by the more 
 frequent defective development of males than of females. 
 We have before seen that the male sex is more variable in 
 structure than the female ; and variations in important 
 organs would generally be injurious. But the size of the 
 body, and especially of the head, being greater in male 
 than female infants is another cause; for the males are thus 
 more liable to be injured during parturition. Consequently 
 the still-born males are more numerous; and as a highly 
 competent judge, Dr. Crichton Browne,* believes male 
 infants often suffer in health for some years after birth. 
 Owing to this excess in the death-rate of male children, 
 both at birth and for some time subsequently, and owing to 
 the exposure of grown men to various dangers and to their 
 tendency to emigrate, the females in all old-settled coun- 
 tries, where statistical records have been kept,f are found 
 to preponderate considerably over the males. 
 
 It seems at first sight a mysterious fact that in different 
 nations, under different conditions and climates, in Naples, 
 Prussia, Westphalia, Holland, France, England and the 
 United States, the excess of male over female births is less 
 when they are illegitimate than when legitimate. J This 
 has been explained by different writers in many different 
 ways, as from the mothers being generally young, from the 
 large proportion of first pregnancies, etc. But we have 
 
 Deaths, etc., in Scotland," 1867, p. 28) that "These examples may 
 suffice to show that, at almost every stage of life, the males in Scot- 
 land have a greater liability to death and a higher death-rate than 
 the females. The fact, however, of this peculiarity being most 
 strongly developed at that infantile period of life when the dress, 
 food and general treatment of both sexes are alike, seems to prove 
 that the higher male death-rate is an impressed, natural and consti- 
 tutional peculiarity due to sex alone." 
 
 * " West Riding Lunatic Asylum Reports," vol. i, 1871, p. 8. Sir 
 J. Simpson has proved that the head of the male infant exceeds that 
 of the female by three-eighths of an inch in circumference and by 
 one eighth in transverse diameter. Quetelet has shown that woman 
 is born smaller than man ; see Dr. Duncan, " Fecundity, Fertility, 
 Sterility," 1871, p. 382. 
 
 f With the savage Guaranys of Paraguay, according to the accu- 
 rate Azara (" Voyages dans 1'Amerique merid.," torn, ii, 1809, pp. 60, 
 179) the women are to the men in the porportion of 14 to 13. 
 
 fBabbage, "Edinburgh Journal of Science," 1829, vol. i, p. 88; 
 also p. 90, on still-born children. On illegitimate children in En- 
 gland, see " Report of Registrar -General for 1866," p. 15.
 
 PROPORTION OF THE SEXES. 277 
 
 seen that male infants, from the large size of their heads, 
 suffer more than female infants during parturition; and as 
 the mothers of illegitimate children must be more liable 
 than other women to undergo bad labors, from various 
 causes, such as attempts at concealment by tight lacing, 
 hard work, distress of mind, etc., their male infants would 
 proportionately suffer. And this probably is the most effi- 
 cient of all the causes of the proportion of males to females 
 born alive being less among illegitimate children than 
 among the legitimate. With most animals the greater size 
 of the adult male than of the female is due to the stronger 
 males having conquered the weaker in their struggles for 
 the possession of the females, and no doubt it is owing to 
 this fact that the two sexes of at least some animals differ 
 in size at birth. Thus we have the curious fact that we 
 may attribute the more frequent deaths of male than 
 female infants, especially among the illegitimate, at least 
 in part to sexual selection. 
 
 It has often been supposed that the relative age of the 
 two parents determines the sex of the offspring; and Prof. 
 Leuckart * has advanced what he considers sufficient evi- 
 dence, with respect to man and certain domesticated 
 animals, that this is one important though not the sole 
 factor in the result. So again the period of impregnation 
 relatively to the state of the female has been thought by 
 some to be the efficient cause; but recent observations dis- 
 countenance this belief. According to Dr. Stockton 
 Hough, f the season of the year, the poverty or wealth of 
 the parents, residence in the country or in cities, the cross- 
 ing of foreign immigrants, etc., all influence the proportion 
 of the sexes. With mankind, polygamy has also been sup- 
 posed to lead to the birth of a greater proportion of female 
 infants; but Dr. J. Campbell J carefully attended to this 
 subject in the harems of Siam, and concludes that the pro- 
 portion of male to female births is the same as from 
 monogamous unions. Hardly any animal has been rendered 
 so highly polygamous as the English race-horse., and we 
 shall immediately see that his male and female offspring 
 
 * Leuckart, in Wagner, " Handworterbuch der Phys.," B. iv, 1853, 
 . s. 774. - 
 
 f Social Science Assoc. of Philadelphia, 1874 
 t" Anthropological Review," April, 1870, P- 108.
 
 278 TEE DESCENT OF MAN. 
 
 are almost exactly equal in number. I will now give the 
 facts which I have collected with respect to the proportional 
 numbers of the sexes of various animals; and will then 
 briefly discuss how far selection Las come into play in- 
 determining the result. 
 
 Horses. Mr. Tegetineier has been so kind as to tabulate for me 
 from the " Racing Calendar " the births of race-horses during a 
 period of twenty-one years, viz., from 1846 to 1867; 1849 being 
 omitted, as no returns were that year published. The total births 
 were 25,560,* consisting of 12,763 males and 12,797 females, or in the 
 proportion of 99.7 males to 100 females. As these numbers are tol- 
 erably large, and as they are drawn from all parts of England, dur- 
 ing several years, we may with much confidence conclude that with 
 the domestic horse, or at least with the race-horse, the two sexes are 
 produced in almost equal numbers. The fluctuations in the propor- 
 tions during successive years are closely like those which occur with 
 mankind, when a small and thinly populated area is considered; thus 
 in 1856 the male horses were as 107.1, and in 1867 as only 92.6 to 
 100 females. In the tabulated returns the proportions vary in cycles, 
 for the males exceeded the females during six successive years; and 
 the females exceeded the males during two periods each of four 
 years; this, however, may be accidental; at least I can detect nothing 
 of the kind with man in the decennial table in the Registrar's Report 
 for 1866. 
 
 Dogs. During a period of twelve years, from 1857 to 1868, the 
 births of a large number of greyhounds throughout England were 
 sent to the "Field" newspaper; and I am again indebted to Mr. 
 Tegetmeier for carefully tabulating the results. The recorded births 
 were 6,878, consisting of 3,605 males and 3,273 females, that is, in 
 the proportion of 110.1 males to 100 females. The greatest fluctua- 
 tions occurred in 1864, when the proportion was as 95.3 males, and 
 in 1867, as 116.3 males to 100 females. The above average propor- 
 tion of 110.1 to 100 is probably nearly correct in the case of the grey- 
 hound, but whether it would hold with other domesticated breeds is 
 in some degree doubtful. Mr. Cupples has inquired from several 
 great breeders of dogs, and finds that all without exception believe 
 that females are produced in excess; but he suggests that this belief 
 may have arisen from females being less valued, and from the 
 consequent disappointment producing a stronger impression on the 
 mind 
 
 Sheep The sexes of sheep are not ascertained by agriculturists 
 until several months after birth, at the period when the males are 
 
 * During eleven years a record was kept of the number of mares which 
 proved barren or prematurely slipped their foals ; and it deserves notice, as 
 showing how infertile these highly nurtured and rather closely intorbred ani- 
 mals have become, that not far from one-third of the mares failed to produce 
 living foals. Thus during 1866, 809 male colts and 816 female colts were born, 
 and 743 mares failed to produce offspYing. During 1867, 83tt males and 902 
 females were bora, and 794 mares failed.
 
 PROPORTION OF THE SEXES. 279 
 
 castrated; so that the following returns do not give the proportions 
 at birth. Moreover, I find that several great breeders in Scotland, 
 who annually raise some thousand sheep, are firmly convinced that 
 a larger proportion of males than of females die during the first year 
 or two. Therefore the proportion of males would be somewhat larger 
 at birth than at the age of castration. This is a remarkable coinci- 
 dence with what, as we have seen, occurs with mankind, and both 
 cases probably depend on the same cause. I have received returns 
 from four gentlemen in England who have bred Lowland sheep, 
 chiefly Leicesters, during the last ten to sixteen years; they amount 
 altogether to 8,965 births, consisting of 4,407 males and 4,558 females; 
 that is in the proportion of 96.7 males to 100 females. With respect 
 to Cheviot and black-faced sheep bred in Scotland, I have received 
 returns from six breeders, two of them on a large scale, chiefly for 
 the years 1867-1869, but some of the returns extend back to 1862. 
 The total number recorded amounts to 50,685, consisting of 25,071 
 males and 25,614 females, or in the proportion of 97.9 males to 100 
 females. If we take the English and Scotch returns together, the 
 total number amounts to 59,650, consisting of 29,478 males and 30,172 
 females, or as 97,7 to 100. So that with sheep at the age of castra- 
 tion the females are certainly in excess of the males, but probably 
 this would not hold good at birth.* 
 
 Cattle. I have received returns from nine gentlemen of 982 births, 
 too few to be trusted ; these consisted of 477 bull-calves and 505 
 cow-calves; i. e., in the proportion of 94.4 males to 100 females. 
 The Kev. W. D. Fox informs me that in 1867 out of 34 calves born 
 on a farm in Derbyshire only one was a bull. Mr. Harrison Weir 
 has inquired from several breeders of pigs, and most of them esti- 
 mate the male to the female births as about 7 to 6. This same 
 gentleman has bred rabbits for many years, and has noticed that a 
 far greater number of bucks are produced than does. But estima- 
 tions are of little value. 
 
 Of mammalia in a state of nature I have been able to learn very 
 little. In regard to the common rat, I have received conflicting 
 statements. Mr. R. Elliot, of Laighwood, informs me that a rat- 
 catcher assured him that he had always found the males in great 
 excess, even with the young in the nest. In consequence of this, 
 Mr. Elliot himself subsequently examined some hundred old ones 
 and found the statement true. Mr. F. Buckland has bred a large 
 number of white rats, and he also believes that the males greatly 
 exceed the females. In regard to moles, it is said that " the males 
 are much more numerous than the females ;" \ and as the catching 
 of these animals is a special occupation, the statement may perhaps 
 be trusted. Sir A. Smith, in describing an antelope of S. Africa^ 
 
 * I am much indebted to Mr. Cupples for having procured for me the above 
 returns from Scotland, as well as some of the following returns on cattle. Mr. 
 R. Elliot, of Laighwood, first called my attention to the premature deaths of 
 the males a statement subsequently confirmed by Mr. Aitchison and others. 
 To this latter gentleman, and to Mr. Payan, I owe my thanks for large returns 
 as to sheep. 
 
 tBell, " History of British Quadrupeds," p. 100. 
 
 * " Illustrations of the Zoology of S. Africa," 1849, pi. 2ft
 
 eggs 
 Weir 
 
 280 THE DESCENT OF MAN. 
 
 (Kobus ellipsiprymnus), remarks, that in the herds of this and othei 
 species, the males are few in number compared with the females ; 
 the natives believe that they are born in this proportion; others 
 believe that the younger males are expelled from the herds, and Sir 
 A. Smith, says, that though he has himself never seen herds con- 
 sisting of young males alone, others affirm that this does occur. It 
 appears probable that the young when expelled from the herd would 
 often fall a prey to the many beasts of prey of the country. 
 
 Birds. With respect to the fowl, I have received only one 
 account, namely, that out of 1,001 chickens of a highly-bred stock of 
 Cochins, reared during eight years by Mr. Stretch, 487 proved males 
 and 514 females; i. e., as 94.7 to 100. In regard to domestit pigeons 
 there is good evidence either that the males are produced in excess, 
 or that they live longer ; for these birds invariably pair, and singl 
 males, as Mr. Tegetrneier informs me, can always be purchased 
 cheaper than females. Usually the two birds reared from the two 
 laid in the same nest are a male and a female; but Mr. Harrison 
 
 eir, who has been so large a breeder, says that he has often bred 
 two cocks from the same nest, and seldom two hens ; moreover, the 
 hen is generally the weaker of the two and more liable to perish. 
 
 With respect to birds in a state of nature, Mr. Gould and others * 
 are convinced that the males are generally the more numerous ; and 
 as the young males of many species resemble the females, the latter 
 would naturally appear to be the more numerous. Large numbers 
 of pheasants are reared by Mr. Baker of Leadenhall from eggs laid 
 by wild birds, and he informs Mr. Jenner Weir that four or five 
 males to one female are generally produced. An experienced 
 observer remarks,! tua * i n Scandinavia the broods of the capercailzie 
 and black-cock contain more males than females ; and that with the 
 Dal ripa (a kind of ptarmigan) more males than females attend the 
 leks or places of courtship ; but this latter circumstance is accounted 
 for by some observers by a greater number of hen birds being 
 killed by vermin. From various facts given by White of Selborne,; 
 it seems clear that the males of the partridge must be in considerable 
 excess in the south of England ; and I have been assured that this is 
 the case in Scotland. Mr. Weir on inquiring from the dealers who 
 receive at certain seasons large numbers of ruffs (Machetes pugnax), 
 was told that the males are much the more numerous. This same 
 naturalist has also inquired for me from the bird-catchers, who annu- 
 ally catch an astonishing number of various small species alive for 
 the London market, and he was unhesitatingly answered by an 
 old and trustworthy man, that with the chaffinch the males 
 are in large excess ; he thought as high as 2 males 
 to 1 female, or at least as high as 5 to 3. The males 
 
 * Brehm (" Illust Thlerleben," B. iv. s. 990) comes to the same conclusion. 
 
 t On the authority of L. Lloyd, " Game Birds of Sweden," 1867, pp. 12, 132. 
 
 J " Nat. Hist, of Selborne," letter xxix. edit, of 1825, vol. i,, p :39. 
 
 $ Mr. Jenner Weir received similar information, on making Inquiries 
 during the following year. To show the number of living chaffinches caught 
 I may mention that in 1869 there was a match between two experts, and one 
 man caught in a day 62, and another 40, male chafliuches. The greatest num- 
 ber ever caught by one man in a aingle*day was 70.
 
 PROPORTION OF THE SEXES. 281 
 
 of the blackbird, lie likewise maintained, were by far the more 
 numerous, whether caught by traps or by netting at night. These 
 statements may apparently be trusted, because this same man said 
 that the sexes are about equal with the lark, the twite (Linaria, 
 montana), and goldfinch. On the other hand, he is certain that with 
 the common linnet, the females preponderate greatly, but unequally, 
 during different years; during some years he has found the females 
 to the males as 4 to 1. It should, however, be borne in mind, 
 that the chief season for catching birds does not begin till September, 
 so that with some species partial migrations may have begun, and 
 the flocks at this period often consist of hens alone. Mr. Salvin 
 paid particular attention to the sexes of the humming-birds in Cen- 
 tral America, and lie is convinced that with most of the species the 
 males are in excess; thus one year he procured 204 specimens belong- 
 ing to ten species, and these consisted of 166 males and of only 38 
 females. With two other species the females were in excess; but 
 the proportions apparently vary either during different seasons or in 
 different localities; for on one occasion the males of Campylopterus 
 hemileucurus were to the females as 5 to 2, and on another occasion* 
 in exactly the reversed ratio. As bearing on this latter point, I may 
 add that Mr. Powys found in Corfu and Epirus the sexes of the 
 chaffinch keeping apart, and " the females by far the most numer- 
 ous;" while in Palestine, Mr. Tristram found " the male flocks 
 appearing greatly to exceed the female in number, "f So again 
 with the Quiscalus major, Mr. G. TaylorJ says, that in Florida there 
 were " very few females in proportion to the males," while in Hon- 
 duras the proportion was the other way, the species there having the 
 character of a polygamist. 
 
 Fish. With fish the proportional numbers of the sexes can be 
 ascertained only by catching them in the adult or nearly adult state; 
 and there are many difficulties in arriving at any just conclusion. 
 Infertile females might readily be mistaken for males, as Dr. Gtin- 
 ther has remarked to me in regard to trout. With some species the 
 males are believed to die soon after fertilizing the ova. With many 
 species the males are of much smaller size than the females, so that 
 a large number of males would escape from the same net by which 
 the females were caught. M. Carbonnier, || who has especially 
 attended to the natural history of the pike (Esox lucius), states that 
 many males, owing to their small size, are devoured by the larger 
 females; and he believes that the males of almost all fish are exposed 
 from this same cause to greater danger than the females. Neverthe- 
 less, in the few cases in which the proportional numbers have been 
 actually observed, the males appear to be largely in excess. Thus 
 Mr. R. Buist, the superintendent of the Stormontfield experiments, 
 
 *" Ibis," vol. ii, p. 260, as quoted in "Gould's Trochilidae," 1861, p. 52. 
 For the foregoing proportions, I am indebted to Mr. Salvin for a table of his 
 results. 
 
 t " Ibis," 1860, p, 137; and 1867, p. 369. 
 
 t " Ib"is," 1862. p, 187. 
 
 Leuckart quotes Bloch (Wagner, " Handworterbuch der Phys.," B. iv, 
 1853, s. T75), that with fish there are twice as many males as females. 
 
 Quoted in the " Farmer," March 18, 1869,- p. 369.
 
 282 THE DESCENT OF MAN. 
 
 says that in 1865, out of 70 salmon first landed for the purpose of 
 obtaining tlie ova, upward of 60 were males. In 1867 he again 
 " calls attention to the vast disproportion of the males to the females. 
 We had at the outset at least ten males to one female." Afterward 
 females sufficient for obtaining ova were procured. He adds, " from 
 the great proportion of the males, they are constantly fightiug and 
 tearing each other on the spawning-beds."* This disproportion, no 
 doubt, can be accounted for in part, but whether wholly is doubtful, 
 by the males ascending the rivers before the females. Mr. F. Buck- 
 land remarks in regard to trout, that "it is a curious fact that the 
 males preponderate very largely in number over the females. It 
 invariably happens that when the first rush of fish is made to the 
 net there will be at least seven or eight males to one female found 
 captive. I cannot quite account for this; either the males are more 
 numerous than the females, or the latter seek safety by concealment 
 rather than flight." lie then adds, that by carefully searching the 
 banks sufficient females for obtaining ova can be found, f Mr. H. 
 Lee informs me that out of 212 trout taken for this purpose in Lord 
 Portsmouth's park, 150 were males and 62 females. 
 
 The males of the Cyprinida? likewise seem to be in excess; but sev- 
 eral members of this family, viz., the carp, tench, bream and min- 
 now, appear regularly to follow the practice, rare in the animal king- 
 dom, of polyandry; for the female while spawning is always attended 
 by two males, one on each side, and in the case of the bream by three 
 or four males. This fact is so well known that it is always recom- 
 mended to stock a pond with two male tenches to one female, or at 
 least with three males to two females. With the minnow, an excel- 
 lent observer states, that on the spawning-beds the males are ten 
 times as numerous as the females; when a female comes among the 
 males, " she is immediately pressed closely by a male on each side; 
 and when they have been in that situation for a time are superseded 
 by two other males. " J 
 
 Insects. In this great class the Lepidoptera almost alone afford 
 means for judging of the proportional numbers of the sexes; for they 
 have been collected with special care by many good observers, and 
 have been largely bred from the egg or caterpillar state. I had hoped 
 that some breeders of silk-moths might have kept an exact record, 
 but after writing to France and Italy, and consulting various treatises, 
 I cannot find that this has ever been done. The general opinion ap- 
 pears to be that the sexes are nearly equal, but in Italy, as I hear 
 from Prof. Canestrini, many breeders are convinced that the females 
 are produced in excess. This same naturalist, however, informs :ne 
 that in the two yearly broods of the Ailanthus silk-moth (Borribyx 
 cynthia), the males greatly preponderate in the first, while in the 
 second the two sexes are nearly equal, or the females rather in 
 
 *"Tbe Stormontfield Piscieultural Experiments," 1866, p. 23. The 
 " Field " newspaper, June 20, 1867. 
 
 t " Land and Water," 1868, ; . 41. 
 
 iYarrell. "Hist. British Fishes," vol. i, 1826, p. 807; on the Cyprinus carpio, 
 P. 331; on the Tinea vulQdiis, p. 381; on tin; Abratnis brama, p. 33li. See, for the 
 minnow (Leueiscus phoxinug), " London's Mag. of Nat. Hist.," voL v, 1*32, p. 682.
 
 PROPORTION OF THE SEXES. 283 
 
 In regard to butterflies in a state of nature, several observers have 
 been much struck by the apparently enormous preponderance of the 
 males.* Thus Mr. Bates, f in speaking of several species, about a 
 hundred in number, which inhabit the Upper Amazons, says that 
 the males are much more numerous than the females, even in the 
 proportion of 100 to 1. In North America, Edwards, who 
 had great experience, estimates in the genus Papilio the males to the 
 females as 4 to 1; and Mr. Walsh, who informed me of this 
 statement, says that with P. turnus this is certainly the case. In 
 S. Africa, Mr. R. Trimen found the males in excess in nineteen spe- 
 cies; j: and in one of these, which swarms in open places, he estimated 
 the number of males as 50 to 1 female. With another species, 
 in which the males are numerous in certain localities, he collected 
 only five females during seven years. In the Island of Bourbon, M. 
 Maillard states that the males of one species of Papilio are twenty 
 times as numerous as the females. Mr. Trimen informs me that as 
 far as he has himself seen, or heard from others, it is rare for the 
 females of any butterfly to exceed the males in number; but three 
 South African species perhaps offer an exception. Mr. Wallace)! 
 states that the females of Ornithoptera cr&sus, in the Malay Archi- 
 pelago, are more common and more easily caught than the males; 
 but this is a rare butterfly. I may here add that in Hyperythra, a 
 genus of moths, Guenee says, that from four to five females are sent 
 in collections from India for one male. 
 
 When this subject of the proportional numbers of the sexes of 
 insects was brought before the Entomological Society, T it was 
 generally admitted that the males of most Lepidoptera, in the 
 adult or imago state, are caught in greater numbers than the females: 
 but this fact was attributed by various observers to the more 
 retiring habits of the females, and to the males emerging earlier 
 from the cocoon. This latter circumstance is well known to occur 
 with most Lepidoptera, as well as with other insects. So that, as M. 
 Personnat remarks, the males of the domesticated Bombyx Famafliai 
 are useless at the beginning of the season, and the females at the 
 end, from the want of mates.** I cannot, however, persuade myselt 
 that these causes suffice to explain the great excess of males in the 
 above cases of certain butterflies which are extremely common in 
 their native countries. Mr. Staiuton, who has paid very close atten- 
 tion during many years to the smaller moths, informs me that when 
 he collected them in the imago state, he thought that the males were 
 ten times as numerous as the females, but that since he has reared 
 them on a large scale from the caterpillar state he is convinced that 
 the females are the more numerous. Several entomologists concur 
 
 * Leuckart quotes Meinecke (Wagner, " Handworterbuch der Phys.," B. 
 iv, 1853, s. 775), that the males of butterflies are three or four times as numer- 
 ous as the females. 
 
 t " The Naturalist on the Amazons," vol. ii, 1863, pp, 238, 847. 
 
 $ " Pour of these cases are given by Mr. Trimen in his " Ehopalocera Africa 
 Australis."- 
 
 Quoted by Trimen, " Transact. Ent. Soc.," vol. v, part iv, 1866, p. 880. 
 
 I " Transact. Linn. 800.," vol. xxv, p. 37. 
 
 T ' Proo. Entomolog. Soc.," Feb. 17, 1868. 
 
 **Q,uoted by Dr. Wallace in " Proc. Ent. Soc.," 8d series, vol. v, 1867, p. 487.
 
 284 THE DESCENT OF MAN. 
 
 in this view. Mr. Doubleday, however, and some others, take an 
 opposite view, and are convinced that they have reared from the 
 eggs and caterpillars a larger proportion of males than of females. 
 
 Besides the more active habits of the males, their earlier emergence 
 from the cocoon, and in some cases their frequenting more open 
 stations, other causes may be assigned for an apparent or real differ- 
 ence in the proportional numbers of the sexes of Lepidoptera, when 
 captured in the imago state, and when reared from the egg or cater- 
 pillar state. I hear from Prof. Canestrini that it is believed by many 
 breeders in Italy that the female caterpillar of the silk-moth suffers 
 more from the recent disease than the male; and Dr. Staudinger 
 informs me that in rearing Lepidoptera more females die in the 
 cocoon than males. With many species the female caterpillar is 
 larger than the male, and a collector would naturally choose the 
 finest specimens, and thus unintentionally collect a larger number of 
 females. Three collectors have told me that this was their practice; 
 but Dr. Wallace is sure that most collectors take all the speci- 
 mens which they can find of the rarer kinds, which alone are worth 
 the trouble of rearing. Birds when surrounded by caterpillars 
 would probably devour the largest; and Prof. Canestrini informs me 
 that in Italy some breeders believe, though on insufficient evidence, 
 that in the first broods of the Ailanthus silk-moth the wasps destroy 
 a larger number of the female than of the male caterpillars. Dr. 
 Wallace further remarks that female caterpillars, from being larger 
 than the males, require more time for their development and con- 
 sume more food and moisture; and thus they would be exposed 
 during a longer time to danger from ichneumons, birds, etc. , and in 
 times of scarcity would perish in greater numbers. Hence it appears 
 quite possible that in a state of nature, fewer female Lepidoptera 
 may reach maturity than males; and for our special object we are 
 concerned with their relative numbers at maturity, when the sexea 
 are ready to propagate their kind. 
 
 The manner in which the males of certain moths congregate in 
 extraordinary numbers round a single female, apparently indicates a 
 great excess of males, though this fact may perhaps be accounted 
 for by the earlier emergence of the males from their cocoons. Mr. 
 Stainton informs me that from twelve to twenty males may often be 
 seen congregated round a female Elachista rufocinerea. It is well 
 known that if a virgin Lasiocampa quercus or Saturnia carpini be 
 exposed in a cage, vast numbers of males collect round her, and it 
 confined in a room will even come down the chimney to her. Mr. 
 Doubleday believes that he has seen from fifty to a hundred males of 
 both these species attracted in the course of a single day by a female 
 in confinement. In the Isle of Wight, Mr. Trimen exposed a box in 
 which a female of the Lasiocampa had been confined on the previous 
 day, and five males soon endeavored to gain admittance. In Aus- 
 tralia, M. Verreaux, having placed the female of a small Bombyx in 
 a box in his pocket, was followed by a crowd of males, so that about 
 300 entered the house with him. * 
 
 Mr. Doubleday has called my attention to M. Staudinger'sf list 
 
 * Blanchard, " Metamorphoses, Mceurs rtes Inaeotes," 186& pp. 83B-63<5. 
 + " Lepidopteren-Doubletten Liate," Berlin, No. x< I860.
 
 PROPORTION OF THE SEXES. 
 
 285 
 
 of Lepidoptera, which gives the prices of the males and females of 
 300 species or well-marked varieties of butterflies (Rhopalocera). 
 The prices for both sexes of the very common species are of course 
 the same; but in 114 of the rarer species they differ; the males 
 being in all cases, excepting one, the cheaper. On an average of the 
 prices of the 113 species, the price of the male to that of the 
 female is as 100 to 149; and this apparently indicates that inversely 
 the males exceed the females in the same proportion. About 
 2,000 species or varieties of moths (Heterocera) are catalogued, 
 those with wingless females being here excluded on account 
 of the difference in habits between the two sexes: of these 
 2,000 species, 141 differ in price according to sex, the males of 130 
 being cheaper, and those of only 11 being dearer than the females. 
 The average price of the males of the 130 species, to that of the 
 females, is as 100 to 143. With respect to the butterflies in this 
 price-list, Mr. Doubleday thinks (and no man in England has had 
 more experience), that there is nothing in the habits of the species 
 which can accoiint for the difference in the prices of the two sexes, 
 and that it can be accounted for only by an excess in the number 
 of the males. But I am bound to add that Dr. Staudinger informs 
 me that he is himself of a different opinion. He thinks that the 
 less active habits of the females and the earlier emergence of the 
 males will account for his collectors securing a larger number of 
 males than of females, and consequently for the lower prices of the 
 former. With respect to specimens reared from the caterpillar 
 state, Dr. Staudinger believes, as previously stated, that a greater 
 number of females than of males die while confined in the cocoons. 
 He adds that with certain species one sex seems to preponderate over 
 the other during certain years. 
 
 Of direct observations on the sexes of Lepidoptera, reared either 
 from eggs or caterpillars, I have received only the few following 
 
 
 Males. 
 
 Females . 
 
 The Eev. J. Hellins * of Exeter reared, during 1868, images 
 
 153 
 
 137 
 
 Mr. Albert Jones of Eltharn reared, during 1868, images of 
 9 species, which consisted of 
 During 1869 he reared imagos from 4 species, consisting 
 of 
 
 159 
 114 
 
 126 
 118 
 
 Mr. Buckler of Emsworth, Hants, during 1869, reared 
 imagos from 74 species, consisting of 
 Dr. Wallace of Colchester reared from one brood of Bom- 
 
 180 
 52 
 
 169 
 48 
 
 Dr. Wallace raised, from cocoons of Bombyx Pernyi sent 
 from China, during 1869 
 Dr. Wallace raised, during 1868 and 1869, from two lots of 
 
 224 
 52 
 
 123 
 46 
 
 Total 
 
 934 
 
 761 
 
 
 
 
 * This naturalist has been so kind as to send me some results from former 
 years, in which the females seemed to preponderate ; but so many of the 
 figures were estimates that I found it impossible to tabulate them.
 
 286 THE DESCENT OF MAN. 
 
 So that in these eight lots of cocoons and eggs males were pro- 
 duced in excess. Taken together the proportion of males is as 122.7 
 to 100 females. But the numbers are hardly large enough to be 
 trustworthy. 
 
 On the whole, from these various sources of evidence, all pointing 
 in the same direction, I infer that with most species of Lepidoptera 
 the mature males generally exceed the females in number, whatever 
 the proportions may be at their first emergence from the egg. 
 
 With reference to the other orders of insects, I have been able to 
 collect very little reliable information. With the stag-beetle (Lu- 
 canus cervus) " the males appear to be much more numerous than 
 the females:" but when, as Cornelius remarked during 1867, an 
 unusual number of these beetles appeared in one part of Germany, 
 the females appeared to exceed the males as 6 to 1. With one 
 of the Elateridae, the males are said to be much more numerous than 
 the females, and "two or three are often found united with one 
 female;* so that here polyandry seems to prevail." With Siagonium 
 (Staphylinidae), in which the males are furnished with horns, ' ' the 
 females are far more numerous than the opposite sex." Mr. Janson 
 stated at the Entomological Society that the females of the bark- 
 feeding Tomicus mllosus are so common as to be a plague, while the 
 males are so rare as to be hardly known. 
 
 It is hardly worth while saying anything about the proportion of 
 the sexes in certain species and even groups of insects, for the males 
 are unknown or very rare, and the females are parthenogenetic, 
 that is, fertile without sexual union ; examples of this are 
 afforded by several of the Cynipidae.f In all the gall-making 
 Cynipidse known to Mr. Walsh, the females are four or five times 
 as numerous as the males; and so it is, as he informs me, with the 
 gall-making Cecidomyiidse (Diptera). With some common species 
 of Saw-flies (Tenthrediuse) Mr. F. Smith has reared hundreds of 
 specimens from larvae of all sizes, but has never reared a single 
 male; on the other hand, Curtis says,^ that with certain species 
 (Athalia) bred by him, the males were to the females as 6 to 1 ; 
 while exactly the reverse occurred with the mature insects of the 
 same species caught in the fields. In the family of bees, Hermann 
 Muller collected a large number of specimens of many species, and 
 reared others from the cocoons, and counted the sexes. He found 
 that the males of some species greatly exceeded the females in num- 
 ber; in others the reverse occurred; and in others the two sexes were 
 nearly equal. But as in most cases the males emerge from the co- 
 coons before the females, they are at the commencement of the breed- 
 ing season practically in excess. Miiller also observed that the rela- 
 tive number of the two sexes in some species differed much in differ- 
 ent localities. But as H. Mtiller has himself remarked to me, these 
 remarks must be received with some caution, as one sex might more 
 
 * Gunther's " Record of Zoological Literature," 1867, p. 260. On the excess 
 of female Lueanus, ibid. p. 250. On the males of Lucanus in England, West- 
 wood, "Modern Class of Insects," vol i. p. 187. On the Siagonium, ibid. p. 172. 
 
 t Walsh in "The American Entomologist," voL i, 1869, p. 103. F. Smith. 
 " Record of Zoological Literature," 1867, p. 328. 
 
 J " Farm Insects." pp. 45-16. 
 
 " Anwendung der Darwinschen Lehre Verb. d. u. V. Jahrg.," xxlv.
 
 PROPORTION OF THE SEXES. 287 
 
 easily escape observation than the other. Thus his brother Fritz 
 Miiller has noticed in Brazil that the two sexes of the same species of 
 bee sometimes frequent different kinds of flowers. With respect to 
 the Orthoptera, I know hardly anything about the relative number of 
 the sexes; Korte,* however, says" that out of 500 locusts which he 
 examined, the males were to" the females as 5 to 6, With the 
 Neuroptera, Mr. Walsh states that in many, but by no means in all 
 the species of the Odonatous group, there is a great overplus of males; 
 in the genus Hetserina, also, the males are generally at least four 
 times as numerous as the females. In certain species in the genus 
 Gornphus the males are equally in excess, while in two other species 
 the females are twice or thrice as numerous as the males. In some 
 European species of Psocus thousands of females may be collected 
 without a single male, while with other species of the same genus 
 both sexes are common, f In England, Mr. MacLachlan has captured 
 hundreds of the female Apatania muliebris, but has never seen the 
 male; and of Boreus hy emails only four or five males have been seen 
 here. \ With most of these species (excepting the Tenthredinae) there 
 is at present no evidence that the females are subject to partheno- 
 genesis; and thus we see how ignorant we are of the causes of the 
 apparent discrepancy in the proportion of the two sexes. 
 
 In the other classes of the Articulata I have been able to collect 
 still less information. With spiders, Mr. Blackwall, who has care- 
 fully attended to this class during many years, writes to me that the 
 males from their more erratic habits are more commonly seen, and 
 therefore appear more numerous. This is actually the case with a 
 few species; but he mentions several species in six genera, in which 
 the females appear to be much more numerous than the males. The 
 small size of the males in comparison with the females (a peculiarity 
 which is sometimes carried to an extreme degree), and their widely 
 different appearance, may account in some instances for their rarity 
 in collections. || 
 
 Some of the lower Crustaceans are able to propagate their kind 
 sexually, and this will account for the extreme rarity of the males; 
 thus Von Siebold^f carefully examined no less than 13,000 specimens 
 of Apus from twenty-one localities, and among these he found only 
 319 males. With some other forms (as Tanais and Cypris), as Fritz 
 Miiller informs me, there is reason to believe that the males are much 
 shorter-lived than the females; and this would explain their scarcity, 
 supposing the two sexes to be at first equal in number. On the other 
 hand, Miiller has invariably taken far more males than females of 
 the Diastylidae and of Cypridina on the shores of Brazil; thus with a 
 
 * " Die Strich, Zug oder Wanderheuschrecke," 1828, p. 20. 
 
 t " Observations on North American Neuroptera," by H. Hagen and B. D. 
 Walsh, "Proc. Ent. Soc., Philadelphia," Oct., 1863, pp. 168, 223, 239. 
 
 $ " Proc. Ent. Soc., London," Feb. 17, 1868. 
 
 Another great authority with respect to this class. Prof. Thorell, of Upsala 
 (" On European Spiders," 1863-1870, part i, p. 205), speaks as if female spiders 
 were generally commoner than the males. 
 
 II See, on this subject, Mr. O. P. Cambridge, as quoted in " Quarterly Jour- 
 nal of Science," 1868, p. 429. 
 
 V'Beitrage zur Parthenogenesis," p. 174.
 
 288 THE DESCENT OF MAN. 
 
 species in the latter genus, 63 specimens caught the same day included 
 57 males; but he suggests that this preponderance may be due to 
 some unknown difference in the habits of the two sexes. With one 
 of the higher Brazilian crabs, namely, a Gelasimus, Fritz Miiller 
 found the males to be more numerous than the females. According 
 to the large experience of Mr. C. Spence Bate, the reverse seems to 
 be the case with six common British crabs, the names of which he 
 has given me. 
 
 The Proportion of the Sexes in Relation to Natural 
 Selection. There is reason to suspect that in some cases 
 man has by selection indirectly influenced his own sex- 
 producing powers. Certain women tend to produce during 
 their whole lives more children of one sex than of the 
 other; and the same holds good of many animals, for 
 instance, cows and horses; thus Mr. Wright, of Yeldersley 
 House, informs me that one of his Arab mares, though put 
 seven times to different horses, produced seven fillies. 
 Though I have very little evidence on this head, analogy 
 would lead to the belief that the tendency to produce 
 either sex would be inherited like almost every other 
 peculiarity, for instance, that of producing twins; and con~ 
 cerning the above tendency a good authority, Mr. J. 
 Downing, has communicated to me facts which seem to 
 prove that this does occur in certain families of short-horn 
 cattle. Col. Marshall* has recently found on careful 
 examination that the Todas, a hill tribe of India, consist 
 of 112 males and 84 females of all ages that is in a ratio 
 of 133.3 males to 100 females. The Todas, who are poly- 
 audrous in their marriages, during former times invariably 
 practiced female infanticide; but this practice has now 
 been discontinued for a considerable period. Of the chil- 
 dren born within late years the males are more numerous 
 than the females in the proportion of 124 to 100. Col. 
 Marshall accounts for this fact in the following ingenious 
 manner: " Let us for the purpose of illustration take three 
 families as representing an average of the entire tribe; say 
 that one mother gives birth to six daughters and no sons; 
 a second mother has six sons only, while the third mother 
 has three sons and three daughters. The first mother, fol- 
 lowing the tribal custom, destroys four daughters and pre- 
 serves two. The second retains her six sons. The third 
 kills two daughters and keeps one, as also her three sons. 
 
 *"The Todas," 1873, pp. 100, 111, 194, 196.
 
 PROPORTION OF THE SEXES. 289 
 
 We have then from the three families nine sons and three 
 daughters with which to continue the breed. But while 
 the males belong to families in which the tendency to pro- 
 duce sons is great the females are of those of a converse 
 inclination. Thus the bias strengthens with each genera- 
 tion until, as we find, families grow to have habitually 
 more sons than daughters." 
 
 That this result would follow from the above form of 
 infanticide seems almost certain; that is if we assume that 
 a sex-producing tendency is inherited. But as the above 
 numbers are so extremely scanty I have searched for addi- 
 tional evidence, but cannot decide whether what I have 
 found is trustworthy; nevertheless the facts are, perhaps, 
 worth giving. The Maories of New Zealand have long 
 practiced infanticide ; and Mr. Fenton* states that he 
 " has met with instances of women who have destroyed 
 four, six and even seven children, mostly females. How- 
 ever, the universal testimony of those best qualified to 
 judge is conclusive that this custom has for many years 
 been almost extinct. Probably the year 1835 may be 
 named as the period of its ceasing to exist/' Now 
 among the New Zealanders, as with the Todas, male births 
 are considerably in excess. Mr. Fenton remarks (p. 30) : 
 " One fact is certain, although the exact period of the 
 commencement of this singular condition of the dispropor- 
 tion of the sexes cannot be demonstratively fixed, it is quite 
 clear that this course of decrease was in full operation 
 during the years 1830 to 1844, when the non-adult pop-j 
 ulation of 1844 was being produced, and has continued 
 with great energy up to the present time." The following 
 statements are taken from Mr. Fenton (p. 26), but as the 
 numbers are not large, and as the census was not accu- 
 rate, uniform results cannot be expected. It should be 
 borne in mind in this and the following cases, that the 
 normal state of every population is an excess of women, at 
 least in all civilized countries, chiefly owing to the greater 
 mortality of the male sex during yoiith, and partly to acci- 
 dents of all kinds later in life. In 1858, the native popula- 
 tion of New Zealand was estimated as consisting of 31,667 
 males and 24, 303 females of all ages, that is, in the ratio 
 
 *" Aboriginal Inhabitants of New Zealand: Government Report." 
 1859, p. 36.
 
 290 THE DESCENT OF MAN. 
 
 of 130.3 males to 100 females. But during this same year 
 and in certain limited districts, the numbers were ascer- 
 tained with much care, and the males of all ages were here 
 753 and the females GIG; that is in the ratio of 122.2 males 
 to 100 females. It is more important for us that during 
 this same year of 1858, the non-adult males within the 
 same district were found to be 178, and the non-adult 
 females 142, that is in the ratio of 125.3 to 100. It may 
 be added that in 1844, at which period female infanticide 
 had only lately ceased, the non-adult males in one district 
 were 281, and the non-adult females only 194, that is in the 
 ratio of 144.8 males to 100 females. 
 
 In the Sandwich Islands, the males exceed the females 
 in number. Infanticide was formerly practiced there to a 
 frightful extent, but was by no means confined to female 
 infants, as is shown by Mr. Ellis, * and as I have been informed 
 by Bishop Staley and the Eev. Mr. Coau. Nevertheless, 
 another apparently trustworthy writer, Mr. Jarves,f whoso 
 observations apply to the whole archipelago, remarks: 
 " Numbers of women are to be found who confess to the 
 murder of from three to six or eight children," and he adds, 
 " females from being considered less useful than males 
 were more often destroyed." From what is known to 
 occur in other parts of the world this statement is 
 probable; but must be received with much caution. The 
 practice of infanticide ceased about the year 1819, when 
 idolatry was abolished and missionaries settled in the 
 islands. A careful census in 1839 of the adult and taxable 
 men and women in the island of Kauai and in one district 
 of Oahu (Jarves, p. 404), gives 4,723 males and 3,77G 
 females; that is in the ratio of 125.08 to 100. At the same 
 time the number of males under fourteen years in Kauai 
 and under eighteen in Oahu was 1,797, and of females of 
 the same ages 1,429; and here we have the ratio of 125.75 
 males to 100 females. 
 
 In a census of all the islands in 1850,J the males of all 
 ages amount to 36,272, and the females to 33,128, or as 
 109.49 to 100. The males under seventeen years amounted 
 
 * " Narrative of a Tour through Hawaii," 1826, p. 298. 
 f "History of the Sandwich Islands," 1843, p. 93. 
 J This is given in the Kev. H. T. Cheever'a " Life in the Sandwich 
 Islands," 1851, p. 277.
 
 PROPORTION OF THE SEXES. 291 
 
 to 10,773, and the females under the same age to 9,593, or 
 as 112.3 to 100. From the census of 1872 the proportion 
 of males of all ages (including half-castes) to females is as 
 125.36 to 100. It must be borne in mind that all these 
 returns for the Sandwich Islands give the proportion of 
 living males to living females, and not of the births; and 
 judging from all civilized countries the proportion of males 
 would have been considerably higher if the numbers had 
 referred to births.* 
 
 From the several foregoing cases we have some reason to 
 believe that infanticide practiced in the manner above 
 explained, tends to make a male-producing race; but I am 
 far from supposing that this practice in the case of man, or 
 some analogous process with other species, has been the sole 
 determining cause of an excess of males. There may be 
 some unknown law leading to this result in decreasing 
 
 *Dr. Coulter, in describing (" Journal R. Geograph. Soc.," vol. v, 
 1835, p. 67) the state of California about the year 1830, says that the 
 natives, reclaimed by the Spanish missionaries, have nearly all per- 
 ished, or are perishing, although well treated, not driven from their 
 native land, and kept from the use of spirits. He attributes this, in 
 great part, to the undoubted fact that the men greatly exceed the 
 women in number; but he does not know Avhether this is due to a 
 failure of female offspring, or to more females dying during early 
 youth. The latter alternative, according to all analogy, is very 
 improbable. He adds that ' ' infanticide, properly so called , is not 
 common, though very frequent resource is had to abortion." If Dr. 
 Coulter is correct about infanticide, this case cannot be advanced in 
 support of Col. Marshall's view. From the rapid decrease of the 
 reclaimed natives, we may suspect that, as in the cases lately given, 
 their fertility has been diminished from changed habits of life. I 
 had hoped to gain some light on this subject from the breeding of 
 dogs; inasmuch as in most breeds, with the exception, perhaps, of 
 greyhounds, many more female puppies are destroyed than males, 
 just as with the Toda infants. Mr. Cupples assures me that this is 
 usual with Scotch deer-hounds. Unfortunately I know nothing of 
 the proportion of the sexes in any breed, excepting greyhounds, and 
 there the male births are to the females as 110.1 to 100. Now from 
 inquiries made from many breeders, it seems that the females are in 
 some respects more esteemed, though otherwise troublesome; and it 
 does not appear that the female puppies of the best-bred dogs are 
 systematically destroyed more than the males, though this does some- 
 times take place to a limited extent. Therefore I am unable to 
 decide whether we can, on the above principles, account for the pre- 
 ponderance of male births in greyhounds. On the other hand, we 
 have seen that with horses, cattle and sheep, which are too valuable 
 for the young of either sex to be destroyed, if there is any difference, 
 the females are slightly in excess.
 
 292 THE DESCENT OF M*1T. 
 
 races which have already become somewhat infertile. 
 Besides the several causes previously alluded to, the greater 
 facility of parturition among savages, and the less conse- 
 quent injury to their male infants, would tend to increase 
 the proportion of live-born males to females. There does 
 not, however, seem to be any necessary connection between 
 savage life and a marked excess of males; that is if we may 
 judge by the character of the scanty offspring of the lately 
 existing Tasmanians and of the crossed offspring of the 
 Tahitiaus now inhabiting Norfolk Island. 
 
 As the males and females of many animals differ some- 
 what in habits, and are exposed in different degrees to 
 danger, it is probable that in many cases more of one sex 
 than of the other are habitually destroyed. But as far as I 
 can trace out the complication of causes an indiscriminate 
 though large destruction of either sex would not tend to 
 modify the sex-producing power of the species. With 
 strictly social animals, such as bees or ants, which produce 
 a vast number of sterile and fertile females in comparison 
 with the males, and to whom this preponderance is of para- 
 mount importance, we can see that those communities 
 would flourish best which contained females having a 
 strong inherited tendency to produce more and more 
 females; and in such cases an unequal sex-producing ten- 
 dency would be ultimately gained through natural selection. 
 With animals living in herds or troops in which the males 
 come to the front and defend the herd, as with the bisons 
 of North America and certain baboons, it is conceivable 
 that a male-producing tendency might be gained by natural 
 selection; for the individuals of the better defended herds 
 would leave more numerous descendants. In the case of 
 mankind the advantage arising from having a preponderance 
 of men in the tribe is supposed to be one chief cause of 
 the practice of female infanticide. 
 
 In no case, as far as we can see, would an inherited ten- 
 dency to produce both sexes in equal numbers or to produce 
 one sex in excess, be a direct advantage or disadvantage to 
 certain individuals more than to others; for instance, an 
 individual with a tendency to produce more males than 
 females would not succeed better in the battle for life than 
 an individual with an opposite tendency; and therefore a 
 tendency of this kind could not be gained through natural 
 election. Nevertheless, there are certain animals (for
 
 PROPORTION OF THE SEXES. 293 
 
 instance, fishes and cirripedes) in which two or more males 
 appear to be necessary for the fertilization of the female; 
 and the males accordingly largely preponderate, but it is 
 by no means obvious how this male-producing tendency 
 could have been acquired. I formerly thought that when 
 a tendency to produce the two sexes in equal numbers was 
 advantageous to the species it would follow from natural 
 selection, but I now see that the whole problem is so intri- 
 cate that it is safer to leave its solution for the future.
 
 294 THE DESCENT OF MAN. 
 
 CHAPTER IX. 
 
 SECONDARY SEXUAL CHARACTERS IN THE LOWER CLASSES 
 OF THE ANIMAL KINGDOM. 
 
 These characters absent in the lowest classes Brilliant colors 
 Mollusca Annelids Crustacea, secondary sexual characters 
 strongly developed; dimorphism; color; characters not acquired 
 before maturity Spiders, sexual colors of; stridulation by the 
 males Myriapoda. 
 
 WITH animals belonging to the lower classes, the two 
 sexes are not rarely united in the same individual, and there- 
 fore secondary sexual characters cannot be developed. In 
 many cases where the sexes are separate both are perma- 
 nently attached to some support, and the one cannot search 
 or struggle for the other. Moreover it is almost certain 
 that these animals have too imperfect senses and much too 
 low mental powers to appreciate each other's beauty or 
 other attractions, or to feel rivalry. 
 
 Hence in these classes or sub-kingdoms, such as the Pro- 
 tozoa, Coelenterata, Echinodermata, Scolecida secondary 
 sexual characters of the kind which we have to consider do 
 not occur; and this fact agrees with the belief that such 
 characters in the higher classes have been acquired through 
 sexual selection, which depends on the will, desire and 
 choice of either sex. Nevertheless some few apparent 
 exceptions occur; thus, as I hear from Dr. Baird, the males 
 of certain Entozoa or internal parasitic worms differ slightly 
 in color from the females; but we have no reason to sup- 
 pose that such differences have been augmented through 
 sexual selection. Contrivances by which the male holds 
 the female, and which are indispensable for the propaga- 
 tion of the species, are independent of sexual selection, and 
 have been acquired through ordinary selection. 
 
 Many of the lower animals, whether hermaphrodites or 
 with separate sexes, are ornamented with the most brilliant 
 tints, or are shaded and striped in an elegant manner; for 
 instance, many corals and sea-anemones (Actinias), some
 
 SEXUAL SELECTION. 295 
 
 jelly-fish (Medusae, Porpita, etc.), some Planarise, many 
 star-fishes, Echini, Ascidians, etc.; but we may conclude 
 from the reasons already indicated, namely, the union of 
 the two sexes in some of these animals, the permanently 
 affixed condition of others, and the low mental powers of 
 all that such colors do not serve as a sexual attraction and 
 have not been acquired through sexual selection. It 
 should be borne in mind that in no case have we sufficient 
 evidence that colors have been thus acquired, except where 
 one sex is much more brilliantly or conspicuously colored 
 than the other, and where there is no difference in habits 
 between the sexes sufficient to account for their different 
 colors. But the evidence is rendered as complete as it can 
 ever be only when the more ornamented individuals, almost 
 always the males, voluntarily display their attractions 
 before the other sex; for we cannot believe that such dis- 
 play is useless, and if it be advantageous sexual selection 
 will almost inevitably follow. AVe may, however, extend 
 this conculsion to both sexes when colored alike if their 
 colors are plainly analogous to those of one sex alone in 
 certain other species of the same group. 
 
 How, then, are we to account for the beautiful or even 
 gorgeous colors of many animals in the lowest classes? It 
 appears doubtful Avhether such colors often serve as a pro- 
 tection; but that we may easily err on this head will ba 
 admitted by every one who reads Mr. Wallace's excellent 
 essay on this subject. It would not, for instance, at first 
 occur to any one that the transparency of the Medusae, or 
 jelly-fish, is of the highest service to them as a protection; 
 but when we are reminded by Hackel that not only the 
 Medusas but many floating mollusca, crustaceans and even 
 small oceanic fishes partake of this same glass-like appear- 
 ance, often accompanied by prismatic colors, we can hardly 
 doubt that they thus escape the notice of pelagic birds and 
 other enemies. M. G-iard is also convinced* that the 
 bright tints of certain sponges and ascidians serve as a pro- 
 tection. Conspicuous colors are likewise beneficial to many 
 animals as a warning to their would-be devourers that they 
 are distasteful, or that they possess some special means of 
 defense; but this subject will be discussed more conven- 
 iently hereafter. 
 
 We can in our ignorance of most of the lowest animals 
 
 * " Archives de Zoolog. Exper. " Oct., 1872, p, 568.
 
 296 THE DESCENT OF MAN. 
 
 only say that their bright tints result either from the 
 chemical nature or the minute structure of their tissues 
 independently of any benefit thus derived. Hardly any 
 color is finer than that of arterial blood; but there is no 
 reason to suppose that the color of the blood is in itself 
 any advantage; and though it adds to the beauty of the 
 maiden's cheek, no one will pretend that it has been 
 acquired for this purpose. So again with many animals, 
 especially the lower ones, the bile is richly colored; thus, as 
 I am informed by Mr. Hancock, the extreme beauty of the 
 Eolidae (naked sea-slugs) is chiefly due to the biliary glands 
 being seen through the translucent integuments this 
 beauty being probably of no service to these animals. The 
 tints of the decaying leaves in an American forest are 
 described by every one as gorgeous; yet no one supposes 
 that these tints are of the least advantage to the trees. 
 Bearing in mind how many substances closely analogous to 
 natural organic compounds have been recently formed by 
 chemists, and which exhibit the most splendid colors, it 
 would have been a strange fact if substances similarly 
 colored had not often originated, independently of any 
 useful end thus gained, in the complex laboratory of living 
 organisms. 
 
 The Sul-Kingdom of the Molluska. Throughout this 
 great division of the animal kingdom, as far as I can dis- 
 cover, secondary sexual characters, such as we are here con- 
 sidering, never occur. Nor could they be expected in the 
 three lowest classes, namely, in the Ascidians, Polyzoa and 
 Brachiopods (constituting the Molluscoida of some authors), 
 for most of these animals are permanently affixed to a sup- 
 port or have their sexes united in the same individual. In 
 the Lamellibranchiata, or bivalve shells, hermaphroditism 
 is not rare. In the next higher class of the Gasteropoda, 
 or univalve shells, the sexes are either united or separate. 
 But in the latter case the males never possess special organs 
 for finding, securing, or charming the females, or for fight- 
 ing with other males. As I am informed by Mr. Gwyn 
 Jeffreys, the sole external difference between the sexes con- 
 sists in the shell sometimes differing a little in form; for 
 instance, the shell of the male periwinkle (Littorina 
 liUored) is narrower and has a more elongated spire than 
 that of the female. But differences of this nature, it may
 
 MOLLUSKS. 297 
 
 be presumed, are directly connected with the act of repro- 
 duction, or with the development of the ova. 
 
 The Gasteropoda, though capable of locomotion and 
 furnished with imperfect eyes, do not appear to be endowed 
 with sufficient mental powers for the members of the same 
 sex to struggle together in rivalry, and thus to acquire 
 secondary sexual characters. Nevertheless with the pul- 
 moniferous gasteropods, or land-snails, the pairing is pre- 
 ceded by courtship; for these animals, though hermaphro- 
 dites, are compelled by their structure to pair together. 
 Agassiz remarks:* "Quiconque a eu Foccasion d'observer 
 les amours des limaqons, ne saurait mettre en doute la 
 seduction deployee dans les mouvements et les allures qui 
 preparent et accomplissent le double embrassement de ces 
 hermaphrodites." These animals appear also susceptible of 
 some degree of permanent attachment ; an accurate 
 observer, Mr. Lonsdale, informs me that he placed a pair 
 of land-snails (Helix pomatid), one of which was weakly, 
 into a small and ill-provided garden. After a short time 
 the strong and healthy individual disappeared, and was 
 traced by its track of slime over a wall into an adjoining 
 well-stocked garden. Mr. Lonsdale concluded that it had 
 deserted its sickly mate; but, after an absence of twenty- 
 four hours, it returned, and apparently communicated the 
 result of its successful exploration, for both then started 
 along the same track and disappeared over the wall. 
 
 Even in the highest class of the Molluska, the Cephalo- 
 poda or cuttle-fishes, in which the sexes are separate, 
 secondary sexual characters of the present kind do not, as 
 far as I can discover, occur. This is a surprising circum- 
 stance, as these animals possess highly-developed sense- 
 organs and have considerable mental powers, as will be 
 admitted by every one who has watched their artful endeav- 
 ors to escape from an enemy, f Certain Cephalopoda, how- 
 ever, are characterized by one extraordinary sexual charac- 
 ter, namely that the male element collects within one of 
 the arms or tentacles, which is then cast off, and clinging 
 by its sucking-disks to the female, lives for a time an inde- 
 pendent life. So completely does the cast-off arm resemble 
 a separate animal, that it was described by Cuvier as a para- 
 
 * " De 1'Espece et de la Class," etc., 1869, p. 106. 
 f- See, for instance, the account which I have given in iny " Jour 
 nal of Researches," 1845, p. 7.
 
 298 THE DESCENT OF MAN. 
 
 sitic worm under the name of Hectocotyle. But this mar 
 velous structure may be classed as a primary rather than as 
 a secondary sexual character. 
 
 Although with the Molluska sexual selection does not 
 seem to have come into play ; yet many univalve and 
 bivalve shells, such as volutes, cones, scallops, etc., are 
 beautifully colored and shaped. The colors do not appear 
 in most cases to be of any use as a protection; they are 
 probably the direct result, as in the lowest classes, of the 
 nature of the tissues; the patterns and the sculpture of the 
 shell depending on its manner of growth. The amount of 
 light seems to be influential to a certain extent; for 
 although, as repeatedly stated by Mr. Gwyn Jeffreys, the 
 shells of some species living at a profound depth are brightly 
 colored, yet we generally see the lower surfaces, as well as 
 the parts covered by the mantle, less highly colored than 
 the upper and exposed surfaces.* In some cases, as with 
 shells living among corals or brightly tinted sea-weeds, the 
 bright colors may serve as a protection, f But that many 
 of the nudi-branch molluska, or sea-slugs, are as beauti- 
 fully colored as any shells, may be seen in Messrs. Alder 
 and Hancock's magnificent work; and from information 
 kindly given me by Mr. Hancock, it seems extremely 
 doubtful whether these colors usually serve as a protection. 
 With some species this may be the case, as with one kind 
 which lives on the green leaves of algae, and is itself bright- 
 green. But many brightty-colored, white, or otherwise 
 conspicuous species, do not seek concealment; while again 
 some equally conspicuous species, as well as other dull- 
 colored kinds, live under stones and in dark recesses. So 
 that with these nudibranch mollusks, color apparently does 
 'not stand in any close relation to the nature of the places 
 which they inhabit. 
 
 These naked sea-slugs are hermaphrodites, yet they pair 
 together, as do land-snails, many of which have extremely 
 pretty shells. It is conceivable that two hermaphrodites, 
 
 *I have given ("Geolog. Observations on Volcanic Islands," 1844, 
 p. 53) a curious instance of the influence of light on the colors of a 
 iromlescent incrustation, deposited by the surf on the coast-rocks of 
 Ascension, and formed by the solution of triturated sea-shells. 
 
 f Dr. Morse has lately discussed this subject in his paper on the 
 Adaptive Coloration of Molluska, " Proc. Boston Soc. of Nat. Uist..'' 
 vol. xiv, April, 1871.
 
 CRUSTACEANS. 299 
 
 attracted by each other's greater beauty, might unite 
 and leave offspring which would inherit their parents' 
 greater beauty. But with such lowly-organized creatures 
 this is extremely improbable. Nor is it at all obvious how 
 the offspring from the more beautiful pairs of hermaphro- 
 dites would have any advantage over the offspring of the 
 less beautiful, so as to increase in number, unless indeed 
 |vigor and beauty generally coincided. We have not here 
 the case of a number of males becoming mature before 
 the females, with the more beautiful males selected by the 
 more vigorous females. If, indeed, brilliant colors were 
 beneficial to a hermaphrodite animal in relation to its gen- 
 eral habits of life, the more brightly-tinted individuals would 
 succeed best and would increase in number; but this would 
 be a case of natural and not of sexual selection. 
 
 8nb - kingdom of the Vermes Annelida (or Sea- 
 worms). In this class, although the sexes, when separate, 
 sometimes differ from each other in characters of such im- 
 portance that they have been placed under distinct genera 
 or even families, yet the differences do not seem of the kind 
 which can be safely attributed to sexual selection. These 
 animals are often beautifully colored, but as the sexes do 
 not differ in this respect we are but little concerned with 
 them. Even the Nemertians, though so lowly organized., 
 " vie in beauty and variety of coloring with any other 
 group in the vertebrate series;" yet Dr. Mclntosb * cannot 
 discover that these colors are of any service. The sedentary 
 annelids become duller-colored, according to M. Quatre- 
 fages,f after the period of reproduction; and this I pre- 
 sume may be attributed to their less vigorous condition at 
 that time. All these worm-like animals apparently stand 
 too low in the scale for the individuals of either sex to exert 
 any choice in selecting a partner, or for the individuals of 
 the same sex to struggle together in rivalry. 
 
 Sub -kingdom of the Arthropoda Crustacea. In 
 this great class we first meet with undoubted secondary 
 sexual characters, often" developed in a remarkable manner. 
 
 *See his beautiful monograph on " British Annelids," part i, 1873, 
 p. 3. 
 
 t See M. Perrier, " 1'Origine de 1'Homme d'apres Darwin," " Revue 
 Scientifique," Feb., 1873 D- 866.,
 
 300 THE DESCENT OF MAN. 
 
 Unfortunately the habits of crustaceans are very imper- 
 fectly known, and we cannot explain the uses of many 
 structures peculiar to one sex. With the lower parasitic 
 species the males are of small size, and they alone are fur- 
 nished with perfect swimming legs, ateunae and sense- 
 organs; the females being destitute of these organs, with 
 their bodies often consisting of a mere distorted mass. But 
 these extraordinary differences between the two sexes are no 
 doubt related to their widely different habits of life, and 
 consequently do not concern us. In various crustaceans, 
 belonging to distinct families, the anterior attennae are fur- 
 nished with peculiar thread-like bodies, which are believed 
 to act as smelling-organs, and these are much more numerous 
 in the males than in the females. As the males, without any 
 unusual development of their olfactory organs, would almost 
 certainly be able sooner or later to find the females, the 
 increased number of the smelling- threads has probably been 
 acquired through sexual selection, by the better provided 
 males having been tKe more successful in finding partners 
 and in producing offspring. Fritz Miiller has described a 
 remarkable dimorphic species of Tanais in which the male 
 is represented by two distinct forms which never graduate 
 into each other. In the one form the male is furnished 
 with more numerous smelling-threads, and in the other 
 form with more powerful and more elongated chelae or 
 pincers which serve to hold the female. Fritz Muller sug- 
 gests that these differences between the two male forms of 
 the same species may have originated in certain individuals 
 having varied in the number of the smelling-threads, while 
 other individuals varied in the shape and size of their 
 chelae; so that of the former those which were best able to 
 find the female, and of the latter those which were best 
 able to hold her, have left the greatest number of progeny 
 to inherit their respective advantages.* 
 
 In some of the lower crustaceans the right anterior 
 antenna of the male differs greatly in structure from the 
 left, the latter resembling in its simple tapering joints the 
 antennae of the female. In the male the modified antenna 
 is either swollen in the middle or angularly bent or con- 
 
 *" Facts and Arguments for Darwin," English translat., 1869, p. 
 20. See the previous discussion on the olfactory threads. Sars haa 
 described a somewhat analogous case (as quoted in " Nature," 1870, 
 p. 455) in a Norwegian crustacean, the Poutoporeia affinis.
 
 CRUSTACEANS. 
 
 301 
 
 verted (fig. 4) into an elegant and sometimes wonderfully 
 complex prehensile organ.* It serves, as I hear from Sir 
 J. Lubbock, to hold the female, for this same purpose one 
 of the two posterior legs (#) on the same side of the body 
 is converted into a forceps. In another family the inferior 
 or posterior antennae are "curiously zigzagged " in the 
 males alone. 
 
 In the higher crustaceans the a 
 
 anterior legs are developed into 
 chelae or pincers; and these are gen- 
 erally larger in the male than in the 
 female so much so that the market 
 value of the male edible crab ( Cancer 
 pagurus), according to Mr. C. Spence 
 Bate, is five times as great as that of 
 the female. In many species the 
 chelae are of unequal size on the 
 opposite side of the body, the right- 
 hand one being, as I am informed by 
 Mr. Bate, generally though not 
 invariably the largest. This ine- 
 quality is also often much greater in 
 the male than in the female. The 
 two chelae of the male often differ 
 in structure (figs. 5, 6 and 7), the 
 smaller one resembling that of the 
 female. What advantage is gained 
 by their inequality in size on the 
 opposite sides of the body and by the 
 inequality being much greater in the Fir 4 
 the male than in the female; and 
 why when they are of equal size both 
 are often much larger in the male a ' 
 than in the female is not known. As . 
 I hear from Mr. Bate, the chelae are b ' 
 sometimes of such length and size c - Ditto of female. 
 that they cannot possibly be used for 
 carrying food to the mouth. In the males of certain fresh- 
 
 * See Sir J. Lubbock in " Annals and Mag. of Nat. Hist.," vol. xi, 
 1853, pi. i and x; and vol. xii, 1853, pi. vii. See also Lubbock in 
 "Transact. Ent. Soc.," vol iv, new series, 1853-1858, p. 8. With 
 respect to the zigzagged antennae mentioned below, see Fritz Miiller, 
 " Facts and Arguments for Darwin," 1809, p. 40. foot note. 
 
 Labidocera Darwini} 
 (from Lubbock). 
 
 prehensile organ 
 
 rof thoraci
 
 302 
 
 THE DESCENT OF MAN. 
 
 water prawns (Palaemon) the right leg is actually longer than 
 the whole body.* The great size of the one leg with its 
 chelse may aid the male in fighting with his rivals; but this 
 
 Fig. 5. Anterior part of body of Oallianassa Cfrom Milne-Edwards), 
 showing the unequal and differentl; -constructed rig'v and 
 left hand chelae of the male. 
 
 K B. The artist by mistake has reversed the drawing, and made the 
 left-hand chela the largest. 
 
 Fig. 6. 
 
 Fig. 7. 
 
 Fig. 6. Second leg of male Orchestia Tucuratinga (from Fritz Muller). 
 Fig. 7. Ditto of female. 
 
 will not account for their inequality in the female on the 
 opposite sides of the body. In Gelasimus, according to a 
 
 *See a paper by Mr. C. Spence Bate, with figures in " Proc. 
 Zoolog. Soc.," 1868, p. 363; and on the nomenclature of the genus, 
 ibid, p. 585. I am greatly indebted to Mr. Spence Bate for nearly all 
 the above statements with respect to the chelae of the higher 
 
 crustaceans,
 
 CRUSTACEANS. 303 
 
 statement quoted by Milne-Edwards, * the male and the 
 female live in the same burrow, and this shows that they 
 pair; the male closes the mouth of the burrow with one of 
 its chelae, which is enormously developed; so that here it 
 indirectly serves as a means of defense. Their main use, 
 however, is probably to seize and to secure the female, and 
 this in some instances, as with Gammarus, is known to be 
 the case. The male of the hermit or soldier crab (Pagurus) 
 for weeks together, carries about the shell inhabited by the 
 female, f The sexes, however, of the common shore-crab 
 (Carcinus mcenas), as Mr. Bate informs me, unite directly 
 after the female has moulted her hard shell, when she is so 
 soft that she would be injured if seized by the strong 
 pincers of the male; but as she is caught and carried about 
 ty the male before moulting, she could then be seized with 
 impunity. 
 
 Fritz Miiller states that certain species of Melita are dis- 
 tinguished from all other amphipods by the females having 
 " the coxal lamellae of the penultimate pair of feet pro- 
 duced into hook-like processes, of which the males lay hold 
 with the hands of the first pair." The development of 
 these hook-like processes has probably followed from those 
 females which were the most securely held during the act 
 of reproduction, having left the largest number of offspring. 
 Another Brazilian amphipod (Orchestia Darwinii, fig. 8) 
 presents a case of dimorphism, like that of Tanais; for 
 there are two male forms, which differ in the struc- 
 ture of their chelae. J As either chela would certainly suf- 
 fice to hold the female for both are now used for this pur- 
 pose the two male forms probably originated by some 
 having varied in one manner and some in another ; 
 both forms having derived certain special, but nearly equal 
 advantages, from their differently shaped organs. 
 
 It is not known that male crustaceans fight together for 
 the possession of the females, but it is probably the case ; 
 for with most animals when the male is larger than the 
 female, he seems to owe his greater size to his ancestors 
 
 *"Hist. Nat. des Crust.," torn, ii, 1837, p. 50. 
 
 fMr. C. Spence Bate, "Brit. Assoc., Fourth Report on the Fauna 
 of S. Devon." 
 
 i Fritz Miiller, "Facts and Arguments for Darwin." 1869, pp. 
 25-28.
 
 304 
 
 THE DESCENT OF MAN. 
 
 having fought with other males during many generations. 
 In most of the orders, especially in the highest or the 
 Brachyura, the male is larger than the female ; the para- 
 sitic genera, however, in which the sexes follow different 
 
 Fig. 8. 
 
 Orchestia Darwinii (from Fritz Muller), showing the differently- 
 constructed chelai of the two male forms. 
 
 habits of life, and most of the Entomostraca must be 
 excepted. The chelee of many crustaceans are weapons 
 well adapted for fighting. Thus when a devil-crab (Por- 
 tunus puber) was seen by a son of Mr. Bate fighting with 
 a Carcinus mcenas, the latter was soon thrown on its back, 
 and had every limb torn from its body. When several
 
 CRUSTACEANS. 305 
 
 males of a Brazilian Gelasimus, a species furnished with 
 immense pincers, were placed together in a glass vessel by 
 Fritz Miiller, they mutilated and killed one another. Mr. 
 Bate put a large male Carcinus mcenas into a pan of 
 water, inhabited by a female which was paired with a 
 smaller male; but the latter was soon dispossessed. Mr. 
 Bate adds, " if they fought, the victory was a bloodless 
 one, for 1 saw no wounds." This same naturalist separated 
 a male sand-skipper (so common on our sea-shores), Gam- 
 mar us marinus, from its female, both of whom were 
 imprisoned in the same vessel with many individuals of the 
 same species. The female, when thus divorced, soon- 
 joined the others. After a time the male was put again 
 into the same veseel; and he then, after swimming about 
 for a time, dashed into the crowd, and without any fighting 
 at once took away his wife. This fact shows that in the 
 Amphipoda, an order low in the scale, the males and 
 females recognize each other and are mutually attached. 
 
 The mental powers of the Crustacea are probably higher 
 than at first sight appears probable. Any one who tries to 
 catch one of the shore-crabs, so common on tropical coasts, 
 will perceive how wary and alert they are. There is a large 
 crab (Birgus latro], found on coral islands, which makes a 
 thick bed of the picked fibers of the cocoanut, at the 
 bottom of' a deep burrow. It feeds on the fallen fruit of 
 this tree by tearing off the husk, fiber by fiber; and it 
 always begins at that end where the three eye-like depres- 
 sions are situated. It then breaks through one of these 
 eyes by hammering with its heavy front pincers, and, turn- 
 iiig round, extracts the albuminous core with its narrow 
 posterior pincers. But these actions are probably instinct- 
 ive, so that they would be performed as well by a young' 
 animal as by an old one. The following case, however, 
 can hardly be so considered: a trustworthy naturalist, Mr. 
 Gardner,* while watching a shore-crab (Gelasimus) making 
 its burrow, threw some shells toward the hole. One rolled 
 in, and three other shells remained within a few inches of 
 the mouth. In about five minutes the crab brought out 
 the shell which had fallen in, and carried it away to a dis- 
 
 *" Travels in the Interior of Brazil," 1846, p. 111. I have given in 
 my "Journal of Researches," p. 463, an account of the habits of the 
 Birgus.
 
 306 THE DESCENT OF MAN. 
 
 tance of a foot; it then saw the three other shells lying 
 near, and, evidently thinking that they might likewise roll 
 in, carried them to the spot where it had laid the first. It 
 would, I think, be difficult to distinguish this act from one 
 performed by man by the aid of reason. 
 
 Mr. Bate does not know of any well-marked case of dif- 
 ference of color in the two sexes of our British crustaceans, 
 in which respect, the sexes of the higher animals so often 
 differ. In son^ cases, however, the males and females differ 
 slightly in tint, but Mr. Bate thinks not more than may be 
 accounted for by their different habits of life; such as by 
 the male wandering more about, and being thus more 
 exposed to the light. Dr. Power tried to distinguish by 
 color the sexes of the several species which inhabit the 
 Mauritius but failed, except with one species of Squilla, 
 probably 8. stylifera, the male of which is described as 
 being "of a beautiful bluish-green/' with some of the 
 appendages cherry-red, while the female is clouded with 
 brown and gray, " with the red about her much less vivid 
 than in the male." * In this case we may suspect the 
 agency of sexual selection. From M. Bert's observation on 
 Daphnia, when placed in a vessel illuminated by a prism, 
 we have reason to believe that even the lowest crustaceans 
 can distinguish colors. With Sapliiriua (an oceanic genus 
 of Entoniostraca), the males are furnished with minute 
 shields or cell-like bodies, which exhibit beautiful changing 
 colors; these are absent in the females, and in both sexes 
 of one species, f It would, however, be extremely rash to 
 conclude that these curious organs serve to attract the 
 females. I am informed by Fritz Miiller, that in the 
 female of a Brazilian species of Gelasimus the whole body 
 is of a nearly uniform grayish-brown. In the male the 
 posterior part of the cephalo-thorax is pure white, with the 
 anterior part of a rich green, shading into dark brown; and 
 it is remarkable that these colors are liable to change in the 
 course of a few minutes the white becoming dirty gray or 
 even black, the green " losing much of its brilliancy." It 
 deserves especial notice that the males do not acquire their 
 bright colors until they become mature. They appear to 
 
 *Mr. Ch. Fraser, in "Proc. Zoolog. Soc.," 1869, p. 8. I am 
 indebted to Mr. Bate for Dr. Peer's statement. 
 fClaus, "Die freilebenden Copepoden," 1863, s. 35.
 
 SPIDERS. 307 
 
 be nmch more numerous than the females; they differ also 
 in the larger size of their chelae. In some species of the 
 genus, probably in all, the sexes pair and inhabit the same 
 burrow. They are also, as we have seen, highly intelligent 
 animals. From these various considerations it seems proba- 
 ble that the male in this species has become gayly orna- 
 mented in order to attract or excite the female. 
 
 It has just been stated that the male Gelasimus does not 
 acquire his conspicuous colors until mature and nearly 
 ready to breed. This seems a general rule in the whole 
 class in respect to the many remarkable structural differ- 
 ences between the sexes. We shall hereafter find the same 
 law prevailing throughout the great sub-kingdom of the 
 vertebrata; and in all cases it is eminently distinctive of 
 characters which have been acquired through sexual selec- 
 tion. Fritz Miiller * gives some striking instances of this 
 law; thus the male sand-hopper (Orchestia) does not, until 
 nearly full grown, acquire his large claspers, which are 
 very differently constructed from those of the female; while 
 young his claspers resemble those of the female. 
 
 Arachnida (Spiders). The sexes do not generally 
 differ much in color, but the males are often darker than 
 the females, as may be seen in Mr. Blackwall's magnificent 
 work.f In some species, however, the difference is con- 
 spicuous; thus the female of Sparassus smaragdulus is 
 dullish green, while the adult male has the abdomen of a fine 
 yellow, with three longitudinal stripes of rich red. In 
 certain species of Thomisns the sexes closely resemble each 
 other, in others they differ much; and analogous cases occur 
 in many other genera. It is often difficult to say which of 
 the two sexes departs most from the ordinary coloration of 
 the genns to which the species belong; but Mr. Blackwall 
 thinks that, as a general rule, it is the male; and CanestriniJ 
 remarks that in certain genera the males can be specifically 
 distinguished with ease, but the females with great difficulty. 
 
 *" Facts and Arguments," etc., p, 79. 
 
 f " A History of the Spiders of Great Britain," 1861-64. For the 
 following facts, see pp. 77, 88, 102. 
 
 \ This author has recently published a valuable essay on the 
 "Caratteri sessuali secondarii degli Arachnidi," in the " Atti della 
 Soc. Veneto-Trentina di Sc. Nat. Padova," vol. i, Fasc. 3, 1873.
 
 308 THE DESCENT OF MAN. 
 
 I am informed by Mr. Blackwall that the sexes while young 
 usually resemble each other; and both often undergo great 
 changes in color during their successive moults before 
 arriving at maturity. In other cases the male alone appears to 
 change color. Thus the male of the above bright-colored 
 Sparassus at first resembles the female, and acquires his pecu- 
 liar tints only when nearly adult. Spiders are possessed of 
 acute senses, and exhibit much intelligence; as is well 
 known, the females often show the strongest affection for 
 their eggs, which they carry about enveloped in a silken 
 web. The males search eagerly for the females, and have 
 been seen by Canestrini and others to fight for possession of 
 them. This same author says that the union of the two 
 sexes has been observed in about twenty species; and he 
 asserts positively that the female rejects some of the males 
 who court her, threatens them with open mandibles 
 and at last after long hesitation accepts the chosen one. 
 From these several considerations, we may admit with some 
 confidence that the well-marked differences in color between 
 the sexes of certain species are the results of sexual selection, 
 though we have not here the best kind of evidence the 
 display by the male of his ornaments. From the extreme 
 variability of color in the male of some species, for instance 
 of Theridion lineatum, it would appear that these sexual 
 characters of the males have not as yet become well fixed. 
 Canestrini draAvs the same conclusion from the fact that the 
 males of certain species present two forms, differing from 
 each other in the size and length of their jaws; and this 
 reminds us of the above cases of dimorphic crustaceans. 
 
 The male is generally much smaller than the female, 
 sometimes to an extraordinary degree,* and he is forced to 
 be extremely cautious in making his advances, as the 
 female often carries her coyness to a dangerous pitch. 
 De Geer saw a male that " in the midst of his preparatory 
 caresses was seized by the object of his attentions, envel- 
 oped by her in a web and then devoured, a sight which, as 
 
 * Aug. Vinson (" Araneides des lies de la Reunion," pi. vi, figs. 1 
 and 2) gives a good instance of the small size of the male, in Epeira 
 nigra. In this species, as I may add, the male is testaceous and the 
 female black with legs banded with red. Other even more striking 
 cases of inequality in size between the sexes have been recorded 
 (" Quarterly Journal of Science," 1868, July, p. 429); but I have not 
 Been the original accounts.
 
 SPIDERS. 309 
 
 he adds, filled him with horror and indignation."* The Rev. 
 0. P. Cambridge! accounts in the following manner for 
 the extreme smallness of the male in the genus Nephila: 
 " M. Vinson gives a graphic account of the agile way in 
 which the diminutive male escapes from the ferocity of the 
 female by gliding about and playing hide and seek over 
 her body and along her gigantic limbs. In such a pursuit 
 it is evident that the chances of escape would be in favor 
 of the smallest males, while the larger ones would fall 
 early victims; thus gradually a diminutive race of males 
 would be selected, until at last they would dwindle to the 
 smallest possible size compatible with the exercise of their 
 generative functions in fact, probaby to the size we now 
 see them, i. e., so small as to be a sort of parasite upon the 
 female, and either beneath her notice or too agile and too 
 small for her to catch without great difficulty." 
 
 Westring has made the interesting discovery that the 
 males of several species of TheridionJ have the power of 
 making a stridulating sound, while the females are mute. 
 The apparatus consists of a serrated ridge at the base of 
 the abdomen, against which the hard hinder part of the 
 thorax is rubbed; and of this structure not a trace can be 
 detected in the females. It deserves notice that several 
 writers, including the well known arachnologist Walck- 
 enaer, have declared that spiders are attracted by 
 music. From the analogy of the Orthoptera and Homop- 
 tera, to be described in the next chapter, we may feel 
 almost sure that the stridulation serves, as Westring also 
 believes, to call or to excite the female; and this is the first 
 case known to me in the ascending scale of the animal 
 kingdom of sounds emitted for this purpose. || 
 
 *Kirby and Spence, "Introduction to Entomology," vol. i, 1818, 
 p. 280. 
 
 f "Proc. Zoolog. Soc.," 1871, p. 621. 
 
 \ TJieridion (Asagena, Sund.) serratipes, ^-punctatum et guttatum; 
 see Westring, in Kroyer, " Naturhist. Tidskrift," vol. iv, 1842-1843, 
 p. 349; and vol. ii, 1846-1849, .p. 342. See, also, for other species, 
 " Araneae Suecicae," p. 184. 
 
 Dr. H. H. van Zouteveen, in liis Dutch translation of this work 
 (vol. i, p. 444), has collected several cases. 
 
 \ Hilge'ndorf, however, has lately called attention to an analogous 
 structure in some of the higher crustaceans, which seems adapted t 
 produce sound; see "Zoological Record," 1869, p. 603.
 
 310 THE DESCENT OF MAN. 
 
 Myriapoda. In neither of the two orders in this class, 
 the millipedes and centipedes, can I find any well-marked 
 instances of such sexual differences as more particularly 
 concern us. In Glomeris limbata, however, and perhaps 
 in some few other species, the males differ slightly in color 
 from the females; but this Glomeris is a highly variable 
 species. In the males of the Diplopoda, the legs belong- 
 ing either to one of the anterior or of the posterior seg- 
 ments of the body are modified into prehensile hooks 
 which serve to secure the female. In some species of 
 lulus the tarsi of the male are furnished with membranous 
 suckers for the same purpose. As we shall see when we 
 treat of insects, it is a much more unusual circumstance, 
 that it is the female in Lithobius, which is furnished with 
 prehensile appendages at the extremity of her body for 
 holding the male.* 
 
 *Walckenaer et P. Gervais, "Hist. Nat. des Insectes; Apteres," 
 torn, iv, 1847, pp. 17, 19, 68.
 
 INSECTS, 311 
 
 CHAPTER X. 
 
 SECONDARY SEXUAL CHARACTERS OF INSECTS. 
 
 Diversified structures possessed by the males for seizing the females 
 Differences between the sexes, of which the meaning is not 
 understood Difference in size between the sexes Thysanura 
 Diptera Heiniptera Homoptera, musical powers possessed 
 by the males alone Orthoptera, musical instruments of the 
 males, much diversified in structure; pugnacity; colors Neu- 
 roptera, sexual differences in color Hymenoptera, pugnacity 
 and colors Coleoptera, colors ; furnished with great horns, 
 apparently as an ornament; battles; stridulating organs gener- 
 ally common to both sexes. 
 
 IN the immense class of insects the sexes sometimes 
 differ in their locomotive-organs, and often in their sense- 
 organs, as in the pectinated and beautifully plumose anten- 
 nae of the males of many species. In Chloeon, one oJ the 
 Ephemera?, the male has great pillared eyes, of which the 
 female is entirely destitute* The ocelli are absent in the 
 females of certain insects, as in the Mutillidae; and here the 
 females are likewise wingless. But we are chiefly concerned 
 with structures by which one male is enabled' to conquer 
 another, either in battle or courtship, through his strength, 
 pugnacity, ornaments, or music. The innumerable contriv- 
 ances, therefore, by which the male is able to seize the 
 female, may be briefly passed over. Besides the complex 
 structures at the apex of the abdomen, which ought per 
 liaps to be ranked as primary organs,! " it is astonishing," as 
 
 *Sir J. Lubbock, "Transact. Linnean Soc.," vol. xxv, 1866, p. 
 484. With respect to the Mutillidae see Westwood, "Modern Class. 
 of Insects," vol. ii, p. 213. 
 
 | These organs in the male often differ in closely allied species 
 and afford excellent specific characters. But their importance, from 
 a functional point of view, as Mr. R. MacLachlan has remarked to 
 me, has probably been overrated. It has been suggested that slight 
 differences in these organs would suffice to prevent the intercrossing 
 of well-marked varieties or incipient species, and would thus aid in
 
 3151 
 
 THE DESCENT OF MAN. 
 
 Mr. B. D. Walsh* has remarked, " how many different 
 organs are worked hi by nature for the seemingly insignifi- 
 cant object of enabling the male to grasp the female 
 firmly." The mandibles or jaws are sometimes used for 
 this purpose; thus the male Corydalis cornutus (a neu- 
 ropterous insect in some degree allied to the dragon flies, 
 etc.) has immense curved jaws, 
 many times longer than those of 
 the female; and they are smooth 
 instead of being toothed, so that 
 he is thus enabled to seize her 
 without injury, f One of the 
 stag-beetles of ISTorth America 
 (Lucanus claphus) uses his jaws, 
 which are much larger than 
 those of the female, for the same 
 
 Eurpose but probably likewise 
 )r fighting. In one of the sand- 
 wasps (Ammophila) the jaws in 
 the two sexes are closely alike, 
 but are used for widely different 
 purposes; the males, as Prof. 
 Westwood observes, "are exceed- 
 ingly ardent, seizing their part- 
 ners round the neck with their 
 sickle-shaped jaws;"| while the 
 females use these organs for 
 burrowing in sand-banks and 
 making their nests. 
 The tarsi of the front legs are dilated in many male 
 beetles, or are furnished with broad cushions of hair; and 
 in many genera of water beetles they are armed with a 
 
 their development. That this can hardly be the case, we may infer 
 from the many recorded cases (see, for instance, Bronn, " Geschichte 
 der Natur," B. ii, 1843, s. 164; and Westwood, "Transact. Ent. 
 Soc.," vol. iii, 1842, p. 195) of distinct species having been observed 
 in union. Mr. MacLachlan informs me (vide " Stett. Ent. Zeitung," 
 1867, s. 155) that when several species of Phryganidae, which present 
 strongly pronounced differences of this kind, were confined together 
 by Dr. Aug. Meyer, they coupled, and one pair produced fertile ova. 
 
 *"The Practical Entomologist," Phila., vol. ii, May, 1867, p. 88. 
 
 f Mr. Walsh, ibid, p. 107. 
 
 ; " Modern Classification of Insects," vol. ii, 1840, pp. 205, 206. 
 Mr. Walsh, who called my attention to the double use of the jaws, 
 says that he has repeatedly observed this fact.
 
 INSECTS. 
 
 313 
 
 round flat sucker, so that the male may 
 adhere to the slippery body of the female. 
 It is a much more unusual circumstance 
 that the females of some water beetles (Dytis- 
 cus) have their elytra deeply grooved, and in 
 Acilius sulcatus thickly set with hairs as an 
 aid to the male. The females of some other 
 water beetles (Hydroporus) have their elytra 
 punctured for the same purpose.* In the 
 male of Crabro cribrarius (fig. 9) it is the 
 tibia which is dilated into a broad horny 
 plate with minute membraneous dots, giving 
 to it a singular appearance like that of a 
 riddle, f In the male of Peuthe (a genus 
 of beetles) a few of the middle joints of the 
 antennse are dilated and furnished on the 
 inferior surface with cushions of hair, ex- 
 actly like those on the tarsi of the Carabidae, 
 "and obviously for the same end." In 
 male dragon-flies, "the appendages at the 
 tip of the tail are modified in an almost in- 
 finite variety of curious patterns to enable 
 them to embrace the neck of the female." 
 Lastly, in the males of many insects, the 
 legs are furnished with peculiar spines, knobs 
 or spurs; or the whole leg is bowed or thick- 
 ened, but this is by no means invariably a 
 sexual character; or one pair, or all three 
 pairs are elongated, sometimes to an extrava- 
 gant length. J Fig. 10. Taphro- 
 
 The sexes of many species in all the orders ? e Sged) to UP* 
 present differences, of which the meaning is 
 not understood. One curious case is female. 
 
 per figure, male; 
 lower figure, 
 
 * We have here a curious and inexplicable caso of dimorphism, for 
 some of the females of four European species of Dysticus, and of 
 certain species of Hydroporus, have their elytra smooth; and no 
 intermediate gradations between the sulcated or punctured, and the 
 quite smooth elytra have been observed. See Dr. H. Schaum, as 
 quoted in 'the " Zoologist," vols. v-vi, 1847-43, p. 1896. Also Kirby 
 and Spence, "Introduction to Entomology," vol. iii, 1826, p. 305. 
 
 fWestwpod, "Modern Class.," vol. ii, p. 193. The following 
 statement about Penthe, and others in inverted commas, are taken 
 from Mr. Walsh, "Practical Entomologist," Phila., vol. iii, p. 88. 
 
 t Kirby and Spence, " Introduct.," *., vol. iii, pp. 333-336.
 
 314 THE DESCENT OF MAN. 
 
 that of the beetle (fig. 10), the male of which has 
 left mandible much enlarged; so that the mouth is 
 greatly distorted. In another Carabidous beetle, Euryg- 
 nathus,* we have the case, unique as far as known to Mr. 
 Wollaston, of the head of the female being much broader 
 and larger, though in a variable degree, than that of the 
 male. Any number of such cases could be given. They 
 abound in the Lepidoptera; one of the most extraordinary 
 is that certain male butterflies have their fore legs more or 
 less atrophied, with the tibiae and tarsi reduced to mere 
 rudimentary knobs. The wings, also, in the two sexes 
 often differ in neuration,f and sometimes considerably in 
 outline, as in the Aricoris epitus, which was shown to me 
 in the British Museum by Mr. A. Butler. The males of 
 certain South American butterflies have tufts of hair on 
 the margins of the wings and horny excrescences on the 
 disks of the posterior pair. J In several British butterflies, 
 as shown by Mr. Wonfor, the males alone are in parts 
 clothed with peculiar scales. 
 
 The use of the bright light of the female glow-worm has 
 been subject to much discussion. The male is feebly 
 luminous, as are the larvae and even the eggs. It has been 
 supposed by some authors that the light serves to frighten 
 away enemies, and by others to guide the male to the 
 female. At last Mr. Belt appears to have solved the 
 difficulty; he finds that all the Lampyridse which he has 
 tried are highly distasteful to insectivorous mammals and 
 birds. Hence it is in accordance with Mr. Bates' view, 
 hereafter to be explained, that many insects mimic the 
 Lampyridae closely, in order to be mistaken for them, and 
 thus to escape destruction. He further believes that the 
 luminous species profit by being at once recognized as 
 
 * " Insecta Maderensia," 1854, p. 20. 
 
 t E. Doubleday, " Annals and Mag. of Nat. Hist,," vol. i, 1848, p. 
 379. I may add that the wings in certain Hymenoptera (see Shuck - 
 ard, "Fossorial Hyinenop.," 1837, pp. 39-43) differ in neuration 
 according to sex. 
 
 JH. W. Bates, in "Journal of Proc. Linn. Soc.," vol. vi, 1862, p. 
 74. Mr. Wonfor's observations are quoted in " Popular Science 
 Keview," 1868, p, 343. 
 
 " The Naturalist in Nicaragua," 1874, pp. 816-320. On the phos- 
 phorescence of the eggs, see "Annals and Mag. of Nat. Hist.," 1871, 
 Nov., p. 872,
 
 INSECTS. 315 
 
 unpalatable. It is probable that the same explanation may 
 be extended to the Elaters, both sexes of which are highly 
 luminous. It is not known why the wings of the female 
 glow-worm have not been developed; but in her present 
 state she closely resembles a larva, and, as larva? are so 
 largely preyed on by many animals, we can understand why 
 she has been rendered so much more luminous and con- 
 spicuous than the male; and why the larva? themselves are 
 likewise luminous. 
 
 Difference in Size Between the Sexes. With insects of 
 all kinds the males are commonly smaller than the females; 
 and this difference can often be detected, even in the larval 
 state. So considerable is the difference between the male 
 and female cocoons of the silk-moth (Bombyx mori), that 
 in France they are separated by a particular mode of 
 weighing.* In the lower classes of the animal kingdom 
 the greater size of the females seems generally to depend 
 on their developing an enormous number of ova; and this 
 may to a certain extent hold good with insects. But Dr. 
 Wallace has suggested a much more probable explanation. 
 He finds, after carefully attending to the development of 
 the caterpillars of Bombyx cyntliia and yamamai, and espe- 
 cially to that of some dwarfed caterpillars reared from a 
 second brood on unnatural food, "that in proportion as 
 the individual moth is finer, so is the time required for its 
 metamorphosis longer; and for this reason the female, which 
 is the larger and heavier insect, from having to carry her 
 numerous eggs, will be preceded by the male, which is 
 smaller and has less to mature. "\ Now as most insects are 
 short-lived, and as they are exposed to many dangers, it 
 would manifestly be advantageous to the female to be im- 
 pregnated as soon as possible. This end would be gained 
 by the males being first matured in large numbers ready for 
 the advent of the females; and this again would naturally 
 follow, as Mr. A. R. Wallace has remarked, J through nat- 
 ural selection; for the smaller males would be first matured, 
 and thus would procreate a large number of offspring which 
 would inherit the reduced size of their male parents, while 
 
 *Robine"t, " Vers a Sole," 1848, p. 207. 
 
 t " Transact. Ent. Soc.," 3d series, vol. v, p. 486. 
 
 j " Journal of Proo. Ent. Soc.," f^b. 4, 18<J7, p. 71.
 
 316 THE DESCENT OF MAN. 
 
 the larger males, from being matured later, would leave 
 fewer offspring. 
 
 There are, however, exceptions to the rule of male insects 
 being smaller than the females; and some of these exceptions 
 are intelligible. Size and strength would be an advantage 
 to the males, which fight for the possession of the females; 
 and in these cases, as with the stag-beetle (Lucanus), the 
 males are larger than the females. There are, however, 
 other beetles which are not known to fight together, of which 
 the males exceed the females in size; and the meaning of this 
 fact is not known; but in some of these cases, as with the 
 huge Dyuastes and Megasoma, we can at least see that there 
 would be no necessity for the males to be smaller than the 
 females, in order to be matured before them, for these 
 beetles are not short-lived, and there would be ample time 
 for the pairing of the sexes. So again, male dragon-flies 
 (Libellulidse) are sometimes sensibly larger, and never 
 smaller, than the females;* and, as Mr. MacLachlan believes, 
 they do not generally pair with the females until a week or 
 fortnight has elapsed, and until they have assumed their 
 proper masculine colors. But the most curious case show- 
 ing on what complex and easily overlooked relations so 
 trifling a character as difference in size between the sexes 
 may depend, is that of the aculeate Hymenoptera; for Mr. 
 F. Smith informs me that throughout nearly the whole of 
 this large group, the males, in accordance with the general 
 rule, are smaller than the females, and emerge about a 
 week before them; but among the bees, the males of Apis 
 mellifica, Anthidium manicatum, and Antliophora acervo- 
 rum, and among the Fossores the males of the Methoca 
 ichneumonides are larger than the females. The explana- 
 tion of this anomaly is that a marriage flight is absolutely 
 necessary with these species, and the male requires great 
 strength and size in order to carry the female through the 
 air. Increased size has here been acquired in opposition to 
 the usual relation between size and the period of develop- 
 ment, for the males, though larger, emerge before the 
 smaller females. 
 
 We will now review the several orders, selecting such 
 facts as more particularly concern us. The Lepidoptera 
 
 * For this and other statements on the size of the sexes, see Kirby 
 and Spence, ibid., vol. iii, p. 300; on the duration of life in insects, 
 see p. 344.
 
 INSECTS. 317 
 
 (butterflies and moths) will be retained for a separate 
 chapter. 
 
 Thysanura. The members of this lowly organized 
 order are wingless, dull-colored, minute insects, with ugly, 
 almost misshapen heads and bodies. Their sexes do not 
 differ, but they are interesting as showing us that the males 
 pay sedulous court to the females even low down in the ani- 
 mal scale. Sir J. Lubbock* says: "it is very amusing to 
 see these little creatures (Smyntliurus luteus) coquetting 
 together. The male, which is much smaller than the 
 female, runs round her, and they butt one another, stand- 
 ing face to face and moving backward and forward like two 
 playful lambs. Then the female pretends to run away and 
 the male runs after her with a queer appearance of anger, 
 gets in front and stands facing her again; then she turns 
 coyly round, but he, quicker and more active, scuttles 
 round too, and seems to whip her with his antennas; then 
 for a bit they stand face to face, play with their antennae, 
 and seem to be all in all to one another. " 
 
 Diptera (Flies). The sexes differ little in color. The 
 greatest difference, known to Mr. F. Walker, is in the 
 genus Bibio, in which the males are blackish or quite 
 black, and the females obscure brownish-orange. The 
 genus Elaphomyia, discovered by Mr. Wallace f in New 
 Guinea, is highly remarkable, as the males are furnished 
 with horns, of which the females are quite destitute. The 
 horns spring from beneath the eyes, and curiously resemble 
 those of a stag, being either branched or jpalmated. In one 
 of the species they equal the whole body m length. They 
 might be thought to be adapted for fighting, but as in one 
 species they are of a beautiful pink color, edged with black, 
 with a pale central stripe, and as these insects have alto- 
 gether a very elegant appearance it is perhaps more proba- 
 ble that they serve as ornaments. That the males of some 
 Diptera fight together is certain; Prof. WestwoodJ has 
 several times seen this with the Tipulse. The males of 
 other Diptera apparently try to win the females by their 
 
 *" Transact. Linnean Soc.," vol. xxvi, 1868, p. 296. 
 
 f " The Malay Archipelago," vol. ii, 1869, p. 313. 
 
 j " Modern Classification of Insects," vol. ii. 1840, p. 526.
 
 318 THE DESCENT OF MAN. 
 
 music. H. Muller* watched for some time two males of an 
 Eristalis courting a female; they hovered above her, and 
 flew from side to side making a high humming noise at the 
 same time. Gnats and mosquitoes (Culicidas) also seem to 
 attract each other by humming; and Prof. Mayer has 
 recently ascertained that the hairs on the antenna of the 
 male vibrate in unison with the notes of a tuning-fork 
 within the range of the sounds emitted by the female. The 
 longer hairs vibrate sympathetically with the graver notes, 
 and the shorter hairs with the higher ones. Landois also 
 asserts that he has repeatedly drawn down a whole swarm 
 of gnats by uttering a particular note. It may be added 
 that the mental faculties of the Diptera are probably higher 
 than in most other insects, in accordance with their highly 
 developed nervous system, f 
 
 Hemiptera (Field Bugs). Mr. J. W. Douglas, who has 
 particularly attended to the British species, has kindly 
 given me an account of their sexual differences. The 
 males of some species are furnished with wings, while the 
 females are wingless; the sexes differ in the form of their 
 bodies, elytra, antenna and tarsi; but as the signification of 
 these differences is unknown they may be here passed over. 
 The females are generally larger and more robust than the 
 males. With British and, as far as Mr. Douglas knows, 
 with exotic species the sexes do not commonly differ much 
 in color; but in about six British species the male is con- 
 siderably darker than the female, and in about four other 
 species the female is darker than the male. Both sexes of 
 some species are beautifully colored; and as these insects 
 emit an extremely nauseous odor their conspicuous colors 
 may serve as a signal that they are unpalatable to insect- 
 ivorous animals. In some few cases their colors appear to 
 be directly protective ; thus Prof. Hoffmann informs me 
 that he could hardly distinguish a small pink and green 
 species from the buds on the trunks of lime-trees which 
 this insect frequents. 
 
 *Anwendung, etc., "Verh. d. n. V. Jahrg.," xxix, p. 80. Mayer, 
 in "American Naturalist," 1874, p. 236. 
 
 f See Mr. B. T. Lowne's interesting work, " On the Anatomy of the 
 Blow-fly, Musca vomitoria," 1870, p. 14. He remarks (p. 33) that 
 "the captured flies utter a peculiar plaintive note, and that this 
 sound causes other flies to disappear."
 
 INSECTS. 319 
 
 Some species of Eeduvidaemake a stridulating noise; and 
 in the case of Pirates stridulus this is said* to be effected 
 by the movement of the neck within the pro-thoracic 
 cavity. According to Westring, Reduvius personatns also 
 stridulates. But I have no reason to suppose that this is a 
 sexual character, excepting that with non-social insects 
 there seems to be no use for sound-producing organs unless 
 it be as a sexual call. 
 
 Homoptera. Every one who has wandered in a tropi- 
 cal forest must have been astonished at the din made 
 by the male Cicadse. The females are mute ; as the 
 Grecian poet Xenarchus says: "Happy the Cicadas live, 
 since they all have voiceless wives/' The noise thus made 
 could be plainly heard on board the " Beagle," when 
 anchored at a quarter of a mile from the shore of Brazil; 
 and Capt. Hancock says it can be heard at the distance of a 
 mile. The Greeks formerly kept, and the Chinese now 
 keep, these insects in cages for the sake of their song, so 
 that it must be pleasing to the ears of some men.f The 
 Cicadidae usually sing during the day, while the Fulgoridae 
 appear to be night-songsters. The sound, according to 
 Landois,J is produced by the vibration of the lips of the 
 spiracles, which are set in motion by a current of ajr 
 emitted from the tracheaa; but this view has lately been dis-' 
 puted. Dr. Powell appears to have proved that it is pro-; 
 duced by the vibration of a membrane set into action by a 
 special muscle. In the living insect, while stridulating, 
 this membrane can be seen to vibrate; and in the dead 
 insect the proper sound is heard, if the muscle, when a little 
 dried and hardened, is pulled with the point of a pin. In 
 the female the whole complex musical apparatus is present, 
 but is much less developed than in the male, and is never 
 used for producing sound. 
 
 With respect to the object of the music, Dr. Hartman, in 
 speaking of the Cicada septemdecim of the United States, 
 
 *Westwood, "Modern Class, of Insects," vol. ii, p. 473. 
 
 f These particulars are taken from Westwood's " Modern Class, of 
 Insects," vol. ii, 1840, p. 422. See also, on the Fulgoridae, Kirby 
 and Spence, " Introduct. ," vol. ii, p. 401. 
 
 J "Zeitschrift fiir wissenschaft Zoolog.," B. xvii, 1867, ss. 152-158. 
 
 "Transact. New Zealand Institute," vol. v, 1873, p. 286.
 
 320 THE DESCENT OF MAN. 
 
 says,* "the drums are now (June G and 7, 1851) heard in 
 all directions. This I believe to be the marital summons 
 from the males. Standing in thick chestnut sprouts about 
 as high as my head, where hundreds were around me, I 
 observed the females coming around the drumming males." 
 He adds, "this season (August, 1868) a dwarf pear-tree in 
 my garden produced about fifty larvae of Cic. pruinosa; and 
 I several times noticed the females to alight near a male 
 while he was uttering his clanging notes." Fritz Miiller 
 writes to me from S. Brazil that he has often listened to a 
 musical contest between two or three males of a species 
 with a particularly loud voice, seated at a considerable dis- 
 tance from each other; as soon as one had finished his song 
 another immediately began and then another. As there is 
 BO much rivalry between the males, it is probable that the 
 females not only find them by their sounds, but that, like 
 female birds, they are excited or allured by the male with 
 the most attractive voice. 
 
 I have not -heard of any well-marked cases of ornamental 
 differences between the sexes of the Homoptera. Mr. 
 Douglas informs me that there are three British species, in 
 which the male is black or marked with black bands, while 
 the females are pale-colored or obscure. 
 
 Orthoptera (Crickets and Grasshoppers). The males in 
 the three saltatorial families in this order are remarkable 
 for their musical powers, namely the Achetidae or crickets, 
 the Locustidae, for which there is no equivalent English 
 name, and the Acridiida? or grasshoppers. The stridula- 
 tion produced by some of the Locustidas is so loud that 
 it can be heard during the night at the distance of a 
 mile;f and that made by certain species is not unmusical 
 even to the human ear, so that the Indians on the Amazons 
 keep them in wicker cages. All observers agree that the 
 sounds serve either to call or excite the mute females. 
 With respect to the migratory locusts of Eussia, Korte has 
 given \ an interesting case of selection by the female of a 
 
 * I am indebted to Mr. Walsh for having sent me this extract from 
 a " Journal of the Doings of Cicada septemdecim," by Dr. Hartman. 
 
 f L. Guilding, "Transact. Linn. Soc.," vol. xv, p. 154. 
 
 \ I state this on the authority of Koppen, " Ueber die Heuschrecken 
 in Siidrussland," 1866, p. 82, for I have in vain endeavored to pro 
 cure Korte's work.
 
 INSECTS. 
 
 321 
 
 male. The males of this species (PacTiytylus migratorius) 
 while coupled with the female stridulate from anger or 
 jealousy if approached by other males. The house-cricket 
 when surprised at night uses its voice to warn its fellows.* 
 In North America the Katydid (Platyphyllum concavum, 
 one of the Locustidae) is described f as mounting on the 
 upper branches of a tree, and in the evening beginning 
 "his noisy babble, while rival notes issue from the neigh- 
 boring trees, and the groves resound with the call of 
 Katy - did - she - did the live- 
 long night." Mr. Bates, in 
 speaking of the European 
 field-cricket (one of the Ache- 
 tidas), says "the male has been 
 observed to place himself in 
 the evening at the entrance 
 of his burrow, and stridulate 
 until a female approaches, 
 when the louder notes are 
 succeeded by a more subdued 
 tone, while the successful 
 musician caresses with his 
 antennae the mate he has 
 won/'J Dr. Scudder was able 
 to excite one of these insects 
 to answer him, by rubbing on showing the teetn, st, 
 a file with a quill. In both Le w\n^ ve? U with Up t P h e e r 
 sexes a remarkable auditory 
 apparatus has been discovered 
 by Von Siebold, situated in the front legs. | 
 
 In the three families the sounds are differently produced. 
 In the males of the Achetidae both wing-covers have the 
 same apparatus; and this in the field-cricket (Gryllus 
 campestris, fig. 11) consists, as described by Landois,!" of 
 
 * Gilbert White, " Nat. Hist, of Selborne," vol. ii, 1825, p. 262. 
 
 f Harris, " Insects of New England," 1842, p. 128. 
 
 J" The Naturalist on the Amazons," vol. i, 1863, p. 252. Mr, 
 Bates gives a very interesting discussion on the gradations in the 
 musical apparatus of the three families. See also Westwood, " Mod- 
 ern Class.," vol. ii, pp. 445, 453. 
 
 | " Pr6c. Boston Soc. of Nat. Hist.," vol. xi, April, 1868. 
 
 ("Nouveau Manuel d'Anat. Cornp." (French translat.), torn, i, 
 1850, p. 567. 
 
 t" Zeitscurift fur wissenscliaft. Zoolog.," B. xvii, 1867, s. 117. 
 
 Fig. 11. Gryllus campestris (from 
 
 Landois). 
 
 Right-hand figure, under side of part 
 of a wing-nervure, much magnified, 
 showing the teeth, st, 
 
 surface of 
 
 smooth nervure, r, across w 
 teeth (st) are scraped. 
 
 projecting, 
 hich the
 
 322 THE DESCENT OF MAN. 
 
 from 131 to 138 sharp, transverse ridges or teeth (st) on 
 the under side of one of the nervures of the wing-coyer. 
 This toothed nervure is rapidly scraped across a projecting, 
 smooth, hard nervure (r) on the upper surface of the oppo- 
 site wing. First one wing is rubbed over the other, and 
 then the movement is reversed. Both wings are raised a 
 little at the same time, so as to increase the resonance. In 
 some species the wing-covers of the males are furnished at 
 the base with a talc-like plate.* I here give a drawing 
 (fig. 12) of the teeth on the under side of the nervure of 
 another species of Gryllus, viz., G. domesticus. With 
 respect to the formation of these teeth, Dr. Gruber has 
 shown f that they have been developed by the aid of 
 selection, from the minute scales and hairs 
 with which the wings and body are covered, 
 and I came to the same conclusion with 
 respect to those of the Coleoptera. But Dr. 
 Gruber further shows that their development 
 is in part directly due to the stimulus from 
 the friction of one wing over the other. 
 
 In the Locustidae the opposite wing-covers 
 differ from each other in structure (fig 13), 
 and the action cannot, as in the last family, 
 i u s domesticus be reversed. The left Aving, which acts as the 
 ois) - bow, lies over the right wing which serves as 
 the fiddle. One of the nervures (a) on the under surface of 
 the former is finely serrated, and is scraped across the 
 prominent nervures on the upper surface of the opposite or 
 right wing. In our British Phasgonura viridissima it 
 appeared to me that the serrated nervure is rubbed against 
 the rounded hind-corner of the opposite wing, the edge of 
 which is thickened, colored brown, and very sharp. In 
 the right wing, but not in the left, there is a little plate, as 
 transparent as talc, surrounded by nervures, and called the 
 speculum. In Ephippiger vitium, a member of this same 
 family, we have a curious subordinate modification; for the 
 wing-covers are greatly reduced in si/e, but " the posterior 
 part of the pro-thorax is elevated into a kind of dome over 
 
 * Westwood, " Modern Class, of Insects," vol. i, p. 440. 
 t " Ueber der Tonapparat der Locustiden, ein Beitrag zuin Darwin- 
 jsmus," "Zeitscu. fur wissensch Zoolog.," B. xxii, 1872, p. 100.
 
 INSECTS.. 333 
 
 the wing-covers, and which has probably the effect of 
 increasing the sound."* 
 
 We thus see that the musical apparatus is more dif- 
 ferentiated or specialized in the Locustidse (which 
 include, I believe, the most powerful performers in 
 
 Big. 18. Chloroccelus Tanana (from Bates), a, 5. Lobes of opposite wing-covers. 
 
 the order), and in the Achetidae, in which both wing- 
 covers ^ have the same structure and the same functipn.f 
 Landois, however, -detected in one of the Locustidse, 
 namely in Decticus, a short and narrow row of small 
 teeth, mere rudiments, on the inferior surface of the 
 right wing-cover, which underlies the other and is never 
 used as the bow. I observed the same rudimentary 
 structure on the under side of the right wing- 
 cover in Phasgonura viridissima. Hence we may infer 
 with confidence that the Locustidse are descended from a 
 form in 'which, as in the existing Achetidae, both wiiig- 
 
 *Westwood, "Modern Class, of Insects," vol. i, p. 453, 
 
 f Landois, " Zeitsch. f. wiss Zoolog." B. xvii, 1867, ss. 121, 122.
 
 324 
 
 THE DESCENT OF MAN. 
 
 covers had serrated nervures on the under surface and could 
 be indifferently used as the bow; but that in the Locustidae 
 the two wing-covers gradually became differentiated and 
 perfected on the principle of the division of labor, the one 
 to act exclusively as the bow and the other as the fiddle. 
 Dr. Gruber takes the same view, and has shown that rudi- 
 mentary teeth are commonly found on the inferior surface 
 of the right wing. By what steps the more simple appa- 
 ratus in the Achetidse originated we do not know, but it is 
 probable that the basal portions of the wing-covers origi- 
 nally overlapped each other as they do at present; and that 
 the friction of the nervures 
 produced a grating sound as 
 is now the case with the wing- 
 covers of the females.* A 
 grating sound thus occasion- 
 ally and accidentally made by 
 the males, if it served them ever 
 so little as a love-call to the fe- 
 males, might readily have been 
 intensified through sexual se- 
 lection by variations in the 
 roughness of the nervures hav- 
 ing been continually preserved. 
 
 4. Hind-leg of Stenobotbrus pra- ln the last and third family, 
 m. r, the stimulating ridge ; uainelv, the AcndlldEB Or 
 
 grasshoppers, the stridulation 
 is produced in a very differ- 
 ent manner, and according to Dr. Scudder, is not so shrill 
 as in the preceding families. The inner surface of the 
 femur (fig. 14, r) is furnished with a longitudinal row of 
 minute, elegant, lancet-shaped, elastic teeth from eighty- 
 five to ninety-three in number;f and these are scraped 
 across the sharp, projecting nervures on the wing-covers 
 which are thus made to vibrate and resound. Harris! says 
 that when one of the males begins to play he first " bends 
 the shank of the hind-leg beneath the thigh, where it is 
 
 *Mr. Walsh also informs me that he has noticed that the female 
 of the Platyphyttum c&ncavum, "when captured, makes a feeble 
 grating noise by shuffling her wing-covers together." 
 
 fLandois, ibid., s. 113. 
 
 j" Insects of New England," 1842, p. 133.
 
 INSECTS. 
 
 lodged in a furrow designed to receive it, and then draws 
 the leg briskly up and down. He does not play both 
 fiddles together, but alternately, first upon one and then 
 on the other." In many species the base of the abdomen 
 is hollowed out into a great cavity which is believed to act 
 as a resounding board. In Pneumora (fig. 15), a S. Afri- 
 
 Flg. 15. Pneumora (from 
 figure, 
 
 3imens in the British Museum), 
 per figure, female. 
 
 Upper 
 
 can genus belonging to the -same family, we meet with a 
 new and remarkable modification; in the males a small 
 notched ridge projects obliquely from each side of the 
 abdomen, against which the hind femora are rubbed.* As 
 the male is furnished with wings (the female being wing- 
 
 * Westwood, "Modern Classification," vol. i, p. 462.
 
 326 THE DESCENT OF MAN. 
 
 less) it is remarkable that the thighs are not rubbed in the 
 usual manner against the wing-covers; but this may per- 
 haps be accounted for by the unusually small size of the 
 hind legs. I have not been able to examine the inner sur- 
 face of the thighs, which, judging from analogy, would be 
 finely serrated. The species of Pneumora have been more 
 profoundly modified for the sake of stridulation than any 
 other orthopterous insect; for in the male the whole body 
 has been converted into a musical instrument, being dis- 
 tended with air like a great pellucid bladder so as to 
 increase the resonance. Mr. Trimen informs me that at 
 the Cape of Good Hope these insects make a wonderful 
 noise during the night. 
 
 In the three foregoing families the females are almost 
 always destitute of an efficient musical apparatus. But there 
 are a few exceptions to this rule, for Dr. Gruber has shown 
 that both sexes of EpMppiger vitium are thus provided; 
 though the organs differ in the male and female to a cer- 
 tain extent. Hence we cannot suppose that they have been 
 transferred from the male to the female, as appears to have 
 been the case with the secondary sexual characters of many 
 other animals. They must have been independently devel- 
 oped in the two sexes, which no doubt mutually call to 
 each other during the season of love. In most other Locus- 
 tidas (but not according to Landois in Decticirs) the females 
 have rudiments of the stridulatory organs proper to the 
 male; from whom it is probable that these have been trans- 
 ferred. Landois also found such rudiments on the under 
 surface of the wing-covers of the female Achetidas, and on 
 the femora of the female Acridiidae. In the Homoptera, 
 also, the females have the proper musical apparatus in a 
 functionless state; and we shall hereafter meet, in other 
 divisions of the animal kingdom, with many instances of 
 structures proper to the male being present in a rudimentary 
 condition in the female. 
 
 Landois has observed another important fact, namely, 
 that in the females of the Acridiidas, the stridulating teeth 
 on the femora remain throughout life in the same condition 
 in which they first appear during the larval state in both 
 Hexes. In the males, on the hand, they become further 
 developed, and acquire their perfect structure at the last 
 moult, when the insect is mature and ready to breed. 
 
 From the facts now given we see that the means by
 
 INSECTS. 327 
 
 which the males of the Orthoptera produce their sounds are 
 extremely diversified, and are altogether different from 
 those employed by the Homoptera.* But throughout the 
 animal kingdom we often find the same object gained by 
 the most diversified means; this seems due to the whole 
 organization having undergone multifarious changes in the 
 course of ages, and as part after part varied different varia- 
 tions were taken advantage of for the same general purpose. 
 The diversity of means for producing sound in the three 
 families of the Orthoptera and in the Homoptera, 
 impresses the mind with the high importance of these 
 structures to the males, for the sake of calling or alluring 
 the females. We need feel no surprise at the amount of 
 modification which the Orthoptera have undergone in this 
 respect, as we new know, from Dr. Scudder's remarkable 
 discovery,! that there has been more than ample time. 
 This naturalist has lately found a fossil insect in the 
 Devonian formation of New Brunswick, which is furnished 
 with " the well-known tympanum or stridulating apparatus 
 of the male Locustida3." The insect, though in most 
 respects related to the Neuroptera, appears, as is so often 
 the case with very ancient forms, to connect the two related 
 orders of the Neuroptera and Orthoptera. 
 
 I have but little more to say on the Orthoptera. Some 
 of the species are very pugnacious; when two male field- 
 crickets (Gryllus campestris) are confined together they 
 fight till one kills the other; and the species of Mantis are 
 described as maneuvering with their sword-like front limbs, 
 like hussars with their sabers. The Chinese keep these 
 insects in little bamboo cages, and match them like game- 
 cocks. J "With respect to color, some exotic locusts are 
 beautifully ornamented; the posterior wings being marked 
 with red, blue and black; but as throughout the order the 
 sexes rarely differ much in color, it is not probable that 
 they owe their bright tints to sexual selection. Conspicu- 
 
 * Landois has recently found in certain Orthoptera rudimentary 
 structures closely similar to the sound-producing organs in the 
 Homoptera; and this is a surprising fact. See "Zeitschr. fiir wis- 
 sensch. Zoolog.," B. xxii, Heft 3, 1871, p. 348. 
 
 f " Transact. Ent. Soc.," 3d series, vol. ii. (" Journal of Proceed- 
 ings," p. 117.) 
 
 t Westwood, " Modern Class of Insects," vol. i, p, 427; for crick- 
 ets, p. 445.
 
 328 THE DESCENT OF MAN. 
 
 ous colors may be of use to these insects by giving notice 
 that they are unpalatable. Thus it has been observed* that 
 a bright-colored Indian locust was invariably rejected when 
 offered to birds and lizards. Some cases, however, are 
 known of sexual differences in color in this order. The 
 male of an American cricket f is described as being as 
 white as ivory, while the female varies from almost white to 
 greenish-yellow or dusky. Mr. Walsh informs me that the 
 adult male of Spectrum femoratum (one of the Phasmidae) 
 " is of a shining brownish-yellow color; the adult female 
 being of a dull, opaque, cinereous brown; the young of 
 both sexes being green. " Lastly, I may mention that the 
 male of one curious kind of cricket J is furnished with " a 
 long membranous appendage, which falls over the face like 
 a veil;" but what its use may be is not known. 
 
 Neuroptera. Little need here be said, except as to color. 
 In the Ephemericlge the sexes often differ slightly in their 
 obscure tints ; but it is not probable that the males are 
 thus rendered attractive to the females. The Libellulidae 
 or dragon-flies are ornamented with splendid green, blue, 
 yellow, and vermilion metallic tints; and the sexes often 
 differ. Thus, as Prof. Westwood remarks,,! the males 
 of some of the Agrionidse, "are of a rich blue with black 
 wings, while the females are fine green with colorless 
 wings." But in Agrion Ratnburii these colors are exactly 
 reversed in the two sexes. 1" In the extensive North Ameri- 
 can genus of Hetasrina, the males alone have a beautiful 
 carmine spot at the base of each wing. In Anax junius 
 the basal part of the abdomen in the male is a vivid ultra- 
 marine blue, and in the female grass-green. In the allied 
 genus Gomphus, on the other hand, and in some other 
 genera, the sexes differ but little in color. In closely-allied 
 
 *Mr. Ch. Home, in Proc. Ent. Soc.," May 3, 1869, p. 12. 
 
 f The (Ecantlius nivalis. Harris, " Insects of New England," 1842, 
 p. 124. The two sexes of the (E. pellucidus of Europe differ, as I 
 hear from Victor Carus, in nearly the same manner. 
 
 | Platyblemnus; Westwood, "Modern Class.," vol. i, p. 447. 
 
 B. D. Walsh, the " Pseudoneuroptera of Illinois," in " Proc. Ent. 
 Soc. of Philadelphia," 1862, p. 361. 
 
 | " Modern Class.," vol. ii, p. 37. 
 
 IWalsh, ibid., p. 381. I am indebted to this naturalist for the fol- 
 lowing facts on Hetaerina, Anax and Gomphus.
 
 INSECTS. 329 
 
 forms throughout the animal kingdom similar cases of the 
 Bexes differing greatly, or very little, or not at all, are of 
 frequent occurrence. Although there is so wide a differ- 
 ence in color between the sexes of many Libellulidae, it is 
 often difficult to say which is the more brilliant; and the 
 ordinary coloration of the two sexes is reversed, as we have 
 just seen, in one species of Agrion. It is not probable that 
 their colors in any case have been gained as a protection. 
 Mr. MacLachlan, who has closely attended to this family, 
 writes to me that dragon-flies the tyrants of the insect- 
 world are the least liable of any insect to be attacked by 
 birds or other enemies, and he believes that their bright 
 colors serve as a sexual attraction. Certain dragon-flies 
 apparently are attracted by particular colors; Mr. Patterson 
 observed* that the Agrionidae, of which the males are blue, 
 settled in numbers on the blue float of a fishing line; while 
 two other species were attracted by shining white colors. 
 
 It is an interesting fact, first noticed by Schelver, that, 
 in several genera belonging to two sub-families, the males 
 on first emergence from the pupal state, are colored exactly 
 like the females ; but that their bodies in a short time 
 assume a conspicuous milky-blue tint, owing to the exuda- 
 tion of a kind of oil, soluble in ether and alcohol. Mr. 
 MacLachlan believes that in the male of Libellula depressa 
 this change of color does not occur until nearly a fortnight 
 after the metamorphosis, when the sexes are ready to pair. 
 
 Certain species of Neurothemis present, according to 
 Brauer,f a curious case of dimorphism, some of the 
 females having ordinary wings, while others have them 
 <e very richly netted, as in the males of the same species." 
 Brauer "explains the phenomenon on Darwinian principles 
 by the supposition that the close netting of the veins is a 
 secondary sexual character in the males, which has been 
 abruptly transferred to some of the females, instead of, as 
 generally occurs, to all of them." Mr. MacLachlan 
 informs me of another instance of dimorphism in sev- 
 eral species of Agrion, in which some individuals are 
 of an orange color, and these are invariably females. 
 This is probably a case of reversion ; for in the 
 true Lib,ellulae, when the sexes differ in color, the females 
 
 * "Transact. Ent. Soc.," vol. i, 1836, p. 81. 
 
 f See abstract in the "Zoological Record " for 1867, p. 450.
 
 330 THE DESCENT OF MAN. 
 
 are orange or yellow; so that supposing Agrion to be 
 descended from some primordial form which resembled the 
 typical Libullulae in its sexual characters, it would not be 
 surprising that a tendency to vary in this manner should 
 occur in the females alone. 
 
 Although many dragon-flies are large, powerful and fierce 
 Insects, the males have not been observed by Mr. Mac- 
 Lachlan to fight together, excepting, as he believes, in some 
 of the smaller species of Agrion. In another group in this 
 order, namely, the Termites or white ants, both sexes at 
 the time of swarming may be seen running about, "the 
 male after the female, sometimes two chasing one female, 
 and contending with great eagerness who shall win the 
 prize."* The Atropos pulsatorius is said to make a noise 
 with its jaws, which is answered by other individuals, f 
 
 Hymenoptera. That inimitable observer, M. Fabre, { in 
 describing the habits of Cerceris, a wasp-like insect, 
 remarks that " fights frequently ensue between the males 
 for the possession of some particular female, who sits an 
 apparently unconcerned beholder of the struggle for suprem- 
 acy, and when the victory is decided, quietly flies away in 
 company with the conqueror." AVestwood says that the 
 males of one of the saw-flies (Tenthredina?) "have been 
 found fighting together with their mandibles locked. " As 
 M. Fabre speaks of the males of Cerceris striving to obtain 
 a particular female, it may be well to bear in mind that 
 insects belonging to this order have the power of recogniz- 
 ing each other after long intervals of time, and are deeply 
 attached. For instance, Pierre Huber, whose accuracy no one 
 doubts, separated some ants, and when, after an interval of 
 four months, they met others which had formerly belonged 
 to the same community, they recognized and caressed one 
 another with their antennae. Had they been strangers they 
 would have fought together. Again, when two commu- 
 nities engage in a battle the ants on the same side sorne- 
 
 Kirby and Spence, " Introduct, to Entomology," vol. ii, 1818, 
 p 85. 
 
 fHouzeau, " Les Facultes Mentales," etc., torn, i, p. 104. 
 
 j See an interesting article, "The Writings of Fabre," in "Nat 
 Hist. Review," April, 1862, p. 122, 
 
 "Journal of Proc. of Eutoinolog. Soc.," Sept. 7, 1863, p. 169.
 
 INSECTS. 331; 
 
 times attack each other in the general confusion, but they 
 soon perceive their mistake, and the one ant soothes the 
 other.* 
 
 In this order slight differences in color, according to sex, 
 are common, but conspicuous differences are rare except in 
 the family of bees; yet both sexes of certain groups are so 
 brilliantly colored for instance in Chrysis, in which ver- 
 milion and metallic greens prevail that we are tempted to 
 attribute the result to sexual selection. In the Ichneu- 
 monidae, according to Mr. Walsh, f the males are almost 
 universally lighter-colored than the females. On the other 
 hand, in the Tenthredinidse the males are generally darker 
 than the females. In the Siricidae the sexes frequently 
 differ; thus the male of Sirex juvencus is banded with 
 orange, while the female is dark purple; but it is difficult 
 to say which sex is the more ornamented. In Tremex 
 columbce the female is much brighter colored than the 
 male. I am informed by Mr. F. Smith that the male 
 ants of several species are black, the females being 
 testaceous. 
 
 In the family of bees, especially in the solitary species, 
 as I hear from the same entomologist, the sexes often differ 
 in color. The males are generally the brighter, and in 
 Bombus as well as in Apathus, much more variable in color 
 than the females. In Anthophora retusa the male is of a 
 rich fulvous-brown, while the female is quite black; so are 
 the females of several species of Xylocopa, the males being 
 bright yellow. On the other hand the females of some 
 species, as of A ndrcena fiilva, are much brighter colored 
 than the males. Such differences in color can hardly be 
 accounted for by the males being defenseless and thus 
 requiring protection, while the females are well defended 
 by their stings. H. Miiller,J who has particularly attended 
 to the habits of bees, attributes these differences in color in 
 chief part to sexual selection. That bees have a keen per- 
 ception of color is certain. He says that the males search 
 eagerly and fight for the possession of the females; and he 
 
 *P. Huber, " Recherches sur les Moeurs des Fourmis," 1810, pp, 
 150, 165. 
 
 f " Proc. Entomolog. Soc. of Philadelphia," 1866, pp. 238, 239. 
 
 \ " Anwendung der Darwinschen Lehre auf Bienen." Verb. d. n. 
 Jahrg., xxix.
 
 332 THE DESCENT OF MAN. 
 
 accounts through such contests for the mandibles of the 
 males being in certain species larger than those of the 
 females. In some cases the males are far more numerous 
 than the females, either early in the season, or at all times 
 and places, or locally; whereas the females in other cases 
 are apparently in excess. In some species the more beauti- 
 ful males appear to have been selected by the females; and 
 in others the more beautiful females by the males. Conse- 
 quently in certain genera (Muller, p. 42) the males of the 
 several species differ much in appearance, while the females 
 are almost indistinguishable; in other genera the reverse 
 occurs. H. Muller believes (p. 82) that the colors gained 
 by one sex through sexual selection have often been trans- 
 ferred in a variable degree to the other sex, just as the 
 pollen-collecting apparatus of the female has often been 
 transferred to the male, to whom it is absolutely useless.* 
 
 Mutilla Europcea makes a stridulating noise; and accord- 
 ing to Goureau f both sexes have this power. He attributes 
 the sound to the friction of the third and preceding 
 abdominal segments, and I find that these surfaces are 
 marked with very fine concentric ridges; but so is the pro- 
 jecting thoracic collar into which the head articulates, and 
 this collar, when scratched with the point of a needle, 
 emits the proper sound. It is rather surprising that both 
 sexes should have the power of stridulating, as the male is 
 
 *M. Perrier in his article " la Selection sexuelle d'apres Darwin" 
 (" Revue Scientifique," Feb., 1873, p. 868), without apparently having 
 reflected much on the subject, objects that as the males of social bees 
 are known to be produced from unfertilized ova, they could not trans- 
 mit new characters to their male offspring. This is an extraordinary 
 objection. A female bee fertilized by a male, which presented some 
 character facilitating the union of the sexes, or rendering him more 
 attractive to the female, would lay eggs which would produce only 
 females; but these young females would next year produce males ; 
 and will it be pretended that such males would not inherit the char- 
 acters of their male grandfathers? To take a case with ordinary ani- 
 mals as nearly parallel as possible; if a female of any white quad- 
 ruped or bird were crossed by a male of a black breed, and the male 
 and female offspring were paired together, will it be pretended that 
 the grandchildren would not inherit a tendency to blackness from 
 their male grandfather? The acquirement of new characters by the 
 sterile worker-bees is a much more difficult case, but I have endeav- 
 ored to show in my " Origin of Species " how these sterile beings are 
 subjected to the power of natural selection. 
 
 f Quoted by Westwood, "Modern Class, of Insects," vol. li, p. 214
 
 INSECTS. 333 
 
 winged and the female wingless. It is notorious that bees 
 express certain emotions, as of anger, by the tone of their 
 humming; and according to H. Miiller (p. 80) the males 
 of some species make a peculiar singing noise while pursu- 
 ing the females. 
 
 Coleoptera (Beetles). Many beetles are colored so as to 
 resemble the surfaces which they habitually frequent, and 
 they thus escape detection by their enemies. Other species, 
 for instance diamond-beetles, are ornamented with splendid 
 colors, which are often arranged in stripes, spots, crosses 
 and other elegant patterns. Such colors can hardly serve 
 directly as a protection except in the case of certain flower- 
 feeding species; but they may serve as a warning or means 
 of recognition on the same principle as the phosphorescence 
 of the glow-worm. As with beetles the colors of the two 
 sexes are generally alike, we have no evidence that they 
 have been gained through sexual selection; but this is at 
 least possible, for they may have been developed in one sex 
 and then transferred to the other; and this view is even in 
 some degree probable in those groups which possess other 
 well-marked secondary sexual characters. Blind beetles, 
 which cannot of course behold each other's beauty, never, 
 as I hear from Mr. Waterhouse, Jr,, exhibit bright colors, 
 though they often have polished coats; but the explanation 
 of their obscurity may be that they generally inhabit caves 
 and other obscure stations. 
 
 Some Longicorns, especially certain Prionidse, offer an 
 exception to the rule that the sexes of beetles do not differ 
 in color. Most of these insects are large and splendidly 
 colored. The males in the genus Pyrodes,* which I saw 
 
 * Pyrodes pulcherrimus, in which the sexes differ conspicuously, 
 has been described by Mr. Bates in !< Transact. Ent. Soc.," 1869, p. 
 50. I will specify the few other cases in which I have heard of a 
 difference in color between the sexes of beetles. Kirby and Spence 
 ("Introduct. to Entomology," vol. iii, p. 301) mention a Cantharis, 
 Meloe, Rhagiurn, and the "Leptura testacea ; the male of the latter 
 being testaceous, with a black thorax, and the female of a dull red 
 all over. These two latter beetles belong to the family of Longi- 
 corns. Messrs. R. Trimen and Waterhouse junior inform me of two 
 Lamellicorns, viz., a Peritrichia and Trichius, the male of the latter 
 being more obscurely colored than the female. In Tillus elongatus 
 the male-is black, and the female always, as it is believed, of a dark 
 blue color, with a red thorax. The male, also, of Orsodac.ia atra, as 
 I hear from Mr. Walsh, is black, the female (the so called 0. 
 lis) having a rufous thorax.
 
 334 
 
 THE DESCENT OF MAN. 
 
 in Mr, Bates' collection, are generally redder but rather 
 duller than the females, the latter being colored of a more 
 or less splendid golden-green. On the other hand, in one 
 species the male is golden-green, the female being richly 
 tinted with red and purple. In the genus Esmeralda the 
 sexes differ so greatly in color that they have been ranked 
 as distinct species; in one species both are of a beautiful 
 shining green, but the male has a red thorax. On the 
 whole, as far as I could judge, the females of those 
 Prionidae, in which the sexes differ, are colored more richly 
 than the males, and this does not accord with the common 
 rule in regard to color when acquired through sexual 
 selection. 
 
 A most remarkable distinction between the sexes of many 
 beetles is presented by the great horns which rise from the 
 head, thorax and clypeus of the males; and in some few 
 cases from the under surface of the body. These horns 
 in the great family of the Lamellicorns, resemble those of 
 various quadrupeds, such as stags, rhinoceroses, etc,, and 
 are wonderful both from their size and diversified shapes. 
 Instead of describing them, I have given figures of the 
 males and females of some of the more remarkable forms. 
 (Figs. 16 to 20.) The females generally exhibit rudiments 
 
 Frg. 16. Chalcosoma atlas. Upper figure, male (reduced); lower figure, female 
 (natural size).
 
 INSECTS. 
 
 335 
 
 Fig. 17, Copris isidis. (Left-hand figures, males.) 
 
 Fig. 19. 
 
 Dipelicus cantori: 
 
 Onthophagus rangifer, enlarged.
 
 336 THE DESCENT OF MAN. 
 
 of the horns in the form of small knobs or ridges; but some 
 are destitute of even the slightest rudiment. On the other 
 hand, the horns are nearly as well developed in the female 
 as in the male of Phanceus lancifer; and only a little less 
 well developed in the females of some other species of this 
 genus and of Copris. I am informed by Mr. Bates that 
 the horns do not differ in any manner corresponding with 
 the more important characteristic differences between the 
 several subdivisions of the family; thus within the same 
 section of the genus Onthophagus, there are species which 
 have a single horn and others which have two. 
 
 In almost all cases the horns are remarkable from their 
 excessive variability; so that a graduated series can be 
 formed from the most highly developed males to others so 
 degenerate that they can barely be distinguished from the 
 females. Mr. Walsh* found that in Phanmis carnifex the 
 horns were thrice as long in some males as in others. Mr. 
 Bates, after examining above a hundred males of Ontho- 
 phagus rangifer (fig. 20), thought that he had at last dis- 
 covered a species in which the horns did not vary; but 
 further research proved the contrary. 
 
 The extraordinary size of the horns and their widely dif- 
 ferent structure in closely-allied forms indicate that they 
 have been formed for some purpose; but their excessive 
 variability in the males of the same species leads to the 
 inference that this purpose cannot be of a definite nature. 
 The horns do not show marks of friction, as if used for any 
 ordinary work. Some authors suppose f that as the males 
 wander about much more than the females, they require 
 horns as a defense against their enemies; but as the horns 
 are often blunt, they do not seem well adapted for defense. 
 The most obvious conjecture is that they are used by the 
 males for fighting together; but the males have never been 
 observed to fight; nor could Mr. Bates, after a careful 
 examination of numerous species, find any sufficient evi- 
 dence, in their mutilated or broken condition, of their 
 having been thus used. If the males had been habitual 
 fighters, the size of their bodies would probably have been 
 increased through sexual selection, so as to have exceeded 
 that of the females; but Mr. Bates, after comparing the 
 
 * " Proc. Entomolog, Soc. of Philadelphia," 1864, p. 228. 
 fKirby and Spence, "Introduct. Entomolog.," vol. iii, p. 300.
 
 INSECTS. 337 
 
 two sexes in above a hundred species of the Copridae, did 
 not find any marked difference in this respect among well- 
 developed individuals. In Lethrus, moreover, a beetle 
 belonging to the same great division of the Lamellicorns, 
 the males are known to fight, but are not provided with 
 horns, though their mandibles are much larger than those of 
 the female. 
 
 The conclusion that the horns have been acquired as 
 ornaments is that which best agrees with the fact of their 
 having been so immensely, yet not fixedly, developed as 
 shown by their extreme variability in the same species, and 
 by their extreme diversity in closely-allied species. This 
 
 Fig. 21. Pig. 22. 
 
 Fig. 21. Onitis furcifer, male viewed from beneath. 
 
 Fig. 22. Left-hand figure, male of Onitis furcifer, viewed laterally. Right- 
 hand figure, female, a. Rudiment of cephalio horn. b. Trace of 
 thoracic horn or crest. 
 
 hereafter find with many animals standing much higher in 
 the scale, namely fishes, amphibians, reptiles and birds, 
 that various kinds of crests, knobs, horns and combs have 
 been developed apparently for this sole purpose. 
 
 The males of Onitis furcifer (fig. 21), and of some other 
 species of the genus are furnished with singular projections 
 on their anterior femora, and with a great fork or pair of 
 horns on the lower surface of the thorax. Judging from 
 other insects, these may aid the male in clinging to the 
 female. Although the males have not even a trace of a horn 
 on the upper surface of the body, yet the females plainly ex- 
 hibit a rudiment of a single horn on the head (fig. 22, a) and 
 of a crest (b) on the thorax. That the slight thoracic crest 
 in the female is a rudiment of a projection proper to the male, 
 
 though entirely absent in the male of this particular species, 
 is clear; for the female of Bu ' 
 
 Bubas bison (a genus which
 
 338 THE DESCENT OF MAN. 
 
 comes next to Onitis) has a similar slight crest on the 
 thorax, and the male bears a great projection in the same 
 situation. So, again, there can hardly be a doubt that the 
 little point (a) on the head of the female Onitis furcifer, 
 as well as on the head of the females of two or three allied 
 species, is a rudimentary representative of the cephalic 
 horn, which is common to the males of so many Lamelli- 
 corn beetles, as in Phaneeus (fig. 18). 
 
 The old belief that rudiments have been created to com- 
 plete the scheme of nature is here so far from holding 
 good, that we have a complete inversion of the ordinary 
 state of things in the family. We may reasonably suspect 
 that the males originally bore horns and transferred them 
 to the females in a rudimentary condition, as in so many 
 other Lamellicorns. Why the males subsequently lost their 
 horns, we know not; but this may have been caused through 
 
 Fig. 23. Bledius taurus, magnified. Left-hand figure, male; right-hand figure, 
 female. 
 
 the principle of compensation, owing to the development of 
 the large horns and projections on the lower surface; and 
 as these are confined to the males, the rudiments of the 
 upper horns on the females would not have been thus 
 obliterated. 
 
 The cases hitherto given refer to the Lamellicorns, but 
 the males of some few other beetles, belonging to two 
 widely distinct groups, namely, the Curculionidae and 
 Staphylinidae, are furnished with horns in the former on 
 the lower surface of the body,* in the latter on the upper 
 surface of the head and thorax. In the Staphylinidge, the 
 horns of the males are extraordinarily variable in the same 
 species, just as we have seen with the Lamellicorns. In 
 Siagouium we have a case of dimorphism, for the males 
 can be divided into two sects, differing greatly in the size 
 of their bodies and in the development of their horns, with- 
 out intermediate gradations. In a species of Bledius (fig. 
 23), also belonging to the Staphylinidas, Prof. Wcstwood 
 *Kirby and Spence, " Introduct. Entomolog.," vol. iii, p. 329.
 
 INSECTS. 339 
 
 states that, ee male specimens can be found in the same 
 locality in which the central horn of the thorax is very 
 large, but the horns of the head quite rudimental ; and 
 others, in which the thoracic horn is much shorter, while 
 the protuberances on the head are long."* Here we appar- 
 ently have a case of compensation, which throws light on 
 that just given, of the supposed loss of the upper horns by 
 the males of Onitis. 
 
 Law of Battle. Some male beetles, which seem ill-fitted 
 for fighting, nevertheless engage in conflicts for the posses- 
 sion of the females. Mr. Wallace f saw two males of 
 LeptorhyncJms angustatus, a linear beetle with a much 
 elongated rostrum, " fighting for a female, who stood close 
 by busy at her boring. They pushed at each otlter with 
 their rostra, and clawed and thumped, apparently in the 
 greatest rage." The smaller male, however, " soon ran 
 away, acknowledging himself vanquished." In some few 
 cases male beetles are well adapted for fighting, by possess- 
 ing great toothed mandibles, much larger than those of the 
 females. This is the case with the common stag-beetle 
 (Lucanus cervus), the males of which emerge from the 
 pupal state about a week before the other sex, so that 
 several may often be seen pursuing the same female. At 
 this season they engage in fierce conflicts. When Mr. A. 
 H. Davis J inclosed two males with one female in a Box 
 the larger male severely pinched the smaller one until he 
 resigned his pretensions. A friend informs me that when a 
 boy he often put the males together to see them fight, and 
 he noticed that they were much bolder and fiercer than the 
 females, as with the higher animals. The males would 
 seize hold of his finger if held in front of them, but not so 
 the females, although they have stronger jaws. The males 
 of many of the Lucanidae, as well as of the above-men- 
 
 * "Modern Classification of Insects," vol. i, p. 172; Siagonium, p. 
 172. In the British Museum I noticed one male specimen of Siago- 
 nium in an intermediate condition, so that the dimorphism is not 
 strict. 
 
 f'The Malay Archipelago," vol. ii, 1869, p. 276. Riley, Sixth 
 "Report on Insects of Missouri," 1874, p. 115. 
 
 J " Entomological Magazine," vol. i, 1833, p. 82. See also on the 
 conflicts of this species, Kirby and Spence, ibid., vol. iii, p. 314; and 
 Westwood, ibid., vol. i, p. 187.
 
 340 THE DESCENT OF MAN. 
 
 tioned Leptorhynchus, are larger and more powerful insects 
 than the females. The two sexes of Letlirus cepJialotes 
 (one of the Lamellicorns) inhabit the same burrow; and 
 the male has larger mandibles than the female. If, during 
 the breeding season, a strange male attempts to enter the 
 burrow he is attacked; the female does not remain passive, 
 but closes the mouth of the burrow, and encourages her 
 mate by continually pushing him on from behind; and the 
 battle lasts until the aggressor is killed or runs away. * The 
 two sexes of another Lamellicorn beetle, the Ateuchus 
 cicatricosus, live in pairs, and seem much attached to each 
 other; the male excites the females to roll the balls of dung 
 in which the ova are deposited; and if she is removed he 
 becomes much agitated. If the male is removed the 
 female ceases all work, and, as M. Brulerie f believes, would 
 remain on the same spot until she died. 
 
 The great mandibles of the male Lucanidae are extremely 
 variable both in size and structure, and in this respect 
 resemble the horns on the head and thorax of many male 
 Lamellicorns and Staphylinidae. A perfect series can be 
 formed from the best-provided to the worst-provided or 
 degenerate males. Although the mandibles of the common 
 stag-beetle, and probably of many other species, are used as 
 efficient weapons for fighting, it is doubtful whether their 
 great size can thus be accounted for. We have seen that they 
 are used by the Lucanus elaphus of North America for 
 seizing the female. As they are so conspicuous and so 
 elegantly branched, and as owing to their great length 
 they are not well adapted for pinching, the suspicion has 
 crossed my mind that they may in addition serve as an 
 ornament, like the horns on the head and thorax of the 
 various species above described. The male Cliiasognathus 
 Grantii of S. Chili a splendid beetle belonging to the 
 same family has enormously developed mandibles (fig. 24) ; 
 he is bold and pugnacious; when threatened he faces round, 
 opens his great jaws, and at the same time stridulates 
 loudly. But the mandibles were not strong enough to pinch, 
 my finger so as to cause acttial pain. 
 
 * Quoted from Fischer, in "Diet. Class. d'Hist. Nat.," torn, x, p. 
 324. 
 
 t " Ann. Soc. Entomolog. France," 1866, as quoted in "Journal of 
 Travel," by A. Murray, 1868, p. 135.
 
 INSECTS. 
 
 341 
 
 Sexual selection, which implies the possession of con- 
 siderable perceptive powers and of strong passions, seems to 
 have been more effective with the 
 Lamellicorns than with any other 
 family of beetles. "With some species 
 the males are provided with weapons ^VL jiy^ 
 
 for fighting; some live in pairs and \ Vt jjj y 
 
 show mutual affection; many have * *- ^ ' 
 
 the power of stridulating when ex- 
 cited; many are furnished with the 
 most extraordinary horns, apparently 
 for the sake of ornament; and some, 
 which are diurnal in their habits, are 
 gorgeously colored. Lastly, several 
 of the largest beetles in the world 
 belong to this family, which was 
 placed by Linnaeus and Fabricius at 
 the head of the order.* 
 
 Stridulating Organs. Beetles be- 
 longing to many and widely distinct 
 families possess these organs. The 
 sound thus produced can sometimes 
 be heard at the distance of several 
 feet or even yards, f but it is not r 
 comparable with that made by the 9" 
 Orthoptera. The rasp generally con- 
 sists of a narrow, slightly raised sur- 
 face, crossed by very fine, parallel 
 ribs, sometimes so fine as to cause 
 iridescent colors, and having a very 
 elegant appearance under the micro- 
 scope. In some cases, as with Ty- 
 phceus, minute, bristly or scale-like 
 prominences, with which the whole 
 surrounding surface is covered in 
 approximately parallel lines, could 
 be traced passing into the ribs of the Fig.. 24. ctnasognathus Gran. 
 
 rasYi Thp frnrnaifinn takpa nlarv* tii, reduced. Upperfigure, 
 rafap. xne transition IdKes place male; lower figure, female. 
 
 * Westwood, " Modern Class.," vol. i, p. 184. 
 fWollaston. "On Certain Musical Curculionidae," "Annals and 
 Mag. of Nat. Hist.," vol. vi, 1860, p. 14.
 
 342 
 
 THE DESCEni OF MAN. 
 
 by their becoming confluent and straight, and at the 
 same time more prominent and smooth. A hard ridge 
 on an adjoining part of the body serves as the scraper 
 for the rasp, but this scraper in some cases has been spe- 
 cially modified for the purpose. It is rapidly moved across 
 the rasp, or conversely the rasp across the scraper. 
 
 Pig. 25. Necrophorus (from Landois). r. The two rasps. Left-hand 
 figure, part of the rasp highly magnified. 
 
 These organs are situated in widely different positions. 
 In the carrion - beetles (Necrophorus) two parallel rasps 
 (r, fig. 25) stand on the dorsal surface of the fifth abdomi- 
 nal segment, each rasp* consisting of 126 to 140 fine ribs. 
 These ribs are scraped against the posterior margins of the 
 elytra, a small portion of which projects beyond the gen- 
 eral outline. In many Crioceridae, and in Clytlira 4=-punc- 
 tata (one of the Chrysomelidae), and in some Tenebrionidse, 
 etc.,f the rasp is seated on the dorsal apex of the abdomen, 
 on the pygidium or pro-pygidium, and is scraped in the 
 same manner by the elytra. In Heterocerus, which belongs 
 to another family, the rasps are placed on the sides of the 
 first abdominal segment and are scraped by ridges on the 
 
 * Landois, " Zeitschrift fur wiss. Zoolog.," B. xvii, 1867, s. 127. 
 f I am greatly indebted to Mr. Q. R. Crotch for having sent me 
 
 families and to others, as well as for valuable information. He be- 
 lieves that the power of stridulation in the Clythra has not been pre- 
 viously observed. I am also much indebted to Mr. E. W. Janson, 
 for information and specimens. I may add that my son, Mr. F. 
 Darwin, finds that Dermestes murimus stridulates, but he searched 
 in vain for the apparatus. Scolytus has lately been described by Dr. 
 Chapman as a stridulator, in the " Entomologist's Monthly Maga- 
 zine," vol. vi, p, 180.
 
 INSECTS. 
 
 343 
 
 femora.* In certain Curculionidge and Carabidaef the 
 parts are completely reversed in position, for the rasps are 
 seated on the interior surface of the elytra, near their 
 apices, or along their .outer margins, and the edges of the 
 abdominal segments serve as the scrapers. In Pelobius 
 Hermanni (one of Dytiscidae or water-beetles) a strong 
 ridge runs parallel and near to the sutural margin of the 
 elytra and is crossed by ribs, coarse in the middle part, but 
 becoming gradually finer at both ends, especially at the 
 upper end; when this insect is held under water or in the 
 air a stridulating noise is produced by the 
 extreme horny margin of the abdomen being 
 scraped against the rasps. In a great num- 
 ber of long-horned beetles (Longicornia) the 
 organs are situated quite otherwise, the rasp 
 being on the meso-thorax, which is rubbed 
 against the pro-thorax. Landois counted 238 
 very fine ribs on the rasp of Cerambyx heros. 
 Many Lamellicorns have the power of 
 stridulating, and the organs differ greatly in 
 position. Some species stridulate very 
 loudly, so that when Mr. F. Smith caught a 
 Trox sabulosus, a gamekeeper who stood by 
 thought he had caught a mouse; but I 
 failed to discover the proper organs in this Fi 
 beetle. In Geotrupes and Typhceus a narrow 
 ridge runs obliquely across (r, fig. 26) the coxa 
 of each hind leg (having in G. stercorarius 84 r. i . 
 ribs), which is scraped by a specially project- i. F S: '' Tlbm> 
 ing part of one of the abdominal segments. 
 In the nearly allied Oopris lunaris an excessively narrow 
 fine rasp runs along the sutural margin of the elytra with 
 another short rasp near the basal outer margin; but in 
 some other Coprini the rasp is seated, according to 
 
 * Schiodte, translated in " Annals and Mag. of Nat. Hist.," vol. xx, 
 1867, p. 37. 
 
 fWestring has described (Kroyer, "Naturhist. Tidskrift," B. ii, 
 1848-1849, p. 334) the stridulating organs in these two, as well as in 
 other families. In the Carabidse I have examined Elaphrus uligi- 
 nosus and BletMsa multipunctata, sent to me by Mr. Crotch. In 
 Blethisa fhe transverse ridges on the furrowed border of the abdom- 
 inal segment do not, as far as I could judge, come into play in scrap- 
 ing the rasps on the elytra. 
 
 Hind leg 
 of Geotrupes 
 stercorarius. 
 From Landois 
 r. Rasp. c. Coxa.
 
 344 THE DESCENT OF MAN. 
 
 Leconte,* on the dorsal surface of the abdomen. In 
 Oryctes it is seated on the propygidium; and, according 
 to the same entomologist, in some other Dynastiui on the 
 under surface of the elytra. Lastly, "\Vestring states that 
 in OmalopUa brunnea the rasp is placed on the pro-sternum 
 and the scraper on the meta-sternum, the parts thus occu- 
 pying the under surf ace -of the body instead of the upper 
 surface, as in the Longicoms. 
 
 We thus see that in the different coleopterous families 
 the stridulating organs are wonderfully, diversified in 
 position, but not much in structure. Within the same 
 family some species are provided with these organs, and 
 others are destitute of them. This diversity is intelligible, 
 if we suppose that originally various beetles made a shuf- 
 fling or hissing noise by the rubbing together of any hard 
 and rough parts of their bodies, which happened to be in 
 contact; and that from the noise thus produced being in 
 some way useful, the rough surfaces were gradually devel- 
 oped into regular stridulatiug organs. Some beetles as they 
 move now produce, either intentionally or unintentionally, 
 a shuffling noise without possessing any proper organs for 
 the purpose. Mr. Wallace informs me that the Eucliirus 
 longimanus (a Lamellicorn, with the anterior legs wonder- 
 fully elongated in the male) " makes, while moving, a low 
 hissing sound by the protrusion and contraction of the 
 abdomen ; and when seized it produces a grating sound 
 by rubbing its hind legs against the edges of the elytra." 
 The hissing sound is clearly due to a narrow rasp running 
 along the sutural margin of each elytron; and I could like- 
 wise make the grating sound by nibbing the shagreened sur- 
 face of the femur against the granulated margin of the cor- 
 responding elytron; but I could not here detect any proper 
 rasp; nor is it likely that I could have overlooked it in so 
 large an insect. After examining Cychrus, and reading 
 what Westring has written about this beetle, it seems very 
 doubtful whether it possesses any true rasp, though it has 
 the power of emitting a sound. 
 
 From the analogy of the Orthoptera and Homoptera, I 
 expected to find the stridulating organs in the Colpeotera 
 differing according to sex; but Landois, who has carefully 
 
 * I am indebted to Mr. Walsh, of Illinois, for having sent me ex- 
 tracts from Leconte's " Introduction to Entomology," pp. 101, 143.
 
 INSECTS. 345 
 
 examined several species, observed no snch difference; nor 
 did Westring; nor did Mr. Gr. R. Crotch in preparing the 
 many specimens winch he had the kindness to send me. 
 Any difference in these organs, if slight, would, however, 
 be difficult to detect, on account of their great variability. 
 Thus, in the first pair of specimens of Necrophorus 
 humator and of PeloMus which I examined, the rasp 
 was considerably larger in the male than in the female; 
 but not so with succeeding specimens. In Geotrupes 
 stercorarius the rasp appeared to me thicker, opaquer 
 and more prominent in three males than in the same 
 number of females ; in order, therefore, to discover 
 whether the sexes differed in their power of stridulat- 
 ing, my son, Mr. F. Darwin, collected fifty-seven living 
 specimens, which he separated into two lots, according as 
 they made a greater or lesser noise, when held in the same 
 manner. He then examined all these specimens and found 
 that the males were very nearly in the same proportion 
 to the females in both the lots". Mr. F. Smith has kept 
 alive numerous specimens of Monoynchus pseudacori (Cur- 
 culionida?), and is convinced that both sexes stridulate, 
 and apparently in an equal degree. 
 
 Nevertheless, the power of stridulating is certainly a 
 sexual character in some few Coleoptera. Mr. Crotch dis- 
 covered that the males alone of two species of Heliopathes 
 (Tenebrionidae) possess stridulating organs. I examined 
 five males of H. gibbus, and in all these there was a well- 
 developed rasp, partially divided into two, on the dorsal 
 surface of the terminal abdominal segment; while in the 
 same number of females there was not even a rudiment of 
 the rasp, the membrane of this segment being transparent 
 and much thinner than in the male. In H. cribratostriatus 
 the male has a similar rasp, excepting that it is not par- 
 tially divided into two portions, and the female is com- 
 pletely destitute of this organ; the male in addition has on 
 the apical margins of the elytra, on each side of the suture, 
 three or four short longitudinal ridges, which are crossed 
 by extremely fine ribs, parallel to and resembling those on 
 the abdominal rasp; whether these ridges serve as an inde- 
 pendent rasp or as a scraper for the abdominal rasp, I could 
 not decid"e ; the female exhibits no trace of this latter 
 structure. 
 
 Again, in three species of the Lamellicorn genus Oryc-
 
 346 THE DESCENT OF MAN. 
 
 tes, we have a nearly parallel case. In the females of 0. 
 gryplius and nasicornis the ribs on the rasp of the pro- 
 pygidium are less continuous and less distinct than in the 
 males; but the chief difference is that the whole upper sur- 
 face of this segment, when held in the proper light, is seen 
 to be clothed with hairs, which are absent or are repre- 
 sented by excessively fine down in the males. It should be 
 noticed that in all Coleoptera the effective part of the rasp 
 is destitute of hairs. In 0. senegalensis the difference be- 
 tween the sexes is more strongly marked, and this is best 
 Been when the proper abdominal segment is cleaned and 
 viewed as a transparent object. In the female the whole 
 surface is covered with little separate crests bearing spines; 
 while in the male these crests, in proceeding toward the 
 apex, become more and more confluent, regular and naked; 
 so that three-fourths of the segment is covered with ex- 
 tremely fine parallel ribs, which are quite absent in the 
 female. In the females, however, of all three species of 
 Oryctes, a slight grating or stridulating sound is produced 
 when the abdomen of a softened specimen is pushed back- 
 ward and forward. 
 
 In the case of the Heliopathes and Oryctes there can 
 hardly be a doubt that the males stridulate in order to call 
 or to excite the females; but with most beetles the stridu- 
 lation apparently serves both sexes as a mutual call. 
 Beetles stridulate under various emotions, in the same 
 manner as birds use their voices for many purposes besides 
 singing to their mates. The great Chiasognathus stridu- 
 lates in anger or defiance; many species do the same from 
 distress or fear, if held so that they cannot escape ; by 
 striking the hollow stems of trees in the Canary Islands, 
 Messrs. Wollaston and Crotch were able to discover the 
 presence of beetles belonging to the genus Acalles by their 
 stridulation. Lastly, the male Ateuchus stridulates to en- 
 courage the female in her work, and from distress when she 
 is removed.* Some naturalists believe that beetles make 
 this noise to frighten away their enemies; but I cannot 
 think that a quadruped or bird, able to devour a large 
 beetle, would be frightened by so slight a sound. The 
 belief that the stridulation serves as a sexual call is sup- 
 
 M. P. de la Brulerie, as quoted in " Journal of Travel," A. Mur- 
 raj, vol. I, 1868, p. 185.
 
 INSECTS. 347 
 
 ported by the fact that death-ticks (Anolium tessellatum) 
 are well known to answer each other's ticking, and, as I 
 have myself observed, a tapping noise artificially made. 
 Mr. Doubleday also informs me that he has sometimes ob- 
 served a female ticking,* and in an hour or two afterward 
 has found her united with a male, and on one occasion sur- 
 rounded by several males. Finally, it is probable that the 
 two sexes of many kinds of beetles were at first enabled to 
 find each other by the slight shuffling noise produced by 
 the rubbing together of the adjoining hard parts of their 
 bodies; and that as those males or females which made the 
 greatest noise succeeded best in finding partners, rugosities 
 on various parts of their bodies were gradually developed 
 by means of sexual selection into true stridulating organs. 
 
 * According to Mr. Doubleday, "the noise is produced by the 
 insect raising itself on its legs as high as it can, and then striking its 
 thorax five or six times in rapid succession against the substance 
 upon which it is sitting." For references on this subject see Landois, 
 " Zeitschrift f iir wissen. Zoolog.," B. xvii, s. 131. Olivier says (as 
 quoted by Kirby and Spence, " Introduct.," vol. ii, p. 395) that the 
 female of Pimelia striata produces a rather loud sound by striking 
 her abdomen against any hard substance, " and that the male, obedi- 
 ent to this call, soon attends her, and they pair."
 
 348 THE DESCENT OF MAN. 
 
 CHAPTER XI. 
 
 INSECTS, continued. OEDEE LEPIDOPTERA. 
 (BUTTERFLIES AND MOTHS.) 
 
 Courtship of butterflies Battles Ticking noise Colors common to 
 both sexes, or more brilliant in the males Examples Not due 
 to the direct action of the conditions of life Colors adapted for 
 protection Colors of moths Display Perceptive powers of the 
 Lepidoptera Variability Causes of the difference in color 
 between the males and females Mimicry, female butterflies more 
 brilliantly colored than the males Bright colors of caterpillars 
 Summary and concluding remarks on the secondary sexual char- 
 acters of insects Birds and insects compared. 
 
 IN this great order the most interesting points for us are 
 the differences in color between the sexes of the same 
 species, and between the distinct species of the same genus. 
 Nearly the whole of the following chapter will be devoted 
 to this subject; but I will first make a few remarks on one 
 or two other points. Several males may often be seen pur- 
 suing and crowding round the same female. Their court- 
 ship appears to be a prolonged affair, for I have frequently 
 watched one or more males pirouetting round a female 
 until I was tired, without seeing the end of the courtship. 
 Mr. A. G. Butler also informs me that he has several times 
 watched a male courting a female for a full quarter of an 
 hour; but she pertinaciously refused him, and at last set- 
 tled on the ground and closed her wings, so as to escape 
 from his addresses. 
 
 Although butterflies are weak and fragile creatures, they 
 are pugnacious, and an Emperor butterfly* has been capt- 
 ured with the tips of its wings broken from a conflict with 
 another male. Mr. Collingwood, in speaking of the fre- 
 quent battles between the butterflies of Borneo, says: " They 
 
 * Apatura Iris: "The Entomologist's Weekly Intelligence," 1859, 
 p. 189. For the Bornean Butterflies, see C. Collingwood, " Ramble* 
 of a Naturalist." 1868, p. 183.
 
 INSECTS. 349 
 
 whirl round each other with the greatest rapidity, and 
 appear to be incited by the greatest ferocity." 
 
 The Ageronia feionia makes a noise like that produced 
 by a toothed wheel passing under a spring catch, and 
 which can be Jieard at the distance of several yards; I 
 noticed this sound at Rio de Janeiro, only when two of 
 these butterflies were chasing each other in an irregular 
 course, so that it is probably made during the courtship of 
 the sexes.* 
 
 Some moths also produce sounds; for instance, the males 
 of Thecophora fovea. On two occasions Mr. P. Buchanan 
 White f heard a sharp quick noise made by the male of 
 Hylophila prasinana, and which he believes to be produced, 
 as in Cicada, by an elastic membrane, furnished with a 
 muscle. He quotes, also, Guenee, that Setina produces a 
 sound like the ticking of a watch, apparently by the aid of 
 " two large tympaniform vesicles, situated in the pectoral 
 region;" and these "are much more developed in the male 
 than in the female." Hence the sound-producing organs in 
 the Lepidoptera appear to stand in some relation with the 
 sexual functions. I have not alluded to the well-known 
 noise made by the Death's Head Sphinx, for it is generally 
 heard soon after the moth has emerged from its cocoon. 
 
 Giard has always observed that the musky odor, which 
 is emitted by two species of Sphinx moths, is peculiar to 
 the males; \ and in the higher classes we shall meet with 
 many instances of the males alone being odoriferous. 
 
 Every one must have admired the extreme beauty of 
 many butterflies and of some moths; and it may be asked, 
 are their colors and diversified patterns the result of the 
 direct action of the physical conditions to which these 
 insects have been exposed, without any benefit being thus 
 derived? Or have successive variations been accumulated 
 and determined as a protection, or for some unknown pur- 
 pose, or that one sex may be attractive to the other? And, 
 
 * See my "Journal of Researches," 1845, p. 33. Mr. Doubleday 
 Las detected ("Proc. Ent. Soc.," March 3, 1845, p. 123) a peculiar 
 membranous sac at the base of the front wings, which is probably 
 connected-with the production of the sound. For the case of Theco- 
 phora, see "Zoological Record," 1869, p. 401. For Mr. Buchanan 
 White's observations, " The Scottish Naturalist," July, 1872, p. 214. 
 
 f "The Scottish Naturalist," July, 1872, p. 213. 
 
 t " Zoological Record," 1869, p. 347.
 
 350 THE DESCENT OF MAN. 
 
 again, what is the^meaning of the colors being widely dif- 
 ferent in the males and females of certain species, and 
 alike in the two sexes of other species of the same genus? 
 Before attempting to answer these questions a body of 
 facts must be given. 
 
 With our beautiful English butterflies, the admiral, pea- 
 cock, and painted lady (Vanessae), as well as many others, 
 the sexes are alike. This is also the case with the magnifi- 
 cent Heliconidae, and most of the Danaidae in the tropics. 
 But in certain other tropical groups, and in some of our 
 English butterflies, as the purple emperor, orange-tip, etc. 
 (Apatura Iris and Anthocharis cardamines), the sexes 
 differ either greatly or slightly in color. No language suf- 
 fices to describe the splendor of the males of some tropical 
 species. Even within the same genus we often find species 
 presenting extraordinary differences between the sexes, 
 while others have their sexes closely alike. Thus in the 
 South American genus Epicalia, Mr. Bates, to whom I am 
 indebted for most of the following facts, and for looking 
 over this whole discussion, Informs me that he knows twelve 
 species, the two sexes of which haunt the same stations 
 (and this is not always the case with butterflies), and 
 which, therefore, cannot have been differently affected by 
 external conditions.* In nine of these twelve species the 
 males rank among the most brilliant of all butterflies, and 
 differ so greatly from the comparatively plain females that 
 they were formerly placed in distinct genera. The females 
 of these nine species resemble each other in their general 
 type of coloration; and they likewise resemble both sexes 
 of the species in several allied genera found in various parts 
 of the world. Hence we may infer that these nine species, 
 and probably all the others of the genus, are descended 
 from an ancestral form which was colored in nearly the 
 same manner. In the tenth species the female still retains 
 the same general coloring, but the male resembles her, so 
 that he is colored in a much less gaudy and contrasted 
 manner than the males of the previous species. In the 
 eleventh and twelfth species the females depart from the 
 usual type, for they are gayly decorated almost like the 
 
 * See also Mr, Bates' paper in " Proc. Ent. Soc. of Philadelphia," 
 1865, p. 206. Also Mr, Wallace on the same subject, in regard to 
 Diadema, in "Transact. Entomolog. Soc. of London," 1869, p. 278.
 
 INSECTS. 351 
 
 males, but in a somewhat less degree. Hence in these two 
 latter species the bright colors of the males seem to have 
 been transferred to the females; while in the tenth species 
 the male has either retained or recovered the plain colors of 
 the female, as well as of the parent-form of the genus. The 
 sexes in these three cases have thus been rendered nearly 
 alike, though in an opposite manner. In the allied genus 
 Eubagis, both sexes of some of the species are plain-colored 
 and nearly alike; while the greater number of the males are 
 decorated with beautiful metallic tints in a diversified 
 manner, and differ much from their females. The females 
 throughout the genus retain the same general style of 
 coloring, so that they resemble one another much more 
 closely than they resemble their oAvn males. 
 
 In the genus Papilio all the species of the ^Eneas group 
 are remarkable for their conspicuous and strongly con- 
 trasted colors, and they illustrate the frequent tendency to 
 gradation in the amount of difference between the sexes. 
 In a few species, for instance in P. ascanius, the males and 
 females are alike; in others the males' are either a little 
 brighter, or very much more superb than the females. The 
 genus Junonia, allied to our Vanessae, offers a nearly 
 parallel case, for although the sexes of most of the species 
 resemble each other, and are destitute of rich colors, yet in 
 certain species, as in /. cenone, the male is rather more 
 bright - colored than the female, and in a few (for 
 instance J. andremiaja) the male is so different from the 
 female that he might be mistaken for an entirely distinct 
 species. 
 
 Another striking case was pointed out to me in the Brit- 
 ish Museum by Mr. A. Butler, namely, one of the tropical 
 American Theclae, in which both sexes are nearly alike and 
 wonderfully splendid; in another species the male is colored 
 in a similarly gorgeous manner, while the whole upper 
 surface of the female is of a dull uniform brown. Our 
 common little English blue butterflies of the genus Lycaena 
 illustrate the various differences iu color between the sexes 
 almost as well, though not in so striking a manner, as the 
 above exotic genera. In Lyccena agestis both sexes have 
 wings of a brown color, bordered with small ocellated 
 orange spots and are thus alike. In L. cegon the wings of 
 the male are of a fine blue bordered with black, while 
 those of the female are brown with a similar border closely
 
 352 THE DESCENT OF MAN. 
 
 resembling the wings of L. agestis. Lastly, in L. arion 
 both sexes are of a blue color and are very like, though in 
 the female the edges of the wings are rather duskier with 
 the black spots plainer; and in a bright-blue Indian species 
 both sexes are still morte alike. 
 
 I have given the foregoing details in order to show, in 
 the first place, that when the sexes of butterflies differ the 
 male as a general rule is the more beautiful and departs 
 more from the usual type of coloring of the group to which 
 the species belongs. Hence in most groups the females of 
 the several species resemble each other much more closely 
 than do the males. In some cases, however, to which I 
 shall hereafter allude, the females are colored more splen- 
 didly than the males. In the second place, these details 
 have been given to bring clearly before the mind that 
 within the same genus the two sexes frequently present 
 every gradation from no difference in color to so great a 
 difference that it was long before the two were placed by 
 entomologists in the same genus. In the third place, we 
 have seen that when the sexes nearly resemble each other 
 this appears due either to the male having transferred his 
 colors to the female, or to the male having retained or per- 
 haps recovered the primordial colors of the group. It also 
 deserves notice that in those groups in which the sexes 
 differ the females usually somewhat resemble the males, 
 so that when the males are beautiful to an extraordinary 
 degree the females almost invariably exhibit some degree 
 of beauty. From the many cases of gradation in the 
 amount of difference between the sexes, and from the prev- 
 alence of the same general type of coloration throughout 
 the whole of the same group, we may conclude that the 
 causes have generally been the same which have determined 
 the brilliant coloring of the males alone of some species, 
 and of both sexes of other species. 
 
 As so many gorgeous butterflies inhabit the tropics it 
 has often been supposed that they owe their colors to the 
 great heat and moisture of these zones; but Mr. Bates* has 
 shown by the comparison of various closely-allied groups of 
 insects from the temperate and tropical regions that this 
 view cannot be maintained; and the evidence becomes con- 
 clusive when brilliantly colored males and plain colored 
 
 * "The Naturalist cm the Amazons," vol. i, 1863, p. 19.
 
 INSECTS. 353 
 
 females of the same species inhabit the same district, feed 
 on the same food and follow exactly the same habits of 
 life. Even when the sexes resemble each other we can 
 hardly believe that their brilliant and beautifully arranged 
 colors are the purposeless result of the nature of the tissues 
 ani of the action of the surrounding conditions. 
 
 "With animals of all kinds, whenever color has been 
 modified for some special purpose, -this has been, as far as 
 we can judge, either for direct or indirect protection, or as 
 an attraction between the sexes. With many species of 
 butterflies the upper surfaces of the wings are obscure; and 
 this in all probability leads to their escaping observation 
 and danger. But butterflies would be particularly liable 
 to be attacked by their enemies when at rest; and most 
 kinds while resting raise their wings vertically over their 
 backs, so that the lower surface alone is exposed to view. 
 Hence it is this side which is often colored so as to imitate 
 the objects on which these insects commonly rest. Dr. 
 Eossler, I believe, first noticed the similarity of the closed 
 wings of certain Vanessae and other butterflies to the bark 
 of trees. Many analogous and striking facts could be given. 
 The most interesting one is that recorded by Mr. Wallace* 
 of a common Indian and Sumatran butterfly (Kallima), 
 which disappears like magic when it settles on a bush; for 
 it hides its head and antennas between its closed wings, 
 which, in form, color and veining, cannot be distinguished 
 from a withered leaf with its footstalk. In some other 
 cases the lower surfaces of the wings are brilliantly colored, 
 and yet are protective; thus in Thecla rubi the wings when 
 closed are of an emerald green and resemble the young 
 leaves of the bramble, on which in spring this butterfly 
 may often be seen seated. It is also remarkable that in very 
 many species in which the sexes differ greatly in color on 
 their upper surface, the lower surface is closely similar or 
 identical in both sexes, and serves as a protection, f 
 
 Although the obscure tints both of the upper and under 
 sides of many butterflies no doubt serve to conceal them, yet 
 we cannot extend this view to the brilliant and conspicuous 
 colors on the upper surface of such species as our admiral and 
 
 * See the interesting article in the " Westminster Review," July, 
 1867, p, 10, A wood-cut of the Kallima is given by Mr. Wallace iu 
 "Hardwicke's Science Gossip," Sept., 1867, p. 196. 
 
 | Mr. Q. Fraser, in "Nature," April, 1871, p. 489.
 
 354 THK DESCENT OF MAN. 
 
 peacock Vanessae, our white cabbage-butterflies (Pieris), or 
 the great swallow-tail Papilio which haunts the open fens 
 for these butterflies are thus rendered visible to every living 
 creature. In these species both sexes are alike; but in the 
 common brimstone butterfly (Gonepteryx rliamni], the male 
 is of an intense yellow, while the female is much paler; and 
 in the orange-tip (Anthocharis cardamines) the males alone 
 have their wings tipped with bright orange. Both the 
 males and females in these cases are conspicuous, and it is 
 not credible that their difference in color should stand in 
 any relation to ordinary protection. Prof. Weismann 
 remarks * that the female of one of the Lycasnas expands 
 her brown wings when she settles on the ground, and is 
 then almost invisible; the male, on the other hand, as if 
 aware of the danger incurred from the bright blue of the 
 upper surface of his wings, rests with them closed; and this 
 shows that the blue color cannot be in any way protective. 
 Nevertheless, it is probable that conspicuous colors are 
 indirectly beneficial to many species, as a warning that they 
 are unpalatable. For in certain other cases, beauty has 
 been gained through the imitation of other beautiful 
 species, which inhabit the same district and enjoy an im- 
 munity from attack by being in some way offensive to their 
 enemies; but then we have to account for the beauty of the 
 imitated species. 
 
 As Mr. Walsh has remarked to me, the females of our 
 orange-tip butterfly, above referred to, and of an American 
 species (Anth. genutia) probably show us the primordial 
 colors of the parent-species of the genus; for both sexes of 
 four or five widely-distributed species are colored in nearly 
 the same manner. As in several previous cases, we may 
 here infer that it is the males of Anth. cardamines and 
 genutia which have departed from the usual type of the 
 genus. In the Anth. sara from California, the orange tips 
 to the wings have been partially developed in the female ; 
 but they are paler than in the male, and slightly different 
 in some other respects. In an allied Indian form, the 
 Iphias glaucippe, the orange-tips are fully developed in 
 both sexes. In this Iphias, as pointed out to me by Mr. A. 
 Butler, the under surface of the wings marvelously resem- 
 bles a pale-colored leaf; and in our English orange-tip, the 
 
 * Einfluss der leolirung auf di. Artbildung," 1872, p. 68-
 
 INSECTS. 355 
 
 under surface resembles the flower-head of the wild parsley, 
 on which the butterfly often rests at night.* The same 
 reason which compels us to believe that the lower surfaces 
 have here been colored for the sake of protection, leads us 
 to deny that the wings have been tipped with bright orange 
 for the same purpose, especially when this character is con- 
 fined to the males. 
 
 Most moths rest motionless during the whole or greater 
 part of the day with their wings depressed; and the whole 
 upper surface is often shaded and colored in an admirable 
 manner, as Mr. Wallace has remarked, for escaping detec- 
 tion. The front-wings of the Bombycidae and N"octuidae,f 
 when at rest, generally overlap and conceal the hind wings; 
 so that the latter might be brightly colored without much 
 risk; and they are in fact often thus colored. During 
 flight, moths would often be able to escape from their ene- 
 mies; nevertheless, as the hind wings are then fully exposed 
 to view, their bright colors must generally have been 
 acquired at some little risk. But the following fact shows 
 how cautious we ought to be in drawing conclusions on this 
 head. The common yellow under wings (Triphaena) often 
 fly about during the day or early evening, and are then 
 conspicuous from the color of their hind wings. It would 
 naturally be thought that this would be a source of danger; 
 but Mr. J. Jenner Weir believes that it actually serves 
 them as a means of escape, for birds strike at these brightly 
 colored and fragile surfaces, instead of at the body. For 
 instance, Mr. Weir turned into his aviary a vigorous speci- 
 men of TripJicena pronuba, which was instantly pursued by 
 a robin: but the bird's attention being caught by the col- 
 ored wings, the moth was not captured until after about 
 fifty attempts, and small portions of the wings were repeat- 
 edly broken off. He tried the same experiment in the 
 open air, with a swallow and T. fimbria ; but the large 
 size of this moth probably interfered with its capture. J 
 We are thus reminded of a statement made by Mr. Wal- 
 
 * See the interesting observations by Mr. T. W. Wood, " The 
 
 Student," Sept., 1868, p. 81. 
 
 f Mr. Wallace in " Hardwicke's Science Gossip, " Sept., 1867, p. 193. 
 
 \ See also on this subject, Mr. Weir's paper in " Transact. Ent 
 Soc,," 1869, p. 23.
 
 356 THE DESCENT OF MAN. 
 
 lace,* namely, that in the Brazilian forests and Malayan 
 islands, many common and highly-decorated butterflies 
 are weak flyers, though furnished with a broad expanse of 
 wing; and they "are often captured with pierced and 
 broken wings, as if they had been seized by birds, from 
 which they had escaped; if the wings had been much 
 smaller in proportion to the body, it seems probable that 
 the insect would more frequently have been struck or 
 pierced in a vital part, and thus the increased expanse of 
 the wings may have been indirectly beneficial. " 
 
 Display. The bright colors of many butterflies and of 
 some moths are specially arranged for display, so that they 
 may be readily seen. During the night colors are not vis- 
 ible, and there can be no doubt that the nocturnal moths, 
 taken as a body, are much less gayly decorated than butter- 
 flies, all of which are diurnal in their habits. But the 
 moths of certain families, such as the Zygaenidse, several 
 Sphingidge, Uraniidae, some Arctiidae and Saturniidse, fly 
 about during the day or early evening, and many of these 
 are extremely beautiful, being far brighter-colored than the 
 strictly nocturnal kinds. A few exceptional cases, how- 
 ever, of bright - colored nocturnal species have been 
 recorded. f 
 
 There is evidence of another kind in regard to display. 
 Butterflies, as before remarked, elevate their wings when 
 at rest, but while basking in the sunshine often alternately 
 raise and depress them, thus exposing both surfaces to full 
 view; and although the lower surface is often colored in an 
 obscure manner as a protection, yet in many species it is as 
 highly decorated as the upper surface, and sometimes in a 
 very different manner. In some tropical species the lower 
 surface is even more brilliantly colored than the upper. J 
 In the English fritillaries (Argynnis) the lower surface 
 
 *" Westminster Review," July, 1867, p. 16. 
 
 f For instance, Lithosia; but Prof. Westwood ("Modern Class, of 
 Insects," vol. ii, p. 390) seems surprised at this case. On the relative 
 colors of diurnal and nocturnal Lepidoptera, see ibid., pp. 333, 392; 
 also Harris, "Treatise on the Insects of New England," 1842, p. 315. 
 
 \ Such differences between the upper and lower surfaces of the 
 wings of several species of Papiliomay be seen in the beautiful plates 
 to Mr. Wallace's "Memoir on the Papilionidae of the Malayan 
 Begion," in "Transact. Linn. Soc.," vol. xxv, part i, 1865.
 
 INSECTS. 35? 
 
 alone is ornamented with shining silver. Nevertheless, as 
 a general rule, the upper surface, which is probably more 
 fully exposed, is colored more brightly and diversely than 
 the lower. Hence the lower surface generally affords to 
 entomologists the more useful character for detecting the 
 affinities of the various species. Fritz Miiller informs me 
 that three species of Castnia are found near his house in 
 S. Brazil; of two of them the hind wings are obscure, and 
 are always covered by the front wings when these butter- 
 flies are at rest; but the third species has black hind wings, 
 beautifully spotted with red and white, and these are fully 
 expanded and displayed whenever the butterfly rests. Other 
 such cases could be added. 
 
 If we now turn to the enormous group of moths which, 
 as I hear from Mr. Stainton, do not habitually expose the 
 under surface of their wings to full view, we find this side 
 very rarely colored with a brightness greater than, or even 
 equal to, that of the upper side. Some exceptions to the 
 rule, either real or apparent, must be noticed, as the case of 
 Hypopyra.* Mr. Trimen informs me that in Guenee's 
 great work three moths are figured, in which the under sur- 
 face is much the more brilliant. For instance, in the Aus- 
 tralian Gastrophora the upper surface of the fore wing is 
 pale grayish-ochreous, while the lower surface is magnifi- 
 cently ornamented by an ocellus of cobalt-blue, placed in 
 the midst of a black mark, surrounded by orange-yellow, 
 and this by bluish-white. But the habits of these three 
 moths are unknown; so that no explanation can be given 
 of their unusual style of coloring. Mr. Trimen also 
 informs me that the lower surface of the wings in certain 
 other Geometrae f and quadrifid Noctuae are either more 
 variegated or more brightly-colored than the upper surface; 
 but some of these species have the habit of "holding their 
 wings quite erect over their backs, retaining them in this 
 position for a considerable time/' and thus exposing the 
 under surface to view. Other species, when settled on the 
 ground or herbage, now and then suddenly and slightly lift 
 
 *See Mr. Wormald on this moth; " Proc. Ent. Soc.," March 2, 
 1868. 
 
 f Se also an account of the South American genus Erateina (one 
 of the Geometrae) in "Transact. Ent. Soc.." new series, vol. v, pis 
 xv and xvi.
 
 358 THE DESCENT OF MAN. 
 
 up their wings. Hence the lower surface of the wings 
 being brighter than the upper surface in certain moths is 
 not so anomalotis as it at first appears. The Saturniidaj 
 include some of the most beautiful of all moths., their wings 
 being decorated, as in our British Emperor moth, with fine 
 ocelli; and Mr. T. W. Wood * observes that they resemble 
 butterflies in some of their movements; "for instance, in 
 the gentle waving up and down of the wings as if for dis- 
 play, which is more characteristic of diurnal than of 
 nocturnal Lepidoptera." 
 
 It is a singlar fact that no British moths which are 
 brilliantly colored, and, as far as I can discover, hardly any 
 foreign species, differ much in color according to sex; 
 though this is the case with many brilliant butterflies. The 
 male, however, of one American moth, the Saturnia lo, is 
 described as having its fore wings deep yellow, curiously 
 marked Avith purplish-red spots; while the wings of the 
 female are purple-brown, marked with gray lines, f The 
 British moths which differ sexually in color are all brown, 
 or of various dull yellow tints, or nearly white. In several 
 species the males are much darker than the females, J and 
 these belong to groups which generally fly about during 
 the afternoon. On the other hand, in many genera, as 
 Mr. Stainton informs me, the males have the hind wings 
 whiter than those of the female of which fact Agrotis 
 exclamationis offers a good instance. In the Ghost Moth 
 (Hepialus humuli) the difference is more strongly 
 marked; the males being white and the females yellow 
 
 *"Proc. Ent. Soc. of London," July 6, 1868, p. 27. 
 
 f Harris, "Treatise," etc., edited by Flint, 1862, p 395. 
 
 J For instance, I observe in my son's cabinet that the males are 
 darker than the females in the Lnsiocampa qutrcus, Odonestis pota- 
 toria, Hypogymna dispar, Dasychira pudtbunda and Cycnia mendica. 
 In this latter species the difference in color between the two sexes is 
 strongly marked; and Mr. Wallace informs me that we here have, as 
 lie believes, an instance of protective mimicry confined to one sex, as 
 will hereafter be more fully explained. The white female of the 
 Cycnia resembles the very common Spttosoma mentkrasti, both sexes 
 of which are white; and Mr. Stainton observed that this latter moth 
 was rejected with utter disgust by a whole brood of young turkeys, 
 which were fond of eating other moths; so that if the Cycnia was 
 commonly mistaken by British birds for the Spilosoma, it would es- 
 cape being devoured, and its white, deceptive color would thus be 
 highly beneficial.
 
 INSECTS. 359 
 
 with darker markings.* It is probable that in these 
 cases the males are thus rendered more conspicuous, and 
 more easily seen by the females while flying about in the 
 dusk. 
 
 From the several foregoing facts it is impossible to admit 
 that the brilliant colors of butterflies, and of some few 
 moths, have commonly been acquired for the sake of pro- 
 tection. We have seen that their colors and elegant pat- 
 . terns are arranged and exhibited as if for display. Hence 
 I am led to believe that the females prefer or are most 
 excited by the more brilliant males; for on any other sup- 
 position the males would, as far as we can see, be orna- 
 mented to no purpose. We know that ants and certain 
 Lamellicorn beetles are capable of feeling an attachment 
 for each other, and that ants recognize their fellows after 
 an interval of several months. Heuce there is no abstract 
 improbability in the Lepidoptera, which probably stand 
 nearly or quite as high in the scale as these insects, having 
 sufficient mental capacity to admire bright colors. They 
 certainly discover flowers by color. The humming-bird 
 sphinx may often be seen to swoop down from a distance 
 on a bunch of flowers in the midst of green foliage; and I 
 have been assured by two persons abroad that these moths 
 repeatedly visit flowers painted on the walls of a room and 
 vainly endeavor to insert their proboscis into them. Fritz 
 Miiller informs me that several kinds of butterflies in 
 S. Brazil show an unmistakable preference for certain 
 colors over others. He observed that they very often 
 visited the brilliant red flowers of five or six genera of 
 plants, but never the white or yellow flowering species of 
 the same and other genera growing in the same garden; 
 and I have received other accounts to the same effect. As 
 I hear from Mr. Doubleday, the common white butterfly 
 often flies down to a bit of paper on the ground, no doubt 
 mistaking it for one of its own species. Mr. Collingwoodf 
 
 * It is remarkable that in the Shetland Islands the male of this 
 moth, instead of differing widely from the female, frequently resem- 
 bles her closely in color (see Mr. MacLachlan, " Transact. Ent. Soc.," 
 vol. ii, 1866, p. 459). Mr. G. Fraser suggests ("Nature," April, 
 1871, p. 489) that at the season of the year when the ghost-moth ap- 
 pears in these northern islands, the whiteness of the males would 
 not be needed to render them visible to the females in the twilight 
 night. 
 
 f " Rambles of a Naturalist in the Chinese Seas," 1868, p. 183.
 
 360 THE DESCENT OF MAN. 
 
 in speaking of the difficulty in collecting certain butter- 
 flies in the Malay Archipelago, states that "a dead speci- 
 men pinned upon a conspicuous twig will often arrest an 
 insect of the same species in its headlong flight and bring 
 it down within easy reach of the net, especially if it be of 
 the opposite sex." 
 
 The courtship of butterflies is, as before remarked, a 
 prolonged affair. The males sometimes fight together in 
 rivalry; and many may be seen pursuing or crowding round 
 the same female. Unless, then, the females prefer one 
 male to another the pairing must be left to mere chance, 
 and this does not appear probable. If, on the other hand, 
 the females habitually, or even occasionally, prefer the 
 more beautiful males, the colors of the latter will have been 
 rendered brighter by degrees, and will have been trans- 
 mitted to both sexes or to one sex, according to the law of 
 inheritance which has prevailed. The process of sexual 
 selection will have been much facilitated, if the conclusion 
 can be trusted, arrived at from various kinds of evidence 
 in the supplement to the ninth chapter; namely, that the 
 males of many Lepidoptera, at least in the imago state, 
 greatly exceed the females in number. 
 
 Some facts, however, are opposed to the belief that female 
 butterflies prefer the more beautiful males; thus, as I have 
 been assured by several collectors, fresh females may fre- 
 quently be seen paired with battered, faded, or dingy males; 
 but this is a circumstance which could hardly fail often to 
 follow from the males emerging from their cocoons earlier 
 than the females. With moths of the family of the Bom- 
 bycidae, the sexes pair immediately after assuming the 
 imago state; for they cannot feed, owing to the rudiment- 
 ary condition of their mouths. The females, as several 
 entomologists have remarked to me, lie in an almost torpid 
 state, and appear not to wince the least choice in regard to 
 their partners. This is the case with the common silk-moth 
 (B. mori), as I have been told by some continental and 
 English breeders. Dr. Wallace, who has had great experi- 
 ence in breeding Bonibyx cyntliia, is convinced that the 
 females evince no choice or preference. He has kept above 
 three hundred of these moths together, and has often found 
 the most vigorous females mated with stunted males. The 
 reverse appears to occur seldom; for, as he believes, the 
 more vigorous males pass over the weakly females, and are
 
 INSECTS. 361 
 
 attracted by those endowed with most vitality. Never- 
 theless, the Bombycidse, though obscurely colored, are 
 often beautiful to our eyes from their elegant and mottled 
 shades. 
 
 I have as yet only referred to the species in which the 
 males are brighter colored than the females, and I have 
 attributed their beauty to the females for many generations 
 having chosen and paired with the more attractive males. 
 But converse cases occur, though rarely, in which the 
 females are more brilliant than the males; and here, as I 
 believe, the males have selected the more beautiful females, 
 and have thus slowly added to their beauty. We do not 
 know why in various classes of animals the males of some 
 few species have selected the more beautiful females instead 
 of having gladly accepted any female, as seems to be the 
 general rule in the animal kingdom; but if, contrary to 
 what generally occurs with the Lepidoptera, the females 
 were much more numerous than the males, the latter would 
 be likely to pick out the more beautiful females. Mr. But- 
 ler showed me several species of Callidryas in the British 
 Museum, in some of which the females equaled, and in 
 others greatly surpassed, the males in beauty ; for the 
 females alone have the borders of their wings suffused with 
 crimson and orange and spotted with black. The plainer 
 males of these species closely resemble each other, showing 
 that here the females have been modified; whereas in those 
 cases, where the males are the more ornate, it is these which 
 have been modified, the females remaining closely alike. 
 
 In England we have some analogous cases, though not so 
 marked. The females alone of two species of Thecla have 
 a bright purple or orange patch on their fore wings. In 
 Hipparchia the sexes do not differ much ; but it is the 
 female of H. janira which has a conspicuous light brown 
 patch on her wings; and the females of some of the other 
 species are brighter colored than their males. Again, 
 the females of Colias edusa and Jiyale have "orange or 
 yellow spots on the black marginal border, represented in 
 the males only by thin streaks;" and in Pieris it is the 
 females ,which "are ornamented with black spots on the 
 fo're wings, and these are only partially present in the 
 males." Now the males of many butterflies are known to 
 support the females during their marriage flight; but in 
 the species just named it is the females which support the
 
 362 THE DESCENT OF MAN. 
 
 males; so that the part which the two sexes play is reversed, 
 as is their relative beauty. Throughout the animal king- 
 dom the males commonly take the more active share in 
 wooing, and their beauty seems to have been increased by 
 the females having accepted the more attractive individuals; 
 but with these butterflies the females take the more active 
 part in the final marriage ceremony, so that we may sup- 
 pose that they likewise do so in the wooing; and in this case 
 we can understand how it is that they have been rendered 
 the more beautiful. Mr. Meldola, from whom the fore- 
 going statements have been taken, says in conclusion: 
 " Though I am not convinced of the action of sexual selec- 
 tion in producing the colors of insects, it cannot be denied 
 that these facts are strikingly corroborative of Mr. Darwin's 
 views. * 
 
 As sexual selection primarily depends on variability, a 
 few words must be added on this subject. In respect to 
 color there is no difficulty, for any number of highly variable 
 Lepidoptera could be named. One good instance will suffice. 
 Mr. Bates showed me a whole series of specimens of Papilio 
 sesostris and P. childrence; in the latter the males varied 
 much in the extent of the beautifully enameled green patch 
 on the fore wings, and in the size of the white mark, and 
 of the splendid crimson stripe on the hind wings; so that 
 there was a great contrast among the males between the 
 most and the least gaudy. The male of Papilio sesostris 
 is much less beautiful than of P. childrence; and it like- 
 wise varies a little in the size of the green patch on the 
 fore wings, and in the occasional appearance of the small 
 crimson stripe on the hind wings, borrowed, as it would 
 .seem, from its own female; for the females of this and of 
 many other species in the JEneas group possess this crimson 
 stripe. Hence between the brightest specimens of P. ses- 
 ostris and the dullest of P. childrencB there was but a small 
 interval; and it was evident that as far as mere variability 
 is concerned, there would be no difficulty in permanently 
 increasing the beauty of either species by means of selec- 
 tion. The variability is here almost confined to the male 
 
 * "Nature," April 27, 1871, p. 508. Mr. Meldola quotes Donzel, 
 in "Soc. Ent. de France," 1837, p. 77, on the flight of butterflies 
 while pairing. See also Mr. G. Eraser, in "Nature," April 20, 1871, 
 p. 489, on the sexual differences of several British butterflies.
 
 INSECTS. 363 
 
 sex; but Mr. Wallace and Mr. Bates have shown * that the 
 females of some species are extremely variable, the males 
 being nearly constant. In a future chapter I shall have 
 occasion to show that the beautiful eye-like spots, or ocelli, 
 found on the wings of many Lepidoptera are eminently 
 variable. I may here add that these ocelli offer a difficulty 
 on the theory of sexual selection; for though appearing to 
 us so ornamental, they are never present in one sex and 
 absent in the other, nor do they ever differ much in the 
 two sexes, f This fact is at present inexplicable; but if it 
 should hereafter be found that the formation of an ocellus 
 is due to some change in the tissues of the wings, for 
 instance, occurring at a very early period of development, 
 we might expect, from what we know of the laws of inherit- 
 ance, that it would be transmitted to both sexes, though 
 arising and perfected in one sex alone. 
 
 On the whole, although many serious objections may be 
 iirged, it seems probable that most of the brilliantly-colored 
 species of Lepidoptera owe their colors to sexual selection, 
 excepting in certain cases, presently to be mentioned, in 
 which conspicuous colors have been gained through mimicry 
 as a protection. From the ardor of the male throughout 
 the animal kingdom he is generally willing to accept any 
 female; and it is the female which usually exerts a choice. 
 Hence, if sexual selection has been efficient with the 
 Lepidoptera, the male, when the sexes differ, ought to be 
 the more brilliantly colored, and this undoubtedly is the 
 case. When both sexes are brilliantly colored and resemble 
 each other the characters acquired by the males appear to 
 have been transmitted to both. We are led to this conclu- 
 sion by cases, even within the same genus, of gradation 
 from an extraordinary amount of difference to identity in 
 color between the two sexes. 
 
 But it may be asked whether the differences in color 
 between the sexes may not be accounted for by other means 
 
 * Wallace on the Papilionidae of the Malayan Region, in "Trans- 
 act. Linn. Soc.," vol. xxv, 1865, pp. 8, 36. A striking case of a rare 
 variety, strictly intermediate between two other well-marked female 
 varieties, is given by Mr. Wallace. See also Mr. Bates, in "Proc. 
 Entomolog. Soc.,'.' Nov. 19, 1866, p. 40. 
 
 f Mr. Bates was so kind as to lay this subject before the Entomo- 
 logical Society, and I have received answers to this effect from several 
 entomologists.
 
 364 THE DESCENT OF MAN. 
 
 "besides sexual selection. Thus the males and females of the 
 same species of butterfly are in several cases known* to 
 inhabit different stations,, the former commonly basking in 
 the sunshine, the latter haunting gloomy forests. It is 
 therefore possible that different conditions of life may have 
 acted directly on the two sexes; but this is not probable, f as 
 in the adult state they are exposed to different conditions 
 during a very short period ; and the larvae of both are 
 exposed to the same conditions. Mr. Wallace believes that 
 the difference between the sexes is due not so much to the 
 males having been modified, as to the females having in all 
 or almost all cases acquired dull colors for the sake 
 of protection. It seems to me, on the contrary, far 
 more probable that it is the males which have been 
 chiefly modified through sexual selection, the females having 
 been comparatively little changed. We can thus under- 
 stand how it is that the females of allied species generally 
 resemble one another so much more closely than do the 
 males. They thus show us approximately the primordial 
 coloring of the parent-species of the group to which they 
 belong. They have, however, almost always been somewhat 
 modified by the transfer to them of some of the successive 
 variations, through the accumulation of which the males 
 were rendered beautiful. But I do not wish to deny that 
 the females alone of some species may have been specially 
 modified for protection. In most cases the males and 
 females of distinct species Avill have been exposed during 
 their prolonged larval state to different conditions, and 
 may have been thus affected ; though with the males any 
 slight change of color thus caused will generally have been 
 masked by the brilliant tints gained through sexual selec- 
 tion. When we treat of birds, I shall have to discuss the 
 whole question, as to how far the differences in color 
 between the sexes are due to the males having been modi- 
 fied through sexual selection for ornamental purposes, or 
 to the females having been modified through natural selec- 
 tion for the sake of protection, so that I will here say but 
 little on the subject. 
 
 In all the cases in which the more common form of equal 
 
 *H. W. Bates, "The Naturalist on the Amazons," vol. ii, 1863, p. 
 228. A. R. Wallace, in " Transact. Liun. Soc.," vol. xxv, 1865, p. 10. 
 
 f On this whole subject see " The Variation of Animals and Plants 
 under Domestication," 1868, vol. ii, chap, xxiii.
 
 INSECTS. 365 
 
 inheritance by both sexes has prevailed, the selection of 
 bright-colored males would tend to make the females 
 bright colored ; and the selection of dull-colored females 
 would tend to make the males dull. If both processes 
 were carried on simultaneously, they would tend to coun- 
 teract each other ; and the final result would depend on 
 whether a greater number of females from being well pro- 
 tected by obscure colors, or a greater number of males by 
 being brightly colored and thus finding partners, succeeded 
 in leaving more numerous offspring. 
 
 In order to account for the frequent transmission of char- 
 acters to one sex alone, Mr. Wallace expresses his belief that 
 the more common form of equal inheritance by both sexes 
 can be changed through natural selection into inheritance 
 by one sex alone, but in favor of this view I can discover 
 no evidence. We know from what occurs under domestica- 
 tion that new characters often appear, which from the first 
 are transmitted to one sex alone ; and by the selection of 
 such variations there would not be the slightest difficulty 
 in giving bright colors to the males alone, and at the same 
 time or subsequently, dull colors to the females alone. In 
 this manner the females of some butterflies and moths 
 have, it is probable, been rendered inconspicuous for the 
 sake of protection, and widely different from their males. 
 
 I am, however, unwilling without distinct evidence to 
 admit that two complex processes of selection, each requir- 
 ing the transference of new characters to one sex alone, 
 have been carried on with a multitude of species that the 
 males have been rendered more brilliant by beating their 
 rivals, and the females more dull colored by having escaped 
 from their enemies. The male, for instance, of the common 
 brimstone butterfly (Gonepteryx), is of a far more intense 
 yellow than the female, though she is equally conspicuous; 
 and it does not seem probable that she specially acquired 
 her pale tints as a protection, though it is probable that 
 the male acquired his bright colors as a sexual attraction. 
 The female of Anthocharis cardamines does not possess 
 the beautiful orange wing-tips of the male ; consequently 
 she closely resembles the white butterflies (Pieris) so com- 
 mon in our gardens; but we have no evidence that this 
 resemblance is beneficial to her. As, on the other hand, she 
 resembles both sexes of several other species of the genus 
 inhabiting various quarters of the world, it is probable that
 
 366 THE DESCENT OF MAN. 
 
 she has simply retained to a large extent her primordial 
 colors. 
 
 Finally, as we have seen, various considerations lead to the 
 conclusion that with the greater number of brilliantly col- 
 ored Lepidoptera it is the male which has been chiefly 
 modified through sexual selection; the amount of difference 
 between the sexes mostly depending on the form of inherit- 
 ance which has prevailed. Inheritance is governed by so 
 many unknown laws or conditions that it seems to us to act 
 in a capricious manner;* and we can thus, to a certain ex- 
 tent, understand how it is that with closely allied species 
 the sexes either differ to an astonishing degree, or are iden- 
 tical in color. As all the successive steps in the process of 
 variation are necessarily transmitted through the female, a 
 greater or less number of such steps might readily become 
 developed in her; and thus we can understand the frequent 
 gradations from an extreme difference to none at all between 
 the sexes of allied species. These cases of gradation, it 
 may be added, are much too common to favor the supposi- 
 tion that we here see females actually undergoing tile 
 process of transition and losing their brightness for the 
 sake of protection; for we have every reason to conclude 
 that at any one time the greater number of species are in a 
 fixed condition. 
 
 Mimicry. This principle was first made clear in an ad- 
 mirable paper by Mr. Bates, f who thus threw a flood of 
 light on many obscure problems. It had previously been 
 observed that certain butterflies in South America belong- 
 ing to quite distinct families resembled the Heliconidae so 
 closely in every stripe and shade of color that they could 
 not be distinguished save by an experienced entomologist. 
 As the Heliconidas are colored in their usual manner, while 
 the others depart from the usual coloring of the groups to 
 which they belong, it is clear that the latter are the imi- 
 tators, and the Helicpnidae the imitated. Mr. Bates further 
 observed that the imitating species are comparatively rare, 
 while the imitated abound, and that the two sets live min- 
 gled together. From the fact of the Heliconidae being 
 
 * " The Variation of Animals and Plants under Domestication," voL 
 ii, chap, xii, p. 17. 
 f "Transact. I4nn. Soc.," vol. xxiii, 1863, p. 495.
 
 INSECTS. 367 
 
 conspicuous and beautiful insects, yet so numerous in indi- 
 viduals and species, he concluded that they must be pro- 
 tected from the attacks of enemies by some secretion or 
 odor; and this conclusion has now been amply confirmed,* 
 especially by Mr. Belt. Hence Mr. Bates inferred that the 
 butterflies which imitate the protected species have acquired 
 their present marvelously deceptive appearance through 
 variation and natural selection, in order to be mistaken for 
 the protected kinds, and thus to escape being devoured. 
 No explanation is here attempted of the brilliant colors of 
 the imitated, but only of the imitating butterflies. "We 
 must account for the colors of the former in the same gen- 
 eral manner as in the cases previously discussed in this 
 chapter. Since the publication of Mr. Bates' paper similar 
 and equally striking facts have been observed by Mr. Wal- 
 lace in the Malayan region, by Mr. Trimen in S. Africa, 
 and by Mr. Eiley in the United States, f 
 
 As some writers have felt much difficulty in understand- 
 ing how the first steps in the process of mimicry could 
 have been effected through natural selection, it may be well 
 to remark that the process probably commenced long ago 
 between forms not widely dissimilar in color. In this case 
 even a slight variation would be beneficial if it rendered 
 the one species more like the other; and afterward the 
 imitated species might be modified to an extreme degree 
 through sexual selection or other means, and if the changes 
 were gradual the imitators might easily be led along the 
 same track, until they differed to an equally extreme degree 
 from their original condition; and they would thus ulti- 
 mately assume an appearance or coloring wholly unlike 
 that of the other members of the group to which they 
 belonged. It should also be remembered that many species 
 of Lepidoptera are liable to considerable and abrupt varia- 
 tions in color. A few instances have been given in this 
 chapter; and many more may be found in the papers of 
 Mr. Bates and Mr. Wallace. 
 
 *"Proc. Ent. Soc.," Dec. 3, 1866, p. 45. 
 
 ,f Wallace, "Transact. Linn. Soc.," vol. xxv, 1865, p. 1 ; also 
 ''Transact. Ent. Soc.," vol. iv (3d series), 1867, p. 301. Trimen, 
 "Linn. Transact.," vol. xxvi, 1869, p. 497. Riley, "Third Annual 
 Report on the Noxious Insects of Missouri," 1871, pp. 163-168. This 
 latter essay is valuable, as Mr. Riley here discusses all the objections 
 which have been raised against Mr. Bates' theory.
 
 368 THE DESCENT OF MAN. 
 
 With several species the sexes are alike, and imitate the 
 two sexes of another species. But Mr. Trimen gives, in 
 the paper already referred to, three cases in which the sexes 
 of the imitated form differ from each other in color, and 
 the sexes of the imitating form differ in a like manner. 
 Several cases have also been recorded where the females 
 alone imitate brilliantly-colored and protected species, the 
 males retaining " the normal aspect of their immediate con- 
 geners." It is here obvious that the successive variations 
 by which the female has been modified have been trans- 
 mitted to her alone. It is, however, probable that some of 
 the many successive variations would have been transmitted 
 to, and developed in, the males had not such males been 
 eliminated by being thus rendered less attractive to the 
 females; so that only those variations were preserved which 
 were from the first strictly limited in their transmission to 
 the female sex. We have a partial illustration of these 
 remarks in a statement by Mr. Belt; * that the males of 
 some of the Leptalides, which imitate protected species, 
 still retain in a concealed manner some of their original 
 characters. Thus in the males " the upper half of the 
 lower wing is of a pure white, while all the rest of the wings 
 is barred and spotted with black, red and yellow, like the 
 species they mimic. The females have not this white 
 patch, and the males usually conceal it by covering it with 
 the upper wing, so that I cannot imagine its being of any 
 other use to them than as an attraction in courtship, when 
 they exhibit it to the females, and thus gratify their deep- 
 seated preference for the normal color of the order to which 
 the Leptalides belong." 
 
 Bright Colors of Caterpillars. While reflecting on the 
 beauty of many butterflies it occurred to me that some 
 caterpillars were splendidly colored; and as sexual selection 
 could not possibly have here acted, it appeared rash to 
 attribute the beauty of the mature insect to this agency, 
 unless the bright colors of their larva? could be somehow 
 explained. In the first place, it may be observed that the 
 colors of caterpillars do not stand in any close correlation 
 with those of the mature insect. Secondly, their bright 
 colors do not serve in any ordinary manner as a protection. 
 
 * " The Naturalist in Nicaragua," 1874, p. 385.
 
 INSECTS, 369 
 
 Mr. Bates informs me, as an instance of this, that the most 
 conspicuous caterpillar which he ever beheld (that of a 
 Sphinx) lived on the large green leaves of a tree on the 
 open llanos of South America; it was about four inches in 
 length, transversely banded with black and yellow, and 
 with its head, legs and tail of a bright red. Hence it 
 caught the eye of any one who passed by, even at the 
 distance of many yards, and no doubt that of every passing 
 bird. 
 
 I then applied to Mr. Wallace, who has an innate genius 
 for solving difficulties. After some consideration he replied: 
 " Most caterpillars require protection, as may be inferred 
 from some kinds being furnished with spines or irritating 
 hairs and from many being colored green like the leaves on 
 which they feed, or being curiously like the twigs of the trees 
 on which they live." Another instance of protection, fur- 
 nished me by Mr. J. Mansel Weale, may be added, namely, 
 that there is a caterpillar of a moth which lives on the 
 mimosas in S. Africa, and fabricates for itself a case quite 
 indistinguishable from the surrounding thorns. From 
 such considerations Mr. Wallace thought it probable that 
 conspicuously colored caterpillars were protected by having 
 u nauseous taste; but as their skin is extremely tender, 
 and as their intestines readily protrude from a wound, a 
 slight peck from the beak of a bird would be as fatal to 
 them as if they had been devoured. Hence, as Mr. Wal- 
 lace remarks, " distastefulness alone would be insufficient 
 to protect a caterpillar unless some outward sign indicated 
 to its would-be destroyer that its prey was a disgusting 
 morsel." Under these circumstances it would be highly 
 advantageous to a caterpillar to be instantaneously and 
 certainly recognized as unpalatable by all birds and other 
 animals. Thus the most gaudy colors would be service- 
 able, and might have been gained by variation and the 
 survival of the most easily recognized individuals. 
 
 This hypothesis appears at first sight very bold, but 
 when it was brought before the Entomological Society* it 
 was supported by various statements; and Mr. J. Jenner 
 Weir, who keeps a large number of birds in an aviary, 
 informs me that he has made many trials and finds no 
 
 * " Proc. Entoinolog. Soc.," Dec. 3, 1866, p. 45, and March 4. 1867, 
 p. 80.
 
 370 THE DESCENT OF MAN. 
 
 exception to the rule that all caterpillars of nocturnal and 
 retiring habits with smooth skins, all of a green color and 
 all which imitate twigs are greedily devoured by his birds. 
 The hairy and spiiiose kinds are invariably rejected, as 
 were four conspicuously colored species. When the birds 
 rejected a caterpiller they plainly showed by shaking their 
 heads and cleansing their beaks that they were disgusted 
 by the taste.* Three conspicuous kinds of caterpillars and 
 moths were also given to some lizards and frogs by Mr. A. 
 Butler and were rejected, though other kinds were eagerly 
 eaten. Thus the probability of Mr. Wallace's view is con- 
 firmed, namely, that certain caterpillars have been made 
 conspicuous for their own good, so as to be easily recog- 
 nized by their enemies, on nearly the same principle that 
 poisons are sold in colored bottles by druggists for the good 
 of man. We cannot, however, at present thus explain the 
 elegant diversity in the colors of many caterpillars; but 
 any species which had at some former period acquired a 
 dull, mottled or striped appearance, either in imitation of 
 surrounding objects or from the direct action of climate, 
 etc., almost certainly would not become uniform in color 
 when its tints were rendered intense and bright; for in 
 order to make a caterpillar merely conspicuous there would 
 be no selection in any definite direction. 
 
 Summary and Concluding Remarks on Insects. Looking 
 back to the several orders we see that the sexes often differ 
 in various characters, the meaning of which is not in the 
 least understood. The sexes, also, often differ in their 
 organs of sense and means of locomotion, so that the males 
 may quickly discover and reach the females. They differ 
 still oftener in the males possessing diversified contrivances 
 for retaining the females when found. We are, however, 
 here concerned only in a secondary degree with sexual dif- 
 ferences of these kinds. 
 
 In almost all the orders the males of some species, even 
 of weak and delicate kinds, are known to be highly pug- 
 
 *See Mr. J. Jenner Weir's paper on Insects and Insectivorous 
 Birds, in "Transact. Ent. Soc.," 1869, p. 21; also Mr. Butler's paper, 
 ibid., p. 27. Mr. Riley has given analogous facts in the "Third 
 Annual Report on the Noxious Insects of Missouri," 1871, p. 148. 
 Some opposed cases are, however, given by Dr. Wallace and M. H. 
 d'Orville; see " Zoological Record," 1869, p. 349.
 
 INSECTS. 371 
 
 nacious; and some few are furnished with special weapons 
 for fighting with their rivals. But the law of battle does 
 not prevail nearly so widely with insects as with the higher 
 animals. Hence it probably arises that it is in only a 
 few cases that the males have been rendered larger and 
 stronger than the females. On the contrary, they are 
 usually smaller, so that they may be developed within a 
 shorter time, to be ready in large numbers for the emerg- 
 ence of the females. 
 
 In two families of the Homoptera and in three of the 
 Orthoptera, the males alone possess sound-producing organs 
 in an efficient state. These are used incessantly during the 
 breeding-season, not only for calling the females, but ap- 
 parently for charming or exciting them in rivalry with 
 other males. Xo one who admits the agency of selection 
 of any kind, will, after reading the above discussion, dis- 
 pute that these musical instruments have been acquired 
 through sexual selection. In four other orders the mem- 
 bers of one sex, or more commonly of both sexes, are pro- 
 vided with organs for producing various sounds, which ap- 
 parently serve merely as call-notes. When both sexes are 
 thus provided the individuals which were able to make the 
 loudest or most continuous noise would gain partners before 
 those 'which were less noisy, so that their organs have proba- 
 bly been gained through sexual selection. It is instructive 
 to reflect on the wonderful diversity of the means for pro- 
 ducing sound possessed by the males alone, or by both 
 sexes in no less than six orders. We thus learn how effectual 
 sexual selection has been in leading to modifications which 
 sometimes, as with the Homoptera, relate to important 
 parts of the organization. 
 
 From the reasons assigned in the last chapter, it is proba- 
 ble that the great horns possessed by the. males of many 
 Lamellicorn, and some other beetles, have been acquired as 
 ornaments. From the small size of insects we are apt to 
 undervalue their appearance. If we could imagine a male 
 Chalcosoma (see fig. 16), with its polished bronzed coat of mail 
 and its vast complex horns, magnified to the size of a 
 horse, or, even of a dog, it would be one of the most impos- 
 ing animals in the world. 
 
 The coloring of insects is a complex and obscure subject. 
 When the male differs slightly from th$ female, and 
 neither are brilliantly colored, it is probable that the sexes
 
 372 THE DESCENT OF MAN. 
 
 have varied in a slightly different manner, and that the 
 variations have been transmitted by each sex to the same, 
 without any benefit or evil thus accruing. When the 
 male is brilliantly colored and differs conspicuously from 
 the female, as with some dragon-flies and many butterflies, 
 it is probable that he owes his colors to sexual selection , 
 while the female has retained a primordial or very ancient 
 type of coloring, slightly modified by the agencies before 
 explained. But in some cases the female has apparently 
 been made obscure by variations transmitted to her alone, 
 as a means of direct protection; and it is almost certain 
 that she has sometimes been made brilliant, so as to imitate 
 other protected species inhabiting the same district. When 
 the sexes resemble each other and both are obscurely colored 
 there is no doubt that they have been in a multitude of 
 cases so colored for the sake of protection. So it is in some 
 instances when both are brightly colored, for they thus imi- 
 tate protected species, or resemble surrounding objects such 
 as flowers; or they give notice to their enemies that they 
 are unpalatable. In other cases in which the sexes resem- 
 ble each other and are both brilliant, especially when the 
 colors are arranged for display, we may conclude that they 
 have been gained by the male sex as an attraction, and have 
 been transferred to the female. We are more especially led 
 to this conclusion whenever the same type of coloration pre- 
 vails throughout a whole group, and we find that the males 
 of some species differ widely in color from the females, 
 while others differ slightly or not at all with intermediate 
 gradations connecting these extreme states. 
 
 In the same manner as bright colors have often been par- 
 tially transferred from the males to the females, so it has 
 been with the extraordinary horns of many Lamellicorn 
 and some other beetles. So, again, the sound-producing 
 organs proper to the males of the Homoptera and Orthop- 
 tera have generally been transferred in a rudimentary, or 
 even in a nearly perfect condition, to the females ; yet not 
 sufficiently perfect to be of any use. It is also an interest- 
 ing fact, as bearing on sexual selection, that the stridu- 
 lating organs of certain male Orthoptera are not fully 
 developed until the last moult; and that the colors of cer- 
 tain male dragon-flies are not fully developed until some 
 little time after their emergence from the pupal state, and 
 when they are ready to breed.
 
 INSECTS. 373 
 
 Sexual selection implies that the more attractive indi- 
 viduals are preferred by the opposite sex ; and as with 
 injects, when the sexes differ, it is the male which, with 
 some rare exceptions, is the more ornamented, and departs 
 more from the type to which the species belongs; and as it 
 is the male which searches eagerly for the female, we must 
 suppose that the females habitually or occasionally prefer 
 the more beautiful males, and that these have thus acquired 
 their beauty. That the females in most or all the orders 
 would have the power of rejecting any particular male, is 
 probable from the many singular contrivances possessed by 
 the males, such as great jaws, adhesive cushions, spines, 
 elongated legs, etc., for seizing the female; for these con- 
 trivances show that there is some difficulty in the act, 
 so that her concurrence would seem necessary. Judging 
 from what we know of the perceptive powers and affections 
 of various insects, there is no antecedent improbability in 
 sexual selection having come largely into play; but we have 
 as yet no direct evidence on this head, and some facts are 
 opposed to the belief. Nevertheless, when we see many 
 males pursuing the same female, we can hardly believe that 
 the pairing is left to blind chance that the female exerts 
 no choice, and is not influenced by the gorgeous colors or 
 other ornaments with which the male is decorated. 
 
 If we admit that the females of the Homoptera and 
 Orthoptera appreciate the musical tones of their male part- 
 ners, and that the various instruments have been perfected 
 through sexual selection, there is little improbability in the 
 females of other insects appreciating beauty in form or 
 color, and consequently in such characters having been 
 thus gained by the males. But from the circumstance of 
 color being so variable, and from its having been so ol ten 
 modified for the sake of protection, it is difficult to decide 
 in how large a proportion of cases sexual selection has 
 played a part. This is more especially difficult in those 
 orders, such as Orthoptera, Hymenoptera, and Coleoptera, 
 in which the two sexes rarely differ much in color; for we 
 are then left to mere analogy. With the Coleoptera, how- 
 ever, as .before remarked, it- is in the great Lamellicorn 
 group, placed by some authors at the head of the order, 
 and in which we sometimes see a mutual attachment be- 
 tween the sexes, that we find the males of some species pos- 
 sessing weapons for sexual strife, others furnished with
 
 374 THE DESCENT OF MAN. 
 
 wonderful horns, many with stridulating organs, and others 
 ornamented with splendid metallic tints. Hence it seems 
 probable that all these characters have been gained through 
 the same means, namely, sexual selection. With butterflies 
 we have the best evidence, as the males sometimes take 
 pains to display their beautiful colors; and we cannot be- 
 lieve that they would act thus, unless the display was of 
 use to them in their courtship. 
 
 When we treat of birds we shall see that they present in 
 their secondary sexual characters the closest analogy with 
 insects. Thus many male birds are highly pugnacious, and 
 some are furnished with special weapons for fighting with 
 their rivals. They possess organs which are used during 
 the breeding-season for producing vocal and instrumental 
 music. They are frequently ornamented with combs, 
 horns, wattles and plumes of the most diversified kinds, 
 and are decorated with beautiful colors, all evidently for 
 the sake of display. We shall find that, as with insects, 
 both sexes in certain groups are equally beautiful, and are 
 equally provided with ornaments which are usually confined 
 to the male sex. In other groups both sexes are equally 
 plain-colored and unornamented. Lastly, in some few 
 anomalous cases the females are more beautiful than the 
 males. We shall often find, in the same group of birds, 
 every gradation from no difference between the sexes to an 
 extreme difference. We shall see that female birds, like 
 female insects, often possess more or less plain traces or 
 rudiments of characters which properly belong to the males 
 and are of use only to them. The analogy, indeed, in all 
 these respects between birds and insects is curiously close. 
 Whatever explanation applies to the one class probably 
 applies to the other; and this explanation, as we shall here- 
 after attempt to show in further detail, is sexual selection.
 
 FISHES. 375 
 
 CHAPTER XII. 
 
 SECONDARY SEXUAL CHARACTERS OF FISHES, 
 AMPHIBIANS AND REPTILES. 
 
 FISHES: Courtship and battles of the males Larger size of the 
 females Males, bright colors and ornamental appendages ; 
 other strange characters Colors and appendages acquired by 
 the males during the breeding-season alone Fishes with both 
 sexes brilliantly colored Protective colors The less conspicu- 
 ous colors of the female cannot be accounted for on the principle 
 of protection Male fishes building nests and taking charge of 
 the ova and young. AMPHIBIANS: Differences in structure and 
 color between the sexes Vocal organs. REPTILES : Chelonians 
 Crocodiles Snakes, colors in some cases protective Lizards, 
 battles of Ornamental appendages Strange differences in 
 structure between the sexes Colors Sexual differences almost 
 as great as with birds. 
 
 WE have now arrived at the great sub-kingdom of the 
 Vertebrata, and will commence with the lowest class, that 
 of fishes. The males of Plagiostomous fishes (sharks, rays) 
 and of Chimseroid fishes are provided with claspers which 
 serve to retain the female, like the various structures 
 possessed by many of the lower animals. Besides the 
 claspers, the males of many rays have clusters of strong 
 sharp spines on their heads and several rows along "the 
 upper outer surface of their pectoral fins." These are 
 present in the males of some species, which have other 
 parts of their bodies smooth. They are only temporarily 
 developed during the breeding-season ; and Dr. Giinther 
 suspects that they are brought into action as prehensile 
 organs by the doubling inward and downward of the two 
 sides of the body. It is a remarkable fact that the females 
 and not the males of some species, as of Raia davata, have 
 their backs studded with large hook -formed spines. * 
 
 The males alone of the capelin (Mallotus villosus, one of 
 
 *Yarrell's "Hist, of British Fishes," vol. ii, 1836, pp. 417, 425, 
 436. Dr. Giinther informs me that the spines in fi. clavata are 
 peculiar to the female.
 
 376 THE DESCENT OF MAN. 
 
 Salmonidae) are provided with a ridge of closely-set, brush- 
 like scales, by the aid of which two males, one on each side, 
 hold the female, while she runs with great swiftness on 
 the sandy beach and there deposits her spawn.* The 
 widely distinct Monacantlms scopas presents a somewhat 
 analogous structure. The male, as Dr. Giinther informs 
 me, has a cluster of stiff, straight spines, like those of a 
 * comb, on the sides of the tail ; and these in a specimen 
 six inches long were nearly one and a half inches in 
 length; the female has in the same place a cluster of bristles, 
 which may be compared with those of a toothbrush. In 
 another species, M. peronii, the male has a brush like that 
 possessed by the female of the last species, while the sides 
 of the tail in the female are smooth. In some other 
 species of the same genus the tail can be perceived to 
 be a little roughened in the male and perfectly smooth in 
 the female; and lastly in others, both sexes have smooth 
 
 The males of many fish fight for the possession of the 
 females. Thus the male stickleback ( Gasterosteus leiurus) 
 has been described as " mad with delight " when the female 
 comes out of her hiding-place and surveys the nest which 
 he has made for her. " He darts round her in every direc- 
 tion, then to his accumulated materials for the nest, then 
 back again in an instant; and as she does not advance he 
 endeavors to push her with his snout, and then tries to pull 
 her by the tail and side-spine to the nest."f The males are 
 said to be polygamists; J they are extraordinarily bold and 
 pugnacious, while "the females are quite pacific." Their 
 battles are at times desperate; "for these puny combatants 
 fasten tight on each other for several seconds, tumbling 
 over and over again, until their strength appears completely 
 exhausted." With the rough-tailed stickleback (G. trachu- 
 rus) the males while fighting swim round and round each 
 other, biting and endeavoring to pierce each other with 
 their raised lateral spines. The same writer adds, "the 
 bite of these little furies is very severe. They also use their 
 
 *"The American Naturalist," April, 1871, p. 119. 
 f See Mr. R. Warington's interesting articles in " Annals and Mag. 
 of Nat. Hist.," Oct., 1852, and Nov., 1855. 
 J Noel Humphreys, "River Gardens," 1857. 
 Loudon's " Mag. of Nat. History," vol. iii, 1880, p. 381.
 
 FISHES. 377 
 
 lateral spines with such fatal effect that I have seen one 
 during a battle absolutely rip his opponent quite open, so 
 that he sank to the bottom and died." When a fish is con- 
 quered, "his gallant bearing forsakes him; his gay colors 
 fade away; and he hides his disgrace among his peaceable 
 companions, but is for some time the constant object of his 
 conqueror's persecution." 
 
 The male salmon is as pugnacious as the little stickle- 
 back; and so is the male trout, as I hear from Dr. Giinther. 
 Mr. Shaw saw a violent contest between two male salmon 
 which lasted the whole day; and Mr. R. Buist, Superin- 
 tendent of Fisheries, informs me that he has often watched 
 from the bridge at Perth the males driving away their 
 rivals whib the females were spawning. The males "are 
 constantly fighting and tearing each other on the spawning- 
 beds, and many so injure each other as to cause the death 
 of numbers, many being seen swimming near the banks of 
 the river in a state of exhaustion, and apparently in a 
 dying state." * Mr. Buist informs me that in June, 1868, 
 the keeper of the Stormontfield Breeding-Ponds visited the 
 northern Tyne and found about 300 dead salmon, all of 
 which with one exception were males; and he was convinced 
 that they had lost their lives by fighting. 
 
 The most curious point about the male salmon is that 
 during the breeding-season, besides a light change in color, 
 "the lower jaw elongates, and a cartilaginous pro- 
 jection turns upwarl from the point, which, when the 
 jaws are closed, occupies a deep cavity between the inter- 
 maxillary bones of the upper jaw."f (Figs. 27 and 28.) 
 In our salmon this change of structure lasts only during 
 the breeding-season; but in the Salmo lycaodon of North- 
 western America the change, as Mr. J. K. Lord J believes, 
 is permanent and best marked in the older males which have 
 previously ascended the rivers. In these old males the 
 jaw becomes developed into an immense hook-like projec- 
 tion and the teeth grow into regular fangs, often more than 
 
 *"The Field," June 29, 1867. For Mr. Shaw's statement, see 
 " Edinburgh Review," 1843. Another experienced observer (Scrope's 
 "Days of -Salmon Fishing," p. 60) remarks that like the stag, the 
 male would, if he could, keep all other males away. 
 
 f Yarrell, "History of British Fishes," vol. ii, 1836, p. 10. 
 % " The Naturalist in Vancouver's Island," vol. i, 1866, p. 54
 
 378 THE DESCENT OF JUAN. 
 
 half an inch in length. With the European salmon, 
 according to Mr. Lloyd,* the temporary hook -like structure 
 
 Kg. iff. Head of male common salmon (Salmo solar) during the breedlng- 
 
 [Thls drawing, as well as all the others in the present chapter, have been exe- 
 cuted by the well-known artist, Mr. G. Ford, from specimens in the British 
 Museum, under the kind superintendence of Dr. Qunther.] 
 
 to strengthen and protect the jaws, when one male 
 charges another with wonderful violence; but the greatly 
 developed teeth of the male American salmon may be com- 
 
 "Scandinavian Adventures," vol. i, 1854, pp. 100, 104
 
 FISHES. 379 
 
 pared with the tusks of many male mammals, and they 
 indicate an offensive rather than a protective purpose. 
 
 The salmon is not the only fish in which the teeth differ 
 in the two sexes; as this is the case with many rays. In 
 
 Fig. 2a Head of female salmon. 
 
 the thornback (Raia Clavatd) the adult male has sharp, 
 pointed teeth, directed backward, while those of the female 
 are' broad" and flat, and form a pavement; so that these 
 teeth differ in the two sexes of the same species more than 
 is usual in distinct genera of the same family. The teeth 
 of the male become sharp only when he is adult; while 
 young they are broad and flat like those of the female. A9
 
 380 THE DESCENT OF MAN. 
 
 so frequently occurs with secondary sexual characters, both 
 sexes of some species of rays (for instance R. batis), when 
 adult, possess sharp, pointed teeth; and here a character, 
 proper to and primarily gained by the male, appears to have 
 been transmitted to the offspring of both sexes. The teeth 
 are likewise pointed in both sexes of R. maculata, but only 
 when quite adult; the males acquiring them at an earlier 
 age than the females. We shall hereafter meet with anal- 
 ogous cases in certain birds, in which the male acquires the 
 plumage common to both sexes when adult, at a somewhat 
 earlier age than does the female. With other species of 
 rays the males even when old never possess sharp teeth, and 
 consequently the adults of both sexes are provided with 
 broad, flat teeth like those of the young, and like those of 
 the mature females of the above-mentioned species.* As 
 the rays are bold, strong and voracious fish, we may suspect 
 that the males require their sharp teeth for fighting with 
 their rivals; but as they possess many parts modified and 
 adapted for the prehension of the female, it is possible that 
 their teeth may be used for this purpose. 
 
 In regard to size, M. Car onnierf maintains that the 
 female of almost all fishes is larger than the male; and Dr. 
 Giinther does not know of a single instance in which the 
 male is actually larger than the female. With some 
 Cyprinodonts the male is not even half as large. As in 
 many kinds of fishes the males habitually fight together, it 
 is surprising that they have not generally become larger 
 and stronger "than the females through the effects of sexual 
 selection. The males suffer from their small size, for, 
 according to M. Carbonnier, they are liable to be devoured 
 by the females of their own species when carnivorous, and 
 no doubt by other species. Increased size must be in some 
 manner of more importance to the females than strength 
 and size are to the males for fighting with other males; 
 and this perhaps is to allow of the production of a vast 
 number of ova. 
 
 In many species the male alone is ornamented with 
 bright colors; or these are much brighter in the male than 
 the female. The male, also, is sometimes provided with 
 
 * See Tarrell's account of the rays in his " Hist, of British Fishes,'* 
 rol, ii, 1836, p. 416, with an excellent figure, a.p.c( pp. 4^2, 43$, 
 
 f As quoted in " The Farmer," 18R, p. 8ft&
 
 FISHES. 381 
 
 appendages which appear to be of no more use to him for 
 the ordinary purposes of life than are the tail feathers to 
 the peacock. I am indebted for most of the following 
 facts to the kindness of Dr. Giinther. There is reason 
 to suspect that many tropical fishes differ sexually in color 
 and structure; and there are some striking cases with our 
 British fishes. The male Callionymus lyra has been called 
 the gemmeous dragonet " from its brilliant gem-like colors." 
 
 Fig. 29. Callionymus lyra Upper figure, male ; lower figure, female. 
 N. B. The lower figure is more reduced than the upper. 
 
 When fresh caught from the sea the body is yellow of 
 various shades, striped and spotted with vivid blue on the 
 head; the dorsel fins are pale brown with dark longitudinal 
 bands; the ventral, caudal and anal fins being bluish-black. 
 The female, or sordid dragonet, was considered by Lin- 
 naeus and by many subsequent naturalists as a distinct 
 species; it is of a dingy reddish-brown with the dorsal fin 
 brown and the other fins white. The sexes differ also in 
 the proportional size of the head and mouth and in the 
 position of the eyes;* but the most striking difference is 
 the extraordinary elongation in the male (fig. 29) of the 
 
 *I have drawn up this description from Yarrell's "British 
 Fishes," vol. i, 1836, pp. 261, 266.
 
 382 THE DESCENT OF MAN. 
 
 dorsal fin. Mr. W. Saville Kent remarks that this ' ' sin- 
 gular appendage appears from my observations of the 
 species in confinement to be subservient to the same end 
 as the wattles, crests and other abnormal adjuncts of the 
 male in gallinaceous birds for the purpose of fascinating 
 their mates."* The young males resemble the adult 
 females in structure and color. Throughout the genus 
 Callionymusf the male is generally much more brightly 
 spotted than the female, and in several species, not only 
 the dorsal, but the anal fin is much elongated in the males. 
 
 The male of the Coitus scorpius, or sea-scorpion, is 
 slenderer and smaller than the female. There is also a 
 great difference in color between them. It is difficult, as 
 Mr. LloydJ remarks, " for any one who has not seen this 
 fish during the spawning season when its hues are brighest 
 to conceive the admixture of brilliant colors with which it, 
 in other respects so ill-favored, is at that time adorned." 
 Both sexes of the Labrus mixtus, although very different 
 in color, are beautiful; the male being orange with bright 
 blue stripes and the female bright red with some black 
 spots on the back. 
 
 In the very distinct family of the Cyprinodontidae 
 inhabitants of the fresh waters of foreign lands the sexes 
 sometimes differ much in various characters. In the male 
 of the Mollienesia petenensis,% the dorsal fin is greatly de- 
 veloped and is marked with a row of large, round, ocellated, 
 bright-colored spots; while the same fin in the female is 
 smaller, of a different shape, and marked only with irregu- 
 larly curved brown spots. In the male the basal margin of 
 the anal fin is also a little produced and dark colored. In 
 the male of an allied form, the Xiphophorus Hellerii (fig. 
 30}, the inferior margin of the caudal fin is developed into 
 a long filament, which, as I hear from Dr. Giinther, is 
 striped with bright colors. This filament does not contain 
 any muscles, and apparently cannot be of any direct use to 
 the fish. As in the case of the Callionymus, the males 
 
 *" Nature," July, 1873, p. 264. 
 
 f " Catalogue of Acantb. Fishes in the British Museum," by Dr. 
 Utinther, 161, pp. 138-151. 
 
 $ " Game Birds of Sweden," etc., 1867, p. 466. 
 
 With respect to this and the following species I am indebted to 
 Dr. Qtlnther for information; set- also his paper on the " Fishes of 
 Central America," in "Transact. Zoolog. Soc.," vol. vi, 1868, p. 485.
 
 FISHES. 383 
 
 while young resemble the adult females in color and struct- 
 ure. Sexual differences such as these may be strictly com- 
 pared with those which are so frequent with gallinaceous 
 birds.* 
 
 In a siluroid fish, inhabiting the fresh waters of South 
 America, the Plecostomus barbatus\ (fig. 31), the male has 
 its mouth and inter-operculum fringed with a beard of stiff 
 hairs, of which the female shows hardly a trace. These 
 
 Fig. 30. Xiphophorus Hellerii. Upper figure, male ; lower figure, female. 
 
 hairs are of the nature of scales. In another species of the 
 same genus, soft flexible tentacles project from the front 
 part of the head of the male, which are absent in the. 
 female. These tentacles are prolongations of the true skin, 
 and therefore are not homologous with the stiff hairs of the 
 former species; but it can hardly be doubted that both 
 serve the same purpose. What this purpose may be it is 
 difficult to conjecture; ornament does not here seem prob- 
 able, but we can hardly suppose that stiff hairs and flexible 
 
 *Dr. Giinther makes this remark; "Catalogue of Fislies in the 
 British Museum," vol. iii, 1861, p. 141. 
 
 t See Dr. Giinther on this genus, in " Proc. Zoolog. Soc.," 1868, p.
 
 THE DESCENT OF MAN. 
 
 Fig. 81. Plecostomus barbatus. Upper figure, head of male ; lower figure, 
 female.
 
 FISHES. 385 
 
 filaments can be useful in any ordinary way to the males 
 alone. In that strange monster, the Chimcera monstrosa, 
 the male has a hook-shaped bone on the top of the head, 
 directed forward, with its end rounded and covered with 
 sharp spines ; in the female " this crown is altogether 
 absent," but what its use may be to the male is utterly 
 unknown.* 
 
 The structures as yet referred to are permanent in the 
 male after he has arrived at maturity; but with some Blen- 
 nies, and in another allied genus, f a crest is developed on 
 the head of the male only during the breeding season, and 
 the body at the same time becomes more brightly colored. 
 There can be little doubt that this crest serves as a tem- 
 porary sexual ornament, for the female does not exhibit a 
 trace of it. In other species of the same genus both sexes 
 possess a crest, and in at least one species neither sex is 
 thus provided. In many of the Chromidae, for instance in 
 Geophagus and especially in Cichla, the males, as I hear 
 from Prof. Agassiz,J have a conspicuous protuberance on 
 the forehead which is wholly wanting in the females and 
 in the young males. Prof. Agassiz adds: "I have often 
 observed these fishes at the time of spawning when the 
 protuberance is largest, and at other seasons when it is 
 totally wanting, and the two sexes show no difference 
 whatever in the outline of the profile of the head. I 
 never could ascertain that it subserves any special func- 
 tion, and the Indians on the Amazon know nothing about 
 its use." These protuberances resemble in their periodical 
 appearance the fleshy carbuncles on the heads of certain 
 Birds; but whether they serve as ornaments must remain at 
 present doubtful. 
 
 I hear from Prof. Agassiz and Dr. Giinther that the 
 males of those fishes which differ permanently in color 
 from the females often become more brilliant during 
 the breeding season. This is likewise the case with a 
 multitude of fishes, the sexes of which are identical in 
 
 P. Bnckland in "Land and Water," July, 1868, p. 377, with a 
 figure. Many other cases could be added of structures peculiar to 
 the male, of"which the uses are not known. 
 
 f Dr. Giinther, "Catalogue of Fishes," vol. iii, pp. 221 and 240. 
 
 j See also " A Journey in Brazil," by Prof, and Mrs. Agassiz, 1868, 
 p. 220.
 
 386 THE DESCENT OF MAN. 
 
 color at all other seasons of the year. The tench, roach 
 and perch may be given as instances. The male salmon 
 at this season is "marked on the cheeks with orange- 
 colored stripes, which give it the appearance of a Labrus, 
 and the body partakes of a golden-orange tinge. The 
 females are dark in color, and are commonly called black- 
 fish/'* An analogous and even greater change takes place 
 with the Sal/no eriox or bull trout ; the males of the char 
 (8. umbla) are likewise at this season rather brighter in 
 color than the females, f The colors of the pike ( Esox 
 reticulatus) of the United States, especially of the male, 
 become, during the breeding-season, exceedingly intense, 
 brilliant, and iridescent. J Another striking instance out 
 of many is afforded by the male stickleback (Gastcrosteus 
 leiurus), which is described by Mr. Warmgton, as being 
 then "beautiful beyond description." The back and eyes 
 of the female are simply brown and the belly white. The 
 eyes of the male, on the other hand, are " of the most 
 splendid green, having a metallic luster like the green 
 feathers of some humming-birds. The throat and belly are 
 of a bright crimson, the back of an ashy-green, and the 
 whole fish appears as though it were somewhat translucent 
 and glowed with an internal incandescence." After the 
 breeding-season these colors all change, the throat and 
 belly become of a paler red, the back more green, and the 
 glowing tints subside. 
 
 With respect to the courtship of fishes, other cases have 
 been observed since the first edition of this book appeared, 
 besides that already given of the stickleback. Mr. W. S. 
 Kent says that the male of the Labrus mixtus, which, as 
 we have seen, differs in color from the female, makes " a 
 deep hollow in the sand of the tank, and then endeavors in 
 the most persuasive manner to induce a female of the same 
 species to share it with him, swimming backward and for- 
 ward between her and the completed nest, and plainly 
 exhibiting the greatest anxiety for her to follow. The 
 males of Cantharus lineatus become, during the breeding- 
 
 * Yarrell, "British Fishes," vol. ii, 1836, pp. 10, 12, 35. 
 |W. Thompson, in "Annals and Mag. of Nat. History," vol. vi, 
 1841, p. 440. 
 
 J" The American Agriculturist," 1868, p. 100. 
 " Annals and Mag. of Nat. Hist.," Oct., 1852.
 
 FISHES. 387 
 
 season, of deep leaden-black; they then retire from the 
 shoal, and excavate a hollow as a nest. " Each male now 
 mounts vigilant guard over his respective hollow, and vig- 
 orously attacks and drives away any other fish of the same 
 sex. Toward his companions of the opposite sex his con- 
 duct is far different; many of the latter are now distended 
 with spawn, and these he endeavors by all the means in his 
 power to lure singly to his prepared hollow, and there to 
 deposit the myriad ova with which they are laden, which 
 he then protects and guards with the greatest care."* 
 
 A more striking case of courtship, as well as of display, 
 by the males of a Chinese Macropus has been given by M. 
 Carbonnier, who carefully observed these fishes under con- 
 finement, f The males are most beautifully colored, more 
 so than the females. During the breeding-season they con- 
 tend for the possession of the females ; and, in the act of 
 courtship, expand their fins, which are spotted and orna- 
 mented with brightly colored rays, in the same manner, 
 according to M. Carbonnier, as the peacock. They 
 then also bound about the females with much vivacity, and 
 appear by "1'etalage de leurs vives couleurs chercher a 
 attirer Fattention des femelles, lesquelles ne paraissaient 
 indifferentes a ce manege, elles nageaient avec une molle 
 lenteur vers les males et semblaient se complaire dans leur 
 voisinage." After the male has won his bride he makes a 
 little disk of froth by blowing air and mucus out of his 
 mouth. He then collects the fertilized ova dropped by the 
 female in his mouth; and this caused M. Carbonnier much 
 alarm, as he thought that they were going to be devoured. 
 But the male soon deposits them in the disk of froth, after- 
 ward guarding them, repairing the froth, and taking care 
 of the young when hatched. I mention these particulars 
 because, as we shall presently see, there are fishes the males 
 of which hatch their eggs in their mouths; and those who 
 do not believe in the principle of gradual evolution might 
 ask how could such a habit have originated; but the diffi- 
 culty is much diminished when we know that there are 
 fishes which thus collect and carry the eggs; for if delayed 
 by any cause in depositing them, the habit of hatching 
 them in their mouths might have been acquired. 
 
 * "Nature," May, 1873, p. 25. 
 
 f " Bull, de la Soc. d'Acclimat.," Paris, Juty, 1869, and Jan. 1870.
 
 388 THE DESCENT OF MAN. 
 
 To return to our more immediate subject. The case 
 Btands thus; female fishes, as far as I can learn, never will- 
 ingly spawn except in the presence of the males; and the 
 males never fertilize the ova except in the presence of the 
 females. The males fight for the possession of the females. 
 In many species the males while young resemble the females 
 in color; but when adult become much more brilliant, and 
 retain their colors throughout life. In other species the 
 males become brighter than the females and otherwise more 
 highly ornamented, only during the season of love. The 
 males sedulously court the females, and in one case, as we 
 have seen, take pains in displaying their beauty before 
 them. Can it be believed that they would thus act to no 
 purpose during their courtship? And this would be the case 
 unless the females exert some choice and select those males 
 which please or excite them most. If the female exerts 
 such choice, all the above facts on the ornamentation of 
 the males become at once intelligible by the aid of sexual 
 selection. 
 
 We have next to inquire whether this view of the bright 
 colors of certain male fishes having been acquired through 
 sexual selection can, through the law of the equal trans- 
 mission of characters to both sexes, be extended to those 
 groups in which the males and females are brilliant in the 
 same, or nearly the same, degree and manner. In such a 
 genus as Labrus, which includes some of the most splendid 
 fishes in the world for instance, the Peacock Labrus (L. 
 pavo], described,* with pardonable exaggeration, as formed 
 of polished scales of gold, incrusting lapis-lazuli, rubies, 
 sapphires, emeralds and amethysts we may, with much 
 probability, accept this belief, for we have seen that the 
 sexes in at least one species of the genus differ greatly in 
 color. With some fishes, as with many of the lowest ani- 
 mals, splendid colors may be the direct result of the nature 
 of their tissues and of the surrounding conditions, without 
 the aid of selection of any kind. The gold-fish (Cyprinus 
 auratus), judging from the analogy of the golden variety 
 of the common carp, is perhaps a case in point, as it may 
 owe its splendid colors to a single abrupt variation, due to 
 the conditions to which this fish has been subjected under 
 
 *Bory de Saint Vincent, in "Diet. Class. d'Hist. Nat.," torn. ix f 
 1826, p. 151.
 
 FISHES. 389 
 
 confinement. It is, however, more probable that these 
 colors have been intensified through artificial selection, as 
 this species has been carefully bred in China from a remote 
 period.* Under natural conditions it does not seem prob- 
 able that beings so highly organized as fishes, and which 
 live under such complex relations, should become brilliantly 
 colored without suffering some evil or receiving some bene- 
 fit from so great a change, and consequently without the 
 intervention of natural selection. 
 
 What, then, are we to conclude in regard to the many 
 fishes, both sexes of which are splendidly colored? Mr. 
 AVallace f believes that the species which frequent reefs, 
 where corals and other brightly-colored organisms abound, 
 are brightly colored in order to escape detection by their 
 enemies; but according to my recollection they were thus 
 rendered highly conspicuous. In the fresh waters of the 
 tropics there are no brilliantly-colored corals or other 
 organisms for the fishes to resemble; yet many species in 
 the Amazons are beautifully colored, and many of the car- 
 nivorous Cyprinidse in India are ornamented with " bright 
 longitudinal lines of various tints. "\ Mr. McClelland, in 
 describing these fishes, goes so far as to suppose that "the 
 peculiar brilliancy of their colors" serves as "a better 
 mark for king-fishers, terns, and other birds which are 
 destined to keep the number of these fishes in check;" but 
 at the present day few naturalists will admit that any 
 animal has been made conspicuous as an aid to its own 
 destruction. It is possible that certain fishes may have 
 been rendered conspicuous in order to warn birds and beasts 
 of prey that they were unpalatable, as explained when 
 treating of caterpillars; but it is not, I believe, known that 
 
 * Owing to some remarks on this subject made in my work " On 
 the Variation of Animals under Domestication," Mr. W. F. Mayers 
 ("Chinese Notes and Queries," Aug. 1868, p. 123) has searched the 
 ancient Chinese encyclopedias. He finds that gold-fish were first 
 reared in confinement during the Sung Dynasty which commenced 
 A. D. 960. In the year 1129 these fishes abounded. In another 
 place it is said that since the year 1548 there has been " produced at 
 Hangchow's a variety called the fire-fish, from its intensely red color. 
 It is universally admired and there is not a household where it is not 
 cultivated, in rivalry as to its color, and as a source of profit." 
 
 f " Westminster Review," July, 1867, p. 7. 
 
 J" Indian Cyprinidae," by Mr. M'CleUand, "Asiatic Researches," 
 . xix, part ii, 1839, p. 230.
 
 390 THE DESCENT OF MAN. 
 
 any fish, at least any fresh-water fish, is rejected from 
 being distasteful to fish-devouring animals. Ou the whole, 
 the most probable view in regard to the fishes, of which 
 both sexes are brilliantly colored, is that their colors were 
 acquired by the males as a sexual ornament, and were 
 transferred equally, or nearly so, to the other sex. 
 
 We have now to consider whether, when the male differs 
 in a marked manner from the female in color or in other 
 ornaments, he alone has been modified, the variations being 
 inherited by his male offspring alone ; or whether the 
 female has been specially modified and rendered inconspicu- 
 ous for the sake of protection, such modifications being 
 inherited only by the females. It is impossible to doubt 
 that color has been gained by many fishes as a protection; no 
 one can examine the speckled upper surface of a flounder 
 and overlook its resemblance to the sandy bed of the sea on 
 which it lives. Certain fishes, moreover, can through the 
 action of the nervous system change their colors in adapta- 
 tion to surrounding objects, and that within a short time.* 
 One of the most striking instances ever recorded of an 
 animal being protected by its color (as far as it can be 
 fudged of in preserved specimens), as well as by its form, 
 is that given by Dr. Gimtherf of a pipe-fish, which, with 
 its reddish streaming filaments, is hardly distinguishable 
 from the sea-weed to which its clings with its prehensile 
 tail. But the question now under consideration is whether 
 the females alone have been modified for this object. We 
 can see that one sex will not be modified through natural 
 selection for the sake of protection more than the other, 
 supposing both to vary, unless one sex is exposed for a 
 longer period to danger, or has less power of escaping from 
 such danger than the other; and it does not appear that 
 with fishes the sexes differ in these respects. As far as 
 there is any difference the males, from being generally 
 smaller and from wandering more about, are exposed to 
 greater danger than the females; and yet when the sexes 
 differ the males are almost always the more conspicuously 
 colored. The ova are fertilized immediately after being 
 deposited; and when this process lasts for several days, as 
 in the case of the salmon, t the female during the whole 
 
 *Q. Pouchet, L'Institut, Nov. 1, 1871, p. 184. 
 
 t " Proc. Zoolog. Soc.," 1865, p. 327, pi. xiv and xv. 
 
 j Yarrell, " British Fishes," vol. ii, p. 11.
 
 FISHES. 391 
 
 time is attended by the male. After the ova are fertilized 
 they are, in most cases, left unprotected by both parents, 
 so that the males and females, as far as oviposition is con- 
 cerned, are equally exposed to danger, and both are equally 
 important for the production of fertile ova; consequently 
 the more or less brightly colored individuals of either 
 sex would be equally liable to be destroyed or preserved, 
 and both would have an equal influence on the colors of 
 their offspring. 
 
 Certain fishes, belonging to several families, make nests, 
 and some of them take care of their young when hatched. 
 Both sexes of the bright- colored Crenildbrus mttssa and 
 melops work together in building their nests with sea- weed, 
 shells, etc.* But the males of certain fishes do all the 
 work and afterward take exclusive charge of the young. 
 This is the case with the dull-colored gobies, f in which the 
 sexes are not known to differ in color, and likewise with 
 the sticklebacks (Gasterosteus), in which the males become 
 brilliantly colored during the spawning season. The male 
 of the smooth-tailed stickleback ( 0. leiurus} performs the 
 duties of a nurse with exemplary care and vigilance during 
 a long time, and is continually employed in gently leading 
 back the young to the nest when they stray too far. He 
 courageously drives away all enemies, including the females 
 of his own species. It would indeed be no small relief to 
 the male if the female after depositing her eggs were 
 immediately devoured by some enemy, for he is forced 
 incessantly to drive her from the nest.J 
 
 The males of certain other fishes inhabiting South Amer- 
 ica and Ceylon, belonging to two distinct orders, have the 
 extraordinary habit of hatching within their mouths, or 
 branchial cavities, the eggs laid by the females. I am 
 informed by Prof. Agassiz that the males of the Amazonian 
 
 * According to the observations of M. Gerbe; see Giinther's 
 " Eecord of Zoolog. Literature," 1865, p. 194 
 
 tCuvie"r, " Regne Animal," vol. ii, 1829, p. 242. 
 
 \ See Mr. Warington's most interesting description of tlie habits of 
 the Gasterosteus leiurus in " Annals and Mag. of Nat. Hist.." Nov., 
 1855. 
 
 Prof. Wyman, in "Proc. Boston Soc. of Nat. Hist.," Sept. 15, 
 1857. Also Prof. Turner, in "Journal of Anatomy and Phys.," 
 Nov. 1, 1866, p. 78. Dr. Giinther has likewise described other
 
 392 THE DESCENT OF MAN. 
 
 species which follow this habit, ( ' not only are generally 
 brighter than the females, but the difference is greater at 
 the spawning-season than at any other time." The species 
 of Geophagus act in the same manner; and in this genus, a 
 conspicuous protuberance becomes developed on the fore- 
 head of the males during the breeding-season. With the 
 various species of Chromids, as Prof. Agassiz likewise 
 informs me, sexual differences in color may be observed, 
 " whether they lay their eggs in the water among aquatic 
 plants or deposit them in holes, leaving them to come out 
 without further care; or build shallow nests in the river 
 mud, over which they sit, as our Pomotis does. It ought 
 also to be observed that these sitters are among the bright- 
 est species in their respective families; for instance, Hygro- 
 gonus is bright green with large black ocelli, encircled 
 with the most brilliant red." Whether with all the species 
 of Chromids it is the male alone which sits on the eggs is 
 not known. It is, however, manifest that the fact of the 
 eggs being protected or unprotected by the parents, has had 
 little or no influence on the differences in color between the 
 sexes. It is further manifest in all the cases in which the 
 males take exclusive charge of the nests and young, that 
 the destruction of the brighter-colored males would be far 
 more influential on the character of the race than the 
 destruction of the brighter-colored females; for the death 
 of the male during the period of incubation or nursing 
 would entail the death of the young, so that they could not 
 inherit his peculiarities; yet in many of these very cases 
 the males are more conspicuously colored than the females. 
 In most of the Lophobranchii (Pipe-fish, Hippocampi, 
 etc.) the males have either marsupial sacks or hemispherical 
 depressions on the abdomen, in which the ova laid by the 
 female are hatched. The males also show great attachment 
 to their young.* The sexes do not commonly differ much 
 in color; but Dr. Giinther believes that the male Hippo- 
 campi are rather brighter than the females. The genus 
 Solenostoma, however, offers a curious exceptional case,f 
 for the female is much more vividly colored and spotted 
 
 * Yarrell, " Hist, of British Fishes," vol. ii, 1836, pp. 329, 338. 
 
 f Dr. Qiinther, since publishing an account of this species in " The 
 Fishes of Zanzibar," by Col. Play fair, 1866, p. 137, has re-examined 
 the specimens and has given rue the above information.
 
 FISHES. 393 
 
 than the male, and she alone has a marsupial sack and 
 hatches the eggs; so that the female of Solenostoma differs 
 from all the other Lophobranchii in this latter respect, and 
 from almost all other fishes, in being more brightly colored 
 than the male. It is improbable that this remarkable 
 double inversion of character 'in the female should be 
 an accidental coincidence. As the males of several fishes, 
 which take exclusive charge of the eggs and young, are 
 more brightly colored than the females, and as here the 
 female Solenostoma takes the same charge and is brighter 
 than the male, it might be argued that the conspicuous colors 
 of that sex which is the more important of the two for the 
 welfare of the offspring, must be in some manner pro- 
 tective. But from the large number of fishes, of which the 
 males are either permanently or periodically brighter than 
 the females, but whose life is not at all more important for 
 the welfare of the species than that of the female, this 
 view can hardly be maintained. "When we treat of birds 
 we shall meet with analogous cases, where there has been a 
 complete inversion of the usual attributes of the two sexes, 
 and we shall then give what appears to be the probable 
 explanation, namely, that the males have selected the more 
 attractive females, instead of the latter having selected, in 
 accordance with the usual rule throughout the animal 
 kingdom, the more attractive males. 
 
 On the whole we may conclude, that with most fishes, in 
 which the sexes differ in color or in other ornamental char- 
 acters, the males originally varied, with their variations 
 transmitted to the same sex, and accumulated through 
 sexual selection by attracting or exciting the females. In 
 many cases, however, such characters have been transferred, 
 either partially or completely, to the females. In other 
 cases, again, both sexes have been colored alike for the sake 
 of protection; but in no instance does it appear that the 
 female alone has had her colors or other characters specially 
 modified for this latter purpose. 
 
 . The-iast point which need be noticed is that fishes are 
 known to make various noises, some of which are described 
 as being musical. Dr. Dufosse, who has especially attended 
 to this subject, says that the sounds are voluntarily pro- 
 duced in several ways by different fishes; by the friction of 
 the pharyngeal bones by the vibration of certain muscles 
 attached to the swim-bladder, which serves as a resounding
 
 394 THE DESCENT OF MAN. 
 
 board and by the vibration of the intrinsic muscles of the 
 swim-bladder. By this latter means the Trigla produces 
 pure and long-drawn sounds which range over nearly an 
 octave. But the most interesting case for us is that of two 
 species of Ophidium, in which the males alone are provided 
 with a sound-producing apparatus, consisting of small mov- 
 able bones, with proper muscles, in connection with the 
 swim-bladder.* The drumming of the Umbrinas in the 
 European seas is said to be audible from a depth of twenty 
 fathoms; and the fisherman of Eochelle assert "that the 
 males alone make the noise during the spawning-time; and 
 that it is possible by imitating it to take them without 
 bait."f From this statement, and more especially from 
 the case of Ophidium, it is almost certain that in this, the 
 lowest class of the Vertebrata, as with so many insects and 
 spiders, sound-producing instruments have, at least in some 
 cases, been developed through sexual selection, as a means 
 for bringing the sexes together. 
 
 AMPHIBIANS. 
 
 Urodela. I will begin with the tailed amphibians. The 
 sexes of salamanders or newts often differ much both in 
 color and structure. In some species prehensile claws 
 are developed on the fore legs of the males during 
 the breeding-season; and at this season in the male Triton 
 palmipes the hind feet are provided with a swimming-web, 
 which is almost completely absorbed during the winter; so 
 that their feet then resemble those of the female. J This 
 structure no doubt aids the male in his eager search and 
 pursuit of the female. While courting her he rapidly 
 vibrates the end of his tail. With our common newts 
 (Triton punctatus and cristatus) a deep, much indented 
 crest is developed along the back and tail of the male 
 during the breeding- season, which disappears during the 
 
 * "Comptes Rendus." Tom. xlvi, 1858, p. 353. Tom. xlvii, 1858, 
 p. 916. Tom. liv, 1862, p. 393. The noise made by the Umbrinas 
 (Scicena aqutta), is said by some authors to be more like that of a 
 flute or organ, than drumming: Dr. Zouteveen, in the Dutch trans- 
 lation of this work (vol. ii, p. 36), gives some further particulars on 
 the sounds made by fishes. 
 
 f The Rev. C. Kingsley, in " Nature," May, 1870, p. 40. 
 
 ; Bell "History of British Reptiles," 2nd edit. 1849, pp. 156-159
 
 AMPHIBIANS. 395 
 
 winter. Mr. St. George Mivart informs me that it is not 
 furnished with muscles, and therefore cannot be used for 
 locomotion. As during the season of courtship it becomes 
 edged with bright colors, there can hardly be a doubt that 
 it is a masculine ornament. In many species the body. pre- 
 sents strongly contrasted, though lurid tints, and these 
 become more vivid during the breeding-season. The male, 
 for instance, of our common little newt (Triton punctatus) 
 is " brownish-gray above, passing into yellow beneath, 
 which in the spring becomes a rich bright orange, marked 
 everywhere with round dark spots." The edge of the crest 
 
 Fig. 32. Triton cristatus (half natural size, from Bell's " British Reptiles "). 
 Upper figure, male during the breeding-season; lower figure, female. 
 
 also is then tipped with bright red or violet. The female 
 is usually of a yellowish-brown color with scattered brown 
 dots, and the lower surface is often quite plain.* The 
 young are obscurely tinted. The ova are fertilized during 
 the act of deposition, and are not subsequently tended by 
 either parent. We may therefore conclude that the males 
 have acquired their strongly-marked colors and ornamental 
 appendages through sexual selection; these being transmit- 
 ted either to the male offspring alone, or to both sexes. 
 
 Anura or Batrachia. With many frogs and toads the 
 colors evidently serve as a protection, such as the bright 
 
 *Ben, "History of British Reptiles," 2d edit., 1849, pp. 146, 151.
 
 396 THE DESCENT OF MAN. 
 
 green tints of tree frogs and the obscure mottled shades of 
 many terrestrial species. The most conspicuously-colored 
 toad which lever saw, the Pliryniscusnigricans,* had the 
 whole upper surface of the body as black as ink, with the 
 soles of the feet and parts of the abdomen spotted with the 
 brightest vermilion. It crawled about the bare sandy or 
 open grassy plains of La Plata under a scorching sun, "and 
 could not fail to catch the eye of every passing creature. 
 These colors are probably beneficial by making this animal 
 known to all birds of prey as a nauseous mouthful. 
 
 In Nicaragua there is a little frog " dressed in a bright 
 livery of red and blue " which does not conceal itself like 
 most other species, but hops about during the daytime, and 
 Mr. Belt says f that as soon as he saw its happy sense of 
 security he felt sure that it was uneatable. After several 
 trials he succeeded in tempting a young duck to snatch up 
 a young one, but it was instantly rejected; and the duck 
 ' ( went about jerking its head as if trying to throw off some 
 unpleasant taste." 
 
 With respect to sexual differences of color Dr. Giinther 
 does not know of any striking instance either with frogs 
 or toads; yet he can often distinguish the male from the 
 female by the tints of the former being a little more intense. 
 Nor does he know of any striking difference in external 
 structure between the sexes, excepting the prominences which 
 become developed during the breeding-season on the front 
 legs of the male, by which he is enabled to hold the female. \ 
 It is surprising that these animals have not acquired more 
 strongly-marked sexual characters; for though cold-blooded 
 their passions are strong. Dr. Giinther informs me that he 
 has several times found an unfortunate female toad dead 
 and smothered from having been so closely embraced by 
 three or four males. Frogs have been observed by Prof. 
 Hoffman in Giessen fighting all day long during the breed- 
 ing season, and with so much violence that one had its body 
 ripped open. 
 
 * "Zoology of the Voyage of the 'Beagle,' " 1843. Bell, ibid, p. 
 49. 
 
 f " The Naturalist in Nicaragua," 1874, p. 321. 
 
 \ The male alone of the Bufo sikimmensii (Dr. Anderson, " Proc. 
 Zoolog. Soc.," 1871, p. 204) has two plate-like callosities on the 
 thorax and certain rugosities on the fingers, which perhaps subserve 
 the same end as the above mentioned prominences.
 
 REPTILES. 397 
 
 Frogs and toads offer one interesting sexual difference, 
 namely, in the musical powers possessed by the males; but 
 to speak of music, when applied to the discordant and 
 overwhelming sounds emitted by male bull-frogs and some 
 other species seems, according to our taste, a singularly 
 inappropriate expression. Nevertheless, certain frogs sing 
 in a decidedly pleasing manner. Near Rio Janeiro I used 
 often to sit in the evening to listen to a number of little 
 Hylae perched on blades of grass close to the water, which 
 sent forth sweet chirping notes in harmony. The various 
 sounds are emitted chiefly by the males during the breed- 
 ing-season, as in the case of the croaking of our common 
 frog.* In accordance with this fact the vocal organs of the 
 males are more highly developed than those of the females. 
 In some genera the males alone are provided with sacs 
 which open into the larynx, f For instance, in the edible 
 frog (Rana esculenta) "the sacs are peculiar to the males, 
 and become, when filled with air in the act of croaking, 
 large globular bladders, standing out one on each side of 
 the head near the corners of the mouth/' The croak of 
 the male is thus rendered exceedingly powerful; while that 
 of the female is only a slight groaning noise. J In the sev- 
 eral genera of the family the vocal organs differ considerably 
 in structure, and their development in all cases may be 
 attributed to sexual selection. 
 
 REPTILES. 
 
 Chelonia. Tortoises and turtles do not off er well-marked 
 sexual differences. In some species the tail of the male is 
 longer than that of the female. In some the plastron or 
 lower surface of the shell of the male is slightly concave in 
 relation to the back of the female. The male of the mud- 
 turtle of the United States ( Chrysemys pictd) has claws on 
 its front feet twice as long as those of the female; and 
 these are used when the sexes unite. With the huge 
 tortoise of the Galapagos Islands ( Testudo nigra) the males 
 
 * Bell, " History of British Reptiles," 1849, p. 93. 
 
 fj. Bishop, in "Todd's Cyclop, of Anat. and Phys.," vol. iv, p. 
 
 {Bell, ibid, pp. 113-114. , 
 
 Mr. C. J. Maynard, "The American Naturalist," Dec. 1869, p.
 
 398 THE DESCENT OF MAN. 
 
 are said to grow to a larger size than the females. During 
 the pairing season, and at no other time, the male utters a 
 hoarse, bellowing noise which can be heard at the distance 
 of more than a hundred yards; the female, on the other 
 hand, never uses her voice.* 
 
 With the Testudo elegans of India it is said " that the 
 combats of the males may be heard at some distance from 
 the noise they produce in butting against each other. "\ 
 
 Crocodilia. The sexes apparently do not differ in color; 
 nor do I know that the males fight together, though this 
 is probable, for some kinds make a prodigious display 
 before the females. BartramJ describes the male alligator 
 as striving to win the female by splashing and roaring in 
 the midst of a lagoon, "swollen to an extent ready to 
 burst, with its head and tail lifted up, he springs or twirls 
 round on the surface of the water like an Indian chief 
 rehearsing his feats of war." During the season of love a 
 musky odor is emitted by the submaxiliary glands of the 
 crocodile and pervades their haunts. 
 
 Ophidia. Dr. Gunther informs me that the males are 
 always smaller than the females, and generally have longer 
 and slenderer tails; but he knows of no other difference in 
 external structure. In regard to color, he can almost 
 always distinguish the male from the female by his more 
 strongly pronounced tints; thus the black zigzag baud on 
 the back of the male English viper is more distinctly 
 defined than in the female. The difference is much plainer 
 in the rattlesnakes of North America, the male of which, 
 as the keeper in the Zoological Gardens showed me, can at 
 once be distinguished from the female by having more 
 lurid yellow about its whole body. In S. Africa the 
 Bucephalus capensis presents an analogous difference, for 
 the female " is never so fully variegated with yellow on the 
 sides as the male. || The male of the Indian Dipsas cynodon, 
 
 * See my " Journal of Researches during the Voyage of the 
 'Beagle, '"1845, p. 384. 
 
 fDr. Gunther, " Reptiles of British India," 1864, p. 7. 
 \ " Travels through Carolina," etc., 1791, p. 128. 
 iOwcn, "Anatomy of Vertebrates," vol. i, 1866, p. 615. 
 (Sir Andrew Smith, " Zoolog. of S. Africa: Reptilia," 1849, pi. x.
 
 REPTILES. 399 
 
 on the other hand, is blackish-brown, with the belly partly 
 black, while the female is reddish or yellowish-olive, with 
 the belly either uniform yellowish or marbled with black. 
 In the Tragops dispar of the same country the male is 
 bright green and the female bronze colored.* No doubt 
 the colors of some snakes are protective,, as shown by the 
 green tints of tree-snakes and the various mottled shades 
 of the species which live in sandy places; but it is doubtful 
 whether the colors of many kinds, for instance of the 
 common English snake and viper, serve to conceal them; 
 and this is still more doubtful with the many foreign 
 species which are colored with extreme elegance. The 
 colors of certain species are very different in the adult and 
 young states, f 
 
 During the breeding-season the anal scent-glands of 
 snakes are in active function; J and so it is with the same 
 glands in lizards, and as we have seen with the submaxiliary 
 glands of crocodiles. As the males of most animals search 
 for the females, these odoriferous glands probably serve to 
 excite or charm the female, rather than to guide her to the 
 spot where the male may be found. Male snakes, though 
 appearing so sluggish, are amorous; for many have been 
 observed crowding round the same female, and even round 
 her dead body. They are not known to fight together from 
 rivalry. Their intellectual powers are higher than might 
 have been anticipated. In the Zoological Gardens they 
 soon learn not to strike at the iron bar with which their 
 cages are cleaned; and Dr. Keen, of Philadelphia, informs 
 me that some snakes which he kept learned after four or 
 five times to avoid a noose, with which they were at first 
 easily caught. An excellent observer in Ceylon, Mr. E. 
 Layard, saw a cobra thrust its head through a narrow hole 
 and swallow a, toad. " With this incumbrance he could 
 not withdraw himself; finding this, he reluctantly dis- 
 gorged the precious morsel, which began to move off; this 
 
 *Dr. A. Giintlier, "Reptiles of British India," Ray Soc., 1864, pp. 
 304, 308. 
 
 f Dr. Stoliczka, " Journal of Asiatic Soc. of Bengal," vol. xxxix, 
 1870, pp. 205, 211. 
 
 J Owen, " Anatomy of Vertebrates," vol. i, 1866, p. 615. 
 
 " Rambles in Ceylon," in " Annals and Mag. ol tfai. Hist.," 3d 
 series, vqi. ix, 1852, p. 333.
 
 400 THE DESCENT OF MAN. 
 
 was too much for snake philosophy to bear, and the toad 
 was again seized, and again was the snake, after violent 
 efforts to escape, compelled to part with its prey. This 
 time, however, a lesson had been learned, and the toad was 
 seized by one leg, withdrawn, and then swallowed in 
 triumph." 
 
 The keeper in the Zoological Gardens is positive that 
 certain snakes, for instance Crotalus and Python, distin- 
 guish him from all other persons. Cobras kept together in 
 the same cage apparently feel some attachment toward each 
 other.* 
 
 It does not* however, follow because snakes have some 
 reasoning power, strong passions and mutual affection, 
 that they should likewise be endowed with sufficient taste 
 to admire brilliant colors in their partners, so as to lead to 
 the adornment of the species through sexual selection. 
 Nevertheless, it is difficult to account in any other manner 
 for the extreme beauty of certain species; for instance, of 
 the coral-snakes of South America, which are of a rich red 
 with black and yellow transverse bands. I well remember 
 how much surprise I felt at the beauty of the first coral- 
 snake which I saw gliding across a path in Brazil. Snakes 
 colored in this peculiar manner, as Mr. Wallace states on 
 the authority of Dr. Grunther,f are found nowhere else in 
 the world except in South America, and here no less than 
 four genera occur. One of these, Elaps, is venomous; a 
 second and widely-distinct genus is doubtfully venomous, 
 and the two others are quite harmless. The species belong- 
 ing to these distinct genera inhabit the same districts, and 
 are so like each other that no one " but a naturalist would 
 distinguish the harmless from the poisonous kinds." Hence, 
 as Mr. Wallace believes, the innocuous kinds have proba- 
 bly acquired their colors as a protection, on the principle of 
 imitation; for they would naturally be thought dangerous 
 by their enemies. The cause, however, of the bright 
 colors of the venomous Elaps remains to be explained, and 
 this may perhaps be sexual selection. 
 
 Snakes produce other sounds besides hissing. The 
 deadly Ecliis carinata has on its sides some oblique rows of 
 scales of a peculiar structure with serrated edges ; and 
 
 *Dr. Giinther, " Reptiles of British India," 1864, p. 340. 
 f " Westminster Review," July 1, 1867, p. 33.
 
 REPTILES. 401 
 
 when this snake is excited these scales are rubbed against 
 each other, which produces "a, curious prolonged, almost 
 hissing sound. " * With respect to the rattling of the 
 rattlesnake, we have at last some definite information; for 
 Prof essor Aughey states, f that on two occassons, being him- 
 self unseen, he watched from a little distance a rattlesnake 
 coiled up with head erect, which continued to rattle at 
 short intervals for half an hour; and at last he saw another 
 snake approach, and when they met they paired. Hence 
 he is satisfied that one of the uses of the rattle is to bring 
 the sexes together. Unfortunately he did not ascertain 
 whether it was the male or the female which remained 
 stationary and called for the other. But it by no means 
 follows from the above fact that the rattle may not be of 
 use to these snakes in other ways, as a warning to animals 
 which would otherwise attack them. Nor can I quite dis- 
 believe the several accounts which have appeared of their 
 thus paralyzing their prey with fear. Some other snakes 
 also make a distinct noise by rapidly vibrating their tails 
 against the surrounding stalks of plants ; and I have 
 myself heard this in the case of a Trigonocephalus in South 
 America. 
 
 Lacertilia. The males of some, probably of many kinds 
 of lizards, fight together from rivalry. Thus the arboreal 
 Anolis cristatellus of South America is extremely pugna- 
 cious: " During the spring and early part of the summer, 
 two adult males rarely meet without a contest. On first 
 seeing one another, they nod their heads up and down 
 three or four times, and at the same time expanding the 
 frill or pouch beneath the throat; their eyes glisten with 
 rage, and after waving their tails from side to side for a 
 few seconds, as if to gather energy, they dart at each other 
 furiously, rolling over and over, and holding firmly with 
 their teeth. The conflict generally ends in one of the com- 
 batants losing his tail, which is often devoured by the 
 victor. " The male of this species is considerably larger 
 than the female;! and this, as far as Dr. Giinther has been 
 
 *Dr. Anderson, "Proc. Zoolog. Soc.," 1871, p. 196. 
 t " The American Naturalist/' 1873, p. 85. 
 
 | Mr. N. L. Austen kept these animals alive for a considerable 
 time; see ',' Land and Water," July, 1867, p. 9.
 
 402 THE DESCENT OF MAN. 
 
 able to ascertain, is the general rule with lizards of all kinds. 
 The male alone of the Cyrtodactyhis rubidus of the Anda- 
 man Islands possesses pre-anal pores; and these pores, judg- 
 ing from analogy, probably serve to emit an odor.* 
 
 The sexes often differ greatly in various external charac- 
 ters. The male of the above-mentioned Anolis is f umished 
 with a crest which runs along the back and tail, and 
 can be erected at pleasure ; but of this crest the 
 female does not exhibit a trace. In the Indian 
 CopJiotis ceylanica the female has a dorsal crest, though 
 much less developed than in the male; and so it is, as Dr. 
 Giinther informs me, with the 
 females of many Iguanas, 
 Chameleons and other lizards. 
 In some species, however, 
 the crest is equally developed 
 in both sexes, as in the Iguana 
 tuberculata. In the genus 
 Sitana, the males alone are 
 furnished with a large throat- 
 pouch (fig. 33), which can be 
 folded up like a fan, and is 
 Sitana minor. Male with colored blue, black and red; 
 but these splendid colors are 
 exhibited only during the pair- 
 ing-season. The female does not possess even a rudi- 
 ment of this appendage. In the Anolis cristatellus accord- 
 ing to Mr. Auster . the throat pouch, which is bright red 
 marbled with yellow, is present in the female, though in a 
 rudimental condition. Again, in certain other lizards, 
 both sexes are equally well provided with throat pouches. 
 Here we see with species belonging to the same group, as 
 in BO many previous cases, the same character either con- 
 fined to the males or more largely developed in them than 
 in the females, or again equally developed in both sexes. 
 The little lizards of the genus Draco, which glide through 
 the air on their rib-supported parachutes, and which in the 
 beauty of their colors baffle description, are furnished with 
 skinny appendages to the throat " like the wattles of gall- 
 inaceous birds." These become erected when the animal 
 
 * Stoliczka, " Journal of Asiatic Soc. of Bengal," vol. xxxiv, 1870, 
 p. 166.
 
 REPTILES. 403 
 
 is excited. They occur in both sexes, but are best devel- 
 oped when the male arrives at maturity, at which age the 
 middle appendage is sometimes twice as long as the head. 
 Most of the species likewise have a low crest running along 
 the neck; and this is much more developed in the full-grown 
 males than in the females or young males.* 
 
 A Chinese species is said to live in pairs during the 
 spring; "and if one is caught the other falls from the tree 
 to the ground, and allows itself to be captured with im- 
 punity/' I presume from despair, f 
 
 There are other and much more 
 remarkable differences between 
 the sexes of certain lizards. The 
 male of Ceratophora aspera bears 
 on the extremity of his snout an 
 appendage half as long as the head. 
 It is cylindrical, covered with 
 scales, flexible and apparently 
 capable of erection; in the female 
 it is quite rudimental. In a second 
 species of the same genus a ter- 
 minal scale forms a minute horn 
 on the summit of the flexible 
 appendage; and in a third species 
 
 n vt 1J i" (fi Q/(\ 44, V. l Fig. 34. Ceratophora Stoddartn. 
 6. Stoddarhl (fig. 34), the whole Upper figure, male; lower 
 appendage is converted into a horn, figure, female, 
 which is usually of a white color, 
 
 but assumes a purplish tint when the animal is excited. In 
 the adult male of this latter species the horn is half an inch 
 in length, but it is of quite minute size in the female and in 
 the young. These appendages, as. Dr. Giinther has 
 remarked to me, may be compared with the combs of gall- 
 inaceous birds, and apparently serve as ornaments. 
 
 In the genus Chameleon we come to the acme of differ- 
 ence between the sexes. The upper part of the skull of the 
 male C. Mfurcus (fig. 35), an inhabitant of Madagascar, is 
 produced into two great, solid, bony projections, covered 
 
 * All the foregoing statements and quotations in regard to Copho- 
 tis, Sitana and Draco, as well as the following facts in regard to 
 Ceratophora and Charnaeleon, are from Dr. Gtinther himself, or from 
 his magnificent work on the "Reptiles of British India," Ray Soc.. 
 1864, pp. 122, 130, 135. 
 
 fMr. Swlnhoe, "Proc. Zoolog. Soc.," 1870, p. 240.
 
 404 
 
 THE DESCENT OF MAN. 
 
 with scales like tne resT; of the head; and of this wonderful 
 modification of structure the female exhibits only a rudi- 
 ment. Again, in Chamceleo Owenii (fig. 36), from the 
 vest coast of Africa, the male bears on his snout and fore- 
 
 Pig. 85. Chanueleo bif urcus. Upper figure, male ; lower figure, female. 
 
 head three curious horns, of which the female has not a 
 trace. These horns consist of an excrescence of bone 
 covered with a smooth sheath, forming part of the general 
 integuments of the body, so that they are identical in 
 structure with those of a bull, goat, or other sheath-horned 
 ruminant. Although the three horns differ so much in 
 appearance from the two great prolongations of the skull
 
 REPTILES. 
 
 405 
 
 in O. Mfurcus, we can hardly doubt that they serve the 
 same general purpose in the economy of these two animals. 
 The first conjecture, which will occur to every one, is that 
 they are used by the males for fighting together; and as 
 these animals are very quarrelsome,* this is probably a cor- 
 rect view. Mr. T. W. Wood also informs me that he once 
 watched two individuals of C. pumilus fighting violently 
 on the branch of a tree; they flung their heads about and 
 tried to bite each other; they then rested for a time and 
 afterward continued their battle. 
 
 Pig. 36. Chamasleo Owenil. Upper figure, male; lower figure, female. 
 
 With many lizards the sexes differ slightly in color, the 
 tints and stripes of the males being brighter and more dis- 
 tinctly defined than in the females. This, for instance, is 
 the case with the above Cophotis and with the Acantlio- 
 dactylus capensis of S. Africa. In a Cordylus of the latter 
 country, the male is either much redder or greener than 
 the female. In the Indian Galotes nigrilabris there is a 
 still greater difference; the lips also of the male are black, 
 while those of the female are green. In our common little 
 viviparous lizard (Zootoca vivipara) " the under side of the 
 body and base of the tail in the male are bright orange, 
 
 *Dr. Bucholz, 
 
 78. * 
 
 Monatsberioht K. Preuss. Akad,," Jan,, 1874,
 
 406 THE DESCENT OF MAN. 
 
 spotted with black; in the female these parts are pale gray- 
 ish green without spots."* We have seen that the males 
 alone of Sitana possess a throat-pouch; and this is splen- 
 didly tinted with blue, black and red. In the Proctotretus 
 tenuis of Chili the male alone is marked with spots of blue, 
 green and coppery red. f In many cases the males retain 
 the same colors throughout the year, but in others they 
 become much brighter during the breeding-season; I may 
 give as an additional instance the Calotes maria, which at 
 this season has a bright red head, the rest of the body being 
 green. J 
 
 Both sexes of many species are beautifully colored exactly 
 alike; and there is no reason to suppose that such colors are 
 protective. No doubt with the bright-green kinds which 
 live in the midst of vegetation, this color serves to conceal 
 them; and in N. Patagonia I saw a lizard (Proctotretus 
 multimaculatus) which, when frightened, flattened its body, 
 closed its eyes, and then from its mottled tints was hardly 
 distinguishable from the surrounding sand. But the bright 
 colors with which so many lizards are ornamented, as well 
 as their various curious appendages, were probably acquired 
 by the males as an attraction, and then transmitted either 
 to their male offspring alone, or to both sexes. Sexual 
 selection, indeed, seems to have played almost as important 
 a part with reptiles as with birds; and the less conspicuous 
 colors of the females in comparison with the males cannot 
 be accounted for, as Mr. Wallace believes to be the case 
 with birds, by the greater exposure of the females to danger 
 during incubation. 
 
 *Bell, " History of British Reptiles," 2d edit., 1849, p. 40. 
 
 f For Proctotretus see "Zoology of the Voyage of the 'Beagle;' 
 Reptiles," by Mr. Bell, p. 8. For the lizards of S. Africa, see 
 " Zoology of S. Africa: Reptiles," by Sir Andrew Smith, pi. 25 and 
 39. For the Indian Calotes, see " Reptiles of British India," by Dr., 
 Giinther, p. 143. 
 
 JGuntherin "Proc. Zoolog. Soc.," 1870, p. 778, with a colored 
 figure.
 
 BIRDS. 407 
 
 CHAPTER XIII. 
 
 SECONDARY SEXUAL CHARACTERS OF BIRDS. 
 
 Sexual differences Law of battle Special weapons Vocal organs 
 Instrumental music Love-antics and dances Decorations, 
 permanent and seasonal Double and single annual moults 
 Display of ornaments by the males. 
 
 SECONDARY sexual characters are more diversified and 
 conspicuous in birds, though not perhaps entailing more 
 important changes of structure, than in any other class of 
 animals. I shall, therefore, treat the subject at consider- 
 able length. Male birds sometimes, though rarely, possess 
 special weapons for fighting with each other. They charm the 
 female by vocal or instrumental music of the most varied 
 kinds. They are ornamented by all sorts of combs, wattles, 
 protuberances, horns, air-distended sacks, top-knots, naked 
 shafts, plumes and lengthened feathers gracefully spring- 
 ing from all parts of the body. The beak and naked skin 
 about the head and the feathers are often gorgeously col- 
 ored. The males sometimes pay their court by dancing or 
 by fantastic antics performed either on the ground or in 
 the air. In one instance, at least, the male emits a musky 
 odor, which we may suppose serves to charm or excite the 
 female; for that excellent observer, Mr. Eamsay,* says of 
 the Australian musk duck (Biziura lobata) that "the 
 smell which the male emits during the summer months is 
 confined to that sex, and in some individuals is retained 
 throughout the year. I have never, even in the breeding- 
 season, shot a female which had any smell of musk." So 
 powerful is this odor during the pairing-season that it can 
 be detected long before the bird can be seen.f On the 
 whole, birds appear to be the most aesthetic of all animals, 
 excepting of course man, and they have nearly the same 
 
 * " Ibis," vol. iii (new series), 1867, p. 414. 
 
 4 Gould, "Hand-book to the Birds of Australia," 1865, vol. ii, p.
 
 408 THE DESCENT OF MAN, 
 
 taste for the beautiful 'as we have. This is shown by our 
 enjoyment of the singing of birds, and by our women, both 
 civilized and savage, decking their heads with borrowed 
 plumes and using gems which are hardly more brilliantly 
 colored than the naked skin and wattles of certain birds. 
 In man, however, when cultivated the sense of beauty is 
 manifestly a far more complex feeling and is associated 
 with various intellectual ideas. 
 
 Before treating of the sexual characters with which we 
 are here more particularly concerned, I may just allude to 
 certain differences between the sexes which apparently 
 depend on differences in their habits of life; for such 
 cases, though common in the lower, are rare in the higher 
 classes. Two humming - birds belonging to the genus 
 Eustephanus, which inhabit the Island of Juan Fernandez, 
 were long thought to be specifically distinct, but are 
 now known, as Mr. Gould informs me, to be the male 
 and female of the same species, and they differ slightly 
 in the form of the beak. In another genus of hum- 
 ming-birds ( Grypus] the beak of the male is serrated along 
 the margin and hooked at the extremity, thus differing 
 much from that of the female. In the Neomorpha of New 
 Zealand, there is, as we have seen, a still wider difference 
 in the form of the beak in relation to the manner of feed- 
 ing of the two sexes. Something of the same kind has 
 been observed with the goldfinch (Carduelis elegans), for I 
 am assured by Mr. Jcnner "Weir that the bird-catchers 
 can distinguish the males by their slightly longer beaks. 
 The flocks of males are often found feeding on the seeds of 
 the teazle (Dipsacus), which they can reach with their 
 elongated beaks, while the females more commonly feed on 
 the seeds of the betony or Scrophularia. With a slight 
 difference of this kind as a foundation we can see how the 
 beaks of the two sexes might be made to differ greatly 
 through natural selection. In some of the above cases, 
 however, it is possible that the beaks of the males may 
 have been first modified in relation to their contests with 
 other males; and that this afterward led to slightly changed 
 habits of life. 
 
 Law of Battle. Almost all male birds are extremely 
 pugnacious, using their beaks, wings, and legs for fighting 
 together. .We see this every spring with our robins and
 
 BIRDS. 409 
 
 sparrows. The smallest of all birds, namely, the humming- 
 bird, is one of the most quarrelsome. Mr. Gosse* describes 
 a battle in which a pair seized hold of each other's beaks, 
 and whirled round and round till they almost fell to the 
 ground; and M. Montes de Oca, in speaking of another 
 genus of humming-bird, says that two males rarely meet 
 without a fierce aerial encounter; when kept in cages " their 
 fighting has mostly ended in the splitting of the tongue of 
 one of the two, which then surely dies from being unable 
 to feed."f With Waders, the males of the common water- 
 hen (Gallinula chloropus) "when pairing, fight violently 
 for the females; they stand nearly upright in the water and 
 strike with their feet." Two were seen to be thus engaged 
 for half an hour, until one got hold of the head of the 
 other, which would have been killed had not the observer 
 interfered; the female all the time looking on as a quiet 
 spectator. \ Mr. Blyth informs me that the males of an 
 allied bird ( Gallicrex cristatus) are a third larger than the 
 females, and are so pugnacious during the breeding-season 
 that they are kept by the natives of Eastern Bengal for the 
 sake of fighting. Various other birds are kept in India for 
 the same purpose, for instance, the bulbuls (Pycnonotus 
 hcemorrhous) which " fight with great spirit." | 
 
 The polygamous ruff, Machetes pugnax (fig. 37), is 
 notorious for his extreme pugnacity; and in the spring, the 
 males, which are considerably larger than the females, .con- 
 gregate day after day at a particular spot, \vhere the females 
 propose to lay their eggs. The fowlers discover these spots 
 by the turf being trampled somewhat bare. Here they fight 
 very much like game-cocks, seizing each other with their 
 beaks and striking with their wings. The great ruff of 
 feathers round the neck is then erected, and according to 
 Col. Montagu " sweeps the ground as a shield to defend 
 the more tender parts;" and this is the only instance known 
 to me in the case of birds of any structure serving as a 
 shield. The ruff of feathers, however, from its varied and 
 
 * Quoted by Mr. Gould, "Introduction to the Trochilidae," 1861, 
 p. 29. 
 
 f Gould, ibid, p. 52. 
 
 j W. Thompson, " Nat Hist, of Ireland; Birds," vol. ii, 1850, p. 
 327. 
 
 Jerdon, "Birds of India," 1863, vol. ii, p. 96,
 
 410 
 
 THE DESCENT OF MAN, 
 
 rich colors probably serves in chief part as an ornament. 
 Like most pugnacious birds, they seem always ready to 
 
 fight, and when closely confined often kill each other; but 
 Montagu observed that their pugnacity becomes greater 
 during the spring, when the long feathers on their necks 
 are fully developed; and at this period the least movement
 
 BIRDS. 4H 
 
 by any one bird provokes a general battle.* Of the pug- 
 nacity of web-footed birds, two instances will suffice ; in 
 Guiana " bloody fights occur during the breeding-season 
 between the males of the wild musk-duck (Cairina mo- 
 schata) ; and where these fights have occurred the " river is 
 covered for some distance with feathers." f Birds which 
 seem ill-adapted for fighting engage in fierce conflicts; thus 
 the stronger males of the pelican drive away the weaker 
 ones, snapping with their huge beaks and giving heavy 
 blows with their wings. Male snipe fight together, "tug- 
 ging and pushing each other with their bills in the most 
 curious manner imaginable." Some few birds are believed 
 never to fight; this is the case, according to Audubon, with 
 one of the woodpeckers of the United States (Picu sau- 
 ratus), although " the hens are followed by even half a 
 dozen of their gay suitors." J 
 
 The males of many birds are larger than the females, 
 and this no doubt is the' result of the advantage gained by 
 the larger and stronger males over their rivals during many 
 generations. The difference in size between the two sexes 
 is carried to an extreme point in several Australian species; 
 thus the male musk-duck (Biziura) and the male Cinclor- 
 amplius cruralis (allied to our pipjs) are by measure- 
 ment actually twice as large as their respective females. 
 With many other birds the females are larger than the 
 males; and, as formerly remarked, the explanation often 
 given, namely, that the females have most of the work in 
 feeding their young, will not suffice. In some few cases, 
 as we shall hereafter see, the females apparently have 
 acquired their greater size and strength for the sake of con- 
 quering other females and obtaining possession of the 
 males. 
 
 The males of many gallinaceous birds, especially of the 
 polygamous kinds, are furnished with special weapons foi 
 fighting with their rivals, namely spurs, which can be used 
 
 * Macgillivray, "Hist. Brit. Birds," vol. iv, 1852, pp. 177-iSl. 
 
 fSir R. Schomburgk, in " Journal of R. Geograph. Soc.," vol. xiii, 
 1843, p. 81. 
 
 | " Ornithological Biography," vol. i, p. 191. For pelicans and 
 snipes, see vol. iii, pp. 138, 477. 
 
 jGould, "Hand-book of Birds of Australia," vol. i, p. 395; vol. ii,
 
 412 THE DESCENT OF MAN. 
 
 with fearful effect. It has been recorded by a trustworthy 
 writer* that in Derbyshire a kite struck at a game-hen 
 accompanied by her chickens, when the cock rushed to the 
 fescue, and drove his spur right through the eye and skull 
 of the aggressor. The spur was with difficulty drawn from 
 the skull, jpd as the kite, though dead, retained his grasp, 
 the two birds were firmly locked together ; but the cock 
 when disentangled was very little injured. The invincible 
 courage of the game-cock is notorious ; a gentleman who 
 long ago witnessed the brutal scene, told me that a bird 
 had both its legs broken by some accident in the cock-pit, 
 and the owner laid a wager that if the legs could be spliced 
 so that the bird could stand upright, he would continue 
 fighting. This was effected on the spot, and the bird 
 fought with undaunted courage until he received his death- 
 stroke. In Ceylon a closely allied, wild species, the Gallus 
 Staiileyi, is known to fight desperately " in defense of his 
 seraglio," so that one of the combatants is frequently found 
 dead.f An Indian partridge (Ortygornis gularis), the 
 male of which is furnished with strong and sharp spurs, is 
 so quarrelsome " that the scars of former fights disfigure 
 the breast of almost every bird you kill."J 
 
 The males of alriaost all gallinaceous birds, even those 
 which are not furnished with spurs, engage during the 
 breeding-season in fierce conflicts. The Capercailzie and 
 Black-cock (Tetrao urogallus and T. tetrix) which are 
 both polygamists, have regular appointed places, where 
 during many weeks they congregate in numbers to fight 
 together and to display their charms before the females. 
 Dr. W. Kovalevsky informs me that in Russia he has seen 
 the snow all bloody on the arenas where the capercailzie 
 have fought; and the black-cocks " make the feathers fly 
 in every direction," when several " engage in a battle 
 royal." The elder Brehm gives a curious account of the 
 Balz, as the love-dances and love-songs of the black-cock 
 are called in Germany. The bird utters almost contin- 
 uously the strangest noises: "he holds his tail up and 
 spreads it out like a fan, he lifts up his head and neck with 
 all the feathers erect, and stretches his wings from the 
 
 *Mr. Hewitt in the "Poultry Book by Tegetmeier," 1866, p. 137. 
 f Layard, " Annals and Mag. of Nat. Hist.," vol. xiv, 1854, p. 63- 
 | Jerdon, "Birds of India," vol. iii, p. 574.
 
 BIRDS. 413 
 
 body. Then he takes a few jumps in different direc- 
 tions, sometimes in a circle, and presses the under part 
 of his beak so hard against the ground that the 
 chin feathers are rubbed off. During these move- 
 ments he beats his wings and turns round and 
 round. The more ardent he grows the more lively he 
 becomes, until at last the bird appears like a frantic creat- 
 ure." At such times the black-cocks are so absorbed that 
 they become almost blind and deaf, but less so than the 
 capercailzie; hence bird after bird may be shot on the same 
 spot, or even caught by the hand. After performing these 
 antics the males begin to fight; and the same black-cock, 
 in order to prove his strength over several antagonists, will 
 visit in the course of one morning several Balz-places, which 
 remain the same during successive years.* 
 
 The peacock with his long train appears more like a 
 dandy than a warrior, but he sometimes engages in fierce 
 contests; the Rev. W. Darwin Fox informs me that at some 
 little distance from Chester two peacocks became so excited 
 while fighting that they flew over the whole city, still 
 engaged, until they alighted on the top of St. John's tower. 
 
 The spur, in those gallinaceous birds which are thus pro- 
 vided, is generally single; but Polyplectron (see fig. 51) 
 has two or more on each leg; and one of the blood-pheas- 
 ants (Ithaginis criientus) has been seen with five spurs. 
 The spurs are generally confined to the male, being repre- 
 sented by mere knobs or rudiments in the female; but the 
 females of the Java peacock (Pavo muticus) and, as I am 
 informed by Mr. Blyth, of the small fire-backed pheasant 
 ( Euplocamus erythropthalmus) possess spurs. In Gralloper- 
 dix it is usual for the males to have two spurs, and for the 
 females to have only one on each leg. f Hence spurs may 
 be considered as a masculine structure, which has been 
 occasionally more or less transferred to the females. Like 
 most other secondary sexual characters, the spurs are highly 
 variable, both in number and development, in the same 
 species. 
 
 Various birds have spurs on their wings. But the Egyp- 
 
 *Brelim, " Illust. Thierleben," 1867, B. iv, s. 351. Some of the 
 foregoing statements are taken from L. Lloyd, " The Game Birds of 
 Sweden," etc., 1867, p. 79. 
 
 f Jerdon, " Birds of India," on Ithaginis, vol. iii, p. 523; on Gallo- 
 perdix, p. 541.
 
 414 THE DESCENT OF MAN. 
 
 tian goose (Cktitoalopex cegyptiacus) has only "bare obtuse 
 knobs," and these probably show us the first steps by which 
 true spurs have been developed in other species. In the 
 spur-winged goose (Plectropterus gamlensis) the males 
 have much larger spurs than the females; and they use 
 them, as I am informed by Mr. Bartlett, in fighting to- 
 gether, so that, in this case, the wing-spurs serve as sexual 
 ^weapons ; but according to Livingstone, they are chiefly 
 used in the defense of the young. The Palamedea (fig. 38) 
 is armed with a pair of spurs on each wing; and these are 
 such formidable weapons that a single blow has been known 
 to drive a dog howling away. But it does not appear that 
 the spurs in this case, or in that of some of the spur- 
 winged rails, are larger in the male than in the female.* 
 In certain plovers, however, the wing-spurs must be con- 
 sidered as a sexual character. Thus in the male of our 
 common peewit ( Vanellus cristatus) the tubercle on the 
 shoulder of the wing becomes more prominent during the 
 breeding-season, and the males fight together. In some 
 species of Lobivauellus a similar tubercle becomes developed 
 during the breeding-season " into a short, horny spur." In 
 the Australian L. lobatus both sexes have spurs, but these 
 are much larger in the males than in the females. In an 
 allied bird, the Hoplopterus armatus, the spurs do not in- 
 crease in size during the breeding-season; but these birds 
 have been seen in Egypt to fight together, in the same man- 
 ner as our peewits, by turning suddenly in the air and 
 striking sideways at each other, sometimes with fatal results. 
 Thus also they drive away other enemies, f 
 
 The season of love is that of battle; but the males of 
 some birds, as of the game-fowl and ruff, and even the 
 young males of the wild turkey and grouse^ are ready to 
 
 *For the Egyptian goose, see Macgillivray, "British Birds," vol 
 iv, p. 639. For Plectropterus, " Livingstone's Travels," p. 254. 
 For Palamedea, Brehm's "Thierleben," B. iv, s. 740. See also on 
 this bird Azara, "Voyages dans 1'Arnerique merid.," torn, iv, 1809, 
 pp. 179, 253. 
 
 fSee, on our peewit, Mr. R. Carr in "Land and Water," Aug. 8, 
 1868, p. 46. In regard to Lobivanellus, see Jerdon's " Birds of 
 India," vol. iii. p. 647, and Gould's "Hand-book of Birds of Austra- 
 lia," vol. ii, p. 220. For the Holopterus, see Mr. Allen in the 
 " Ibis," vol. v, 1863. p. 156. 
 
 \ Audubon, "Ornith. Biography," vol. ii, p. 492; vol. i, pp. 4-13.
 
 BIRDS, 15 
 
 fight whenever they meet. The presence of the female is 
 
 
 
 Pig. 88, Palamedea cornuta (from Brehm), showing the double wing-spurs and 
 the filament on 
 
 the teterrjima belli causa. The Bengali baboos make the 
 pretty little males of the amadavat (Estrelda amandavd)
 
 416 THE DESCENT OF MAN. 
 
 fight together by placing three small cages in a row with a 
 female in the middle: after a little time the two males are 
 turned loose and immediately a desperate battle ensues.* 
 When many males congregate at the same appointed spot 
 and fight together, as in the case of grouse and various 
 other birds, they are generally attended by the females, f 
 which afterward pair with the victorious combatants. But 
 in some cases the pairing precedes instead of succeeding 
 the combat; thus according to Audubon,J several males of 
 the Virginian goat -sucker (Caprimulgus virginianus) 
 " court in a highly entertaining manner the female, and 
 no sooner has she made her choice than her approved gives 
 chase to all intruders, and drives them beyond his 
 dominions." Generally the males try to drive away or kill 
 their rivals before they pair. It does not, however, appear 
 that the females invariably prefer the victorious males. I 
 have indeed been assured by Dr. W. Kovalevsky that the 
 female capercailzie sometimes steals away with a young 
 male who has not dared to enter the arena with the older 
 cocks, in the same manner as occasionally happens with the 
 does of the red-deer in Scotland. When two males contend 
 in presence of a single female, the victor, no doubt, com- 
 monly gains his desire; but some of these battles are caused 
 by wandering males trying to distract the peace of an 
 already mated pair. 
 
 Even with the most pugnacious species it is probable that 
 the pairing does not depend exclusively on the mere 
 strength and courage of the male: for such males are 
 generally decorated with various ornaments, which often 
 become more brilliant during the breeding - season, and 
 which are sedulously displayed before the females. The 
 
 *Mr. Blyth. " Land and Water." 1867, p. 212. 
 
 f Richardson on Tetrao umbellus " Fauna Bor. Amer. : Birds,* 
 1831.. p. 343. L. Lloyd, " Game Birds of Sweden," 1867, pp. 22, 79, 
 on the capercailzie and black-cock Brehin, however, asserts 
 ("Thierleben," etc., B. iv, s. 352) that in Germany the gray-hens do 
 not generally attend the Balzen of the black-cocks, but this is 
 an exception to the common rule; possibly the hens may lie hidden 
 in the surrounding bushes, as is known to be the case with the gray- 
 hens in Scandinavia, and with other species in North America. 
 
 t " Ornithological Biography," vol. ii. p. 275. 
 
 KBrehm, "Thierleben," etc., B iv, 1867, p. 990. Audubc0, 
 " Ornith. Biography,'' vol ii, p, 492. 
 
 *
 
 BIRDS. 417 
 
 males also endeavor to charm or excite their mates by love- 
 notes, songs and antics ; and the courtship is, in many 
 instances, a prolonged affair. Hence, it is not probable 
 that the females are indifferent to the charms of the oppo- 
 site sex, or that they are invariably compelled to yield to 
 the victorious males. It is more probable that the females 
 are excited, either before or after the conflict, by certain 
 males, and thins unconsciously prefer them. In the case of 
 Tetrao umbellus, a good observer * goes so far as to believe 
 that the battles of the males "are all a sham, performed to 
 show themselves to the greatest advantage before the 
 admiring females who assemble around; for I have never 
 been able to find a maimed hero, and seldom more than a 
 broken feather." I shall have to recur to this subject, but 
 I may here add that with the Tetrao cupido of the United 
 States, about a score of males assemble at a particular spot, 
 and, strutting about, make the whole air resound with 
 their extraordinary noises. At the first answer from a 
 female the males begin to fight furiously, and the weaker 
 give way; but then, according to Audubon, both the victors 
 and vanquished search for the female, so that the females 
 must either then exert a choice, or the battle must be 
 renewed. So, again, with one of the field-starlings of the 
 United States (Sturnella ludoviciana) the males engage in 
 fierce conflicts, " but at the sight of a female they all fly 
 after her as if mad." f 
 
 Vocal and Instrumental Music. With birds the voice 
 serves to express various emotions, such as distress, fear, 
 anger, triumph, or mere happiness. It is apparently 
 sometimes used to excite terror, as in the case of the 
 hissing noise made by some nestlings-birds. Audubon J 
 relates that a night-heron (Ardea nycticorax, Linn.) which 
 he kept tame, used to hide itself when a cat approached, 
 and then " suddenly start up uttering one of the most 
 frightful cries, apparently enjoying the cat's alarm and 
 flight." The common domestic cock clucks to the hen, 
 and the hen to her chickens, when a dainty morsel is 
 
 * " Land and Water." July 25, 1868. p. 14. 
 
 f Audubon's " Ornitholog. Biography;" on Tetrao cupido, vol. ii, 
 p. 492; on the Sturnus, vol. ii, p. 219. 
 
 \ " Ornithological Biograph.," vol. v, p. 601.
 
 418 THE DESCENT OF MAN. 
 
 found. The hen, when she has laid an egg, " repeats the 
 same note very often, and concludes with the sixth above, 
 which she holds for a longer time;"* and thus she expresses 
 her joy. Some social birds apparently call to each other 
 for aid; and as they flit from tree to tree the flock is kept 
 together by chirp answering chirp. During the nocturnal 
 migrations of geese and other water-fowl sonorous clangs 
 from the van may be heard in the darkness overhead, 
 answered by clangs in the rear. Certain cries serve as 
 danger signals, which, as the sportsman knows to his cost, 
 are understood by the same species and by others. The 
 domestic cock crows, and the humming-bird chirps in 
 triumph over a defeated rival. The true song, however, of 
 most birds and various strange cries are chiefly uttered 
 during the breeding-season, and serve as a charm, or merely 
 as a call-note to the other sex. 
 
 Naturalists are much divided with respect to the object 
 of the singing of birds. Few more careful observers ever 
 lived than Montagu, and he maintained that the " males 
 of song-birds and of many others do not in general search 
 for the female, but on the contrary, their business in the 
 spring is to perch on some conspicuous spot, breathing out 
 their full and amorous notes, which, by instinct, the female 
 knows, and repairs to the spot to choose her mate."f Mr. 
 Jenner Weir informs me that this is certainly the case with 
 the nightingale. Bechstein, who kept birds during his 
 whole life, asserts " that the female canary always chooses 
 the best singer, and that in a state of nature the female 
 finch selects that male out of a hundred whose notes please 
 her most.";); There can be no doubt that birds closely 
 attend to each other's song. Mr. Weir has told me of the 
 case of a bullfinch which had been taught to pipe a German 
 waltz, and who was so good a performer that he cost ten 
 guineas; when this bird was first introduced into a room 
 where other birds were kept and he began to sing, all the 
 others, consisting of about twenty linnets and canaries, 
 
 *The Hon. Daines Barrington, " Philosoph. Transact.," 1773, p. 252. 
 
 f" Ornithological Dictionary," 1833, p. 475. 
 
 $ " Naturgeschichte der Stul)rnvogel," 1840, s. 4. Mr. Harrison 
 Weir likewise writes to ine: "I am informed that the best singing 
 males generally get a mate first, when they are bred in the same 
 "
 
 BIRDS. 419 
 
 ranged themselves on the nearest side of their cages and list- 
 ened with the greatest interest to the new performer. Many 
 naturalists believe that the singing of birds is almost ex- 
 clusively " the effect of rivalry and emulation," and not 
 for the sake of charming their mates. This was the 
 opinion of Daines Barrington and White of Selborne, who 
 both especially attended to this subject.* Barrington, 
 however, admits that "superiority in song gives to birds an 
 amazing ascendency over others, as is well known to bird- 
 catchers." 
 
 It is certain that there is an intense degree of rivalry 
 between the males in their singing. Bird fanciers match 
 their birds to see which will sing longest; and I was told 
 by Mr. Yarrell that a first-rate bird will sometimes sing 
 till he drops down almost dead, or according to Bechstein,f 
 quite dead from rupturing a vessel in the lungs. What- 
 ever the cause may be, male birds, as I hear from Mr. 
 Weir, often die suddenly during the season of song. That 
 the habit of singing is sometimes quite independent of love 
 is clear, for a sterile, hybrid canary-bird has been described}: 
 as singing while viewing itself in a mirror and then dash- 
 ing at its own image ; it likewise attacked with fury 
 a female canary when put into the same cage. The 
 jealousy excited by the act of singing is constantly taken 
 advantage of by bird-catchers; a male, in good song, is 
 hidden and protected, while a stuffed bird surrounded by 
 limed twigs is expose to view. In this manner, as Mr. 
 Weir informs me, a man has in the course of a single day 
 caught fifty, and in one instance seventy male chaffinches. 
 The poAver and inclination to sing differ so greatly with birds 
 that although the price of an ordinary male chaffinch is only 
 sixpence, Mr. Weir saw one bird for which the bird-catcher 
 asked three pounds ; the test of a really good singer being 
 that it will continue to sing while the cage is swung round 
 the owner's head. 
 
 That male birds should sing from emulation as well as 
 for charming the female is not at all incompatible; and it 
 might have been expected that these two habits would 
 
 * "Philosophical Transactions," 1773, p. 263. White's " Natural 
 History of Selborne," 1825, vol. i, p. 246. 
 
 f " Naturgesch. der Stubenvogel," 1840, s. 252. 
 $Mr. Bold, "Zoologist," 1843-44, p. 659.
 
 420 THE DESCENT OF MAN. 
 
 have occurred, like those of display and pugnacity. Some 
 authors, however, argue that the song of the male cannot 
 serve to charm the female, because the females of some 
 few species, such as of the canary, robin, lark and bull- 
 finch, especially when in a state of widowhood, as Bech- 
 stein remarks, pour forth fairly melodious strains. In 
 some of these cases the habit of singing may be in part 
 attributed to the females having been highly fed and con- 
 fined,* for this disturbs all the usual functions connected 
 with the reproduction of the species. Many instances 
 have already been given of the partial transference of sec- 
 ondary masculine characters to the females, so that it is 
 not at all surprising that the females of some species should 
 possess the power of song. It has also been argued that 
 the song of the male cannot serve as a charm, because the 
 males of certain species, for instance of the robin, sing 
 during the autumn, f But nothing is more common than 
 for animals to take pleasure in practicing whatever instinct 
 they follow at other times for some real good. How often 
 do we see birds which fly easily gliding and sailing through 
 the air obviously for pleasure.'' The cat plays with the 
 captured mouse and the cormorant with the captured fish. 
 The weaver-bird (Ploceus), when confined in a cage, 
 amuses itself by neatly weaving blades of grass between the 
 wires of its cage. Birds which habitually fight during the 
 breeding-season are generally ready to fight at all times; 
 and the males of the capercailzie sometimes hold their 
 Balzen or leks at the usual place of assemblage during the 
 autumn. J Hence it is not at all surprising that male birds 
 should continue singing for their own amusement after the 
 season for courtship is over. 
 
 As shown in a previous chapter, singing is to a certain 
 extent an art, and is much improved by practice. Birds 
 can be taught various tunes, and even the unmelodious 
 sparrow has learned to sing like a linnet. They acquire 
 the song of their foster parents, and sometimes that of 
 
 *D. Barrington, "Phil. Transact.," 1773, p. 262. Bechstein. 
 " StubenvOgel," 1840, s. 4. 
 
 f This is likewise the case with the water-ouzel; see Mr. Hepburn 
 in the " Zoologist," 1845-46, p. 1068. 
 
 J L. Lloyd, " Game Birds of Sweden," 1867, p. 25. 
 
 Barrington, ibid, p. 264, Bechstein, ibid, s. 5.
 
 BIRDS. 421 
 
 their neighbors.* All the common songsters belong to the 
 Order of Insessores, and their vocal organs are much more 
 complex than those of most other birds; yet it is a singular 
 fact that some of the Insessores, such as ravens, crows, and 
 magpies, possess the proper apparatus,! though they never 
 eing, and do not naturally modulate their voices to any 
 great extent. Hunter asserts J that with the true songsters 
 the muscles of the larynx are stronger in the males than in 
 the females ; but with this slight exception there is no dif- 
 ference in she vocal organs of the two sexes, although the 
 males of most species sing so much better and more con- 
 tinuously than the females. 
 
 It is remarkable that only small birds properly sing. 
 The Australian genus Menura, however, must be excepted; 
 for the Menura Alberti, which is about the size of a half- 
 grown turkey, not only mocks other birds, but " its own 
 whistle is exceedingly beautiful and varied." The males 
 congregate and form " corroborying^ places," where they 
 sing, raising and spreading their tails like peacocks, and 
 drooping their wings. It is also remarkable that birds 
 which sing well are rarely decorated with brilliant colors 
 or other ornaments. Of our British birds, excepting the 
 bullfinch and goldfinch, the best songsters are plain- 
 colored. The kingfisher, bee-eater, roller, hoopoe, wood- 
 peckers, etc., utter harsh cries; and the brilliant birds of 
 the tropics are hardly ever songsters. || Hence bright 
 colors and the power of song seem to replace each other. 
 We can perceive that if the plumage did not vary in 
 brightness, or if bright colors were dangerous to the 
 species, other means would be employed to charm the 
 females; and melody of voice offers one such means. 
 
 In some birds the vocal organs differ greatly in the two', 
 
 * Bureau de la Malle gives a curious instance (" Annales des Sc. 
 Nat.," 3d series, Zoolog., torn, x, p. 118) of some wild blackbirds in 
 his garden in Paris, which, naturally learned a republican air from a 
 caged bird. 
 
 f Bishop, in "Todd's Cyclop, of Anat. and Phys.," vol. iv, p. 1496. 
 
 J As stated by Barrington in " Philosoph. Transact.," 1773, p. 262. 
 
 Gould, "Hand-book to the Birds of Australia," vol. i, 1865, pp. 
 308-310. See also Mr. T. W. Wood in the " Student," April, 1870, 
 p. 125. 
 
 fl See remarks to this effect in Gould's ' Introduction to the Tro> 
 chilidse," 1861, p. 22.
 
 422 
 
 THE DESCENT OF MAN. 
 
 In the Tefrao cupido (fig 39) the male lias two 
 bare, orange-colored sacks, one on each side of the neck ; 
 and these are largely inflated when the male, during the 
 breeding-season, makes his curious hollow sound, audible 
 at a great distance. Audubon proved that the sound was 
 
 intimately connected with this apparatus (which reminds 
 us of the air-sacks on each side of the mouth of cer- 
 tain male frogs), for he found that the sound was 
 much diminished when one of the sacks of a tame 
 bird was pricked, and when both were pricked it
 
 BIRDS. 423 
 
 was altogether stopped. The female has "a some- 
 what similar, though smaller naked space of skin 
 on the neck ; but this is not capable of inflation."* 
 The male of another kind of grouse (Tetrao urophasianus), 
 while courting the female, has his " bare yellow oesophagus 
 inflated to a prodigious size, fully half as large as the body;" 
 and he then utters various grating, deep, hollow tones. 
 With his neck-feathers erect, his wings lowered, and buzz- 
 ing on the ground, and his long pointed tail spread out 
 like a fan, he displays a variety of grotesque attitudes. The 
 oesophagus of the female is not in any way remarkable, f 
 
 It seems now well made out that the great throat-pouch 
 of the European male bustard (Otis tar da), and of at least 
 four other species, does not, as was formerly supposed, serve 
 to hold water, but is connected with the utterance during 
 the breeding-season of a peculiar sound resembling " oak."f 
 A crow-like bird inhabiting South America, Cephalopterus 
 ornatus (fig. 40), is called the umbrella-bird from its im- 
 mense top-knot, formed of bare white quills surmounted by 
 dark-blue plumes, which it can elevate into a great dome 
 no less than five inches in diameter, covering the whole 
 head. This bird has on its neck a long, thin, cylindrical, 
 fleshy appendage, which is thickly clothed with scale-like 
 blue feathers. It probably serves in part as an ornament, 
 but likewise as a resounding apparatus; for Mr. Bates found 
 that it is connected " with an unusual development of the 
 trachea and vocal organs." It is dilated when the bird, 
 utters its singularly deep, loud and long-sustained fluty 
 
 *"The Sportsman and Naturalist in Canada," by Maj. W. Ross 
 King, 1866, pp. 144-146. Mr. T. W. Wood gives in the " Student" 
 (April, 1870, p. 116) an excellent account of the attitude and habits 
 of this bird during its courtship. He states that the ear-tufts or 
 neck-plumes are erected so that they meet over the crown of the 
 head. See his drawing, fig. 39. 
 
 f Richardson, "Fauna Bor. American: Birds," 1831, p. 359, Audu- 
 bon, ibid, vol. iv, p. 507. 
 
 \ The following papers have been lately written on this subject: 
 Prof. A. Newton in the " Ibis," 1862, p. 107; Dr. Cullen, ibid, 1865, 
 
 S145; Mr. Flower in "Proc. Zool. Soc.," 1865, p. 747; and Dr. 
 urie in "Proc. Zool. Soc.," 1868, p. 471. In this latter paper an 
 excellent figure is given of the male Australian bustard in full dis- 
 play with the sack distended. It is a singular fact that the sack is 
 not developed in all the males of the same species.
 
 424 
 
 THE DESCENT OF MAN. 
 
 note. The head-crest and neck-appendage are rudimentary 
 in the female.* 
 
 The vocal organs of various web-footed and wading birds 
 are extraordinarily complex, and differ to a certain extent 
 in the two sexes. In some cases the trachea is convoluted, 
 
 Tig. 40. The Umbrella-bird or Cephalopterus ornatus, male (from Brehm). 
 
 like a French horn, and is deeply embedded in the sternum. 
 In the wild swan (Cygnus ferus) it is more deeply 
 embedded in the adult male than in the adult female or 
 
 * Bates, " The Naturalist on the Amazons," 1863, vol. ii, p. 284; 
 Wallace, in " Proc. Zool. Soc.," 1850, p. 206. A new species, with 
 a still larger neck appendage ((J. penduliger), has lately been dis- 
 covered, see "Ibis," voL i, p. 457.
 
 BIRDS. 425 
 
 young male. In the male Merganser the enlarged portion 
 of the trachea is furnished with an additional pair of mus- 
 cles.* In one of the ducks, however, namely, Anas 
 pundata, the bony enlargement is only a little more devel- 
 oped in the male than in the female, f But the meaning 
 of these differences in the trachea of the two sexes of the 
 Anatidse is not understood ; for the male is not always the 
 more vociferous; thus with the common duck, the male 
 hisses, while the female utters a loud quack. J In both 
 sexes of one of the cranes (Grus virgo] the trachea pene- 
 trates the sternum, but presents " certain sexual modifica- 
 tions." In the male of the black stork there is also a well- 
 marked sexual difference in the length and curvature of the 
 bronchi. Highly important structures have, therefore, in 
 bhese cases been modified according to sex. 
 
 It is often difficult to conjecture whether the many 
 strange cries and notes uttered by male birds during the 
 breeding-season serve as a charm or merely as a call to the 
 female. The soft cooing of the turtle-dove and of many 
 pigeons, it may be presumed, pleases the female. When the 
 female of the wild turkey utters her call in the morning, the 
 male answers by a note which differs from the gobbling 
 noise made, when with erected feathers, rustling wings and 
 distended wattles, he puffs and struts before her. || The 
 spel of the black-cock certainly serves as a call to the 
 female, for it has been known to bring four or five females 
 from a distance to a male under confinement; but as the 
 black-cock continues his spel for hours during successive 
 days, and in the case of the capercailzie ' ' with an agony 
 of passion," we are led to suppose that the females which 
 are present are thus charmed. 1' The voice of the common 
 
 * Bishop, in Todd's " Cyclop, of Anat. and Phys.," vol. iv, p. 1499. 
 
 f Prof. Newton, " Proc. Zoolog. Soc.," 1871, p. 651. 
 
 \ The spoonbill (Platalea) has its trachea convoluted into a figure 
 of eight, and yet this bird (Jerdon, "Birds of India," vol. iii, p. 763) 
 is mute; but Mr. Blyth informs me that the convolutions are not 
 constantly present, so that perhaps they are now tending toward 
 abortion. 
 
 " Elements of Comp. Anat.," by R. Wagner, Eng, translat., 1845, 
 p. 111. With respect to the swan, as given above, Tarrell's "Hist, 
 of British Birds," 3d edit, 1845, vol. iii, p. 193. 
 
 I C. L. Bonaparte, quoted in the " Naturalist Library; Birds," vol. 
 xiv, p. 126. 
 
 ^[L. Lloyd, " The Game Birds of Sweden." etc., 1867, pp. 22, 81.
 
 426 THE DESCENT OF MAN. 
 
 rook is known to alter during the breeding-season, and is 
 therefore in some way sexual.* But what shall we say 
 about the harsh screams of, for instance, some kinds of 
 macaws; have these birds as bad taste for musical sounds 
 as they apparently have for color, judging by the inhar- 
 monious contrast of their bright yellow and blue plumage? 
 It is indeed possible that without any advantage being thus 
 (gained, the loud voices of many male birds may be the 
 ] result of the inherited effects of the continued use of their 
 vocal organs when excited by the strong passions of love, 
 jealousy and rage; but to this point we shall recur when we 
 treat of quadrupeds. 
 
 We have as yet spoken only of the voice, but the males 
 of various birds practice, during their courtship, what may 
 be called instrumental music. Peacocks and birds of 
 paradise rattle their quills together. Turkey-cocks scrape 
 their wings against the ground, and some kinds of grouse 
 thus produce a buzzing sound. Another North American 
 grouse, the Tetrao unibellus, when with, his tail erect, 
 his ruffs displayed " he shows off his finery to the females 
 who lie hid in the neighborhood,", drums by rapidly striking 
 his wings together above his back, according to Mr. E. 
 Haymond, and not, as Audubon thought, by striking them 
 against his sides. The sound thus produced is compared 
 by some to distant thunder and by others to the quick roll 
 of a drum. The female never drums, " but flies directly 
 to the place where the male is thus engaged. " The male 
 of the Kali j -pheasant in the Himalayas, " often makes a sin- 
 gular drumming noise with his wings, not unlike the sound 
 produced by shaking a stiff piece of cloth." On the west 
 coast of Africa the little black-weavers (Ploceus?) congre- 
 gate in a small party on the bushes round a small open space 
 and sing and glide through the air with quivering wings, 
 ''which make a rapid whirring sound like a child's rattle." 
 One bird after another thus performs for hours together 
 but only during the courting-season. At this season, and 
 at no other time, the males of certain night-jars (Caprimul- 
 gus) make a strange booming noise with their wings. The 
 various species of woodpeckers strike a sonorous branch 
 with their beaks with so rapid a vibratory movement that 
 
 * Jenner, " Pkilosoph. Transactions," 1824, p. 20.
 
 BIRDS. 427 
 
 " the head appears to be in two places at once." The sound 
 thus produced is audible at a considerable distance, but 
 cannot be described; and I feel sure that its source would 
 never be conjectured by any one hearing it for the first 
 time. As this jarring sound is made chiefly during the 
 breeding-season, it has been considered as a love-song; but 
 it is perhaps more strictly a love-call. The female, when 
 driven from her nest, has been observed thus to call her 
 mate, who answered in the same manner and soon appeared. 
 Lastly, the male hoopoe ( Upupa epops] combines vocal 
 and instrumental music; for during the breeding-season 
 this bird, as Mr. Swinhoe observed, first draws in air and 
 then taps the end of its beak perpendicularly down against 
 a stone or the trunk of a tree, " when the breath being 
 forced down the tubular, bill produces the correct sound." 
 If the beak is not thus struck against some object the 
 sound is quite different. Air is at the same time swallowed 
 and the oesophagus thus becomes much swollen; and this 
 probably acts as a resonator, not only with the hoopoe but 
 with pigeons and other birds. * 
 
 In the foregoing cases sounds are made by the aid of 
 structures already present and otherwise necessary; but in 
 the following cases certain feathers have been specially 
 modified for the express purpose of producing sounds. 
 The dramming, bleating, neighing or thundering noise (as 
 expressed by different observers) made by the common 
 snipe (Scolopax gallinago) must have surprised every one 
 who has ever heard it. This bird, during the pairing- 
 season, flies to "perhaps a thousand feet in height," and 
 after zig-zagging about for a time descends to the earth in 
 
 *For the foregoing facts see, on birds of paradise, " Brehm, 
 ' Thierleben," Band iii, s. 325. On grouse, Richardson, "Fauna 
 Bor. Americ.: Birds," pp. 343, 359; Maj. W. Ross King, "The 
 Sportsman in Canada," 1866, p. 156; Mr. Raymond, in Prof. Cox's 
 "Geol. Survey of Indiana," p. 227; Audubon, "American Ornith- 
 olog. Biograph.," vol. i, p. 216. On the Kali j -pheasant, Jerdon, 
 "Birds of India," vol. iii, p. 533. On the weavers, "Livingstone's 
 Expedition to the Zambesi," 1865, p. 425. On woodpeckers, Mac- 
 gillivray, " Hist, of British Birds," vol. iii, 1840, pp. 84, 88, 89, 
 95. On the hoopoe, Mr. Swinhoe, in " Proc. Zoolog. Soc.," June 23, 
 1863, 1871, p. 348. On the night-jar, Audubon, ibid, vol. 
 ii, p. 255, and "American Naturalist," 1873, p. 672. The English 
 night- jar likewise makes in tb*> spring a curious noise during its 
 rapid flight.
 
 428 
 
 THE DESCENT OF MAN. 
 
 a curved line with outspread tail and quivering pinions 
 and surprising velocity. The sound is emitted only during 
 this rapid descent. No one was able to explain the cause 
 until M. Meves observed that on each side of the tail the 
 outer feathers are peculiarly formed (fig. 41), having a 
 
 Fig. 41. Outer tail-feather of Scolopax gallinago (from " Proc. Zool. Soc.," 1858.) 
 
 stiff saber-shaped shaft with the oblique barbs of unusual 
 length, the outer webs being strongly bound together. He 
 found that by blowing on these feathers, or by fastening 
 them to a long, thin stick and waving them rapidly through 
 the air, he could reproduce the drumming noise made by 
 the living bird. Both sexes are furnished with these feath- 
 ers, but they are generally larger in the male than in the 
 female and emit a deeper note. In some species, as in 
 8. frenata (fig. 42), four feathers, and in S. javensis (fig. 
 43), no less than eight on each side of the tail are greatly 
 
 Pig. 42. Outer tail-feather of Scolopax frenata. 
 
 Pig. 43. Outer tail-feather of Scolopax Javensis. 
 
 modified. Different tones are emitted by the feathers of 
 the different species when waved through the air; and the 
 Scolopax Wilsonii of the United States makes a switching 
 noise while descending rapidly to the earth.* 
 
 In the male of the (Jliamcepetes unicolor (a large galli- 
 naceous bird of America), the first primary wing-feather is 
 arched toward the tip and is much more attenuated than in 
 
 *See M. Meves' interesting paper in "Proc. Zool. Soc.," 1858, p. 
 199. For the habits of the snipe, Macgillivray, "Hist. British 
 Birds," vol. iv, p. 371. For the American snipe, Capt. Blakiston, 
 " Ibis," vol. v, 1863, p. 131.
 
 BIRDS. 429 
 
 the female. In an allied bird, the Penelope mgra, Mr. 
 Salvin observed a male, which, while it flew downward 
 " with outstretched wings, gave forth a kind of crashing, 
 rushing noise," like the falling of a tree.* The male 
 alone of one of the Indian bustards (Sypheotides auritus) 
 has its primary wing-feathers greatly acuminated; and the 
 male of an allied species is known to make a humming 
 noise while courting the female, f In a widely different 
 group of birds, namely, humming-birds, the males alone of 
 certain kinds have either the shafts 
 of their primary wing feathers 
 broadly dilated, or the webs ab- 
 ruptly excised toward the extrem- 
 ity. The male, for instance, of 
 SelaspJiorus platycercus, when 
 adult, has the first primary wing- 
 
 leather (hg. 44) tllUS excised. phvrus platycercus (from 
 
 While flying from flower to flower SS*S?vKffi, Yo P 
 
 he makes " a shrill, almost whist- figure, corresponding feather 
 
 ling noise ;"J but it did not appear ' 
 
 to Mr. Salvin that the noise was intentionally made. 
 
 Lastly, in several species of a sub-genus of Pipra or 
 Manakin, the males, as described by Mr. Sclater, have their 
 secondary wing-feathers modified in a still more remarkable 
 manner. In the brilliantly-colored P. deliciosa the first 
 three secondaries are thick-stemmed and curved toward the 
 body; in the fourth and fifth (fig. 45, a) the change is 
 greater; and in the sixth and seventh (b, c) the shaft "is 
 thickened to an extraordinary degree, forming a solid horny 
 lump." The barbs also are greatly changed in shape, in 
 comparison with the corresponding feathers (d, e, /) in the 
 female. Even the bones of the wing, which support these 
 singular feathers in the male, are said by Mr. Fraser to be 
 much thickened. These little birds make an extraordinary 
 noise, the first " sharp note being not unlike the crack of a 
 whip." 
 
 *Mr. Salvin, in "Proc. Zool. Soc.," 1867, p. 160. I am much 
 indebted to this distinguished ornithologist for sketches of the 
 feathers of the Chamaepetes and for other information. 
 
 f Jerdon, "Birds of India," vol. iii, pp. 618, 621. 
 
 JGould, "Introduction to the Trochilidae," 1861, p. 49. Salvin, 
 "Proc. Zoolog. Soc ," 1867, p. 160. 
 
 SclatQr, in "Proc. Zool. Soc.," 1860, p. 90, and in "Ibis," voj, 
 iv, 1862, p. 175. Also Saivin, in ' Ibis," 1860, p. 37.
 
 430 
 
 THE DESCENT OF MAN. 
 
 The diversity of the sounds, both vocal and instrumental, 
 made by the males of many birds during the breeding- 
 
 Fig. 45. Secondary wing-feathers of Pipra deliciosa (from Mr. Sclater, in "Proo. 
 Zool. Soc.," 1800. The three upper feathers, a, 6, c, from the male; the three 
 lower corresponding feathers, d, ,/, from the female. 
 
 a and d, fifth secondary wing-feather of male and female, upper surface. 
 
 b and <?, sixth secondary, upper surface. 
 
 c and/, seventh secondary, upper surface. 
 
 season, and the diversity of the means for producing such 
 sounds, are highly remarkable. We thus gain a high idea 
 of their importance for sexual purposes, and are reminded 
 of the conclusion arrived at as to insects. It is not difficult 
 to imagine the steps by which the notes of a bird, primarily 
 used as a mere call or for some other purpose, might have
 
 BIRDS. 431 
 
 been improved into a melodious love-song. In the case of 
 the modified feathers, by which the drumming, whistling, 
 or roaring noises are produced, we know that some 
 birds during their courtship nutter, shake, or rattle 
 their unmodified feathers together; and if the females were 
 led to select the best performers, the males which possessed 
 the strongest or thickest, or most attenuated feathers, 
 situated on any part of the body, would be the most suc- 
 cessful; and thus by slow degrees the feathers might be 
 modified to almost any extent. The females, of course, 
 would not notice each slight successive alteration in shape, t 
 but only the sounds thus produced. It is a curious fact 
 that in the same class of animals, sounds so different as the 
 drumming of the snipe's tail, the tapping of the wood- 
 pecker's beak, the harsh trumpet-like cry of certain water- 
 fowl, the cooing of the turtle-dove, and the song of the 
 nightingale, should all be pleasing to the females of the 
 several species. But we must not judge of the tastes of 
 distinct species by a uniform standard; nor must we judge 
 by the standard of man's taste. Even with man, we should 
 remember what discordant noises, the beating of tomtoms 
 and the shrill notes of reeds, please the ears of savages. 
 Sir S. Baker remarks,* that " as the stomach of the Arab 
 prefers the raw meat and reeking liver taken hot from the 
 animal, so does his ear prefer his equally coarse and dis- 
 cordant music to all other. " 
 
 Love Antics and Dances. The curious love gestures of 
 some birds have already been incidentally noticed; so 
 that little need here be added. In Northern Amer- 
 ica large numbers of a grouse, the Tetrao phasianellus, 
 meet every morning during the breeding-season on 
 a selected level spot, and here they run round and 
 round in a circle of about fifteen or twenty feet in diam- 
 eter, so that the ground is worn quite bare, like a fairy- 
 ring. In these partridge-dances, as they are called by the 
 hunters, the birds assume the strangest attitudes, and run 
 round, some to the left and some to the right. Audu- 
 bon describes the males of a heron (Ardca hero- 
 dias) as walking about on their long legs with 
 great dignity before the females, bidding defiance to 
 
 *" The Nile Tributaries of Abyssinia," 1867, p. 203-
 
 432 THE DESCENT OF MAN. 
 
 their rivals. With one of the disgusting carrion- 
 vultures (Cathartes jota) the same naturalist states that 
 " the gesticulations and parade of the males at the begin- 
 ning of the love season are extremely ludicrous." Certain 
 birds perform their love antics on the wing, as we have 
 seen with the black African weaver, instead of on tha 
 ground. During the spring our little white throat (Sylvia 
 cinerea) often rises a few feet or yards in the air above 
 some bush and " flutters with a fitful and fantastic motion, 
 singing all the while, and then drops to its perch." The 
 great English bustard throws, himself into indescribably 
 odd attitudes while courting the female, as has been figured 
 by Wolf. An allied Indian bustard (Otis lenyalensis) at 
 such times "rises perpendicularly into the air with a 
 hurried flapping of his wings, raising his crest and puffing 
 out the feathers of his neck and breast and then drops to 
 the ground;" he repeats this maneuver several times, at 
 the same time humming in a peculiar tone. Such females 
 as happen to be near " obey this saltatory summons," and 
 when they approach he trails his wings and spreads his tail 
 like a turkey-cock.* 
 
 But the most curious case is afforded by three allied 
 genera of Australian birds, the famous bower-birds no 
 doubt the co-descendants of some ancient species which 
 first acquired the strange instinct of constructing bower* 
 for performing their love antics. The bowers (fig. 46) 
 which, as we shall hereafter see, are decorated with feath- 
 ers, shells, bones and leaves, are built on the ground for 
 the sole purpose of courtship, for their nests are formed in 
 trees. Both sexes assist in the erection of the bowers, but 
 the male is the principal workman. So strong is this 
 instinct that it is practiced under confinement, and Mr. 
 Strange has describedf the habits of some satin bower-bird^ 
 which he kept in an aviary in New South Wales. "At 
 
 *For Tetrao phasiancttus, see Richardson, " Fauna, Bor. Amer- 
 ica," p. 361, and for further particulars, Capt. Blakiston, "Ibis," 
 1863, p. 125. For the Cathartes and Ardea, Audubon, " Ornith. 
 Biography," vol. ii, p. 51, and vol. iii, p. 89. On the white-throat, 
 Macgillivray, "Hist. British Birds," vol. ii, p. 354. On the Indian 
 bustard, Jerdon, " Birds of India," vol. iii, p. 618. 
 
 f Gould, " Hand-book to the Birds of Australia," vol. i, pp. 444. 
 449, 455. The bower of the satin bower-bird may be seen in the 
 Zoological Society's Gardens, Regent Park.
 
 BIEDS. 433 
 
 times the male will chase the female all over the aviary, 
 
 then go to the bower, pick up a gay feather or a large leaf, 
 utter a curious kind of note, set all his feathers erect, run 
 round the bower and become so excised that his eyes appear
 
 434 THE DESCENT OF MAN. 
 
 ready to start from his head ; he continues opening first one 
 wing, then the other, uttering a low, whistling note, and, 
 like the domestic cock, seems to be picking up something 
 from the ground, until at last the female goes gently 
 toward him." Capt. Stokes has described the habits and 
 "play-houses" of another species, the great bower-bird, 
 which was seen "amusing itself by flying backward and 
 forward, taking a shell alternately from each side and 
 carrying it through the archway in its mouth." These 
 curious structures, formed solely as halls of assemblage, 
 where both sexes amuse themselves and pay their court, 
 must cost the birds much labor. The bower, for instance, 
 of the fawn-breasted species is nearly four feet in length, 
 eighteen inches in height, and is raised on a thick platform 
 of sticks. 
 
 Decoration. I will first discuss the cases in which the 
 males are ornamented either exclusively or in a much 
 higher degree than the females, and in a succeeding 
 chapter those in which both sexes are equally ornamented, 
 and finally the rare cases in which the female is somewhat 
 more brightly colored than the male. As with the artificial 
 ornaments used by savage and civilized men so with the nat- 
 ural ornaments of birds, the head is the chief seat of 
 decoration.* The ornaments,' as mentioned at the com- 
 mencement of this chapter, are wonderfully diversified. The 
 plumes on the front or back of the head consist of variously- 
 shaped feathers, sometimes capable of erection or expan- 
 sion, by which their beautiful colors are fully displayed. 
 Elegant ear -tufts (see fig. 39, ante) are occasionally 
 present. The head is sometimes covered with velvety 
 down, as with the pheasant ; or is naked and vividly 
 colored. The throat, also, is sometimes wnameuted with 
 a beard, wattles or caruncles. Such appendages are gen- 
 erally brightly colored and no doubt serve as ornaments, 
 though not always ornamental in our eyes; for while the 
 male is in the act of courting the female they often swell 
 and assume vivid tints, as in the male turkey. At such 
 times the fleshy appendages about the head of the male 
 Tragopan pheasant ( Ceriornis Temminckii) swell into a large 
 
 *See remarks to this effect, on the "Feeling of Beauty Among 
 Animals," by Mr. J. Shaw, in the "Athenaeum," Nov. 24, 1866, p. 
 681.
 
 BIRDS. 435 
 
 lappet on the throat and into two horns, one on each side 
 of the splendid top-knot; and these are then colored of the 
 most intense blue which I have ever beheld. * The African 
 hornbill (Bucorax abyssinicus] inflates the scarlet bladder- 
 like wattle on its neck, and with its wings drooping and 
 tail expanded "makes quite a grand appearance."! Even 
 the iris of the eye is sometimes more brightly colored in 
 the male than in the female; and this is frequently the 
 case with the beak, for instance, in our common blackbird. 
 In Buceros corrugatus the whole beak and immense casque 
 are colored more conspicuously in the male than in the 
 female; and " the oblique grooves upon the sides of the 
 lower mandible are peculiar to the male sex."J 
 
 The head, again, often supports fleshy appendages, fila- 
 ments, and solid protuberances. These, if not common to 
 both sexes, are always confined to the males. The solid 
 protuberances have been described in detail by Dr. W. 
 Marshall, who shows that they are formed either of can- 
 cellated bone coated with skin, or of dermal and other 
 tissues. With mammals true horns are always supported 
 on the frontal bones, but with birds various bones have 
 been modified for this purpose; and in species of the same 
 group the protuberances may have cores of bone, or be 
 quite destitute of them, with intermediate gradations con- 
 necting these two extremes. Hence, as Dr. Marshall 
 justly remarks, variations of the most different kinds have 
 served for the development through sexual selection of 
 these ornamental appendages. Elongated feathers or 
 plumes spring from almost every part of the body. The 
 feathers on the throat and breast are sometimes developed 
 into beautiful ruffs and collars. The tail-feathers are fre- 
 quently increased in length; as we see in the tail-coverts of 
 the peacock, and in the tail itself of the Argus pheasant. 
 With the peacock even the bones of the tail have been 
 modified to support the heavy tail-coverts. || The body of 
 
 *See Dr. Murie's account with colored figures in " Proc. Zoolog. 
 Soc.," 1872, p. 730. 
 
 fMr. Monteiro, "Ibis," vol. iv., 1862, p. 339. 
 
 j " Land and Water," 1868, p. 217. 
 
 "Ueber die SchadelhScker," etc., " Mederlandischen Archiv. 
 fur Zoologie," B. I., Heft. 2, 1872. 
 
 HDr. W.-Marshall, " Ueber den Vogelschwanz," ibid, B. I., Heft 
 2, 1872.
 
 436 THE DESCENT OF MAN. 
 
 the Argus is not larger than that of a fowl; yet the length 
 from the end of the beak to the extremity of the tail is no 
 less than five feet three inches,* and that of the beauti- 
 fully ocellated secondary wing- feathers nearly three feet. 
 In a small African night-jar ( Cosmetornis vexillarius) one 
 of the primary wing-feathers, during the breeding-season, 
 attains a length of twenty-six inches, while the bird itself 
 is only ten inches in length. In another closely allied 
 genus of night-jars, the shafts of the elongated wing- 
 feathers are naked, except at the extremity, where there is 
 a disk, f Again, in another genus of night-jars, the tail- 
 feathers are even still more prodigiously developed. In 
 general the feathers of the tail are more often elongated 
 than those of the wings, as any great elongation of the 
 latter impedes flight. We thus see that in closely-allied 
 birds ornaments of the same kind have been gained 
 by the males through the development of widely different 
 feathers. 
 
 It is a curious fact that the feathers of species belonging 
 to very distinct groups have been modified in almost 
 exactly the same peculiar manner. Thus the wing-feathers 
 in one of the above-mentioned night-jars are bare along the 
 shaft, and terminate in a disk; or are, as they are sometimes 
 called, spoon or racket shaped. Feathers of this kind occur 
 in the tail of a motmot (Eitmomota superciliaris), of a king- 
 fisher, finch, humming-bird, parrot, several Indian drongos 
 (Dicrurus and Edolius, in one of which the disk stands 
 vertically), and in the tail of certain birds of paradise. 
 In these latter birds, similar feathers, beautifully ocellated, 
 ornament the head, as is likewise the case with some galli- 
 naceous birds. In an Indian bustard (Syplieotides auritus) 
 the feathers forming the ear-tufts, which are about four 
 inches in length, also terminate in disks. J It is a most 
 singular fact that the motmots, as Mr. Salvin has clearly 
 shown, give to their tail-feathers the racket-shape by 
 biting of! the barbs, and, further, that this continued 
 mutilation has produced a certain amount of inherited 
 effect. 
 
 * Jardine's "Naturalist Library; Birds," vol. xiv, p. 166. 
 
 f Sclater, in the " Ibis," vol. vi, 1864, p. 114. Livingstone, " Expe- 
 dition to the Zambesi," 1865, p. 66. 
 
 JJerdon, "Birds of India," vol. iii, p. 620. 
 
 "Proc. Zoolog. Soc.," 1873, p. 429.
 
 BIRDS. 437 
 
 Again,, the barbs of the feathers in various widely-distinct 
 birds are filamentous or plumose, as with some herons, 
 
 Fig. 47. Paradisea Papuana (T. W. Wood). 
 
 ibises, birds of paradise, and Gallinaceae. In other cases the 
 barbs disappear, leaving the shafts bare from end to end;
 
 438 THE DESCENT OF MAN. 
 
 and these in the tail of the Paradisca apoda attain a 
 length of thirty-four inches;* in P. Papuana (fig. 47) 
 they are much shorter and thin. Smaller feathers when 
 thus denuded appear like bristles, as on the breast of the 
 turkey-cock. As any fleeting fashion in dress comes to be 
 admired by man, so with birds a change of almost any 
 kind in the structure or coloring of the feathers in the 
 male appears to have been admired by the female. The 
 fact of the feathers in widely distinct groups having 
 been modified in an anologous manner no doubt 
 depends primarily on all the feathers having nearly 
 the same structure and manner of development, and 
 consequently tending to vary in the same manner. We 
 often see a tendency to analogous variability in the 
 plumage of our domestic breeds belonging to dis- 
 tinct species. Thus top-knots have appeared in several 
 species. In an extinct variety of the turkey the top-knot 
 consisted of bare quills surmounted with plumes of down, 
 so that they somewhat resembled the racket-shaped feathers 
 above described. In certain breeds of the pigeon and fowl the 
 feathers are plumose, with some tendency in the shafts to 
 be naked. In the Sebastopol goose the scapular feathers 
 are greatly elongated, curled, or even spirally twisted, with 
 the margins plumose, f 
 
 In regard to color, hardly anything need here be said, 
 for every one knows how splendid are the tints of many 
 birds and how harmoniously they are combined. The 
 colors are often metallic and iridescent. Circular spots 
 are sometimes surrounded by one or more differently 
 shaded zones and are thus converted into ocelli. Nor need 
 much be said on the wonderful difference between the 
 sexes of many birds. The common peacock offers a strik- 
 ing instance. Female birds of paradise are obscurely col- 
 ored and destitute of all ornaments, while the males are 
 probably the most highly decorated of all birds, and in so 
 many different ways that they must be seen to be appre- 
 ciated. The elongated and golden-orange plumes which 
 spring from beneath the wings of the Paradisea apoda 
 when vertically erected and made to vibrate are described 
 
 * Wallace, in "Annals and Mag. of Nat. Hist.," vol. xx, 1857, p. 
 416, and in his " Malay Archipelago," vol. ii, 1869, p. 390. 
 
 fSee my work on " The Variation of Animals and Plants under 
 Domestication," vol. i, pp. 289, 293.
 
 BIRDS. 
 
 439 
 
 as forming a sort of halo, in the center of which the head 
 " looks like a little emerald sun with, its rays formed by 
 
 Fig, 48. Lophornis ornatus, male and female (from Brehm). 
 
 the two plumes."* In another most beautiful species the 
 head is bald " and of a rich cobalt blue, crossed by several 
 lines of black velvety feathers."! 
 
 *Quoted from M. de Lafresnaye in " Annals and Mag. of Nat. 
 Hist.," vol. xiii, 1854, p. 157: see also Mr. Wallace's much fuller 
 account in vol. xx, 1857, p. 412, and in his "Malay Archipelago." 
 ,f Wallace, " The Malay Archipelago," vol. ii, 1869, p. 405.
 
 440 
 
 THE DESCENT OF MAN. 
 
 Male humming-birds (figs. 48 and 49) almost vie with, 
 birds of paradise in their beauty, as every one will admit 
 
 Fig. 49. Spathura underwoodi, male and female (from Brehrn). 
 
 who has seen Mr. Gould's splendid volumes or his rich col- 
 lection. It is very remarkable in how many different ways
 
 BIRDS. 441 
 
 these birds are ornamented. Almost every part of their 
 plumage has been taken advantage of and modified; and 
 the modifications have been carried, as Mr. Gould showed 
 me, to a wonderful extreme in some species belonging to 
 nearly every sub-group. Such cases are curiously like 
 those which we see in our fancy breeds, reared by man for 
 the sake of ornament; certain individuals originally varied 
 in one character, and other individuals of the same species 
 in other characters; and these have been seized on by man 
 and much augmented, as shown by the tail of the fantail- 
 pigeon, the hood of the jacobin, the beak and wattle of 
 the carrier, and so forth. The sole difference between these 
 cases is that in the one the result is due to man's selection, 
 while in the other, as with humming-birds, birds of para- 
 dise, etc., it is due to the selection by the females of the 
 more beautiful males. 
 
 I will mention only one other bird, remarkable from the 
 extreme contrast in color between the sexes, namely, the 
 famous bell-bird (ChasmorhyncJms niveus) of South 
 America, the note of which can be distinguished at the 
 distance of nearly three miles, and astonishes every one 
 when first hearing it. The male is pure white, while the 
 female is dusky-green; and white is a very rare color in ter- 
 restrial species of moderate size and inoffensive habits. 
 The male, also, as described by Waterton, has a spiral tube 
 nearly three inches in length, which rises from the base of 
 the beak. It is jet-black, dotted over with minute downy 
 feathers. This tube can be inflated with air, through a 
 communication with the palate ; and when not inflated 
 hangs dcrwn on one side. The genus consists of four species, 
 the males of which are very distinct, while the females, as 
 described by Mr. Sclater in a very interesting paper, closely 
 resemble each other, thus offering an excellent instance of 
 the common rule that within the same group the males 
 differ much more from each other than do the females. In 
 a second species (C. nudicollis) the male is likewise snow- 
 white, with the exception of a large space of naked skin 
 on the throat and round the eyes, which during the breed- 
 ing-season is of a fine green color. In the third species 
 (C. tricarunculatus) the head and neck alone of the male 
 are white, the rest of the body being chestnut-brown, and 
 the male of this species is provided with three filamentous 
 projections' half as long a,s the .body, one rising from the
 
 442 THE DESCENT OF MAN. 
 
 base of the beak and the two others from the corners of the 
 mouth.* 
 
 The colored plumage and certain other ornaments of the 
 adult males are either retained for life or are periodically 
 renewed during the summer and breeding-season. At this 
 same season the beak and naked skin about the head fre- 
 quently change color, as with some herons, ibises, gulls, 
 one of the bell-birds just noticed, etc. In the white ibis, 
 the cheeks, the inflatable skin of the throat, and the basal 
 portion of the beak then become crimson, f In one of the 
 rails, Gallicrex cristatus, a large red caruncle is developed 
 during this period on the head of the male. So it is with 
 a thin horny crest on the beak of one of the pelicans, P. 
 erythrorhynclms; for, after the breeding-season, these horny 
 crests are shed, like horns from the heads of stags, and the 
 shore of an island in' a lake in Nevada was found covered 
 with these curious exu,viae. J 
 
 Changes of color inMite plumage according to the season 
 depend, firstly on a double annual moult, secondly on an 
 actual change of color in the feathers themselves, and 
 thirdly on their dull-colored margins being periodically 
 shed, or on these three processes more or less combined. 
 The shedding of the deciduary margins may be compared 
 with the shedding of their down by very young birds; for 
 the down in most cases arises from the summits of the first 
 true feathers. 
 
 With respect to the birds which annually undergo a 
 double moult, there are, firstly, some kinds, for instance 
 snipes, swallow-plovers (Glareolae), and curlews, in which 
 the two sexes resemble each other and do not change color 
 at any season. I do not know whether the winter plumage 
 is thicker and warmer than the summer plumage, but 
 warmth seems the most probable end attained of a double 
 moult, where there is no change of color. Secondly, there 
 are birds, for instance, certain species of Totanus and other 
 
 *Mr. Scfctui, " Intellectual Observer," Jan., 1867. " Waterton's 
 Wanirto^n " ]\ 118. See also Mr. Salvin's interesting paper, with 
 plate, in tb " Ibis," 1865, p. 90. 
 
 f'LMHJ a.l Water," 1867, p. 394. 
 
 tMr. >. O. Klliot, in " Proc. Zool. Soc.," 1869, p. 589. 
 
 8 NHwr,K' ' Pterylography," edited by P. L. Sclater. Ray Soc., 
 1067, ( . &.
 
 BIRDS. 443 
 
 t??allatores, the sexes of which resemble each other, but in 
 which the summer and winter plumage differ slightly in 
 color. The difference,, however, in these cases is so small 
 that it can hardly be an advantage to them; and it may, 
 perhaps, be attributed to the direct action of the different 
 conditions to which the birds are exposed during the two 
 seasons. Thirdly, there are many other birds the sexes of 
 which are alike, but which are widely different in their 
 summer and winter plumage. Fourthly, there are birds 
 the sexes of which differ from each other in color; but the 
 females, though moulting twice, retain the same colors 
 throughout the year, while the males undergo a change of 
 color, sometimes a great one, as with certain bustards. 
 Fifthly and lastly, there are birds the sexes of which differ 
 from each other in both their summer and winter plumage; 
 but the male undergoes a greater amount of change at each 
 recurrent season than the female of which the ruff ( Ma- 
 chetes pugnax) offers a good instance. 
 
 With respect to the cause or purpose of the differences 
 in color between the summer and winter plumage, this may 
 in some instances, as with the ptarmigan,* serve during 
 both seasons as a protection. When the difference between 
 the two plumages is slight it may perhaps be attributed, as 
 already remarked, to the direct action of the conditions of 
 life. But with many birds there can hardly be a doubt 
 that the summer plumage is ornamental, even when both 
 sexes are alike. We may conclude that this is the case with 
 many herons, egrets, etc., for they acquire their beautiful 
 plumes only during the breeding-season. Moreover, such 
 plumes, top-knots, etc., though possessed by both sexe^ 
 are occasionally a little more developed in the male than in 
 the female; and they resemble the plumes and ornaments 
 possessed by the males alone of other birds. It is also known 
 that confinement, by affecting the reproductive system of 
 male birds, frequently checks the development of their 
 secondary sexual characters, but has no immediate influence 
 on any other characters; and I am informed by Mr. Bart- 
 
 * The brown mottled summer plumage of the ptarmigan is of aa 
 much importance to it, as a protection, as the white winter plumage; 
 for in Scandinavia during the spring, when the snow has disap- 
 
 nred, this bird is known to suffer greatly from birds of prey, before 
 AS acquired its summer dress; see Wilhelm. von Wright, b 
 Llcyd, Game Birds of Sweden," 1807, p. 125,
 
 444 THE DESCENT OF MAN. 
 
 lett that eight or nine specimens of the Knot (Tnnga 
 canutus) retained their unadorned winter plumage in the 
 Zoological Gardens throughout the year, from which fact 
 we may infer that the summer plumage, though common 
 to both sexes, partakes of the nature of the exclusively 
 masculine plumage of many other birds.* 
 
 From the foregoing facts, more especially from neither 
 sex of certain birds changing color during either annual 
 moult, or changing so slightly that the change can hardly 
 be of any service to them, and from the females of other 
 species moulting twice yet retaining the same color through- 
 out the year, we may conclude that the habit of annually 
 moulting twice has not been acquired in order that the- 
 male should assume an ornamental character during the 
 breeding-season; but that the double moult, having been 
 originally acquired for some distinct purpose, has subse- 
 quently been taken advantage of in certain cases for gaining 
 a nuptial plumage. 
 
 It appears at first sight a surprising circumstance that 
 some closely-allied species should regularly undergo a 
 double annual moult, and others only a single one. The 
 ptarmigan, for instance, moults twice or even thrice in the 
 jrear, and the black-cock only once; some of the splen- 
 didly colored honey-suckers (Nectariniae) of India and 
 some sub-genera of obscurely colored pipits (Anthus) have 
 a double, while others have only a single annual moult, f 
 But the gradations in the manner of moulting, which 
 are known to occur with various birds, show us 
 how species or whole groups might have originally 
 acquired their double annual moult, or having once 
 gained the habit, have again lost it. With certain bus- 
 tards and plovers the vernal moult is far from complete, 
 some feathers being renewed, and some changed in 
 color. There is also reason to believe that with certain 
 
 * In regard to the previous statements on moulting, see, on snipes, 
 etc., Macgillivray, " Hist. Brit. Birds," vol. iv, p. 371; on Glareolae, 
 
 curlews and bustards, Jerdon, " Birds of India," vol. iii, pp. 615, 
 630, 683; on Totanus, ibid, p. 700; on the plumes of herons, ibid, p. 
 738, and Macgillivray, vol. iv, pp. 435, 444, and Mr. Stafford Allen, 
 in the "Ibis," vol. v, 1863, p. 33. 
 
 | On the moulting of the ptarmigan, see Gould's " Birds of Great 
 Britain." On the I^oney-suckers, Jerdon, "Bjrds of India," vol. i, 
 pp. 359, 865, 869. On the moulting qf ^thue, roe Blorth, in " Ibis,'' 
 1867. p. 32.
 
 BIRDS. 445 
 
 bustards and rail-like birds, which properly undergo a 
 double moult, some of the older males retain their nuptial 
 plumage throughout the year. A few highly modified 
 feathers may merely be added during the spring to the 
 plumage, as occurs with the disk-formed tail-feathers of 
 certain drongos (Bhringa) in India, and with the elon- 
 gated feathers on the back, neck, and crest of certain 
 herons. By such steps as these, the vernal moult might 
 be rendered more and more complete, until a perfect 
 double moult was acquired. Some of the birds of paradise 
 retain their nuptial feathers throughout the year, and thus 
 have only a single moult ; others cast them directly after 
 the breeding-season, and thus have a double moult; and 
 others again cast them at this season during the first year, 
 but not afterward; so that these latter species are interme- 
 diate in their manner of moulting. There is also a great 
 difference with many birds in the length of time during 
 which the two annual plumages are retained ; so that the 
 one might come to be retained for the whole year, and 
 the other completely lost. Thus in the spring Machetes 
 pugnax retains his ruff for barely two months. In 
 Natal the male widow-bird (Chera progne) acquires his 
 fine plumage and long tail-feathers in December or Janu- 
 ary, and loses them in March ; so that they are retained 
 only for about three months. Most species which undergo 
 a double moult keep their ornamental feathers for about 
 six months. The male, however, of the wild Gallus ban- 
 kiva retains his neck-hackles for nine or ten months; and 
 when these are cast off the underlying black feathers on 
 the neck are fully exposed to view. But with the domesti- 
 cated descendant of this species the neck-hackles of the 
 male are immediately replaced by new ones ; so that we 
 here see, as to part of the plumage, a double moult changed 
 under domestication into a single moult.* 
 
 * For the foregoing statements in regard to partial moults, and on 
 old males retaining their nuptial plumage, see Jerdon, on bustards 
 and plovers, in " Birds of India," vol. iii, pp. 617, 637, 709, 711. 
 Also Blyth in " Land and Water," 1867, p. 84. On the moulting of 
 Paradisea, see an interesting article by Dr. W. Marshall, " Archives 
 Neerlandaises," torn, vi, 1871. On the Vidua, " Ibis," vol. iii, 1861, 
 p. 133. On the Drongo-shrikes, Jerdon, ibid, vol. i, p. 435. On the 
 vernal moult of the Herodias bubulcus, Mr. S. S. Allen, in " Ibis," 
 1863, p. 33. On Gallus liankiva, Blyth, in " Annals and Mag. of 
 Nat. Hist.," vol. i, 1848, p. 455; see also on this subject, my " Vari- 
 ation of Animals under Domestication," vol. i, p. 236.
 
 446 THE DESCENT OF MAN. 
 
 The common drake (Anas boschas) after the breeding- 
 season, is well known to lose his male plumage for a 
 period of three months, during which time he assumes 
 that of the female. The male pin-tail duck (Anas acutd) 
 loses his plumage for the shorter period of six weeks or 
 two months ; and Montagu remarks that " this double 
 moult within so short a time is a most extraordinary cir- 
 cumstance that seems to bid defiance to all human reason- 
 ing. " But the believer in the gradual modification of 
 species will be far from feeling surprise at finding grada- 
 tions of all kinds. If the male pin-tail were to acquire his 
 new plumage within a still shorter period the new male 
 feathers would almost necessarily be mingled with the old, 
 and both with some proper to the female; and this appar- 
 ently is the case with the male of a not distantly allied 
 bird, namely, the Merganser serrator, for the males are 
 said to " undergo a change of plumage which assimilates 
 them in some measure to the female." By a little further 
 acceleration in the process the double moult would be com- 
 pletely lost.* 
 
 Some male birds, as before stated, become more brightly 
 colored in the spring, not by a vernal moult, but either by 
 an actual change of color in the feathers or by their 
 obscurely colored deciduary margins being shed. Changes 
 of color thus caused may last for a longer or shorter time. 
 In the Pelecanus onocrotalus a beautiful rosy tint with 
 lemon-colored marks on the breast overspreads the whole 
 plumage in the spring; but these tints, as Mr. Sclater 
 states, " do not last Igng, disappearing generally in about 
 six weeks or two months after they have been attained." 
 Certain finches shed the margins of their feathers in the 
 spring and then become brighter colored, while other 
 finches undergo no such change. Thus the Fringilla 
 tristis of the U nited States (as well as many other Ameri- 
 can species) exhibits its bright colors only when the winter 
 is past, while our goldfinch, which exactly represents this 
 bird in habits, and our siskin which represents it still more 
 closely in structure, undergo no such annual change. But 
 a difference of this kind in the plumage of allied species 
 
 *See Macgillivray, "Hist. British Birds," (vol. v, pp. 34, 70, 223) 
 on the moulting of the Anatklae, with quotations from Waterton and 
 Montagu. Also Yarrell, " Hist, of British Birds," vol. iii, p. 243.
 
 BIRDS. 447 
 
 is not surprising, for with the common linnet, which 
 belongs to the same family, the crimson forehead and 
 breast are displayed only during the summer in England, 
 while in Madeira these colors are retained throughout the 
 year. * 
 
 Display by Male Birds of Tlieir Plumage. Ornaments 
 of all kinds, whether permanently or temporarily gained, 
 are sedulously displayed by the males, and apparently serve 
 to excite, attract or fascinate the females. But the males 
 will sometimes display their ornaments when, not in the 
 presence of the females, as occasionally occurs with grouse 
 at their balz-places, and as may be noticed with the 
 peacock; this latter bird, however, evidently wishes for a 
 spectator of some kind, and, as I have often seen, will show 
 off his finery before poultry, or even pigs, f All naturalists 
 who have closely attended to the habits of birds, whether 
 in a state of nature or under confinement, are unani- 
 mously of opinion that the males take delight in displaying 
 their beauty. Audubon frequently speaks of the male as 
 endeavoring in various ways to charm the female. Mr. 
 Gould, after describing some peculiarities in a male 
 humming-bird, says lie lias no doubt that it has the power 
 of displaying them to the greatest advantage before the 
 female. Dr. JerdonJ insists that the beautiful plumage of 
 the male serves " to fascinate and attract the female." 
 Mr. Bartlett, at the Zoological Gardens, expressed himself 
 to me in the strongest terms to the same effect. 
 
 It must be a grand sight in the forests of India ' ' to come 
 suddenly on twenty or thirty pea-fowl, the males displaying 
 their gorgeous trains, and strutting about in all the pomp 
 of pride before the gratified females/' The wild turkey-cock 
 erects his glittering plumage, expands his finely-zoned tail 
 and barred wing-feathers, and altogether, with his crimson 
 
 On the pelican, see Sclater, in "Proc. Zool. Soc.," 1868, p. 265. 
 he American finches, see Audubon, " Ornith. Biography," vol. i, 
 174, 221, and Jerdon, " Birds of India," vol. ii, p. 383. On the 
 
 On the American finches, see Audubon, " Ornith. Biography," vol. i, 
 pp. 174, 221, and Jerdon, " Birds of India," vol. ii, p. 383. On the 
 Fringilla canndbina of Madeira, Mr. E. Vernon Harcourt, " Ibis," 
 
 vol. v, 1863, p. 230. 
 
 fSee also " Ornamental Poultry," by Rev. E. S. Dixon, 1848, p. 8. 
 
 | " Birds of India," introduct., vol. i, p. 24, on the peacock, vol. 
 iii, p. 507. See Gould's " Introduction to the Trochilid*," 1861, pp. 
 15, 111.
 
 448 THE DESCENT OF MAN. 
 
 and blue wattles, makes a superb, though, to our eyes, 
 grotesque appearance. Similar facts have already been 
 given with respect to grouse of various kinds. Turning to 
 another order. The male Rupicola crocea (fig. 50) is one 
 of the most beautiful birds in the world, being of a splendid 
 orange, with some of the feathers curiously truncated and 
 
 Fig. 50. Rupicola crocea, male (T. W. Wood). 
 
 plumose. The female is brownish -green, shaded with red, 
 and has a much smaller crest. Sir R. Schomburgk has 
 described their courtship; he found one of their meeting- 
 places where ten males and two females were present. The 
 space was from four to five feet in diameter, and appeared 
 to have been cleared of every blade of grass and smoothed 
 as if by human hands. A^U^le^" was capering te the
 
 BIRDS. 449 
 
 apparent delight of several others. Now spreading its 
 wings, throwing up its head, or opening its tail like a fan; 
 now strutting about with a hopping gait until tired, when 
 it gabbled some kind of note, and was relieved by another. 
 Thus three of them successively took the field, and then, 
 with self -approbation, withdrew to rest." The Indians, in 
 order to obtain their skins, wait at one of the meeting- 
 places till the birds are eagerly engaged in dancing, and 
 then are able to kill with their poisoned arrows four or five 
 males, one after the other.* AVith birds of paradise a dozen 
 or more full-plumaged males congregate in a tree to hold a 
 dancing-party, as it is called by the natives; and here they 
 fly about, raise their wings, elevate their exquisite plumes, 
 and make them vibrate, and the whole tree seems, as Mr. 
 Wallace remarks, to be filled with waving plumes. When 
 thus engaged they become so absorbed that a skillful archer 
 may shoot nearly the whole party. These birds, when kept 
 in confinement in the Malay Archipelago, are said to take 
 much care in keeping their feathers clean; often spreading 
 them out, examining them, and removing every speck of 
 dirt. One observer, who kept several pairs alive, did not 
 doubt that the display of the male was intended to please 
 the female, f 
 
 The gold and Amherst pheasants during their courtship 
 not only expand and raise their splendid frills but twist 
 them, as I have myself seen, obliquely toward the female 
 on whichever side she may be standing, obviously in order 
 that a large surface may be displayed before her.]; They 
 likewise turn their beautiful tails and tail-coverts a little 
 toward the same side. Mr. Bartlett has observed a male 
 Polyplectron (fig. 51) in the act of courtship, and has 
 shown me a specimen stuffed in the attitude then assumed. 
 The tail and wing feathers of this bird are ornamented 
 with beautiful ocelli, like those on the peacock's train. 
 
 * " Journal of R. Geograph. Soc.," vol. x, 1840, p. 236. 
 
 f" Annals and Mag. of Nat. Hist.," vol. xiii, 1854, p. 157; also 
 Wallace, ibid, vol. xx, 1857, p. 412, and "The Malay Archipelago," 
 vol. ii, 1869, p. 252. Also Dr. Bennett, as quoted by Brehni, " Thier- 
 leben/'^B. iii, s. 326. 
 
 JMr.'T. W. Wood has given ("The Student," April, 1870, p. 
 115) a full account of this manner of display by the gold pheasant 
 and by the Japanese pheasant, Ph. versicolor; and he calls it the 
 lateral or one-sided display.
 
 4:50 THE DESCENT OF MAN. 
 
 Now when the peacock displays himself he expands and 
 
 Fig. 51. Polyplectron chinquis, male (T. W. Wuod). 
 
 erects his tail transversely to his body, for he stands in 
 front of the female, and has to show olf at the same time
 
 BIRDS. 451 
 
 his rich blue throat and breast. But the breast of the Poly- 
 plectron is obscurely colored, and the ocelli are not con- 
 fined to the tail-feathers. Consequently the Polyplectron 
 does not stand in front of the female; but he erects and 
 expands his tail-feathers a little obliquely, lowering the ex- 
 panded wing on the same side and raising that on the 
 opposite side. In this attitude the ocelli over the whole 
 body are exposed at the same time before the eyes of the 
 admiring female in one grand bespangled expanse. To 
 whichever side she may turn the expanded wings and the 
 obliquely-held tail are turned toward her. The male Trag- 
 opan pheasant acts in nearly the same manner, for he raises 
 the feathers of the body, though not the wing itself, on the 
 side which is opposite to the female, and which would 
 otherwise be concealed, so that nearly all the beautifully 
 spotted feathers are exhibited at the same time. 
 
 The Argus pheasant affords a much more remarkable 
 case. The immensely developed secondary wing-feathers 
 are confined to the male; and each is ornamented with a 
 row of from twenty to twenty-three ocelli above an inch in 
 diameter. These feathers are also elegantly marked with 
 oblique stripes and rows of spots of a dark color, like those 
 on the skin of a tiger and leopard combined. These beau- 
 tiful ornaments are hidden until the male shows himself off 
 before the female. He then erects his tail and expands his 
 wing-feathers into a great, almost upright, circular fan or 
 shield, which is carried in front of the body. The neck 
 and head are held on one side, so that they are concealed 
 by the fan; but the bird in order to see the female, before 
 whom he is displaying himself, sometimes pushes his head 
 between two of the long wing-feathers (as Mr. Bartlett has 
 seen), and then presents a grotesque appearance. This 
 must be a frequent habit with the bird in a state of nature, 
 for Mr. Bartlett and his son, on examining some perfect 
 skins sent from the east, found a place between two of the 
 .feathers which was much frayed, as if the head had here 
 frequently been pushed through. Mr. Wood thinks that 
 the male can also peep at the female on one side beyond the 
 margin of the fan. 
 
 The 'ocelli on the wing-feathers are wonderful objects, 
 for they are so shaded that, as the Duke of Argyll remarks,* 
 
 * "The Reign of Law," 1867, p. 203.
 
 452 THE DESCENT OF MAN. 
 
 they stand out like balls lying loosely within sockets. When 
 
 Fig. 52. Side view of male Argus pheasant, while displaying before the 
 female. Observed and sketched from nature by Mr. T. W. Wood. 
 
 I looked at the specimen in the British Museum, which is 
 mounted with the wings expanded and trailing downward,
 
 BIRDS. 453 
 
 I was, however, greatly disappointed, for the ocelli appeared 
 flat, or even concave. But Mr. Gould soon made the case 
 clear to me, for he held the feathers erect, in the position 
 in which they would naturally be displayed, and now, from 
 the light shining on them from above, each ocellus at once 
 resembled the ornament called a ball and socket. These 
 feathers have been shown to several artists, and all have 
 expressed their admiration at the perfect shading. It may 
 well be asked, could such artistically shaded ornaments 
 have been formed by means of sexual selection ? But it 
 will be convenient to defer giving an answer to this ques- 
 tion until we treat in the next chapter of the principle of 
 gradation. 
 
 The foregoing remarks relate to the secondary wing- 
 feathers, but the primary wing-feathers, which in most 
 gallinaceous birds are uniformly colored, are in the Argus 
 pheasant equally wonderful. They are of a soft brown tint 
 with numerous dark spots, each of which consists of two or 
 three black dots with a surrounding dark zone. But the 
 chief ornament is a space parallel to the dark-blue shaft, 
 which in outline forms a perfect second feather lying within 
 the true feather. This inner part is colored of a lighter 
 chestnut, and is thickly dotted with minute white points. 
 I have shown this feather to several persons, and many 
 have admired it even more than the ball and socket feath- 
 ers, and have declared that it was more like a work of art 
 than of nature. Now these feathers are quite hidden on 
 all ordinary occasions, but are fully displayed, together 
 with the long secondary feathers, when they are all ex- 
 panded together so as to form the great fan or shield. 
 
 The case of the male Argus pheasant is eminently inter- 
 esting, because it affords good evidence that the most re- 
 fined beauty may serve as a sexual charm, and for no other 
 purpose. We must conclude that this is the case, as the 
 secondary and primary wing-feathers are not at all dis- 
 played, and the ball and socket ornaments are not exhibited 
 in mil perfection until the male assumes the attitude of 
 courtship. The Argus pheasant does not possess brilliant 
 colors, so that his success in love appears to depend on the 
 great size of his plumes and on the elaboration of the most 
 elegant patterns. Many will declare that it is utterly in- 
 credible that a female bird should be able to appreciate fine 
 ehading and exquisite patterns. It is undoubtedly a mar-
 
 454 THE DESCENT OF MAN. 
 
 velous fact that she should possess this almost human degree 
 of taste. He who thinks that he can safely gauge the dis- 
 crimination and taste of the lower animals" may deny that 
 the female Argus pheasant can appreciate such refined 
 beauty; but he will then be compelled to admit that the 
 extraordinary attitudes assumed by the male during the act 
 of courtship, by which the wonderful beauty of his plum- 
 age is fully displayed, are purposeless; and this is a conclu- 
 sion which I for one will never admit. 
 
 Although so many pheasants and allied gallinaceous 
 birds carefully display their plumage before the females, it 
 is remarkable, as Mr. Bartlett informs me, that this is not 
 the case with the dull- colored eared and cheer pheasants 
 (Crossoptilon auritum and Phasianus wallichii); so that 
 these birds seem conscious that they have little beauty to 
 display. Mr. Bartlett has never seen the males of either of 
 these species fighting together, though he has not had such 
 good opportunities for observing the cheer as the eared 
 pheasant. Mr. Jenner Weir, also, finds that all male 
 birds with rich or strongly-characterized plumage are more 
 quarrelsome than the dull-colored species belonging to the 
 same groups. The goldfinch, for instance, is far more 
 pugnacious than the linnet, and the blackbird than the 
 thrush. Those birds which undergo a seasonal change of 
 plumage likewise become much more pugnacious at the 
 period when they are most gayly ornamented. No doubt 
 the males of some obscurely colored birds fight desperately 
 together, but it appears that when sexual selection has 
 been highly influential, and has given bright colors to the 
 males of any species, it has also very often given a strong 
 tendency to pugnacity. We shall meet with nearly analo- 
 gous cases when we treat of mammals. On the other hand, 
 with birds the power of song and brilliant colors have 
 rarely been both acquired by the males of the same species; 
 but in this case the advantage gained would have been the 
 same, namely, success in charming the female. Neverthe- 
 less it must be owned that the males of several brilliantly 
 colored birds have had their feathers specially modified for 
 the sake of producing instrumental music, though the 
 beauty of this cannot be compared, at least according to 
 our taste, with that of the vocal music of many songsters. 
 
 We will now turn to male birds which are not orna- 
 mented in any high degree, but which nevertheless display
 
 BIRDS. 455 
 
 during their courtship whatever attractions they may pos- 
 sess. These cases are in some respects more curious than 
 the foregoing, and have been but little noticed. I owe the 
 following facts to Mr. Weir, who has long kept confined 
 birds of many kinds, including all the British Fringillidae 
 and Emberizidae. The facts have been selected from a 
 large body of valuable notes kindly sent me by him. The 
 bullfinch makes his advances in front of the female, and 
 then puffs out his breast, so that many more of the crim- 
 son feathers are seen at once than otherwise would be the 
 case. At the same time he twists and bows his black 
 tail from side to side in a ludicrous manner. The male 
 chaffinch also stands in front of the female, thus show- 
 ing his red breast and " blue bell," as the fan- 
 ciers call his head ; the wings at the same time being 
 slightly expanded, with the pure white bands on the shoul- 
 ders thus rendered conspicuous. The common linnet dis- 
 tends his rosy breast, slightly expands his brown wings 
 and tail, so as to make the best of them by exhibiting their 
 white edgings. We must, however, be cautious in conclud- 
 ing that the wings are spread out solely for display, as 
 some birds do so whose wings are not beautiful. This is 
 the case with the domestic cock, but it is always the wing 
 on the side opposite to the female which is expanded, and 
 at the same time scraped on the ground. The male gold- 
 finch behaves differently from all other finches; his wings 
 are beautiful, the shoulders being black, with the dark- 
 tipped wing-feathers spotted with white and edged with 
 golden yellow. When he courts the female he sways his 
 body from side to side, and quickly turns his slightly 
 expanded wings first to one side then to the other with a 
 golden flashing effect. Mr. Weir informs me that no other 
 British finch turns thus from side to side during his court- 
 ship, not even the closely allied male siskin, for he would 
 not thus add to his beauty. 
 
 Most of the British buntings are plain-colored birds; 
 but in the spring the feathers on the head of the male 
 reed-bunting (Emberiza schoeniculus) acquire a fine black 
 color by the abrasion of the dusky tips; and these are 
 erected during the act of courtship. Mr. Weir has kept 
 two species of Amadina from Australia; the A. castanotis 
 is a very small and chastely colored finch, with a dark tail, 
 white rump and jet-black upper tail coverts, each of the
 
 456 THE DESCENT OF MAN. 
 
 "\atter being marked with three large conspicuous oval 
 spots of Avhite.* This species when courting the female 
 slightly spreads out and vibrates these parti-colored tail 
 coverts in a very peculiar manner. The male Amadina 
 Latliami behaves very differently, exhibiting before the 
 female his brilliant!/ spotted breast, scarlet rump and 
 scarlet upper tail coverts. I may here add from Dr. 
 Jerdon that the Indian bulbul (Pycnonotus licBinorrhous) 
 has its under tail coverts of a crimson color, and these, it 
 might be thought, could never be well exhibited; but the 
 bird " when excited often spreads them out laterally so 
 that they can be seen even from above, "f The crimson 
 under tail coverts of some other birds, as with one of the 
 woodpeckers, Picus major, can be seen without any such 
 display. The common pigeon has iridescent feathers on 
 the breast, and every one must have seen how the male 
 inflates his breast while courting the female, thus showing 
 them off to the best advantage. One of the beautiful 
 bronze- winged pigeons of Australia (Ocypliaps lophotes) 
 behaves, as described to me by Mr. AVeir, very differently. 
 The male while standing before the female lowers his head 
 almost to the ground, spreads out and raises his tail and 
 half expands his wings. He then alternately and slowly 
 raises and depresses his body, so that the iridescent 
 metallic feathers are all seen at once and glitter in the sun. 
 
 Sufficient facts have now been given to show with what 
 care male birds display their various charms, and this they 
 do with the utmost skill. While preening their feathers 
 they have frequent opportunities .for admiring themselves 
 and of studying how best to exhibit their beauty. But as 
 all the males of the same species display themselves in 
 exactly the same manner it appears that actions, at first 
 perhaps intentional, have become instinctive. If so, we 
 ought not to accuse birds of conscious vanity; yet when 
 we see a peacock strutting about with expanded and 
 quivering tail feathers he seems the very emblem of pride 
 and vanity. 
 
 The various ornaments possessed by the males are cer- 
 tainly of the highest importance to them, for in some cases 
 
 * For the description of these birds see Gould's " Hand-book to the 
 Birds of Australia," vol. i, 1865, p. 417. 
 f " Buds of India," vol. ii, p, 96.
 
 BIRDS. 45? 
 
 they have been acquired at the expense of greatly impeded 
 powers of flight or of running. The African night-jar 
 (Cosmetornis), which during the pairing-season has one of 
 its primary wing- feathers developed into a streamer of very 
 great length, is thereby much retarded in its flight, 
 although at other times remarkable for its swiftness. The 
 "unwieldy size" of the secondary wing-feathers of the 
 male Argus pheasant is said "almost entirely to deprive 
 the bird of flight." The fine plumes of male birds of para- 
 dise trouble them during a high wind. The extremely long 
 tail-feathers of the male widow-birds (Vidua) of South- 
 ern Africa render " their flight heavy;" but as soon as these 
 are cast off they fly as well as the females. As birds always 
 breed when food is abundant, the males probably do not 
 suffer much inconvenience in searching for food from their 
 impeded powers of movement; but there can hardly be a 
 doubt that they must be much more liable to be struck 
 down by birds of prey. Nor can we doubt that the long 
 train of the peacock and the long tail and wing feathers of 
 the Argus pheasant must render them an easier prey to any 
 prowling tiger-cat than would otherwise be the case. Even 
 the bright colors of many male birds cannot fail to make 
 them conspicuous to their enemies of all kinds. Hence, 
 as Mr. Gould has remarked, it probably is that such birds 
 are generally of a shy disposition, as if conscious that their 
 beauty was a source of danger, and are much more difficult 
 to discover or approach than the somber colored and com- 
 paratively tame females or than the young and as yet 
 unadorned males.* 
 
 It is a more curious fact that the males of some birds 
 which are provided with special weapons for battle, and 
 which in a state of nature are so pugnacious that they 
 often kill each other, suffer from possessing certain orna- 
 ments. Cock-fighters trim the hackles and cut off the 
 combs and gills of their cocks; and the birds are then said 
 to be dubbed. An undubbed bird, as Mr. Tegetmeier 
 
 *0n the Cosraetornis, see Livingstone's "Expedition to the Zam- 
 besi," 1865, p. 66. On the Argus pheasant, Jardine's " Nat. Hist. 
 Lib.: Birds," vol. xiv, p. 167. On birds of paradise, Lesson, quoted 
 by Brehffl, " Thierleben," B. iii, s. 325. On the widow-bird, Bar- 
 row's "Travels in Africa," vol. i, p. 243, and "Ibis," vol. iii, 1861, 
 p. 133. Mr. Gould, on the shyness of male birds, "Hand-book to 
 Birds of Australia," vol. i, 1865, pp. 210, 457.
 
 458 THE DESCENT OF MAN. 
 
 insists, "is at a fearful disadvantage; the comb and gills 
 offer an easy hold to his adversary's beak, and as a cock 
 always strikes where he holds, when once he has seized his 
 foe, he has him entirely in his power. Even supposing 
 that the bird is not killed, the loss of blood suffered by an 
 undubbed cock is much greater than that sustained by one 
 that has been trimmed."* Young turkey-cocks in fighting 
 always seize hold of each other's wattles; and I presume 
 that the old birds fight in the same manner. It may per- 
 haps be objected that the comb and wattles are not orna- 
 mental and cannot be of service to the birds in this way; 
 but even to our eyes the beauty of the glossy black Spanish 
 cock is much enhanced by his white face and crimson 
 comb; and no one who has ever seen the splended blue 
 wattles of the male Tragopan pheasant distended in court- 
 ship can for a moment doubt that beauty is the object 
 gained. From the foregoing facts we clearly see that the 
 plumes and other ornaments of the males must be of the 
 highest importance to them; and we further see that beauty 
 is even sometimes more important than success in battle. 
 
 *Tegetnieier, " The Poultry Book," 1866, p. 139.
 
 BIRDS. 459 
 
 CHAPTER XIV. 
 
 BIRDS continued. 
 
 Choice exerted by the female Length of courtship Unpaired birds 
 Mental qualities and taste for the beautiful Preference or 
 antipathy shown by the female for particular males Variability 
 of birds Variations sometimes abrupt Laws of variation 
 Formation of ocelli Gradations of character Case of peacock, 
 Argus pheasant and Urosticte. 
 
 WHEN the sexes differ in beauty or in the power of sing- 
 ing, or in producing what I have called instrumental 
 music, it is almost invariably the male who surpasses the 
 female. These qualities, as we have just seen, are evidently 
 of high importance to the male. When they are gained 
 for only a part of the year it is always before the breeding- 
 season. It is the male alone who elaborately displays his 
 varied attractions, and often performs strange antics on the 
 ground or in the air, in the presence of the female. Each 
 male drives away, or, if he can, kills his rivals. Hence we 
 may conclude that it is the object of the male to induce 
 the female to pair with him, and for this purpose he tries 
 to excite or charm her in various Avays; and this is the 
 opinion of all those who have carefully studied the habits 
 of living birds. But there remains a question which has 
 an all-important bearing on sexual selection, namely, does 
 every male of the same species excite and attract the 
 female equally? Or does she exert a choice and prefer 
 certain males? This latter question can be answered in the 
 affirmative by much direct and indirect evidence. It is far 
 more difficult to decide what qualities determine the choice 
 of the females; but here again we have some direct and 
 indirect evidence that it is to a large extent the external 
 attractions of the male; though no doubt his vigor, cour- 
 age, and other mental qualities come into play. We will 
 begin with the indirect evidence.
 
 460 THE DESCENT OF MAN. 
 
 Length of Courtship). The lengthened period during 
 which both sexes of certain birds meet day after day at an 
 appointed place probably depends partly on the courtship 
 being a prolonged affair, and partly on reiteration in the 
 act of pairing. Thus in Germany and Scandinavia the 
 balzing or leks of the black-cocks last from the middle of 
 March all through April into May. As many as forty or 
 fifty or even more birds congregate at the leks; and the 
 same place is often frequented during successive years. The 
 lek of the capercailzie lasts from the end of March to the 
 middle or even end of May. In North America "the 
 partridge dances " of the Tetrao phasianellns " last for a 
 month or more." Other kinds of grouse, both in North 
 America and Eastern Siberia,* follow nearly the same 
 habits. The fowlers discover the hillocks where the ruffs 
 congregate by the grass being trampled bare, and this shows 
 that the same spot is long frequented. The Indians of 
 Guiana are well acquainted with the cleared arenas, where 
 they expect to find the beautiful cocks of the rock; and 
 the natives of New Guinea know the trees where from ten 
 to twenty male birds of paradise in full plumage congre- 
 gate. In this latter case it is not expressly stated that the 
 females meet on the same trees, but the hunters, if not 
 specially asked, would probably not mention their presence, 
 as their skins are valueless. Small parties of an African 
 weaver (Ploceus) congregate, during the breeding-season, 
 and perform for hours their graceful evolutions. Large 
 numbers of the solitary snipe (Scolopax major] assemble 
 during dusk in a morass; and the same place is frequented 
 for the same purpose during successive years; here they 
 may be seen running about "like so many large rats/' 
 puffing out their feathers, flapping their wings, and 
 uttering the strangest cries, f 
 
 *Nordman describes ("Bull. Soc. Imp. des Nat. Moscou," 1861, 
 torn, xxxiv, p. 264) the balzen of Tetrao urogalloides in Amur Land. 
 He estimated the number of birds assembled at above a hundred, not 
 counting the females, which lie hid in the surrounding bushes. The 
 noises uttered differ from those of T. urogallus. 
 
 \ With respect to the assemblages of the above-named grouse, see 
 Brehm, "Thierleben," B. iv, s. 350; also L. Lloyd, "Game Birds of 
 Sweden," 1867, pp. 19, 78. Richardson, " Fauna Bor. Americana.: 
 Birds," p. 362. References in regard to the assemblages of other 
 birds have already been given. On Paradisea, see Wallace, in 
 "Annals and Mag. of Nat. Hist.," vol. xx, 1857, p. 412. On the snipe, 
 Lloyd, ibid, p. 221.
 
 BIRDS. 461 
 
 Some of the above birds the black-cock, capercailzie, 
 pheasant-grouse, ruff, solitary snipe, and perhaps others 
 are, as is believed, polygamists. With such birds it might 
 have been thought that the stronger males would simply 
 have driven away the weaker, and then at once have taken 
 possession of as many females as possible; but if it be indis- 
 pensable for the male to excite or please the female, we can 
 understand the length of the courtship and the congrega- 
 tion of so many individuals of both sexes at the same spot. 
 Certain strictly monogamous species likewise hold nuptial 
 assemblages; this seems to be the case in Scandinavia with 
 one of the ptarmigans, and their leks last from the middle 
 of March to the middle of May. In Australia the lyre- 
 birds (Menura superba) forms ie small round hillocks/' and 
 the M. Alberti scratches for itself shallow holes, or, as they 
 are called by the natives, corroborying places, where it is 
 believed both sexes assemble. The meetings of the M. 
 superba are sometimes very large; and an account has 
 lately been published * by a traveler, who heard in a valley 
 beneath him, thickly covered with scrub, "a din which 
 completely astonished " him ; on crawling onward he 
 beheld, to his amazement, about one hundred and fifty of 
 the magnificent lyre-cocks " ranged in order of battle 
 and fighting with indescribable fury." The bowers of the 
 bower-birds are the resort of both sexes during the breed- 
 ing-season; and "here the males meet and contend with 
 each other for the favors of the female, and here the latter 
 assemble and coquet with the males." With two of the 
 genera, the same bower is resorted to during many years.f 
 The common magpie (Corvus pica. Linn.), as I have 
 been informed by the Kev. W. Darwin Fox, used to 
 assemble from all parts of Delamere forest, in order to 
 celebrate the "great magpie marriage." Some years ago 
 these birds abounded in extraordinary numbers, so that ,a 
 gamekeeper killed in one morning nineteen males, and 
 another killed by a single shot seven birds at roost together. 
 They then had the habit of assembling very early in the 
 spring at particular spots, where they could be seen in 
 
 * Qudled by Mr. T, W Wood in the " Student," April, 1870, p. 
 125. 
 
 f Gould, " Hand-book to the Birds of Australia," vol. i, pp. 300, 
 308, 448, 451. On the ptarmigan, above alluded to, see Lloyd, ibid, 
 p. 139.
 
 462 THE DESCENT OF MAN. 
 
 flocks, chattering, sometimes fighting, bustling and flying 
 about the trees. The whole affair was evidently consid- 
 ered by the birds as one of the highest importance. 
 Shortly after the meeting they all separated, and were then 
 observed by Mr. Fox and others to be paired for the 
 season. In any district in which a species does not exist in 
 large numbers great assemblages cannot, of course, be 
 held, and the same species may have different habits in dif- 
 ferent countries. For example, I have heard of only one 
 instance, from Mr. Wedderburn, of a regular assemblage 
 of black game in Scotland, yet these assemblages are so 
 well known in Germany and Scandinavia that they have 
 received special names. 
 
 Unpaired Birds. From the facts now given, we may 
 conclude that the courtship of birds belonging to widely 
 different groups is often a prolonged, delicate, and trouble- 
 some affair. There is even reason to suspect, improbable as 
 this will at first appear, that some males and females of the 
 same species, inhabiting the same district, do not always 
 please each other, and consequently do not pair. Many 
 accounts have been published of either the male or female 
 of a pair having been shot and quickly replaced by 
 another. This has been observed more frequently with 
 the magpie than with any other bird, owing, perhaps, 
 to its conspicuous appearance and nest. The illustrious 
 Jenner states that in Wiltshire one of a pair was daily shot 
 no less than seven times successively, " but all to no pur- 
 pose, for the remaining magpie soon found another mate;" 
 and the last pair reared their young. A new partner is 
 generally found on the succeeding day ; but Mr. Thomp- 
 son gives the case of one being replaced on the 
 evening of the same day. Even after the eggs are hatched, 
 if one of the old birds is destroyed a mate will often be 
 found; this occurred after an interval of two days in a case 
 recently observed by one of Sir J. Lubbock's keepers.* 
 The first and most obvious conjecture is that male magpies 
 must be much more numerous than females; and that in the 
 above cases, as well as in many others which could be given, 
 the males alone had been killed. This apparently holds 
 
 *0n magpies, Jenner, in "Phil. Transact.," 1824, p. 21. Macgil- 
 livray, " Hist. British Birds," vol. i, p. 670. Thompson, in "Annals 
 and Mag. of Nat. Hist.," vol. viii, 1842, p 494.
 
 BIRDS. 463 
 
 good in some instances, for the gamekeepers in Delamere 
 forest assured Mr. Fox that the magpies and carrion-crows 
 which they formerly killed in succession in large numbers 
 near their nests were all males; and they accounted for this 
 fact by the males being easily killed while bringing food to 
 the sitting females. Macgillivray, however, gives, on the 
 authority of an excellent observer, an instance of three mag- 
 pies successively killed on the same nest, which were all 
 females; and another case of six magpies successively killed 
 while sitting on the same eggs, which renders it probable 
 that most of them were females; though, as I hear from 
 Mr. Fox, the male will sit on the eggs when the female is 
 killed. 
 
 Sir' J. Lubbock's gamekeeper has repeatedly shot, but 
 how often he could not say, one of a pair of jays (Garrulus 
 ylamlftrius), and has never failed shortly afterward to find 
 the survivor rematched. Mr. Fox, Mr. F. Bond and others 
 have shot one of a pair of carrion-crows (Corvus corotie), but 
 the nest was soon again tenanted by a pair. These birds 
 are rather common; but the peregrine-falcon (Falcopere- 
 grinus) is rare, yet Mr. Thompson states that in Ireland " if 
 either an old male or female be killed in the breeding- 
 season (not an uncommon circumstance) another mate 
 is found within a very few days, so that the eyries, not- 
 withstanding such casualties, are sure to turn out their 
 complement of young." Mr. Jenner "Weir has known the 
 same thing with the peregrine-falcons at Beachy Head. 
 The same observer informs me that three kestrels (Falco 
 tinnunculiis), all males, were killed, one after the other, 
 while attending the same nest; two of these were in mature 
 plumage, but the third was in the plumage of the previous 
 year. Even with the rare golden eagle (Aquila chrysaetos}, 
 Mr. Birkbeck was assured by a trustworthy gamekeeper in 
 Scotland, that if one is killed another is soon found. So 
 with the white owl (Stnx flammea) " the survivor readily 
 found a mate, and the mischief went on." 
 
 White of Selborne, who gives the case of the owl, adds 
 that he knew a man, who, from believing that partridges 
 when paired were disturbed by the males fighting, used to 
 shoot hem; and though he had widoAved the same female 
 several times, she always soon found a fresh partner. This 
 same naturalist ordered the sparrows, which deprived the 
 house-martins of their nests, to be shot; but the one which
 
 464 THE DESCENT OF MAN. 
 
 was left, "be it cock or hen, presently procured a mate, 
 and so for several times following." I could add analogous 
 cases relating to the chaffinch, nightingale and redstart. 
 With respect to the latter bird (Phcenicura ruticilla), a 
 writer expresses much surprise how the sitting female could 
 so soon have given effectual notice that she was a widow, for 
 the species was not common in the neighborhood. Mr. Jenner 
 Weir has mentioned to me a nearly similar case: at Blackheath 
 he never sees or hears the note of the wild bullfinch, yet 
 when one of his caged males has died a wild one in the 
 course of a few days has generally come and perched near 
 the widowed female, whose call-note is not loud. I will 
 give only one other fact, on the authority of this same 
 observer; one of a pair of starlings (Sturmis vulyari*) was 
 shot in the morning; by noon a new mate was found; this 
 was again shot, but before night the pair was complete; so 
 that the disconsolate widow or widower was thrice consoled 
 during the same day. Mr. Engleheart also informs me 
 that he used during several years to shoot one of a pair of 
 starlings which built in a hole in a house at Blackheath; 
 but the loss was always immediately repaired. During one 
 season he kept an account, and found that he had shot 
 thirty-five birds from the same nest; these consisted of 
 both males and females, but in what proportion he could 
 not say; nevertheless, after all this destruction, a brood was 
 reared.* 
 
 These facts well deserve attention. How is it that there 
 are birds enough ready to replace immediately a lost mate 
 of either sex? Magpies, jays, carrion-crows, partridges, 
 and some other birds are always seen during the spring in 
 pairs, and never by themselves; and these offer at first sight 
 the most perplexing cases. But birds of the same sex, 
 although of course not truly paired, sometimes live in pairs 
 or in small parties, as is known to be the case with pigeons 
 and partridges. Birds also sometimes live in triplets, as 
 has been observed with starlings, carrion-crows, parrots 
 and partridges. With partridges two females have been 
 
 *0n the peregrine falcon, see Thompson, "Nat. Hist, of Ireland- 
 Birds," vol. i, 1849, p. 39. On owls, sparrows and partridges, see 
 White, "Nat. Hist, of Selborne," edit, of 1825, vol. i, p. 139. On 
 the Phoenicura, see London's " Mag. of Nat. Hist.," vol. vii, 1834, p. 
 245. Brehin (" Thierleben," B. iv, s. 991) also alludes to cases of 
 birds thrice mated during the same day.
 
 BIRDS. 465 
 
 known to live with one male, and two males with one 
 female. In all such cases it is probable that the union 
 would be easily broken; and one of the three would readily 
 pair with a widow or widower. The males of certain birds 
 may occasionally be heard pouring forth their love-song 
 long after the proper time, showing that they have either 
 lost or never gained a mate. Deatli from accident or dis- 
 ease of one of a pair would leave the other free and single; 
 and there is reason to believe that female birds during the 
 breeding-season are especially liable to premature death. 
 Again, birds which have had their nests destroyed, or 
 barren pairs, or retarded individuals, would easily be 
 induced to desert their mates, and would probably be glad 
 to take what share they could of the pleasures and duties 
 of rearing offspring, although not their own.* Such con- 
 tingencies as these probably explain most of the foregoing 
 cases, f Nevertheless, it is a strange fact that within the 
 same district, during the height of the breeding-season, 
 there should be so many males and females always ready to 
 repair the loss of a mated bird. Why do not such spare 
 birds immediately pair together? Have we not some reason 
 to suspect, and the suspicion has occurred to Mr. Jenner 
 Weir, that, as the courtship of birds appears to be in many 
 
 * See White (" Nat. Hist, of Selborne," 1825, vol. i, p. 140) on the 
 existence, early in the season, of small coveys of male partridges, of 
 which fact I have heard other instances. See Jenner, on the retarded 
 state of the generative organs in certain birds, in "Phil. Transact." 
 1824. In regard to birds living in triplets, I owe to Mr. Jenner Weir 
 the cases of the starlings and parrots, and to Mr. Fox, of partridges; 
 on carrion-crows, see the " Field," 1868, p. 415. On various male 
 birds singing after the proper period, see Rev. L. Jenyns, "Ob- 
 servations in Natural History," 1846, p. 87. 
 
 f-The following case has been given ("The Times," Aug. 6, 1868) 
 by the Rev. F. 0. Morris, on the authority of the Hon. and Rev. O. 
 W. Forester. " The gamekeeper here found a hawk's nest this year 
 
 with five young ones in it. He took four and killed them, but left 
 one with its wings clipped as a decoy to destroy the old ones by. 
 They were both shot next day in the act of feeding the young one, 
 and the keeper thought it was done with. The next day he came 
 again and found two other charitable hawks who had come with an 
 adopted feeling to succor the orphan. These two he killed and then 
 left thejiest. On returning afterward he found two more charitable 
 individuals on the same errand of mercy. One of these he killed; 
 the other he also shot but could not find. No more came on the lika 
 fruitless errand."
 
 466 THE DESCENT OF MAN. 
 
 cases prolonged and tedious, so it occasionally happens that 
 certain males and females do not succeed, during the proper 
 season, in exciting each other's love, and consequently do 
 not pair? This suspicion will appear somewhat less improba- 
 ble after we have seen what strong antipathies and prefer- 
 ences female birds occasionally evince toward particular 
 males. 
 
 Mental Qualities of Birds and Tfietr Taste for the 
 Beautiful. Before we further discuss the question whether 
 the females select the more attractive males or accept the 
 first whom they may encounter, it will be advisable briefly 
 to consider the mental powers of birds. Their reason is 
 generally, and perhaps justly, ranked as low; yet some facts 
 could be given* leading to an opposite conclusion. Low 
 powers of reasoning, however, are compatible, as we see 
 with mankind, with strong affections, acute perception, 
 and a taste for the beautiful; and it is with these latter 
 qualities that we are here concerned. It has often been 
 said that parrots become so deeply attached to each other 
 that when one dies the other pines for a long time; but 
 Mr. Jenner Weir thinks that with most birds the strength 
 of their affection has been much exaggerated. Neverthe- 
 less, when one of a pair in a state of nature has been shot, 
 the survivor has been heard for days afterward uttering a 
 plaintive call; and Mr. St. John gives various facts proving 
 the attachment of mated birds, f Mr. Bennett relates}; that 
 in China after a drake of the beautiful mandarin teal had 
 been stolen the duck remained disconsolate, though sedu- 
 lously courted by another mandarin drake, who displayed 
 
 * I am indebted to Prof. Newton for the following passage from 
 Mr. Adam's "Travels of a Naturalist," 1870, p. 278. Speaking of 
 Japanese nut-hatches in confinement, he says: " Instead of the more 
 yielding fruit of the yew, which is the usual food of the nut-hatch 
 of Japan, at one time I substituted hard hazel-nuts. As the bird 
 was unable to crack them, he placed them one by one in his water- 
 glass, evidently with the notion that they would in time become 
 softer an interesting proof of intelligence on the part of these 
 birds." 
 
 f'A Tour in Sutherlandshire," vol. i, 1849, p. 185. Dr. Buller 
 says ("Birds of New Zealand," 1872, p. 56) that a male King Lory 
 was killed; and the female "fretted and moped, refused her food, 
 and died of a broken heart." 
 
 J " Wanderings in New South Wales," vol. ii, 1834, p. 62.
 
 BIRDS. 467 
 
 before her all his charms. After an interval of three weeks 
 the stolen drake was recovered, and instantly the pair 
 recognized each other with extreme joy. On the other 
 hand starlings, as we have seen, may be consoled thrice in 
 the same day for the loss of their mates. Pigeons have 
 such excellent local memories that they have been known 
 to return to their former homes after an interval of nine 
 months, yet, as I hear from Mr. Harrison Weir, if a pair 
 which naturally would remain mated for life be separated 
 for a few weeks during the winter, and afterward matched 
 with other birds, the two, when brought together again, 
 rarely, if ever, recognize each other. 
 
 Birds sometimes exhibit benevolent feelings; they will 
 feed the deserted young ones even of distinct species, but 
 this perhaps ought to be considered as a mistaken instinct. 
 They will feed, as shown in an earlier part of this work, 
 adult birds of their own species which have become blind. 
 Mr. Buxton gives a curious account of a parrot which took 
 care of a frost-bitten and crippled bird of a distinct species, 
 cleansed her feathers and defended her from the attacks of 
 the other parrots which roamed freely about his garden. 
 It is a still more curious fact that these birds apparently 
 evince some sympathy for the pleasures of their fellows. 
 When a pair of cockatoos made a nest in an acacia tree " it 
 was ridiculous to see the extravagant interest taken in the 
 matter by the others of the same species. These parrots 
 also evinced unbounded curiosity and clearly had " the 
 idea of property and possession/'* They have good mem- 
 ories, for in the Zoological Gardens they have plainly 
 recognized their former masters after an interval of some 
 months. 
 
 Birds possess acute powers of observation. Every mated 
 bird, of course, recognizes its fellow. Audubon states that 
 a certain number of mocking-thrushes (Mimus polyglottus) 
 remain all the year round in Louisiana, while others 
 migrate to the Eastern States; these latter on their return 
 are instantly recognized and always attacked by their 
 southern brethren. Birds under confinement distinguish 
 different persons, as is proved by the strong and permanent 
 antipathy or affection which they show without any appar- 
 
 * " Acclimatization of Parrots," by C. Buxton, M. P. "Annals and 
 Mag. of Nat. Hist.," Nov., 1868, p. "381.
 
 468 THB DESCENT OF MAN. 
 
 ent cause toward certain individuals. -I have heard of 
 numerous instances with jays, partridges, canaries, and 
 especially bullfinches. Mr. Hussey has described in how 
 extraordinary a manner a tamed partridge recognized 
 everybody; and its likes and dislikes were very strong. 
 This bird seemed "fond of gay colors, and no new gown 
 or cap could be put on without catching his attention."* 
 Mr. Hewitt has described the habits of some ducks 
 (recently descended from wild birds) which at the approach 
 of a strange dog or cat would rush headlong into the water 
 and exhaust themselves in their attempts to escape; but 
 they knew Mr. Hewitt's own dogs and cats so well that 
 they would lie down and bask in the sun close to them. 
 They always moved away from a strange man, and so they 
 would from the lady who attended them if she made any 
 great change in her dress. Audubon relates that he reared 
 and tamed a wild turkey which always ran away from any 
 strange dog; this bird escaped into the woods, and some 
 days afterward Audubon saw, as he thought, a wild turkey 
 and made his dog chase it; but to his astonishment the 
 bird did not run away, and the dog when he came up did 
 not attack the bird, for they mutually recognized each 
 other as old friends, f 
 
 Mr. Jenner Weir is convinced that birds pay particular 
 attention to the colors of other birds, sometimes out of 
 jealousy and sometimes as a sign of kinship. Thus he 
 turned a reed-bunting (Eniberiza sclmniculus), which had 
 acquired its black head-dress, into his aviary, and the new- 
 comer was not noticed by any bird except by a bullfinch, 
 which is likewise black-headed. This bullfinch was a very 
 quiet bird, and had never before quarreled with any of its 
 comrades, including another reed-bunting, which had not 
 as yet become black-headed ; but the reed-bunting with a 
 black head was so unmercifully treated that it had to be 
 removed. Spiza cyanea, during the breeding-season, is of 
 a bright blue color; and though generally peaceable, it 
 attacked 8. ciris, which has only the head blue, and com- 
 pletely scalped the unfortunate bird. Mr. Weir was also 
 
 * " The Zoologist," 1847-1848, p. 1602. 
 
 f Hewitt on wild ducks, " Journal of Horticulture," Jan. 13, 1863, 
 
 ?. 39. Audubon on the wild turkey, "Ornith. Biography," vol. i, p. 
 4. On the mocking-thrush, ibid, vol. i, p. 110.
 
 BIRDS. 469 
 
 obliged to turn out a robin, as it fiercely attacked all the 
 birds in his aviary with any red in their plumage, but no 
 other kinds; it actually killed a red-brested crossbill and 
 nearly killed a goldfinch. On the other hand, he has 
 observed that some birds, when first introduced, fly toward 
 the species which resemble them most in color, and settle 
 by their sides. 
 
 As male birds display their fine plumage and other orna- 
 ments with so much care before the females, it is obvi- 
 ously probable that these appreciate the beauty of their 
 suitors. It is, however, difficult to obtain direct evidence 
 of their capacity to appreciate beauty. When birds gaze 
 at themselves in a looking-glass (of which many instances 
 have been recorded) we cannot feel sure that it is not from 
 jealousy of a supposed rival, though this is not the conclu- 
 sion of some observers. In other cases it is difficult to dis- 
 tinguish between mere curiosity and admiration. It is 
 perhaps the former feeling which, as stated by Lord Lil- 
 ford,* attracts the ruff toward any bright object, so that, 
 in the Ionian Islands, " it will dart down to a bright-col- 
 ored handkerchief, regardless of repeated shots." The 
 common lark is drawn down from the sky, and is caught 
 in large numbers, by a small mirror made to move and 
 glitter in the sun. Is it admiration or curiosity which 
 leads the magpie, raven, and some other birds to steal and 
 secrete bright objects, such as silver articles or jewels? 
 
 Mr. Gould states that certain humming-birds decorate 
 the outsides of their nests " with the utmost taste ; they 
 instinctively fasten thereon beautiful pieces of flat lichen, 
 the larger pieces in the middle, and the smaller on the part 
 attached to the branch. Now and then a pretty feather 
 is intertwined or fastened to the outer sides, the stem being 
 always so placed that the feather stands out beyond the. 
 surface." The best evidence, however, of a taste for the 
 beautiful is afforded by the three genera of Australian 
 bower-birds already mentioned. Their bowers (see fig. 46), 
 where the sexes congregate and play strange antics, 
 are variously constructed, but what most concerns us is, 
 that they are decorated by the several species in a different 
 manner". The satin bower-bird collects gayly-colored arti- 
 cles, such as the blue tail-feathers of paroquets, bleached 
 
 The "Ibis," vol. ii, I860, p. 344.
 
 470 THE DESCENT OF MAN. 
 
 bones and shells, which it sticks between the twigs 01 
 arranges at the entrance. Mr. Gould found in one bowel 
 a neatly- worked stone tomahawk and a slip of blue cotton, 
 evidently procured from a native encampment. These 
 objects are continually rearranged, and carried about by 
 the birds while at play. The bower of the spotted bower- 
 bird " is beautifully lined with tall grasses, so disposed that 
 the heads nearly meet, and the decorations are very profuse." 
 Round stones are used to keep the grass-stems in their 
 proper places and to make divergent paths leading to the 
 bower. The stones and shells are often brought from a 
 great distance. The regent bird, as described by Mr. 
 Ramsay, ornaments its short bower with bleached land- 
 shells belonging to five or six species, and with "berries of 
 various colors, blue, red, and black, which give it when 
 fresh a very pretty appearance. Besides these there were 
 several newly-picked leaves and young shoots of a pinkish 
 co_lor, the whole showing a decided taste for the beautiful." 
 Well may Mr. Gould say that " these highly decorated 
 halls of assembly must be regarded as the most wonderful 
 instances of bird-architecture yet discovered;" and the 
 taste, as we see, of the several species certainly differs.* 
 
 Preference for Particular Males by the Females. Having 
 made these preliminary remarks on the discrimination and 
 taste of birds, I will give all the facts known to me which 
 bear on the preference shown by the female for particular 
 males. It is certain that distinct species of birds occasion- 
 ally pair in a state of nature and produce hybrids. Many 
 instances could be given; thus Macgillivray relates how a 
 male blackbird and female thrush " fell in love with each 
 other," and produced offspring.! Several years ago eight- 
 een cases had been recorded of the occurrence in Great 
 Britain of hybrids between the black grouse and pheasant;^ 
 but most of these cases may perhaps be accounted for by 
 solitary birds not finding one of their own species to pair 
 with. With other birds, as Mr. Jenner Weir has reason to 
 
 * On the ornamental nests of humming-birds, Gould, "Introduc- 
 tion to the Trochilidffi, 1861, p. 19. On the bower-birds, Gould, 
 " Hand-book to the Birds of Australia," 1865, vol. i, pp. 444-461. 
 Ramsay, in the "Ibis," 1867, p. 456. 
 
 f " Hist, of British Birds," vol. ii, p. 92. 
 
 J" Zoologist," 1858-1854, p. 3940.
 
 BIRDS. 471 
 
 believe, hybrids are sometimes the result of the casual inter- 
 course of birds building in close proximity. But these 
 remarks do not apply to the many recorded instances of 
 tamed or domestic birds, belonging to distinct species, 
 which have become absolutely fascinated with each other, 
 although living with their own species. Thus Waterton* 
 states that out of a flock of twenty-three Canada geese, a 
 female paired with a solitary Bernicle gander, although so 
 different in appearance and size; and they produced hybrid 
 offspring. A male wigeon (Mareca penelope) living with 
 females of the same species has been known to pair with a 
 pintail duck, Querquedula acuta. Lloyd describes the re- 
 markable attachment between a shield-drake (Tadorna 
 vulpanser) and a common duck. Many additional instances 
 could be given; and the Rev. E. S. Dixon remarks that 
 " those who have kept many different species of geese 
 together well know what unaccountable attachments they 
 are frequently forming, and that they are quite as likely to 
 pair and rear young with individuals of a race (species) 
 apparently the most alien to themselves as with their own 
 stock." 
 
 The Rev. W. D. Fox informs me that he possessed at the 
 isame time a pair of Chinese geese (Anser Cygnoides) and a 
 common gander with three geese. The two lots kept quite 
 separate, until the Chinese gander seduced one of the 
 common geese to live with him. Moreover, of the young 
 birds hatched from the eggs of the common geese, only 
 four were pure, the other eighteen proving hybrids; so that 
 the Chinese gander seems to have had prepotent charms 
 over the common gander. I will give only one other case: 
 Mr. Hewitt states that a wild duck, reared in captivity, 
 " after breeding a couple of seasons with her own mallard, 
 at once shook him off on my placing a male pintail on the 
 water. It was evidently a case of love at first sight, for 
 she swam about the new-comer caressingly, though he 
 appeared evidently alarmed and averse to her overtures of 
 
 * Waterton, "Essays on Nat. Hist.," 2d series, pp. 42, 117. For 
 the following statements see on the wigeon, Loudon's " Mag. of Nat. 
 Hist.," vol. ix, p. 616. L. Lloyd, " Scandinavian Adventures," vol. i, 
 1854, p'. 452. Dixon, " Ornamental and Domestic Poultry," p. 137; 
 Hewitt, in "Journal of Horticulture," Jan. 13, 1863, p. 40; Bech- 
 stein, " Stubenvogel," 1840, s. 230. Mr. Jenner Weir has lately 
 given me an analogous case with ducks of two species,
 
 472 THE DESCENT OF MAN. 
 
 affection. From that hour she forgot her old partner. 
 Winter passed by, and the next spring the pintail seemed 
 to have become a convert to her blandishments, for they 
 nested and produed seven or eight young ones." 
 
 What the charm may have been in these several cases, 
 beyond mere novelty, we cannot even conjecture. Color, 
 however, sometimes comes into play; for in order to raise 
 hybrids from the siskin (Fringilla spinus) and the canary, 
 it is much the best plan, according to Bechstein, to place 
 birds of the same tint together. Mr. Jenner Weir turned 
 a female canary into his aviary, where there were male 
 linnets, goldfinches, siskins, greenfinches, chaffinches and 
 other birds, in order to see which she would choose; but 
 there never was any doubt, and the greenfinch carried the 
 day. They paired and produced hybrid offspring. 
 
 The fact of the female preferring to pair with one male 
 rather than with another of the same species is not so likely 
 to excite attention as when this occurs, as we have just 
 seen, between distinct species. The former cases can best 
 be observed with domesticated or confined birds; but these 
 are often pampered by high feeding, and sometimes have 
 their instincts vitiated to an extreme degree. Of this latter 
 fact I could give sufficient proofs with pigeons, and espe- 
 cially with fowls, but they cannot be here related. Vitiated 
 instincts may also account for some of the hybrid unions 
 above mentioned; but in many of these cases the birds were 
 allowed to range freely over large ponds, and there is no 
 reason to suppose that they were unnaturally stimulated by 
 high feeding. 
 
 With respect to birds in a state of nature, the first and 
 most obvious supposition which will occur to every one is 
 that the female at the proper season accepts the first male 
 whom she may encounter; but she has at least the oppor- 
 tunity for exerting a choice, as she is almost invariably 
 pursued by many males. Audubon and we must remem- 
 ber that he spent a long life in prowling about the forests 
 of the United States and observing the birds does not 
 doubt that the female deliberately chooses her mate; thus, 
 speaking of a woodpecker, he says the hen is followed by 
 half a dozen gay suitors, who continue performing strange 
 antics, "until a marked preference is shown for one." The 
 female of the red-winged starling (Agelcsus pJiceniccus) is 
 likewise pursued by several males j " until, becoming
 
 BIRDS. 473 
 
 fatigued, she alights, receives their addresses, and soon 
 makes a choice." He describes also how several male 
 night-jars repeatedly plunge through the air with astonish- 
 ing rapidity, suddenly turning, and thus making a singular 
 noise; " but no sooner has the female made her choice than 
 the other males are driven away/' With one of the 
 vultures (Catliartes aura) of the United States, parties of 
 eight, ten, or more males and females assemble on fallen 
 logs > "exhibiting the strongest desire to please mutually," 
 and after many caresses each male leads off his partner on 
 the wing. Audubon likewise carefully observed the wild 
 flocks of Canada geese (Anser canadensis), and gives a 
 graphic description of their love antics; he says that the 
 birds which had been previously mated "renewed their 
 courtship as early as the month of January, while the 
 others would be contending or coquetting for hours every 
 day, until all seemed satisfied with the choice they had 
 made, after which, although they remained together, am 
 person could easily perceive that they were careful to keep 
 in pairs. I have observed also tlmt the older the birds the 
 shorter were the preliminaries of their courtship. The 
 bachelors and old maids, whether in regret or not caring 
 to be disturbed by the bustle, quietly moved aside and lay 
 down at some distance from the rest/'* Many similar 
 statements with respect to other birds could be cited from 
 this same observer. 
 
 Turning now to domesticated and confined birds, I will 
 commence by giving what little I have learned respecting 
 the courtship of f owls c I have recieved long letters on this 
 subject from Messrs. Hewitt and Tegetmeier, and almost 
 an essay from the late Mr. Brent. It will be admitted by 
 every one that these gentlemen, so well known from their 
 published works, are careful and experienced observers. 
 They do not believe that the females prefer certain males 
 on account of the beauty of their plumage; but some allow- 
 ance must be made for the artificial state under which 
 these birds have long been kept. Mr. Tegetmeier is con- 
 vinced that a gamecock, though disfigured by being dubbed 
 and with his hackles trimmed, would be accepted as readily 
 as a male retaining all his natural ornaments. Mr, Brent, 
 
 * Audubon, " Ornitholog. Biography," voL i, pp. 191, 849j vol. iL 
 pp. 42, 275; vol. iii. jk a
 
 474 THE DESCENT OF MAN. 
 
 however, admits that the heauty of the male probably aids 
 in exciting the female; and her acquiescence is necessary. 
 Mr c Hewitt is convinced that the union is by no means left 
 to mere chance, for the female almost invariably prefers 
 the most vigorous, defiant and mettlesome male; hence it 
 is almost useless, as he remarks, " to attempt true breeding 
 if a gamecock in good health and condition runs the local- 
 ity, for almost every hen on leaving the roosting-place will 
 resort to the gamecock, even though that bird may not 
 actually drive away the male of her own variety." Under 
 ordinary circumstances the males and females of the fowl 
 eeem to come to a mutual understanding by means of cer- 
 tain gestures, described to me by Mr. Brent. But hens 
 will often avoid the officious attentions of young males. 
 Old hens and hens of a pugnacious disposition, as the 
 same writer informs me, dislike strange males, and will not 
 yield until well beaten into compliance. Ferguson, how- 
 ever, describes how a quarrelsome hen was subdued by the 
 gentle courtship of a shanghai cock.* 
 
 There is reason to believe that pigeons of both sexes 
 prefer pairing with birds of the same breed; and dove-cote 
 pigeons dislike all the highly improved breeds, f Mr. Har- 
 rison Weir has lately heard from a trustworthy observer 
 who keeps blue pigeons that these drive away all other 
 colored varieties, such as white, red and yellow; and from 
 another observer, that a female dun carrier could not, after 
 repeated trials, be matched with a black male, but imme- 
 diately paired with a dun. Again, Mr. Tegetmeier had a 
 female blue turbit that obstinately refused to pair with two 
 males of the same breed, which were successively shut up 
 with her for weeks; but on being let out she would have 
 immediately accepted the first blue dragon that offered. 
 As she was a valuable bird, she was then shut up for many 
 weeks with a silver (*. e., very pale blue) male, and at last 
 mated with him. Nevertheless, as a general rule, color 
 appears to have little influence on the pairing of pigeons. 
 Mr. Tegetmeier, at my request, stained some of his birds 
 with magenta, but they were not much noticed by the 
 others. 
 
 f "I 
 voiii, 
 
 " Rare and Prize Poultry," 1854, p. 27. 
 
 The Variation of Animals and Plants under Domestication," 
 p. 108.
 
 BIRD 8. 475 
 
 Female pigeons occasionally feel a strong antipathy toward 
 certain males, without any assignable cause. Thus MM. 
 Boitard and Corbie,, whose experience extended over forty- 
 five years, state: " Quand une femelle eprouve de 1'antip- 
 athie pour un male avec lequel on veut 1'accoupler, malgre 
 tous les feux de 1'amour, malgre 1'alpiste et le cheinevis dont 
 on la nourrit pour augmenter son ardeur, malgre un em- 
 prisounement de six mois et mme d'un an, elle refuse con- 
 stamment ses caresses; les avances empressees, les agaceries, 
 les tournoiemens, les tendres roucoulemens, rien ne peut lui 
 plaire ni Pemouvoir ; gonflee, boudeuse, blottie dans un 
 coin de sa prison, elle n'en sort que pour boire et manger, 
 ou pour repousser avec une espece de rage des caresses 
 devenues trop pressantes.*' * On the other hand, Mr. 
 Harrison Weir has himself observed and has heard from 
 several breeders, that a female pigeon will occasionally take 
 a strong 'fancy for a particular male, and will desert her 
 own mate for him, Some females, according to another 
 experienced observer, Riedel,f are of a profligate disposi- 
 tion, and prefer almost any stranger to their own mate. 
 Some amorous males, called by our English fanciers " gay 
 birds," are so successful in their gallantries that, as Mr. H. 
 Weir informs me, they must be shut up on account of the 
 mischief which they cause. 
 
 Wild turkeys in the United States, according to Audu- 
 bon, " sometimes pay their addresses to the domesticated 
 females, and are generally received by them with great 
 pleasure." So that these females apparently prefer the 
 wild to their own males. J 
 
 Here is a more curious case^ Sir E. Heron during many 
 years kept an account of the habits of the pea-fowl, which 
 he bred in large numbers. He states that '' the hens have 
 frequently great preference to a particular peacock. They 
 were all so fond of an old pied cock that one year, when he 
 was confined, though still in view, they were constantly 
 assembled close to the trellised-walls of his prison, and would 
 
 * Boitard and Corbie, "Les Pigeons, etc.," 1824, p. 12. Prosper 
 Lucas ("Traite de 1'Hered. Nat.," torn, ii, 1850, p. 296) has himself 
 observed nearly similar facts with pigeons. 
 
 f"Die Taubenzucht,'-' 1824, s. 86, 
 
 J "Ornithological Biography," vol. i, p. 13. See to the same 
 effect. Dr. Bryant, in "Allen's Mammals and Birds of Florida," p.
 
 476 THE DESCENT OF MAN. 
 
 not suffer a japanned peacock to touch them. On his being 
 let out in the autumn, the oldest of the hens instantly 
 courted him and was successful in her courtship. The next 
 year he was shut up in a stable, and then the hens all 
 courted his rival."* This rival was a japanned or black- 
 winged peacock, to our eyes a more beautiful bird than the 
 common kind. 
 
 Lichtenstein, who was a good observer and had excellent 
 opportunities of observation at the Cape of Good Hope, 
 assured Rudolphi that the female widow -bird (Chera 
 progne) disowns the male when robbed of the long tail 
 feathers with which he is ornamented during the breeding- 
 season. I presume that this observation must have been 
 made on birds under confinement, f Here is an analogous 
 case: Dr. Jaeger, J director of the Zoological Gardens of 
 Vienna, states that a male silver-pheasant who had been 
 triumphant over all other males and was the accepted lover 
 of the females had his ornamental plumage spoiled. He 
 was then immediately superseded by a rival who got the 
 upper hand and afterward led the flock. * 
 
 It is a remarkable fact, as showing how important cojor 
 is in the courtship of birds, that Mr. Boardman, a well- 
 known collector and observer of birds for many years in 
 the Northern United States, has never in his large experi- 
 ence seen an albino paired with another bird; yet he has 
 had opportunities of observing many albinos belonging to 
 several species. It can hardly be maintained that albinos 
 in a state of nature are incapable of breeding, as they can 
 be raised with the greatest facility under confinement. It 
 appears, therefore, that we must attribute the fact that 
 they do not pair to their rejection by their normally colored 
 comrades. 
 
 Female birds not only exert a choice, but in some few 
 
 *"Proc. Zool. Soc.," 1835, p. 54. The japanned peacock is con- 
 sidered by Mr. Sclater as a distinct species, and has been named 
 Pavo nigripennis; but the evidence seems to me to show that it is 
 only a variety. 
 
 fRudolphi, " Beytrage ziir Anthropologie," 1812, s. 184. 
 
 j " Die Darwin'sche Theorie, und ihre Stellung zu Moral und 
 Religion," 1869, s. 59. 
 
 SThis statement is given by Mr. A. Leith Adams, in his "Field 
 and Forest K*mbles," 1878>" p. 76, wad awrds with hie owji
 
 BIRDS. 477 
 
 cases they court the male, or even fight together for his 
 possession. Sir E. Heron states that with peafowl the first 
 advances are always made by the female; something of the 
 same kind takes place, according to Audubon, with the 
 older females of the wild turkey. With the capercailzie, 
 the females flit round the male while he is parading at one 
 of the places of assemblage and solicit his attention.* We 
 have seen that a tame wild duck seduced an unwilling pin- 
 tail drake after a long courtship. Mr. Bartlett believes 
 that the Lophophoms, like many other gallinaceous birds, 
 is naturally polygamous, but two females cannot be placed 
 in the same cage with a male as they fight so much 
 together. The following instance of rivalry is more sur- 
 prising as it relates to bullfinches, which usually pair for 
 life. Mr. Jenner Weir introduced a dull-colored and ugly 
 female into his aviary and she immediately attacked 
 another mated female so unmercifully that the latter had 
 to be separated. The new female did all the courtship, 
 and was at last successful, for she paired with the male; 
 but after a time ^he met with a just retribution, for, ceas- 
 ing to be pugnacious, she was replaced by the old female, 
 and the male then deserted his new and returned to his old 
 love. 
 
 In all ordinary cases the male is so eager that he will 
 accept any female, and does not, as far as we can judge, 
 prefer one to the other ; but, as we shall hereafter see, 
 exceptions to this rule apparently occur in some few 
 groups. With domesticated birds I have heard of only one 
 case of males showing any preference for certain females, 
 namely, that of the domestic cock, who, according to the 
 high authority of Mr. Hewitt, prefers the younger to the 
 older hens. On the other hand, in effecting hybrid unions 
 between the male pheasant and common hens, Mr. Hewitt is 
 convinced that the pheasant invariably prefers the older 
 birds. He does not appear to be in the least influenced by 
 their color; but " is most capricious in his attachments;" f 
 from some inexplicable cause he shows the most determined 
 
 *In regard to peafowl, see Sir R. Heron, "Proc. Zoolog. Soc.," 
 1835, p.-54, and the Rev. E. S. Dixon, "Ornamental Poultry," 1848, 
 p. 8. For the turkey, Audubon, ibid, p. 4. For the capercailzie, 
 Llo 
 
 165. 
 
 yd, " Game Birds of Sweden," 1867, p. 23. 
 fMr. Hewitt, quoted in " Tegetmeier's Poultry Book " 1866.
 
 478 THE DESCENT OF MAN. 
 
 aversion to certain hens, which no care on the part of the 
 breeder can overcome. Mr. Hewitt informs me that some 
 hens are quite unattractive even to the males of their own 
 species, so that they may be kept with several cocks*during 
 a whole season, and not one egg out of forty or fifty will 
 prove fertile. On the other hand, with the long-tailed 
 duck (Harelda glacialis], " it has been remarked," says M. 
 Ekstrom, " that certain females are much more courted 
 than the rest. Frequently, indeed, one sees an individual 
 surrounded by six or eight amorous males." Whether 
 this statement is credible, I know not ; but the native 
 sportsmen shoot these females in order to stuff them as 
 decoys.* 
 
 With respect to female birds feeling a preference for 
 particular males we must bear in mind that we can judge 
 of choice being exerted only by analogy = If an inhabitant 
 of another planet were to behold a number of young 
 rustics at a fair courting a pretty girl and quarreling about 
 her, like birds at one of their places of assemblage, he 
 would, by the eagerness of the wooers to please her and to 
 display their finery, infer that she had thfc power of choice. 
 Now with birds the evidence stands thus; they have acute 
 powers of observation, and they seem to have some taste 
 for the beautiful both in color and sound. It is certain 
 that the females occasionally exhibit, from unknown 
 causes, the strongest antipathies and preferences for par- 
 ticular males. When the sexes differ in color or in other 
 ornaments the males with rare exceptions are the more 
 decorated, either permanently or temporarily during the 
 breeding-season. They sedulously display their various 
 ornaments, exert their voices, and perform strange antics in 
 the presence of the females. Even well-armed males, who, 
 it might be thought, would altogether depend for success 
 on the law of battle, are in most cases highly ornamented ; 
 and their ornaments have been acquired at the expense of 
 some loss of power. In other cases ornaments have been 
 acquired at the cost of increased risk from birds and beasts 
 of prey. With various species many individuals of both 
 sexes congregate at the same spot, and their courtship is a 
 prolonged affair. There is even reason to suspect that tb> 
 males and females within the same district do not always 
 succeed in pleasing each other and pairing. 
 
 *Quoted in Lloyd's "Game Birds of Sweden," p. 345.
 
 BIRDS, 479 
 
 What then are we to conclude from these facts and con- 
 siderations? Does the male parade his charms with so 
 much pomp and rivalry for no purpose? Are we not justi- 
 fied in believing that the female exerts a choice, and that 
 she receives the addresses of the male who pleases her most? 
 It is not probable that she consciously deliberates; but 
 she is most excited or attracted by the most beautiful, or 
 melodious, or gallant males. Nor need it be supposed that 
 the female studies each stripe or spot of color ; that the 
 peahen, for instance, admires each detail in the gorgeous 
 train of the peacock she is probably struck only by the 
 general effect. Nevertheless, after hearing how carefully 
 the male Argus pheasant displays his elegant primary wing- 
 feathers and erects his ocellated plumes in the right posi- 
 tion for their full effect; or again, how the male goldfinch 
 alternately displays his gold-bespangled wings, we ought 
 not to feel too sure that the female does not attend to each 
 detail of beauty. We can judge, as already remarked, of 
 choice being exerted, only from analogy; and the mental 
 powers of birds do not differ fundamentally from ours. 
 From these various considerations we may conclude that 
 the pairing of birds is not left to chance; but that those 
 males, which are best able by their various charms to please 
 or excite the female, are under ordinary circumstances 
 accepted. If this be admitted, there is not much difficulty 
 in understanding how male birds have gradually acquired 
 their ornamental characters. All animals present individ- 
 ual differences, and as man can modify his domesticated 
 birds by selecting the individuals which appear to him the 
 most beautiful, so the habitual or even occasional preference 
 by the female of the more attractive males would almost 
 certainly lead to their modification; and such modifications 
 might in the course of time be augmented to almost any 
 extent, compatible with the existence of the species. 
 
 Variability of Birds, and Especially of Their Secondary 
 Sexual Characters. Variability and inheritance are the 
 foundations for the work of selection. That domesticated 
 birds have varied greatly, their variations being inherited, 
 is certain. That birds in a state of nature have been modi- 
 fied into distinct races is now universally admitted. * Vari- 
 
 * According to Dr. Blasius ("Ibis," vol. ii, 1860, p. 297), there are 
 425 indubitable species of birds which breed in Europe, besides sixty
 
 480 THE DESCENT OF MAN, 
 
 ations may be divided into two classes; those which appea; 
 to our ignorance to arise spontaneously, and those which are 
 directly related to the surrounding conditions, so that all or 
 nearly, all the individuals of the same species are similarly 
 modified. Cases of the hitter kind have recently been observed 
 with care by Mr. J. A. Allen,* who shows that in the 
 United States many species of birds gradually become 
 more strongly colored in proceeding southward, and more 
 lightly colored in proceeding westward to the arid plains 
 of the interior. Both sexes seem generally to be affected 
 in a like manner, but sometimes one sex more than the 
 other. This result is not incompatible with the belief that 
 the colors of birds are mainly due to the accumulation of 
 successive variations through sexual selection ; for even 
 after the sexes have been greatly differentiated, climate 
 might produce an equal effect on both sexes, or a greater 
 effect on one sex than on the other, owing to some consti- 
 tutional difference. 
 
 Individual differences between the members of the same 
 species are admitted by every one to occur under a state of 
 nature. Sudden and strongly marked variations are rare ; 
 
 forms, which are frequently regarded as distinct species. Of the 
 latter, Blasius thinks that only ten are really doubtful and that the 
 other fifty ought to be united with their nearest allies; but this 
 shows that there must be a considerable amount of variation with 
 some of our European birds. It is also an unsettled point with 
 naturalists, whether several North American birds ought to be 
 ranked as specifically distinct from the corresponding European 
 species. So again many North American forms which until lately 
 were named as distinct species, are now considered to be local races. 
 
 *" Mammals and Birds of East Florida," also an "Ornithological 
 Reconnaissance of Kansas, etc." Noth withstanding the influence of 
 climate on the colors of birds, it is difficult to account for the dull or 
 dark tints of almost all the species inhabiting certain countries, for 
 instance, the Galapagos Islands under the equator, the wide, tem- 
 perate plains of Patagonia, and, as it appears, Egypt (see Mr. Harts- 
 horne in the "American Naturalist," 1873, p. 747). These countries 
 are open and afford little shelter to birds; but it seems doubtfuV 
 whether the absence of brightly colored species can be explained on 
 the principle of protection, for on the Pampas, which are equally 
 open, though covered by green grass, and where the birds would be 
 equally exposed to danger, many brilliant and conspicuously colored 
 species are common. I have sometimes speculated whether the pre- 
 vailing dull tints of the scenery in the above-named countries may 
 not have affected the appreciation of bright colors by the birds inhab- 
 iting them.
 
 BIRDS. 481 
 
 it is also doubtful whether if beneficial f ^ey would often be 
 preserved through selection and transmitted to succeeding 
 generations.* Nevertheless, it may be worth while to give 
 the few cases which I have been able to collect, relating 
 chiefly to color simple albinism and melanism being 
 excluded. Mr. Gould is well known to admit the exist- 
 ence of few varieties, for he esteems very slight differences 
 as specific; yet he statesf that near Bogota certain hum- 
 ming-birds belonging to the genus Cynanthus are divided 
 into two or three races or varieties, which differ from each 
 other in the coloring of the tail " some having the whole of 
 the feathers blue, while others have the eight central ones 
 tipped with beautiful green. " It does not appear that 
 intermediate gradations have been observed in this or the 
 following cases. In the males alone of one of the Austra- 
 lian paroquets " the thighs in some are scarlet, in others 
 grass-green." In another paroquet of the same country 
 "some individuals have the band across the wing-coverts 
 bright yellow, while in others the same part is tinged with 
 red."J In the United States some few of the males of the 
 Scarlet Tanager ( Tanagra rubra) have " a beautiful trans- 
 verse band of glowing red on the smaller wing-coverts;" 
 but this variation seems to be somewhat rare, so that its 
 preservation through sexual selection would follow only 
 under unusually favorable circumstances. In Bengal tho 
 honey buzzard (Pernis cristata) has either a small rudi- 
 
 * " Origin of Species." 5th edit., 1869, p. 104. I had always per- 
 ceived that rare and strongly marked deviations of structure, deserv- 
 ing to be called monstrosities, could seldom be preserved through 
 natural selection, and that the preservation of even highly beneficial 
 variations would depend to a certain extent on chance. I had also 
 fully appreciated the importance of mere individual differences, and 
 this led me to insist so strongly on the importance of that unconscious 
 form of selection by man which follows from the preservation of the 
 most valued individuals of each breed, without any intention on his 
 part to modify the characters of the breed. But until I read an able 
 Article in the " North British Review " (March, 1867, p. 289, ctseq.), 
 which has been of more use to me than any other review, I did not 
 see how great the chances were against the preservation of variations, 
 whether slight or strongly pronounced, occurring only in single 
 individuals. 
 
 f " Introduct. to the Trochilidae," p, 102. 
 
 j: Gould, " Hand-book to Birds of Australia," vol. ii, pp. 32, 68. 
 
 Audubon. "Ormtholog. Biography," 1838, vol. iv, p. 389.
 
 482 THE DESCENT OF MAN. 
 
 mental crest on its head, or none at all; so slight a differ- 
 ence, however, Would not have been worth notice, had not 
 this same species possessed in Southern India a well-marked 
 occipital crest formed of several graduated feathers."* 
 
 The following case is in some respects more interesting. 
 A pied variety of the raven, with the head, breast, abdomen, 
 and parts of the wings and tail-feathers white is con- 
 fined to the Feroe Islands. It is not very rare there, for 
 Graba saw during his visit from eight to ten living speci- 
 mens. Although the characters of this variety are not 
 quite constant, yet it has been named by several distin- 
 guished ornithologists as a distinct species. The fact of 
 the pied birds being pursued and persecuted with much 
 clamor by the other ravens of the island was the chief 
 cause which led Briiunich to conclude that they were 
 specifically distinct; but this is now known to be an error, f 
 This case seems analogous to that lately given of albino 
 birds not pairing from being rejected by their comrades. 
 
 In various parts of the northern seas a remarkable variety 
 of the common Guillemot ( Uria troile) is found; and in 
 Feroe one out of every five birds, according to Graba's esti- 
 mation, presents this variation. It is characterized;]; by a 
 pure white ring round the eye, with a curved narrow white 
 line an inch and a half in length extending back from the 
 ring. This conspicuous character lias caused the bird to 
 be ranked by several ornithologists as a distinct species 
 under the name of U. lacrymans, but it is now known to 
 be merely a variety. It often pairs with the common kind, 
 yet intermediate gradations have never been seen; nor is 
 this surprising, for variations which appear suddenly are 
 often, as I have elsewhere shown, transmitted either unal- 
 tered or not at all. We thus see that two distinct forms of 
 the same species may co-exist in the same district, and we 
 cannot doubt that if the one had possessed any advantage 
 
 *Jerdon, "Birds of India," vol. i, p. 108; and Mr. Blyth, in 
 " Land and Water," 1868, p. 381. 
 
 f Graba, "Tagebuch Reise nacb Faro," 1830, ss. 51-54. Macgilli- 
 vray, "Hist. British Birds," vol. iii, p. 745. "Ibis," vol. v, 1863, 
 p. 469. 
 
 f Graba, ibid, s. 54. Macgillivray, ibid, vol. v, p. 327. 
 
 " Variation of Animals and Plants under Domestication, "vol. ii, 
 p. 93.
 
 BIRDS. 483 
 
 owr the other it would soon have been multiplied to the 
 exclusion of the latter. If, for instance, the male pied 
 ravens, instead of being persecuted by their comrades, had 
 been highly attractive (like the above pied peacock) to the 
 black female ravens their numbers would have rapidly 
 increased. And this would have been a case of sexual 
 selection. 
 
 With respect to the slight individual differences which 
 are common, in a greater or less degree, to all the mem- 
 bers of the same species, we have every reason to believe 
 that they are by far the most important for the work of 
 selection. Secondary sexual characters are eminently 
 liable to vary, both with animals in a state of nature and 
 under domestication.* There is also reason to believe, as 
 we have seen in our eighth chapter, that variations are 
 more apt to occur in the male than in the female sex. All 
 these contingencies are highly favorable for sexual selec- 
 tion. Whether characters thus acquired are transmitted to 
 one sex or to both sexes depends, as we shall see in the 
 following chapter, on the form of inheritance which 
 prevails. 
 
 It is sometimes difficult to form an opinion whether cer- 
 tain slight differences between the sexes of birds are simply 
 the result of variability with sexually limited inheritance 
 without the aid of sexual selection or whether they have 
 been augmented through this latter process. I do not here 
 refer to the many instances where the male displays splen- 
 did colors or other ornaments of which the female partakes 
 to a slight degree; for these are almost certainly due to 
 characters primarily acquired by the male having been 
 more or less transferred to the female. But what are we to 
 conclude with respect to certain birds in which, for 
 instance, the eyes differ slightly in color in the two sexes ?f 
 In some cases the eyes differ conspicuously; thus with the 
 storks of the genus Xenorhynclms, those of the male are 
 blackish - hazel, while those of the female are gamboge- 
 yellow; with many hornbills (Buceros), as I hear from Mr. 
 Blyth.,1 the males have intense crimson eyes, and those of 
 
 *On these points see also " Variation of Animals and Plants under 
 Domestication," vol. i, p. 253; vol. ii, pp. 73, 75. 
 
 f See, for instance, on the irides of a Podica and Gallicrex in 
 "Ibis," vol. ii, 1860, p. 206; and vol. v, 1863, p. 426. 
 
 {See also Jerdon, " Birds of India," vol. i, pp. 243-245.
 
 484 THE DESCENT OF MAN. 
 
 the females are^ white. In the Buceros fiicornis, the hind 
 margin of the casque and a stripe on the crest of the beak 
 are black in the male, but not so in the female. Are we to 
 suppose that these black marks and the crimson color of 
 the eyes have been preserved or augmented through sexual 
 selection in the males? This is very doubtful; for Mr. 
 Bartlett showed me in the Zoological Gardens that the 
 inside of the mouth of this buceros is black in the male 
 and flesh-colored in the female; and their external appear- 
 ance or beauty would not be thus affected. I observed in 
 Chili * that the iris in the condor, when about a year old, 
 is dark-brown, but changes at maturity into a yellowish- 
 brown in the male, and into bright red in the female. The 
 male has also a small, longitudinal, leaden-colored, fleshy 
 crest or comb. The comb of many gallinaceous birds is 
 highly ornamental, and assumes vivid colors during the act 
 of courtship; but what are we to think of the dull-colored 
 comb of the condor which does not appear to us in the least 
 ornamental? The same question may be asked in regard to 
 various other characters, such as the knob on the base of 
 the beak of the Chinese goose (Anser cygnoidcs), which is 
 much larger in the male than in the female. No certain 
 answer can be given to these questions; but we ought to be 
 cautious in assuming that knobs and various fleshy appen- 
 dages cannot be attractive to the female, when we remem- 
 ber that with savage races of man various hideous 
 deformities deep scars on the face with the flesh raised 
 into protuberances, the septum of the nose pierced by sticks 
 or bones, holes in the ears and lips stretched widely open 
 are all admired as ornamental. 
 
 Whether or not unimportant differences between the 
 sexes, such as those just specified, have been preserved 
 through sexual selection, these differences, as well as all 
 others, must primarily depend on the laws of variation. On 
 the principle of correlated development, the plumage often 
 varies on different parts of the body, or over the whole 
 body, in the same manner. We see this well illustrated in 
 certain breeds of the fowl. In all the breeds the feathers 
 on the neck and loins of the males are elongated and are 
 called hackles; now when both sexes acquire a top-knot, 
 which is a new character in the genus, the feathers on the 
 
 " Zoology of the Voyage of H. M. S. ' Beagle, ' " 1841, p. 6.
 
 BIRDS. 485 
 
 head of the male become hackle-shaped, evidently on the 
 principle of correlation; while those on the head of the 
 female are of the ordinary shape. The color also of 
 the hackles forming the top-knot of the male is often cor- 
 related with that of the hackles on the neck and loins, as 
 may be seen by comparing these feathers in the golden and 
 silver - spangled Polish, the Houdans and Creve-creur 
 breeds. In some natural species we may observe exactly 
 the same correlation in the colors of these same feathers, 
 as in the males of the splendid gold and Amherst pheasants. 
 
 The structure of each individual feather generally causes 
 any change in its coloring to be symmetrical; we see this 
 in the various laced, spangled, and penciled breeds of the 
 fowl; and on the principle of correlation the feathers over 
 the whole body are often colored in the same manner. We 
 are thus enabled without much trouble to rear breeds with 
 their plumage marked almost as symmetrically as in natural 
 species. In laced and spangled fowls the colored margins 
 of the feathers are abruptly defined ; but in a mongrel 
 raised by me from a black Spanish cock glossed with green, 
 and a white game-hen, all the feathers were greenish-black, 
 excepting toward their extremities, which were yellowish- 
 white; but between the white extremities and the black 
 bases there was on each feather a symmetrical, curved zone 
 of dark-brown. In some instances the shaft of the feather 
 determines the distribution of the tints; thus with the 
 body-feathers of a mongrel from the same black Spanish 
 cock and a silver-spangled Polish hen, the shaft, together 
 with a narrow space on each side, was greenish-black, and 
 this was surrounded by a regular zone of dark-brown, edged 
 with brownish-white. In these cases we have feathers 
 symmetrically shaded, like those which give so much ele- 
 gance to the plumage of many natural species. I have 
 also noticed a variety of the common pigeon with the wing- 
 bars symmetrically zoned with three bright shades, instead 
 of being simply black on a slaty-blue ground, as in the 
 parent-species. 
 
 In many groups of birds the plumage is differently col- 
 ored in the several species, yet certain spots, marks, or 
 stripes are retained by all. Analogous cases occur with the 
 breeds of the pigeon, which usually retain the two wing- 
 bars, though they may be colored red, yellow, white, black, 
 or blue, the rest of the plumage being of some wholly dif-
 
 486 THE DESCENT OF MAN. 
 
 ferent tint. Here is a more curious case, in which certain 
 marks are retained, though colored in a manner almost 
 exactly the opposite of what is natural ; the aboriginal 
 pigeon has a blue tail, with the terminal halves of the outer 
 webs of the two outer tail-feathers white ; now there 
 is a sub - variety having a white instead of a blue tail, 
 with precisely that part black which is white in the parent- 
 species." * 
 
 Formation and Variability of tlie Ocelli or Eye- Like 
 Spots on the Plumage of Birds. As no ornaments are 
 more beautiful than the ocelli on the feathers of various 
 birds, on the hairy coats of some mammals, on the scales of 
 reptiles and fishes, on the skin of amphibians, on the wings 
 of many Lepidoptera and other insects, they deserve to be 
 especially noticed. An ocellus consists of a spot within a 
 ring of another color, like the pupil within the iris, but 
 the central spot is often surrouded by additional concentric 
 zones. The ocelli on the tail-coverts of the peacock offer 
 a familiar example, as well as those on the wings of the 
 peacock-butterfly (Vanessa). Mr. Trimen has given me a 
 description of a South African moth (Gynanisa isis), 
 allied to our emperor moth, in which a magnificent ocellus 
 occupies nearly the whole surface of each hinder wing ; it 
 consists of a black center, including a semi-transparent 
 crescent-shaped mark, surrounded by successive ocher- 
 yellow, black, ocher-yellow, pink, white, pink, brown and 
 whitish zones. Although we do not know the steps by 
 which these wonderfully beautiful and complex orna- 
 ments have been developed the process has probably been a 
 'simple one, at least with insects; for, as Mr. Trimen writes 
 to me, " no characters of mere marking or coloration are 
 so unstable in the Lepidoptera as the ocelli, both in number 
 and size." Mr. Wallace, who first called my attention to 
 this subject, showed me a series of specimens of our 
 common meadow-brown butterfly (Hipparchia janira) 
 exhibiting numerous gradations from a simple minute black 
 spot to an elegantly shaded ocellus. In a South African 
 butterfly (Gyllo leda, Linu.), belonging to the same family, 
 the ocelli are even still more variable. In some specimens 
 
 *Bechstein, " Naturgeschicbte Deutschlands," B. iv, 1795, s. 3J, 
 on a eub- variety of the Monck pigeon.
 
 BIRDS. 
 
 487 
 
 (a, fig. 53) large spaces on the upper surface of the wings 
 are colored black, and include irregular white marks; and 
 from this state a complete gradation can be traced into a 
 tolerably perfect ocellus (a 1 ), and this results from the 
 contraction of the irregular blotches of color. In another 
 series of specimens a gradation can be followed from 
 excessively minute white dots, surroundeJ by a scarcely 
 visible black line (b), into perfectly symmetrical and large 
 
 Pig. 53. Cyllo leda, Linn, from a drawing by Mr. Trimen, showing the extreme 
 range of variation in the ocelli. 
 
 a. Specimen, from Mauritius, upper 
 
 surface of fore wing. 
 a 1 . Specimen, from Natal, ditto. 
 
 6. Specimen, from Java, upper sur- 
 face of hind wing. 
 ft 1 . Specimen, from Mauritius, ditto. 
 
 ocelli (5 1 ).* In cases like these, the development of a 
 perfect ocellus does not require a long course of variation 
 and selection. 
 
 With birds and many other animals it seems to follow 
 from the comparison of allied species that circular spots 
 are often generated by the breaking up and contraction of 
 stripes. In the Tragopan pheasant faint white lines in the 
 
 * This wood-cut has been engraved from a beautiful drawing, most 
 kindly made for me by Mr. Trimen ; see also his description of the 
 wonderful amount of variation in the coloration and shape of the 
 wings of this butterfly, in his " Rhopalocera Africse Australia," p. 
 186.
 
 488 THE DESCENT OF MAN. 
 
 female represent the beautiful white spots in the male;* 
 and something of the same kind may be observed in the 
 two sexes of the Argus pheasant. However this may be, 
 appearances strongly favor the belief that, on the one hand, 
 a dark spot is often formed by the coloring matter being 
 drawn toward a central point from a surrounding zone, 
 which latter is thus rendered lighter; and, on the other 
 hand, that a white spot is often formed by the color being 
 driven away from a central point, so that it accumulates in 
 a surrounding darker zone. In either case an ocellus is the 
 result. The coloring matter seems to be a nearly constant 
 quantity, but is redistributed, either centripetally or cen- 
 trifugally. The feathers of the common guinea-fowl offer 
 a good instance of white spots surrounded by darker zones; 
 and wherever the white spots are large and stand near each 
 other the surrounding dark zones become confluent. In 
 the same wing-feather of the Argus pheasant dark spots 
 may be seen surrounded by a pale zone and white spots by 
 a dark zone. Thus the formation of an ocellus in its most 
 elementary state appears to be a simple affair. By what 
 further steps the more complex ocelli,, which are surrounded 
 by many successive zones of color, have been generated, I 
 will not pretend to say. But the zoned feathers of the 
 mongrels from differently colored fowls, and the extraor- 
 dinary variability of the ocelli on many Lepidoptera, lead 
 us to conclude that their formation is not a complex 
 process, but depends on some slight and graduated change 
 in the nature of the adjoining tissues. 
 
 Gradation of Secondary Sexual Characters, Cases of 
 gradation are important as showing us that highly complex 
 ornaments may be acquired by small successive steps. In 
 order to discover the actual steps by which the male of any 
 existing bird has acquired his magnificent colors or other 
 ornaments we ought to behold the long line of his extinct 
 progenitors; but this is obviously impossible. We may, 
 however, generally gain a clew by comparing all the species 
 of the same group if it be a large one; for some of them 
 will probably retain, at least partially, traces of their 
 former characters. Instead of entering on tedious details 
 respecting various groups, in which striking instances of 
 
 * Jerdon, " Birds of India," vol. iii, p. 517.
 
 BIRDS. 489 
 
 gradation could be given, it seems the best plan to take 
 one or two strongly marked cases, for instance that of the 
 peacock, in order to see if light can be thrown on the steps 
 by which this bird has become so splendidly decorated. 
 The peacock is chiefly remarkable from the extraordinary 
 length of his tail-coverts; the tail itself not being much 
 elongated. The barbs along nearly the whole length of 
 these feathers stand separate or are decomposed; but this 
 is the case with the feathers of many species and with some 
 varieties of the domestic fowl and pigeon. The barbs 
 coalesce toward the extremity of the shaft forming the 
 oval disk or ocellus, which is certainly one of the most 
 beautiful objects in the world. It consists of an iridescent, 
 intensely blue, indented center, surrounded by a rich green 
 zone, this by a broad coppery-brown zone, and this by five 
 other narrow zones of slightly different iridescent shades. 
 A trifling character in the disk deserves notice; the barbs 
 for a space along one of the concentric zones are more or 
 less destitute of their barbules, so that a part of the disk is 
 surrounded by an almost transparent zone, which gives it a 
 highly finished aspect. But I have elsewhere described* 
 an exactly analogous variation in the hackles of a sub- 
 variety of the gamecock in which the tips, having a metallic 
 luster, " are separated from the lower part of the feather 
 by a symmetrically shaped transparent zone composed of 
 the naked portions of the barbs." The lower margin or 
 base of the dark blue center of the ocellus is deeply 
 indented on the line of the shaft. The surrounding zones 
 likewise show traces, as may be seen in the drawing (fig. 
 54), of indentations, or rather breaks. These indentations 
 are common to the Indian and Javan peacocks (Pavo 
 cristatus and P. muticus) ; and they seem to deserve 
 particular attention as probably connected with the devel- 
 opment of the ocellus; but for a long time I could not 
 conjecture their meaning. 
 
 If we admit the principle of gradual evolution there 
 must formerly have existed many species which presented 
 every successive step between the wonderfully elongated 
 tail-coverts of the peacock and the short tail-coverts of all 
 ordinary birds; and again between the magnificent ocelli 
 
 * "Variation of Animals and Plants under Domesticatiop," vol. i. 
 p. 254.
 
 490 
 
 THE DESCENT OF MAN. 
 
 of the former and the simpler ocelli or mere colored spots 
 on other birds; and so with all the other characters of the 
 peacock. Let us look to the allied Gallinaceas for any still- 
 existing gradations. The species and sub-species of Poly- 
 plectrbn inhabit countries adjacent to the native land of the 
 peacock; and they so far resemble this bird that they are 
 sometimes called peacock-pheasants. I am also informed 
 
 Fig. 54. Feather of peacock, about two-thirds of natural size, drawn by Mr. 
 Ford. The transparent zone is represented by the outermost white zone, 
 confined to the upper end of the disk. 
 
 by Mr. Bartlett that they resemble the peacock in their 
 voice and in some of their habits. During the spring the 
 males, as previously described, strut about before the com- 
 paratively plain-colored females, expanding and erecting 
 their tail and wing feathers, which are ornamented with 
 numerous ocelli. I request the reader to turn back to the 
 drawing (fig. 51) of a Polyplectron. In P. napolconis 
 the ocelli are confined to the tail, and the back is of a rich
 
 BIRDS. 491 
 
 metallic blue; in which respects this species approaches the 
 Java peacock. P. hardwicMi possesses a peculiar top-knot, 
 which is also somewhat like that of the Java peacock. In 
 all the species the ocelli on the wings and tail are either 
 circular or oval, and consist of a beautiful, iridescent, 
 greenish-blue or greenish-purple disk with a black border. 
 This border in P. chinquis shades into brown, edged with 
 cream color, so that the ocellus is here surrounded with 
 variously shaded, though not bright, concentric zones. 
 The unusual length of the tail-coverts is another remark- 
 able character in Polyplectron; for in some of the species 
 they are half and in others two-thirds as long as the true 
 tail feathers. The tail-coverts are ocellated as in the 
 peacock. Thus the several species of Polyplectron mani- 
 festly make a graduated approach to the peacock in the 
 length of their tail-coverts, in the zoning of the ocelli, and 
 in some other characters. 
 
 Notwithstanding this approach, the first species of Poly- 
 plectron which I examined almost made me give up the 
 search; for I found not only that the true tail-feathers which 
 in the peacock are quite plain, were ornamented with ocelli, 
 but that the ocelli on all the feathers differed fundament- 
 ally from those of the peacock, in there being two on the 
 same feather (fig. 55), one on each side of the shaft. 
 Hence I concluded that the early progenitors of the pea- 
 cock could not have resembled a Polyplectron. But on 
 continuing my search I observed that in some of the spe- 
 cies the two ocelli stood very near each other; that in the 
 tail-feathers of P. hardiuickii they touched each other ; 
 and finally that on the tail-coverts of this same species as 
 well as of P. malaccense (fig. 56) they were actually con- 
 |fluent. As the central part alone is confluent, an indenta- 
 ' tion is left at both the upper and lower ends; and the sur- 
 rounding colored zones are likewise indented. A single 
 ocellus is thus formed on each tail-covert, though still 
 plainly betraying its double origin. These confluent ocelli 
 differ from the single ocelli of the peacock in having an 
 indentation at both ends instead of only at the lower or 
 basal end. The explanation, however, of this difference is 
 not difficult; in some species of Polyplectron the two oval 
 ocelli on the same feather stand parallel to each other; in 
 other species (as in P. chinquis) they converge toward one 
 end; now the partial confluence of two convergent ocelli
 
 492 THE DESCENT OF MAN. 
 
 would manifestly leave a much deeper indentation at the 
 divergent than at the convergent end. It is also manifest 
 that if the convergence were strongly pronounced and the 
 confluence complete, the indentation at the convergent end 
 would tend to disappear. 
 
 The tail-feathers in both species of the peacock are en- 
 tirely destitute of ocelli, and this apparently is related to 
 their being covered up and concealed by the long tail- 
 coverts. In this respect they differ remarkably from the 
 
 Fig. 55. Part of a tail-covert of Poly- Fig. 56. Part of a tale-covert of Poly- 
 plectron chinquis, with the two plectrou malaocense, with the two 
 ocelli of natural size. ocelli, partially confluent, of nat- 
 
 ural size. 
 
 tail-feathers of Polyplectron, which in most of the species 
 are ornamented with larger ocelli than those on the tail- 
 coverts. Hence I was led carefully to examine the tail- 
 feathers of the several species, in order to discover whether 
 their ocelli showed any tendency to disappear; and to my 
 great satisfaction this appeared to be so. The central tail- 
 feathers of P. napoleonis have the two ocelli on each side 
 of the shaft perfectly developed; but the inner ocellus be- 
 comes less and less conspicuous on the more exterior tail- 
 feathers, until a mere shadow or rudiment is left on the 
 inner side of the outermost feather. Again, in P. malac-
 
 BIRDS. 493 
 
 cense, the ocelli on the tail-coverts are, as we have seen, 
 confluent; and these feathers are of unusual length, being 
 two-thirds of the length of the tail-feathers, so that in both 
 these respects they approach the tail-coverts of the peacock. 
 Now in P. malaccense the two central tail-feathers alone 
 are ornamented, each with two brightly colored ocelli, the 
 inner occellus having completely disappeared from all the 
 other tail-feathers. Consequently the tail-coverts and tail- 
 feathers of this species of Polyplectron make a near approach 
 in structure and ornamentation to the corresponding feathers 
 of the peacock. 
 
 As far, then, as gradation throws light on the steps by 
 which the magnificent train of the peacock has been 
 acquired, hardly anything more is needed. If we picture 
 to ourselves a progenitor of the peacock in an almost 
 exactly intermediate condition between the existing peacock 
 with his enormously elongated tail-coverts ornamented with 
 single ocelli, and an ordinary gallinaceous bird with short 
 tail-coverts merely spotted with some color, we shall see a 
 bird allied to Polyplectron that is, with tail-coverts capable 
 of erection and expansion, ornamented with two partially 
 confluent ocelli, and long enough almost to conceal the 
 tail-feathers, the latter having already partially lost their 
 ocelli. The indentation of the central disk and of the 
 surrounding zones of the ocellus in both species of peacock 
 speaks plainly in favor of this view and is otherwise inexpli- 
 cable. The males of the Polyplectron are no doubt beautiful 
 birds, but their beauty, when viewed from a little distance, 
 cannot be compared with that of the peacock. Many female 
 progenitors of the peacock must, during a long line of 
 descent, have appreciated this superiority; for they have 
 unconsciously, by the continued preference of the most 
 beautiful males, rendered the peacock the most splendid 
 of living birds. 
 
 Argus Pheasant. Another excellent case for investiga- 
 tion is offered by the ocelli on the wing-feathers of the 
 - Argus pheasant, which are shaded in so wonderful a 
 manner as to resemble balls lying loose within sockets and 
 consequently differ from ordinary ocelli. No oi?e, I pre- 
 sume, will attribute the shading, which has excited the 
 admiration of many experienced artists, to chance to the 
 fortuitous concourse of atoms of coloring matter;- That
 
 494 
 
 THE DESCENT OF MAN. 
 
 these ornaments should have been formed through the selec- 
 tion of many successive variations, not one of which was 
 originally intended to produce the ball-and-socket effect, 
 seems as incredible as that one of Kapheal's Madonnas 
 should have been formed by the selection of chance daubs 
 
 of paint made by a long 
 ABC succession of young art- 
 ists, not one of whom 
 intended at first to draw 
 the human figure. In 
 order to discover how 
 the ocelli have been 
 developed we cannot 
 look to a long line of 
 progenitors nor to many 
 closely allied forms, for 
 such do not now exist. 
 But fortunately the 
 several feathers on the 
 wing suffice to give us 
 a clew to the problem, 
 and they prove to dem- 
 onstration that a gra- 
 dation is at least pos- 
 sible from a mere spot 
 to a finished ball-and- 
 socket ocellus. 
 
 The wing - feathers, 
 bearing the ocelli, are 
 covered with dark 
 stripes (fig. 57) or 
 with rows of dark spots 
 (fig. 59), each stripe or 
 
 Part of secondary wing-feather of ,. nw f c-n^tc vnnniiirr 
 _; pheasant, showing two perfect ocelli, row ol 6 P ots H'nillllg 
 a and b. A, B, C, D, etc., are dark stripes 
 running obliquely down, each to an ocellus. 
 
 [Much of the web on both sides, especially 
 to the left of the shaft, has been cut off.] 
 
 obliquely down the 
 outer side of 
 
 the shaft 
 
 to one of the ocelli. 
 The spots are gen- 
 erally elongated in a line transverse to the row in which 
 they stand. They often become confluent either in the line 
 of the row and then they form a longitudinal stripe or 
 transversely, that is, with the spots in the adjoining rows, 
 and then they, form transverse stripes. A spot sometimes
 
 BIRDS. 
 
 495 
 
 breaks up into smaller spots,, which still stand in their proper 
 places. 
 
 It will be convenient first to describe a perfect ball-and- 
 socket ocellus. This consists of an intensely black circular 
 ring, surrounding a space shaded so as exactly to resemble 
 a ball. The figure here given has been admirably drawn 
 by Mr. Ford and well en- 
 graved, but a wood-cut 
 cannot exhibit the exqui- 
 site shading of the original. 
 The ring is almost alwa} r s 
 slightly broken or inter- 
 rupted (see fig. 57) at a 
 point in the upper half a 
 little to the right of and 
 above the white shade on 
 the inclosed ball; it is also 
 sometimes broken toward 
 thebase on the right hand. 
 These little breaks have an 
 important meaning. The 
 ring is always much thick- 
 ened, with the edges ill- 
 defined toward the left- 
 hand upper corner, the 
 feather being held erect in 
 the position in which it is 
 here drawn. Beneath this 
 thickened part there is on 
 the surface of the ball an ob- 
 lique, almost pure white mark which shades off downward 
 into a pale-leaden hue, and this into yellowish and brown 
 tints, which insensibly become darker and darker toward the 
 lower part of the ball. It is this shading which gives so 
 admirably the effect of light shining on a convex surface. 
 If one of the balls be examined it will be seen that the 
 lower part is of a brown tint and is indistinctly separated 
 -by a curved oblique line from the upper part, which is yel- 
 lower and more leaden; this curved oblique line runs at 
 right angles to the longer axis of the white patch of light, 
 and indeed of all the shading; but this difference in color, 
 which cannot of course be shown in the wood-cut, does not 
 in the least interfere with the perfect shading of the ball. 
 
 . 58. Basal part of the secondary 
 wing-feather nearest to the body.
 
 496 THE DESCENT OF MAN. 
 
 It should be particularly observed that each ocellus stands 
 in obvious connection either with a dark stripe or with a 
 longitudinal row of dark spots, for both occur indifferently 
 on the same feather. Thus in fig. 57 stripe A runs to 
 ocellus a; B runs to ocellus b; stripe C is broken in the 
 upper part and runs down to the next succeeding ocellus, 
 not represented in the wood-cut; D to the next lower one, 
 and so with the stripes E and F. Lastly the several ocelli 
 are separated from each other by a pale surface bearing 
 irregular black marks. 
 
 I will next describe the other extreme of the series, 
 namely, the first trace of an ocellus. The short secondary 
 wing-feather (fig. 58), nearest to the body, is marked like 
 the other feathers, with oblique, longitudinal, rather irreg- 
 ular rows of very dark spots. The basal spot, or that near- 
 est the shaft in the five lower rows (excluding the lowest 
 one), is a little larger than the other spots of the same row, 
 and a little more elongated in a transverse direction. It 
 differs also from the other spots by being bordered on its 
 upper side with some dull fulvous shading. But this spot 
 is not in any way more remarkable than those on the plum- 
 age of many birds, and might easily be overlooked. The 
 next higher spot does not differ at all from the upper ones 
 in the same row. The larger basal spots occupy exactly 
 the same relative position on these feathers as do the per- 
 fect ocelli on the longer wing-feathers. 
 
 By looking to the next two or three succeeding wing- 
 feathers, an absolutely insensible gradation can be traced 
 from one of the last described basal spots, together with the 
 next higher one in the same row, to a curious ornament, 
 which cannot be called an ocellus, and which I will name, 
 from the want of a better term, an "elliptic ornament." 
 These are shown in the accompanying figure (fig. 59). AVo 
 here see several oblique rows, A, B, C, D, etc. (see the let- 
 tered diagram on the right hand), of dark spots of the 
 usual character. Each row of spots runs down to and i 
 connected with one of the elliptic ornaments, in exactly 
 the same manner as each stripe in fig. 57 runs down to, 
 and is connected with, one of the ball-and-socket o'celli. 
 Looking to any one row, for instance, B, in fig. 59, the 
 lowest mark (b) is thicker and considerably longer than tho 
 upper spots, and has its left extremity pointed and curve. I 
 upward. This black mark is abruptly bordered on its
 
 BIRDS. 
 
 49? 
 
 upper side by a rather broad space of richly shaded tints, 
 beginning with a narrow brown zone, which passes into 
 orange, and this into a pale leaden tint, with the end toward 
 the shaft much paler. These shaded tints together fill up 
 the whole inner space of the elliptic ornament. The mark 
 
 Pig. 59. Portion of one of the secondary wing-feathers near the body, showing 
 the so-called elliptic ornaments. The right-hand figure is given merely as 
 a diagram for the sake of the letters of reference. 
 
 A, B, C, D, etc. Rows of spots running down to and forming the elliptic 
 ornaments. 
 
 b. Lowest spot or mark in row B. 
 
 c. The next succeeding spot or mark in the same row. 
 
 d. Apparently a broken prolongation of the spot C in the same row B. 
 
 (b) corresponds in every respect with the basal shaded spot 
 of the simple feather described in the last paragraph (fig. 
 58), but is more highly developed and more brightly col- 
 ored. Above and to the right of this spot (b fig. 59), with 
 i-ts bright shading, there is a long, narrow, black mark (c), 
 belonging to the same row, and which is arched a little 
 downward so as to face (b). This mark is sometimes broken 
 into two portions. It is also narrowly edged on the lower 
 side with a fulvous tint. To the left of and above (c), in 
 the same oblique direction, but always more or less distinct
 
 498 THE DESCENT OF MAN. 
 
 from it, there is another black mark (d). This mark is 
 generally sub-triangular and irregular in shape, but in the 
 one lettered in the diagram it is unusually narrow, elon- 
 gated and regular. It apparently consists of a lateral and 
 broken prolongation of the mark (c), together with its con- 
 fluence with a broken and prolonged part of the next spot 
 above; but I do not feel sure of this. These three marks, 
 (b), (c) and (d), Avith the intervening bright shades, form 
 together the so-called elliptic ornament. These ornaments 
 placed parallel to the shaft, manifestly correspond in posi- 
 tion with the ball-and-socket ocelli. Their extremely ele- 
 gant appearance cannot be appreciated in the drawing, as 
 the orange and leaden tints, contrasting so well with the 
 black marks, cannot be shown. 
 
 Between one of the elliptic ornaments and a perfect 
 ball-and-socket ocellus the gradation is so perfect that it is 
 scarcely possible to decide when the latter term ought to be 
 used. The passage from the one into the other is effected 
 by the elongation and greater curvature in the opposite 
 directions of the lower black mark (b fig. 59), and more 
 especially of the upper one (c), together with the contrac- 
 tion of the elongated sub-triangular or narrow mark ^d), so 
 that at last these three marks become confluent, forming an 
 irregular elliptic ring. This ring is gradually rendered 
 more and more circular and regular, increasing at the same 
 time in diameter. I have here given a drawing (fig. 60) of 
 the natural size of an ocellus not as yet quite perfect. 
 The lower part of the black ring is much more curved than is 
 the lower mark in the elliptic ornament (b fig. 59). The 
 upper part of the ring consists of two or three separate 
 portions; and there is only a trace of the thickening of the 
 portion which forms the black mark above the white shade. 
 This white shade itself is not as yet much concentrated; 
 and beneath it the surface is brighter colored than in a per- 
 fect ball-and-socket ocellus. Even in the most perfect 
 ocelli traces of the junction of three or four elongated 
 black marks, by which the ring has been formed, may often 
 be detected. The irregular sub-triangular or narrow mark 
 (d fig. 59), manifestly forms, by its contraction and equal- 
 ization, the thickened portion of the ring above the white 
 shade on a perfect ball-and-socket ocellus. The lower part 
 of the ring is invariably a little thicker than the other 
 parts (see fig. 57), and this follows from the lower black
 
 BIRDS. 
 
 499 
 
 mark of the elliptic ornament (3 fig. 59) having originally 
 "been thicker than the upper mark (c). Every step can be 
 followed in the process of confluence and modification; and 
 the black ring which sur- 
 rounds the ball of the ocellus 
 is unquestionably formed by 
 the union and modification 
 of the three black marks, b, c, 
 d, of the elliptic ornament. 
 The irregular zigzag black 
 marks between the successive 
 
 '. GO. 
 
 Kig. 61. 
 
 Fig. 60. An ocellus in an intermedate condition between the elliptic ornament 
 and the perfect ball-and-socket ocellus. 
 
 Fig. 61. Portion near summit of one of the secondary wing-feathers, bearing 
 perfect ball-and-socket ocelli, a. Ornamented upper part. b. Uppermost, 
 imperfect ball-and-socket ocellus. (The shading above the white mark on 
 the summit of the ocellus is here a little too dark.) c. Perfect ocellus. 
 
 ocelli (see again fig. 57) are plainly due to the breaking up 
 ot the somewhat more regular but similar marks between 
 the elliptic ornaments. 
 
 The successive steps in the shading of the ball-and- 
 socket ocelli can be followed out with equal clearness. 
 The brown, orange and pale-leadened narrow zones which 
 border the lower black mark of the elliptic ornament can
 
 iN30 THE DESCENT OF MAN. 
 
 be seen gradually to become more and more softened and 
 shaded into each other, with the upper lighter part toward 
 the left-hand corner rendered still lighter, so as to become 
 almost white and at the same time more contracted. But 
 even in the most perfect ball-and-socket ocelli a slight dif- 
 fereace in the tints, though not in the shading, between 
 the upper and lo\*er parts of the ball can be perceived, as 
 before noticed; and the line of separation is oblique in the 
 same direction as the bright-colored shades of the elliptic 
 flrnamects. Thus almost every minute detail in the shape 
 and coloring of the ball-and-socket ocelli can be shown to 
 follow f/om gradual changes in the elliptic ornaments; and 
 the development of the latter can be traced by equally 
 6m all steps from the union of two almost simple spots, the 
 lower one (fig. 58) having some dull fulvous shading on its 
 upper side. 
 
 The extremities of the longer secondary feathers which 
 bear the perfect ball-and-socket ocelli are peculiarly orna- 
 mented (fig. 61). The oblique longitudinal stripes sud- 
 denly cease upward and become confused; and above this 
 limit the whole upper end of the feather (a) is covered 
 with white dots surrounded by little black rings standing 
 on a dark ground. The oblique stripe belonging to the 
 uppermost ocellus (b) is barely represented by a very short 
 irregular black mark with the usual curved, transverse 
 base. As this stripe is thus abruptly cut off we can per- 
 haps understand from what has gone before how it is that 
 the upper thickened part of the ring is here absent; for, as 
 before stated, this thickened part apparently stands in 
 some relation with a broken prolongation from the next 
 higher spot. From the absence of the upper and thickened 
 part of the ring the uppermost ocellus, though perfect in 
 all other respects, appears as if its top had been obliquely 
 sliced off. It would, I think, perplex any one who believes 
 that the plumage of the Argus pheasant was created as we 
 now see it to account for the imperfect condition of the 
 uppermost ocellus. I should add that on the secondary 
 wing-feather farthest from the body all the ocelli are 
 smaller and less perfect than on the other feathers and 
 have the upper part of the ring deficient, as in the case 
 just mentioned. The imperfection here seems to be con- 
 nected with the fact that the spots on this feather show 
 less tendency than usual to become confluent into stripes;
 
 BIRDS. 501 
 
 they are, on the contrary, often broken up into smaller 
 spots, so that two or three rows run down to the same 
 ocellus. 
 
 There still remains another very curious point, first 
 observed by Mr. T. W. Wood,* which deserves attention. 
 In a photograph, given me by Mr. Ward, of a specimen 
 mounted as in the act of display, it may be seen that on the 
 feathers which are held perpendicularly, the white marks 
 on the ocelli, representing light reflected from a convex 
 surface, are at the upper or farther end, that is, are directed 
 upward; and the bird while displaying himself on the 
 ground would naturally be illuminated from above. But 
 here comes the curious point, the outer feathers are held 
 almost horizontally, and their ocelli ought likewise to 
 appear as if illuminated from above, and consequently the 
 white marks ought to be placed on the upper sides of the 
 ocelli; and, wonderful as is the fact, they are thus placed! 
 Hence the ocelli on the several feathers, though occupying 
 very different positions with respect to the light, all appear 
 as if illuminated from above, just as an artist would have 
 shaded them. Nevertheless they are not illuminated from 
 strictly the same point as they ought to be; for the white 
 marks on the ocelli of the feathers, which are held almost 
 horizontally, are placed rather too much toward the farther 
 end; that is, they are not sufficiently lateral. We have, 
 however, no right to expect absolute perfection in a part 
 rendered ornamental through sexual selection, any more 
 than we have in a part modified through natural selection 
 for real use; for instance, in that wondrous organ the 
 human eye. And we know what Helmholtz, the highest 
 authority in Europe on the subject, has said about the 
 human eye, that if an optician had sold him an instrument 
 BO carelessly made, he would have thought himself fully 
 justified in returning it. f 
 
 We have now seen that a perfect series can be followed, 
 from simple spots to the wonderful ball-and-socket orna- 
 ments. Mr. Gould, who kindly gave me some of these 
 feather*, fully agrees with me in the completeness of the 
 gradation. It is obvious that the stages in development 
 
 * The " Field," May 28, 1870. 
 
 f " Popular Lectures on Scientific Subjects," Eng. trans., 1873, pp. 
 219. 227, 269, 890.
 
 502 THE DESCENT OF MAN. 
 
 exhibited by the feathers on the same bird do not at all 
 necessarily show us the steps passed through by the extinct 
 progenitors of the species; but they probably give us the 
 clue to the actual steps, and they at least prove to demon- 
 stration that a gradation is possible. Bearing in mind how 
 carefully the male Argus pheasant displays his plumes 
 before the female, as well as the many facts rendering it 
 probable that female birds prefer the more attractive males, 
 no one who admits the agency of sexual selection in any 
 case will deny that a simple dark spot with some fulvous 
 shading might be converted, through the approximation 
 and modification of two adjoining spots, together with 
 some slight increase of color, into one of the so-called ellip- 
 tic ornaments. These latter ornaments have been shown 
 to many persons, and all have admitted that they are beau- 
 tiful, some thinking them even more so than the ball-and- 
 socket ocelli. As the secondary plumes became lengthened 
 through sexual selection, and as the elliptic ornaments 
 increased in diameter, their colors apparently became less 
 bright; and then the ornamentation of the plumes had to 
 be gained by an improvement in the pattern and shading ; 
 and this process was carried on until the wonderful ball- 
 and-socket ocelli were finally developed. Thus we can 
 understand and in no other way as it seen.? to me the 
 present condition and origin of the ornaments on the 
 wing-feathers of the Argus pheasant. 
 
 From the light afforded by the principle of gradation 
 from what we know of the laws of variation from the 
 changes which have taken place in many of our domesti- 
 cated birds and, lastly, from the character (as we shall 
 hereafter see more clearly) of the immature plumage of 
 young birds we can sometimes indicate, with a certain 
 amount of confidence, the probable steps by which the 
 males have acquired their brilliant plumage and various 
 ornaments; yet in many cases we are involved in complete 
 darkness. Mr. Gould several years ago pointed out to me 
 a humming-bird, the Urosticte benjaniini, remarkable for 
 the curious differences between the sexes. The male, 
 besides a splendid gorget, has greenish-black tail-feathers 
 with the four central ones tipped with white; in the female, 
 as with most of the allied species, the three outer tail- 
 feathers on each side are tipped with white, so that the
 
 BIRDS. 503 
 
 male has the four central, while the female has the six exte- 
 rior feathers ornamented with white tips. What makes the 
 case more curious is that, although the coloring of the tail 
 differs remarkably in both sexes of many kinds of hum- 
 ming-birds, Mr. Gould does not know a single species, 
 besides the Urosticte, in which the male has the four central 
 feathers tipped with white. 
 
 The Duke of Argyll, in commenting on this case,* 
 passes over sexual selection, and asks: " What explanation 
 does the law of natural selection give of such specific 
 varieties as these ?" He answers " none whatever;" and I 
 quite agree with him. But can this be so confidently 
 said of sexual selection ? Seeing in how many ways the 
 tail-feathers of humming-birds differ, why should not 
 the four central feathers have varied in this one species alone, 
 so as to have acquired white tips ? The variations may 
 have been gradual or somewhat abrupt, as in the case 
 recently given of the humming-birds near Bogota, in which 
 certain individuals alone have the " central tail-feathers 
 tipped with beautiful green." In the female of the Urosticte 
 I noticed extremely minute or rudimental white tips to the 
 two outer of the four central black tail-feathers; so that 
 here we have an indication of change of some kind in the 
 plumage of this species. If we grant the possibility of the 
 central tail feathers of the male varying in whiteness, there 
 is nothing strange in such variations having been sexually 
 selected. The Avhite tips, together with the small white 
 ear-tuffs, certainly add, as the Duke of Argyll admits, to 
 the beauty of the male ; and whiteness is apparently appre- 
 cited by other, birds, as may be inferred from such cases as 
 the snow-white male of the bell-bird. The statement made 
 by Sir R. Heron should not be forgetten, namely, that his 
 peahens, when debarred from access to the pied peacock, 
 would not unite with any other male, and during that season 
 produced no offspring. Nor is it strange that variations in 
 the tail-feathers of the Urosticte should have been specially 
 selected for the sake of ornament, for the next succeeding 
 genus fn the family takes its name of Metallura from the 
 splendor of these feathers. We have, moreover, good 
 evidence that humming-birds take especial pains in dis- 
 
 *" The Reign of Law," 1867, p. 247.
 
 504 THE DESCENT OF MAN. 
 
 w their tail-feathers; Mr. Belt,* after describing the 
 iuty^of the Florisuga mellivora, says: " I have seen the 
 female sitting on a branch and two males displaying their 
 charms in front of her. One would shoot up like a rocket, 
 then, suddenly expanding the snow-white tail, like an 
 inverted parachute, slowly descend in front of her, turning 
 round gradually to show off back and front. . . . The 
 expanded white tail covered more space than all the rest of 
 the bird, and was evidently the grand feature in the per- 
 formance. While one male was descending the other 
 would shoot up and come slowly down expanded. The 
 entertainment would end in a fight between the two per- 
 formers; but whether the most beautiful or the most pugna- 
 cious was the accepted suitor, I know not." Mr. Gould, 
 after describing the peculiar plumage of the Urosticte, 
 adds, "that ornament and variety is the sole object, I have 
 myself but little doubt."f If this be admitted, we can per- 
 ceive that the males which during former times were 
 decked in the most elegant and novel manner would have 
 gained an advantage, not in the ordinary struggle for life, 
 but in rivalry with other males, and would have left a 
 larger number of offspring to inherit their newly acquired 
 beauty. 
 
 *The Naturalist in Nicaragua," 1874, p. 112. 
 f " Introduction to the Trochilidse," 1861, p, 110.
 
 BIRDS. 505 
 
 CHAPTER XV. 
 
 BIEDS continued. 
 
 Discussion as to why the males alone of some species, and both sexes 
 of others, are brightly colored On sexually limited inheritance, 
 as applied to various structures and to brightly colored plumage 
 Nidification in relation to color Loss of nuptial plumage dur- 
 ing the winter. 
 
 WE have in this chapter to consider why the females of 
 many birds have not acquired the same ornaments as the 
 male; and why, on the other hand,, both sexes of many 
 other birds are equally, or almost equally, ornamented? In 
 the following chapter we shall consider the few cases 
 in which the female is more conspicuously colored than the 
 male. 
 
 In my " Origin of Species"* I briefly suggested that 
 the long tail of the peacock would be inconvenient and the 
 conspicuous black color of the male capercailzie dangerous 
 to the female during the period of incubation; and conse- 
 quently that the transmission of these characters from the 
 male to the female offspring had been checked through 
 natural selection. I still think that this may have occurred 
 in some few instances; but after mature reflection on all 
 the facts which I have been able to collect, I am now 
 inclined to believe that when the sexes differ the successive 
 variations have generally been from the first limited in 
 their transmission to the same sex in which they first 
 arose. Since my remarks appeared the subject of sexual 
 coloration has been discussed in some very interesting 
 papers by Mr. Wallace,! who believes that in almost all 
 Cases the successive variations tended at first to be trans- 
 mitted equally to both sexes; but that the female Avas saved, 
 
 * Fourth edition, 1866, p. 241. 
 
 I- " Westminster Review." July, 1867. "Journal of Travel." vol. 
 i, 1868, p. 73.
 
 506 THE DESCENT OF MAN. 
 
 through natural selection, from acquiring the conspicuous 
 colors of the male, owing to the danger which she would 
 thus have incurred during incubation. 
 
 This view necessitates a tedious discussion on a difficult 
 point, namely, whether the transmission of a character 
 which is at first inherited by both sexes can be subsequently 
 limited in its transmission to one sex alone by means of 
 natural selection. We must bear in mind, as shown in the 
 preliminary chapter on sexual selection, that characters 
 which are limited in their development to one sex are 
 always latent in the other. An imaginary illustration will 
 best aid us in seeing the difficulty of the case; we may sup- 
 pose that a fancier wished to make a breed of pigeons, in 
 which the males alone should be colored of a pale blue, 
 while the females retained their former slaty tint. As with 
 pigeons characters of all kinds are usually transmitted to 
 both sexes equally, the fancier would have to try to convert 
 this latter form of inheritance into sexually limited trans- 
 mission. All that he could do would be to persevere in 
 selecting every male pigeon which was in the least degree 
 of a paler blue; and the natural result of this process, if 
 steadily carried on for a long time, and if the pale varia- 
 tions were strongly inherited or often recurred, would be 
 to make his whole stock of a lighter blue. But our fancier 
 would be compelled to match, generation after generation, 
 his pale-blue males with slaty females, for he wishes to keep 
 the latter of this color. The result would generally be the 
 production either of a mongrel piebald lot, or more prob- 
 ably the speedy and complete loss of the pale-blue tint; for 
 the primordial slaty color would be transmitted with pre- 
 potent force. Supposing, however, that some pale-blue 
 males and slaty females were produced during each succes- 
 sive generation, and were always crossed together, then the 
 slaty females would have, if I may use the expression, much 
 blue blood in their veins, for their fathers, grandfathers, 
 etc., will all have been blue birds. Under these circum- 
 stances it is conceivable (though I know of no distinct facts 
 rendering it probable) that the slaty females might acquire 
 so strong a latent tendency to pale-blueness that they would 
 not destroy this color in their male offspring, their female 
 offspring still inheriting the slaty tint. If so, the desired 
 end of making a breed with the two sexes permanently dif- 
 ferent in color might be gained.
 
 BIRDS. 507 
 
 The extreme importance, or rather necessity, in the 
 above case of the desired character, namely, pale-blueness, 
 oeing present though in a latent state in the female, so that 
 the male offspring should not be deteriorated, will be best 
 appreciated as follows: the male of Sremmerring's pheasant 
 has a tail thirty-seven inches in length, while that of the 
 female is only eight inches; the tail of the male common 
 pheasant is about twenty inches, and that of the female 
 twelve inches long. Now if the female Scemmerring pheas- 
 ant with her short tail were crossed with the male common 
 pheasant there can be no doubt that the male hybrid off- 
 spring would have a much longer tail than that of the pure 
 offspring of the common pheasant. On the other hand, if 
 the female common pheasant, with a tail much longer than 
 that of the female Soemmerring pheasant, were crossed with 
 the male of the latter, the male hybrid offspring would 
 have a much shorter tail than that of the pure offspring of 
 Scemmerring's pheasant. * 
 
 Our fancier, in order to make his new breed with the 
 males of a pale-blue tint, and the females unchanged, 
 would have to continue selecting the males during many 
 generations; and each stage of paleness would have to be 
 fixed in the males, and rendered latent in the females. The 
 task would be an extremely difficult one, and has never 
 been tried, but might possibly be successfully carried out. 
 The chief obstacle would be the early and complete loss of 
 the pale-blue tint, from the necessity of reiterated crosses 
 with the slaty female, the latter not having at first any 
 latent tendency to produce pale-blue offspring. 
 
 On the other hand, if one or two males were to vary ever 
 so slightly in paleness, and the variations were from the 
 first limited in their transmission to the male sex, the task 
 of making a new breed of the desired kind would be easy, 
 for such males would simply have to be selected and 
 matched with ordinary females. An analogous case has 
 actually occurred, for there are breeds of the pigeon in 
 Belgium f in which the males alone are marked with black 
 
 * Temminck says that the tail of the female Phasianm Scemmer- 
 ringii is only six inches long, " Planches coloriees," vol. v, 1838, pp. 
 487, 488; the measurements above given were made for me by Mr. 
 Bclater. For the common pheasant, see Macgillivray, " Hist. Brit 
 Birds," vol. i, pp. 118-121. 
 
 fDr. Chapius, " Le Pigeon Voyageur Beige," 1865, p. 8?.
 
 508 THE DESCENT OF MAN. 
 
 striae. So again Mr. Tegetmeier has recently shown * that 
 dragons not rarely produce silver-colored birds, which are 
 almost always hens; and he himself has bred ten such 
 females. It is on the other hand a very unusual event 
 when a silver male is produced; so that nothing would be 
 easier, if desired, than to make a breed of dragons with 
 blue males and silver females. This tendency is indeed so 
 strong that when Mr. Tegetmeier at last got a silver male 
 and matched him with one cf the silver females he 
 expected to get a breed with both sexes thus colored ; he 
 was, however, disappointed, for the young male reverted to 
 the blue color of his grandfather, the young female alone 
 being silver. No doubt with patience this tendency to 
 reversion in the males, reared from an occasional silver male 
 matched with a silver hen, might be eliminated, and then 
 both sexes would be colored alike; and this very process has 
 been followed with success by Mr. Esquilant in the case of 
 silver turbits. 
 
 With fowls, variations of color, limited in their trans- 
 mission to the male sex, habitually occur. When this form 
 of inheritance prevails it might well happen that some of 
 the successive variations would be transferred to the female, 
 who would then slightly resemble the male, as actually 
 occurs in some breeds. Or again, the greater number, but 
 not all, of the successive steps might be transferred to both 
 sexes, and the female would then closely resemble the 
 male. There can hardly be a doubt that this is the cause 
 of the male pouter pigeon having a somewhat larger crop, 
 and of the male carrier pigeon having somewhat larger 
 wattles than their respective females ; for fanciers have 
 not selected one sex more than the other, and have had no 
 wish that these characters should be more strongly dis- 
 played in the male than in the female, yet this is the case 
 with both breeds. 
 
 The same process would have to be followed and the 
 same difficulties encountered if it were desired to make a 
 breed with the females alone of some new color. 
 
 Lastly, our fancier might wish to make a breed with the 
 two sexes differing from each other, and both from the 
 parent species. Here the difficulty would be extreme 
 unless the successive variations were from the first sexually 
 
 * "The Field," Sept,,
 
 BIRDS. 509 
 
 limited on both sides, and then there would be no diffi- 
 culty. We see this with the fowl; thus the two sexes of 
 the penciled Hamburghs differ greatly from each other, 
 and from the two sexes of the aboriginal Gallus lankiva; 
 and both are now kept constant to their standard of excel- 
 lence by continued selection which would be impossible 
 unless the- distinctive characters of both were limited in 
 their transmission. 
 
 The Spanish fowl offers a more curious case; the male 
 has an immense comb, but some of the successive varia- 
 tions, by the accumulation of which it was acquired, appear 
 to have been transferred to the female; for she has a comb 
 many times larger than that of the females of the parent 
 species. But the comb of the female differs in one respect 
 from that of the male, for it is apt to lop over; and within a 
 recent period it has been ordered by the fancy that this 
 should always be the case, and success has quickly followed 
 the order. ^ Now the lopping of the comb must be sexually 
 limited in its transmission, otherwise it would prevent the 
 comb of the male from being perfectly upright, which 
 would be abhorrent to every fancier. On the other hand, 
 the uprightness of the comb in the male must likewise be 
 a sexually limited character, otherwise it would prevent the 
 comb of the female from lopping over. 
 
 Prom the foregoing illustrations we see that even with 
 almost unlimited time at command it would be an ex- 
 tremely difficult and complex, perhaps an impossible pro- 
 cess, to change one form of transmission into the other 
 through selection. Therefore, without distinct evidence 
 in each case, I am unwilling to admit that this has been 
 effected in natural species. On the other hand, by means 
 of successive variations, which were from the first sexually 
 limited in their transmission, there would not be the least 
 difficulty in rendering a male bird widely different in color 
 or in any other character from the female; the latter being 
 left unaltered, or slightly altered, or specially modified for 
 the sake of protection. 
 
 - As bright colors are of service to the males in their 
 rivalry with other males, such colors would be selected 
 whether or not they were transmitted exclusively to the 
 same sex. Consequently the females might be expected 
 often to partake of the brightness of the males to a greater 
 or less degree; and this occurs with a host of species.
 
 510 THE DESCENT OF MAN. 
 
 If all the successive variations were transmitted onnallj 
 to both sexes the females would be indistinguishable from 
 the males ; and this likewise occurs with many birds. 
 If, however, dull colors were of high importance for the 
 safety of the female during incubation, as with many 
 ground birds, the females which varied in brightness 
 or which received through inheritance from the males 
 any marked accession of brightness would sooner or later 
 be destroyed. But the tendency in the males to continue 
 for an indefinite period transmitting to their female off- 
 spring their own brightness, would have to be eliminated 
 by a change in the form of inheritance; and this, as shown 
 by our previous illustration, would be extremely difficult. 
 The more probable result of the long-continued destruc- 
 tion of the more brightly colored females, supposing the 
 equal form of transmission to prevail, would be the lessen- 
 ing or annihilation of the bright colors of the males, 
 owing to their continual crossing with the duller females. 
 It would be tedious to follow out all the other possible 
 results; but I may remind the reader that if sexually lim- 
 ited variations in brightness occurred in the females, even 
 if they were not in the least injurious to them and conse- 
 quently were not eliminated, yet they would not be favored 
 or selected, for the male usually accepts any female, and 
 does not select the more attractive individuals ; conse- 
 quently these variations would be liable to be lost, and 
 would have little influence on the character of the race; and 
 this will aid in accounting for the females being commonly 
 duller-colored than the males. 
 
 In the eighth chapter instances were given, to which 
 many might here be added, of variations occurring at vari- 
 ous ages and inherited at the corresponding age It was 
 also shown that variations which occur late in life are com- 
 monly transmitted to the same sex in which they first 
 appear; while variations occurring early in life are apt to 
 be transmitted to both sexes; not that all the cases of sexu- 
 ally limited transmission can thus be accounted for. It 
 was further shown that if a male bird varied by becoming 
 brighter while young, such variations would be of no ser- 
 vice until the age for reproduction had arrived, and there 
 was competition between rival males. But in the case of 
 birds living on the ground and commonly in need of the 
 protection of dull colors, bright tints would be far more
 
 BIRDS. 511 
 
 dangerous to the young and inexperienced than to the 
 adult males. Consequently the males which varied in 
 brightness while young would suffer much destruction and 
 be eliminated through natural selection; on the other hand, 
 the males which varied in this manner when nearly mature, 
 notwithstanding that they were exposed to some additional 
 danger, might survive, and, from being favored through 
 sexual selection, Avould procreate their kind. As a relation 
 often exists between the period of variation and the form 
 of transmission, if the bright-colored young males were 
 destroyed and the mature ones were successful in their 
 courtship, the males alone would acquire brilliant colors 
 and would transmit them exclusively to their male off- 
 spring. But I by no means wish to maintain that the 
 influence of age on the form of transmission is the sole 
 cause of the great difference in brilliancy between the 
 sexes of many birds. 
 
 When the sexes of birds differ in color it is interesting 
 to determine whether the males alone have been modified 
 by sexual selection, the females having been left unchanged 
 or only partially and indirectly thus changed; or whether 
 the females have been specially modified through natural 
 selection for the sake of protection. I will, tlieref ore, dis- 
 cuss this question at some length, even more fully than its 
 intrinsic importance deserves; for various curious collateral 
 points may thus be conveniently considered. 
 
 Before we enter on the subject of color, more especially 
 in reference to Mr. Wallace's conclusions, it may be 
 useful to discuss some other sexual differences under a similar 
 point of view. A breed of fowls formerly existed in Ger- 
 many* in which the hens were furnished with spurs; they 
 were good layers, but they so greatly disturbed their nests 
 with their spurs that they could not be allowed to sit on 
 their own eggs. Hence at one time it appeared to me 
 probable that with the females of the wild Gallinaceae the 
 development of spurs had been checked through natural 
 selection from the injury thus caused to their nests. This 
 seemed all the more probable, as wing-spurs, which would 
 not be injurious during incubation, are often as well 
 developed in the female as in the male; though in not a 
 
 Bechstein, " Naturgescli. Deutschlands," 1793, B. iii, s. 339.
 
 512 THE DESCENT OF MAN. 
 
 few cases they are rather larger in the male. When th 
 male is furnished with leg-spurs the female almost always 
 exhibits rudiments of them the rudiment sometimes con- 
 sisting of a mere scale, as in Gallus. Hence it might be 
 argued that the females had aboriginally been furnished 
 with well-developed spurs, but that these had subsequently 
 been lost through disuse or natural selection. But if this 
 view be admitted it would have to be extended to innumer- 
 able other cases; and it implies that the female progenitors 
 of the existing spur-bearing species were once incumbered 
 with an injurious appendage. 
 
 In some few genera and species, as in Galloperdix, 
 Acomus and the Javan peacock (Pavo muticus), the 
 females, as well as the males, possess well-developed leg- 
 spurs. Are we to infer from this fact that they construct 
 a different sort of nest from that made by their nearest 
 allies, and not liable to be injured by their spurs, so that 
 the spurs have not been removed ? Or are we to suppose 
 that the females of these several species especially require 
 spurs for their defense ? It is a more probable conclusion 
 that both the presence and absence of spurs in the females 
 result from different laws of inheritance having prevailed, 
 independently of natural selection. With the many 
 females in which spurs appear as rudiments we may con- 
 clude that some few of the successive variations, through 
 which they were developed in the males, occurred very 
 early in life and were consequently transferred to the 
 females. In the other and much rarer cases in which the 
 females possess fully developed spurs we may conclude 
 that all the successive variations were transferred to them; 
 and that they gradually acquired and inherited the habit 
 of not disturbing their nests. 
 
 The vocal organs and the feathers variously modified for 
 producing sound, as well as the proper instincts for using 
 them, often differ in the two sexes, but are sometimes the 
 same in both. Can such differences be accounted for by the 
 males having acquired these organs and instincts, while the 
 females have been saved from inheriting them, on account 
 of the danger to which they would have been exposed by 
 attracting the attention of birds or beasts of prey? This 
 does not seem to me probable, when we think of the 
 multitude of birds which with impunity gladden the
 
 BIRDS. 513 
 
 country with their voices during the spring. * It is a safer con- 
 clusion that, as vocal and instrumental organs are of special 
 service only to the males during their courtship, these 
 organs were developed through sexual selection and their 
 constant use in that sex alone the successive variations 
 and the effects of use having been from the first more or less 
 limited in transmission to the male offspring. 
 
 Many analogous cases could be adduced ; those, foi 
 instance, of the plumes on the head being generally longer 
 in the male than in the female, sometimes of equal length 
 in both sexes, and occasionally absent in the female these 
 several cases occurring in the same group of birds. It 
 would be difficult to account for such a difference between 
 the sexes by the female having been benefited by possessing 
 a slightly shorter crest than the male, and its consequent 
 diminution or complete suppression through natural selec- 
 tion. But I will take a more favorable case, namely, the 
 length of the tail. The long train of the peacock would 
 have been not only inconvenient but dangerous to the 
 peahen during the period of incubation and while accom- 
 panying her young. Hence, there is not the least a priori 
 improbability in the development of her tail having been 
 checked through natural selection. But the females of 
 various pheasants, which apparently are exposed on their 
 open nests to as much danger as the peahen, have tails of 
 considerable length. The females as well as the males of 
 the Menura superset have long tails, and they build a 
 domed nest, which is a great anomaly in so large a bird. 
 Naturalists have wondered how the female menura could 
 manage her tail during incubation; but it is now known f 
 that she " enters the nest head first, and then turns round, 
 with her tail sometimes over her back, but more often bent 
 round by her side. Thus in time the tail becomes quite 
 askew, and is a tolerable guide to the length of time the 
 bird has been sitting." Both sexes of an Australian king- 
 fisher (Tanysiptera sylvia\ have the middle tail-feathers 
 greatly lengthened, and tne female makes her nest in a 
 
 *Daines Barrington, however, thought it probable (" Phil. Trans- 
 act.," 1773, p. 164) that few female birds sing, because the talent 
 would have been dangerous to them during incubation. He adds 
 that a similar view may possibly account for the inferiority of the 
 female to the male in plumage. 
 
 fMr. Ramsay, in " Proc. Zoolog. Soc.," 1868, p. 50.
 
 514 THE DESCENT OF MAN. 
 
 hole; and, as I am informed by Mr. R. B. Sharpe, these 
 feathers become much crumpled during incubation. 
 
 In these two latter cases the great length of the tail- 
 feathers must be in some degree inconvenient to the female; 
 and as in both species the tail-feathers of the female are 
 somewhat shorter than those of the male, it might be 
 argued that their full development had been prevented 
 through natural selection. But if the development of the 
 tail of the peahen had been checked only when it became 
 incorveniently or dangerously great she would have retained 
 a much longer tail than she actually possesses; for her tail 
 is not nearly so long, relatively to the size of her body, as 
 that of many female pheasants, nor longer than that of 
 the female turkey. It must also be borne in mind that, in 
 accordance with this view, as soon as the tail of the peahen 
 became dangerously long, and its development was conse- 
 quently checked, she would have continually reacted on her 
 male progeny, and thus have prevented the peacock from 
 acquiring his present magnificent train. We may, there- 
 fore, infer that the length of the tail in the peacock and 
 its shortness in the peahen are the result of the requisite 
 variations in the male having been from the first trans- 
 mitted to the male offspring alone. 
 
 We are led to a nearly similar conclusion with respect to 
 the length of the tail in the various species of pheasants. 
 In the eared pheasant (Crossoptilon aicrituni) the tail is of 
 equal length in both sexes, namely, sixteen or seventeen 
 inches; in the common pheasant it is about twenty inches 
 long in the male and twelve in the female; in Scemmerring's 
 pheasant, thirty-seven inches in the male and only eight in 
 the female; and lastly, in Reeve's pheasant it is sometimes 
 actually seventy-two inches long in the male and sixteen 
 in the female. Thus in the several species the tail of the 
 female differs much in length irrespectively of that of the 
 male; and this can be accounted for, as it seems to me, 
 with much more probability, by the laws of inheritance 
 that is, by the successive variations having been from the 
 first more or less closely limited in their transmission to 
 the male sex than by the agency of natural selection, 
 resulting from the length of tail being more or less injuri- 
 ous to the females of these several allied species. 
 
 We may now consider Mr. Wallace's arguments in regard
 
 BIRDS. 515 
 
 to the sexual coloration of birds. He believes that the 
 bright tints originally acquired through sexual selection by 
 the males would in all, or almost all cases, have been trans- 
 mitted to the females, unless the transference had been 
 checked through natural selection. I -may here remind 
 the reader that various facts opposed to this view have 
 already been given under reptiles, amphibians, fishes and 
 lepidoptera. Mr. "Wallace rests his belief chiefly, but not 
 exclusively, as we shall see in the next chapter, on the fol- 
 lowing statement,* that when both sexes are colored in a 
 very conspicuous manner the nest is of such a nature as to 
 conceal the sitting bird; but when there is a marked con- 
 trast of color between the sexes, the male being gay and 
 the female dull colored, the nest is open and exposes the 
 sitting bird to vieAV. This coincidence, as far as it goes, 
 certainly seems to favor the belief that the females which 
 sit on open nests have been specially modified for the sake 
 of protection; but we shall presently see that there is an- 
 other and more probable explanation, namely, that con- 
 spicuous females have acquired the instinct of building 
 domed nests oftener than dull-colored birds. Mr. Wallace 
 admits that there are, as might have been expected, some 
 exceptions to his two rules, but it is a question whether 
 the exceptions are not so numerous as seriously to invalidate 
 them. 
 
 There is, in the first place, much truth in the Duke of 
 Argyll's remark f that a large domed nest is more con- 
 spicuous to an enemy, especially to all tree-haunting carniv- 
 orous animals, than a smaller open nest. Nor must we 
 forget that with many birds which build open nests the 
 male sits on the eggs and aids the female in feeding the 
 young; this is the case, for instance, with Pyranga cestiva,% 
 one of the most splendid birds in the United States, the 
 male being vermilion and the female light brownish-green. 
 Now if brilliant colors had been extremely dangerous to 
 birds while sitting on their open nests the males in these 
 cases would have suffered greatly. It might, however, be 
 of such"paramouut importance to the male to be brilliantly 
 colored in order to beat his rivals that this may have more 
 than compensated some additional danger. 
 
 *" Journal of Travel," edited by A. Murray, vol. i, 1868, p. 78. 
 f "Journal of Travel," edited by A. Murray, vol. i, 1868, p. 281. 
 jAudubon, " Ornithological Biography,-" vol. i, p. 233-
 
 516 THE DESCENT OF MAN. 
 
 Mr. "Wallace admits that with the king- crows (Dicrurus), 
 orioles, and Pittidse, the females are conspicuously colored, 
 yet build open nests; but he urges that the birds of the first 
 group are highly pugnacious and could defend themselves; 
 that those of the second group take extreme care in con- 
 cealing their open nests, but this does not invariably hold 
 good;* and that with the birds of the third group the 
 females are brightly colored, chiefly on the under surface. 
 Besides these cases, pigeons, which are sometimes brightly 
 and almost always conspicuously colored, and which are 
 notoriously liable to the attacks of birds of prey, offer a 
 serious exception to the rule, for they almost always build 
 open and exposed nests. In another large family, that of 
 the humming-birds, all the species build open nests, yet 
 with some of the most gorgeous species the sexes are alike; 
 and in the majority, the females, though less brilliant than 
 the males, are brightly colored. Nor can it be maintained 
 that all female humming - birds, which are brightly 
 colored, escape detection by their tints being green, for 
 some display on their upper surfaces red, blue and other 
 colors, f 
 
 In regard to birds which build in holes or construct 
 domed nests, other advantages, as Mr. Wallace remarks, 
 besides concealment, are gained, such as shelter from the 
 rain, greater warmth, and in hot countries protection from 
 the sun;J so that it is no valid objection to his view that 
 many birds having both sexes obscurely colored build con- 
 cealed nests. The female horn-bill (Buceros), for instance, 
 
 *Jerdon, "Birds of India," vol. ii., p. 108. Gould's "Hand-book 
 of the Birds of Australia," vol. i., p. 463. 
 
 ( For instance, the female Eupetomcna macroura has the head and 
 tail dark blue with reddish loins; the female Lampornis porpJiyru- 
 rus is blackish green on the upper surface, with the lores and sides 
 of the throat crimson; the female Eulampis jugularis has the top of 
 the head and back green, but the loins and the tail are crimson. 
 Many other instances of highly conspicuous females could be given. 
 Seo Mr. Gould's magnificent work on this family. 
 
 t Mr. Salvin noticed in Guatemala (" Ibis," 1864, p. 375) that hum- 
 ming-birds were much more unwilling to leave their nests during 
 very hot weather, when the sun was shining brightly, as if their 
 eggs would be thus injured, than during cool, cloudy or rainy 
 weather. 
 
 1 may specify, as instances of dull colored birds building con- 
 cealed nests, the species belonging to eight Australian genera 
 described in Gould's " Hand-book to the Birds of Australia," vol. i, 
 pp. 340, 362, 365, 383, 387, 389, 391, 414.
 
 BIRDS. 517 
 
 of India and Africa, is protected during incubation with 
 extraordinary care, for she plasters up with her own excre- 
 ment the orifice of the hole in which she sits on her eggs, 
 leaving only a small orifice through which the male feeds 
 her; she is thus kept a close prisoner during the whole 
 period of incubation;* yet female horn-bills are not more 
 conspicuously colored than many other birds of equal size 
 which build open nests. It is a more serious objection to 
 Mr. Wallace's view, as is admitted by him, that in some few 
 groups the males are brilliantly colored and the females 
 obscure, and yet the latter hatch their eggs in domed nests. 
 This is the case with the Grallinae of Australia, the superb 
 warblers (Maluridae) of the same country, the sun-birds 
 (NectariniEe), and with several of the Australian honey- 
 suckers or Meliphagidae. f 
 
 If we look to the birds of England we shall see that 
 there is no close and general relation between the colors of 
 the female and the nature of the nest which is constructed. 
 About forty of our British birds (excluding those of 
 large size which could defend themselves) build in holes in 
 banks, rocks or trees or construct domed nests. If we take 
 the colors of the female goldfinch, bullfinch or blackbird 
 as a standard of the degree of conspicuousness, which is 
 not highly dangerous to the sitting female, then out of the 
 above forty birds the females of only twelve can be consid- 
 ered as conspicuous to a dangerous degree, the remaining 
 twenty - eight being inconspicuous. J Nor is there any 
 
 *Mr. C. Home, "Proc. Zoolog. Soc.," 1869, p. 243. 
 
 f On the nidification and colors of these latter species, see Gould's 
 "Hand-book," etc., vol. i, pp. 504, 527. 
 
 1 1 have consulted, on this subject, Macgillivray's "British Birds/'' 
 and though dr ubts may be entertained in some cases in regard to the 
 degree of concealment of the nest and to the degree of conspicuous- 
 ness of the female, yet the following birds, which all lay their eggs 
 in holes or in domed nests, can hardly be considered, by the above 
 standard, as conspicuous: Passer 2 specie, Sturnus, of which the 
 female is considerably less brilliant than the male; Cinclus: Motal- 
 lica boarula (?); Erith..cus (?); Fruticola, 2 sp. Saxicola; Ruticilla, 2 
 -sp.; Sylvia, 3 sp.; Parus, 3 sp.; Mecistura; Anorthura; Certhia; 
 Sitta; Yunx; Muscicapa, 2 sp. ; Hirundo, 3 sp. ; and Cypselus. The 
 females of the following 12 birds may be considered as conspicuous 
 according to the same standard, viz., Pastor, Motacilla alba, Parus 
 major and P. cseruleus, Upupa, Picus, 4 sp., Coracias, Alcedo and 
 Merops.
 
 518 THE DESCENT OF MAN, 
 
 close relation within the same genus between a vftlf-pro- 
 nounced difference in color between the sexes and the 
 nature of the nest constructed. Thus the mnle house- 
 
 rrrow (Passer domesticus) differs much from the female, 
 male tree-sparrow (P. montaims] hardly at, all, and yet 
 both build well-concealed nests. The two sexes of the 
 common fly-catcher (Muscicapa grisola] can hardly be 
 distinguished, while the sexes of the pied fly -catcher 
 {M. luctuosa) differ considerably, and both species build 
 in holes or conceal their nests. The female blackbird 
 (Turdus merula) differs much, the female ring-ouzel (T. 
 torquatus) differs less, and the female common thrush 
 (T. musicus) hardly at all from their respective males; yet 
 all build open nests. On the other hand, the not very 
 distantly allied water-ouzel (Cinclus aquaiicus) builds a 
 domed nest, and the sexes differ about as much as in the 
 ring-ouzel. The black and red grouse (Tetrao tetrix and 
 T. sections') build open nests in equally well-concealed 
 spots, but in the one species the sexes differ greatly, and. 
 in the other very little. 
 
 Notwithstanding the foregoing objections, I cannot 
 doubt, after reading Mr. Wallace's excellent essay, that 
 looking to the birds of the world a large majority of the 
 species in which the females are conspicuously colored (and 
 in this case the males with rare exceptions are equally 
 conspicuous) build concealed nests for the sake of protec- 
 tion. Mr. Wallace enumerates* a long series of groups in 
 which this rule holds good; but it will suffice here to give 
 as instances the more familiar groups of kingfishers, tou- 
 cans, trogons, puff -birds (Capitonida?), plantain - eaten 
 (Musophagae), woodpeckers and parrots. Mr. Wallace 
 believes that in these groups, as the males gradually ac- 
 quired through sexual selection their brilliant colors, these 
 were transferred to the females and were not eliminated b;y 
 natural selection owing to the protection which they already 
 enjoyed from their manner of nidification. According to 
 this view, their present manner of nesting was acquired 
 before their present colors. But it seems to me much 
 more probable that in most cases, as the females were 
 gradually rendered more and more brilliant from partaking 
 of the colors of the male, they were gradually led to change 
 
 * "Journal of Travel," edited by A. Murray, vol. i, p. 78.
 
 BIRDS. 519 
 
 their instincts (supposing that they originally built open 
 nests) and to seek protection by building domed or con- 
 cealed nests. No one who studies, for instance, Audubon's 
 account of the differences in the nests of the same species 
 in the Northern and Southern United States,* will feel 
 any great difficulty in admitting that birds, either by a 
 change (in the strict sense of the word) of their habits, or 
 through the natural selection of so-called spontaneous 
 variations of instinct, might readily be led to modify their 
 manner of nesting. 
 
 This way of viewing the relation, as far as it holds good, 
 between the bright colors of female birds and their manner 
 of nesting receives some support from certain cases occur- 
 ring in the Sahara Desert. Here, as in most other deserts, 
 various birds and many other animals have had their colors 
 adapted in a wonderful manner to the tints of the surround- 
 ing surface. Nevertheless there are, as I am informed by 
 the Eev. Mr. Tristram, some curious exceptions to the rule; 
 thus the male of the Monticola cyanea is conspicuous from 
 his bright-blue color, and the female almost equally con- 
 spicuous from her mottled brown and white plumage; both 
 sexes of two species of Dromolasa are of a lustrous black; so 
 that these three species are far from receiving protection 
 from their colors, yet they are able to survive, for they have 
 acquired the habit of taking refuge from danger in holes 
 or crevices in the rocks. 
 
 With respect to the above groups in which the females 
 are conspicuously colored and build concealed nests, it is 
 not necessary to suppose that each separate species had its 
 nidifying instinct specially modified; but only that the 
 early progenitors of each group were gradually led to build 
 domed or concealed nests, and afterward transmitted this 
 instinct, together with their bright colors, to their modified 
 descendants. As far as it can be trusted the conclusion is 
 interesting, that sexual selection, together with equal or 
 nearly equal inheritance by both sexes, have indirectly 
 determined the manner of nidification of whole groups of 
 birds. 
 
 According to Mr. Wallace, even in the groups in which 
 
 * See many statements in the "Ornithological Biography." See 
 also some curious observations on the nests of Italian birds by 
 Eugenio Bettoni, in the " Atti deila Societa Italiana," vol. xi, 1869, 
 V. 7,
 
 520 THE DESCENT OF MAN. 
 
 the females, from being protected in domed nests during 
 incubation, have not had their bright colors eliminated 
 through natural selection, the males often differ in a slight 
 and occasionally in a considerable degree from the females. 
 This is a significant fact, for such differences in color must be 
 accounted for by some of the variations in the males having 
 been from the first limited in transmission to the same sex; 
 as it can hardly be maintained that these differences, espe- 
 cially when very slight, serve as a protection to the female. 
 Thus all the species in the splendid group of the Trogons 
 build in holes; and Mr. Gould gives figures * of both sexes 
 of twenty-five species, in all of which, with one partial 
 exception, the sexes differ sometimes slightly, sometimes 
 conspicuously in color the males being always finer than 
 the females, though the latter are likewise beautiful. All 
 the species of king-fishers build in holes, and with most of the 
 species the sexes are equally brilliant, and thus far Mr. Wal- 
 lace's rule holds good; but in some of the Australian species 
 the colors of the females are rather less vivid than those 
 of the male ; and in one splendidly colored species the 
 sexes differ so much that they were at first thought to be 
 specifically distinct, f Mr. R. B. Sharpe, who has espe- 
 cially studied this group, has shown me some American 
 species (Ceryle) in which the breast of the male is belted 
 with black. Again, in Carcineutes, the difference between 
 the sexes is conspicuous; in the male the upper surface is 
 dull-blue banded with black, the lower surface being partly 
 fawn-colored, and there is much red about the head; in the 
 female the upper surface is reddish-brown banded with 
 black, and the lower surface white with black markings. 
 It is an interesting fact, as showing how the same peculiar 
 style of sexual coloring often characterizes allied forms, 
 that in three species of Dacelo the male differs from the 
 female only in the tail being dull- 1 ' ue banded with black, 
 while that of the female is brown with blackish bars; so 
 that here the tail differ^ in color in the two sexes in exactly 
 the same manner as the whole upper surface in the two 
 sexes of Carcineutes. 
 
 With parrots, which likewise build in holes, we find 
 
 * See his " Monograph of the Trogonidae, " first edition, 
 t Namely Cyanalcyon. Gould's "Hand-book to the Birds of Aus- 
 tralia." vol. i, p. 183; see also pp. 130, 136.
 
 BIRDS. 521 
 
 analogous cases; in most of the species both sexes are 
 brilliantly colored and indistinguishable, but in not a few 
 species the males are colored rather more vividly than the 
 females, or even very differently from them. Thus, besides 
 other strongly marked differences, the whole under surface 
 of the male king lory (Aprosmictus scapulatus) is scarlet, 
 while the throat and chest of the female is green tinged 
 with red; in the Euphema splendida there is a similar dif- 
 ference, the face and wing coverts moreover of the female 
 being of a paler blue than in the male. * In the family of the 
 tits (Farina), which build concealed nests, the female 
 of our common blue tomtit (Parus ccBruleus) is "much 
 less brightly colored " than the male ; and in the 
 magnificent Sultan yellow tit of India the difference is 
 greater, f 
 
 Again, in the great group of the woodpeckers, J the sexes 
 are generally nearly alike, but in the Megapicus validus all 
 those parts of the head, neck and breast which are crimson 
 in the male are pale-brown in the female. As in several 
 woodpeckers the head of the male is bright crimson, while 
 that of the female is plain, it occurred to me that this color 
 might possibly make the female dangerously conspicuous 
 whenever she put her head out of the hole containing her 
 nest, and consequently that this color, in accordance with 
 Mr. Wallace's belief, had been eliminated. This view is 
 strengthened by what Malherbe states with respect to 
 Indopicus carlotta; namely, that the young females, like the 
 young males, have some crimson about their heads, but that 
 this color disappears in the adult female, while it is intensi- 
 fied in the adult male. Nevertheless, the following con- 
 siderations render this view extremely doubtful ; the male 
 takes a fair share in incubation, and would be thus almost 
 equally exposed to danger; both sexes of many species have 
 their heads of an equally bright crimson; in other species 
 
 * Every gradation of difference between the sexes may be followed 
 in the parrots of Australia. See Gould's " Hand-book," etc., vol. ii, 
 pp. 14-102. 
 
 ' f Mac'gillivray's "British Birds," vol. ii, p. 433. Jerdon, "Birds 
 of India," vol. ii, p. 282. 
 
 \ All the following facts are taken from M. Malherbe's magnificent 
 "Monographic des Picidees," 1861. 
 
 SAudubons "Ornithological Biography," vol. ii, p. 75; see also 
 the Ibis," vol. i, p. 268.
 
 522 THE DESCENT OF MAN. 
 
 the difference between the sexes in the amount of scarlet is 
 so slight that it can hardly make any appreciable difference 
 in the danger incurred; and lastly, the coloring of the 
 head in the two sexes often differs slightly in other ways. 
 
 The cases, as yet given, of slight and graduated differ- 
 ences in color between the males and females in the groups, 
 in which, as a general rule, the sexes resemble each other, 
 all relate to species which build domed or concealed nests. 
 But similar gradations may likewise be observed in groups 
 in which the sexes as a general rule resemble each other, 
 but which build open nests. 
 
 As I have before instanced the Australian parrots, so I 
 may here instance, without giving any details, the Austra- 
 lian pigeons.* It deserves especial notice that in all these 
 cases the slight differences in plumage between the sexes 
 are of the same general nature as the occasionally greater 
 differences. A good illustration of this fact has already 
 been afforded by those kingfishers in which either the tail 
 alone or the whole upper surface of the plumage differs in 
 the same manner in the two sexes. Similar cases may be 
 observed with parrots and pigeons. The differences in color 
 between the sexes of the same species are, also, of the same 
 general nature as the differences in color between the dis- 
 tinct species of the same group. For when in a group in 
 which the sexes are usually alike the male differs considera- 
 bly from the female he is not colored in a quite new style. 
 Hence we may infer that within the same group the special 
 colors of both sexes when they are alike, and the colors of 
 the male when he differs slightly or even considerably from 
 the female, have been in most cases determined by the same 
 general cause; this being sexual selection. 
 
 It is not probable, as has already been remarked, that 
 differences in color between the sexes, when very slight, 
 can be of service to the female as a protection. Assuming, 
 however, that they are of service, they might be thought to 
 be cases of transition; but we have no reason to believe that 
 many species at any one time are undergoing change. 
 Therefore we can hardly admit that the numerous females 
 which differ very slightly in color from their males are now 
 all commencing to become obscure for the sake of protection. 
 
 * Gould's " Hand-book to the Birds of Australia," vol. ii, pp. 
 109-149.
 
 BIRDS. 523 
 
 Even if we consider somewhat more marked sexual differ- 
 ences, is it probable, for instance, that the head of the 
 female chaffinch, the crimson on the breast of the female 
 bullfinch, the green of the female greenfinch, the crest of 
 the female golden-crested wren have all been rendered less 
 bright by the slow process of selection for the sake of pro- 
 tection ? I cannot think so; and still less with the slight 
 differences between the sexes of those birds which build 
 concealed nests. On the other hand, the differences in 
 color between the sexes, whether great or small, may to a 
 large extent be explained on the principle of the successive 
 variations acquired by the males through sexual selection, 
 having been from the first more or less limited in their 
 transmission to the females. That the degree of limitation 
 should differ in different species of the same group will not 
 surprise any one who has studied the laws of inheritance, 
 for they are so complex that they appear to us in our igno- 
 rance to be capricious in their actions.* 
 
 As far as I can discover there are few large groups of 
 birds in which all the species have both sexes alike and 
 brilliantly colored, but I hear from Mr. Sclater that this ' 
 appears to be the case with the Musophagae or plantain- 
 eaters. Nor do I believe that any large group exists in 
 which the sexes of all the species are widely dissimilar in 
 color. Mr. Wallace informs me that the chatterers of 
 South America ( Cotingidce) offer one of the best instances; 
 but with some of the species in which the male has a splen- 
 did red breast the female exhibits some red on her breast; 
 and the females of other species show traces of the green 
 and other colors of the males. Nevertheless we have a 
 near approach to close sexual similarity or dissimilarity 
 throughout several groups; and this, from what has ;just 
 been said of the fluctuating nature of inheritance, is a 
 somewhat surprising circumstance. But that the same 
 laws should largely prevail with allied animals is not sur- 
 prising. The domestic fowl has produced a great number 
 of breeds and sub-breeds, and in these the sexes generally 
 differ in plumage; so that it has been noticed as an un- 
 usual circumstance when in certain sub -breeds they 
 resemble each other. On the other hand, the domestic 
 
 * See remarks to this effect in my work on " Variation uudei 
 Domestication," vol. ii, chap. xii.
 
 524 THE DESCENT OF MAN. 
 
 pigeon has likewise produced a vast number of distinct 
 breeds and sub-breeds, and in these, with rare exceptions, 
 the two sexes are identically alike. 
 
 Therefore if other species of Gallus and Columba were 
 domesticated and varied it would not be rash to predict 
 that similar rules of sexual similarily and dissimilarity 
 depending on the form of transmission would hold good in 
 both cases. In like manner the same form of transmission 
 has generally prevailed under nature throughout the same 
 groups, although marked exceptions to this rule occur. 
 Thus within the same family, or even genus, the sexes may 
 be identically alike or very different in color. Instances 
 have already been given in the same genus, as with spar- 
 rows, fly-catchers, thrashes and grouse. In the family of 
 pheasants the sexes of almost all the species are wonder- 
 fully dissimilar, but are quite alike in the eared pheasant 
 or Crossoptilon auritum. In two species of Chloephaga, 
 a genus of geese, the male cannot be distinguished from 
 the females except by size; while in two others the sexes 
 are so unlike that they might easily be mistaken for distinct 
 species.* 
 
 The laws of inheritance can alone account for the fol- 
 lowing cases in which the female acquires late in life 
 certain characters proper to the male, and ultimately 
 comes to resemble him more or less completely. Here pro- 
 tection can hardly have come into play. Mr. Blyth in- 
 forms me that the females of Oriolus melanocepJialus and 
 of some allied species when sufficiently mature to breed 
 differ considerably in plumage from the adult males; but 
 after the second or third moults they differ only in their 
 beaks having a slight greenish tinge. In the dwarf bitterns 
 (Ardetta), according to the same authority, " the male 
 acquires his final livery at the first moult; the female not 
 before the third or fourth moult; in the meanwhile she pre- 
 sents an intermediate garb, which is ultimately exchanged 
 for the same livery as that of the male." So, again, the 
 female Falco peregrinus acquires her blue plumage more 
 slowly than the male. Mr. Swinhoe states that with one of 
 the drongo shrikes (Dicrurus macrocercus) the male, while 
 almost a nestling, molts his soft brown plumage and 
 becomes of a uniform glossy greenish-black; but the female 
 
 *The " T bis," vol. vi, 1864, p. 122.
 
 BIRDS. 525 
 
 retains for a long time the Avhite striae and spots on the 
 axillary feathers; and does not completely assume the uni- 
 form black color of the male for three years. The same 
 excellent observer remarks that in the spring of the 
 second year the female spoon-bill (Platalea) of China 
 resembles the male of the first year, and that apparently it 
 is not until the third spring that she acquires the same 
 adult plumage as that possessed by the male at a much 
 earlier age. The female Bombycilla carolinensis differs 
 very little from the male, but the appendages, which like 
 beads of red sealing-wax ornament the wing-feathers,* are 
 not developed in her so early in life as in the male. In the 
 male of an Indian paroquet (Palceornis javanicus) the 
 upper mandible is coral-red from his earliest youth, but in 
 the female, as Mr, Blyth has observed with caged and wild 
 birds, it is at first black and does not become red until the 
 bird is at least a year old, at which age the sexes resemble 
 each other in all respects. Both sexes of the wild turkey 
 are ultimately furnished with a tuft of bristles on the 
 breast, but in two-year-old birds the tuft is about four 
 inches long in the male and hardly apparent in the female; 
 when, however, the latter has reached her fourth year, it is 
 from four to five inches in length, f 
 
 These cases must not be confounded with those where 
 diseased or old females abnormally assume masculine char- 
 acters, nor with those where fertile females, while young, 
 acquire the characters of the male, through variation or 
 some unknown cause. J But all these cases have so much 
 
 * When the male courts the female, these ornaments are vibrated, 
 and " are shown off to great advantage," on the outstretched wings; 
 A. Leith Adams, "Field and Forest Rambles/' 1873, p. 153. 
 
 f On Ardetta, Translation of Cuvier's "Regne Animal," by Mr. 
 Blyth, foot note p. 159. On the Peregrine Falcon, Mr. Blyth, in 
 Oharlesworth's "Mag. of Nat. Hist.," vol. i, 1837, p. 304. On 
 Dicrurus, " Ibis," 1863, p. 44, On the Platalea, " Ibis," vol. vi, 1864, 
 p 366 On the Bombycilla, Audubon's " Ornitholog. Biography," 
 vol. i, p. 229. On the Palaeornis, see, also, Jerdon, " Birds of India," 
 vol. i, p. 263. On the wild turkey, Audubon, ibid, vol. i, p. 15; but 
 I hear from Judge Caton that in Illinois the female very rarely 
 acquires a tuft. Analogous cases with the females of Petrocossyphus 
 are given by Mr. R. Sharpe, " Proc. Zoolog. Soc.," 1872, p. 496. 
 
 JOf these latter cases Mr. Blyth has recorded (Translation of 
 Cuvier's "Regne Animal," p. 158) various instances with Lanius, 
 Ruticilla, Linaria and Anas. Audubon has also recorded a similar 
 case (" Ornith. Biog.," vol. v, p. 519) with Pyranga wsti'oa.
 
 526 THE DESCENT OF MAN. 
 
 in common that they depend, according to the hypothesis 
 of pangenesis, on gemmules derived from each part of the 
 male being present, though latent, in the female; their 
 development following on some slight change in the elective 
 affinities of her constituent tissues. 
 
 A few words must be added on changes of plumage in 
 relation to the season of the year. From reasons formerly 
 assigned there can be little doubt that the elegant plumes, 
 long pendant feathers, crests, etc., of egrets, herons and 
 many other birds, which are developed and retained only 
 during the summer, serve for ornamental and nuptial pur- 
 poses, though common to both sexes. The female is thus ren- 
 dered more conspicuous during the period of incubation than 
 during the winter ; but such birds as herons and egrets 
 would be able to defend themselves. As, however, plumes 
 would probably be inconvenient and certainly of no use 
 during the winter, it is possible that the habit of moulting 
 twice in the year may have been gradually acquired through 
 natural selection for the sake of casting off inconvenient 
 ornaments during the winter. But this view cannot be 
 extended to the many waders, whose summer and winter 
 plumages differ very little in color. With defenseless spe- 
 cies, in which both sexes, or the males alone, become 
 extremely conspicuous during the breeding-season or 
 when the males acquire at this season such long wing or 
 tail feathers as to impede their flight, as with Cosmetornis 
 and Vidua it certainly at first appears highly probable 
 that the second moult has been gained for the special pur- 
 pose of throwing off these ornaments. We must, however, 
 remember that many birds, such as some of the birds of 
 paradise, the Argus pheasant and peacock, do not cast 
 their plumes during the winter; and it can hardly be 
 maintained that the constitution of these birds, at least of 
 the Gallinaceae, renders a double moult impossible, for the 
 ptarmigan moults thrice in the year.* Hence it must be 
 considered as doubtful whether the many species which 
 moult their ornamental plumes or lose their bright colors 
 during the winter, have acquired this habit on account of 
 the inconvenience or danger which they would otherwise 
 have suffered. 
 
 * See Gould's " Birds of Great Britain."
 
 BIRDS. 527 
 
 I conclude, therefore, that the habit of moulting twice 
 in the year was in most or all cases first acquired for some 
 distinct purpose, perhaps for gaining a warmer winter cov- 
 ering; and that variations in the plumage occurred during 
 the summer were accumulated through sexual selection, 
 and transmitted to the offspring at the same season of the 
 year ; that such variations were inherited either by both 
 sexes or by the males alone, according to the form of inher- 
 itance which prevailed. This appears more probable than 
 that the species in all cases originally tended to retain 
 their ornamental plumage during the winter, but were 
 saved from this through natural selection, resulting from 
 the inconvenience or danger thus caused. 
 
 I have endeavored in this chapter to show that the argu- 
 ments are not trustworthy in favor of the view that weap- 
 ons, bright colors, and various ornaments are now confined 
 to the males owing to the conversion, by natural selection, 
 of the equal transmission of characters to both sexes, into 
 transmission to the male sex alone. It is also doubtful 
 whether the colors of many female birds are due to the 
 preservation, for the sake of protection, of variations 
 which were from the first limited in their transmission to 
 the female sex. But it will be convenient to defer any 
 further discussion on this subject until I treat, in the fol- 
 lowing chapter, of the differences in plumage between the 
 young and old.
 
 528 THE DESCENT OF MAN. 
 
 CHAPTEK XVI. 
 BIRDS concluded. 
 
 The immature plumage in relation to the character of the plumage in 
 both sexes when adult Six classes of cases Sexual differences 
 between the males of closely allied or representative species 
 The female assuming the characters of the male Plumage of 
 the young in relation to the summer and winter plumage of the 
 adults On the increase of beauty in the birds of the world 
 Protective coloring Conspicuously colored birds Novelty appre- 
 ciated Summary of the four chapters on birds. 
 
 WE must now consider the transmission of characters as 
 limited by age, in reference to sexual selection. The truth 
 and importance of the principle of inheritance at corre- 
 sponding ages need not here be discussed, as enough has 
 already been said on the subject. Before giving the several 
 rather complex rules or classes of cases under which the 
 differences in plumage between the young and the old, as 
 far as known to me, may be included, it will be well to 
 make a few preliminary remarks. 
 
 With animals of all kinds, when the adults differ in color 
 from the young, and the colors of the latter are not, as far 
 as we can see, of any special service, they may generally 
 be attributed, like various embryological structures, to the 
 retention of a former character. But this view can be 
 maintained with confidence only when the young of several 
 species resemble each other closely, and likewise resemble 
 other adult species belonging to the same group; for the latter 
 are the living proofs that such a state of things was formerly 
 possible. Young lions and pumas are marked with feeble 
 stripes or rows of spots, and as many allied species both 
 young and old are similarly marked no believer in evolution 
 will doubt that the progenitor of the lion and puma was a 
 striped animal, and that the young have retained vestiges 
 of the stripes like the kittens of black cats, which are not 
 in the least striped when grown up. Many species of deer,
 
 BIRDS. 529 
 
 which when mature are not spotted, are while young cov- 
 ered with white spots, as are likewise some few species in the 
 adult state. So again the young in the whole family of 
 pigs (Suidae), and in certain rather distantly allied animals, 
 such as the tapir, are marked with dark longitudinal 
 stripes; but here we have a character apparently derived 
 from an extinct progenitor, and now preserved by the young 
 alone. In all such cases the old have had their colors 
 changed in the course of time, while the young have 
 remained but little altered, and this has been effected 
 through the principle of inheritance at corresponding ages. 
 This same principle applies to many birds belonging to 
 various groups in which the young closely resemble each 
 other, and differ much from their respective adult parents. 
 The young of almost all the Gallinaceae and of some distantly 
 allied birds, such as ostriches, are covered with longitu- 
 dinally striped down; but this character points back to a 
 state of things so remote that it hardly concerns us. Young 
 cross-bills (Loxia) have at first straight beaks like those of 
 other finches, and in their immature striated plumage they 
 resemble the mature redpole and female siskin, as well as the 
 young of the goldfinch, greenfinch and some other allied 
 species. The young of many kinds of buntings (Emberiza) 
 resemble one another, and likewise the adult states of the 
 common bunting, E. miliaria. In almost the whole large 
 group of thrushes the young have their breasts spotted a 
 character which is retained throughout life by many 
 species, but is quite lost by others, as by the Turdus 
 inifjratorius. So again with "many thrushes, the feathers 
 .on the back are mottled before they are moulted for the 
 first time, and this character is retained for life by certain 
 eastern species. The young of many species of shrikes 
 (Lanius), of some woodpeckers and of an Indian pigeon 
 (Chalcopliaps indicus) are transversely striped on the 
 under surface; and certain allied species or whole genera 
 are similarly marked when adult. In some closely allied 
 and resplendent Indian cuckoos (Chrysococcyx) the mature 
 species' differ considerably from one another in color, but 
 the young cannot be distinguished. The young of an 
 Indian goose (Sarkidiornis melanonotus) closely resemble 
 in plumage an allied genus, Dendrocygna, when mature.* 
 
 * In regard to thrushes, shrikes and woodpeckers, see Mr. Blyth, 
 in Charlesworth's "Mag. of Nat. Hist.," vol. i, 1837, p. 304; also
 
 530 THE DESCENT OF MAN. 
 
 Similar facts will hereafter be given in regard to certain 
 herons. Young black grouse ( Tetrao tetrix) resemble the 
 young as well as the old of certain other species, for in- 
 stance, the red grouse or T. scoticus. Finally, as Mr. 
 Blyth, who has attended closely to this subject, has well 
 remarked, the natural affinities of many species are best 
 exhibited in their immature plumage; and as the true 
 affinities of all organic beings depend on their descent from 
 a common progenitor, this remark strongly confirms the 
 belief that the immature plumage approximately shows us 
 the former or ancestral condition of the species. 
 
 Although many young birds belonging to various famb 
 lies thus give us a glimpse of the plumage of their remote 
 progenitors, yet there are many other birds, both dull-, 
 colored and bright-colored, in which the young closely 
 resemble their parents. In such cases the young of tha 
 different species cannot resemble each other more closely 
 than do the parents; nor can they strikingly resemble 
 allied forms when adult. They give us but little insight 
 into the plumage of their progenitors, excepting in so far 
 that when the young and the old are colored in the same 
 general manner throughout a whole group of species, it is 
 probable that their progenitors were similarly colored. 
 
 We may now consider the classes of cases under which 
 the differences and resemblances between the plumage of 
 the young and the old, in both sexes or in one sex alone, 
 may be grouped. Rules of this kind were first enounced 
 by Ouvier; but with the progress of knowledge they require 
 some modification and amplification. This I have at- 
 tempted to do) as far as the extreme complexity of the 
 subject permits, from information derived from varioua 
 sources; but a full essay on this subject by some competent 
 ornithologist is much needed. In order to ascertain to 
 what extent each rule prevails I have tabulated the facts 
 given in four great works, namely, by Macgillivray on thd 
 birds of Britain, Audubon on those of North America, 
 Jerdon on those of India, and Gould on those of Australia. 
 
 foot-note to his translation of Cuvier's " Regne Animal," p. 159. I 
 give the case of Loxia on Mr. Blyth's information. On thrushes, see 
 also Audubon, "Ornith. Biography," vol. ii, p. 195. On Chryso. 
 coccyx and Chalcophaps, Blyth, as quoted in Jerdon's " Birds of 
 India," vol. iii, p. 485. On "Sarkidiornis, Blyth, in "Ibis," 1867, p, 
 175.
 
 BIRDS. 531 
 
 I may here premise, first, that the several cases or rules 
 graduate into each other; and secondly, that when the 
 young are said to resemble their parents it is not meant 
 that they are identically alike, for their colors are almost 
 always less vivid, and the feathers are softer and often of a 
 different shape. 
 
 RULES OB CLASSES OF CASES. 
 
 I. When the adult male is more beautiful or conspicuous 
 than the adult female, the young of both sexes in their 
 first plumage closely resemble the adult female, as with 
 the common fowl and peacock; or, as occasionally occurs, 
 they resemble her much more closely than they do the 
 adult male. 
 
 II. When the adult female is more conspicuous than 
 the adult male, as sometimes, though rarely, occurs, the 
 young of both sexes in their first plumage resemble the 
 adult male. 
 
 III. When the adult male resembles the adult female, 
 the young of both sexes have a peculiar first plumage of 
 their own, as with the robin. 
 
 IV. When the adult male resembles the adult female, 
 the young of both sexes in their first plumage resemble the 
 adults, as with the kingfisher, many parrots, crows, hedge- 
 warblers. 
 
 V. When the adult of both sexes have a distinct winter 
 and summer plumage, whether or not the male differs from 
 the female, the young resemble the adults of both sexes in 
 their winter dress, or much more rarely in their summer 
 dress, or they resemble the females alone. Or the young 
 may have an intermediate character; or again they may 
 differ greatly from the adults in both their seasonal 
 plumages. 
 
 VI. In some few cases the young in their first plumage 
 differ from each other according to sex; the young males 
 resembling more or less closely the adult males, and the 
 young females more or less closely the adult females. 
 
 CLASS I. In this class the young of both sexes more or 
 less closely resemble the adult female, while the adult male 
 differs from the adult female, often in the most conspicu- 
 ous manner. Innumerable instances in all orders could be
 
 532 THE DESCENT OF MAN. 
 
 given; it will suffice to call to mind the common pheasant, 
 duck and house-sparrow. The cases under this class gradu- 
 ate into others. Thus the two sexes when adult may differ 
 BO slightly, and the young so slightly from the adults, that 
 it is doubtful whether such cases ought to come under the 
 present, or under the third or fourth classes. So, again, 
 the young of the two sexes, instead of being quite alike, 
 may differ in a slight degree from each other, as in our 
 sixth class. These transitional cases, however, are few, 
 or at least are not strongly pronounced, in comparison with 
 those which come strictly under the present class. 
 
 The force of the present law is well shown in those 
 groups, in which, as a general rule, the two sexes and the 
 young are all alike; for when in these groups the male does 
 differ from the female, as with certain parrots, kingfishers, 
 pigeons, etc., the young of both sexes resemble the 
 adult female.* We see the same fact exhibited still 
 more clearly in certain anomalous cases; thus the male of 
 Heliotlirix auriculata (one of the humming-birds) differs 
 conspicuously from the female in having a splendid gorget 
 and fine ear-tufts, but the female is remarkable from 
 having a much longer tail than that of the male; now the 
 young of both sexes resemble (with the exception of the 
 breast being spotted with bronze) the adult female in all 
 other respects, including the length of her tail, so that the 
 tail of the male actually becomes shorter as he reaches 
 maturity, which is a most unusual circumstance, f Again, 
 the plumage of the male goosander (Mergus merganser) is 
 more conspicuously colored than that of the female, with 
 the scapular and secondary wing- feathers much longer; but 
 
 * See, for instance, Mr. Gould's account (" Hand-book to the Birds 
 of Australia/' vol. i, p. 133) of Cyanalcyon (one of the kingfishers), 
 in which, however, the young male, though resembling the adult 
 female, is less brilliantly colored. In some species of Dacelo the 
 males have blue tails, and the females brown ones; and Mr. R. B. 
 Sharpe informs me that the tail of the young male of D. gaiidichaudi 
 is at first brown. Mr. Gould has described (ibid, vol. ii, pp. 14, 20, 
 37) the sexes and the young of certain black cockatoos and of the 
 King Lory, with which the same rule prevails. Also Jerdon (" Birds 
 of India," vol. 5, p. 260) on the Palceornis rosa, in which the young 
 are more like the female than the male. See Audubon (" O'rnith. 
 Biograph.," vol. ii, p. 475) on the two sexes and the young of Co- 
 lumba passerina. 
 
 f I owe this information to Mr. Gould, who showed me the speci- 
 mens; see also his " Introduction to the Trochilidae," 1861, p. 120.
 
 BIRDS. 533 
 
 differently from what occurs, as far as I know in any other 
 bird, the crest of the adult male, though broader than that 
 of the female, is considerably shorter, being only a little 
 above an inch in length; the crest of the female being two 
 and a half inches long. Now the young of both sexes 
 entirely resemble the adult female, so that their crests are 
 actually of greater length, though narrower than in the 
 adult male.* 
 
 When the young and the females closely resemble each 
 other and both differ from the males, the most obvious con- 
 clusion is that the males alone have been modified. Even 
 in the anomalous cases of the Heliothrix and Mergus, it is 
 probable that originally both adult sexes were furnished 
 the one species with a much elongated tail and the other 
 with a much elongated crest these characters having since 
 been partially lost by the adult males from some unexplained 
 cause, and transmitted in their diminished state to their 
 male offspring alone, when arrived at the corresponding 
 age of maturity. The belief that in the present class the 
 male alona has been modified, as far as the differences 
 between the male and the female together with her young 
 are concerned, is strongly supported by some remarkable 
 facts recorded by Mr. Blyth,f with respect to closely allied 
 species which represent each other in distinct countries. 
 For with several of these representative species the adult 
 males have undergone a certain amount of change and can 
 be distinguished; the females and the young from the dis- 
 tinct countries being indistinguishable, and therefore 
 
 the case with certain 
 certain honey-suckers (Nee- 
 certain kingfishers (Tany- 
 siptera), Kalij pheasants (Gallophasis) and tree-partridges 
 (Arboricola). 
 
 In some analogous cases, namely, with birds having a 
 different summer and winter plumage, but with the two sexes 
 nearly alike, certain closely allied species can easily be dis- 
 tinguished in their summer or nuptial plumage, yet are 
 
 " * Macgillivray, " Hist. Brit. Birds," vol. v, pp. 207, 214 
 
 f See his admirable paper in the " Journal of the Asiatic Soc. of 
 Bengal," vol. xix, 1850, p. 223; see also Jerdon, " Birds of India," 
 vol. i, introduction, p. 29. In regard to Tanysiptera, Prof. Schlegel 
 told Mr. Blyth that he could distinguish several distinct races, solely 
 by comparing the adult males.
 
 534 THE DESCENT OF MAN. 
 
 indistinguishable in their winter as well as in their imma- 
 ture plumage. This is the case with some of the closely 
 allied Indian wag- tails or Motacillae. Mr. Swinhoe * 
 informs me that three species of Ardeola, a genus of 
 herons, which represent one another on separate conti- 
 nents, are " most strikingly different " when ornamented 
 with their summer plumes, but are hardly, if at all, dis- 
 tinguishable during the winter. The young also of these 
 three species in their immature plumage closely resemble 
 the adults in their winter dress. This case is all the 
 more interesting, because with two other species of Ardeola 
 both sexes retain, during the winter and summer, nearly 
 the same plumage as that possessed by the three first spe- 
 cies during the winter and in their immature state; and 
 this plumage, which is common to several distinct species 
 at different ages and seasons, probably shows us how the 
 progenitors of the genus were colored. In all these cases, 
 the nuptial plumage which we may assume was originally 
 acquired by the adult males during the breeding-season, 
 and transmitted to the adults of both sexes at the corre- 
 sponding season, has been modified, while the winter ?nd 
 immature plumages have been left unchanged. 
 
 The question naturally arises, how is it that in these 
 latter cases the winter plumage of both sexes, and in 
 the former cases the plumage of the adult females, as 
 well as the immature plumage of the young, have not been 
 at all affected? The species which represent each other in 
 distinct countries will almost always have been exposed to 
 somewhat different conditions, but we can hardly attribute 
 to this action the modification of the plumage in the males 
 alone, seeing that the females and the young, though simi- 
 larly exposed, have not been affected. Hardly any fact 
 shows us more clearly how subordinate in importance is 
 the direct action of the conditions of life, in comparison 
 with the accumulation through selection of indefinite vari- 
 ations, than the surprising difference between the sexes of 
 many birds; for both will have consumed the same food, 
 and have been exposed to the same climate. Nevertheless 
 we are not precluded from believing that in the course of 
 
 *See also Mr. Swinhoe, in "Ibis," July, 1863, p. 131; and a pre- 
 vious paper, with an extract from a note by Mr. Blyth, in " Ibis," 
 Jan. 1861, p. 24.
 
 BIRDS. 535 
 
 time new conditions may produce some direct effect either 
 on both sexes, or from their constitutional differences 
 chiefly on one sex. We see only that this is subordinate in 
 importance to the accumulated results of selection. Judg- 
 ing, however, from a wide-spread analogy, when a species 
 migrates into a new country (and this must precede the 
 formation of representative species), the changed condi- 
 tions to which they will almost always have been exposed 
 will cause them to undergo a certain amount of fluctuating 
 variability. In this case sexual selection, which depends 
 on an element liable to change the taste or admiration oi 
 the female will have had new shades of color or other dif- 
 ferences to act on and accumulate; and as sexual selection 
 is ihvays at work, it would (from what we know of the 
 results on domestic animals of man's unintentional selec- 
 tion) be surprising if animals inhabiting separate districts, 
 which can never cross and thus blend their newly acquired 
 characters, were not, after a sufficient lapse of time, differ- 
 ently modified. These remarks likewise apply to the 
 nuptial or summer plumage, whether confined to the males 
 or common to both sexes. 
 
 Although the females of the above closely allied or rep- 
 resentative species, together with their young, differ hardly 
 at all from one another, so that the males alone can be dis- 
 tinguished, yet the females of most species within the same 
 genus obviously differ from each other. The differences, 
 however, are rarely as great as between the males. We see 
 this clearly in the whole family of the Gallinacese ; the 
 females, for instance, of the common and Japan pheasant, 
 and especially of the gold and Amherst pheasant of the 
 silver pheasant and the wild fowl resemble one another 
 very closely in color, while the males differ to an extraor- 
 dinary degree. So it is with the females of most of the 
 Cotingidae, Fringillidse, and many other families. There 
 can indeed be no doubt that, as a general rule, the females 
 have been less modified than the males. Some few birds, 
 however, offer a singular and inexplicable exception; thus 
 the females of Paradisea apoda and P. papuana differ from 
 each other more than do their respective males;* the female 
 of the latter species having the under surface pure white, 
 while the female P. apoda is deep brown beneath. So, 
 
 * Wallace, " The Malay Archipelago," vol. ii, 1869, p. 394.
 
 536 THE DESCENT OF MAN. 
 
 again, as I hear from Prof. Newton, the males of two 
 species of Oxynotus (shrikes), which represent each other in 
 the Islands of Mauritius and Bourbon,* differ but little in 
 color, while the females differ much. In the Bourbon 
 species the female appears to have partially retained an 
 immature condition of plumage, for at first sight she 
 "might be taken for the young of the Mauritian species." 
 These differences may be compared with those inexplicable 
 ones which occur independently of man's selection in 
 certain sub-breeds of the game-fowl, in which the females 
 are very different, while the males can hardly be distin- 
 guished, f 
 
 As I account so largely by sexual selection for the differ- 
 ences between the males of allied species, how can the 
 differences between the females be accounted for in all 
 ordinary cases? We need not here consider the species 
 which belong to distinct genera; for with these, adaptation 
 to different habits of life, and other agencies, will have 
 come into play. In regard to the differences between the 
 females within the same genus it appears to me almost cer- 
 tain, after looking through various large groups, that the 
 chief agent has been the greater or less transference to the 
 female of the characters acquired by the males through 
 sexual selection. In the several British finches the two 
 sexes differ either very slightly or considerably; and if we 
 compare the females of the greenfinch, chaffinch, goldfinch, 
 bullfinch, crossbill, sparrow, etc., we shall see that they 
 differ from one another chiefly in the points in which they 
 partially resemble their respective males; and the colors of 
 the males may safely be attributed to sexual selection. 
 With many gallinaceous species the sexes differ to an 
 extreme degree, as with the peacock, pheasant and fowl, 
 while with other species there has been a partial or even 
 complete transference of character from the male to the 
 female. The females of the several species of Polyplectron 
 exhibit in a dim condition, and chiefly on the tail, the 
 splendid ocelli of their males. The female partridge differs 
 from the male only in the red mark on her breast being 
 smaller; and the female wild turkey only in her colors being 
 
 * These species are described with colored figures, by M. F- Pollen, 
 in " Ibis," 1866, p. 275. 
 f ' Variation of Animals, etc., under Domestication," vol. i, p. 251.
 
 BIRDS. 537 
 
 much duller. In the guinea-fowl the two sexes are indis- 
 tinguishable. There is no improbability in the plain, 
 though peculiarly spotted, plumage of this latter bird 
 having been acquired through sexual selection by the 
 males, and then transmitted to both sexes; for it is not 
 essentially different from the much more beautifully 
 spotted plumage, characteristic of the males alone of the 
 Tragopan pheasants. 
 
 It should be observed that in some instances the trans- 
 ference of characters from the male to the female has been 
 effected apparently at a remote period, the male having 
 subsequently undergone great changes without transferring 
 to the female any of his later gained characters. For in- 
 stance, the female and the young of the black grouse 
 (Tetrao tetrix] resemble pretty closely both sexes and the 
 young of the red grouse (T. scoticus); and we may conse- 
 quently infer that the black grouse is descended from some 
 ancient species, of which both sexes were colored in nearly 
 the same manner as the red grouse. As both sexes of this 
 latter species are more distinctly barred during the breed- 
 ing-season than at any other time, and as the male differs 
 slightly from the female in his more strongly pronounced 
 red and brown tints,* we may conclude that his plumage 
 has been influenced by sexual selection, at least to a certain 
 extent. If so, we may further infer that the nearly similar 
 plumage of the female black grouse was similarly produced 
 at some former period. But since this period the male 
 black grouse has acquired his fine black plumage with his 
 forked and outwardly curled tail-feathers; but of these char- 
 acters there has hardly been any transference to the female, 
 excepting that she shows in her tail a trace of the curved 
 fork. 
 
 We may therefore conclude that the females of distinct 
 though allied species have often had their plumage rendered 
 more or less different by the transference of various degrees- 
 of characters acquired by the males through sexual selec- 
 tion both during former and recent times. But it deserves 
 jespecial attention that brilliant colors have been transferred 
 much more rarely than other tints. For instance, the 
 male of the red-throated blue-breast (Cyanecula suecicd) 
 has a rich blue breast, including a sub-triangular red mark; 
 
 *Macgillivray, "Hist. British Birds." vol. i, pp. 173-174.
 
 538 THE DESCENT OF MAN. 
 
 now marks of nearly the same shape have been transferred 
 to the female, but the central space is fulvous instead of 
 red and is surrounded by mottled instead of blue feathers. 
 The Gallinaceae offer many analogous cases; for none of 
 the species, such as partridges, quails, guinea-fowl, etc., 
 in which the colors of the plumage have been largely trans- 
 ferred from the male to the female, are brilliantly colored. 
 This is well exemplified with the pheasants, in which the 
 male is generally so much more brilliant than the female; 
 but with the eared and cheer pheasants (Crossoptilon 
 auritum and Phasianus wctllicJiii) the sexes closely resem- 
 ble each other and their colors are dull. We may go so 
 far as to believe that if any part of the plumage in the 
 males of these two pheasants had been brilliantly colored it 
 would not have been transferred to the females. These facts 
 strongly support Mr. Wallace's view that with birds which 
 are exposed to much danger during incubation, the trans- 
 ference of bright colors from the male to the female has 
 been checked through natural selection. We must not, 
 however, forget that another explanation, before given, is 
 possible; namely, that the males which varied and became 
 bright, while they were young and inexperienced, would 
 have been exposed to much danger and would generally 
 have been destroyed; the older and more cautious males, on 
 the other hand, if they varied in a like manner, would not 
 only have been able to survive, but would have been 
 favored in their rivalry with other males. Now variations 
 occurring late in life tend to be transmitted exclusively to 
 the same sex, so that in this case extremely bright tints 
 would not have been transmitted to the females. On the 
 other hand, ornaments of a less conspicuous kind, such as 
 those possessed by the eared and cheer pheasants, would not 
 have been dangerous, and if they appeared during early 
 youth would generally have been transmitted to both 
 
 In addition to the effects of the partial transference of 
 characters from the males to the females some of the differ- 
 ences between the females of closely allied species may be 
 attributed to the direct or definite action of the conditions 
 of life.* With the males any such action would generally 
 
 * See, on this subject, chap, xxiii, in the " Variation of Animals 
 and Plants under Domestication."
 
 BIRDS. 539 
 
 have been masked by the brilliant colors gained through 
 sexual selection; but not so with the females. Each of the 
 endless diversities in plumage which we see in our domes- 
 ticated birds is, of course, the result of some definite cause; 
 and, under natural and more uniform conditions, some one 
 tint, assuming that it was in no way injurious, would almost 
 certainly sooner or later prevail. The free intercrossing of 
 the many individuals belonging to the same species would 
 ultimately tend to make any change of color thus induced 
 uniform in character. 
 
 No one doubts that both sexes of many birds have had 
 their 'colors adapted for the sake of protection; and it is 
 possible that the females alone of some species may have 
 been modified for this end. Although it would be a difficult, 
 perhaps an impossible, process, as shown in the last chapter, 
 to convert one form of transmission into another through 
 selection, there would not be the least difficulty in adapting 
 the colors of the female, independently of those of the male, 
 to surrounding objects, through the accumulation of varia- 
 tions which were from the first limited in their transmission 
 to the female sex. If the variations were not thus limited 
 the bright tints of the male would be deteriorated or de- 
 stroyed. Whether the females alone of many species have 
 been thus specially modified is at present very doubtful. 
 I wish I could follow Mr. Wallace to the full extent; 
 for the admission would remove some difficulties. Any 
 variations which were of no service to the female as a 
 protection would be at once obliterated, instead of being 
 lost simply by not being selected, or from free intercross- 
 ing, or from being eliminated when transferred to the male 
 and in any way injurious to him. Thus the plumage of the 
 female would be kept constant in character. It would also 
 be a relief if we could admit that the obscure tints of both 
 sexes of many birds had been acquired and preserved for the 
 sake of protection, for example, of the hedge-warbler or kitty- 
 wren (Accentor modularis and Troglodytes vulgaris), with 
 respect to which we have no sufficient evidence of the 
 'action 'of sexual selection. We ought, however, to be cau- 
 tious in concluding that colors which appear to us dull 
 are not attractive to the females of certain species; we 
 should bear in mind such cases as that of the common 
 house-sparrow, in which the male differs much from the 
 female, but does not exhibit any bright tints. No one
 
 540 TEE DESCENT OF MAN. 
 
 probably will dispute that many gallinaceous birds which: 
 live on the open ground have acquired their present 
 colors, at least in part, for the sake of protection. We 
 know how well they are thus concealed ; we know that 
 ptarmigans, while changing from their winter to their 
 summer plumage, both of which are protective, suffer 
 greatly from birds of prey. But can we believe that the 
 very slight differences in tints and markings between, for 
 instance, the female black- grouse and red-grouse serve as a 
 protection? Are partridges, as they are now colored, 
 better protected than if they had resembled quails? Do the 
 slight differences between the females of the common 
 pheasant, the Japan and gold pheasants, serve as a pro- 
 tection, or might not their plumages have been inter- 
 changed with impunity? From what Mr. Wallace hap 
 observed of the habits of certain gallinaceous birds in the 
 east, he thinks that such slight differences are beneficial. 
 For myself, I will only say that I am not convinced. 
 
 Formerly when I was inclined to lay much stress on pro- 
 tection as accounting for the duller colors of female birds, 
 it occurred to me that possibly both sexes and the young 
 might aboriginally have been equally bright colored ; but 
 that subsequently, the females from the danger incurred 
 during incubation, and the young from being inexperienced, 
 had been rendered dull as a protection. But this view is 
 not supported by any evidence, and is not probable; for 
 we thus in imagination expose during past times the 
 females and the young to danger, from which it has sub- 
 sequently been necessary to shield their modified descend- 
 ants. "Vye have, also, to reduce, through a gradual process 
 of selection, the females and the young to almost exactly 
 the same tints and markings, and to transmit them to the 
 corresponding sex and period of life. On the supposition 
 that the females and the young have partaken during each 
 stage of the process of modification of a tendency to be as 
 brightly colored as the males, it is also a somewhat strange 
 fact that the females have never been rendered dull colored 
 without the young participating in the same change; for 
 there are no instances, as far as I can discover, of species 
 with the females dull and the young bright colored. A 
 partial exception, however, is offered by the young of cer- 
 tain woodpeckers, for they have " the whole upper part of 
 the head tinged with red/' which &f terwayd, either
 
 BIRDS 541 
 
 into a mere circular red line in the adults of both sexes, or 
 quite disappears in the adult females.* 
 
 Finally, with respect to our present class of cases, the 
 most probable view appears to be that successive variations 
 in brightness or in other ornamental characters occurring 
 in the males at a rather late period of life have alone been 
 preserved; and that most or all of these variations, owing 
 to the late period of life at which they appeared, 
 have been from the first transmitted only to the adult male 
 offspring. Any variations in brightness occurring in the 
 females or in the young would have been of no service to 
 them, and would not have been selected; and moreover, if 
 dangerous would have been eliminated. Thus the females 
 and the young will either have been left unmodified, or 
 (as is much more common) will have been partially modi- 
 fied by receiving through transference from the males some 
 of his successive variations. Both sexes have perhaps been 
 directly acted on by the conditions of life to which they 
 have long been exposed; but the females from not being 
 otherwise much modified will best exhibit any such effects. 
 These changes and all others will have been kept uniform 
 by the free intercrossing of many individuals. In some 
 cases, especially with ground birds, the females and the 
 young may possibly have been modified, independently of 
 the males, for the sake of protection so as to have acquired 
 the same dull-colored plumage. 
 
 CLASS II. When the adult female is more conspicuous 
 than the adult male the young of both sexes in their first 
 plumage resemble the adult male. This class is exactly the 
 reverse of the last, for the females are here brighter colored 
 or more conspicuous than the males; and the young, as far 
 as they are known, resemble the adult males instead of the 
 adult females. But the difference between the sexes is 
 never nearly so great as with many birds in the first class, 
 and the cases are comparatively rare. Mr. Wallace, who 
 \first called attention to the singular relation which exists 
 between the less bright colors of the males and their per- 
 forming the duties of incubation, lays great stress on this 
 
 *Audubon, "Ornith. Biography," vol. i, p. 193. Macgillivray, 
 " Hist. Brit. Birds," voL iii, p. 85. See also the case before given of 
 Indopicus carlotta.
 
 542 THE DESCENT OF MAN. 
 
 point* as a crucial test that obscure colors have been ac- 
 ^uired for the sake of protection during the period of nest- 
 ing. A different view seems to me more probable. As 
 the cases are curious and not numerous I will briefly give 
 all that I have been able to find. 
 
 In one section of the genus Turnix, quail-like birds, the 
 female is invariably larger than the male ('being nearly 
 twice as large in one of the Australian species), and this is 
 an unusual circumstance with the Gallinacese. In most of 
 the species the female is more distinctly colored and 
 brighter than the male,f but in some few species the sexes 
 are alike. In Turmx taigoor of India the male " wants 
 the black on the throat and neck, and the whole tone of 
 the plumage is lighter and less pronounced than that of 
 the female." The female appears to be noisier, and is cer- 
 tainly much more pugnacious than the male; so that the 
 females and not the males are often kept by the natives for 
 fighting, like gamecocks. As male birds are exposed by 
 the English bird-catchers for a decoy near a trap, in order 
 to catch other males by exciting their rivalry, so the females 
 of this Turnix are employed in India. When thus ex- 
 posed the females soon begin their "loud, purring call, 
 which can be heard a long way off, and any females within 
 ear-shot run rapidly to the spot and commence fighting 
 with the caged bird." In this way from twelve to twenty 
 birds, all breeding-females, may be caught in the course of 
 a single day. The natives assert that the females after 
 laying their eggs associate in flocks, and leave the males to 
 sit on them. There is no reason to doubt the truth 
 of this assertion, which is supported by some observa- 
 tions made in China by Mr. Swinhoe.J Mr. Blyth 
 believes that the young of both sexes resemble the adult 
 male. 
 
 The females of the three species of painted snipes 
 (Rhynchaea, fig. 62) " are not only larger but much more 
 
 *" Westminster Review," July, 1867, and A. Murray, "Journal 
 of Travel," 1868, p. 83. 
 
 fFor the Australian species, see Gould's " Hand-book," etc., vol. 
 ii, pp. 178, 180, 186, 188. In the British Museum specimens of the 
 Australian Plain- wanderer (Pedionomus torquatus) may be seen, 
 showing similar sexual differences. 
 
 JJerdon, "Birds of India," vol. iii, p. 596. Mr. Svvinhoe, in 
 " Ibis," 1865, p. 542; 1866, pp. 131, 405.
 
 BIRDS 
 
 543 
 
 richly colored than the males."* With all other birds in 
 which the trachea differs in structure in the two sexes it is 
 more developed and complex in the male than in the 
 female; but/ in the Rliynclicea aitstraUs it is simple in the 
 male, while in the female it makes four distinct convolu- 
 
 Fig. 62. Rhynchaea capensis (from Brehm). 
 
 tions before entering the lungs, f The female, therefore, 
 of this species has acquired an eminently masculine char- 
 acter. Mr. Blyth ascertained, by examining many speci- 
 mens, that the trachea is not convoluted in either sex of 
 R. bengalensis, which species resembles R. australis so 
 closely that it can hardly be distinguished except by its 
 shorter toes. This fact is another striking instance of the 
 
 * Jerdon, "Birds of India," vol. iii, p. 677. 
 
 f Gould's " Hand-book to the Birds of Australia," vol. ii, p. 275.
 
 544: THE DESCENT OF MAN. 
 
 law that secondary sexual characters are often widely dif, 
 ferent in closely allied forms, though it is a very rare cir- 
 cumstance when such differences relate to the female sex. 
 The young of both sexes of R. bengalensis in their first 
 plumage are said to resemble the mature male.* There is 
 also reason to believe that the male undertakes the duty of 
 incubation, for Mr. Swinhoe f found the females before the 
 close of the summer associated in flocks, as occurs with the 
 [females of the Turnix. 
 
 The females of Phalaropus fulicarius and P. liyperloreus 
 are larger, and in their summer plumage " more gayly 
 attired than the males." But the difference in color between 
 the sexes is far from conspicuous. According to Prof. Steen- 
 strup, the male alone of P. fulicarius undertakes the duty of 
 incubation; this is likewise shown by the state of his 
 breast-feathers during the breeding-season. The female of 
 the dotterel plover (Eudromias morinellus) is larger than 
 the male, and has the red and black tints on the lower sur- 
 face, the white crescent on the breast and the stripes over 
 the eyes more strongly pronounced. The male also takes 
 at least a share in hatching the eggs; but the female like- 
 wise attends to the young. \ I have not been able to dis- 
 cover whether with these species the young resemble the 
 adult males more closely than the adult females; for the 
 comparison is somewhat difficult to make on account of the 
 double moult. 
 
 Turning now to the ostrich order; the male of the 
 common cassowary (Casuanus galeatus) would bethought 
 by any one to be the female, from his smaller size and from 
 the appendages and naked skin about his head being much 
 less brightly colored; and I am informed by Mr. Bartlett 
 that in the Zoological Gardens it is certainly the male alone 
 
 * " The Indian Field," Sept., 1858, p. 3. 
 f " Ibis," 1866, p. 298. 
 
 | For these several statements, see Mr. Gould's "Birds of Great 
 Britain." Prof. Newton informs me that he has long been convinced, 
 from his own observations and from those of others, that the males 
 of the above-named species take either the whole or a large share of 
 the duties of incubation, and that they "show much greater devo- 
 tion toward their young, when in danger, than do the females." So 
 it is, as he informs me, with Limosa litpponica and some few other 
 waders, in which the females are larger and have more strongly con- 
 trasted colors than the males.
 
 BIRDS. 546 
 
 who sits on the eggs and takes care of the young.* The 
 female is said by Mr. T. W. Wood f to exhibit during the 
 breeding- season a most pugnacious disposition ; and her 
 wattles then become enlarged and more brilliantly colored. 
 So again the female of one of the emus (Dromceus irroratus) 
 is considerably larger than the male, and she possesses a slight 
 top-knot, but is otherwise indistinguishable in plumage. 
 She appears, however, " to have greater power, when angry 
 or otherwise excited, of erecting, like a turkey-cock, the 
 feathers of her neck and breast. She is usually the more 
 courageous and pugilistic. She makes a deep, hollow, gut- 
 tural boom especially at night, sounding like a small gong. 
 The male has a slenderer frame and is more docile, with no 
 voice beyond a suppressed hiss when angry, or a croak." 
 He not only performs the whole duty of incubation, but 
 has to defend the young from their mother; " for as soon 
 as she catches sight of her progeny she becomes violently 
 agitated, and notwithstanding the resistance of the father 
 appears to use her utmost endeavors to destroy them. For 
 months afterward it is unsafe to put the parents together, 
 violent quarrels being the inevitable result, in which the 
 female generally comes oif conqueror/']; So that with this 
 emu we have a complete reversal not only of the parental 
 and incubating instincts, but of the usual moral qualities of 
 the two sexes; the females being savage, quarrelsome and 
 noisy, the males gentle and good. The case is very dif- 
 ferent with the African ostrich, for the male is somewhat 
 larger than the female and has finer plumes, with more 
 strongly contrasted colors; nevertheless he undertakes the 
 whole duty of incubation. 
 
 *The natives of Ceram (Wallace, "Malay Archipelago," vol. ii, 
 p. 1 50) assert that the male and female sit alternately on the eggs; 
 but this assertion, as Mr. Bartlett thinks, may be accounted for by 
 the female visiting the nest to lay her eggs. 
 
 t " The Student," April, 1870, p. 124. 
 
 J See. the excellent account of the habits of this bird under con- 
 finement, by Mr. A. W. Bennett, in " Land and Water." May, 1868, 
 p. 233. ' 
 
 Mr. Sclater, on the incubation of the Struthiones, " Proc. Zool. 
 Soc.," June 9, 1863. So it is with the Rhea darwinii: Capt. Mus- 
 ters says ("At Home with the Patagonians," 1871, p. 128), that the 
 male is larger, stronger and swifter than the female, and of slightly 
 darker colors; yet he takes sole charge of the eggs and of the young- 
 just as does the male of the common species of Rhea.
 
 546 THE DESCENT OF MAN. 
 
 I will specify the few other cases known to me, in which 
 the female is more conspicuously colored than the male, 
 although nothing is known about the manner of incuba- 
 tion. With the carrion-hawk of the Falkland Islands 
 (Milvago leucurus] I was much surprised to find by dissec- 
 tion that the individuals, which had all their tints strongly 
 pronounced, with the cere and legs orange-colored, were the 
 adult females; while those with duller plumage and gray 
 legs were the males or the young. In an Australian tree- 
 creeper (Climaderis erytlirops) the female differs from the 
 male in "being adorned with beautiful, radiated, rufous 
 markings on the throat, the male having this part quite 
 plain." Lastly, in an Australian night-jar "the female 
 always exceeds the male in size and in the brilliance of 
 her tints; the males, on the other hand, have two white 
 spots on the primaries more conspicuous than in the 
 female."* 
 
 We thus see that the cases in which female birds are 
 more conspicuously colored than the males, with the young 
 in their immature plumage resembling the adult males 
 instead of the adult females, as in the previous class, are 
 not numerous, though they are distributed in various 
 orders. The amount of difference, also, between the sexes 
 is incomparably less than that which frequently occurs in 
 the last class; so that the cause of the difference, whatever 
 it may have been, has here acted on the females either less 
 energetically or less persistently than on the males in the 
 last class. Mr. Wallace believes that the males have had 
 
 * For the Milvago, see "Zoology of the Voyage of the 'Beagle': 
 Birds," 1841, p. 16. For the Cliniacteris and night-jar (Eurostopo- 
 dus), see Gould's "Hand-book to the Birds of Australia," vol. i, pp. 
 602, 97. The New Zealand shieldrake (Tadorna variegata) offers a 
 quite anomalous case; the head of the female is pure white, and her 
 back is redder than that of the male; the head of tfhe male is of a 
 rich dark bronzed color, and his back is clothed with finely penciled 
 slate-colored feathers, so that altogether he may be considered as the 
 more beautiful of the two. He is larger and more pugnacious than 
 the female, and does not sit on the eggs. So that in all these respects 
 this species comes under our first class of cases; but Mr. Sclater 
 (" Proc. Zool. Soc.," 1866, p. 150) was much surprised to observe 
 that the young of both sexes, when about three months old, resem- 
 bled in their dark heads and necks the adult males, instead of the 
 adult females; so that it would appear in this case that the females 
 Lave been modified, while the males and the young have retained a 
 former state of plumage.
 
 BIRDS. 547 
 
 their colors rendered less conspicuous for the sake of pro- 
 tection during the period of incubation; but the difference 
 between the sexes in hardly any of the foregoing cases 
 appears sufficiently great for this view to be safely accepted. 
 In some of the cases the brighter tints of the female are 
 almost confined to the lower surface, and the males, if thus 
 colored, would not have been exposed to danger while 
 sitting on ttie eggs. It should also be borne in mind that 
 the males are not only in a slight degree less conspicuously 
 colored than the females, but are smaller and weaker. 
 They have, moreover, not only acquired the maternal 
 instinct of incubation, but are less pugnacious and 
 vociferous than the females, and in one instance have 
 simpler vonal organs. Thus, an almost complete transposi- 
 tion of thn instincts, habits, disposition, color, size, and of 
 some points of structure, has been effected between the two 
 
 Now, if we might assume that the males in the present 
 class have lost some of that ardor which is usual to their 
 sex, so that they no longer search eagerly for the females; 
 or, if we might assume that the females have become much 
 more numerous than the males and in the case of one 
 Indian Turnix the females are said to be " much more 
 commonly met with than the males " * then it is not 
 improbable that the females would have been led to court 
 the males, instead of being courted by them. This indeed 
 is the case to a certain extent with some birds, as we have 
 seen with the peahen, wild turkey, and certain kinds of 
 grouse. Taking as our guide the habits of most male 
 birds, the greater size and strength, as well as the extraor- 
 dinary pugnacity of the females of the Turnix and emu, 
 must mean that they endeavor to drive away rival females 
 in order to gain possession of the male; and on this view 
 all the facts become clear ; for the males would probably 
 be most charmed or excited by the females which were tho 
 most attractive to them by their bright colors, other orna- 
 ments, or_ vocal powers. Sexual selection would then do 
 its 'work, steadily adding to the attractions of the females ; 
 the males and the young being left not at all, or but little, 
 modified. 
 
 CLASS III. WJien the adult male resembles the adult 
 
 * Jerdon, "Birds of India," vol. Ui, p. 598.
 
 548 THE DESCENT OF MAN. 
 
 .female, the young of both sexes have a peculiar first plumage 
 of their own. In this class the sexes when adult resemble 
 each other and differ from the young. This occurs with 
 many birds of many kinds. The male robin can hardly be 
 distinguished from the female, but the young are widely 
 different, with their mottled dusky-olive and brown plum- 
 age. The male and female of the splendid scarlet 
 ibis are alike, while the young are brown; and the scarlet 
 color, though common to both sexes, is apparently a sexual 
 character, for it is not well developed in either sex under 
 confinement ; and a loss of color often occurs with brill- 
 iant males when they are confined. With many species of 
 herons the young differ greatly from the adults; and the 
 summer plumage of the latter, though common to both 
 sexes, clearly has a nuptial character. Young swans are 
 slate-colored, while the mature birds are pure white; but it 
 would be superfluous to give additional instances. These 
 differences between the young and the old apparently 
 depend, as in the last two classes, on the young having 
 retained a former or ancient state of plumage, while the old 
 of both sexes have acquired a new one. When the adults 
 are bright colored, we may conclude from the remarks just 
 made in relation to the scarlet ibis and to many herons, and 
 from the analogy of the species in the first class, that such 
 colors have been acquired through sexual selection by the 
 nearly mature males ; but that, differently from what 
 occurs in the first two classes, the transmission, though lim- 
 ited to the same age, has not been limited to the same sex. 
 Consequently, the sexes when mature resemble each other 
 and differ from the young. 
 
 CLASS IV. WJien the adult male resembles the adult 
 female, the young of both sexes in their first plumage resem- 
 ble the adults. In this class the young and the adults of 
 both sexes, whether tmlliantly or obscurely colored, resem- 
 ble each other. Such cases are, I think, more common 
 than those in the last class. We have in England instances 
 in the kingfisher, some woodpeckers, the jay, magpie, 
 crow, and many small dull-colored birds, such as the 
 hedge-warbler or kitty-wren. - But the similarity in plum- 
 age between the young and the old is never complete, and 
 graduates away into dissimilarity. Thus the young of 
 some members of the kingfisher family are not only less
 
 BIRDS. 549 
 
 vividly colored than the adults, but many of the feathers 
 on the lower surface are edged with brown* a vestige 
 probably of a former state of the plumage. Frequently in 
 the same group of birds, even within the same genus 
 for instance, in the Australian genus of paroquets 
 (Platycercus), the young of some species closely resemble, 
 while the young of other species differ consider- 
 ably from, their parents of both sexes, which are alike, f 
 Both sexes and the young of the common -jay are closely 
 similar; but in the Canada jay (Perisoreus canadensis) the 
 young differ so much from their parents that they were 
 formerly described as distinct species. J 
 
 I may remark before proceeding that, under the present 
 and next two classes of cases, the facts are so complex and 
 the conclusions so doubtful that any one who feels no 
 especial interest in the subject had better pass them over. 
 
 The brilliant or conspicuous colors which characterize many birds 
 in the present class can rarely or never be of service to them as & 
 protection; so that they have probably been gained by the males 
 through sexual selection and then transferred to the females and 
 the young. It is, however, possible that the males may have selected 
 the more attractive females; and if these transmitted their characters 
 to their offspring of both sexes the same results would follow as 
 from the selection of the more attractive males by the females. But 
 there is evidence that this contingency has rarely, if ever, occurred 
 in any of those groups of birds in which the sexes are generally 
 alike; for, if even a few of the successive variations had failed to be 
 transmitted to both sexes, the females would have slightly exceeded 
 the males in beauty. Exactly the reverse occurs under nature; for, 
 in almost every large group in which the sexes generally resemble 
 each other, the males of some few species are in a slight degree more 
 brightly colored than the females. It is again possible that the ; 
 females may have selected the more beautiful males, these males 
 having reciprocally selected the more beautiful females; but it is ** 
 doubtful whether this double process of selection would be likely to 
 occur, owing to the greater eagerness of one sex than the other, and 
 whether it would be more efficient than selection on one side alone. 
 It is, therefore, the most probable view that sexual selection has 
 acted, in the present class, as far as ornamental characters are con- 
 cerned, in accordance with the general rule throughout the animal 
 kingdom, that is, on the males; and that these have transmitted their 
 
 *Jerdon, "Birds of India," vol. i, pp. 222, 228. Gould's "Hand- 
 book to the Birds of Australia," vol. i, pp. 124, 130. 
 f Gould, ibid, vol. ii, pp. 37, 46, 56. 
 J Audubon, " Ornith. Biography," vol. ii, p. 55.
 
 550 THE DESCENT OF MAN. 
 
 gradually acquired colors, either equally or almost equally, to thei* 
 offspring of both sexes. 
 
 Another point is more doubtful, namely, whether the successive 
 variations first appeared in the males after they had become nearly 
 mature or while quite young. In either case sexual selection must 
 have acted on the male when he had to compete with rivals for the 
 possession of the female; and in both cases the characters thus 
 acquired have been transmitted to both sexes and all ages But 
 these characters, if acquired by the males when adult, may have been 
 transmitted at first to the adults alone, and at some subsequent period 
 transferred to the young. For it is known that when the law of 
 inheritance at corresponding ages fails the offspring often inherit 
 characters at an earlier age th'an that at which they first appeared 
 in their parents.* Cases apparently of this kind have been observed 
 with birds in a state of nature. For instance, Mr. Blyth has seen 
 specimens of Lanius rufus and of Colymbus glacialis which had 
 assumed while young, in a quite anomalous manner, the adult 
 plumage of their parents, f Again, the young of the common swan 
 (Cygnus olor) do not cast off their dark, feathers and become white 
 until eighteen months or two years old; but Dr. F. Forel has 
 described the case of three vigorous young birds, out of a brood of 
 four, which were born pure white. These young birds were not 
 albinos, as shown by the color of their beaks and legs, which nearly 
 resembled the same parts in the adults.:): 
 
 It may be worth while to illustrate the above three modes by 
 which, in the present class, the two sexes and the young may have 
 come to resemble each other, by the curious case of the genus 
 Passer.g In the house-sparrow (P. domesticus) the male differs 
 much from the female and from the young. The young and the 
 females are alike, and resemble to a large extent both sexes and the 
 young of the sparrow of Palestine (P. bracJiydactyliis), as well as of 
 some allied species. We may therefore assume that the female and 
 young of the house-sparrow approximately show us the plumage of 
 the progenitor of the genus. Now with the tree-sparrow (P. mon- 
 ianus) both sexes and the young closely resemble the male of the 
 house-sparrow; so that they have all been modified in the same 
 manner, and all depart from the typical coloring of their early pro- 
 genitors. This may have been effected by a male ancestor of the tree- 
 sparrow having varied, firstly, when nearly mature; or, secondly, 
 while quite young, and by having in either case transmitted his 
 modified plumage to the females and the young; or, thirdly, he may 
 have varied when adult and transmitted his plumage to both adult 
 exes, and, owing to the failure of the law of inheritance at corre- 
 sponding ages, at some subsequent period to his young. 
 
 It is impossible to decide which of these three modes has generally 
 
 " Variation of Animals and Plants under Domestication," vol. H, p. 79. 
 
 t Charleflworth's " Mag. of Nat. Hist.," vol. 1, 1837, pp. 305, 806. 
 
 J" Bulletin de la Soc. Vaudolse des Sc. Nat.," vol. x, 1869, p. 132. The 
 Toun* of the Polish swan, Cygnus wimvtabilis of Yarrell, are always white; 
 but tola species, as Mr. Sclater informs me, is believed to be nothing more than 
 a rariety of the domestic swan (C'ygnvs olor). 
 
 1 1 am Indebted to Mr. Blyth for information in regard to this genus. The 
 sparrow of Palestine belongs to the sub-genus Petronla.
 
 BIRDS. 551 
 
 prevailed throughout the present class of cases. That the males 
 varied while young and transmitted their variations to their offspring 
 of both sexes is the most probable. I may here add that I have, 
 with little success, endeavored, by consulting various works, to 
 decide how far the period of variation in birds has generally deter- 
 mined the transmission of characters to one sex or to both. The two 
 rules, often referred to (namely, that variations occurring late in life 
 are transmitted to one and the same sex, while those which occur 
 early in life are transmitted to both sexes), apparently hold good in 
 the first,* second, and fourth classes of cases; but they fail in the 
 third, often in the fifth, f and in the sixth small class. They apply, 
 however, as far as I can judge, to a considerable majority of the 
 species; and we must not forget the striking generalization by Dr. 
 W. Marshall with respect to the protuberances on the heads of 
 birds. Whether or not the two rules generally hold good, we may 
 conclude from the facts given in the eighth chapter that the period 
 of variation is one important element in determining the form of 
 transmission. 
 
 With birds it is difficult to decide by what standard we ought to 
 judge of the earliness or lateness of the period of variation, whether 
 by the age in reference to the duration of life, or to the power of 
 reproduction, or to the number of moults through which the species 
 passes. The moulting of birds, even within the same family, some 
 times differs much without any assignable cause. Some birds moult 
 so early that nearly all the body-feathers are cast off before the first 
 wing- feathers are fully grown; and we cannot believe that this was 
 the primordial state of things. When the period of moulting has 
 been accelerated the age at which the colors of the adult plumage 
 are Srst developed will falsely appear to us to be earlier than it 
 really is. This may be illustrated by the practice followed by some 
 bird-fanciers, who pull out a few feathers from the breast of nestling 
 bullfinches, and from the head or neck of young Gold pheasants, in 
 order to ascertain their sex; for in the males, these feathers are 
 immediately replaced by colored ones4 The actual duration of life 
 is known in but few birds, so that we can hardly judge by this 
 standard. And with reference to the period at which the power of 
 reproduction is gained, it is a remarkable fact that various birds 
 occasionally breed while retaining their immature plumage. 
 
 * For instance, the males of Tanagra (estiva and Frinqitta cyanea require 
 three years, the male of Fnngilla ciris four years, to complete their beautful 
 plumage, (See Audubon, " Ornith. Biography," vol. i, pp. 233, 280, 378). The 
 Harlequin duck takes three years (ibid, vol. iii, p. 614). The male of the Gold 
 pheasant, as I heav from Mr. Jenner Weir, can be distinguished from the 
 female when about three nwnths old, but he does not acquire his full splendor 
 until the end of September in the following year. 
 
 t Thus the Ibis tantalus and Grus americamis take four years, the Flamingo 
 several years, and the Ardea ludovicana two years, before they acquire their 
 perfect plumage. See Audubon, ibid, vol. 5, p. 221; vol. iii, pp. 133, 139. 211. 
 
 $Mr. Blyth, In Charlesworth's "Mag. of Nat. Hist.," vol. 1, 1837, p. 300. 
 Mr. Bartlett has informed me in regard to Gold pheasants. 
 
 I have noticed the following cases in Audubon's " Ornith. Biography:" 
 The redstart of America (ifascapica rttticiUd), vol. i, p. 203. The Ibis tantahts 
 takes four years to come to full maturity, but sometimes breeds in the second 
 year (vol. iii, p. 133). The Grus amerlcanus takes the same time, but breeds be- 
 fore acquiring its full plumage (vol. iii, p. 211). The adults of Arclea caarulw
 
 552 THE DESCENT OF MAN. 
 
 The fact of birds breeding in their immature plumage seems 
 opposed to the belief that sexual selection has played as important a 
 part, as I believe it has, in giving ornamental colors, plumes, etc., to 
 the males, and, by means of equal transmission, to the females of 
 many species. The objection would be a valid one, if the younger 
 and less ornamented males were as successful in winning females and 
 propagating their kind, as the older and more beautiful males. But 
 we have no reason to suppose that this is the case. Audubon 
 speaks of the breeding of the immature males of Jbis tantalus as a 
 rare event, as does Mr. Swinhoe, in regard to the immature males of 
 Oriolus.* If the young of any species in their immature plumage 
 were more successful in winning partners than the adults, the adult 
 plumage would probably soon be lost, as the males would prevail 
 which retained their immature dress for the longest period, and thus 
 the character of the species would ultimately be modified. -f If, on 
 the other hand, the young never succeeded in obtaining a female, 
 the habit of early reproduction would perhaps be sooner or later 
 eliminated, from being superfluous and entailing waste of power. 
 
 The plumage of certain birds goes on increasing in beauty during 
 many years after they are fully mature; this is the case with the 
 train of the peacock, with some of the birds of paradise, and with 
 the crests and plumes of certain herons, for instance, the Ardea 
 ludovicana.\ But it is doubtful whether the continued development 
 of such feathers is the result of the selection of successive beneficial 
 variations (though this is the most probable view with birds of para- 
 dise) or merely of continuous growth. Most fishes continue increas- 
 ing in size, as long as they are in good health and have plenty of 
 food; and a somewhat similar law may prevail with the plumes of 
 birds. 
 
 CLASS V. When the adults of both sexes have a distinct winter 
 and summer plumage, whether or not the male differs from the 
 female, the young resemble the adults of both sexes in their winter 
 dress, or much more rarely in their nummer dress, or they resemble 
 
 are blue and the young 1 white; and white, mottled, and mature blue birds 
 may all be seen breeding together (vol. iv, p. 58); but Mr. Blyth Informs me 
 that certain herons apparently are dimorphic, for white and colored individ- 
 uals of the same age may be observed. The Harlequin duck (Ana* hiotrioidca, 
 Linn.) takes three years to acquire its full plumage, though many birds breed 
 in the second year (vol. iii, p. 614). The white-headed eagle (Falco leucocephalus), 
 vol. iii, p. 210, is likewise known to breed in its immature state. Some species 
 of Oriolus (according to Mr. Blyth and Air. Swinhoe, in " Ibis," July, 1863, p. 
 88) likewise breed before they attain their full plumage. 
 
 * See the last foot-note. 
 
 t Other animals, belonging to quite distinct classes, are either habitually 
 or occasionally capable of breeding before they have fully acquired their 
 adult characters. This is the case with the young males of the salmon. 
 Several amphibians have been known to breed while retaining their larval 
 structure. Fritz Muller has shown (" Facts and Arguments for Darwin," 
 Eng. trans., 1869, p. 79) that the males of .several amphipod crustaceans become 
 sexually mature while young; and I infer that this is a case of premature 
 breeding, because they have not as yet acquired their fully developed claspers. 
 All such facts are highly interesting, as bearing on one means by which species 
 may undergo great modifications or character. 
 
 1 Jerdon, " Birds of India," vol. iii, p. 507, on the peacock. Dr. Marshall 
 thinks that the older and more brilliant niMles of birels of paradise have an 
 advantage over the younger males; see " Archives Neerlandalses," torn, vi, 
 1871. On Ardea, Audubon. ibid, vol. iii, p. 139.
 
 BIEDS. 553 
 
 the females alone. Or the young may have an intermediate 
 character ; or, again, they may differ greatly from the adults in 
 both their seasonal plumages. The cases in this class are singularly 
 complex; nor is this surprising, as they depend on inheritance, 
 limited in a greater or less degree in three different ways, namely, 
 by sex, age, and the season of the year. In some cases the 
 individuals of the same species pass through at least five distinct 
 states of plumage. With the species in which the male differs 
 from the female during the summer season alone, or, which is rarer, 
 during both seasons,* the young generally resemble the females 
 as with the so-called goldfinch of North America, and apparently 
 with the splendid Maluri of Australia.! With those species, the 
 eexes of which are alike during both the summer and winter, the 
 young may resemble the adults, firstly, in their winter dress ; sec- 
 ondly, and this is of much rarer occurrence, in their summer dress ; 
 thirdly, they may be intermediate between these two states ; and, 
 fourthly, they may differ greatly from the adults at all seasons. We 
 have an instance of the first of these four cases in one of the egrets 
 of India (Buphus coi'omandus), in which the young and the adults of 
 both sexes are white during the winter, the adults becoming golden- 
 buff during the summer. With the gaper (Anastomus oscitans) of 
 India we have a similar case, but the colors are reversed ; for the 
 young and the adults of both sexes are gray and black during the 
 winter, the adults becoming 1 white during the summer. $ As an 
 instance of the second case, the young of the razor-bill (Alca torda, 
 Linn.), in an early state of plumage, are colored like the adults dur- 
 ing the summer; and the young of the white-crowned sparrow of 
 North America (Fringilla leucophrys), as soon as fledged, have elegant 
 white stripes on their heads, which are lost by the young and the old 
 during the winter. With respect to the third case, namely, that of 
 the young having an intermediate character between the summer 
 and winter adult plumages, Yarrell || insists that this occurs with 
 many waders. Lastly, in regard to the young differing greatly from 
 both sexes in tlieir adult summer and winter plumages, this occurs 
 with some hei 3ns and egrets of North America and India the 
 young alone being white. 
 
 I will make only a few remarks on these complicated cases. When 
 the young resemble the females in their summer dress, or the adults 
 of both sexes in their winter dress, the cases differ from those given 
 under Classes I and III only in the characters originally acquired 
 
 * For illustrative cases see vol. iv, of Macgillivray's " Hist. Brit. Birds ;" 
 on Tringa, etc., pp. 229, 271; on the Machetes, p. 172; on the Charadrius hiati- 
 cula, p. 118; on the Charadrius pluvialis, p. 94. 
 
 t For the goldfinch of North America, Fringilla tristis, Linn., see Audubon, 
 "Ornith. Biography," vol. i, p. 172. For the Maluri, Gould's " Hand-book to 
 the Birds of Australia," vol. i, p. 318. 
 
 $ 1 am indebted to Mr. Blyth for information as to the Buphus; see also 
 Jerdon, " Birds of India," vol. iii, p. 749. On the Anastomus, see Blyth, ia 
 " Ibis," 1867. p. 173. 
 
 On the Alca, see Macgillivray, " Hist. Brit. Birds," vol. v, p, 347. On the 
 Fringilla leitcophryc, Audubon, Ibid, vol. ii, p. 89. I shall have hereafter to 
 refer to the young of certain herons and egrets being white. 
 
 II History of British Birds," vol. i, 1839, p. 159.
 
 554 THE DESCENT OF MAN. 
 
 by the males during the breeding-season having been limited in then 
 transmission to the corresponding season. When the adults have a 
 distinct summer and winter plumage, ant the young differ from both, 
 the case is more difficult to understand. We may admit as probable 
 that the young have retained an ancient state of plumage; we cau 
 account by sexual selection for the summer or nuptial plumage of the 
 adults, but how are we to account for their distinct winter plumage t 
 If we could admit that this plumage serves in all cases as a protec- 
 tion, its acquirement would be a simple affair; but there seems no 
 good reason for this admission. It may be suggested that the 
 widely different conditions of life during the winter and summer 
 have acted in a direct manner on the plumage ; this may have had 
 some effect, but I have not much confidence in so great a difference 
 as we sometimes see between the two plumages having been thus 
 caused. A more probable explanation is, that an ancient style of 
 plumage, partially modified through the transference of some char- 
 acters from the summer plumage, has been retained by the adults 
 during the winter. Finally, all the cases in our present class appa- 
 rently depend on characters acquired by the adult males having 
 been variously limited in their transmission according to age, season, 
 and sex; but it would not be worth while to attempt to follow out 
 these complex relations. 
 
 CLASS VI. The young in their first plumage differ from each other 
 according to sex; the young males resembling more or less closely the 
 adult males, and the young females more or less closely the adult 
 females. The cases in the present class, though occurring in various 
 groups, are not numerous; yet it seems the most natural thing that 
 the young should at first somewhat resemble the adults of the same 
 sex, and gradually become more and more like them. The adult 
 male blackcap (Sylvia atricapitta) has a black head, that of the 
 female being reddish-brown; and I am informed by Mr. Blyth, that 
 the young of both sexes can be distinguished by this character even 
 as nestlings. In the family of thrushes an unusual number of simi- 
 lar cases have been noticed ; thus, the male blackbird (2\irdus 
 merula) can be distinguished in the nest from the female. The two 
 sexes of the mocking- bird (Turdus polyglottus, Linn.) differ very little 
 from each other, yet the males can easily be distinguished at a very 
 early age from the females by showing more pure white.* The 
 males of a forest-thrush and of a rock-thrush (Orocctes erythrogastra 
 and Petrocincla cyanea) have much of their plumage of a fine blue, 
 while the females are brown; and the nestling males of both species 
 have their main wing and tail feathers edged with blue, while those 
 of the female are edged with brown. f In the young blackbird the 
 wing-feathers assume their mature character and become black after 
 the others; on the other hand, in the two species just named the 
 wing-feathers become blue before the others. The most probable 
 view with reference to the cases in the present class is that the males, 
 
 * Audubon " Ornith. Biography," vol. i, p. 113. 
 
 tMr. C. A. Wright, in "Ibis," vol. vi, 1864, p. 65. Jerdon, "Birds of 
 India," vol. 1, p. 515. See also on the blackbird, Blyth, in Charlesworth'a 
 " Mag. of Nat. History," vol. i. 1837 o. 113.
 
 BIRDS. 555 
 
 differently from what occurs in Class I, have transmitted their colors 
 to their male offspring at an earlier age than that at which they were 
 first acquired; for, if the males had varied while quite young, their 
 characters would probably have been transmitted to both sexes.* 
 
 In A'ithurus polytmus, a humming-bird, the male is splendidly 
 colored black and green, and two of the tail-feathers are immensely 
 lengthened; the female has an ordinary tail and inconspicuous 
 'colors; now the young males, instead of resembling the adult 
 female, in accordance with the common rule, begin from the first to 
 assume the colors proper to their sex, and their tail-feathers soon 
 become elongated. I owe this information to Mr. Gould, who has 
 given me the following more striking and as yet unpublished case. 
 Two humming-birds belonging to the genus Eustephanus, both 
 beautifully colored, inhabit the small island of Juan Fernandez, and 
 have always been ranked as specifically distinct. But it has lately 
 been ascertained that the one which is of a rich chestnut-brown 
 color with a golden-red head, is the male, while the other, which is 
 elegantly variegated with green and white, with a metallic green 
 head, is the female. Now the young from the first somewhat resem- 
 ble the adults of the corresponding sex, the resemblance gradually 
 becoming more and more complete. 
 
 In considering this last case, if as before we take the plumage of 
 the young as our guide, it would appear that both sexes have been 
 rendered beautiful independently; and not that one sex has partially 
 transferred its beauty to the other. The male apparently has 
 acquired his bright colors through sexual selection in the same 
 manner as, for instance, the peacock or pheasant in our first class of 
 cases; and the female in the same manner as the female Rhynchsea 
 or Turnix in our second class of cases. But there is much difficulty 
 in understanding how this could have been effected at the same time 
 with the two sexes of the same species. Mr. Salvin states, as we 
 have seen in the eighth chapter, that with certain humming-birds 
 the males greatly exceed the females in number, while with other 
 species inhabiting the same country the females greatly exceed the 
 males. If, then, we might assume that during some former length- 
 ened period the males of the Juan Fernandez species had greatly 
 exceeded the females in number, but that during another lengthened 
 period the females had far exceeded the males, we could understand 
 how the males at one time, and the females at another, might have 
 been rendered beautiful by the selection of the brighter-colored 
 individuals of either sex; both sexes transmitting their characters to 
 their young at a rather earlier age than usual. Whether this is the 
 true explanation I will not pretend to say; but the case is too remark- 
 able to be passed over without notice. 
 
 * The following additional cases may be mentioned: the young males of 
 
 * a (Audubon, 
 ngs of a blue 
 
 Tanagra ttibra can be distinguished from the young females (Audubon 
 " Ornith. Biography," vol. iv, p. 892), and so it is within the nestlings of a blut 
 nuthatch, Dendrophila frontalis, of India (Jerdon, " Birds of India," vol. i, p. 
 
 889). Mr. Blyth also informs me that the sexes of the stonechat, Saxicola rubi- 
 cola, are distinguishable at a very early age. Mr. Salvin gives (" Proc. Zoolog. 
 Soc.," 1870, p. 206), the case of a humming-bird, like the following one of 
 Eustephanus.
 
 556 TEE DESCENT OF MAN. 
 
 We have now seen in all six classes that an intimate rela- 
 tion exists between the plumage of the young and the 
 adults, either of one sex or both. These relations ars 
 fairly well explained on the principle that one sex thie, 
 being in the great majority of cases the male first acquired 
 through variation and sexual selection bright colors or 
 other ornaments and transmitted them in various ways in 
 accordance with the recognized laws of inheritance. Why 
 variations have occurred at different periods of life, even 
 sometimes with species of the same group, we do not know, 
 but with respect to the form of transmission one important 
 determining cause seems to be the age at which the varia- 
 tions first appear. 
 
 From the principle of inheritance at corresponding ages 
 and from any variations in color which occurred in the 
 males at an early age not being then selected on the con- 
 trary being often eliminated as dangerous while similar 
 variations occurring at or near the period of reproduction 
 have been preserved, it follows that the plumage of the 
 young will often have been left unmodified, or but little 
 modified. We thus get some insight into the coloring of 
 the progenitors of our existing species. In a vast number 
 of species in five out of our six classes of cases the adults of 
 one sex or of both are bright colored, at least during the 
 breeding-season, while the young are invariably less brightly 
 colored than the adults, or are quite dull colored; for no 
 instance is known, as far as I can discover, of the young of 
 dull-colored species displaying bright colors, or of the young 
 of bright-colored species being more brilliant than their 
 parents. In the fourth class, however, in which the young 
 and the old resemble each other, there are many species 
 (though by no means all), of which the young are bright 
 colored, and, as these form old groups, we may infer that 
 their early progenitors were likewise bright. With this 
 exception, if we look to the birds of the world, it appears 
 that their beauty has been much increased since that 
 period, of which their immature plumage gives us a partial 
 record. 
 
 On the Color of the Plumage in Relation to Protection. 
 It will have been seen that I cannot follow Mr. Wallace in 
 the belief that dull colors, when confined to the females, 
 have been in most cases specially gained for the sake of
 
 BIRDS. 557 
 
 protection. There can, however, be no doubt, as formerly 
 remarked, that both sexes of many birds have had their 
 colors modified so as to escape the notice of their enemies; 
 or in some instances, so as to approach their prey unobserved, 
 just as owls have had their plumage rendered soft, that 
 their flight may not be overheard. Mr. Wallace remarks * 
 that " it is only in the tropics, among forests which never 
 lose their foliage, that we find whole groups of birds whose 
 chief color is green." It will be admitted by every one 
 who has ever tried how difficult it is to distinguish parrots 
 in a leaf -covered tree. Nevertheless^, we must remember 
 that many parrots are ornamented with crimson, blue and 
 orange tints, which can hardly be protective. Woodpeckers 
 are eminently arboreal, but besides green species there are 
 many black and black-and-white kinds all the species 
 being apparently exposed to nearly the same dangers. It 
 is therefore probable that with tree-haunting birds strongly 
 
 renounced colors have been acquired through sexual selec- 
 ou, but that a green tint has been acquired oftener than 
 any other from the additional advantage of protection. 
 
 In regard to birds which live on the ground, every one 
 admits that they are colored so as to imitate the surround- 
 ing surface. How difficult it is to see a partridge, snipe, 
 woodcock, certain plovers, larks and night-jars when 
 crouched on ground. Animals inhabiting deserts offer the 
 most striking cases, for the bare surface affords no conceal- 
 ment, and nearly all the smaller quadrupeds, reptiles and 
 birds depend for safety on their colors. Mr. Tristram has 
 remarked in regard to the inhabitants of the Sahara, that 
 all are protected by their " isabelline or sand color."f 
 Calling to my recollection the desert-birds of South 
 America, as well as most of the ground-birds of Great 
 Britain, it appeared to me that both sexes in such cases 
 are generally colored nearly alike. Accordingly, I applied 
 to Mr. Tristram with respect to the birds of the Sahara, 
 and he has kindly given me the following information: 
 There are twenty-six species belonging to fifteen genera, 
 - which" manifestly have their plumage colored in a protect- 
 
 * " Westminster Review," July, 1867, p. 5. 
 
 f " Ibis," 1859, vol. i, p. 429, et seg. Dr. Rohlfs, However, re- 
 marks to me in a letter that, according to his experience of th* 
 Sahara, this statement is too strong.
 
 558 THE DESCENT OF MAN. 
 
 ive manner; and this coloring is all the more striking, aa 
 with most of these birds it differs from that of their con- 
 geners. Both sexes of thirteen out of the twenty-six 
 species are colored in the same manner; but these belong 
 to genera in which this rule commonly prevails, so that 
 tfhey tell us nothing about the protective colors being the 
 same in both sexes of desert-birds. Of the other thirteen 
 species tbree belong to genera in which the sexes usually 
 differ from each other, yet here they have the sexes alike. 
 In the remaining ten species the male differs from the 
 female; but the difference is confined chiefly to the under 
 surface of the plumage, which is concealed when the bird 
 crouches on the ground; the head and back being of the 
 same sand-colored hue in the two sexes. So that in these 
 ten species the upper surfaces of both sexes have been acted 
 on and rendered alike through natural selection for the 
 sake of protection; while the lower surfaces of the males 
 alone have been diversified through sexual selection for the 
 sake of ornament. Here, as both sexes are equally well 
 protected, we clearly see that the females have not been 
 prevented by natural selection from inheriting the colors of 
 their male parents ; so that we must look to the law of 
 sexually limited transmission. 
 
 In all parts of the world both sexes of many soft-billed 
 birds, especially those which frequent reeds or hedges, are 
 obscurely -colored. No doubt if their colors had been 
 brilliant, they would have been much more conspicuous to 
 their enemies; but whether their dull tints have been 
 specially gained for the sake of protection seems, as far as 
 I can judge, rather doubtful. It is still more doubtful 
 whether such dull tints can have been gained for the sake 
 of ornament. We must, however, bear in mind that male 
 birds, though dull-colored, often differ much from their 
 females (as with the common sparrow), and this leads to 
 the belief that such colors have been gained through sexual 
 selection from being attractive. Many of the soft-billed 
 birds are songsters; and a discussion in a former chapter 
 should not be forgotten, in which it was shown that tti 
 best songsters are rarely ornamented with bright tints. It 
 would appear that female birds, as a general rule, have 
 selected their mates either for their sweet voices or gay 
 colors, but not for both charms combined. Some species 
 which are manifestly colored for the sake of protection,
 
 BIRDS. 559 
 
 such as the jack-snipe, woodcock and night- jar, are like- 
 wise marked and shaded, according to our standard of 
 taste, with extreme elegance. In such cases we may con- 
 clude that both natural and sexual selection have acted 
 conjointly for protection and ornament. Whether any 
 bird exists which does not possess some special attraction 
 by which to charm the opposite sex may be doubted. 
 When both sexes are so obscurely colored that it would 
 be rash to assume the agency of sexual selection, and when 
 no direct evidence can be advanced showing that such 
 colors serve as a protection, it is best to own complete 
 ignorance of the cause, or, which comes to nearly the same 
 thing, to attribute the result to the direct action of the 
 conditions of life. 
 
 Both sexes of many birds are conspicuously, though not 
 brilliantly, colored, such as the numerous black, white, or 
 piebald species; and these colors are probably the result of 
 sexual selection. With the common blackbird, capercailzie, 
 blackcock, black scoter- duck (Oidemia), and even with one 
 of the birds of paradise (Lophorina atra) the males alone 
 are black, while the females are brown or mottled; and 
 there can hardly be a doubt that blackness in these cases 
 has been a sexually selected character. Therefore, it is in 
 some degree probable that the complete or partial blackness 
 of both sexes in such birds as crows, certain cockatoos, 
 storks and swans, and many marine birds, is likewise the 
 result of sexual selection, accompanied by equal transmis- 
 sion to both sexes; for blackness can hardly serve in any 
 case as a protection. With several birds, in which the male 
 alone is black, and in others in which both sexes are black, 
 the beak or skin about the head is brightly colored, and 
 the contrast thus afforded adds much to their beauty; we 
 see this in the bright yellow beak of the male blackbird, in 
 the crimson skin over the eyes -of the blackcock and caper- 
 cailzie, in the brightly and variously colored beak of the 
 scoter-drake (Oidemia), in the red beak of the chough 
 (Corvus graculus, Linn.), of the black swan and the black 
 stork. ' This leads me to remark that it is not incredible 
 that toucans may owe the enormous size of their beaks to 
 sexual selection, for the sake of displaying the diversified 
 and vivid stripes of color with which these organs are 
 ornamented.* The naked skin, also, at the base of the 
 
 * No satisfactory explanation has ever been offered of the immense
 
 560 THE DESCENT OF MAN. 
 
 beak and round the eyes is likewise often brilliantly colored; 
 and Mr. Gould, in speaking of one species,* says that the 
 colors of the beak "are doubtless in the finest and most 
 brilliant state during the time of pairing." There is no 
 greater improbability that toucans should be encumbered 
 with immense beaks, though rendered as light as possible 
 by their cancellated structure, for the display of fine 
 colors (an object falsely appearing to us unimportant), 
 than that the male Argus pheasant and some other birds 
 should be encumbered with plumes so long as to impede 
 their flight. 
 
 In the same manner, as the males alone of various species 
 are black, the females being dull-colored; so in a few causes 
 the males alone are either wholly or partially white, as with 
 the several bell-birds of South America (Ohasmorhyuchus), 
 the Antarctic goose (Bernicla antarctica), the silver pheas- 
 ant, etc., while the females are brown or obscurely mottled. 
 Therefore, on the same principle as before, it is probable 
 that both sexes of many birds, such as white cockatoos, 
 several egrets with their beautiful plumes, certain ibises, 
 gulls, terns, etc., have acquired their more or less com- 
 pletely white plumage through sexual selection. In some 
 of these cases the plumage becomes white only at maturity. 
 This is the case with certain gannets, tropic-birds, etc., 
 and with the snow-goose (Anser hypcrloreus}. As the 
 latter breeds on the "barren grounds," when not covered 
 with snow, and as it migrates southward during the winter 
 there is no reason to suppose that its snow-white adult 
 plumage serves as a protection. In the Anastomus oscitans 
 we have still better evidence that the white plumage is a 
 nuptial character, for it is developed only during the 
 
 size, and still less of the bright colors, of the toucan's beak. Mr. 
 Bates (" The Naturalist on the Amazons," vol. ii, 1868, p. 341) states 
 that they use their beaks for reaching fruit at the extreme tips of the 
 branches; and likewise, as stated by other authors, for extracting 
 eggs and young birds from the nests of other birds. But, as Mr. 
 Bates admits, the beak "can scarcely be considered a very perfectly 
 formed instrument for the end to which it is applied." The great 
 bulk of the beak, ascshown by its breadth, depth, as well as length, 
 is not intelligible on the view, that it serves merely as an organ of 
 prehension. Mr. Belt believes (" The Naturalist in Nicaragua," p. 
 197) that the principal use of the beak is as a defense against 
 enemies, especially to the female while nesting in a hole in a tree. 
 * Rhainphastos carinatus, Gould's " Monograph of Rhamphastidae."
 
 BIRDS. 561 
 
 summer; the young in their immature state and the adulte 
 in their winter dress being gray and black. With many 
 kinds of gulls (Larus) the head and neck become pure 
 white during the summer, being gray or mottled during 
 the winter and in the young state. On the other hand, 
 with the smaller gulls, or sea-mews (Gavia) and with some 
 terns (Sterna) exactly the reverse occurs; for the heads of 
 the young birds during the first year, and of the adults during 
 the winter, are either pure white or much paler colored 
 than during the breeding-season. These latter cases offer 
 another instance of the capricious manner in which sexual 
 selection appears often to have acted.* 
 
 That aquatic birds have acquired a white plumage so 
 much oftener than terrestrial birds probably depends on 
 their large size and strong powers of flight, so that they 
 can easily defend themselves or escape from birds of prey, 
 to which, moreover, they are not much exposed. Conse- 
 quently sexual selection has not here been interfered with 
 or guided for the sake of protection. No doubt with birds 
 which roam over the open ocean, the males and females 
 could find each other much more easily when made con- 
 spicuous either by being perfectly white or intensely black; 
 so that these colors may possibly serve the same end as the 
 call-notes of many land-birds, f A white or black bird 
 when it discovers and flies down to a carcass floating on the 
 sea or cast upon the beach, will be seen from a great dis- 
 tance, and will guide other birds of the same and other 
 species to the prey; but as this would be a disadvantage to 
 the first finders, the individuals which were the whitest or 
 blackest would not thus procure more food than the less 
 strongly colored individuals. Hence conspicuous colors 
 cannot have been gradually acquired for this purpose 
 ( through natural selection. 
 
 As sexual selection depends on so fluctuating an element 
 
 *On Larus, Gavia and Sterna, see Macgiilivray, "Hist. Brit. 
 Birds," vol. v, pp. 515, 584, 626. On the Anser hyperboreus, Audu- 
 bon, " Ornitk. Biography," vol. iv, p, 562. On the Anastomus, Mr. 
 Blyth, in ' Ibis," 1867, p. 173. 
 
 f It may be noticed that with vultures, which roam far and wide 
 high in the air, like marine birds over the ocean, three or four species 
 are almost wholly or largely white, and that many others are black. 
 So that here again conspicuous colors may possibly aid the sexes in 
 finding each other during the breeding season.
 
 562 THE DESCENT OF MAN. 
 
 as taste, we can understand how it is that, within the same 
 group of birds having nearly the same habits, there should 
 exist white or nearly white, as well as black or nearly black, 
 species for instance, both white and black cockatoos, 
 storks, ibises, swans, terns and petrels. Piebald birds like- 
 wise sometimes occur in the same groups together with 
 black and white species; for instance, the black-necked 
 ewan, certain terns and the common magpie. That a strong 
 contrast in color is agreeable to birds we may conclude by 
 looking through any large collection, for the sexes often 
 differ from each other in the male having the pale parts of 
 a purer white, and the variously colored dark parts of still 
 darker tints than the female. 
 
 It would even appear that mere novelty, or slight 
 changes for the sake of change, have sometimes acted on 
 female birds as a charm, like changes of fashion with us. 
 Thus the males of some parrots can hardly be said to be 
 more beautiful than the females, at least according to our 
 taste, but they differ in such points, as in having a rose- 
 colored collar instead of "a bright, emeraldine, narrow 
 green collar;" or in the male having a black collar instead 
 of "a yellow demi-collar in front," with a pale roseate 
 instead of a plum-blue head.* As so many male birds 
 have elongated tail-feathers or elongated crests for their 
 chief ornament, the shortened tail, formerly described in 
 the male of a humming-bird, and the shortened crest of 
 the male goosander, seem like one of the many changes of 
 fashion which we admire in our own dresses. 
 
 Some members of the heron family offer a still more 
 curious case of novelty in coloring, having, as it appears, 
 been appreciated for the sake of novelty. The young of 
 the Ardea asha are white, the adults being dark slate- 
 colored; and not only the young, but the adults in their 
 winter plumage, of the allied Buphus coromandus are 
 white, this color changing into a rich golden-buff during 
 the breeding-season. It is incredible that the young of 
 these two species, as well as of some other members of the 
 same family, f should for any special purpose have been 
 
 *8ee Jerdon on the genus Palseornis, "Birds of India," vol. i, pp. 
 258-260. 
 
 f-Tke young of Ardea rufescens and A. cazrulea of the United 
 States are likewise white, the adults being colored in accordance
 
 BIRDS. 563 
 
 rendered pure white and thus made conspicuous to their 
 enemies; or that the adults of one of these two species 
 should have been specially rendered white during the 
 winter in a country which is never covered with snow. On 
 the other hand, we have good reason to believe that white- 
 ness has been gained by many birds as a sexual ornament. 
 We may therefore conclude that some early progenitor of 
 the Ardea asha and the Buphus acquired a white plumage 
 for nuptial purposes, and transmitted this color to their 
 young; so that the young and the old became white like 
 certain existing egrets; and that the whiteness was after- 
 ward retained by the young, while it was exchanged by the 
 adults for more strongly pronounced tints. But if we 
 could look still further back to the still earlier progenitors 
 of these two species we should probably see the adults dark- 
 colored. I infer that this would be the case from the 
 analogy of many other birds which are dark while young 
 and when adult are white; and more especially from the 
 case of the Ardea gularis, the colors of which are the 
 reverse of those of A. asha, for the young are dark-colored, 
 and the adults white, the young having retained a forme* 
 state of plumage. It appears therefore that during a lonj 1 
 line of descent, the adult progenitors of the Ardea asha> 
 the Buphus, and of some allies, have undergone the follow- 
 ing changes of color: fiistly, a dark shade; secondly, pure 
 white, and thirdly, owing to another change of fashion (if 
 I may so express myself), their present slaty, reddish, or 
 golden-buff tints. These successive changes are intelligi- 
 ble only on the principle of novelty having been admired 
 by birds for its own sake. 
 
 Several writers have objected to the whole theory of 
 sexual selection by assuming that with animals and savages 
 the taste of the female for certain colors or other ornaments 
 would not remain constant for many generations; that first 
 one color and then another would be admired, and conse- 
 quently that no permanent effect could be produced. We 
 may admit that taste is fluctuating, but it is not quite arbi- 
 trary. It depends much on habit, as we see in mankind ; 
 and we may infer that this would hold good with birds and 
 
 with their specific names. Audubon (" Ornith. Biography," vol. iii, 
 p. 416; vol. iv, p. 58) seems rather pleased at the thought that thia 
 remarkable change of plumage will greatly "disconcert the system- 
 atists."
 
 564 THE DESCENT OF MAN. 
 
 other animals. Even in our own dress the general charactel 
 lasts long, and the changes are to a certain extent gradu- 
 ated. Abundant evidence will be given in two places in a 
 future chapter that savages of many races have admired for 
 many generations the same cicatrices on the skin, the same 
 hideously perforated lips, nostrils, or ears, distorted heads, 
 etc.; and these deformities present some analogy to the 
 natural ornaments of various animals. Nevertheless, with 
 savages such fashions do not endure forever, as we may 
 infer from the differences in this respect between allied 
 tribes on the same continent. So, again, the raisers of 
 fancy animals certainly have admired for many generations 
 and still admire the same breeds; the}' earnestly desire 
 slight changes, which are considered as improvements, but 
 any great or sudden change is looked at as the greatest 
 blemish. With birds in a state of nature we have no 
 reason to suppose that they would admire an entirely new 
 style of coloration, even if great and sudden variations 
 often occurred, which is far from being the case. We know 
 that dove-cote pigeons do not willingly associate with the 
 variously colored fancy breeds; that albino birds do not 
 commonly get partners in marriage; and that the black 
 ravens of the Feroe Islands chase away their piebald 
 brethren. But this dislike of a sudden change would not 
 preclude their appreciating slight changes any more than it 
 does in the case of man. Hence, with respect to taste, 
 which depends on many elements, but partly on habit and 
 partly on a love of novelty, there seems no improba- 
 bility in animals admiring for a very long period the 
 same general style of ornamentation or other attractions, 
 and yet appreciating slight changes in colors, form, or 
 sound. 
 
 Summary of the Four Chapters on Birds. Most male 
 birds are highly pugnacious during the breeding-season, and 
 some possess weapons adapted for fighting with their rivals. 
 But the most pugnacious and the best armed males rarely 
 or never depend for success solely on their power to drive 
 away or kill their rivals, but have special means for charm- 
 ing the female. With some it is the power of song, or of 
 giving forth strange cries, or instrumental music, and the 
 males in consequence differ from the females in their vocal 
 organs, or in the structure of certain feathers. From the
 
 BIRDS. 565 
 
 curiously diversified means for producing various sounds we 
 gain a high idea of the importance of this means of court- 
 ship. Many birds endeavor to charm the females by love 
 dances or antics performed on the ground or in the air, and 
 sometimes at prepared places. But ornaments of many 
 kinds, the most brilliant tints, combs and wattles, beautiful 
 plumes, elongated feathers, top-knots, and so forth, are by 
 far the commonest means. In some cases mere novelty 
 appears to have acted as a charm. The ornaments of the 
 males must be highly important to them, for they have 
 been acquired in not a few cases at the cost of increased 
 danger from enemies, and even at some loss of power in 
 lighting with their rivals. The males of very many species 
 do not assume their ornamental dress until they arrive at 
 maturity, or they assume it only during the breeding-season, 
 or the tints then become more vivid. Certain ornamental 
 appendages become enlarged, turgid, and brightly colored 
 during the act of courtship. The males display their 
 charms with elaborate care and to the best effect; and this 
 is done in the presence of the females. The courtship is 
 sometimes a prolonged affair, and many males and females 
 congregate at an appointed place. To suppose that the 
 females do not appreciate the beauty of the males is to 
 admit that their splendid decorations, all their pomp and 
 display, are useless; and this is incredible. Birds have fine 
 powers of discrimination, and in some few instances it can 
 be shown that they have a taste for the beautiful. The 
 females, moreover, are known occasionally to exhibit a 
 marked preference or antipathy for certain individual 
 males. 
 
 If it be admitted that the females prefer, or are uncon- 
 sciously excited by the more beautiful males, then the 
 males would slowly but surely be rendered more and more 
 attractive through sexual selection. That it is this sex 
 which has been chiefly modified, we may infer from the 
 fact that, in almost every genus where the sexes differ, the 
 males differ much more from one another than do the 
 females; this is well shown in certain closely allied repre- 
 sentative species, in which the females can hardly be dis- 
 tinguished, while the males are quite distinct. Birds in a 
 state of nature offer individual differences which would 
 amply suffice for the work of sexual selection; but we have 
 eeen that they occasionally present more strongly marked
 
 566 THE DESCENT OF MAN. 
 
 variations which recur so frequently that they would imme- 
 diately be fixed, if they served to allure the female. The 
 laws of variation must determine the nature of the initial 
 changes, and will have largely influenced the final result. 
 The gradations, which may be observed between the males 
 of allied species, indicate the nature of the steps through 
 which they have passed. They explain also in the most 
 interesting manner how certain characters have originated, 
 such as the indented ocelli on the tail-feathers of the pea- 
 cock, and the ball-and-socket ocelli on the wing- feathers 
 of the Argus pheasant. It is evident that the brilliant 
 colors, top-knots, fine plumes, etc., of many male birds 
 cannot have been acquired as a protection; indeed, they 
 sometimes lead to danger. That they are not due to the 
 direct and definite action of the conditions of life, we may 
 feel assured, because the females have been exposed to the 
 same conditions, and yet often differ from the males to an 
 extreme degree. Although it is probable that changed 
 conditions acting during a lengthened period have in some 
 cases produced a definite effect on both sexes, or some- 
 times on one sex alone, the more important result will have 
 been an increased tendency to var^ or to present more 
 strongly marked individual differs -..as; and such differ- 
 ences will have afforded an excellent groundwork for the 
 action of sexual selection. 
 
 The laws of inheritance, irrespectively of selection, 
 appear to have determined whether the characters acquired 
 by the males for the sake of ornament, for producing vari- 
 ous sounds and for fighting together, have been transmitted 
 to the males alone or to both sexes either permanently or 
 periodically during certain seasons of the year. Why 
 various characters should have been transmitted sometimes 
 in one way and sometimes in another is not in most cases 
 known; but the period of variability seems often to have 
 been the determining cause. When the two sexes have 
 inherited all characters in common they necessarily resem- 
 ble each other; but as the successive variations may be 
 differently transmitted every possible gradation may be 
 found, even within the same genus, from the closest simi- 
 larity to the widest dissimilarity between the sexes. AVith 
 many closely allied species, following nearly the same 
 habits of life, the males have come to differ from each 
 other chiefly through the action of sexual selection; while
 
 BIRDS. 567 
 
 the females have come to differ chiefly from partaking 
 more or less of the characters thus acquired by the males. 
 The effects, moreover, of the definite action of the condi- 
 tions of life will not have been masked in the females as 
 in the males by the accumulation through sexual selection 
 of strongly pronounced colors and other ornaments. The 
 individuals of both sexes, however affected, will have been 
 kept at each successive period nearly uniform by the free 
 intercrossing of many individuals. 
 
 With species in which the sexes differ in color it is possi- 
 ble or probable that some of the successive variations often 
 tended to be transmitted equally to both sexes; but that 
 when this occurred the females were prevented from acquir- 
 ing the bright colors of the males by the destruction which 
 they suffered during incubation. There is no evidence 
 that it is possible by natural selection to convert one form 
 of transmission into another. But there would not be the 
 least difficulty in rendering a female dull-colored, the male 
 being still kept bright-colored, by the selection of suc- 
 cessive variations which were from the first limited in their 
 transmission to the same sex. Whether the females of 
 many species have actually been thus modified must at 
 present remain doubtful. When, through the law of the 
 equal transmission of characters to both sexes, the females 
 were rendered as conspicuously colored as the males, their 
 instincts appear often to have been modified so that they 
 were led to build domed or concealed nests. 
 
 In one small and curious class of cases the characters 
 and habits of the two sexes have been completely trans- 
 posed, for the females are larger, stronger, more vociferous 
 and brighter colored than the males. They have also be- 
 come so quarrelsome that they often fight together for the 
 possession of the males like the males of other pugnacious 
 species for the possession of the females. If, as seems 
 probable, such females habitually drive aways their rivals, 
 and by the display of their bright colors or other charms 
 endeavor to attract the males, we can understand how it is 
 that they- have gradually been rendered by sexual selection 
 and sexually limited transmission more beautiful than the 
 males the latter being left unmodified or only slightly 
 modified. 
 
 Whenever the law of inheritance at corresponding ages
 
 568 THE DESCENT OF NAN. 
 
 prevails, but not that of sexually limited transmission, then 
 if the parents vary late in life and we know that this con- 
 stantly occurs with our poultry and occasionally with other 
 birds the young will be left unaffected, while the adults 
 of both sexes will be modified. If both these laws of 
 inheritance prevail and either sex varies late in life, that 
 sex alone will be modified, the other sex and the young 
 being unaffected. When variations in brightness or in 
 other conspicuous characters occur early in life, as no doubt 
 often happens, they will not be acted on through sexual 
 selection until the period of reproduction arrives; conse- 
 quently if dangerous to the young they will be eliminated 
 through natural selection. Thus we can understand how 
 it is that variations arising late in life have so often been 
 preserved for the ornamentation of the males; the females 
 and the young being left almost unaffected, and therefore 
 like each other. With species having a distinct summer 
 and winter plumage, the males of which either resemble or 
 differ from the females during both seasons or during the 
 summer alone, the degrees and kinds of resemblance 
 between the young and the old are exceedingly complex; 
 and this complexity apparently depends on characters, first 
 acquired by the males, being transmitted in various ways 
 and degrees, as limited by age, sex and season. 
 
 As the young of so many species have been but little 
 modified in color and in other ornaments, we are enabled 
 to form some judgment with respect to the plumage of their 
 early progenitors; and we may infer'that the beauty of our 
 existing species, if we look to the whole class, has been 
 largely increased since that period, of which the immature 
 plumage gives us an indirect record. Many birds, espe- 
 cially those which live much on the ground, have undoubt- 
 edly been obscurely colored for the sake of protection. In 
 some instances the upper exposed surface of the plumage 
 has been thus colored in both sexes, while the lower surface 
 in the males alone has been variously ornamented through 
 sexual selection. Finally, from the facts given in these 
 four chapters, we may conclude that weapons for battle, 
 organs for producing sound, ornaments of many kinds, 
 bright and conspicuous colors, have generally been acquired 
 by the males through variation and sexual selection and 
 have been transmitted in various ways according to the
 
 BIRDS. 569 
 
 several laws of inheritance the females and the young 
 being left comparatively but little modified.* 
 
 * I am greatly indebted to the kindness of Mr. Sclater for having 
 looked over these four chapters on birds, and the two following ones 
 on mammals. In this way I have been saved from making mistakes 
 about the names of the species, and from stating anything as a fact 
 which is known to this distinguished naturalist to be erroneous. 
 But of course he is not at all answerable for the accuracy of the 
 statements quoted by me from various authorities.
 
 570 THE DESCENT OF MAN. 
 
 CHAPTER XVII. 
 
 SECONDARY SEXUAL CHARACTERS OF MAMMALS. 
 
 The law of battle Special weapons, confined to the males Cause of 
 absence of weapons in the female Weapons common to both 
 sexes, yet primarily acquired by the male Other uses of such 
 weapons Their high importance Greater size of the male 
 Means of defense On the preference shown by either sex in the 
 ' pairing of quadrupeds. 
 
 WITH mammals the male appears to win the female 
 much more through the law of battle than through the 
 display of his charms. The most timid animals, not pro- 
 vided with any special weapons for fighting, engage in des- 
 perate conflicts during the season of love. Two male hares 
 have been seen to fight together until one was killed; male 
 moles often fight, and sometimes with fatal results ; male 
 squirrels engage in frequent contests, <( and often wound 
 each other severely;" as do male beavers, so that " hardly 
 a skin is without scars."* I observed the same fact with 
 the hides of the guanacoes in Patagonia; and on one occa- 
 sion several were so absorbed in fighting that they fear- 
 lessly rushed close by me, Livingstone speaks of the males 
 of the many animals in Southern Africa as almost invari- 
 ably showing the scars received in former contests. 
 
 The law of battle prevails with aquatic as with terrestrial 
 mammals. It is notorious how desperately male seals fight, 
 both with their teeth and claws, during the breeding- 
 season ; and their hides are likewise often covered with 
 scars. Male sperm-whales are very jealous at this season; 
 and in their battles :f they often lock their jaws together 
 
 * See Waterton's account of two hares fighting, " Zoologist, " vol . 
 i, 1843, p. 211. On moles, Bell, "Hist, of British Quadrupeds," 1st 
 edit., p. 100. On squirrels, Audubon and Bachman, 'Viviparous 
 Quadrupeds of North America," 1846, p. 269. On beavers, Mr. A. 
 H. Green, in " Journal of Lin. Soc. Zoolog.," vol. x, 1869, p. 362.
 
 MAMMALS. 571 
 
 and turn on their sides and twist about; 1 * so that their 
 lower jaws often become distorted.* 
 
 All male animals which are furnished with special weap- 
 ons for fighting are well known to engage in fierce battles. 
 The courage and the desperate conflicts of stags have often 
 described; their skeletons have been found in various 
 fcs of the world, with the horns inextricably locked 
 jther, showing how miserably the victor and vanquished 
 perished, f No animal in the world is so dangerous as 
 jm elephant in must. Lord Tankerville has given me a 
 graphic description of the battles between the wild bulls 
 in Chillingham Park, the descendants, degenerated in size 
 but not in courage, of the gigantic Bos ^rimigenius. 
 In 1861 several contended for mastery; and it was observed 
 that two of the younger bulls attacked in concert the old 
 leader of the herd, overthrew and disabled him, so that he 
 was believed by the keepers to be lying mortally wounded 
 in a neighboring wood. But a few days afterward one of 
 the young bulls approached the wood alone; and then the 
 "monarch of the chase," who had been lashing himself up 
 for vengeance, came out, and, in a short time, killed his 
 antagonist. He then quietly joined the herd, and long held 
 undisputed sway. Admiral Sir B. J. Sulivan informs me 
 that, when he lived in the Falkland Islands, he imported a 
 young English stallion, which frequented the hills near 
 Port William with eight mares. On these hills there were 
 two wild stallions, each with a small troop of mares; " and 
 it is certain that these stallions would never have approached 
 each other without fighting. Both had tried singly to fight 
 the English horse and drive away his mares, but had failed. 
 One day they came in together and attacked him. This was 
 seen by the capitan who had charge of the horses, and who, 
 on riding to the spot, found one of the two stallions 
 
 * On the battles of seals, see Capt. C. Abbott, in " Proc. Zool. 
 Soc.," 1868, p. 191; also Mr. R. Brown, ibid, 1868, p. 436; also L, 
 Lloyd, " Game Birds of Sweden," 1867, p. 412, also Pennant. On 
 the sperin-whale see Mr. J. H. Thompson, in " Proc. Zool. Soc.," 
 1367, p. 246. 
 
 f See Scrope (" Art of Deer- Stalking," p. 17) on the locking of the 
 horns with the Genus elaphus. Richardson, in " Fauna Bor. Amer- 
 icana," 1829, p. 252, says that the wapiti, moose and reindeer have 
 been found thus locked together. Sir A. Smith found at the Cape 
 of Good Hope the skeletons of two gnus in the same condition.
 
 572 THE DESCENT OF MAN. 
 
 engaged with the English horse, while the other was driv- 
 ing away the mares, and had already separated four from 
 the rest. The capitan settled the matter hy driving the 
 whole party into the corral, for the wild stallions would not 
 leave the mares." 
 
 Male animals which are provided with efficient cutting 
 or tearing teeth for the ordinary purposes of life, such as 
 the carnivora, insectivora, and rodents, are seldom furnished 
 with weapons especially adapted lor fighting with their rivals. 
 The case is very different with the males of many other 
 animals. We see this in the horns of stags and of certain 
 kinds of antelopes in which the females are hornless. With 
 many animals the canine teeth in the upper or lower jaw, 
 or in both, are much larger in the males than in the 
 females, or are absent in the latter, with the exception 
 sometimes of a hidden rudiment. Certain antelopes, the 
 musk-deer, camel, horse, boar, various apes, seals, and the 
 walrus, offer instances. In the females of the walrus the 
 tusks are sometimes quite absent.* In the male elephant 
 of India and in the male dugong f the upper incisors form 
 offensive weapons. In the male narwhal the left canine 
 alone is developed into the well-known, spirally-twisted, so- 
 called horn, which is sometimes from nine to ten feet in 
 length. It is believed that the males use these horns for 
 fighting together; for "an unbroken one can rarely be got, 
 and occasionally one may be found with the point of 
 another jammed into the broken place. "J The tooth on 
 the opposite side of the head in the male consists of a rudi- 
 ment about ten inches in length, which is embedded in the 
 jaw; but sometimes, though rarely, both are equally devel- 
 oped on the two sides. In the female both are always rudi- 
 mentary. The male cachalot has a larger head than that 
 
 * Mr. Lament ("Seasons with the Sea-Horses," 1861, p. 143) says 
 that a good tusk of the male walrus weighs four pounds, and is 
 longer than that of the female, which weighs about three pounds. 
 The males are described as fighting ferociously. On the occasional 
 absence of the tusks in the female, see Mr. R. Brown, " Proc. ZooL 
 Soc.," 1868, p. 429. 
 
 f Owen, " Anatomy of Vertebrates," vol. iii, p. 283. 
 
 | Mr. R. Brown, in "Proc. Zool. Soc.," 1869, p, 553. See Prof 
 Turner, in "Journal of Anat. and Phys., ; ' 1872, p. 76, on the homo- 
 logical nature of these tusks. Also Mr. J. W. Clarke on two tusks 
 being developed in the males, iu " Proc. Zoolog. Soo.," 1871, p. 48.
 
 MAMMALS. 573 
 
 of the female, and it no doubt aids him in his aquatic 
 battles. Lastly, the adult male ornithorhynchus is provided 
 with a remarkable apparatus, namely, a spur on the fore 
 leg, closely resembling the poison-fang of a venomous 
 snake ; but, according to Harting, the secretion from 
 the gland is not poisonous ; and on the leg of the female 
 there is a hollow, apparently for the reception of the spur.* 
 
 When the males are provided with weapons which in 
 the females are absent, there can hardly be a doubt that 
 these serve for fighting with other males; and that they 
 were acquired through sexual selection and were transmitted 
 to the male sex alone. It is not probable, at least in most 
 cases, that the females have been prevented from acquiring 
 such weapons, on account of their being useless, super- 
 fluous, or in some way injurious. On the contrary, as they 
 are often used by the males for various purposes, more espe- 
 cially as a defense against their enemies, it is a surprising 
 fact that they are so poorly developed, or quite absent in 
 the females of so many animals. With female deer the 
 development during each recurrent season of great branch- 
 ing horns, and with female elephants the development of 
 immense tusks would be a great waste of vital power, sup- 
 posing that they were of no use to the females. Conse- 
 quently they would have tended to be eliminated in the 
 female through natural selection; that is, if the successive 
 variations were limited in their transmission to the female 
 sex, for otherwise the weapons of the males would have 
 been injuriously affected, and this would have been a greater 
 evil. On the whole, and from the consideration of the fol- 
 lowing facts, it seems probable that when the various 
 weapons differ in the two sexes this has generally depended 
 on the kind of transmission which has prevailed. 
 
 As the reindeer is the one species in the whole family of 
 deer in which the female is furnished with horns, though 
 they are somewhat smaller, thinner and less branched than 
 in the male, it might naturally be thought that at least, in 
 this case, they must be of some special service to her. The 
 female retains her horns from the time when they are fully 
 developed, namely, in September, throughout the winter 
 
 * Owen on the cachalot and Ornithorhynchus, ibid, vol. iii, pp 
 638, 641. Harting is quoted by Dr. Zouteveen in the Dutch translat 
 of this work, vol. ii, p. 292.
 
 574 THE DESCENT OF MAN. 
 
 until April or May, when she brings forth her young. Mr. 
 Crotch made particular inquiries for me in Norway, and it 
 appears that the females at this season conceal themselves 
 for about a fortnight in order to bring forth their young, 
 and then reappear generally hornless. In Nova Scotia, 
 however, as I hear from Mr. H. Reeks, the female some- 
 times retains her horns longer. The male, on the other 
 hand, casts his horns much earlier, toward the end of 
 November. As both sexes have the same requirements and 
 follow the same habits of life, and as the male is destitute 
 of horns during the winter, it is improbable that they can 
 be of any special service to the female during this season, 
 which includes the larger part of the time during which 
 she is horned. Nor is it" probable that she can have 
 inherited horns from some ancient progenitor of the family 
 of deer, for, from the fact of the females of so many species 
 in all quarters of the globe not having horns, we may con- 
 clude that this was the primordial character of the group.* 
 The horns of the reindeer are developed at a most 
 unusually early age; but what the cause of this may be is 
 not known. The effect has apparently been the transfer- 
 ence of the horns to both sexes. We should bear in mind 
 that horns are always transmitted through the female, and 
 that she has a latent capacity for their development, as we 
 see in old or diseased females, f Moreover, the females of 
 some other species of deer exhibit either normally or occa- 
 sionally rudiments of horns; thus the female of Cervulus 
 moschatus has " bristly tufts, ending in a knob instead of 
 a horn;" and "in most specimens of the female wapiti 
 ( Cervus canadensis) there is a sharp, bony protuberance in 
 the place of the horn."| From these several considera- 
 
 *On the structure and shedding of the horns of the reindeer, 
 Hoffberg, " Amoenitates Acad.," vol. iv, 1788, p. 149. See Richard- 
 son, "Fauna Bor. Americana," p. 241, in regard to the American 
 variety or species; also Maj. W. Ross King, " The Sportsman in 
 Canada/' 1866, p. 80. 
 
 t Isidore Geoffrey St. Hilaire, " Essais de Zoolog. Generate," 1841, 
 p. 513. Other masculine characters besides the horns, are sometimes 
 wmilarly transferred to the female; thus Mr. Boner, in speaking of 
 n old female chamois ("Chamois Hunting in the Mountains of 
 Bavaria," 1860, 2nd edit., p. 363) says, "not only was the head very 
 male-looking, but along the back there was a ridge of long hair, 
 usually to be found only in bucks." 
 
 JOn the Cervulus, Dr. Gray, "Catalogue of Mammalia in th
 
 MAMMALS. 675 
 
 tions we may conclude that the possession of fairly well- 
 developed horns by the female reindeer is due to the males 
 having first acquired them as weapons for fighting with 
 other males; and secondarily to their development from 
 Borne unknown cause at an unusually early age in the males 
 and their consequent transference to both sexes. 
 
 Turning to the sheath-horned ruminants: with ante- 
 lopes a graduated series can be formed, beginning with 
 species, the females of which are completely destitute of 
 horns passing on to those which have horns so small as to 
 be almost rudimentary (as with the Antilocapra amencana, 
 in which species they are present in only one out of four 
 or five females*) to those which have fairly developed 
 horns, but manifestly smaller and thinner than in the 
 male and sometimes of a different shapef and ending 
 with those in which both sexes have horns of equal size. 
 As with the reindeer, so with antelopes, there exists, as 
 previously shown, a relation between the period of the devel- 
 opment of the horns and their transmission to one or both 
 sexes; it is therefore probable that their presence or ab- 
 sence in the females of some species and their more or less 
 perfect condition in the females of other species depends, 
 not on their being of any special use, but simply in inherit- 
 ance. It accords with this view that even in the same 
 restricted genus both sexes of some species, and the males 
 alone of others, are thus provided. It is also a remarkable 
 fact that, although the females of Antilope bezoartica are 
 normally destitute of horns, Mr. Blyth has seen no less 
 than three females thus furnished; and there was no reason 
 to suppose that they were old or diseased. 
 
 In all the wild species of goats and sheep the horns are 
 larger in the male than in the female, and are sometimes 
 quite absent in the latter. J In several domestic breeds of 
 these two animals, the males alone are furnished with 
 
 British Museum," part iii, p. 220. On the Cervutt canadensis or 
 wapiti, see Hon. J. D. Caton, "Ottawa Acad. of Nat. Sciences," May, 
 1868, p. 9, 
 
 *I am indebted to Dr. Canfield for this information; see also his 
 paper in "Proc. Zoolog. Soc.," 1866, p. 105. 
 
 f For instance, the horns of the female Ant. eucJiore resemble those 
 of a distinct species, viz., the Ant. dorcas var. Corine, see Desmarest, 
 " Mammalogie," p. 455. 
 
 JGray, "Catalogue Marnm. Brit. Mus.," part iii, 1852, p. 160.
 
 576 THE DESCENT OF MAN. 
 
 horns; and in some breeds, for instance, in the sheep of 
 North Wales, though both sexes are properly homed, the 
 ewes are very liable to be hornless. I have been informed 
 by a trustworthy witness, who purposely inspected a flock 
 of these same sheep during the lambing season, that the 
 horns at birth are generally more fully developed in the male 
 than in the female. Mr. J. Peel crossed his Lonk sheep, 
 both sexes of which always bear horns, with hornless Lei-\ 
 cesters and hornless Shropshire Downs; and the result was 
 that the male offspring had their horns considerably 
 reduced, while the females were wholly destitute of them. 
 These several facts indicate that, with sheep, the horns are 
 a much less firmly fixed character in the females than in the 
 males; and this leads us to look at the horns as properly of 
 masculine origin. 
 
 With the adult musk-ox (Ovibos moschatus) the horns 
 of the male are larger than those of the female, and in the 
 latter the bases do not touch. * In regard to ordinary 
 cattle Mr. Blyth remarks: " In most of the wild bovine 
 animals the horns are both longer and thicker in the bull 
 than in the cow, and in the cowbanteng (Bos sondaicus) 
 the horns are remarkably small, and inclined much back- 
 ward. In the domestic races of cattle, both of the humped 
 and humpless types, the horns are short and thick in the 
 bull, longer and more slender in the cow and ox; and in 
 the Indian buffalo, they are shorter and thicker in the bull, 
 longer and more slender in thp cow. In the wild gaour (B. 
 gaurus) the horns are mostly both longer and thicker in 
 the bull than in the cow/'f Dr. Forsyth Major also 
 informs me that a fossil skull, believed to be that of the 
 female Bos estruscus, has been found in Val d'Arno, 
 which is wholly without horns. In the Rhinoceros simus, 
 as I may add, the horns of the female are generally longer 
 but less powerful than in the male; and in some other 
 species of rhinoceros they are said to be shorter in the 
 female. \ From these various facts we may infer as probable 
 that horns of all kinds, even when they are equally devel- 
 oped in the two sexes, were primarily acquired by the male 
 
 * Richardson, " Fauna Bor. Americana," p. 278. 
 f " Land and Water," 1867, p. 346. 
 
 fSir Andrew Smith, "Zoology of S. Africa," pi. xix. Owen. 
 " Anatomy of Vertebrates," vol. iii, p. 624.
 
 MAMMALS. 577 
 
 in order to conquer other males, and have been transferred 
 more or less completely to the female. 
 
 The effects of castration deserve notice, as thro wing light on 
 this same point. Stags after the operation never renew their 
 horns. The male reindeer, however, must be excepted, as 
 after castration he does renew them. This fact, as well as 
 the possession of horns by both sexes, seems at first to prove 
 that the horns in this species do not constitute a sexual 
 character; * but as they are developed at a very early age, 
 before the sexes differ in constitution, it is not surprising 
 that they should be unaffected by castration, even if they 
 were aboriginally acquired by the male. With sheep 
 botli sexes properly bear horns; and I am informed 
 that with Welsh sheep the horns of the males are con- 
 siderably reduced by castration ; but the degree depends 
 much on the age at which the operation is performed, as 
 is likewise the case with other animals. Merino rams have 
 large horns, while the ewes, "generally speaking, are with- 
 out horns;" and in this breed castration seems to produce 
 a somewhat greater effect, so that if performed at an early 
 age the horns " remain almost undeveloped. "\ On the 
 Guinea coast there is a breed in which the females never 
 bear horns, and, as Mr. Winwood Keade informs me, the 
 rams after castration are quite destitute of them. With 
 cattle the horns of the males are much altered by castration; 
 for, instead of being short and thick, they become longer 
 than those of the cow, but otherwise resemble them. The 
 Ant Hope bezoartica offers a somewhat analogous case; the 
 males have long straight spiral horns nearly parallel to each 
 other, and directed backward; Ljuo females occasionally bear 
 horns, but these when present, lire of a very different shape, 
 for they are not spiral, and upiejiding widely bend round 
 with the points forward. Now it is a remarkable fact that 
 in the castrated male, as Mi Blyth informs me, the horns 
 are of the same peculiar shape us in the female, but longer 
 
 *This is the conclusion of SekHHz, "Die Darwinsche Theorie," 
 1871, p. 47. 
 
 f I arn much obliged to Prot. V ictor Carus for having made in- 
 quiries for me in Saxony on this subject. H. von Nathusius 
 (" Viehzucht," 1872, p. 64) says <.liat the horns of sheep castrated at 
 an early period, either altogether disappear or remain as mere rudi- 
 ments; but I do not know whetliei he refers to merinos or to ordinary 
 breeds.
 
 578 TEE DESCENT OF MAN. 
 
 and thicker. If we may judge from analogy, the female 
 probably shows us in these two cases of cattle and the 
 antelope the former condition of the horns in some early 
 progenitor of each species. But why castration should lead 
 to the reappearance of an early condition of the horns 
 cannot be explained with any certainty. Nevertheless, it 
 seems probable, that in nearly the same manner as the con- 
 stitutional disturbance in the offspring, caused by a cross 
 between two distinct species or races, often leads to the 
 reappearance of long-lost characters;* so here the disturb- 
 ance in the constitution of the individual, resulting from 
 castration, produces the same effect. 
 
 The tusks of the elephant in the different species or races 
 differ according to sex, nearly as do the horns of ruminants. 
 In India and Malacca the males alone are provided with 
 well-developed tusks. The elephant of Ceylon is con- 
 sidered by most naturalists as a distinct race, but by some 
 as a distinct species, and here " not one in a hundred is 
 found with tusks, the few that possess them being exclu- 
 sively males."f The African elephant is undoubtedly dis- 
 tinct, and the female has large well-developed tusks, 
 though not so large as those of the male. 
 
 These differences in the tusks of the several races and 
 species of elephants the great variability of the horns of 
 deer, as notably in the wild reindeer the occasional presence 
 of horns in the female Antilope Bezoartica and their frequent 
 absence in the female of Antilocapra americana the pres- 
 ence of two tusks in some few male narwhals the complete 
 absence of tusks in some female walruses are all instances 
 of the extreme variability of secondary sexual characters, 
 and of their liability to differ in closely allied forms. 
 
 Although tusks and horns appear in all cases to have 
 been primarily developed as sexual weapons, they often 
 serve other purposes. The elephant uses his tusks in 
 attacking the tiger; according to Bruce, he scores the 
 trunks of trees until they can be thrown down easily, and 
 he likewise thus extracts the farinaceous cores of palms; in 
 
 *I have given various experiments and other evidence proving 
 that this is the case, in my " Variation of Animate and Plants under 
 Domestication," vol. ii, 1868, pp. 39-47. 
 
 fSir J. Emerson Tennent, "Ceylon," 1859, vol. ii, p. 274. For 
 Malacca, "Journal of Indian Archipelago," vol. iv, p. 857.
 
 MAMMALS. 579 
 
 Africa lie often uses one tusk, 'always the same, to probe 
 the ground and thus ascertain whether it will bear his 
 weight. The common bull defends the herd with his 
 horns; and the elk in Sweden has been known, according 
 to Lloyd, to strike a wolf dead with a single blow of his 
 great horns. Many similar facts could be given. One of 
 the most curious secondary uses to which the horns of an 
 animal may be occasionally put is that observed by Capt. 
 Hutton * with the wild goat (Capra cegagrus) of the Hima- 
 layas and, as it is also said with the ibex, namely, that 
 when the male accidentally falls from a height he bends 
 inward his head, and, by alighting on his massive horns, 
 breaks the shock. The female cannot thus use her horns, 
 which are smaller, but from her more quiet disposition she 
 does not need this strange kind of shield so much. 
 
 Each male animal uses his weapons in his own peculiar 
 fashion. The common ram makes a charge and butts with 
 such force with the bases of his horns that I have seen a 
 powerful man knocked over like a child. Goats and cer- 
 tain species of sheep, for instance the Ovis cydoceros of 
 Afghanistan,! rear on their hind legs, and then not only 
 butt, but " make a cut down and a jerk up, with the ribbed 
 front of their cimeter-shaped horn, as with a saber. When 
 the 0. cyclocerus attacked a large domestic ram, who was a 
 noted bruiser, he conquered him by the sheer novelty of 
 his mode of fighting, always closing at once with his 
 adversary, and catching him across the face and nose with 
 a sharp, drawing jerk of the head, and then bounding out 
 of the way before the blow could be returned." In Pem- 
 brokeshire a male goat, the master of a flock which during 
 several generations had run wild, was known to have killed 
 several males in single combat; this goat possessed enormous 
 horns, measuring thirty-nine inches in a straight line from 
 tip to tip. The common bull, as every one knows, gores 
 and tosses his opponent; but the Italian buffalo is said 
 never to use his horns; he gives a tremendous blow with 
 his convex forehead, and then tramples on his fallen enemy 
 with his knees an instinct which the common bull doea 
 
 * " Calcutta Journal of Nat. Hist.," vol. ii, 1843, p. 526. 
 'Mr. Blyth, in "Land and Water," March, 1867, p. 134, on the 
 authority of Capt. Hutton and others. For the wild Pembrokeshire 
 goats, see the "Field," 1869, p- 150
 
 580 THE DESCENT OF MAN. 
 
 not possess.* Hence, a dog who pins a buffalo by the nose 
 is immediately crushed. We must, however, remember 
 that the Italian buffalo has been long domesticated, and it 
 is by no means certain that the wild parent-form had simi- 
 lar horns. Mr. Bartlett informs me that when a female 
 Cape buffalo (Bubalus caffer) was turned into an inclosure 
 with a bull of the same species she attacked him, and he in 
 return pushed her about with great violence. But it was 
 manifest to Mr. Bartlett that, had not the bull shown 
 dignified forbearance, he could easily have killed her by a 
 single lateral thrust with his immense horns. The giraffe 
 uses his short, hair- covered horns, which are rather longer 
 in the male than in the female, in a curious manner; for, 
 
 Fig. 63. Oryx leucoryx, male <from the Knowsley Menagerie). 
 
 with his long neck, he swings his head to either side, 
 almost upside down, with such force that I have seen 
 a hard plank deeply indented by a single blow. 
 
 With antelopes it is sometimes difficult to imagine how 
 they can possibly use their curiously shaped horns ; thus 
 the springboc (Ant. euchore) has rather short upright 
 horns, with the sharp points bent inward, almost at right 
 angles, so as to face each other ; Mr. Bartlett does not 
 know how they are used, but suggests that they would 
 inflict a fearful wound down each side of the face of an 
 antagonist. The slightly curved horns of the Oryx leu- 
 (fig. 63) are directed backward, and are of such 
 
 *M. E. M. Bailly, " Sur 1'usage des Comes," etc., " Annal des Sc. 
 Nat.," tern, ii, 1824, p. 869.
 
 MAMMALS. 581 
 
 length that their pointa reach beyond the middle of the 
 back, over which they extend in almost parallel lines. 
 Thus they seem singularly ill-fitted for fighting ; but 
 Mr. Bartlett informs me that when two of these animals 
 preprare for battle they kneel down, with their heads 
 between their fore legs, and in this attitude the horns 
 etand nearly parallel and close to the ground, with the 
 points directed forward and a little upward. The combat- 
 ants then gradually approach each other, and each endeav- 
 ors to get the upturned points under the body of the other; 
 if one succeeds in doing this, he suddenly springs up, 
 throwing up his head at the same time, and can thus 
 wound or perhaps even transfix his antagonist. Both ani- 
 mals always kneel down, so as to guard as far as possible 
 against this maneuver. It has been recorded that one of 
 these antelopes has used his horns with effect even against 
 a lion; yet, from being forced to place his head between 
 the fore legs in order to bring the points of the horns for- 
 ward, he would generally be under a great disadvantage 
 when attacked by any other animal. It is, therefore, not 
 probable that the horns have been modified into their 
 present great length and peculiar position as a protection 
 against beasts of prey. We can, however, see that as soon 
 as some ancient male progenitor of the Oryx acquired mod- 
 erately long horns, directed a little backward, he would be 
 compelled, in his battles with rival males, to bend his head 
 somewhat inward or downward, as is now done .by certain 
 stags; and it is not improbable that he might have acquired 
 the habit of at first occasionally and afterward of regularly 
 kneeling down. In this case it is almost certain that the 
 males which possessed the longest horns would have had a 
 great advantage over others with shorter horns; and then 
 the horns would gradually have been rendered longer 
 and longer, through sexual selection, until they acquired 
 their present extraordinary length and position. 
 
 With stags of many kinds the branches of the horns 
 offer a curious case of difficulty, for certainly a single 
 straight point would inflict a much more serious wound 
 than several diverging ones. In Sir Philip Egerton's 
 museum there is a horn of the red deer ( Cervus elaphus) 
 thirty inches in length with " not fewer than fifteen snags 
 or branches;" and at Moritzburg there is still preserve^ a 
 pair of antlers of a red deer, shot in 1699 by Frederick I,
 
 582 THE DESCENT OF MAN. 
 
 one of which bears the astonishing number of thirty-three 
 branches and the other twenty-seven, making altogether 
 sixty branches. Richardson figures a pair of antlers of 
 the wild reindeer with twenty-nine points.* From the 
 manner in which the horns are branched, and more espe- 
 cially from deer being known occasionally to fight together 
 by kicking with their fore feet,f M. Bailly actually comes 
 to the conclusion that their horns are more injurious than 
 useful to them. But this author overlooks the pitched 
 battles between rival males. As I felt much perplexed about 
 the use or advantage of the branches I applied to Mr. 
 McNeill, of Colonsay, who has long and carefully observed 
 the habits of the red deer, and he informs me that he has 
 never seen some of the branches brought into use, but that 
 the brow antlers from inclining downward are a great pro- 
 tection to the forehead, and their points are likewise used 
 in attack. Sir Philip Egerton also informs me both as to 
 red deer and fallow deer that in fighting they suddenly 
 dash together, and, getting their horns fixed against each 
 other's bodies, a desperate struggle ensues. When one is 
 at last forced to yield and turn round the victor endeavors 
 to plunge his brow antlers into his defeated foe. It thus 
 appears that the upper branches are used chiefly or exclu- 
 sively for pushing and fencing. Nevertheless, in some 
 species the upper branches are used as weapons of oifense; 
 when a man was attacked by a wapiti deer (Cervus cana- 
 densis) in Judge Caton's park in Ottawa and several men 
 tried to rescue him the stag " never raised his head from 
 the ground; in fact, he kept his face almost flat on the 
 ground, with his nose nearly between his fore feet, except 
 when he rolled his head to one side to take a new observa- 
 tion preparatory to a plunge." *a this position the ends 
 of the horns were directed against his adversaries. " In 
 rolling his head he necessarily raised it somewhat, because 
 
 *On the horns of the red deer, Owen, "British Fossil Mammals," 
 1846, p. 478; Richardson on the horns of the reindeer, "Fauna Bor. 
 Americana," 1829, p. 240. I am indebted to Prof. Victor Carus for 
 the Moritzburg case. 
 
 fHon. J. D. Caton ("Ottawa Acad. of Nat. Science," May, 1868, 
 p. 9) says that the American deer fight with their fore feet, after 
 "the question of superiority has been once settled and acknowledged 
 in J " *> herd," Bailly "Sur 1'usage des Comes," " Annales des Sc. 
 >V f " " turn, ii, 1824, p. 371. 

 
 MAMMALS. 583 
 
 his antlers were so long that he could not roll his head 
 without raising them on one side, while on the other they 
 touched the ground. " The stag by this procedure gradu- 
 ally drove the party of rescuers backward to a distance 
 
 Fig. 64. Strepsloeros Kudu (from Sir Andrew Smith's " Zoology of 
 South Africa"). 
 
 of one hundred and fifty or two hundred feet, and tho 
 attacked man was killed.* 
 
 * See a most interesting account in the appendix to IIou, J. D. 
 Caton's paper, as above Quoted.
 
 584 THE DESCENT OF MAN. 
 
 Although the horns of stags are efficient weapons, there 
 can, I think, be no doubt that a single point would 
 have been much more dangerous than a branched antler; 
 and Judge Caton, who has had large experience with deer, 
 fully concurs in this conclusion. Nor do the branching 
 horns, though highly important as a means of defense 
 against rival stags, appear perfectly well adapted for this 
 purpose, as they are liable to become interlocked. The sus- 
 picion has, therefore, crossed my mind that they may serve 
 in part as ornaments. That the branched antlers of stags 
 as well as the elegant lyrated horns of certain antelopes, 
 with their graceful double curvature (fig. 64), are orna- 
 mental in our eyes, no one will dispute. If, then, the 
 horns, like the splendid accou term cuts of the knights of 
 old, add to the noble appearance of stags and antelopes, 
 they may have been modified partly for this purpose, though 
 mainly for actual service in battle; but I have no evidence 
 in favor of this belief. 
 
 An interesting case has lately been published, from which 
 it appears that the horns of a deer in one district in 
 the United States are now being modified through sexual 
 and natural selection. A writer in an excellent American 
 journal * says that he has hunted for the last twenty-one 
 years in the Adirondacks, where the Cervus virginianus 
 abounds. About fourteen years ago he first heard of spike- 
 liorn lucks. These became from year to year more 
 common; about five years ago he shot one, and afterward, 
 another, and now they are frequently killed. " The spike- 
 horn differs greatly from the common antler of the C. vir- 
 ginianus. It consists of a single spike, more slender than 
 the antler, and scarcely half so long, projecting forward 
 from the brow and terminating in a very sharp point. It 
 gives a considerable advantage to its possessor over the 
 common buck. Besides enabling him to run more swiftly 
 through the thick woods and underbrush (every hunter 
 knows that does and yearling bucks run much more rapidly 
 than the large bucks when armed with their cumbrous 
 antlers), the spike-horn is a more effective weapon than the 
 common antler. With this advantage the spike - horn 
 bucks are gaining upon the common bucks, and may, in 
 time, entirely supersede them in the Adirondacks. TJn- 
 
 " The American Naturali*W" Dec., 1869, p. 553.
 
 MAMMALS. 585 
 
 doubtedly, the first spike-horn buck was merely an acci- 
 dental freak of nature. But his spike-horns gave him an 
 advantage, and enabled him to propagate his peculiarity. 
 His descendants, having a like advantage, have propagated 
 the peculiarity in a constantly increasing ratio, till they are 
 slowly crowding the antlered deer from the region they 
 inhabit." A critic has well objected to this account by 
 asking, why, if the simple horns are now so advantageous, 
 were the branched antlers of the parent-form ever devel- 
 oped? To this I can only answer by remarking that a new 
 mode of attack with new weapons might be a great advant- 
 age, as shown by the case of the Ovis cycloceros, who thus 
 conquered a domestic ram famous for his fighting power. 
 Though the branched antlers of a stag are well adapted for 
 fighting with his rivals, and, though it might be an 
 advantage to the prong-horned variety slowly to acquire 
 long and branched horns, if he had to fight only with 
 others of the same kind, yet it by no means follows that 
 branched horns would be the best fitted for conquering a 
 foe differently armed. In the foregoing case of the Oryx 
 leucoryx it is almost certain that the victory would rest 
 with an antelope having short horns, and who, therefore, 
 did not need to kneel down, though an oryx might profit 
 by having still longer horns if he fought only with his 
 proper rivals. 
 
 Male quadrupeds, which are furnished with tusks, use 
 them in various ways, as in the case of horns. The boar 
 strikes laterally and upward; the musk-deer downward 
 with serious effect.* The walrus, though having so short 
 a neck and so unwieldly a body, ' ' can strike either upward 
 or downward or sideways with equal dexterity."! I was 
 informed by the late Dr. Falconer, that the Indian elephant 
 fights in a different manner according to the position and 
 curvature of his tusks. When they are directed forward 
 and upward he is able to fling a tiger to a great distance 
 it is said to even thirty feet; when they are short and 
 turned downward he endeavors suddenly to pin the tiger to 
 the ground, and, in consequence, is dangerous to the rider, 
 who is Jiable to be jerked off the howdah.J 
 
 * Pallas, "SpicilegiaZoologica," fasc. xiii, 1779, p. 18. 
 
 f Lament, " Seasons with the Sea-Horses," 1861, p. 141. 
 
 j See also Corse (" Philosoph. Transact.," 1799, p. 212) on the
 
 586 THE DESCENT OF MAN. 
 
 Very few male quadrupeds possess weapons of two dis- 
 tinct kinds specially adapted for fighting with rival males. 
 The male muntjac-deer (Cervulus), however, offers an ex- 
 ception, as he is provided with horns, and exserted canine 
 teeth. But we may infer from what follows that one form 
 of weapon has often been replaced in the course of ages by 
 another. With ruminants the development of horns gen- 
 erally stands in an inverse relation with that of even mod- 
 erately developed canine teeth. Thus camels, guanacoes, 
 chevrotains and musk-deer are hornless, and they have 
 efficient canines; these teeth being " always of smaller size 
 in the females than in the males. " The Camelidge have, 
 in addition to their true canines, a pair of canine-shaped in- 
 cisors in their upper jaws.* Male deer and antelopes, on 
 the other hand, possess horns, and they rarely have canine 
 teeth; and these, when present, are always of small size, so 
 that it is doubtful whether they are of any service in their 
 battles. In Antilope montana they exist only as rudiments 
 in the young male, disappearing as he grows old; and they 
 are absent in the female at all ages; but the females of cer- 
 tain other antelopes and of certain deer have been known 
 occasionally to exhibit rudiments of these teeth, f Stallions 
 have small canine teeth, which are either quite absent or 
 rudimentary in the mare; but they do not appear to be used 
 in fighting, for stallions bite with their incisors, and do 
 not open their mouths wide like camels and guanacoes. 
 Whenever the adult male possesses canines, now inefficient, 
 while the female has either none or mere rudiments, we 
 may conclude that the early male progenitor of the species 
 was provided with efficient canines, which have been par- 
 tially transferred to the females. The reduction of these 
 teeth in the males seems to have followed from some change 
 
 manner in which the short-tusked Mooknah variety attacks other 
 elephants. 
 
 *Owen, "Anatomy of Vertebrates," vol. iii, p. 349. 
 
 fSee Riippell (in " Proc Zoolog. Soc.," Jan. 12, 1836, p. 3) on the 
 canines in deer and antelopes, with a note by Mr. Martin on a female 
 American deer. See also Falconer (" Palaeont. Memoirs and Notes," 
 vol. i, 1868, p, 576) on canines in an adult female deer. In old males 
 of the musk-deer the canines (Phallas, " Spic. Zoolog.," fasc. xiii, 
 1779, p. 18) sometimes grow to the length of three inches, while in 
 old females a rudiment projects scarcely half an inch above the 
 gums.
 
 MAXXAL8. 58? 
 
 in their manner of fighting, often (but not in the horse) 
 caused by the development of new weapons. 
 
 Tusks and horns are manifestly of high importance to 
 their possessors, for their development consumes much 
 organized matter. A single tusk of the Asiatic elephant 
 one of the extinct woolly species and of the African ele- 
 phant have been known to weigh respectively one hundred 
 and fifty, one hundred and sixty and one hundred and 
 eighty pounds; and even greater weights have been given 
 by some authors.* With deer, in which the horns are peri- 
 odically renewed, the drain on the constitution must be 
 greater; the horns, for instance, of the moose weigh from 
 fifty to sixty pounds, and those of the extinct Irish elk 
 from sixty to seventy pounds the skull of the latter 
 weighing on an average only five pounds and a quarter. 
 Although the horns are not periodically renewed in sheep, 
 yet their development, in the opinion of many agricultur- 
 ists, entails a sensible loss to the breeder. Stags, more- 
 over, in escaping from beasts of prey are loaded with an 
 additional weight for the race, and are greatly retarded in 
 passing through a woody country. The moose, for in- 
 stance, with horns extending five and a half feet from tip 
 to tip, although so skillful in their use that he will not 
 touch or break a twig when walking quietly, cannot act so 
 dexterously while rushing away from a pack of wolves. 
 " During his progress he holds his nose up so as to lay the 
 horns horizontally back; and in this attitude cannot see 
 the ground distinctly. "\ The tips of the horns of the 
 great Irish elk were actually eight feet apart! While the 
 horns are covered with velvet, which lasts with red deer 
 for about twelve weeks, they are extremely sensitive to a 
 blow; so that in Germany the stags at this time somewhat 
 'change their habits, and, avoiding dense forests, frequent 
 young woods and low thickets. J These facts remind us 
 that male birds have acquired ornamental plumes at the 
 
 * Emerson Tennent, "Ceylon," 1859, vol. ii, p. 275; Owen, 
 -"British Fossil Mammals," 1846, p. 245. 
 
 f Richardson, "Fauna Bor. Americana," on the moose, Alcespal- 
 mata, pp. 236, 237; on the expanse of the horns, " Land and Water," 
 1869, p. 143. See also Owen, "British Fossil Mammals," on the 
 Irish elk, pp. 447, 455. 
 
 $ " Forest Creatures," by C. Boner, 1861, p. 60.
 
 588 TEE DESCENT OF MAN. 
 
 cost of retarded flight, and other ornaments at the cost of 
 gome loss of power in their battles with rival males. 
 
 With mammals, when, as is often the case, the sexes 
 differ in size, the males are almost always larger and 
 stronger. I am informed by Mr. Gould that this holds 
 good in a marked manner with the marsupials of Aus- 
 tralia, the males of which appear to continue growing 
 until an unusually late age. But the most extraordinay, 
 case is that of one of the seals (Callorliinus ursimts) 
 a full-grown female weighing less than one-sixth of a full- 
 grown male.* Dr. Gill remarks that it is with the polyg- 
 amous seals, the males of which are well known to fight 
 savagely together, that the sexes differ much in size; the 
 monogamous species differing but little. Whales also 
 afford evidence of the relation existing between the pug- 
 nacity of the males and their large size compared with that 
 of the females; the males of the right-whales do not fight 
 together, and they are not larger, tiut rather smaller, than 
 their females; on the other hand, male sperm-whales fight 
 much together, and their bodies are "often found scarred 
 with the imprint of their rival's teeth," and they are 
 double the size of the females. The greater strength of 
 the male, as Hunter long ago remarked, f is invariably dis- 
 played in those parts of the body which are brought into 
 action in fighting with rival males for instance, in the 
 massive neck of the bull. Male quadrupeds are also more 
 courageous and pugnacious than the females. There can be 
 little doubt that these characters have been gained, partly 
 through sexual selection, owing to a long series of victo- 
 ries, by the stronger and more courageous males over the 
 weaker, and partly through the inherited effects of use. 
 It is probable that the successive variations in strength, 
 size, and courage, whether due to mere variability or to the 
 effects of use, by the accumulation of which male quadru- 
 peds have acquired these characteristic qualities, occurred 
 rather late in life, and were consequently to a large extent 
 limited in their transmission to the same sex. 
 
 *See the very interesting paper by Mr. J. A. Allen in "Bull. Mus. 
 Comp. Zoolog. of Cambridge, United States," vol. ii, No. 1, p. 82. 
 The weights were ascertained by a careful observer, Capt, Bryant. 
 Dr. Gill in " The American Naturalist," Jan., 1871; Prof. Shaler on 
 the relative size of the sexes of whales, ''American Naturalist," 
 Jan. 1873. 
 
 f " Animal Economy," p. 45
 
 MAMMALS. 589 
 
 From these considerations I was anxious to obtain infor- 
 mation as to the Scotch deer-hound, the sexes of which 
 
 differ more in size than those of any other breed (though 
 blood-hounds differ considerably), or than in any wild 
 canine species known to me. Accordingly, I applied to 
 Mr. Cupples, well known for his success with this breed, 
 who has weighed and measured many of his own dogs, and 
 who has with great kindness collected for me the following 
 facts from various sources. Fine male dogs, measured at 
 the shoulder, range from 28 inches, which is low, to 33 or 
 even 34 inches in height ; and in weight from 80 pounds, 
 which is light, to 120 pounds, or even more. The 
 females range in height from 23 to 27, or even 
 to 28 inches ; and in weight from 50 to 70, 
 or even 80 pounds.* Mr. Cupples concludes that from 
 95 to 100 pounds for the male, and 70 for the female, 
 would be a safe average; but there is reason to believe that 
 formerly both sexes attained a greater weight. Mr. Cup- 
 pies has weighed puppies when a fortnight old; in one 
 litter the average Aveight of four males exceeded that of 
 two females by six and a half ounces; in another litter the 
 average weight of four males exceeded that of one female 
 by less than one ounce; the same males when three weeks 
 old exceeded the female by seven and a half ounces, and 
 at the age of six weeks by nearly fourteen ounces. Mr. 
 Wright, of Yeldersley House, in a letter to Mr. Cupples 
 says: "I have taken notes on the sizes and weights of 
 puppies of many litters, and, as far as my experience goes, 
 dog puppies, as a rule, differ very little from bitches till 
 they arrive at about five or six months old; and then the 
 dogs begin to increase, gaining upon the bitches both in 
 weight and size. At birth and for several weeks afterward 
 a bitch-puppy will occasionally be larger than any of the 
 dogs, but they are invariably beaten by them later." Mr. 
 McNeill, of Colonsay, concludes that " the males do not 
 attain their full growth till over two years old, though the 
 females attain it sooner." According to Mr. Cupples' 
 
 * See also Richardson's " Manual on the Dog," p. 59. Much valu- 
 able information on the Scottish deer-hound is given by Mr. Mc- 
 Neill, who first called attention to the inequality in size between the 
 sexes, in Scrope's " Art of Deer Stalking." I hope that Mr. Cupples 
 will keep to his intention of publishing a full account and history of 
 this famous breed.
 
 590 THE DESCENT OF MAN. 
 
 experience, male dogs go on growing in stature till they 
 are from twelve to eighteen months old, and in weight till 
 from eighteen to twenty-four months old; while the females 
 cease increasing in stature at the age of from nine to four- 
 teen or fifteen months, and in weight at the age of from 
 twelve to fifteen months. From these various statements 
 it is clear that the full difference in size between the male 
 and female Scotch deer-hound is not acquired until rather 
 late in life. The males almost exclusively are used for 
 
 coursing, for, as Mr. Me- 
 Neill informs me, the fe- 
 males have not sufficient 
 strength and Aveight to 
 pull down a full-grown 
 deer. From the names 
 used in old legends it 
 appears, as I hear from 
 Mr. Cupples, that at a 
 very ancient period the 
 males were the most 
 celebrated, the females 
 being mentioned only as 
 the mothers of famous 
 
 Pig. 05. Head of common wild boar, m *,.-. Ttnnna. Aiim-nn 
 
 prime of life (from Brehm). dogS. Hence, during 
 
 many generations it is the 
 
 male which has been chiefly tested for strength, size, speed 
 and courage, and the best will have been bred from. As, 
 however, the males do not attain their full dimensions until 
 rather late in life they will have tended, in accordance 
 with the law often indicated, to transmit their characters 
 to their male off spring alone; and thus the great inequality 
 in size between the sexes of the Scotch deer-hound may 
 probably be accounted for. 
 
 The males of some few quadrupeds possess organs or 
 parts developed solely as a means of defense against the 
 attacks of other males. Some kinds of deer use, as we 
 have seen, the upper branches of their horns chiefly or 
 exclusively for defending themselves; and the Oryx ante- 
 lope, as I am informed by Mr. Bartlett, fences most skill- 
 fully with his long, gently curved horns ; but these are 
 likewise used as organs o"f offense. The same observer 
 remarks that rhinoceroses in fighting parry each other's 
 sidelong blows with their horns, which clatter loudly
 
 MAMMALS. 591 
 
 together, as do the tusks of boars. Although wild boars 
 fight desperately, they seldom, according to Brehm, receive 
 fatal wounds, as the blows fall on each other's tusks, or on 
 the layer of gristly skin covering the shoulder, called by 
 the German hunters the shield; and here we have a part 
 specially modified for defense. With boars in the prime 
 of life (fig. 65) the tusks in the lower jaw are used for 
 fighting, but they become in old age, as Brehm states, BO 
 
 Fig. 66, Skull of the Babirusa Pig (from Wallace's " Malay Archipelago"). 
 
 much curved inward and upward over the snout that they 
 can no longer be used in this way. They may, however, 
 still serve, and even more effectively, as a means of defense. 
 In compensation for the loss of the lower tusks as weapons 
 of offense those in the upper jaw, which always project a 
 little laterally, increase in old age so much in length and 
 curve so much upward that they can be used for attack. 
 Nevertheless, an old boar is not so dangerous to man as 
 one at the age of six or seven years.* 
 
 ~~~* Brehm, " Thierleben," B. ii, ss. 729-733.
 
 592 fHE DESCENT OF MAN. 
 
 In the full-grown male Babirusa pig of Celebes (fig. 66), 
 the lower tusks are formidable weapons, like those of the 
 European boar in the prime of life, while the upper tusks 
 are so long and have their points so much curled inward, 
 sometimes even touching the forehead, that they are utterly 
 useless as weapons of attack. They more nearly resemble 
 horns than teeth, and are so manifestly useless as teeth that 
 the animal was formerly supposed to rest his head by hook- 
 ing them on to a branch! Their convex surfaces, however, 
 if the head were held a little laterally, would serve as an 
 
 Fig. 67. Head of female Ethiopian wart-hog, from " Proo. Zool. Soo." 1869, 
 showing the same characters as the male, though on a reduced scale. 
 
 N. B. When the engraving was first made I was under the impression that it 
 represented the male. 
 
 excellent guard; and hence, perhaps, it is that in old 
 animals they "are generally broken off, as if by fighting."* 
 Here, then, we have the curious case of the upper tusks of 
 the Babirusa regularly assuming during the prime of life a 
 structure which apparently renders them fitted only for 
 defense ; Avhile in the European boar the lower tusks 
 assume in a less degree and only during old age nearly the 
 same form, and then serve in like manner solely for 
 defense. 
 
 In the wart-hog ( Phacochoerus cethiopicus] (fig. 67) the 
 
 * See Mr. Wallace's interesting account of this animal, " The 
 Malay Archipelago," 1869, vol. i, p. 435,
 
 MAMMALS. 593 
 
 tusks in the upper jaw of the male curve upward during 
 the prime of life, and from being pointed serve as formid- 
 able weapons. The tusks in the lower jaw are sharper 
 than those in the upper, but from their shortness it seems 
 hardly possible that they can be used as weapons of attack. 
 They must, however, greatly strengthen those in the upper 
 jaw, from being ground so as to fit closely against their 
 bases. Neither the upper nor the lower tusks appear to,f 
 have been specially modified to act as guards, though no 
 doubt they are to a certain extent used for this purpose. 
 But the wart-hog is not destitute of other special means 
 of protection, for it has on each side of the face, 
 beneath the eyes, a rather stiff, yet flexible cartilaginous 
 oblong pad (see fig. 67), which projects two or three inches 
 outward; and it appeared to Mr. Bartlett and myself, 
 when viewing the living animal, that these pads, when 
 struck from beneath by the tusks of an opponent, would 
 be turned upward, and would thus admirably protect 
 the somewhat prominent eyes. I may add, on the 
 authority of Mr. Bartlett, that these boars when fight- 
 ing stand directly face to face. 
 
 Lastly, the African river-hog (PotomocJioerus penicil- 
 latus) has a hard cartilaginous knob on each side of the 
 face beneath the eyes, which answers to the flexible pad 
 of the wart-hog; it has also two bony prominences on the 
 upper jaw above the nostrils. A boar of this species in 
 the Zoological Gardens recently broke into the cage of 
 the wart-hog. They fought all night long, and were 
 found in the morning much exhausted, but not seriously 
 wounded. It is a significant fact, as showing the purposes 
 of the above described projections and excrescences, that 
 these were covered with blood, and were scored and abraded 
 in an extraordinary manner. 
 
 Although the males of so many members of the pig 
 family are provided with weapons, and, as we have just seen, 
 with means of defense, these weapons seem to have been 
 acquired within a rather late geological period. Dr. For- 
 syth Major specifies* several miocene species, in none of 
 which do the tusks appear to have been largely developed 
 in the males; and Prof. Eiitimeyer was formerly struck 
 with this same fact. 
 
 *" Atti della Soc. Italiana di Sc. Nat." 1873, vol. xv, fasc. iv.
 
 594 THE DESCENT OF MAN. 
 
 The mane of the lion forms a good defense against the 
 attacks of rival lions, the one danger to which he is liable; 
 for the males, as Sir A. Smith informs me, engage in ter- 
 rible battles, and a young lion dares not approach an 
 old one. In 1857 a tiger at Bromwich broke into the cage 
 of a lion and a fearful scene ensued; "the lion's inane 
 saved his neck and head from being much injured, but the 
 tiger at last succeeded in ripping up his belly, and in a few 
 minutes he was dead/' * The broad ruff round the throat 
 and chin of the Canadian lynx (Felis canadensis) is much 
 longer in the male than in the female; but whether it 
 serves as a defense I do not know. Male seals are well 
 known to fight desperately together, and the males of cer- 
 tain kinds ( Otaria jubata) f have great manes, while the 
 females have small ones or none. The male baboon of 
 the Cape of Good Hope (Cynoceplialus porcarius) has a 
 much longer mane and larger canine teeth than the female; 
 and the mane probably serves as a protection, for, on 
 asking the keepers in the Zoological Gardens, without 
 giving them any clew to my object, whether any of the 
 monkeys especially attacked each other by the nape of the 
 neck, I was answered that this was not the case, except 
 with the above baboon. In the Hamadryas baboon, 
 Ehrenberg compares the mane of the adult male to that of 
 a young lion, while in the young of both sexes and in the 
 female the mane is almost absent. 
 
 It appeared to me probable that the immense woolly 
 mane of the male American bison, which reaches almost to 
 the ground, and is much more developed in the males than 
 in the females, served as a protection to them in their ter- 
 rible battles; but an experienced hunter told Judge Caton 
 that he had never observed anything which favored this 
 belief. The stallion has a thicker and fuller mane than 
 the mare; and I have made particular inquiries of two great 
 trainers and breeders, who have had charge of many 
 entire horses, and am assured that they . " invariably 
 
 * " The Times," Nov. 10, 1857. In regard to the Canada lynx, see 
 Audubon and Bachman, " Quadrupeds of North America," 1846, p. 
 139. 
 
 fDr. Murie, on Otaria, "Proc. Zoolog. Soc.," 1869, p. 109. Mr. 
 J. A. Allen, in the paper above quoted (p. 75), doubts whether the 
 hair, which is longer on the neck in the male than in the female, 
 deserves to be called a inane..
 
 MAMMALS. 595 
 
 endeavor to seize one another by the neck." It does not, 
 however, follow from the foregoing statements, that when 
 the hair on the neck serves as a defense, that it was origi- 
 nally developed for this purpose, though this is probable in 
 gome cases, as in that of the lion. I am informed by Mr. 
 MeNTeill that the long hairs on the throat of the stag 
 ( Cervus elaplms) serve as a great protection to him when 
 hunted, for the dogs generally endeavor to seize him by the 
 throat; but it is not probable that these hairs were specially 
 developed for this purpose; otherwise the young and the 
 females would have been equally protected. 
 
 Choice in Pairing by Either Sex of Quadrupeds. Before 
 describing, in the next chapter, the differences between the 
 sexes in voice, odors emitted and ornaments, it will be con- 
 venient here to consider whether the sexes exert any choice 
 in their unions. Does the female prefer any particular 
 male, either before or after the males may have fought 
 together for supremacy; or does the male, when not a 
 polygamist, select any particular female? The general 
 impression among breeders seems to be that the male accepts 
 any female; and this, owing to his eagerness, is, in most 
 cases, probably the truth. Whether the female, as a 
 general rule, indifferently accepts any male is much more 
 doubtful. In the fourteenth chapter, on birds, a consider- 
 able body of direct and indirect evidence was advanced 
 showing that the female selects her partner; and it would 
 be a strange anomaly if female quadrupeds, which stand 
 higher in the scale and have higher mental powers, did not 
 generally, or at least often, exert some choice. The female 
 could in most cases escape, if wooed by a male that did not 
 please or excite her; and when pursued by several males, 
 as commonly occurs, she would often have the opportunity, 
 while they were fighting together, of escaping with some 
 one male, or at least of temporarily pairing with him. 
 This latter contingency has often been observed in Scot- 
 land with female red deer, as I am informed by Sir Philip 
 Egerton and others.* 
 
 * Mr. Boner, in his excellent description of the habits of the red- 
 deer in Germany (" Forest Creatures," 1861, p. 81) says, "while the 
 stag is defending his rights against one intruder, another invades the 
 sanctuary of his harern, and carries off trophy after trophy." 
 Exactly the same thing occurs with seals. See Mr. J. A. Allen, ibid, 
 p. 100.
 
 596 THE DESCENT OF MAN. 
 
 It is scarcely possible that much should be known about 
 female quadrupeds iii a state of nature making any choice 
 in their marriage unions. The following curious details 
 on the courtship of one of the eared seals (CaUorJiinus 
 ur sinus) are given* on the authority of Capt. feryant, who 
 had ample opportunities for observation. He says: " Many 
 of the females on their arrival at the island where they 
 breed appear desirous of returning to some particular male, 
 and frequently climb the outlying rocks to overlook the 
 rookeries, calling out and listening as if for a familiar 
 voice. Then changing to another place they do the same 
 again ... As soon as a female reaches the shore, the 
 nearest male goes down to meet her, making, meanwhile, 
 a noise like the clucking of a hen to her chickens. He 
 bows to her and coaxes her until he gets between her and 
 the water so that she cannot escape him. Then his man- 
 ner changes and with a harsh growl he drives her to a place 
 in his harem. This continues until the lower row of 
 harems is nearly full. Then the males higher up select 
 the time when their more fortunate neighbors are off their 
 guard to steal their wives. This they do by taking them in 
 their mouths and lifting them over the heads of the other 
 females and carefully placing them in their own harem, 
 carrying them as cats do their kittens. Those still higher 
 up pursue the same method until the whole space is occu- 
 pied. Frequently a struggle ensues between two males for 
 the possession of the same female, and both seizing her at 
 once pull her in two or terribly lacerate her with their 
 teeth. When the space is all filled, the old male walks 
 around complacently reviewing his family, scolding those 
 who crowd or disturb the others and fiercely driving off all 
 intruders. This surveillance always keeps him actively 
 occupied." 
 
 As so little is known about the courtship of anima's in a 
 state of nature, I have endeavored to discover how far our 
 domesticated quadrupeds evince any choice in their unions. 
 Dogs offer the best opportunity for observation, as they 
 are carefully attended to and well understood. Many 
 breeders have expressed a strong opinion on this head. 
 Thus, Mr. Mayhew remarks: "The females are able to 
 
 *Mr. J. A. Allen in "Bull. Mus. Comp. Zoolog. of Cambridge. 
 United States," vol. ii, No. 1, p. 99.
 
 MAMMALS. 597 
 
 bestow their affections ; and tender recollections are as 
 potent over them as they are known to be in other cases, 
 where higher animals are concerned. Bitches are not 
 always prudent in their loves, but are apt to fling them- 
 selves away on curs of low degree. If reared with a com- 
 panion of vulgar appearance, there often springs up between 
 the pair a devotion which no time can afterward subdue. 
 The passion, for such it really is, becomes of a more than 
 romantic endurance." Mr. Mayhew, who attended chiefly 
 to the smaller breeds, is convinced that the females are 
 strongly attracted by males of a large size.* The well- 
 known veterinary Elaine statesf that his own female pug 
 became so attached to a spaniel, and a female setter to a 
 cur, that in neither case would they pair with a dog of their 
 own breed until several weeks had elapsed. Two similar 
 and trustworthy accounts have been given me in regard to 
 a female retriever and a spaniel, both of which became 
 enamored with terrier dogs. 
 
 Mr. Cupples informs me that he can personally vouch 
 for the accuracy of the following more remarkable case, in 
 which a valuable and wonderfully intelligent female terrier 
 loved a retriever belonging to a neighbor to such a degree 
 that she had often to be dragged away from him. After 
 their permanent separation, although repeatedly showing 
 milk in her teats, she would never acknowledge the court- 
 ship of any other dog, and, to the regret of her owner, never 
 bore puppies. Mr. Cupples also states that, in 1868, a 
 female deerhound in his kennel thrice produced puppies, 
 and on each occasion showed a marked preference for one 
 of the largest and handsomest, but not the most eager, of 
 four deerhonnds living with her, all in the prime of life. 
 Mr. Cupples has observed that the female generally favors 
 a dog whom she has associated with and knows; her shy- 
 ness and timidity at first incline her against a strange dog. 
 The male, on the contrary, seems rather inclined toward 
 strange females. It appears to be rare when the male 
 refuses any particular female, but Mr. Wright, of Yelders- 
 ley- House, a great breeder of dogs, informs me that he has 
 known some instances; he cites the case of one of his own 
 
 *"Dogs: Their Management," by E. Mayhew, M. R. C. V. 8., 
 2d edit., 1864, pp. 187-192, 
 
 f Quoted by Alex, WaOk% "On Intermarriage," 1838, p, 270; see 
 also p. 244.
 
 598 THE DESCENT OF MAN. 
 
 deerhounds who would not take any notice of a particular 
 female mastiff, so that another deerhound had to he 
 employed. It would be superfluous to give, as I could, 
 other instances, and I will only add that Mr. Barr, who 
 has carefully bred many bloodhounds, states that in almost 
 every instance particular individuals of opposite sexes show 
 a decided preference for each other. Finally, Mr. Cup- 
 pies, after attending to this subject for another year, lias 
 written to me: "I have had full confirmation of my former 
 statement that dogs in breeding form decided preferences 
 for each other, being often influenced by size, bright color 
 and individual characters, as well as by the degree of their 
 previous familiarity." 
 
 In regard to horses, Mr. Blenkiron, the greatest breeder 
 of race-horses in the world, informs me that stallions are 
 so frequently capricious in their choice, rejecting one mare 
 and without any apparent cause taking to another, that 
 various artifices have to be habitually used. The famous 
 Monarque, for instance, would never consciously look at the 
 dam of G-ladiateur, and a trick had to be practiced. We 
 can partly see the reason why valuable race-horse stallions, 
 which are in such demand as to be exhausted, should be so 
 particular in their choice. Mr. Blenkiron has never known 
 a mare reject a horse ; but this has occurred in Mr. 
 Wright's stable, so that the mare had to be cheated. 
 Prosper Lucas* quotes various statements from French 
 authorities, and remarks: " On voit des 6talons qui s'6pren- 
 nent d'une jument, et negligent toutes les autres." He 
 gives, on the authority of Baelen, similar facts in regard to 
 bulls; and Mr. H. Reeks assures me that a famous short- 
 horn bull, belonging to his father, "invariably refused to 
 be matched with a black cow." Hoffberg, in describing 
 the domesticated reindeer of Lapland, says: "Foeminae 
 majores et fortiores mares prse caeteris admittunt, ad eos 
 confugiunt, a junioribus agitatae, qui hos in fugam con- 
 jiciunt." f A clergyman, who has bred many pigs, asserts 
 that sows often reject one boar and immediately accept 
 another. 
 
 From these facts there can be no doubt that, with most 
 of our domesticated quadrupeds, strong individual antipa- 
 
 * " TraiiS de l'H6r6d. Nat.," torn, ii, 1850, p. 296. 
 f " Amcenitates Acad.," vol. iv, 1788, p. 160.
 
 MAMMALS. 599 
 
 thies and preferences are frequently exhibited, and much 
 more commonly by the female than by the male. This 
 being the case, it is improbable that the unions of quadru- 
 peds in a state of nature should be left to mere chance. It 
 is much more probable that the females are allured or 
 excited by particular males who possess certain characters 
 in a higher degree than other males; but what these char- 
 acters are we can seldom or never discover with certainty.
 
 600 THE DESCENT OF MAN. 
 
 CHAPTER XVIII. 
 
 SECONDARY SEXUAL CHARACTERS OF MAMMALS 
 
 continued. 
 
 Voice Remarkable sexual peculiarities in seals Odor Develop- 
 ment of tlie liair Color of the hair and skin Anomalous case 
 of the female being more ornamented than the male Color and 
 ornaments due to sexual selection Color acquired for the sake 
 of protection Color, though common to both sexes, often due to 
 sexual selection On the disappearance of spots and stripes in 
 adult quadrupeds On the colors and ornaments of the quad- 
 rumana Summary. 
 
 QUADRUPEDS use their voices for various purposes, as a 
 signal of danger, as a call from one member of a troop to 
 another, or from the mother to her lost offspring, or from 
 the latter for protection to their mother; but such uses 
 need not here be considered. We are concerned only with 
 the difference between the voice* of the sexes; for instance, 
 between that of the lion and lioness, or of the bull and 
 cow. Almost all male animals use their voices much more 
 during the rutting-season than at any other time ; and 
 some, as the giraffe and porcupine,* are said to be com- 
 pletely mute excepting at this season. As the throats (i.e. 
 of the larynx and thyroid bodies f) of stags periodically 
 become enlarged at the beginning of the breeding-season, 
 it might be thought that their powerful voices must be 
 somehow of high importance to them; but this is very 
 doubtful. From information given to me by two experi- 
 enced observers, Mr. McNeill and Sir P. Egerton, it seems 
 that young, stags under three years old do not roar or 
 bellow; and that the old ones begin bellowing at the com- 
 mencement of the breeding-season, at first only occasionally 
 and moderately, while they restlessly wander about in 
 search of the females. Their battles are prefaced by loud 
 
 *Owen, "Anatomy of Vertebrates," vol. iii, p. 686. 
 f Ibid, p. 595.
 
 MAMMALS. 601 
 
 and prolonged bellowing, but during the actual conflict 
 they are silent. Animals of all kinds which habitually use 
 their voices utter various noises under any strong emotion, 
 as when enraged and preparing to fight ; but this may 
 merely be the result of nervous excitement, which leads to 
 the spasmodic contraction of almost all the muscles of the 
 body, as when a man grinds his teeth and clenches his fists 
 in rage or agony. No doubt stags challenge each other to 
 mortal combat by bellowing; but those with the more 
 powerful voices, unless at the same time the stronger, better- 
 armed and more courageous, would not gain any advantage 
 over their rivals. 
 
 It is possible that the roaring of the lion may be of 
 some service to him by striking terror into his adversary; for 
 when enraged he likewise erects his mane and thus instinct- 
 ively tries to make himself appear as terrible as possible. 
 But it can hardly be supposed that the bellowing of the 
 stag, even if it be of service to him in this way, can have 
 been important enough to have led to the periodical 
 enlargement of the throat. Some writers suggest that the 
 bellowing serves as a call to the female; but the expe- 
 rienced observers above quoted inform me that female deer 
 do not search for the male, though the males search 
 eagerly for the females, as indeed might be expected from 
 what we know of the habits of other male quadrupeds. 
 The voice of the female, on the other hand, quickly brings 
 to her one or more stags,* as is well known to the hunters 
 who in wild countries imitate her cry. If we could believe 
 that the male had the power to excite or allure the female 
 by his voice, the periodical enlargement of his vocal organs 
 would be intelligible on the principle of sexual selection, 
 together with inheritance limited to the same sex and 
 season; but we have no evidence in favor of this view. 
 As the case stands, the loud voice of the stag during the 
 breeding-season does not seem to be of any special service 
 to him, either during his courtship or battles, or in any 
 other way. But may we not believe that the frequent use 
 of the voice, under the strong excitement of love, jealousy 
 and rage, continued during many generations, may at last 
 
 *See, for instance, Maj. W. Ross King ("The Sportsman in 
 Canada," 1866, pp. 53, 131) on the habits of the moose and wild 
 reindeer.
 
 602 THE DESCENT OF MAN. 
 
 have produced an inherited effect on the vocal or$ JIB of 
 the stag as well as of other male animals ? This appears to 
 me, in our present state of knowledge, the most probable 
 view. 
 
 The voice of the adult male gorilla is tremendous, and 
 he is furnished with a laryngeal sack, as is the adult male 
 orang.* The gibbons rank among the noisiest of monkeys, 
 and the Sumatra species (Hylobates syndactylus} are also 
 furnished with an air sack; but Mr. Blyth, who has had 
 opportunities for observation, does not believe that the male 
 is noiser than the female. Hence, these latter monkeys 
 probably use their voices as a mutual call ; and this is cer- 
 tainly the case with some quadrupeds, for instance the 
 beaver, f Another gibbon, the //. agilis, is remarkable, 
 from having the power of giving a complete and correct 
 octave of musical notes, J which we may reasonably suspect 
 serves as a sexual charm; but I shall have to recur to this 
 subject in- the next chapter. The vocal organs of the 
 American Mycetes caraya are one-third larger in the male 
 than in the female, and are wonderfully powerful. These 
 monkeys in warm weather make the forests resound at 
 morning and evening with their overwhelming voices. 
 The malen begin the dreadful concert and often continue 
 it during many hours, the females sometimes joining in 
 with their less-powerful voices. An excellent observer 
 Rengger could not perceive that they were excited to 
 begin by any special cause ; he thinks that, like many 
 birds, they delight in their own music, and try to excel each 
 other. Whether most of the foregoing monkeys have 
 acquired their powerful voices in order to beat their rivals 
 and charm the females or whether the vocal organs have 
 been strengthened and enlarged through the inherited 
 effects of long-continued use without any particular good 
 being thus gained I will not pretend to say; but the 
 former view, at least in the case of the Hylobates agilis, 
 seems the most probable. 
 
 *0wen, " Anatomy of Vertebrates," vol. iii, p. 600. 
 
 f Mr. Green, in " Journal of Linn. Soc.," vol. x, Zoology, r869, p. 
 862. 
 
 $C. L. Marun. " General Introduction to the Nat. Hist, of Mamm. 
 Animals," 1841, p. 431. 
 
 " Naturgeschichte der Sftugethiere von Paraguay," 1830, BB. 
 10, 31
 
 MAMMALS. 608 
 
 I may here mention two very curious sexual peculiarities 
 occurring in seals, because they have been supposed by 
 Borne writers to affect the voice. The nose of the male 
 sea-elephant (Macrorhinus propose ideus) becomes greatly 
 elongated during the breeding-season and can then be 
 erected. In this state it is sometimes a foot in length. 
 The female is not thus provided at any period of fife. 
 The male makes a wild, hoarse, gurgling noise, which is 
 audible at a great distance and is believed to be strength- 
 ened by the proboscis; the voice of the female being differ- 
 ent. Lesson compares the erection of the proboscis with 
 the swelling of the wattles of male gallinaceous birds 
 while courting the females. In another allied kind of 
 seal, the bladder-nose (Cystopliora cristata], the head is 
 covered by a great hood or bladder. This is supported by 
 the septum of the nose, which is produced far backward 
 and rises into an internal crest seven inches in height. 
 The hood is clothed with short hair and is muscular; it 
 can be inflated until it more than equals the whole head in 
 size! The males when rutting fight furiously on the ice, 
 and their roaring " is said to be sometimes so loud as to 
 be heard four miles off." When attacked they likewise 
 roar or bellow; and whenever irritated the bladder is 
 inflated and quivers. Some naturalists believe that the 
 voice is thus strengthened, but various other uses have 
 been assigned to this extraordinary structure. Mr. R. 
 Brown thinks that it serves as a protection against acci- 
 dents of all kinds; but this is not probable, for, as I am 
 assured by Mr. Lamont, who killed six hundred of these 
 animals, the hood is rudimentary in the females and it is 
 not developed in the males during youth.* 
 
 Odor. With some animals, as with the notorious skunk 
 of America, the overwhelming odor which they emit 
 appears to serve exclusively as a defense. With shrew- 
 mice (Sorex) both sexes possess abdominal scent-glands, 
 
 ,*0n the sea- elephant, see an article by Lesson, in "Diet. Class. 
 Hist. Nat.," torn, xiii, p. 418. For the Cystophora, or Stemmatopus, 
 see Dr. Dekay "Annals of Lyceum of Nat. Hist. New York," vol. 
 i, 1824, p, 94. Pennant has also collected information from the 
 sealers on this animal. The fullest account is given by Mr. Brown, 
 in " Proc. Zoolog. Soc.," 1868, p. 436.
 
 604 THE DESCENT OF MAN, 
 
 and there can be little doubt, from the rejection of their 
 bodies by birds and beasts of prey, that the odor is pro- 
 tective; nevertheless, the glands become enlarged in the 
 males during the breeding-season. In many other quad- 
 rupeds the glands are of the same size in both sexes,* but 
 their uses are not known. In other species the glands are 
 confined to the males or are more developed than in the 
 females ; and they almost always become more active 
 during the rutting-season. At this period the glands on 
 the sides of the face of the male elephant enlarge and emit 
 a secretion having a strong musky odor. The males, and 
 rarely the females, of many kinds of bats have glands and 
 protrudable sacks situated in various parts; and it is 
 believed that these are odoriferous. 
 
 The Tank effluvium of the male goat is well known, and 
 that of certain male deer is wonderfully strong and per- 
 sistent. On the banks of the Plata I perceived the air 
 tainted with the odor of the male Cervus campestris at 
 half a mile to leeward of a herd; and a silk handkerchief, 
 in which I carried home a skin, though often used and 
 washed, retained when first unfolded traces of the odor for 
 one year and seven months. This animal does not emit 
 its strong odor until more than a year old, and if castrated 
 while young never emits it.f Besides the general odor 
 permeating the whole body of certain ruminants (for in- 
 stance, Bos moschaiiis) in the breeding-season, many deer, 
 antelopes, sheep and goats possess odoriferous glands in 
 various situations, more especially on their faces. The 
 so-called tear-sacks, or suborbital pits, come under this 
 head. These glands secrete & semi-fluid fetid matter which 
 is sometimes so copious as to stain the whole face, as I 
 have myself seen in an antelope. They are "usually 
 larger in the male than in the female, and their develop- 
 
 *As with the castoreum of the beaver, see Mr. L. H. Morgan's 
 most interesting work, "The American Beaver," 1868, p. 300. 
 Pallas (" Spic. Zoolog.," fasc. viii, 1779, p. 23) has well discussed the 
 odoriferous glands of mammals. Owen ("Anat. of Vertebrates," 
 vol. iii, p. 634) also gives an account of these glands, including those 
 of the elephant, and (p. 763) those of shrew-mice. On bats, Mr. 
 Dobson in "Proc. Zoolog. Soc.," 1873, p. 241. 
 
 fRengger, " Xaturgeschichte der Saugetmere von Paraguay," 
 1830, s. 355. This observer also gives some curious particulars ia 
 regard to the odor.
 
 MAMMALS. 605 
 
 ment is checked by castration."* According to Desmarest, 
 they are altogether absent in the female of Antilope sub- 
 gutturosa. Hence, there can be no doubt that they stand 
 in close relation with the reproductive functions. They 
 are also sometimes present, and sometimes absent, in nearly 
 allied forms. In the adult male musk deer (Mosclius mos- 
 chiferus) a naked space round the tail is bedewed with an 
 odoriferous fluid, while in the adult female, and in the 
 male until two years old, this space is covered with hair 
 and is not odoriferous. The proper musk-sack of this 
 deer is from its position necessarily confined to the male 
 and forms an additional scent-organ. It is a singular fact 
 that the matter secreted by this latter gland does not, 
 according to Pallas, change in consistence or increase in 
 quantity during the rutting - season ; nevertheless, this 
 naturalist admits that its presence is in some way con- 
 nected with the act of reproduction. He gives, however, 
 only a conjectural and unsatisfactory explanation of its 
 use. f 
 
 In most cases, when only the male emits a strong odor 
 during the breeding-season, it probably serves to excite or 
 allure the female. We must not judge on this head by our 
 own taste, for it is well known that rats are enticed by 
 certain essential oils, and cats by valerian, substances far 
 from agreeable to us; and that dogs, though they will not 
 eat carrion, sniff and roll on it. From the reasons given 
 when discussing the voice of the stag Ave may reject the 
 idea that the odor serves to bring the females from a dis- 
 tance to the males. Active and long-continued use cannot 
 here have come into play, as in the case of the vocal organs. 
 The odor emitted must be of considerable importance to 
 the male, inasmuch as large and complex glands, furnished 
 with muscles for everting the sack and for closing or open- 
 ing the orifice, have in some cases been developed. The 
 development of Jiese organs is intelligible through sexual 
 selection if the most odoriferous males are the most suc- 
 
 -*0wen; " Anatomy of Vercebrates," vol. iii, p. 632. See also Dr. 
 Murie's observations on these glands in the "Proc. Zoolog. Soc.," 
 1870, p. 340. l>osmarest, on the Antilope subgutturosa, "Mammal- 
 ogie," 1820, p. 455. 
 
 fPhallas, " Spicilegia Zoolog.," fasc. xiii, 1799, p. 24; Desmou 
 line, " Diet. Class. d'Hist. Nat.," torn, iii, p. 586.
 
 606 THE DESCENT OF MAN. 
 
 cessful in winning the females, and in leaving offspring to 
 inherit their gradually perfected glands and odors. 
 
 Development of the Hair. We have seen that male quad- 
 rupeds often have the hair on their necks and shoulders 
 much more developed than the females; and many addi- 
 tional instances could be given. This sometimes serves as 
 a defense to the male during his battles; but whether the 
 hair in most cases has been specially developed for this 
 purpose is very doubtful. We may feel almost certain that 
 this is not the case, when only a thin and narrow crest runs 
 along the back ; for a crest of this kind would afford 
 scarcely any protection, and the ridge of the back is not 
 a place likely to be injured; nevertheless such crests are 
 sometimes confined to the males, or are much more devel- 
 oped in them than in the females. Two antelopes, the 
 Tragelaplius scriptus* (see fig. 70, p. 620) and Portax picta 
 may be given as instances. When stags and the males of the 
 wild goat are enraged or terrified these crests stand erect;f 
 but t cannot be supposed that they have been developed 
 merely for the sake of exciting fear in their enemies. One 
 of the above-named antelopes, the Partax picta, has a large, 
 well-defined brush of black hair on the throat, and this is 
 much larger in the male than in the female. In the 
 Ammotragus tragelaphus of N. Africa, a member of the 
 sheep family, the fore legs are almost concealed by an 
 extraordinary growth of hair, which depends from the 
 neck and upper halves of the legs; but Mr. Bartlett does 
 not believe that this mantle is of the least use to the male, 
 in whom it is much more developed than in the female. 
 
 Male quadrupeds of many kinds differ from the females 
 in having more hair, or hair of a different character, on 
 certain parts of their faces. Thus the bull alone has curled 
 hair on the forehead. J In three closely allied sub-genera 
 of the goat family only the males possess beards, sometimes 
 of large size; in two other sub-genera both sexes have a 
 
 * Dr. Gray, " Gleanings from the Menagerie at Knowsley," pi. 28. 
 
 f Judge Caton on tlie Wapiti, "Transact. Ottawa Acad. Nat. 
 Sciences," 1868, pp. 36, 40; Blytli, "Land and Water," on Capra 
 cegagrus, 1867, p. 37. 
 
 J " Hunter's Essays and Observations," edited by Owen, 1861, vL 
 i, p. 236.
 
 MAMMALS. 
 
 607 
 
 beard, but it disappears in some of the domestic breeds of 
 the common goat; and neither sex of the Hemitragus has 
 a beard. In the ibex the beard is not developed during the 
 cummer, and it is so small at other times that it may be 
 called rudimentary.* With some monkeys the beard is 
 confined to the male, as in the orang; or is much larger in 
 
 Fig. 68. Pithecia satanas, male (from Brehm). 
 
 the male than in the female, as in the Mycetes caraya and 
 Pithecia satanas (fig. 68). So it is with the whiskers of 
 some species of Macaous,f and, as we have seen, with the 
 manes of some species of baboons. But with most kinds 
 of , monkeys the various tufts of hair about the face and 
 head are alike in both sexes. 
 
 *See Dr. Gray's "Cat. of Mammalia in British Museum," part iii, 
 1852, p. 144. 
 
 f Rengger, " Saugethiere," etc., s. 14; Desinarest. "Mammal 
 ogie," p. 86.
 
 tfOS THE DESCENT OF MAN. 
 
 The males of various members of the ox family (Bovidas), 
 and of certain antelopes, are furnished with a dewlap or 
 great fold of skin on the neck, which is much less devel- 
 oped in the female. 
 
 "Now, what must we conclude with respect to such sexual 
 differences as these? No one will pretend that the beards 
 of certain male goats, or the dewlap of the bull, or the 
 crests of hair along the backs of certain male antelopes, 
 are of any use to them in their ordinary habits. It is pos- 
 sible that the immense beard of the male Pithecia, and the 
 large beard of the male orang, may protect their throats 
 when fighting ; for the keepers in the Zoological Gardens 
 inform me that many monkeys attack each other by the 
 throat; but it is not probable that the beard has been 
 developed for a distinct purpose from that served by the 
 whiskers, mustache and other tufts of hair on the face; 
 and no one will suppose that these are useful as a protec- 
 tion. Must we attribute all these appendages of hair or 
 skin to mere purposeless variability in the male? It cannot 
 be denied that this is possible; for in many domesticated 
 quadrupeds certain characters, apparently not derived 
 through reversion from any wild parent form, are confined 
 to the males, or are more developed in them than in 
 females; for instance, the hump on the male zebu-cattle of 
 India, the tail of fat-tailed rams, the arched outline of the 
 forehead in the males of several breeds of sheep, and, 
 lastly, the mane, the long hairs on the hind legs, and the 
 dewlap of the male of the Berbura goat.* The mane, 
 which occurs only in the rams of an African breed of 
 sheep, is a true secondary sexual character, for, as I hear 
 from Mr. Winwood Reade, it is not developed if the animal 
 be castrated. Although we ought to be extremely cautious, 
 as shown in my work on " Variation under Domestication," 
 in concluding that any character, even with animals kept 
 by semi-civilized people, has not been subjected to selec- 
 tion by man, and thus augmented, yet in the cases just 
 specified this is improbablo; more especially as the charac- 
 ters are confined to the males, or are more strongly devel- 
 oped in them than in the females. If it were positively 
 
 * See the chapters on these several animals in vol. i, of my 
 " Variation of Animals under Domestication;" also vol. ii, p. 73; also 
 chap, xx, on the practice of selection by semi-civilized people. For 
 the Berbura goat, see Dr. Gray, " Catalogue," ibid, p. 157.
 
 MAMMALS. 609 
 
 known that the above African ram is a descendant of the 
 same primitive stock as the other breeds of sheep, and if 
 the Berbura male goat, with his mane, dewlap, etc., is 
 descended from the same stock as other goats, then, 
 assuming that selection has not been applied to these 
 characters, they must be due to simple variability, together 
 with sexually limited inheritance. 
 
 Hence it appears reasonable to extend this same view to 
 all analagous cases with animals in a state of nature. 
 Nevertheless I cannot persuade myself that it generally 
 holds good, as in the case of the extraordinary development 
 of hair on the throat and fore legs of the male Ammo- 
 tragus, or in that of the immense beard of the male 
 Pithecia. Such study as I have been able to give to nature 
 makes me believe that parts or organs which are highly 
 developed were acquired at some period for a special pur- 
 pose. With those antelopes in which the adult male is 
 more strongly colored than the female, and with those 
 monkeys on which the hair on the face is elegantly arranged 
 and colored in a diversfied manner, it seems probable that 
 the crests and tufts of hair were gained as ornaments; and 
 this I know is the opinion of some naturalists. If this be 
 correct, there can be little doubt that they were gained or 
 at least modified through sexual selection ; but how far 
 the same view may be extended to other mammals is 
 doubtful. 
 
 Color of the Hair and of the Naked Skin. I will first 
 give briefly all the cases known to me of male quadrupeds 
 differing in color from the females. "With marsupials, as I 
 am informed by Mr. Gould, the sexes rarely differ in this 
 respect; but the great red kangaroo offers a striking excep- 
 tion, " delicate blue being the prevailing tint in those parts 
 of the female which in the male are red/'* In the 
 Didelphis opossum of Cayenne the female is said to be a 
 little more red than the male. Of the rodents, Dr. Gray 
 remarks: " African squirrels, especially those found in the 
 tropical regions, have the fur much brighter and more vivid 
 at some seasons of the year than at others, and the fur of 
 
 *0sphranter rufus, Gould, "Mammals of Australia," 1863, vol. 
 li. On the Didelphis, Desmarest, " Mammalogie," p. 256.
 
 1 THE DESCENT OF MAN. 
 
 the male is generally brighter than that of the female."* 
 Dr. Gray informs me that he specified the African squir- 
 rels, because, from their unusually bright colors, they best 
 exhibit this difference. The female of the Mus minutus 
 of Russia is of a paler and dirtier tint than the male. In a 
 large number of bats the fur of the male is lighter than in 
 female, f Mr. Dobson also remarks, with respect to these 
 animals: " Differences, depending partly or entirely on the 
 possession by the male of fur of a much more brilliant hue, 
 or distinguished by different markings or by the greater 
 length of certain portions, are met only, to any appreciable 
 extent, in the frugivorous bats in which the sense of sight 
 is well developed." This last remark deserves attention, 
 as bearing on the question whether bright colors are ser- 
 viceable to male animals from being ornamental. In one 
 genus of sloths it is now established, as Dr. Gray states, 
 " that the males are ornamented differently from the 
 females that is to say, that they have a patch of soft short 
 hair between the shoulders, which is generally of a more 
 or less orange color, and in one species pure white. The 
 females, on the contrary, are destitute of this mark." 
 
 The terrestrial Carnivora and Insectivora rarely exhibit 
 sexual differences of any kind, including color. The ocelot 
 (Felis pardalis), however, is exceptional, for the colors of 
 the female, compared with those of the male, are " moins 
 apparentes, le fauve, etant plus terne, le blanc moins pur, 
 les raies ayant moins de largeur et les taches moins de ' 
 diam^tre."J The sexes of the allied Felis mitis also differ, 
 but in a less degree; the general hues of the female being 
 rather paler than in the male, with the spots less black. 
 The marine Carnivora or seals, on the other hand, some- 
 times differ considerably in color, and they present, as we 
 have already seen, other remarkable sexual differences. 
 Thus the male of the Of aria nigrescens of the southern 
 hemisphere is of a rich brown shade above ; while the 
 
 *" Annals and Mag. of Nat. Hist.," Nov., 1867, p. 325. On the 
 Mus minutus, Desraarest, " Mammalogie," p. 304. 
 
 f J. A. Allen, in "Bulletin of Mus. Comp. Zoolog. of Cambridge, 
 United States," 1869, p. 207. Mr. Dobson on sexual characters in 
 the Chiroptera, " Proc. Zoolog. Soc.," 1873, p. 241. Dr. Gray on 
 sloths, ibid, 1871, p. 436. 
 
 t Desmarest, " Mamraalogie," 1820, p. 220. On Fettt Mitit, Beng- 
 ger, ibid, s. 184.
 
 MAMMALS. 611 
 
 female, who acquires her adult tints earlier in life than the 
 male, is dark-gray above, the young of both sexes being of 
 a deep chocolate color. The male of the northern Plioca 
 groenlandica is tawny gray, with a curious saddle-shaped 
 dark mark on the back; the female is much smaller and 
 has a very different appearance, being " dull white or yel- 
 lowish straw-color, with a tawny hue on the back;" the 
 young at first are pure white, and can " hardly be dis- 
 tinguished among the icy hummocks and snow, their coloi 
 thus acting as a protection."* 
 
 With ruminants sexual differences of color occur more 
 commonly than in any other order. A difference of this 
 kind is general in the Strepsicerene antelopes; thus the 
 male nilghau (Portax picta) is bluish-grey and much darker 
 than the female, with the square white patch on the throat, 
 the white marks on the fetlocks and the black spots on the 
 ears all much more distinct. We have seen that in this 
 species the crests and tufts of hair are likewise more devel- 
 oped in the male than in the hornless female. I am 
 informed by Mr. Blyth that the male, without shedding 
 his hair, periodically becomes darker during the breeding- 
 season. Youug males cannot be distinguished from young 
 females until about twelve months old; and if the male is 
 emasculated before this period, he never, according to the 
 same authority, changes color. The importance of this 
 latter fact, as evidence that the coloring of the Portax is of 
 sexual origin, becomes obvious when we hearf that neither 
 the red summer coat nor the blue winter coat of the Virginian 
 deer is at all affected by emasculation. With most or all of 
 the highly ornamented species of Tregelaphus the males are 
 darker than the hornless females, and their crests of hair are 
 more fully developed. In the male of that magnificent ante- 
 lope, the Derbyan eland, the body is redder, the whole neck 
 much blacker and the white band which separates these 
 colors broader than in the female. In the Cape eland, also, 
 the male is slightly darker than the female. J 
 
 *Dr. Mnrie on the Otaria, " Proc. Zool. Soc.," 1869, p. 108. Mr. 
 R.' Brown on the P. groenlandica, ibid, 1868, p. 417. See also on the 
 colors of seals, Desmarest, ibid, pp. 243, 249. 
 
 f Judge Catpn, in "Trans. Ottawa Acad. of Nat. Sciences," 1868, 
 p. 4. 
 
 JDr. Gray, "Cat. of Mamm. in Brit. Mus.," part iii, 1852, pp. 
 J34-143, also Di. Gray, "Gleaniuers *roin tlie Menagerie of Kuowi-
 
 612 THE DESCENT OF MAN. 
 
 In the Indian black -buck (A. lezoartica), which 
 belongs to another tribe of antelopes, the male is very 
 dark, almost black ; while the hornless female is fawn- 
 colored. We meet in this species, as Mr. Blyth informs 
 me, with an exactly similar series of facts, as in the 
 Portax picta, namely, in the male periodically changing 
 color during the breeding-season, in the effects of emascu- 
 lation on this change, and in the young of both sexes being 
 indistinguishable from each other. In the Antilope niger 
 the male is black, the female, as well as the young of both 
 sexes, being brown; in A. sing-sing the male is much 
 brighter-colored than the hornless female, and his chest 
 and belly are blacker; in the male A. caama the marks 
 and lines which occur on various parts of the body are 
 black, instead of brown as in the female; in the brindled 
 gnu (A. gorgon) " the colors of the male are nearly the 
 same as those of the female, only deeper and of a brighter 
 hue." * Other analogous cases could be added. 
 
 The Banteng bull (Bos sondaicus] of the Malayan Archi- 
 pelago is almost black, with white legs and buttocks; the 
 cow is of a bright dun, as are the young males until about 
 the age of three years, when they rapidly change color. 
 The emasculated bull reverts to the color of the female. The 
 female Kemas goat is paler, and both it and the female Capra 
 cegagrus are said to be more uniformly tinted than their 
 males. Deer rarely present any sexual differences in color. 
 Judge Caton, however, informs me ohat in the males of the 
 wapiti deer (Cervus canadensis] the neck, belly and legs 
 are much darker than in the female; but during the 
 winter the darker tints gradually fade away and disappear. 
 I may here mention that Judge Caton has in his park three 
 races of the Virginian deer which differ slightly in color, 
 but the differences are almost exclusively confined to the 
 blue winter or breeding coat; so that this case may be corn- 
 ley," in which there is a splendid drawing of the Oreas derbianus: 
 see the text on Tragelaphus. For the Cape eland (Oreas canna), see 
 Andrew Smith, " Zoology of S. Africa," pi. 41, 42. There are also 
 many of these antelopes in the Zoological Gardens. 
 
 *On the Ant. niger, see "Proc. Zool. Soc.," 1850, p. 133. With 
 respect to an allied species, in which there is an equal sexual differ- 
 ence in color, see Sir S. Baker, " The Albert Nyanza," 1866, vol. ii, 
 p. 627. For the A. sing -sing, Gray, " Cat. B. Mus.," p. 100. Des- 
 marest, "Mammalogie," p. 468, on the A. caama, Andrew Smith, 
 " Zoology of S. Africa," on the gnu.
 
 MAMMALS. 613 
 
 pared with those given in a previons chapter of closely 
 allied or representative species of birds which differ from 
 each other only in their breeding plumage.* The females 
 of Cervus paludosus of South America, as well as the 
 young of both sexes, do not possess the black stripes on the 
 nose and the blackish-brown line on the breast which are 
 characteristic of the adult males, f Lastly, as I am 
 informed by Mr. Blyth, the mature male of the beautifully 
 colored and spotted axis deer is considerably darker than 
 the female ; and this hue the castrated male never 
 acquires. 
 
 The last order which we need consider is that of the 
 Primates. The male of the Lemur macaco is generally 
 coal-black, while the female is brown. J Of the Quadru- 
 mana of the New World, the females and young of Mycetes 
 caraya are grayish-yellow and like each other; in the second 
 year the young male becomes reddish-brown; in the third, 
 black, excepting the stomach, which, however, becomes 
 quite black in the fourth or fifth year. There is also a 
 strongly marked difference in color between the sexes of 
 Mycetes seniculus and Cebus capucinus; the young of the 
 former, and I believe of the latter species, resembling the 
 females. With Pithccia leucocepliala the young likewise 
 resemble the females, which are brownish-black above and 
 light rusty-red beneath, the adult males being black. The 
 ruff of hair round the face of Ateles marginatus is tinted 
 yellow in the male and white in the female. Turning to 
 the Old World, the males of Hylobates hoolock are always 
 black, with the exception of a white band over the brows; 
 the females vary from whity-brown to a dark tint mixed 
 with black, but are never wholly black. In the beautiful 
 
 * "Ottawa Academy of Sciences," May 21, 1868, pp. 3, 5. 
 
 fS. Mailer, on the Banteng, "Zool. Indischen Archipel.," 1839- 
 1844, tab. 35; see also Raffles, as quoted by Mr. Blyth, in " Land 
 and Water," 1867, p. 476. On goats, Dr. Gray, " Cat. Brit. Mus.," 
 p. 146; Desmarest, " Mammalogie," p. 482. On the Cervus palu- 
 dosus, Rengger, ibid, B. 345. 
 
 'JSclater, "Proc. Zool. Soc.," 1866, p. 1. The same fact has also 
 been fully ascertained by MM. Pollen and van Dam. See, also, Dr. 
 Gray in " Annals and Mag. of Nat. Hist.," May, 1871, p. 340. 
 
 0n Mycetes, Rengger, ibid, s. 14; and Brehm, " Illustrirtes 
 Thierleben," B. i, ss. 96, 107. On Ateles Desmarest, "Mammal- 
 ogie," p. 75. On Kylobates, Blyth, "Land and Water," 1867, p. 
 135. On the Semnopithecus, S. Miiller, " Zoog. Indischen Archi- 
 pel.," tab. x.
 
 614 THE DESCENT OF MAN, 
 
 Cercopithecus diana, the head of the adult male is of an 
 intense black, while that of the female is dark gray; in the 
 former the fur between the thighs is of an elegant fawn- 
 color, in the latter it is paler. In the beautiful and curious 
 mustache monkey ( Cercopithecus cephus) the only differ- 
 ence between the sexes is that the tail of the male is 
 chestnut and that of the female gray; but Mr. Bartlett 
 informs me that all the hues become more pronounced in 
 the male when adult, while in the female they remain as 
 they were during youth. According to the colored figures 
 given by Solomon Miiller, the male of Semnopithecus 
 cJirysomelas is nearly black, the female being pale brown. 
 In the Cercopithecus cynosurus and griseoviridis one part 
 of the body, which is confined to the male sex, is of the 
 most brilliant blue or green, and contrasts strikingly with 
 the naked skin on the hinder part of the body, which is 
 vivid red. 
 
 Lastly, in the baboon family, the adult male of Cyno- 
 cephalus hamadryas differs from the female not only by his 
 immense mane, but slightly in the color of the hair and 
 of the naked callosities. In the drill (C. leucophceus) the 
 females and young are much paler colored, with less green 
 than the adult males. No other member in the whole 
 class of mammals is colored in so extraordinary a manner 
 as the adult male mandrill (C. mormon}. The face at this 
 age becomes of a fine blue, with the ridge and tip of the 
 nose of the most brilliant red. According to some authors 
 the face is also marked with whitish stripes, and is shaded 
 in parts with black, but the colors appear to be variable. 
 On the forehead there is a crest of hair, and on the chin a 
 yellow beard. " Toutes les parties superieures de leurs 
 cuisses et le grand espace nu de leurs fesses sont egalement 
 colores du rouge le plus vif, avec un melange de bleu qui 
 ne manque reellement pas d'elegance."* When the animal 
 is excited all the naked parts become much more vividly 
 tinted. Several authors have used the strongest expres- 
 sions in describing these resplendent colors, which they com- 
 pare with those of the most brilliant birds. Another remark- 
 
 *Gervais, "Hist. Nat. des Mammiferes," 1854, p. 103. Figures 
 are given of the skull of the male. Also Desmarest, " Mammal- 
 ~- ! - " p. 70. Geoffrey St.-Hilaire and F. Cuvier. "Hist. Nat. des 
 184, torn. i.
 
 MAMMALS. 
 
 615 
 
 able peculiarity is that when the great canine teeth are 
 fully developed, immense protuberances of bone are formed 
 on each cheek, which are deeply furrowed longitudinally, 
 and the naked skin over them is brilliantly colored, as just 
 described. (Fig. 69.) In the adult females and in the 
 young of both sexes these protuberances are scarcely per- 
 
 Fig. 69 Head of male Mandrill (from Gervais, " Hist. Nat. des Mammifcres "). 
 
 ceptible; and the naked parts are much less bright colored, 
 the face being almost black, tinged with blue. In the 
 adult female, however, the nose at certain regular intervals 
 of time becomes tinted with red. 
 
 In all the cases hitherto given the male is more strongly 
 or brighter colored than the female, and differs from the
 
 616 THE DESCENT OF MAN. 
 
 young of both sexes. But as with some few birds it is the 
 female which is brighter colored than the male, so with 
 the Rhesus monkey (Macacns rliestis), the female has a 
 large surface of naked skin round the tail, of a brilliant 
 carmine red, which, as I was assured by the keepers in the 
 Zoological Gardens, periodically becomes even yet more 
 vivid, and her face also is pale red. On the other hand, in 
 the adult male and in the young of both sexes (as I saw in 
 the gardens), neither the naked skin at the posterior end 
 of the body, nor the face, show a trace of red. It appears, 
 however, from some published accounts, that the male does 
 occasionally, or during certain seasons, exhibit some traces 
 of the red. Although he is thus less ornamented than the 
 female, yet in the larger size of his body, larger canine 
 teeth, more developed whiskers, more prominent super- 
 ciliary ridges, he follows the common rule of the male ex- 
 celling the female. 
 
 I have now given all the cases known to me of a dif- 
 ference in color between the sexes of mammals. Some of 
 these may be the result of variations confined to one sex 
 and transmitted to the same sex, without any good being 
 gained, and therefore without the aid of selection. We 
 have instances of this with our domesticated animals, as in 
 the males of certain cats being rusty-red, while the females 
 are tortoise-shell colored. Analogous cases occur in nature: 
 Mr. Bartlett has seen many black varieties of the jaguar, 
 leopard, vulpine phalanger and wombat; and he is certain 
 that all, or nearly all these animals, were males. On the 
 other hand, with wolves, foxes, and apparently American 
 squirrels, both sexes are occasionally born black. Hence 
 it is quite possible that with some mammals a difference of 
 color between the sexes, especially when this is congenital, 
 may simply be the result, without the aid of selection, of 
 the occurrence of one or more variations, which from the 
 first were sexually limited in their transmission. Never- 
 theless it is improbable that the diversified, vivid, and con- 
 trasted colors of certain quadrupeds, for instance, of the 
 above monkeys and antelopes, can thus be accounted for. 
 We should bear in mind that these colors do not appear in 
 the male at birth, but only at or near maturity; and that, 
 unlike ordinary variations, they are lost if the male be 
 emasculated. It is on the whole probable that the strongly
 
 MAMMALS. 617 
 
 marked colors and other ornamental characters of male 
 quadrupeds are beneficial to them in their rivalry with 
 other males, and have consequently been acquired through 
 sexual selection. This view is strengthened by the dif- 
 ferences in color between the sexes occurring almost ex- 
 clusively, as may be collected from the previous details, in 
 those groups and sub-groups of mammals which present 
 other and strongly marked secondary sexual characters; 
 these being likewise due to sexual selection. 
 
 Quadrupeds manifestly take notice of color. Sir S. 
 Baker repeatedly observed that the African elephant and 
 rhinoceros attacked white or gray horses with special fury. 
 I have elsewhere shown* that half-wild horses apparently 
 prefer to pair with those of the same color, and that herds 
 of fallow-deer of different colors, though living together, 
 have long kept distinct. It is a more significant fact that 
 a female zebra would not admit the addresses of a male ass 
 until he was painted so as to resemble a zebra, and then, as 
 John Hunter remarks, "she received him very readily. 
 In this curious fact, we have instinct excited by mere 
 color, which had so strong an effect as to get the better of 
 everything else. But the male did not require this; the 
 female being an animal somewhat similar to himself, was 
 sufficient to rouse him." f 
 
 In an earlier chapter we have seen that the mental 
 powers of the higher animals do not differ in kind, though 
 greatly in degree, from the corresponding powers of man, 
 especially of the lower and barbarous races; and it would 
 appear that even their taste fort the beautiful is not widely 
 different from that of the Quadrumana. As the negro of 
 Africa raises the flesh on his face into parallel ridges " or 
 cicatrices, high above the natural surface, which unsightly 
 deformities are considered great personal attractions;"! as 
 negroes and savages in many parts of the world paint their 
 faces with red, blue, white or black bars so the male man- 
 drill of Africa appears to have acquired his deeply furrowed 
 and gaudily colored face from having been thus rendered 
 
 *"The Variation of Animals and Plants under Domestication." 
 1868, vol. ii, pp. 102, 103. 
 
 J" Essays and Observations by J. Hunter," edited by Owen, 1861, 
 . i, p. 194. 
 J Sir S. Baker, "The Nile Tributaries of Abyssinia," 1867.
 
 618 THE DESCENT OF MAN. 
 
 attractive to the female. No doubt it is to ug a most 
 grotesque notion that the posterior end of the body should 
 be colored for the sake of ornament even more brilliantly 
 than the face; but this is not more strange than that the 
 tails of many birds should be especially decorated. 
 
 With mammals we do not at present possess any evidence 
 that the males take pains to display their charms before 
 the female; and the elaborate manner in which this is per- 
 formed by male birds and other animals is the strongest 
 argument in favor of the belief that the females admire, 
 or are excited by, the ornaments and colors displayed 
 before them. There is, however, a striking parallelism 
 between mammals and birds in all their secondary sexual 
 characters, namely, in their weapons for fighting with rival 
 males, in their ornamental appendages and in their colors. 
 In both classes, when the male differs from the female, the 
 young of both sexes almost always resemble each other, and 
 in a large majority of cases resemble the adult female. In 
 both classes the male assumes the characters proper to his 
 sex shortly before the age of reproduction; and if emas- 
 culated at an early period loses them. In both classes the 
 change of color is sometimes seasonal, and the tints of the 
 naked parts sometimes become more vivid during the act of 
 courtship. In both classes the male is almost always more 
 vividly or strongly colored than the female, and is orna- 
 mented with larger crests of hair or feathers, or other 
 such appendages. In a few exceptional cases the female in 
 both classes is more highly ornamented than the male. 
 With many mammals, and at least in the case of one bird, 
 the male is more odoriferous than the female. In both 
 classes the voice of the male is more powerful than that of 
 the female. Considering this parallelism, there can be 
 little doubt that the same cause, whatever it may be, has 
 acted on mammals and birds; and the result, as far as 
 ornamental characters are concerned, may be attributed, 
 as it appears to me, 'to the long-continued preference of the 
 individuals of one sex for certain individuals of the opposite 
 sex, combined with their success in leaving a larger 
 number of offspring to inherit their superior attractions. 
 
 Equal Transmission of Ornamental Characters to Both 
 Sexes. With many birds, ornaments, which analogy leads 
 us to believe were primarily acquired by the males, have
 
 MAMMALS. 619- 
 
 been transmitted equally, or almost equally, to both sexes; 
 and we may now inquire how far this view applies to mam- 
 mals. With a considerable number of species, especially 
 of the smaller kinds, both sexes have been colored, inde- 
 pendently of sexual selection, for the sake of protection; 
 but not, as far as I can judge, in so many cases, nor in so 
 striking a manner, as in most of the lower classes. Audu- 
 'bon remarks that he often mistook the muskrat,* while 
 sitting on the banks of a muddy stream, for a clod of earth, 
 so complete was the resemblance. The hair on her form is 
 a familiar instance of concealment through color; yet this 
 principle partly fails in a closely allied species, the rabbit, 
 for when running to its burrow, it is made conspicuous to 
 the sportsman, and, no doubt, to all beasts of prey, by its 
 upturned white tail. No one doubts that the quadrupeds 
 inhabiting snow-clad regions have been rendered white to 
 protect them from their enemies, or to favor their stealing 
 on their prey. In regions where snow never lies for long, 
 a white coat would be injurious; consequently, species of 
 this color are extremely rare in the hotter parts of the 
 world. It deserves notice that many quadrupeds inhabit- 
 ing moderately cold regions, although they do not assume 
 a white winter dress, become paler during this season; and 
 this apparently is the direct result of the conditions to 
 which they have long been exposed. Pallas f states that in 
 Siberia a change of this nature occurs with the wolf, two 
 species of Mustela, the domestic horse, the Equus hemionus, 
 the domestic cow, two species of antelopes, the musk-deer, 
 the roe, elk and reindeer. The roe, for instance, has a red 
 summer and a grayish- white winter coat; and the latter 
 may, perhaps, serve as a protection to the animal while 
 wandering through the leafless thickets, sprinkled with 
 snow and hoar-frost. If the above-named animals were 
 gradually to extend their range into regions perpetually 
 covered with snow their pale winter coats would probably 
 be rendered, through natural selection, whiter and whiter, 
 until they became as white as snow. 
 .Mr. Reeks has given me a curious instance of an animal 
 
 * Fiber zibethicus, Audubon and Bachman, "The Quadrupeds of 
 North America," 1846, p. 109. 
 
 j- " Novae species Quadrupedum e Glirium ordine," 1778, p. 7. 
 What I have called the roe is the Capreelus sibiricus svbecaudatus of 
 Pallas.
 
 620 
 
 THE DESCENT OF MAN. 
 
 profiting by being peculiarly colored. He raised from fifty 
 to sixty white and brown piebald rabbits in a large walled 
 orchard; and he had at the same time some similarly 
 colored cats in his house. Such cats, as I have often 
 noticed, are very conspicuous during the day; but, as they 
 
 Pig. 70. Tragelaphus scrlptus, maie (from the Knowsley Meriagerie). 
 
 used to lie in watch during the dusk at the mouths of the 
 burrows, the rabbits apparently did not distinguish them 
 from their party-colored brethren. The result was that, 
 within eighteen months, every one of these party-colored 
 rabbits was destroyed; and there was evidence that this 
 was effected by the cats. Color seems to be advantageous 
 to another animal, the skunk, in a manner of which we 
 have had many instances in other classes. No animal will 
 voluntarily attack one of these creatures on account of the 
 dreadful odor which it emits when irritated; but during the
 
 MAMMALS. 621 
 
 dttSK it would not easily be recognized and might be attacked 
 by a beast of prey. Hence it is, as Mr. Belt believes, * that the 
 skunk is provided with a great white bushy tail, which 
 serves as a conspicuous warning. 
 
 Although we must admit that many quadrupeds have 
 received their present tints either as a protection, or as an 
 aid in procuring prey, yet with a host of species, the colors 
 are far too conspicuous and too singularly arranged to 
 allow us to suppose that they serve for these purposes. We 
 may take as an illustration certain antelopes; when we see 
 the square white patch on the throat, the white marks on 
 the fetlocks, and the round black spots on the ears, all more 
 distinct in the male of the Portax picta, than in the 
 female when we see that the colors are more vivid, that 
 the narrow white lines on the flank and the broad white 
 bar on the shoulder are more distinct in the male Oreas 
 derby anus than in the female when we see a similar 
 difference between the sexes of the curiously ornamented 
 Tragelaplius scriptus (fig. 70) we cannot believe that 
 differences of this kind are of any service to either sex in 
 their daily habits of life. It seems a much more probable 
 conclusion that the various marks were first acquired by 
 the males and their colors intensified through sexual selec- 
 tion, and then partially transferred to the females. If this 
 view be admitted, there can be little doubt that the equally 
 singular colors and marks of many other antelopes, though 
 common to both sexes, have been gained and transmitted 
 in a like manner. Both sexes, for instance, of the koodoo 
 (Strepsiceros kudu) (fig. 64) have narrow white vertical 
 lines on their hind flanks, and an elegant angular white 
 mark on their foreheads. Both sexes in the genus Dam- 
 alis are very oddly colored; in D. pygarga the back and 
 neck are purplish-red, shading on the flanks into black ; 
 and these colors are abruptly separated from the white 
 belly and from a large white space on the buttocks; the head 
 is still more oddly colored, a large oblong white mask, nar- 
 rowly edged with black, covers the face up to the eyes 
 (fig. 71}; there are three white stripes on the forehead and 
 the ears are marked with white. The fawns of this species 
 are of a uniform pale yellowish brown. In Damalis albi- 
 frons the coloring of the head differs from that in the last 
 
 * " The Naturalist in Nicaragua," p. 249.
 
 THE DESCENT OF MAN. 
 
 species in a single white stripe replacing the three stripes, 
 and in the ears being almost wholly white.* After having 
 studied to the best of my ability the sexual differences of 
 animals belonging to all classes,! cannot avoid the conclusion 
 that the curiously arranged colors of many antelopes, though 
 
 Pig. 71. Damalis pygarga, male (from the Knowsley Menagerie). 
 
 common to both sexes, are the result of sexual selection 
 primarily applied to the male. 
 
 The same conclusion may perhaps be extended to the 
 tiger, one of the most beautiful animals in the world, the 
 sexes of which cannot be distinguished by color, even by 
 the dealers in wild beasts. Mr. Wallace believesf that the 
 striped coat of the tiger " so assimilates with the vertical 
 
 * See the fine plates in A. Smith's "Zoology of S. Africa," and Dr- 
 Gray's " Gleanings from the Menagerie of Knowsley." 
 f "Westminster Review." July I, 1967, p. 0.
 
 MAMMALS. 623 
 
 stems of the bamboo as to assist greatly in concealing him 
 from his approaching prey." But this view does not 
 appear to me satisfactory. We have some slight evidence 
 that his beauty may be due to sexual selection, for in two 
 species of Felis the analagous marks and colors are rather 
 brighter in the male than in the female. The zebra is con- 
 spicuously striped, and stripes cannot afford any protection 
 on the open plains of S. Africa. Burchell * in describing 
 a herd says: " Their sleek ribs glistened in the sun, and the 
 brightness and regularity of their striped coats presented a 
 picture of extraordinary beauty, in which probably they are 
 not surpassed ty any other quadruped." But as through- 
 out the whole group of the Equidse the sexes are identical 
 in color we have here no evidence of sexual selection. 
 Nevertheless he who attributes the white and dark vertical 
 stripes on the flanks of various antelopes to this process, 
 will probably extend the same view to the royal tiger and 
 beautiful zebra. 
 
 We have seen in a former chapter that when young ani- 
 mals belonging to any class follow nearly the same habits 
 of life as their parents, and yet are colored in a different 
 manner, it may be inferred that they have retained the 
 coloring of some ancient and extinct progenitor. In the 
 family of pigs, and in the tapirs, the young are marked 
 with longitudinal stripes, and thus differ from all the exist- 
 ing adult species in these two groups. With many kinds of 
 deer the young are marked with elegant white spots, 
 of which their parents exhibit not a trace. A graduated 
 series can be followed from the axis deer, both sexes of 
 which at all ages and during all seasons are beautifully 
 spotted (the male being rather more strongly colored than 
 the female), to species in which neither the old nor the 
 young are spotted. I will specify some of the stepson this 
 series. The Mantchurian deer (Cervus mantcJiuricus) is 
 spotted during the whole year, but, as I have seen in the 
 Zoological Gardens, the spots are much plainer during the 
 summer, when the general color of the" coat is lighter than 
 during the winter, when the general color is darker and the 
 horns are fully developed. In the hog-deer (Hyelaphus 
 porcinus) the spots are extremely conspicuous during the 
 summer when the coat is reddish-brown, but quite disap- 
 
 * " Travels in South Africa," 1824, vol. ii, p. 315.
 
 624 THE DESCENT OF MAN. 
 
 pear during the winter when the coat is brown.* In both 
 these species the young are spotted. In the Virginian deer 
 the young are likewise spotted, and about five per cent of the 
 adult animals living in Judge Caton's park, as I am 
 informed by him,, temporarily exhibit at the period when 
 the red summer coat is being replaced by the bluish winter 
 coat, a row of spots on each flank, which are always the 
 same in number, though very variable in distinctness. 
 From this condition there is but a very small step to the 
 complete absence of spots in the adults at all seasons; and, 
 lastly, to their absence at all ages and seasons, as occurs 
 with certain species. From the existence of this perfect 
 series, and more especially from the fawns of so many 
 species being spotted, we may conclude that the now living 
 members of the deer family are the descendants of some 
 ancient species which, like the axis deer, was spotted at all 
 ages and seasons. A still more ancient progenitor probably 
 somewhat resembled the Hyomosclms aquaticus for this 
 animal is spotted, and the hornless males have large 
 exserted canine teeth, of which some few true deer still 
 retain rudiments. Hyomoschus, also, offers one of those 
 interesting cases of a form linking together two groups, for 
 it is intermediate in certain osteological characters between 
 the pachyderms and ruminants, which were formerly 
 thought to be quite distinct, f 
 
 A curious difficulty here arises. If we admit that 
 colored spots and stripes were first acquired as ornaments, 
 how conies it that so many existing deer, the descendants 
 of an aboriginally spotted animal, and all the species 
 of pigs and tapirs, the descendants of an aboriginally 
 striped animal, have lost in their adult state their former 
 ornaments ? I cannot satisfactorily answer this question. 
 We may feel almost sure that the spots and stripes disap- 
 peared at or near maturity in the progenitors of our exist- 
 ing species, so that they were still retained by the young; 
 and, owing to the law of inheritance at corresponding ages, 
 were transmitted to the young of all succeeding generations. 
 
 *Dr. Gray, "Gleanings from the Menagerie of Knowsley," p. 64. 
 Mr. Blytli. in speaking (" Land and Water," 1869, p. 42) of the bog- 
 deer of Ceylon, says it is more brightly spotted with white than the 
 common hog-deer, at the season when it renews its horns. 
 
 f Falconer and Cautley, " Proc. Geolog. Soc.,"1843: and Falconer's 
 'Pal. Memoirs," vol. i, p. 196,
 
 MAMMALS. 
 
 625 
 
 It may have been a great advantage to the lion and puma, 
 from the open nature of their usual haunts, to have lost 
 their stripes, and to have been thus rendered less con- 
 spicuous to their prey; and if the successive variations, by 
 which this end was gained, occurred rather late in life the 
 young would have retained their stripes, as is now the case. 
 
 Fig. 72. Head of Semnopithecus rubicundus. This and the following figures 
 (from Prof. Gervais) are given to show the odd arrangement and develop- 
 ment of the hair on the head. 
 
 As to deer, pigs and tapirs, Fritz Miiller has suggested to 
 me that these animals, by the removal of their spots or 
 stripes through natural selection, would have been less 
 easily seen by their enemies; and that they would have 
 especially required this protection as soon as the carnivora 
 increased in size and number during the tertiary periods. 
 This may be the true explanation, but it is rather strange 
 that the young should not have been thus protected, and 
 still more so that the adults of some species should have
 
 626 TEE DESCENT OF MAN. 
 
 retained their spots, either partially or completely, during 
 part of the year. We know that when the domestic ass 
 varies and becomes reddish-brown, gray or black the stripes 
 on the shoulders and even on the spine frequently disap- 
 pear, though we cannot explain the cause. Very few 
 horses, except dun-colored kinds, have stripes on any part 
 of their bodies, yet we have good reason to believe that the 
 aboriginal horse was striped on the legs and spine, and 
 probably on the shoulders.* Hence the disappearance of 
 the spots and stripes in our adult existing deer, pigs and 
 tapirs may be due to a change in the general color of their 
 coats; but whether this change was effected through sexual 
 or natural selection, or was due to the direct action of the 
 conditions of life, or to some other unknown carse, it is 
 impossible to decide. An observation made by Mr. idolater 
 well illustrates our ignorance of the laws which regulate 
 the appearance and disappearance of stripes; the species of 
 Asinus which inhabit the Asiatic continent are destitute of 
 stripes, not having even the cross shoulder-stripe, while 
 those which inhabit Africa are conspicuously striped, with 
 the partial exception of A. tceniopus, which has only the 
 cross shoulder-stripe and generally some faint bars on the 
 legs; and this species inhabits the almost intermediate 
 region of Upper Egypt and Abyssinia, f 
 
 Quadrumana. Before we conclude, it will be well to 
 add a few remarks on the ornaments of monkeys. In most 
 of the species the sexes resemble each other in color, but in 
 some, as we have seen, the males differ from the females, 
 especially in the color of the naked parts of the skin, in 
 the development of the beard, whiskers and mane. Many 
 species are colored either in so extraordinary or so beautiful 
 a manner, and are furnished with such curious and elegant 
 crests of hair, that we can hardly avoid looking at these 
 characters as having been gained for the sake of ornament. 
 The accompanying figures (72 to 7G) serve to show 
 the arrangement of the hair on the face and head in sev- 
 eral species. It is scarcely conceivable that these crests of 
 
 *"The Variation of Animals and Plants under Domestication," 
 1868, vol. i, pp. 61-64. 
 
 f " Proc. Zool. Soc.," 1862, p. 164 See. also, Dr. Hartmau, " Ann. 
 d. Landw.," Bd. xliii, s. 32ft.
 
 MAMMALS. 62? 
 
 hair and the strongly contrasted colors of the fur and skin, 
 can be the result of mere variability without the aid of se- 
 lection; and it is inconceivable that they can be of use in 
 any ordinary way to these animals. If so, they have 
 probably been gained through sexual selection, though 
 transmitted equally, or almost equally, to both sexes. 
 
 Pig. 78. Head of Semnopithecus comatus. Fig. 74. Head of Cebus capucinua 
 
 Fig. 75. Head of Ateles marginatus. Fig. 76. Head of Cebus vellerosus. 
 
 With many of the Quadrumana, we have additional evi- 
 dence of the action of sexual selection in the greater size 
 and strength of the males, and in the greater development 
 of their canine teeth, in comparison with the females. 
 
 A few instances will suffice of the strange manner in 
 which both sexes of some species are colored and of the 
 beauty of others. The face of the Cercopithecus petaurista
 
 628 THE DESCENT OF MAN. 
 
 (fig. 77) is black, the whiskers and beard being white, with 
 
 
 Fig. 77. Cercopithecus petaurista (from Brehm). 
 
 a defined, round, white spot on the nose, covered with 
 short white hair, which gives to the animal an almost
 
 MAMMALS. 029 
 
 ludicrous aspect. The Semnopithecus frontatus likewise 
 has a blackish face with a long black beard, and a large 
 naked spot on the forehead of a bluish-white color. The 
 face of Macacus lasiotus is dirty flesh-colored, with a 
 denned red spot on each cheek. The appearance of 
 Cercocebus cethiops is grotesque, with its black face, white 
 whiskers and collar, chestnut head, and a large naked 
 white spot over each eyelid. In very many species the 
 beard, whiskers and crests of hair round the face are of a 
 different color from the rest of the head, and, when differ- 
 ent, are always of a lighter tint,* being often pure white, 
 sometimes bright yellow or reddish. The whole face of the 
 South American Brachyurus calvus is of a " glowing 
 scarlet hue;'' but this color does not appear until the ani- 
 mal is nearly mature, f The naked skin of the face differs 
 wonderfully in color in the various species. It is often 
 brown or flesh-color, with parts perfectly white, and often 
 as black as that of the most sooty negro. In the Brachyu- 
 rus the scarlet tint is brighter than that of the most blush- 
 ing Caucasian damsel. It is sometimes more distinctly 
 orange than in any Mongolian, and in several species it is 
 blue, passing into violet or gray. In all the species known 
 to Mr. Bartlett, in which the adults of both sexes have 
 strongly colored faces, the colors are dull or absent during 
 early youth. This likewise holds good with the mandril 
 and rhesus, in which the face and the posterior parts of the 
 body are brilliantly colored in one sex alone. In these 
 latter cases we have reason to believe that the colors were 
 acquired through sexual selection; and we are naturally Jed 
 to extend the same view to the foregoing species, though 
 both sexes when adult have their faces colored in the same 
 manner. 
 
 Although many kinds of monkeys are far from beautiful 
 according to our taste, other species are universally ad- 
 mired for their elegant appearance and bright colors. The 
 Semnopithecus nemceus, though peculiarly colored, is de- 
 scribed as extremely pretty; the orange-tinted face is sur- 
 rounded by long whiskers of glossy whiteness, with a line of 
 
 * I observed this fact in the Zoological Gardens; and many case* 
 may be seen in the colored plates in Geoffroy St.-Hilaire and F- 
 Cuvier, "Hist. Nat. des Mammif eres, " torn, i, 1824. 
 
 f Bates, "The Naturalist on the Amazons," 1868, vol. ii, p. 310.
 
 630 THE DESCENT OF MAN. 
 
 chestnut-red over the eyebrows; the fur on the back is of a 
 delicate gray, with a square patch on the loins, the tail 
 and the fore arms being of a pure white; a gorget of chest- 
 nut surmounts the chest; the thighs are black, with the 
 legs chestnut-red. I will mention only two other monkeys 
 for their beauty; and I have selected these as presenting 
 slight sexual differences in color, which renders it in some 
 degree probable that both sexes owe their elegant appear- 
 ance to sexual selection. In the mustache-monkey 
 (Cercopithecus cephus) the general color of the fur is mot- 
 tled-greenish with the throat white; in the male the end of 
 the tail is chestnut, but the face is the most ornamented 
 part, the skin being chiefly bluish-gray, shading into a 
 blackish tint beneath the eyes, with the upper lip of a deli- 
 cate blue, clothed on the lower edge with a thin black 
 mustache ; the whiskers are orange-colored, with the 
 upper part black, forming a band which extends back- 
 ward to the ears, the latter being clothed with whitish 
 hairs. In the Zoological Society's Gardens I have often 
 overheard visitors admiring the beauty of another monkey, 
 deservedly called Cercopithecus diana (fig. 78); the general 
 color of the fur is gray; the chest and inner surface of the 
 fore legs are white; a large triangular defined space on the 
 hinder part of the back is rich chestnut; in the male the 
 inner sides of the thighs and the abdomen are delicate 
 fawn-colored, and the top of the head is black; the face 
 and ears are intensely black, contrasting finely with a white 
 transverse crest over the eyebrows and a long white peaked 
 beard, of which the basal portion is black.* 
 
 In these and many other monkeys the beauty and sin- 
 gular arrangement of their colors, and still more the diver- 
 sified and elegant arrangement of the crests and tufts of 
 hair on their heads, force the conviction on my mind 
 that these characters have been acquired through sexual 
 selection exclusively as ornaments. 
 
 Summary. The law of battle for the possession of the 
 female appears to prevail throughout the whole great class 
 of mammals. Most naturalists will admit that the greater 
 
 * I have seen most of the above monkeys in the Zoological 
 Society's Gardens. The description of the Semnopithecus nemaus ia 
 taken from Mr. W. C. Martin's "Nat. Hist, of Mammalia," 1841, p. 
 460; Bee also pp. 475, 528.
 
 MAMMALS. 
 
 631 
 
 size, strength, courage and pugnacity of the male, his 
 special weapons of offense, as well as his special means of 
 defense, have been acquired or modified through that form 
 of selection which I have called sexual. This does not 
 depend on any superiority in the general struggle for life, 
 
 Kg. 78. Cercopithecus diana (from Brehm). 
 
 but on certain individuals of one sex, generally the male, 
 being successful in conquering other males, and leaving a 
 larger number of offspring to inherit their superiority than 
 do tbe less successful males. 
 
 There is another and more peaceful kind of contest, in
 
 6355 THE DESCENT OF MAN. 
 
 which the males endeavor to excite or allure the females Ly 
 various charms. This is probably carried on in some cases 
 by the powerful odors emitted by the males during the 
 breeding-season; the odoriferous glands having been acquired 
 through sexual selection. Whether the same view can be 
 extended to the voice is doubtful, for the vocal organs of 
 the males must have been strengthened by use during 
 maturity, under the powerful excitements of love, jealousy 
 or rage, and will consequently have been transmitted to the 
 same sex. Various crests, tufts and mantles of hair, which 
 are either confined to the male, or are more developed in 
 this sex than in the female, seem in most cases to be merely 
 ornamental, though they sometimes serve as a defense 
 against rival males. There is even reason to suspect that 
 the branching horns of stags and the elegant horns of cer- 
 tain antelopes, though properly serving as weapons of 
 oifense or defense, have been partly modified for ornament. 
 When the male differs in color from the female, he gen- 
 erally exhibits darker and more strongly contrasted tints. 
 W T e do not in this class meet with the splendid red, blue, 
 yellow and green tints so common with male birds and 
 many other animals. The naked parts, however, of cer- 
 tain Quadrumana must be excepted; for such parts, often 
 oddly situated, are brilliantly colored in some species. The 
 colors of the male in other cases may be due to simple 
 variation without the aid of selection. But when the colors 
 are diversified and strongly pronounced, when they are not 
 developed until near maturity, and when they are lost after 
 emasculation, we can hardly avoid the conclusion that they 
 have been acquired through sexual selection for the sake of 
 ornament and have been transmitted exclusively, or almost 
 exclusively, to the same sex. When both sexes are colored in 
 the same manner, and the colors are conspicuous or 
 curiously arranged, without being of the least apparent use 
 as a protection, and especially when they are associated 
 with various other ornamental appendages, we are led by 
 analogy to the same conclusion, namely, that they have 
 been acquired through sexual selection, although trans- 
 mitted to both sexes. That conspicuous and diversified 
 colors, whether confined to the males or co'mmon to both 
 sexes, are as a general rule associated in the same groups 
 and sub-groups with other secondary sexual characters serv- 
 ing for war or for ornament will be found to hold good, if
 
 MAMMALS. 633 
 
 we look back to the various cases given in this and the 
 last chapter. 
 
 The law of the equal transmission of characters to both 
 sexes, as far as color and other ornaments are concerned, 
 has prevailed far more extensively with mammals than with 
 birds; but weapons, such as horns and tusks, have often 
 been transmitted either exclusively or much more perfectly 
 to the males than to the females. This is surprising, for, 
 as the males generally use their weapons for defense against 
 enemies of all kinds, their weapons would have been of 
 service to the females. As far as we can see their absence 
 in this sex can be accounted for only by the form of inher- 
 itance which has prevailed. Finally, with quadrupeds the 
 contest between the individuals of the same sex, whether 
 peaceful or bloody, has, with the rarest exceptions, been 
 confined to the males; so that the latter have been modified 
 through sexual selection, far more commonly than the 
 females, either for fighting with each other or for alluring 
 the opposite sex.
 
 PART III. 
 SEXUAL SELECTION IN RELATION TO MAN. 
 
 CHAPTER XIX. 
 
 SECONDARY SEXUAL CHAEACTERS OF MAN. 
 
 Differences between man and woman Causes of such differences 
 and of certain characters common to both sexes Law of battle 
 Differences in mental powers and voice On the influence of 
 beauty in deterniinging the marriages of mankind Attention 
 paid by savages to ornaments Their ideas of beauty in woman 
 The tendency to exaggerate each natural peculiarity. 
 
 WITH mankind the differences between the sexes are 
 greater than in most of the Quadrumana, but not so great 
 as in some, for instance, the mandrill. Man on an average 
 is considerably taller, heavier and stronger than woman, 
 with squarer shoulders and more plainly pronounced mus- 
 cles. Owing to the relation which exists between muscular 
 development and the projection of the brows,* the super- 
 ciliary ridge is generally more marked in man than in 
 woman. His body, and especially his face, is more hairy,' 
 and his voice has a different and more powerful tone, 
 In certain races the women are said to differ slightly in tint 
 from the men. For instance, Schweinfurth, in speaking 
 of a negress belonging to the Monbuttoos, who inhabit the 
 interior of Africa a few degrees north of the equator, 
 says: "Like all her race, she had a skin several shades 
 lighter than her husband's, being something of the color of 
 half-roasted coffee. "f As the women labor in the fields 
 and are quite unclothed, it is not likely that they differ in 
 color from the men owing to less exposure to the weather. 
 
 *Schaaffhausen, translation in "Anthropological Review," Oct., 
 1868, pp. 419, 420, 427. 
 f"The Heart of Africa," English transl ., 1873, vol.-i., p. 544
 
 SECONDARY SEXUAL CHARACTERS. 635 
 
 European women are perhaps the brighter colored of the 
 two sexes, as may be seen when both have been equally 
 exposed. 
 
 Man is more courageous, pugnacious and energetic than 
 woman, and has a more inventive genius. His brain is 
 absolutely larger, but whether or not proportionately to his 
 larger body, has not, I believe, been fully ascertained. In 
 woman the face is rounder; the jaws and the base of the 
 skull smaller; the outlines of the body rounder, in parts 
 more prominent; and her pelvis is broader than in trin;* 
 but this latter character may perhaps be considered rather 
 as a primary than a secondary sexual character. She comes 
 to maturity at an earlier age than man. 
 
 As Avith animals of all classes, so with man, the dis- 
 tinctive characters of the male sex are not fully developed 
 until he is nearly mature; and, if emasculated, they never 
 appear. The beard, for instance, is a secondary sexual 
 character, and male children are beardless, though at an 
 early age they have abundant hair on the head. It is 
 probably due to the rather late appearance in life of the 
 successive variations whereby man has acquired his mascu- 
 line characters that they are transmitted to the male sex 
 alone. Male and female children resemble each other 
 closely, like the young of so many other animals in which 
 the adult sexes differ widely; they likewise resemble the 
 mature female much more closely than the mature male. 
 The female, however, ultimately assumes certain distinctive 
 characters, and, in the formation of her skull, is said to be 
 intermediate between the child and the man. f Again, as 
 the young of closely allied though distinct species do not 
 differ nearly so much from each other as do the adults, so 
 it is with the children of the different races of man. Some 
 have even maintained that race - differences cannot be 
 detected in the infantile skull. J In regard to color, the 
 new-born negro child is reddish nut-brown, which soon 
 becomes slaty-gray; the black color being fully developed 
 
 *Ecker, translation in "Anthropological Review," Oct., 1868, pp. 
 351-356. The comparison of the form of the skull in men and 
 women has been followed out with much care by Welcker. 
 
 fEcker and Welcker, ibid, pp, 352, 355; Vogt, "Lectures on 
 Man," Eng. translat., p. 81. 
 
 tSchaaffhausen. " Anthropolog. Review," ibid, p. 429.
 
 636 THE DESCENT OF MAN. 
 
 within a year in the Soudan, but not until three years in 
 Egypt. The eyes of the negro are at first blue, and the 
 hair chestnut-brown rather than black, being curled only 
 at the ends. The children of the Australians immediately 
 after birth are yellowish-brown, and become dark at a later 
 age. Those of the Gunaranys of Paraguay are whitish- 
 yellow, but they acquire, in the course of a few weeks, the 
 yellowish-brown tint of their parents. Similar observations 
 have been made in other parts of America.* 
 
 I have specified the foregoing differences between the 
 male and female sex in mankind, because they are curiously 
 like those of the Quadrumana. With these animals 
 the female is mature at an earlier age than the male; at 
 least this is certainly the case in Cebus azarce. \ The males 
 of jiiost species are larger and stronger than the females, 
 of which fact the gorilla affords a well-known instance. 
 Even in so trifling a character as the greater prominence 
 of the superciliary ridge, the males of certain monkeys 
 differ from the females, J and agree in this respect with 
 mankind. In the gorilla and certain other monkeys the 
 cranium of the adult male presents a strongly marked 
 sagittal crest, which is absent in the female; and Ecker 
 found a trace of a similar difference between the two sexes 
 in the Australians.! With monkeys, when there is any 
 difference in the voice, that of the male is the more pow- 
 erful. We have seen that certain male monkeys have a 
 well-developed beard, which is quite deficient, or much less 
 developed, in the female. No instance is known of the 
 beard, whiskers or mustache being larger in the female than 
 in the male monkey. Even in the color of the beard there 
 is a curious parallelism between man and the Quadrumana, 
 
 * Pruner-Bey, on negro infants, as quoted by Vogt, " Lectures on 
 Man," Eng. translat., 1864, p. 189; for further facts on negro infants, 
 as quoted from Winterbottom and Camper, see Lawrence, " Lectures 
 on Physiology," etc., 1822, p. 451. For theinfantsof theGunaranya 
 see Kengger, "Saugethiere," etc., s. 3. See also Godron, " De 
 1'Espece," torn, ii, 1859, p. 253. For the Australians, Waitz, " Intro- 
 duct, to Anthropology, "Eng. translat., 1863, p. 99. 
 
 j- Rengger, "Saugethiere," etc,, 1830, s. 19. 
 
 r l As in Macacus cynomolgus (Desmarest, "Mammalogie," p. 65), 
 and in Hylobates agilis (Geoffroy St.-Hilaire and F. Cuvier, "Hist. 
 Nat. des Mamni.," 1824, torn, i, p. 2). 
 
 | " Anthropological Review, " Oct., 1868, p. 353.
 
 SECONDARY SEXUAL CHARACTERS. 637 
 
 for with man when the beard differs^in color from the hair 
 of the head, as is commonly the case* it is, I believe, almost 
 always of a lighter tint, being often reddish. I have 
 repeatedly observed this fact in England; but two gentle- 
 men have lately written to me, saying that they form an 
 exception to the rule. One of these gentlemen accounts 
 for the fact by the wide difference in color of the hair on the 
 paternal and maternal sides of his family. Both had long 
 been aware of this peculiarity (one of them having often been 
 accused of dyeing his beard), and had been thus led to observe 
 other men, and were convinced that the exceptions were 
 very rare. Dr. Hooker attended to this little point for me 
 in Russia, and found no exception to the rule. In Calcutta 
 Mr. J. Scott, of the Botanic Gardens, was so kind as to 
 observe the many races of men to be seen there, as well 
 as in some other parts of India, namely, two races of 
 Sikhim, the Bhoteas, Hindoos, Burmese and Chinese, most 
 of which races have very little hair on the face; and he 
 always found that when there was any difference in color 
 between the hair of the head and the beard, the latter was 
 invariably lighter. Now with monkeys, as has already 
 been stated, the beard frequently differs strikingly in color 
 from the hair of the head, and in such cases it is always of 
 a lighter hue, being often pure white, sometimes yellow or 
 reddish.* 
 
 In regard to the general hairiness of the body, the 
 women in all races are less hairy than the men ; and in 
 some few Quadrumana the under side of the body 
 of the female is less hairy than that of the male.f 
 Lastly, male monkeys, like men, are bolder and fiercer 
 
 * Mr. Blyth informs me that he has only seen one instance of the 
 beard, whiskers, etc., in a monkey becoming white with old age, as 
 is so commonly the case with us. This, however, occurred in an 
 aged Macacus cynamolgus, kept in confinement, whose mustaches 
 were " remarkably long and human-like." Altogether this old 
 monkey presented a ludicrous resemblance to one of the reigning 
 monarchs of Europe, after whom he was universally nick-named. 
 In certain- races of man the hair on the head hardly ever becomes 
 gray; thus Mr. D. Forbes has never, as he informs me, seen an 
 instance with the Aymaras and Quchuas of South America. 
 
 f This is the case with the females of several species of Hylobates. 
 See Geoffrey St.-Hilaire and F. Cuvier, "Hist. Xat. des Manirn.," 
 torn. i. See, also, on H. lar, "Penny Cyclopedia," voL ii, pp. 149, 
 150.
 
 638 THE DESCENT OF MAN. 
 
 than the females. They lead the troop, and, when there is 
 danger, come to the front. We thus see how close is tho 
 parallelism between the sexual differences of man and the 
 Quadrumana. With some few species, however, as with 
 certain baboons, the orang and the gorilla, there is a con- 
 siderably greater difference between the sexes, as in the 
 size of the canine teeth, in the development and color of 
 the hair, and especially in the color of the naked parts of 
 the skin, than in mankind. 
 
 All the secondary sexual characters of man are highly 
 variable, even within the limits of the same race; and they 
 differ much in the several races. These two rules hold 
 good generally throughout the animal kingdom. In the 
 excellent observations made on board the " Xovara,"* the 
 male Australians were found to exceed the females by only 
 sixty-five millimeters in height, while with the Javans the 
 average excess was two hundred and eighteen millimeters; 
 so that in this latter race the difference in height between the 
 sexes is more than thrice as great as with the Australians. 
 Numerous measurements were carefully made of the stat- 
 ure, the circumference of the neck and chest, the length of 
 the back-bone and of the arms, in various races; and 
 nearly all these measurements show that the males differ 
 much more from one another than do the females. This 
 fact indicates that, as far as these characters are con- 
 cerned, it is the male which has been chiefly modified, 
 since the several races diverged from their common stock. 
 
 The development of the beard and the hairiness of the 
 body differ remarkably in the men of distinct races, and 
 even in different tribes or families of the same race. We 
 Europeans sec this among ourselves. In the Island of St. 
 Kilda, according to Martin, f the men do not acquire 
 beards until the age of thirty or upward, and even 
 then the beards are very thin. On the Europseo- Asiatic 
 continent, beards prevail until we pass beyond India ; 
 though with the natives of Ceylon they are often absent, 
 as was noticed in ancient times by Diodorus.J Eastward 
 
 * The results were deduced by Dr. WeisbacL. from the measure- 
 ments made by Drs. K. Scherzer and Schwarz. See " Reise der 
 Novara :' Anthropolog. Theil," 1867, ss. 216, 231, 234, 236. 239. 269. 
 
 f "Voyage to St. Kilda" (3d edit., 1753), p. 37. 
 
 $ Sir J. E. Tennent, "Ceylon," vol. ii, 1859, p. 107.
 
 SECOND AR T SEX UAL CHAR A CTERS. 639 
 
 of India beards disappear, as with the Siamese, Malays, 
 Kalmucks, Chinese, and Japanese; nevertheless the Ainos,* 
 who inhabit the northernmost islands of the Japan Archi- 
 pelago, are the hairiest men in the world. With negroes 
 the beard is scanty or wanting, and they rarely have 
 whiskers; in both sexes the body is frequently almost des- 
 titute of fine down.f On the other hand, the Papauns of 
 the Malay Archipelago, who are nearly as black as negroes, 
 possess well-developed beards. J In the Pacific Ocean the 
 inhabitants of the Fiji Archipelago have large bushy 
 beards, while those of the not distant archipelagoes of 
 Tonga and Samoa are beardless; but these men belong to 
 distinct races. In the Ellice group all the inhabitants 
 belong to the same race; yet on one island alone, namely 
 Nunemaya, " the men have splendid beards; ' while on 
 the other islands " they have, as a rule, a dozen straggling 
 hairs for a beard. " 
 
 Throughout the great American continent the men may 
 be said to be beardless; but in almost all the tribes a few 
 short hairs are apt to appear on the face, especially in old 
 age. With the tribes of North America, Catlin estimates 
 that eighteen out of twenty men are completely destitute 
 by nature of a beard; but occasionally there may be seen a 
 a man who has neglected to pluck out the hairs at puberty, 
 with a soft beard an inch or two in length. The Guaranys 
 of Paraguay differ from all the surrounding tribes in hav- 
 ing a small beard, and even some hair on the body, but no 
 whiskers. || I am informed by Mr. D. Forbes, who par- 
 ticularly attended to this point, that the Aymaras and 
 
 * Quatref ages, "Revue des Cours Scientifiques," Aug. 29, 1868, p. 
 630; Vogt, " Lectures on Man," Eng. translat., p. 127. 
 
 fOn the beards of negroes, Vogt, " Lectures," etc., p. 127; Waitz, 
 " Introduct. to Anthropology," Eng. translat., 1863, vol. i, p. 96. It 
 is remarkable that in the United States (" Investigations in Military 
 and Anthropological Statistics of American Soldiers," 1869, p. 569), 
 the pure negroes and their crossed offspring seem to have bodies 
 almost as hairy as Europeans. 
 - % Wallace. " The Malay Arch.," vol. ii, 1869, p. 178. 
 
 Dr. J. Barnard Davis on "Oceanic Races," in " Anthropolog. 
 Review," April, 1870, pp. 185, 191. 
 
 | Catlin, " North American Indians," 3d edit., 1842,_ vol. ii, p. 227. 
 On the Guaranys, see Azara, " Voyages dans 1'Amerique Merid.," 
 torn, ii., Ib09, p. 58; also Rengger, "Saugethiere von Paraguay," 
 b. 3
 
 640 THE DESCENT OF MAN. 
 
 Quichuas of the Cordillera are remarkably hairless, yet in 
 old age a few straggling hairs occasionally appear on the 
 chin. The men of these two tribes have very little hair on 
 the various parts of the body where hair grows abundantly 
 in Europeans, and the women have none on the corre- 
 sponding parts. The hair on the head, however, attains 
 an extraordinary length in both sexes, often reaching 
 almost to the ground; and this is likewise the case with 
 some of the North American tribes. In the amount of hair 
 and in the general shape of the body the sexes of the 
 American aborigines do not differ so much from each other 
 as in most other races.* This fact is analogous with what 
 occurs with some closely allied monkeys; thus the sexes of 
 the chimpanzee are not as different as those of the orang 
 or gorilla, f 
 
 In the previous chapters we have seen that with mam- 
 mals, birds, fishes, insects, etc., many characters, which 
 there is every reason to believe were primarily gained 
 through sexual selection by one sex, have been transferred 
 to the other. As this same form of transmission has ap- 
 parently prevailed much with mankind, it will save useless 
 repetition if we discuss the origin of characters peculiar to 
 the male sex together with certain other characters com- 
 mon to both sexes. 
 
 Law of Battle. With savages, for instance, the Aus- 
 tralians, the women are the constant cause of war both 
 between members of the same tribe and between distinct 
 tribes. So no doubt it was in ancient times; "namfuitante 
 Helenam mulier teterriina belli causa." With some of the 
 North American Indians the contest is reduced to a system. 
 That excellent observer, Hearne,J says: "It has ever 
 been the custom among these people for the men to wrestle 
 
 *Prof. and Mrs. Agassiz ("Journey in Brazil," p. 530), remark 
 that the sexes of the American Indians differ less than those of the 
 negroes and of the higher races. See also Rengger, ibid., p. 3, on 
 the Guaranys. 
 
 f Riitimeyer, "Die Grenzen der Thierwelt; eine Betrachtung zu 
 Darwin's Lehre," 1868, s. 54. 
 
 $"A Journey from Prince of Wales Fort.," 8vo. edit., Dublin, 
 1796, p. 104. Sir J. Lubbock ("Origin of Civilization," 1870, p. 69), 
 gives other and similar cases in North America. For the Guanas of 
 South America see Azara, "Voyages, "etc., torn, ii, p. 94.
 
 SECONDARY SEXUAL CHARACTERS. 641 
 
 for any woman to whom they are attached; and, of course, 
 the strongest party always carries off the prize. A weak man, 
 unless he be a good hunter and well beloved, is seldom per- 
 mitted to keep a wife that a stronger man thinks worth his 
 notice. This custom prevails throughout all the tribes, 
 and causes a great spirit of emulation among their youth, 
 who are upon all occasions, from their childhood, trying 
 their strength and skill in wrestling." With the Guanas 
 of South America, Azara states that the men rarely marry 
 till twenty years old or more, as before that age they cannot 
 conquer their rivals. 
 
 Other similar facts could be given; but even if we had 
 no evidence on this head we might feel almost sure, from 
 the analogy of the higher Quadrumana,* that the law of 
 battle had prevailed with man during the early stages of 
 his development. The occasional appearance at the pres- 
 ent day of canine teeth which project above the others, 
 with traces of a diastema or open space for the reception of 
 the opposite canines, is in all probability a case of reversion to 
 a former state, when the progenitors of man were provided 
 with these weapons, like so many existing male Quadrumana. 
 It was remarked in a former chapter that as man gradually 
 became erect, and continually used his hands and arms 
 for fighting with sticks and stones, as well as for the other 
 purposes of life, he would have used his jaws and teeth 
 less and less. The jaws, together with their muscles, would 
 then have been reduced, through disuse, as would the teeth 
 through the not well understood principles of correlation 
 and economy of growth; for we everywhere see that parts, 
 which are no longer of service, are reduced in size. By such 
 steps the original inequality between the jawa and teeth 
 in the two sexes of mankind would ultimately have been 
 obliterated. The case is almost parallel with that of many 
 male ruminants, in which the canine teeth have been 
 reduced to mere rudiments, or have disappeared, apparently, 
 in consequence of the development of horns. As the prodig- 
 ious difference between the skulls of the two sexes in the 
 orang and gorilla stands in close relation with the develop- 
 ment of the immense canine teeth in the males, we may 
 infer that the reduction of the jaws and teeth in the early 
 
 *0n the fighting of the male gorillas, see Dr. Savage, in "Boston 
 Journal of Nat. Hist.," vol v., 1847, p. 423. On Presbytia entellus, 
 see the "Indian Field," 1859, p. 146.
 
 642 THE DESCENT OF MAN. 
 
 male progenitors of man must have led to a most striking 
 and favorable change in his appearance. 
 
 There can be little doubt that the greater size and 
 strength of man, in comparison with woman, together with 
 his broader shoulders, more developed muscles, rugged out- 
 line of body, his greater courage and pugnacity are all due 
 in chief part to inheritance from his ha!f- human male ances- 
 tors. These characters would, however, have been preserved 
 or even augmented during the long ages of man's savagery, 
 by the success of the strongest and boldest men, both in the 
 general struggle for life and in their contests for wives; a suc- 
 cess which would have insured their leaving a more numer- 
 ous progeny than their less favored brethren. It is not proba- 
 ble that the greater strength of man was primarily acquired 
 through the inherited effects of his having worked harder 
 than woman for his own subsistence and that of his family; 
 for the women in all barbarous nations are compelled 
 to work at least as hard as the men. With civilized 
 people the arbitrament of battle for the possession of the 
 women has long ceased; on' the other hand, the men, as a 
 general rule, have to work harder than the women for their 
 Joint subsistence, and thus their greater strength will have 
 been kept up. 
 
 Difference in the Mental Powers of the Two Sexes. With 
 respect to differences of this nature between man and 
 woman it is probable that sexual selection has played a 
 highly important part. I am aware that some writers 
 doubt whether there is any such inherent difference ; but 
 this is at least probable from the analogy of the lower ani- 
 mals which present other secondary sexual characters. No 
 one disputes that the bull differs in disposition from the 
 cow, the wild-boar from the sow, the stallion from the 
 mare, and, as is well known to the keepers of menageries, 
 the males of the larger apes from the females. Woman 
 seems to differ from man in mental disposition, chiefly in 
 her greater tenderness and less selfishness; and this holds 
 good even with savages, as shown by a well-known passage 
 in " Mungo Park's Travels," and by statements made by 
 many other travelers. Woman, owing to her maternal 
 instincts, displays these qualities toward her infant in an 
 eminent degree; therefore it is likely that she would often 
 extend them toward her fellow-creatures. Man is the rival
 
 SECONDARY SEXUAL CHARACTERS. 643 
 
 of other men; he delights in competition, and this leads to 
 ambition which passes too easily into selfishness. These 
 latter qualities seem to be his natural and unfortunate 
 birthright. It is generally admitted that with woman the 
 powers of intuition, of rapid perception, and perhaps of 
 imitation, are more strongly marked than in man; but 
 some, at least, of these faculties are characteristic of the 
 .lower races, and, therefore, of a past and lower state of 
 civilization. 
 
 The chief distinction in the intellectual powers of the 
 two sexes is shown by man's attaining to a higher eminence, 
 in whatever he takes up, than can woman whether requir- 
 ing deep thought, reason, or imagination, or merely the 
 use of the senses and hands. If two lists were made of the 
 most eminent men and women in poetry, painting, sculpt- 
 ure, music (inclusive both of composition and perform- 
 ance), history, science and philosophy, with half a dozen 
 names under each subject, the two lists would not bear 
 comparison. We may also infer, from the law of the devia- 
 tion from averages, so well illustrated by Mr. Galton, in 
 his work on " Hereditary Genius/' that if men are capable 
 of a decided pre-eminence over women in many subjects, 
 the average of mental power in man must be above that of 
 woman. 
 
 Among the half-human progenitors of man, and among 
 savages, there have been struggles between the males during 
 many generations for the possession of the females. But 
 mere bodily strength and size would do little for victory, 
 unless associated with courage, perseverence and deter- 
 mined energy. With social animals the young males have 
 to pass through many a contest before they win a female, 
 and the older males have to retain their females by renewed 
 battles. They have, also, in the case of mankind, to 
 defend their females, as well as their young, from enemies 
 of all kinds, and to hunt for their joint subsistence. But 
 to avoid enemies or to attack them with success, to capture 
 wild animals, and to fashion weapons, requires the aid of 
 the higher mental faculties, namely, observation, reason, 
 invention, or imagination. These various faculties will 
 thus have been continually put to the test and selected 
 during manhood; they will, moreover, have been strength- 
 ened by use during this same period of life. Consequently, 
 in accordance witli the urincipJ often alluded to, we
 
 644 THE DESCENT OF MAN. 
 
 might expect that they would at least tend to be trans- 
 mitted chiefly to the male offspring at the corresponding 
 period of manhood. 
 
 Now, when two men are put into competition, or a man 
 with a woman, both possessed of every mental quality in 
 equal perfection, save that one has higher energy, perse- 
 verance and courage, the latter will generally become more 
 eminent in every pursuit and will gain the ascendency.* 
 He may be said to possess genius for genius has been de- 
 clared by a great authority to be patience; and patience, in 
 this sense, means unflinching, undaunted perseverance. 
 But this view of genius is perhaps deficient; for without 
 the aigher powers of the imagination and reason, no 
 eminent success can be gained in many subjects. These 
 latter faculties, as well as the former, will have been de- 
 veloped in man, partly through sexual selection that is, 
 through the contest of rival males, and partly through 
 natural selection that is, from success in the general 
 struggle for life; and as in both cases the struggle will have 
 been during maturity, the characters gained will have been 
 transmitted more fully to the male than to the female off- 
 spring. It accords in a striking manner with this view of 
 the modification and re-enforcement of many of our 
 mental faculties by sexual selection, that, firstly, they 
 notoriously undergo a considerable change at puberty, f 
 and, secondly, that eunuchs remain throughout life inferior 
 in these same qualities. Thus man has ultimately become 
 superior to woman. It is, indeed, fortunate that the law 
 of the equal transmission of characters to both sexes pre- 
 vails with mammals ; otherwise it is probable that man 
 would have become as superior in mental endowment to 
 woman, as the peacock is in ornamental plumage to the 
 peahen. 
 
 It must be borne in mind that the tendency in char- 
 acters acquired by either sex late in life, to be transmitted 
 to the same sex at the same age, and of early acquired 
 characters to be transmitted to both sexes, are rules which, 
 though general, do not always hold. If they always held 
 
 *J. Stuart Mill remarks (" The Subjection of Women," 1869, p. 
 122); ' The things in which man most excels woman are those which 
 require most plodding, and long hammering at single thoughts. " 
 What is this but energy and perseverance ? 
 
 f Maudsley, "Mind and Body
 
 SECONDARY SEXUAL CHARACTERS. 645 
 
 good, we might conclude (but I here exceed my proper 
 bounds) that the inherited effects of the early education of 
 boys and girls would be transmitted equally to both sexes; 
 so that the present inequality in mental power between the 
 sexes would not be effaced by a similar course of early 
 training; nor can it have been caused by their dissimilar 
 early training. In order that woman should reach the 
 same standard as man, she ought, when nearly adult, to be 
 trained to energy and perseverance and to have her reason 
 and imagination exercised to the highest point; and then 
 she would probably transmit these qualities chiefly to her 
 adult daughters. All women, however, could not be thus 
 raised, unless during many generations those who excelled 
 in the above robust virtues were married and produced off- 
 spring in larger numbers than other women. As before 
 remarked of bodily strength, although men do not now 
 fight for their wives, and this form of selection has passed 
 away, yet during manhood they generally undergo a severe 
 struggle in order to maintain themselves and their families; 
 and this will tend to keep up or even increase their mental 
 powers, and, as a consequence, the present inequality be- 
 tween the sexes.* 
 
 Voice and Musical Powers. In some species of Quadru- 
 mana there is a great difference between the adult sexes, 
 in the power of their voices and in the development of 
 the vocal organs; and man appears to have inherited this 
 difference from his early progenitors. His vocal cords are 
 about one-third longer than in woman, or than in boys ; 
 and emasculation produces the same effect on him as on 
 the lower animals, for it "arrests that prominent growth of 
 the thyroid, etc., which accompanies the elongation of the 
 cords, "f With respect to the cause of this difference 
 between the sexes, I have nothing to add to the remarks in 
 
 * An observation by Vogt bears on this subject: he says, " It is a 
 remarkable circumstance, that the differences between the sexes, as 
 regards the cranial cavity, increases with the development of the 
 race, so that the male European excels much more the female, than 
 the negro the negress. Welcker confirms this statement of Huschke 
 from his measurements of negro and German skulls." But Vogt 
 admits (" Lectures on Man," Eng. translat., 1864, p. 81) that more 
 observations are requisite on this point. 
 
 f Owen, "Anatomy of Vertebrates," vol. iii, p. 603.
 
 646 THE DESCENT OF MAN. 
 
 the last chapter on the probable effects of the long-contin- 
 ued use of the vocal organs by the male under the excite- 
 ment of love, rage and jealousy. According to Sir Duncan 
 Gibb,* the voice and the form of the larynx differ in the 
 different races of mankind; but with the Tartars, Chinese, 
 etc., the voice of the male is said not to diifer so much 
 from that of the female, as in most other races. 
 
 The capacity and love for singing or music, though not 
 a sexual character in man, -must not here be passscl over. 
 Although the sounds emitted by animals of all kinds 
 serve many purposes, a strong case can be made out, that 
 the vocal organs were primarily used and perfected in rela- 
 tion to the propagation of the species. Insects and some 
 few spiders are the lowest animals which voluntarily pro- 
 duce any sound; and this is generally effected by the aid of 
 beautifully constructed stridulating organs, which are often 
 confined to the males. The sounds thus produced consist, 
 I believe in all cases, of the same note, repeated rhythmi- 
 cally;! and this is sometimes pleasing even to the ears of 
 man. The chief and, in some cases, exclusive purpose 
 appears to be either to call or charm the opposite sex. 
 
 The sounds produced by fishes are said in some cases to 
 be made only by the males during the breeding-season. All 
 the air-breathing Vertebrata necessarily possess an appa- 
 ratus for inhaling and expelling air, with a pipe capable of 
 being closed at one end. Hence when the primeval mem- 
 bers of this class were strongly excited and 'their muscles 
 violently contracted, purposeless sounds would almost cer- 
 tainly have been produced; and these, if they proved in 
 any way serviceable, might readily have been modified or 
 intensified by the preservation of properly adapted vari- 
 ations. The lowest Vertebrates which breathe air are 
 Amphibians; and of these, frogs and toads possess vocal 
 organs, which are incessantly used during the breeding- 
 season, and which are often more highly developed in the 
 male than in the female. The male alone of the tortoise 
 utters a noise, and this only during the season of love. 
 Male alligators roar or bellow during the same season. 
 Every one knows how much birds use their vocal organs as 
 
 '"Journal of the Antliropolog. Soc.," April, 1869, pp. 57, 66. 
 fDr. Scudder, "Notes on Striduiation," in " Proc. Boston Soc. of 
 Nat. Hist., "vol. xi, April, 1868.
 
 SECONDARY SEXUAL CHARACTERS, 617 
 
 a means of courtship; and some species lik#i* perform 
 what may be called instrumental music. 
 
 In the class of mammals, with which we are iiere more 
 particularly concerned, the males of alxnokt all the species 
 use their voices during the breeding-season much more 
 than at any other time ; and some are absolutely mute 
 excepting at this season. With otner species both sexes, 
 or only the females, use their voices as a love-call. Con- 
 sidering these facts, and that the vocal organs of some 
 quadrupeds are much more largely developed in the male 
 than in the female, either permanently or temporarily, 
 during the breed ing-season; and considering that in most 
 of the lower classes the sounds produced by the males serve 
 not only to call but to excite or allure the female; it is a 
 surprising fact that we have not as yet any good evidence 
 that these organs are used by male mammals to charm the 
 females. The American Mycetes caraya perhaps forms an 
 exception, as does the Hylobates agilis, an ape allied to 
 man. This gibbon has an extremely loud but musical 
 voice. Mr. Waterhouse states,* " It appeared to me that 
 in ascending and descending the scale the intervals were 
 always exactly half-tones; and I am sure that the highest 
 note was the exact octave to the lowest. The quality of the 
 notes is very musical; and I do not doubt that a good 
 violinist would be able to give a correct idea of the gibbon's 
 composition, excepting as regards its loudness." Mr. 
 Waterhouse then gives the notes. Prof. Owen, who is a 
 musician, confirms the foregoing statement, and remarks, 
 though erroneously, that this gibbon, "alone of brute 
 mammals,' may be said to sing." It appears to be much 
 excited after its performance. Unfortunately, its habits 
 have never been closely observed in a state of nature; but 
 from the analogy of other animals, it is probable that it 
 uses its musical powers more especially during the season 
 of courtship. 
 
 This gibbon is not the only species in the genus which 
 sings, for my -son, Francis Darwin, attentively listened in 
 "the Zoological Gardens to H. leuciscus while singing a 
 cadence of three notes, in true musical intervals and with 
 a clear musical tone. It is a more surprising fact that 
 
 * Given in W. C. L. Martin's " General Introduction to Nat. Hist, 
 of Mamm. Animals," 1841, \>. 482: Owen "Anatomy of Vertebrates/' 
 vol. iii, p. 600.
 
 $4 THE DESCENT OF MAN, 
 
 certain rodents utter musical sounds. Singing mice have 
 often been mentioned and exhibited, but imposture has 
 commonly been suspected. We have, however, at last a 
 clear account by a well-known observer, the Eev. S. Lock- 
 wood,* of the musical powers of an American species, the 
 Hesperomys cognatus, belonging to a genus distinct from 
 that of the English mouse. This little animal was kept in 
 confinement, and the performance was repeatedly heard. 
 In one of the two chief songs, " the last bar would fre- 
 quently be prolonged to two or three; and she would some- 
 times change from C sharp and D to C natural and D, then 
 warble on. these two notes awhile, and wind up with a quick 
 chirp on C sharp and D. The distinctness between the 
 semitones was very marked and easily appreciable to a 
 good ear." Mr. Lockwood gives both songs in musical 
 notation; and adds that though this little mouse "had no 
 ear for time, yet she would keep to the key of B (two flats) 
 and strictly in a major key. . .. . Her soft clear 
 voice falls an octave with all the precision possible; then at 
 the wind-up it rises again into a quick trill on C sharp 
 and D." 
 
 A critic has asked how the ears of man, and he ougnt to 
 have added of other animals, could have been adapted by 
 selection so as to distinguish musical notes. But this 
 question shows some confusion on the subject; a noise is the 
 sensation resulting from the co-existence of several aerial 
 "simple vibrations" of various periods, each of which 
 intermits so frequently that its separate existence cannot be 
 perceived. It is only in the want of continuity of such 
 vibrations, and in their want of harmony inter se, that a noise 
 differs from a musical note. Thus an ear to be capable of 
 discriminating noises and the high importance of this 
 power to all animals is admitted by every one must be 
 sensitive to musical notes. We have evidence of this 
 capacity even low down in the animal scale; thus Crusta- 
 ceans are provided with auditory hairs of different lengths, 
 which have been seen to vibrate when the proper musical 
 notes are struck, f As stated in a previous chapter, similar 
 observations have been made on the hairs of the antennae 
 of gnats. It has been positively asserted by good observers 
 
 *The "American Naturalist," 1871, p. 761. 
 
 iHelmholtz, " Tkeorie Phys. de 1* Musique," 1868, p. 187.
 
 SECOND AR T SEX U A L CHARACTERS. 649 
 
 that spiders are attracted by music. It is also well known 
 that some dogs howl when hearing particular tones.* Seals 
 apparently appreciate music, and their fondness for it 
 " was well known to the ancients, and is often taken 
 advantage of by the hunters at the present day."f 
 
 Therefore, as far as the mere perception of musical 
 notes is concerned, there seems no special difficulty in the 
 case of man or of any other animal. Helmholtz has explained 
 on physiological principles why concords are agreeable and 
 discords disagreeable to the human ear; but we are little 
 concerned with these, as music in harmony is a late inven- 
 tion. We are more concerned with melody, and here 
 again, according to Helmholtz, it is intelligible why the 
 notes of our musical scale are used. The ear analyzes all 
 sounds into their component " simple vibrations," although 
 we are not conscious of this analysis. In a musical note 
 the lowest in pitch of these is generally predominant, and 
 the others which are less marked are the octave, the 
 twelfth, the second octave, etc., all harmonies of the 
 fundamental predominant note; any two notes of our scale 
 have many of these harmonic over-tones in common. It 
 seems pretty clear, then, that if an animal always wished 
 to sing precisely the same song, he would guide himself by 
 sounding those notes in succession which possess many 
 over-tones in common that is, he would choose for his 
 song notes which belong to our musical scale. 
 
 But if it be further asked why musical tones in a certain 
 order and rhythm give man and other animals pleasure, we 
 can no more give the reason than for the pleasantness of 
 certain tastes and smells. That they do give pleasure of 
 some kind to animals we may infer from their being pro- 
 duced during the season of courtship by many insects, 
 spiders, fishes, amphibians and birds ; for unless the 
 females were able to appreciate such sounds and were 
 excited or charmed by them, the persevering efforts of the 
 males, and the complex structures often possessed by them 
 alone, would be useless ; and this it is impossible to 
 believe.- 
 
 * Several accounts have been published to this effect. Mr. Peach 
 writes to me that he has repeatedly found that an old dog of his 
 howls when B flat is sounded on the flute, and to no other note. I 
 Biay add another instance of a dog always whining, when one note 
 on a concertina, which was out of tune, was played. 
 
 fMr. R. Brown, in "Proc. Zool. Soc.." 1868, p. 410.
 
 650 THE DESCENT OF MAN. 
 
 Human song is generally admitted to be the basis or 
 origin of instrumental music. As neither the enjoyment 
 nor the capacity of producing musical notes are faculties 
 of the least use to man in reference to his daily habits of 
 life, they must be ranked among the most mysterious with 
 which he is endowed. They are present, though in a very 
 rude condition, in men of all races, even the most savage; 
 but so different is the taste of the several races that our 
 music gives no pleasure to savages, and their music is to us 
 in most cases hideous and unmeaning. Dr. Seemann, in 
 some interesting remarks on this subject,* " doubts 
 whether even among the nations of Western Europe, 
 intimately connected as they are by close and frequent 
 intercourse, the music of the one is interpreted in the same 
 sense by the others. By traveling eastward we find that 
 there is certainly a different language of music. Songs of 
 joy and dance accompaniments are no longer, as with us, 
 in the major keys, but always in the minor." Whether or 
 not the half -human progenitors of man possessed, like the 
 singing gibbons, the capacity of producing, and, therefore, 
 no doubt of appreciating, musical notes, we know that 
 man possessed these faculties at a very remote period. M. 
 Lartet has described two flutes made out of the bones and 
 horns of the reindeer, found in caves together with flint 
 tools and the remains of extinct animals. The arts of 
 singing and of dai?cing are also very ancient, and arc now 
 practiced by all or nearly all the lowest races of man. 
 Poetry, which may be considered as the offspring of song, 
 is likewise so ancient that many persons have felt astonished 
 that it should have arisen during the earliest ages of which 
 \ve have any record. 
 
 We see that the musical faculties, which are not wholly 
 deficient in any race, are capable of prompt and high 
 development, for Hottentots and negroes have become 
 excellent musicians, although in their native countries 
 they rarely practice anything that we should consider 
 music. Schweinfurth, however, was pleased with some of 
 the simple melodies which he heard in the interior of 
 Africa. But there is nothing anomalous in the musical 
 
 * "Journal of Anthropolog. Soc.," Oct., 1870, p. 155. See also the 
 several later chapters in Sir John Lubbock's " Prehistoric Times," 
 second edition, 1869, which contain an admirable account of the 
 habits of savages. - -
 
 SECONDARY SEXUAL CHARACTERS. 651 
 
 faculties lying dormant in man; some species of birds 
 which never naturally sing, can without much difficulty be 
 taught to do so; thus a house-sparrow has learned the song 
 of a linnet. As these two species are closely allied and 
 belong to the order of Insessores, which includes nearly all 
 the singing-birds in the world, it is possible that a pro- 
 genitor of the sparrow may have been a songster. It is 
 more remarkable that parrots, belonging to a group distinct 
 from the Insessores, and having differently constructed 
 vocal organs, can be taught not only to speak, but to pipe 
 or whistle tunes invented by man, so that they must have 
 some musical capacity. Nevertheless, it would be very rash 
 to assume that parrots are descended from some ancient 
 form which was a songster. Many cases could be advanced 
 of organs and instincts originally adapted for one purpose, 
 having been utilized for some distinct purpose.* Hence 
 the capacity for high musical development which the 
 savage races of man possess, may be due either to the prac- 
 tice by our semi-human progenitors of some rude form of 
 music, or simply to their having acquired the proper vocal 
 organs for a different purpose. But in this latter case we 
 must assume, as in the above instance of parrots, and as 
 seems to occur with many animals, that they already pos- 
 sessed some sense of melody. 
 
 Music arouses in us various emotions, but not the more 
 terrible ones of horror, fear, rage, etc. It awakens the 
 gentler feelings of tenderness and love, which readily pass 
 into devotion. In the Chinese annals it is said: " Music 
 hath the power of making heaven descend upon earth/'' 
 It likewise stirs up in us the sense of triumph and the 
 glorious ardor for war These powerful and mingled feel- 
 ings may well give rise to the sense of sublimity. We can 
 concentrate, as Dr. Seamarm observes, greater intensity of 
 feeling in a single musical note than in pages of writing. 
 
 * Since this chapter was printed, I have seen a valuable article by 
 Mr. Chauncy Wright (" North American Review," Oct., 1870, p. 
 293), who, in discussing the above subject, remarks: " There are 
 many consequences of the ultimate laws or uniformities of nature, 
 through which the acquisition of one useful power will bring with it 
 many resulting advantages as well as limiting disadvantages, actual 
 or possible, which the principle of utility may not have comprehended 
 in its actions." As I have attempted to show in an early chapter of 
 this work, this principle has an important bearing on the acquisition 
 by man of some of his mental characteristics.
 
 652 THE DESCENT OF MAN. 
 
 It is probable that nearly the same emotions, but muok 
 weaker and far less complex, are felt by birds when the 
 male pours forth his full volume of song, in rivalry with 
 other males, to captivate the female. Love is still the 
 commonest theme of our songs. As Herbert Spencer re- 
 marks, " music arouses dormant sentiments of which we 
 had not conceived the possibility, and do not know the 
 meaning; or, as Eichter says, tells us of things we have not 
 seen and shall not see." Conversely, when vivid emotions 
 are felt and expressed by the orator, or even in common 
 ispeech, musical cadences and rhythm are instinctively used. 
 [The negro in Africa when excited often bursts forth in 
 song; "another will reply in song, while the company, as 
 if touched by a musical wave, murmur a chorus in perfect 
 unison."* Even monkeys express strong feelings in dif- 
 ferent tones anger and impatience by low, fear and pain 
 by high notes, f The sensations and ideas thus excited in 
 us by music, or expressed by the cadences of oratory, appear 
 from their vagueness, yet depth, like mental reversions to 
 the emotions and thoughts of a long past age. 
 
 All these facts with respect to music and impassioned 
 speech become intelligible to a certain extent, if we may 
 assume that musical tones and rhythm were used by our 
 half-human ancestors, during the season of courtship, 
 when animals of all kinds are excited not only by love, but 
 by the strong passions of jealousy, rivalry, and triumph. 
 From the deeply laid principle of inherited associations, 
 musical tones in this case would be likely to call up 
 vaguely and indefinitely the strong emotions of a long-past 
 age. As we have every reason to suppose that articulate 
 speech is one of the latest, as it certainly is the highest, of 
 the arts acquired by man, and as the instinctive power of 
 producing musical notes and rhythms is developed low 
 down in the animal series, it would be altogether opposed 
 to the principle of evolution, if we were to admit that 
 man's musical capacity has been developed from the tones 
 used in impassioned speech. We must suppose that the 
 rhythms and cadences of oratory are derived from previously 
 
 *Winwood Reade, "The Martyrdom of Man," 1872, p. 441, and 
 "African Sketch-book," 1873, vol. ii, p. 313. 
 f Rengger, ' ' Sftugethiere von Paraguay, " s. 49.
 
 SECONDARY SEXUAL CHARACTERS. 653 
 
 developed musical powers.* We can thus understand how 
 it is that music, dancing, song, and poetry are such very 
 ancient arts. "We may go even further than this, and, as 
 remarked in a former chapter, believe that musical sounds 
 afforded one of the bases for the development of language, f 
 As the males of several quadrumanous animals have their 
 vocal organs much more developed than in the females, and 
 as a gibbon, one of the anthropomorphous apes, pours 
 forth a whole octave of musical notes and may be said to 
 sing? it appears probable that the progenitors of man, 
 either the males or females or both sexes, before acquiring 
 the power of expressing their mutual love in articulate 
 language, endeavored to charm each other with musical 
 notes and rhythm. So little is known about the use of the 
 voice by the Quadrumana during the season of love, that 
 we have no means of judging whether the habit of singing 
 was first acquired by our male or female ancestors. Women 
 are generally thought to possess sweeter voices than men, 
 and as far as this serves as any guide, we may infer that 
 they first acquired musical powers in order to attract the 
 other sex. | But, if so, this must have occured long ago, 
 before our ancestors had become sufficiently human to treat 
 and value their women merely as useful slaves. The impas- 
 
 *See the very interesting discussion on the " Origin and Function 
 of Music," by Mr. Herbert Spencer, in his collected "Essays," 1858, 
 p. 359. Mr. Spencer comes to an exactly opposite conclusion to that 
 at which I have arrived. He concludes, as did Diderot formerly, 
 that the cadences used in emotional speech afford the foundation 
 from which music has been developed; while I conclude that musical 
 notes and rhythms were first acquired by the male or female progen- 
 itors of mankind for the sake of charming the opposite sex. Thus 
 musical tones became firmly associated with some of the strongest 
 passions an animal is capable of feeling, and are consequently used 
 instinctively, or through association when strong emotions are 
 expressed in speech. Mr. Spencer does not offer any satisfactory 
 explanation, nor can I, why high or deep notes should be expressive, 
 both with man and the lower animals, of certain emotions. Mr. 
 Spencer gives also an interesting discussion on the relations between 
 poetry, recitative and song. 
 
 f I find in Lord Monboddo's "Origin of Language," vol. i, (1774), 
 p. 469, that Dr. Blacklock likewise thought "that the first language 
 among men was music, and that before our ideas were expressed by 
 articulate sounds they were communicated by tones varied according 
 to different degrees of gravity and acuteness." 
 
 See an interesting discussion on this subject, by Hackel. "(Jenqr- 
 elle Morph," B. ii, 1866, s. 246.
 
 654 THE DESCENT OF MAN. 
 
 stoned orator, bard, or musician, when with his varied 
 tones and cadences he excites the strongest emotions in his 
 hearers, little suspects that he uses the same means by 
 which his half-human ancestors long ago aroused each 
 other's ardent passions, during their courtship and rivalry. 
 
 The Influence of Beauty in Determining the Marriages 
 of Mankind. In civilized life man is largely, but by no 
 means exclusively, influenced in the choice of bis wife by 
 external appearance; but we are chiefly concerned with 
 primeval times, and our only means of forming a judgment 
 on this subject is to study the habits of existing semi- 
 civilized and savage nations. If it can be shown that the 
 men of different races prefer women having various char- 
 acteristics, or conversely with the women, we have then to 
 inquire whether such choice, continued during many gene- 
 rations, would produce any sensible effect on the race, 
 either on one sex or both, according to the form of inherit- 
 ance which has prevailed. 
 
 It will be well first to show in some detail that savages 
 y the greatest attention to their personal appearance.* 
 at they have a passion for ornament is notorious; and an 
 English philosopher goes so far as to maintain that clothes 
 were first made for ornament and not for warmth. As 
 Prof. Waitz remarks: " however poor and miserable man 
 is he finds a pleasure in adorning himself." The extrava- 
 gance of the naked Indians of South America in decorat- 
 ing themselves is shown " by a man of large stature gain- 
 ing with difficulty enough by the labor of a fortnight to 
 procure in exchange the chica necessary to paint himself 
 red."f The ancient barbarians of Europe, during the 
 
 * A full and excellent account of the manner In which savages in 
 all parts of the world ornament themselves, is given by the Italian 
 traveler, Prof. Mantegazza, "Rio de la Plata, Viaggi e Studi," 
 1867, pp. 525-545 ; all the following statements, when other refer- 
 ences are not given, are taken from this work. See, also, Waitz, 
 "Introduction to Anthropolog.," Eng. translat., vol. i, 1863, p. 275, 
 et passim. Lawrence also gives very full details in his "Lectures 
 on Physiology," 1822. Since this chapter was written Sir J. Lub- 
 bock has published his "Origin of Civilization," 1870, in which 
 there is an interesting chapter on the present subject, and from 
 which (pp. 42, 48) I have taken some facts about savages dyeing 
 their teeth and hair and piercing their teeth. 
 
 f Humboldt, "Personal Narrative," Eng. translat., vol. iv, p. 515; 
 on the imagination shown in painting the body, p. 522; on modifying 
 the form of, the calf of the ley jp. 466. 
 
 pa 
 T
 
 SECONDARY SEXUAL CHARACTERS. 655 
 
 Reindeer period, brought to their caves any- brilliant or 
 singular objects which they happened to find. Savages at 
 the present day everywhere deck themselves with plumes, 
 necklaces, armlets, ear-rings, etc. They paint themselves 
 in the most diversified manner. " If painted nations," as 
 Humbolclt observes, "had been examined with the same 
 attention as clothed nations, it would have been perceived 
 that the most fertile imagination and the most mutable 
 caprice have created the fashions of painting, as well as 
 those of garments." 
 
 In one part of Africa the eyelids are colored black; in 
 another the nails are colored yellow or purple. In many 
 places the hair is dyed of various tints. In different coun- 
 tries the teeth are stained black, red, blue, etc., and in 
 the Malay Archipelago it is thought shameful to have white 
 teeth, " like those of a dog." Not one great country can 
 be named, from the Polar regions in the north to New 
 Zealand in the south, in which the aborigines do not tattoo 
 themselves. This practice was followed by the Jews of old, 
 and by the ancient Britons. In Africa some of the natives 
 tattoo themselves, but it is a much more common practice 
 to raise protuberances by rubbing salt into incisions made 
 in various parts of the body; and these are considered by 
 the inhabitants of Kordofan and Darfur "to be great per- 
 sonal attractions." In the Arab countries no beauty can 
 be perfect until the cheeks " or temples have been gashed."* 
 In South America, as Humboldt remarks, "a, mother would 
 be accused of culpable indifference toward her children if 
 she did not employ artificial means to shape the calf of the 
 leg after the fashion of the country." In the Old and New 
 Worlds the shape of the skull was formerly modified during 
 infancy in the most extraordinary manner, as is still the 
 case in many places, and such deformities are considered 
 ornamental. For instance, the savages of Colombiaf 
 deem a much flattened head " an essential point of beauty." 
 
 The hair is treated with especial care in various countries; 
 it is allowed to grow to full length, so as to reach to the 
 ground, or is combed into "a compact frizzled mop, which 
 
 * " The Nile Tributaries," 1867; " The Albert N'yanza," 1866, vol. 
 i, p. 218. 
 
 4 Quoted by Prichard. " Pliys. Hist, of Mankind," 4th edit., vol. i, 
 1851, p. 331.
 
 656 THE DESCENT OF MAN. 
 
 is the Papuan's pride and glory."* In Northern Africa " a 
 man requires a period of from eight to ten years to perfect 
 his coiffure." With other nations the head is shaved, and in 
 parts of South America and Africa even the eyebrows and 
 eyelashes are eradicated. The natives of the Upper Nile 
 knock out the four front teeth, saying that they do not 
 wish to resemble brutes. Farther south the Batokas knock 
 out only the two upper incisors, which, as Livingstonef 
 remarks, gives the face a hideous appearance, owing to the 
 prominence of the lower jaw; but these people think the 
 presence of the incisors most unsightly, and on beholding 
 some Europeans, cried out: " Look at the great teeth !" 
 The chief Sebituani tried in vain to alter this fashion. In 
 various parts of Africa and in the Malay Archipelago the 
 natives file the incisors into points like those of a saw, or 
 pierce them with holes, into which they insert studs. 
 
 As the face with us is chiefly admired for its beauty, so 
 with savages it is the chief seat of mutilation. In all 
 quarters of the world the septum, and more rarely the 
 wings of the nose are pierced; rings, sticks, feathers and 
 other ornaments being inserted into the holes. The ears are 
 everywhere pierced and similarly ornamented, and with the 
 Botocudos and Lenguas of South America the hole is 
 gradually so much enlarged that the lower edge touches 
 the shoulder. In North and South America and in Africa 
 either the upper or lower lip is pierced; and with the Boto- 
 cudos the hole in the lower lip is so large that a disk of wood, 
 four inches in diameter, is placed in it. Maiitegazza gives 
 a curious account of the shame felt by a South American 
 native, and of the ridicule which he excited, when he sold his 
 tembeta the large colored piece of wood which is passed 
 through the hole. In Central Africa the women perforate 
 the lower lip and wear a crystal, which, from the movement 
 of the tongue, has " a wriggling motion, indescribably ludi- 
 crous during conversation." The wife of the chief of Latooka 
 told Sir S. Baker, \ that Lady Baker " would be much im- 
 proved if she would extract her four front teeth from the 
 lower jaw and wear the long-pointed polished crystal in her 
 
 *0n the Papuans, Wallace, "The Malay Archipelago," vol. ii, p. 
 445. On the coiffure of the Africans, Sir S. Baker, "The Albert 
 N'yanza," vol. i, p. 210. 
 
 f "Travels, "p. 533. 
 
 i " The Albert N'yanza," 1866, vol. i, p. 217.
 
 SECONDARY SEXUAL CHARACTERS. 657 
 
 under lip." Farther south with the Makalolo, the upper 
 lip is perforated, and a large metal and bamboo ring, called 
 apelele, is worn in the hole. " This caused the lip in one case 
 to project two inches beyond the tip of the nose; and when 
 the lady smiled the contraction of the muscles elevated 
 it over the eyes. ' Why do the women wear these tilings?' 
 the venerable chief, Chinsurdi, was asked. Evidently sur- 
 prised at such a stupid question, he replied: ' For beauty . 
 They are the only beautiful things women have; men have 
 beards, women have none. What kind of a person would 
 she be without the pelele? She would not be a woman at 
 all with a mouth like a man, but no beard.' "* 
 
 Hardly any part of the body, which can be unnaturally 
 modified, has escaped. The amount of suffering thus 
 caused must have been extreme, for many of the operations 
 require several years for their completion, so that the idea 
 of their necessity must be imperative. The motives are 
 various; the men paint their bodies to make themselves 
 appear terrible in battle; certain mutilations are connected 
 with religious rites, or they mark the age of puberty, or the 
 rank of the man, or they serve to distinguish the tribes. 
 Among savages the same fashions prevail for long periods, f 
 and thus mutilations, from whatever cause first made, soon 
 come to be valued as distinctive marks. But self-adorn- 
 ment, vanity and the admiration of others seem to be the 
 commonest motives. In regard to tattooing, I was told by 
 the missionaries in New Zealand that when they tried to 
 persuade some girls to give up the practice they answered: 
 " We must just have a few lines on our lips; else when we 
 grow old we shall be so very ugly." With the men of New 
 Zealand, a most capable judge J says: " To have fine 
 tattoed faces was the great ambition of the young, both to 
 render themselves attractive to the ladies and conspicuous 
 in war." A star tattooed on the forehead and a spot on 
 
 * Livingstone, "British Association," 1860; report given in the 
 "Athenaeum," July 7, 1860, p. 29. 
 
 - fSir-6. Baker (ibid., vol. i, p. 210) speaking of the natives of 
 Central Africa, says: " Every tribe has a distinct and unchanging 
 fashion for dressing the hair." See Agassiz ("Journey in Brazil," 
 1868, p. 318) on the invariability of the tattooing of the Amazonian 
 Indians. 
 
 JRev. R. Taylor, "New Zealand and Its Inhabitants," 1855, p. 
 152.
 
 658 THE DESCENT OF MAN. 
 
 the chin are thought by the women in one part of Africa 
 to be irresistible attractions.* In most, but not all parts of 
 the world, the men are more ornamented than the women, 
 and often in a different manner; sometimes, though rarely, 
 the women are hardly at all ornamented. As the women 
 are made by savages to perform the greatest share of the 
 work, and as they are not allowed to eat the best kinds of 
 food, so it accords with the characteristic selfishness of man 
 that they should not be allowed to obtain or use the finest 
 ornaments. Lastly, it is a remarkable fact, as proved by 
 the foregoing quotations, that the same fashions in modi- 
 fying the shape of the head, in ornamenting the hair, in 
 painting, tattooing, in perforating the nose, lips or ears, in 
 removing or filing the teeth, etc., now prevail, and have 
 long prevailed, in the most distant quarters of the world. 
 It is extremely improbable that these practices, followed by 
 BO many distinct nations, should be due to tradition from 
 any common source. They indicate the close similarity of 
 the mind of man, to whatever race he may belong, just as 
 do the almost universal habits of dancing, masquerading 
 and making rude pictures. 
 
 Having made these preliminary remarks on the admira- 
 tion felt by savages for various ornaments and for de- 
 formities most unsightly in our eyes, let us see how far the 
 men are attracted by the appearance of their women and 
 what are their ideas of beauty. I have heard it maintained 
 that savages are quite indifferent about the beauty of their 
 women, valuing them solely as slaves; it may, therefore, be 
 well to observe that this conclusion does not at all agree 
 with the care which the women take in ornamenting them- 
 selves, or with their vanity. Burchell f gives an amusing 
 account of a Bush-woman who used as much grease, red 
 ocher and shining powder ' ' as would have ruined any but 
 a very rich husband." She displayed also " much vanity 
 and too evident a consciousness of her superiority." Mr. 
 Winwood Reade informs me that the negroes of the West 
 Coast often discuss the beauty of their women. Some 
 competent observers have attributed the fearfully common 
 practice of infanticide partly to the desire felt by the 
 
 * Mantegazza, " Viaggi e Studi," p. 543. 
 \ "Travels in S. Africa," 1824, vol. i, p. 414.
 
 SECONDARY SEXUAL CHARACTERS. 659 
 
 women to retain their good looks.* In several regions the 
 women wear charms and use love-philters to gain the affec- 
 tions of the men; and Mr. Brown enumerates four plants 
 used for this purpose by the women of Northwestern 
 America, f 
 
 Beanie,]; an excellent observer, who lived many years 
 with the American Indians, says, in speaking of the women: 
 " Ask a Northern Indian what is beauty, and he will 
 answer, a broad fiat face, small eyes, high cheek-bones, 
 three or four broad black lines across each cheek, a low 
 forehead, a large broad chin, a clumsy hook nose, a tawny 
 hide and breasts hanging down to the belt." Pallas, who 
 visited the northern parts of the Chinese empire, says: 
 " Those women are preferred who have the Mandschu 
 form; that is to say, a broad face, high cheek-bones, very 
 broad noses, and enormous ears;" and Vogt remarks that 
 the obliquity of the eye, which is proper to the Chinese 
 and Japanese, is exaggerated in their pictures for the pur- 
 pose, as it " seems, of exhibiting its beauty, as contrasted 
 with the eye of the red-haired barbarians." It is well 
 known, as Hue repeatedly remarks, that the Chinese of the 
 interior think Europeans hideous, with their white 
 skins and prominent noses. The nose is far from being 
 too prominent, according to our ideas, in the natives of 
 Ceylon; yet "the Chinese in the seventh century, accus- 
 tomed to the fiat features of the Mongol races, were sur- 
 prised at the prominent noses of the Cingalese; and Thsang 
 described them as having * the beak of a bird, with the 
 body of a man/" 
 
 Finlayson, after minutely describing the people of 
 Cochin China, says that their rounded heads and faces are 
 their chief characteristics; and, he adds, "the roundness 
 of the whole countenance is more striking in the women, 
 
 *See for references, Gerland " Ueber das Aussterben der Natur- 
 vSlker," 1868, ss. 51, 53, 55; also Azara, "Voyages," etc., torn, ii, p. 
 116. 
 
 f On* the vegetable productions used by the Northwestern Ameri- 
 can Indians, " Pharmaceutical Journal," vol. x. 
 
 J " A Journey from Prince of Wales Fort," 8vo. edit., 1796, p. 89. 
 
 Quoted by Prichard, " Phys. Hist, of Mankind," 3d edit., vol. iv, 
 1844, p. 519; 'Vogt, " Lectures on Man," Eng. translat. p. 129. On 
 the opinion of the Chinese on the Cingalese, E. Tennent, "Ceylon," 
 1859, vol. ii, p. 107.
 
 660 TEE DESCENT OF MAN. 
 
 who are reckoned beautiful in proportion as they display 
 this form of face." The Siamese have small noses with 
 divergent nostrils, a wide mouth, rather thick lips, a 
 remarkably large face, with very high and broad cheek- 
 bones. It is, therefore, not wonderful that "beauty, 
 according to our notion, is a stranger to them. Yet they 
 consider their own females to be much more beautiful than 
 those of Europe." * 
 
 It is well known that with many Hottentot women the 
 posterior part of the body projects in a wonderful manner; 
 they are steatopygous; and Sir Andrew Smith is certain 
 that this peculiarity is greatly admired by the men. f He 
 once saw a woman who was considered a beauty, and she 
 was so immensely developed behind that when seated on 
 level ground she could not rise, and had to push herself 
 along until she came to a slope. Some of the women in 
 various negro tribes have the same peculiarity; and, accord- 
 ing to Burton, the Somal men " are said to choose their 
 wives by ranging them in a line and by picking her out 
 who projects farthest a tergo. Nothing can be more hate- 
 ful to a negro than the opposite form."J 
 
 With respect to color, the negroes railed Mungo Park 
 on the whiteness of his skin and the prominence of his 
 nose, both of which they considered as "unsightly and 
 unnatural conformations." He in return praised the glossy 
 jet of their skins and the lovely depression of their noses; 
 this they said was " honeymoutli," nevertheless they gave 
 him food. The African Moors, also, "knitted their brows 
 and seemed to shudder " at the whiteness of his skin. On 
 the eastern coast the negro boys Avhen they saw Burton, 
 cried out: " Look at the white man; does he not look like 
 a white ape?" On the western coast, as Mr. Winwood 
 Reade informs me, the negroes admire a very black skin 
 more than one of a lighter tint. But their horror of 
 
 *Prichard, as taken from Crawfurd and Finlayson, "Phys. Hist, 
 of Mankind," vol. iv, pp. 534, 535. 
 
 f Idem illustrissirnus viator dixit rnihi prsecinctorium vel tabulam 
 freminae, quod nobis teterriinum est, quondam permagno aestimari ab 
 hominibus in hac gente. Nunc res mutata est, et censent talem con- 
 formationem inininie optandam esse. 
 
 f'The Anthropological Review," Nov., 1864, p. 237. For addi- 
 tional reference, see Waitz, " Introduct. to Anthropology," Eng. 
 translat., 1863, vol. i, p. 105.
 
 SECONDARY SEXUAL CHARACTERS. 661 
 
 whiteness may be attributed, according to this same 
 traveler, partly to the belief held by most negroes that 
 demons and spirits are white, and partly to their thinking 
 it a sign of ill-health. 
 
 The Banyai of the more southern part of the continent 
 are negroes, but "a great many of them are of a light 
 coffee-and-milk color, and, indeed, this color is considered 
 handsome throughout the whole country;" so that here we 
 have a different standard of taste. "NYith the Kafirs, who 
 differ much from negroes, " the skin, except among the 
 tribes near Delagoa Bay, is not usually black, the prevail- 
 ing color being a mixture of black and red, the most 
 common shade being chocolate. Dark complexions as 
 being most common are naturally held in the highest 
 esteem. To be told that he is light colored or like a white 
 man would be deemed a very poor compliment by a Kafir. 
 I have heard of one unfortunate man who was^o very fair 
 that no girl would marry him." One of the titles of the 
 Zulu king is: "You who are black."* Mr. Galton, in 
 speaking to me about the natives of S. Africa, remarked 
 that their ideas of beauty seem very different from ours; 
 for in one tribe two slim, slight and pretty girls were not 
 admired by the natives. 
 
 Turning to other quarters of the world: in Java a yellow, 
 not a white girl, is considered, according to Madame 
 Pfeiffer, a beauty. A man of Cochin China " spoke with 
 contempt of the wife of the English ambassador, that she 
 had white teeth like a dog and a rosy color like that of 
 potato flowers." We have seen that the Chinese dislike 
 our white skin and that the North Americans admire " a 
 tawny hide." In South America the Yuracaras, who 
 inhabit the wooded, damp slopes of the eastern Cordillera, 
 are remarkably pale colored, as their name in their own 
 language expresses; nevertheless, they consider European 
 women as very inferior to their own.f 
 
 *Mungo Park's " Travels in Africa," 4to., 1816, pp. 53, 131. Bur- 
 ton's statement is quoted by Schaaffhausen, ' ' Archiv. f iir Anthro- 
 polog.," 1866, s. 163. On the Banyai, Livingstone, "Travels," p. 
 64. On the Kafirs, the Rev. J. Schooter, " The Kafirs of Natal and 
 the Zulu Country," 1857, p. 1. 
 
 fFor the Javans and Cochin-Chinese, see Waitz, " Introduct. to 
 Anthropology," Eng. translat., vol. i, p. 305. On the Yuracaras, A. 
 d'Orbigny, as quoted in Prichard, "Phys. Hist, of Mankind," vol. v, 
 3d edit., p. 476.
 
 662 THE DESCENT OF MAN, 
 
 In several of the tribes of North America the hair on the 
 head grows to a wonderful length; and Catlin gives a 
 curious proof how much this is esteemed, for the chief of 
 the Crows was elected to this office from having the longest 
 hair of any man in the tribe; namely, ten feet and seven 
 Inches. The Aymaras and Quichuas of South America 
 likewise have very long hair; and this, as Mr. D. Forbea 
 informs me, is so much valued as a beauty, that cutting it 
 off was the severest punishment which he could inflict on 
 them. In both the northern and southern halves of the 
 continent the natives sometimes increase the apparent 
 length of their hair by weaving into it fibrous substances. 
 Although the hair on the head is thus cherished, that on 
 the face is considered by the North American Indians " as 
 very vulgar/' and every hair is carefully eradicated. This 
 practice prevails throughout the American continent from 
 Vancouver'* Island in the north to Terra del Fuego in the 
 south. When York Minster, a Fuegian on board the 
 " Beagle," was taken back to his country, the natives told 
 him he ought to pull out the few short hairs on his face. 
 They also threatened a young missionary, who was left for 
 a time with them, to strip him naked and pluck the hairs 
 from his face and body, yet he was far from being a hairy 
 man. This fashion is carried so far that the Indians of 
 Paraguay eradicate their eyebrows and eyelashes, saying 
 that they do not wish to be like horses.* 
 
 It is remarkable that throughput the world the races 
 which are almost completely destitute of a beard dislike 
 hairs on the face and body, and take paina to eradicate 
 them. The Kalmucks are beardless and they are well 
 known, like the Americans, to pluck out all straggling 
 hairs ; and so it is with the Polynesians, some of the 
 Malays and the Siamese. Mr. Veitch states that the 
 Japanese ladies " all objected to our whiskers, considering 
 them very ugly, and told us to cut them off and be like 
 Japanese men." The New Zealanders have short, curled 
 beards; yet they formerly plucked out the hairs on the 
 face. They had a saying that " there is no woman for a 
 hairy man;" but it would appear that the fashion has 
 
 * " North American Indians," by G. Catlin, 3d edit. 1842, vol. i, p. 
 49; vol. ii. p. 227. On the nativesof Vancouver's Island, see Sproat, 
 " Scenes and Studies of Savage Life," 1868, p. 25. On the Indians 
 of Paraguay, Azara, "Voyages," torn, ii, p. 105.
 
 SECONDARY SEXUAL CHARACTERS. 663 
 
 changed in New Zealand, perhaps owing to the presence of 
 Europeans, and I am assured that beards are now admired 
 by the Maories."* 
 
 On the other hand, bearded races admire and greatly 
 value their beards; among the Anglo-Saxons every part of 
 the body had a recognized value; " the loss of the beard 
 being estimated at twenty shillings, while the breaking of 
 a thigh was fixed at only twelve, "f In the east men swear 
 solemnly by their beards. We have seen that Chinsurdi, 
 the chief of the Makalolo in Africa, thought that beards 
 were a great ornament. In the Pacific the Fijian's beard 
 is " profuse and bushy, and is his greatest pride;" while 
 the inhabitants of the adjacent archipelagoes of Tonga and 
 Samoa are beardless and abhor a rough chin." In one 
 island alone of the Ellice group "the men are heavily 
 bearded, and not a little proud thereof. " J 
 
 We thus see how widely the different races of man differ 
 in their taste for the beautiful. In every nation sufficiently 
 advanced to have made effigies of their gods or of their 
 deified rulers, the sculptors no doubt have endeavored to ex- 
 press their highest ideal of beauty and grandeur. Under 
 this point of view it is well to compare in our mind the 
 Jupiter or Apollo of the Greeks with the Egyptian or 
 Assyrian statues; and these with the hideous bas-reliefs 
 on the ruined buildings of Central America. 
 
 I have met with very few statements opposed to this 
 conclusion. Mr. Winwood Reade, however, who has had 
 ample opportunities for observation, not only with the 
 negroes of the west coast of Africa, but with those of the 
 interior who have never associated with Europeans, is con- 
 vinced that their ideas of beauty are, on the whole, the same 
 as ours; and Dr. Rohlfs writes to me to the same effect 
 
 * On the Siamese, Prickard, ibid, vol. iv, p. 533. On the Japanese, 
 Veitch in " Gardeners' Chronicle," 1860, p. 1104. On the New Zeal- 
 anders, Mantegazza, " Viaggi e Studi," 1867, p. 526. For the other 
 nations mentioned, see references in Lawrence, " Lectures on Physi- 
 ology," etc., 1822, p. 272. 
 ,fLubbeck, "Origin of Civilization," 1870, p. 321. 
 
 \ Dr . Barnard Davis quotes Mr. Prichard and others for these facts 
 in regard to the Polynesians, in "Anthropological Review," April, 
 1870, pp. 185, 191. 
 
 Ch. Comte has remarks to this effect in his"Traite de Legisla- 
 tion," 3d edit., 1887, p. 136.
 
 $64 THE DESCENT OF MAN. 
 
 with respect to Borneo and the countries inhabited by the 
 Pullo tribes* Mr. Keade found that he agreed with the 
 negroes in their estimation of the beauty of the native girls; 
 and that their appreciation of the beauty of European 
 women corresponded with ours. They admire long hair, 
 and use artificial means to make it appear abundant; they 
 admire also a beard, though themselves very scantily pro- 
 vided. Mi% Keade feels doubtful what kind of nose is most 
 appreciated; a girl has been heard to say: " I do not want 
 to marry him, he has got no nose;" and this shows that a 
 very fiat nose is not admired. We should, however, bear 
 in mind that the depressed, broad noses and projecting 
 jaws of the negroes of the west coast are exceptional types 
 with the inhabitants of Africa. Notwithstanding the fore- 
 going statements, Mr. Keade admits that negroes " do not 
 like the color of our skin; they look on blue eyes with aver- 
 sion, and they think our noses too long and our lips too 
 thin." He does not think it probable that negroes would 
 ever prefer the most beautiful European woman, on the 
 mere grounds of physical admiration, to a good-looking 
 negress.* 
 
 The general truth of the principle, long ago insisted on 
 by Humboldt,f that man admires and often tries to exag- 
 gerate whatever characters nature may have given him, is 
 shown in many ways. The practice of beardless races 
 extirpating every trace of a beard, and often all the hairs 
 on the body, affords one illustration. The skull has been 
 greatly modified during ancient and modern times by many 
 nations; and there can be little doubt that this has been 
 practiced, especially in North and South America, in order 
 
 *The "African Sketch-book," vol. ii, 1873, pp. 253, 394, 521. 
 The Fuegians, as I have been informed by a missionary who long 
 resided with them, consider European women as extremely beautiful ; 
 
 America, I cannot but think that this must be a mistake, unless 
 indeed the statement refers to the few Fuegians who have lived for 
 some time with Europeans, and who must consider us as superior 
 beings. I should add that a most experienced observer, Capt. Bur- 
 ton , believes that a woman whom we consider beautiful is admired 
 throughout the world. " Anthropological Review," March, 1864, p. 
 
 f" Personal Narrative," Eng. translat., vol. iv, p. 518, and else- 
 where. Mantegazza, in his " Viaggi e Studi," strongly insists on 
 this same principle.
 
 SECONDARY SEXUAL CHARACTERS. 665 
 
 to exaggerate some natural and admired peculiarity. Many 
 American Indians are known to admire a head so extremely 
 flattened as to appear to us idiotic. The natives on the 
 northwestern coast compress the head into a pointed cone; 
 and it is their constant practice to gather the hair into a 
 knot on the top of the head, for the sake, as Dr. Wilson 
 remarks, "of increasing the apparent elevation of the 
 favorite conoid form." The inhabitants of Arakhan 
 " admire a broad, smooth forehead, and, in order to pro- 
 duce it, they fasten a plate of lead on the heads of the 
 new-born children." On the other band, ''abroad, well- 
 rounded occiput is considered a great beauty" by the 
 natives of the Fiji Islands.* 
 
 As with the skuJ, so with the nose; the ancient Huiis, 
 during the age of Attila, were accustomed to flatten the 
 noses of their infants with bandages, "for the sake of 
 exaggerating a natural conformation." With the Tahitians, 
 to be called long-nose is considered as an insult, and they 
 compress the noses and foreheads of their children for the 
 sake of beauty. The same holds with the Malays of 
 Sumatra, the Hottentots, certain negroes and the natives 
 of Brazil, f The Chinese have by nature unusually small 
 feet; \ and it is well known that the women of the upper 
 classes distort their feet to make them still smaller. 
 Lastly, Humboldt thinks that the American Indians prefer 
 coloring their bodies with red paint in order to exaggerate 
 their natural tint; and until recently European women 
 added to their naturally bright colors by rouge and 
 white cosmetics ; but it may be doubted whether barbarous 
 nations have generally had any such intention in paint- 
 ing themselves. 
 
 * On the skulls of the American tribes, see Nott and Qliddon, 
 " Types of Mankind," 1854, p. 440; Prichard, " Phys. Hist, of Man- 
 kind," vol. i, 3d edit., p. 321 ; on the natives of Arakhan, ibid, vol. 
 iv, p. 537. Wilson, " Physical Ethnology," Smithsonian Institution, 
 1863, p. 288; on the Fijians, p. 290. Sir J. Lubbock ("Prehistoric 
 Times," 3d edit., 1869, p. 506) gives an excellent resume on this sub- 
 ject. 
 
 f On the Huns, Godron, " De 1'Espece," torn, ii, 1859, p. 300. On 
 the Tahitians, Waitz, " Anthropolog.," Eng. translat., vol. i, p. 305. 
 Marsden, quoted by Prichard, " Phys. Hist, of Mankind," 3d edit, 
 vol. v, p. 67. Lawrence, " Lectures on Physiology." p. 337. 
 
 IThis fact was ascertained in the " Reise der Novara : Anthropo- 
 log. Thiel," Dr. Weisbach, 18W, . 3S5.
 
 666 THE DESCENT OF MAN. 
 
 In the fashions of our own dress we see exactly the same 
 principle and the same desire to carry every point to an 
 extreme; we exhibit, also, the same spirit of emulation. 
 But the fashions of savages are far more permanent than 
 ours; and whenever their bodies are artificially modified, 
 this is necessarily the case. The Arab women of the Upper 
 Nile occupy about three days in dressing their hair; they 
 never imitate other tribes, " but simply vie with each other 
 in the superlativeness of their own style." Dr. Wilson, in 
 speaking of the compressed skulls of various American 
 races, adds, "such usages are among the least eradicable, 
 and long survive the shock of revolutions that change 
 dynasties and efface more important national peculiarities."* 
 The same principle comes into play in the art of breeding; 
 and we can thus understand, as I have elsewhere explained,! 
 the wonderful development of the many races of animals 
 and plants, which have been kept merely for ornament. 
 Fanciers always wish each character to be somewhat 
 increased; they do not admire a medium standard; they cer- 
 tainly do not desire any great and abrupt change in the 
 character of their breeds; they admire solely what they are 
 accustomed to, but they ardently desire to see each char- 
 acteristic feature a little more developed. 
 
 The senses of man and of the lower animaicj seem to be 
 so constituted that brilliant colors and certain forms, as 
 well as harmonious and rhythmical sounds, give pleasure 
 and are called beautiful; but why this should be so we 
 know not. It is certainly not true that there is in the 
 mind of man any universal standard of beauty with respect 
 to the human body. It is, however, possible that certain 
 tastes may in the course of time become inherited, 
 though there is no evidence in favor of this belief; and, if 
 so, each race would possess its own innate ideal standard of 
 beauty. It has been argued J that ugliness consists in an 
 approach to the structure of the lower animals, and no 
 doubt this is partly true with the more civilized nations, 
 in which intellect is highly appreciated; but this explana- 
 
 *" Smithsonian Institution," 1863, p. 289. On the fashions of 
 Arab women, Sir S. Baker, " The Nile Tributaries," 1867, p. 121. 
 
 \ "The Variation of Animals and Plants under Domestication," 
 vol. i, p. 214; vol. ii, p. 240. 
 
 J Schaaffhausen, " Archiv. fiir Anthropologie," 1866, s. 164.
 
 SECONDARY SEXUAL CHARACTERS. 667 
 
 tion will hardly apply to all forms of ugliness. The men 
 of each race prefer what they are accustomed to; they 
 carttiot endure any great change; but they like variety, and 
 admire each characteristic carried to a moderate extreme.* 
 Men accustomed to a nearly oval face, to straight and 
 regular features and to bright colors, admire, as we Euro- 
 peans know, these points when strongly developed. On 
 the other hand, men accustomed to a broad face, with high 
 cheek-bones, a depressed nose and a black skin admire 
 these peculiarities when strongly marked. No doubt 
 characters of all kinds may be too much developed for 
 beauty. Hence a perfect beauty, which implies many 
 characters modified in a particular manner, will be in every 
 race a prodigy. As the great anatomist Bichat long ago 
 said, if every one were cast in the same mold there would 
 be no such thing as beauty. If all our women were to 
 become as beautiful as the Venus de Medici we should 
 for a time be charmed, but we should soon wish for variety; 
 and, as soon as we had obtained variety, we should wish 
 to see certain characters a little exaggerated beyond the 
 then existing common standard. 
 
 *Mr. Bain has collected (" Mental and Moral Science," 1868, pp. 
 804-314) about a dozen more or less different theories of the idea of 
 beauty; but none are quite the same as that here given.
 
 66fc THE DESCENT OF MAN. 
 
 CHAPTER XX. 
 
 SECONDARY SEXUAL CHAEACTERS OP MAN Continued. 
 
 On the effects of the continued selection of women according to a 
 different standard of beauty in each race On the causes which 
 interfere with sexual selection in civilized and savage nations 
 Conditions favorable to sexual selection during primeval times 
 On the manner of action of sexual selection with mankind On 
 the women in savage tribes having some power to choose their 
 husbands Absence of hair on the body and development of the 
 beard Color of the skin Summary. 
 
 WE have seen in the last chapter that with all barbarous 
 races ornaments, dress and external appearance are highly 
 valued; and that the men judge of the beauty of their 
 women by widely different standards. We must next 
 inquire whether this preference and the consequent selec- 
 tion, during many generations, of those women which 
 appear to the men of each race the most attractive, has 
 altered the character either of the females alone, or of both 
 sexes. With mammals the general rule appears to be that 
 characters of all kinds are inherited equally by the males 
 and females; we might, therefore, expect that with man- 
 kind any characters gained by the females or by the males 
 through sexual selection would commonly be transferred to 
 the offspring of both sexes. If any change has thus been 
 effected it is almost certain that the different races would 
 be differently jiodined, as each has its own standard of 
 beauty. 
 
 With mankind, especially with savages, many causes 
 interfere with the action of sexual selection as far as the 
 bodily frame is concerned. Civilized men are largely 
 attracted by the mental charms of women, by their wealth, 
 and especially by their social position; for men rarely 
 marry into a much lower rank. The men who succeed in 
 obtaining the more beautiful women will not have a better 
 chance of leaving a long Une of descendants than othe.r
 
 SECONDARY SEXUAL CHAR AC! ER8. 669 
 
 men with plainer wives, save the few who bequeath their 
 fortunes according to primogeniture. With respect to the 
 opposite form of selection, namely, of the more attractive 
 men by the women, although in civilized nations women 
 have free or almost free choice, which is not the case with 
 barbarous races, yet their choice is largely influenced by 
 the social position and wealth of the men; and the success 
 of the latter in life depends much on their intellectual 
 powers and energy, or on the fruits of these same powers 
 in their forefathers. No excuse is needed for treating this 
 subject in some detail; for, as the German philosopher 
 Schopenhauer remarks, " the final aim of all love intrigues, 
 be they comic or tragic, is really of more importance than 
 all other ends in human life. What it all turns upon is 
 nothing less than the composition of the next genera- 
 tion. . . . It is not the weal or woe of any one indi- 
 vidual, but that of the human race to come, which is here 
 at stake. "* 
 
 There is, however, reason to believe that in certain civil- 
 ized and semi-civilized nations sexual selection has effected 
 something in modifying the bodily frame of some of the 
 members. Many persons are convinced, as it^appears to 
 me with justice, that our aristocracy, including under this 
 term all wealthy families in which primogeniture has long 
 prevailed, from having chosen during many generations 
 from all classes the more beautiful women as their wives, 
 have become handsomer, according to the European 
 standard, than the middle classes; yet the middle classes 
 are placed under equally favorable conditions of life for 
 the perfect development of the body. Cook remarks that 
 the superiority in personal appearance ' ' which is observa- 
 ble in the erees or nobles in all the other islands (of the 
 Pacific) is found in the Sandwich Islands " but this 
 may be chiefly due to their better food and manner of 
 life. 
 
 The old traveler Chardin, in describing the Persians, 
 says their " blood is now highly refined by frequent inter- 
 mixtures with the Georgians and Circassians, two nations 
 which surpass all the world in personal beauty. There is 
 hardly a man of rank in Persia who is not born of a 
 
 * " Schopenhauer and Darwinism," in "Journal of Anthropology. * 
 Jan., 1871, p. 333.
 
 670 TEE DESCENT OF MAN 
 
 Georgian or Circassian mother." He adds that they inherit 
 their beauty, " not from their ancestors, for without the 
 above mixture the men of rank in Persia, who are descend- 
 ants of the Tartars, would be extremely ugly."* Here is 
 a more curious case; the priestesses who attended the temple 
 of V^enus Erycina at San Giuliano, in Sicily, were selected 
 for their beauty out of the whole of Greece; they were not 
 vestal virgins, and Qua fcref ages, f who states the foregoing 
 fact, says that the women of San Giuliano are now famous 
 as the most beautiful in the island, and are sought by 
 artists as models. But it is obvious that the evidence in 
 all the above cases is doubtful. 
 
 The following case, though relating to savages, is well 
 worth giving from its curiosity. Mr. Winwood Reade in- 
 forms me that the Jollofs, a tribe of negroes on the west 
 coast of Africa, "are remarkable for their uniformly fine 
 appearance." A friend of his asked one of these men: 
 " How is it that every one whom I meet is so fine looking, 
 not only your men, but your women?" The Jollof an- 
 swered: "It is very easily explained; it has always been 
 our custom to pick out our worst-looking slaves and to 
 sell them." It need hardly be added that with all savages 
 female slaves serve as concubines. That this negro should 
 have attributed, whether rightly or wrongly, the fine 
 appearance of his tribe to the long-continued elimination 
 of the ugly women is not so surprising as it may at first 
 appear: for I have elsewhere shownj that negroes fully 
 appreciate the importance of selection in the breeding of 
 their domestic animals, and I could give from Mr. Eeade 
 additional evidence on this head. 
 
 The Causes Which Prevent or Check the Action of Sexual 
 Selection with Savages. The chief causes are, first so- 
 called communal marriages or promiscuous intercourse ; 
 secondly, the consequences of female infanticide; thirdly, 
 
 * These quotations are taken from Lawrence (" Lectures on Physi- 
 ology," etc., 1822, p. 393), who attributes the beauty of the upper 
 classes in England to the men having long selected the more beau- 
 tiful women. 
 
 f " Anthropologie," "Revue des Cours Scientifique," Oct., 1868, 
 p. 721. 
 
 J"The Variation of Animals and Plants under Domestication," 
 vol. i, p. 207.
 
 SECONDARY JEXUAL CHARACTERS. 671 
 
 early betrothals; and, lastly, the low estimation in which 
 women are held as mere slaves. These four points must 
 be considered rn some detail. 
 
 It is obvious that as long as the pairing of man or of 
 any other animal is left to mere chance, with no choice 
 exerted by either sex, there can be no sexual selection; and 
 no effect will be produced on the offspring by certain indi- 
 viduals having had an advantage over others in their court- 
 ship. Now, it is asserted that there exist at the present day 
 tribes which practice what Sir J. Lubbock by courtesy 
 calls communal marriages; that is, all the men and women 
 in the tribe are husbands and wives to one another. The 
 licentiousness of many savages is no doubt astonishing, but 
 it seems to me that more evidence is requisite, before we 
 fully admit that their intercourse is in any case promiscu- 
 ous. Nevertheless, all those who have most closely studied 
 the subject,* and whose judgment is worth much more 
 than mine, believe that communal marriage (this ex- 
 pression being variously guarded) was the original 
 and universal form throughout the world, including 
 therein the intermarriage of brothers and sisters. 
 The late Sir A. Smith, who had traveled widely 
 in S. Africa, and knew much about the habits of 
 savages there and elsewhere, expressed to me the strongest 
 opinion that no race exists in which woman is considered 
 as the property of the community. I believe that his judg- 
 ment was largely determined by what is implied by the 
 term marriage. Throughout the following discussion I 
 use the term in the same sense as when naturalists speak of 
 animals as monogamous, meaning thereby that the male is 
 accepted by or chooses a single female, and lives with her 
 
 *Sir J. Lubbock, " The Origin of Civilization," 1870, chap, iii, 
 especially pp. 60-67. Mr. M'Lennan, in his extremely valuable 
 work on " Primitive Marriage," 1865, p. 163, speaks of the union of 
 the sexes "in the earliest times as loose, transitory, and in some 
 degree promiscuous." Mr. M'Lennan and Sir J. Lubbock have col- 
 lected much evidence on the extreme licentiousness of savages at 
 the present time. Mr. L. H. Morgan, in his interesting memoir on 
 the classificatory system of relationship (" Proc. American Acad. of 
 Sciences," vol. vii, Feb., 1868, p. 475), concludes that polygamy 
 and all forms of marriage during primeval times were essentially 
 unknown. It appears, also, from" Sir J. Lubbock's work, that Bach- 
 ofen likewise believes that communal intercourse originally pre- 
 vailed.
 
 672 TEE DESCENT OF MAN. 
 
 either during the breeding -season or for the whole year, 
 keeping possession of her by the law of might; or, as when 
 they speak of a polygamous species, meaning- that the male 
 Jives with several females. This kind of marriage is all 
 that concerns us here, as it suffices for the w r ork of sexual 
 selection. But I know that some cf the writers above 
 referred to imply by the term marriage a recognized right 
 protected by the tribe. 
 
 The indirect evidence in favor of the belief of the former 
 prevalence of communal marriages is strong, and rests 
 chiefly on the terms of relationship which are employed 
 between the members of the same tribe, implying a con- 
 nection with the tribe, and not, with either parent. But 
 the subject is too large and complex for even an abstract to 
 be here given, and I will confine myself to a few remarks. It 
 is evident in the case of such marriages, or where the mar- 
 riage tie is very loose, that the relationship of the child to its 
 father cannot be known. But it seems almost incredible 
 that the relationship of the child to it* mother should ever 
 be completely ignored, especially as the women in most 
 savage tribes nurse their infants for a long time. Accord- 
 ingly, in many cases the lines of descent are traced through 
 the mother alone, to the exclusion of the father. But in 
 other cases the terms employed express a connection with 
 the tribe alone, to the exclusion even of the mother. It 
 seems possible that the connection between the related 
 members of the same barbarous tribe, exposed to all sorts 
 of danger, might be so much more important, owing to the 
 need of mutual protection and aid, than that between the 
 mother and her child, as to lead to the sole use of terms 
 expressive of the former relationships; but Mr. Morgan is 
 convinced that this view is by no means sufficient. 
 
 The terms of relationship used in different parts of the 
 world may be divided, according to the author just quoted, 
 into two great classes the classificatory and descriptive 
 the latter being employed by us. It is the classificatory 
 system which so strongly leads to the belief that communal 
 and other extremely loose forms of marriage were originally 
 universal. But, as far as I can see, there is no necessity on 
 this ground for believing in absolutely promiscuous inter- 
 course; and I am glad to find that this is Sir J. .Lubbock's 
 view. Men and women, like many of the lower animals, 
 might formerly have entered into strict though temporary
 
 SECONDARY SEXUAL CHARACTERS. 673 
 
 unions for each birth, and in this case nearly as much con- 
 fusion would have arisen in the terms of relationship as in 
 the case of promiscuous intercourse. As far as sexual 
 selection is concerned all that is required is that choice 
 should be exerted before the parents unite, and it signifies 
 little whether the unions last for life or only for a season. 
 
 Besides the evidence derived from the terms of relation- 
 ship, other lines of reasoning indicate the former wide prev- 
 alence of communal marriage. Sir J. Lubbock accounts 
 for the strange and widely extended habit of exogamy 
 that is, the men of one tribe taking Avives from a distinct 
 tribe by communism having been the original form of 
 intercourse; so that a man never obtained a wife for him- 
 self unless he captured her from a neighboring and hostile 
 tribe, and then she would naturally have become his sole 
 and valuable property. Thus the practice of capturing 
 wives might have arisen; and from the honor so gained it 
 might ultimately have become the universal habit. Ac- 
 cording to Sir J. Lubbock,* we can also thus understand 
 " the necessity of expiation for marriage as sei infringe- 
 ment of tribal rites, since, according to old ideas, a man 
 had no right to appropriate to himself that which belonged 
 to the whole tribe." Sir J. Lubbock further gives a 
 curious body of facts showing that in old times high honor 
 was bestowed on women who were utterly licentious; and 
 this, as he explains, is intelligible, if we admit that pro- 
 miscuous intercourse was the aboriginal, and therefore long 
 revered custom of the tribe, f 
 
 Although the manner of development of tlie marriage- 
 tie is an obscure subject, as we may infer from the diver- 
 gent opinions on several points between the three author/ 
 who have studied it most closely, namely, Mr. Morgan, 
 Mr. M'Lennan, and Sir J. Lubbock, yet from the fore- 
 going and several other lines of evidence it seems probable J 
 
 * " Address to British Association on the Social and Religious Con- 
 dition of the Lower Races of Man," 1870, p. 20. 
 
 f " Origin of Civilization," 1870, p. 86. In the several works above 
 quoted, there will be found copious evidence on relationship throug?,. 
 the females alone, or with the tribe alone. 
 
 JMr. C. Staniland Wake argues strongly (" Anthropologie,** 
 March, 1874, p. 197) against the views held by these three writerr. 
 on the former prevalence of almost promiscuous intercourse; and he 
 thinks that the classificatory system of relationship can be ctliej 
 wise explained.
 
 674 THE DESCENT OF MAN. 
 
 that the habit of marriage, in any strict sense of the word, 
 has been gradually developed; and that almost promiscu- 
 ous or very loose intercourse was once extremely common 
 throughout the world. Nevertheless, from the strength of 
 the feeling of jealousy all through the animal kingdom, as 
 well as from the analogy of the lower animals, more partic- 
 ularly of those which come nearest to man, I cannot 
 believe that absolutely promiscuous intercourse prevailed in 
 times past, shortly before man attained to his present rank 
 in the zoological scale. Man, as I have attempted to show 5 
 is certainly descended from some ape-like creature. With 
 the existing Quadrumaua, as far as their habits are known, 
 the males of some species are monogamous, but live during 
 only a part of the year with the females; of this the orang 
 seems to afford an instance. Several kinds, for example 
 some of the Indian and American monkeys, are strictly 
 monogamous, and associate all the year round with their 
 wives. Others are polygamous, for example the gorilla 
 and several American species, and each family lives sepa- 
 rate. Even when this occurs, the families inhabiting the 
 same district are probably somewhat social ; the chimpanzee, 
 for instance, is occasionally met with in large bands. 
 Again, other species are polygamous, but several males, 
 each with his own females, live associated in a body, as 
 with several species of baboons.* We may indeed conclude 
 from what we know of the jealousy of all male quadrupeds 
 armed, as many of them are, with special weapons for bat- 
 tling with their rivals, that promiscuous intercourse in a 
 state of nature is extremely improbable. The pairing may 
 not last for life, but only for each birth; yet if the males 
 which are the strongest and best able to defend or other- 
 wise assist their females and young, were to select the more 
 attractive females, this would suffice for sexual selection. 
 
 Therefore, looking far enough back in the stream of 
 time, and, judging from the social habits of man as he now 
 exists, the most probable view is that he aboriginally lived 
 in small communities, each with a single wife, or if power- 
 ful with several, whom he jealously guarded against all 
 
 *Brehm ("Illust. Thierleben," B. i, p. 77) says Cynocephalut 
 hamadryas lives in great troops containing twice as many adult 
 females as adult males. See Rengger on American polygamous 
 species, and Owen (" Anat. of' Vertebrates," vol. iii, p. 746) on Amer- 
 ican monogamous species. Other references might be added.
 
 SECONDARY SEXUAL CHARACTERS. 675 
 
 other men, Jr he may not have been a social animal, and 
 yet have lived with several wives, like the gorilla; for all 
 the natives "agree that but one adult male is seen in a 
 band; when the young male grows up a contest takes place 
 for mastery, and the strongest, by killing and driving out 
 the others, establishes himself as the head of the com- 
 munity."* The younger males, being thus .expelled and 
 wandering about, would, when at last successful in finding 
 a partner, prevent too close interbreeding within the limits 
 of the same family. 
 
 Although savages are now extremely licentious, and, 
 although communal marriages may formerly have largely 
 prevailed, yet many tribes practice some form of marriage, 
 but of a far more lax nature than that of civilized nations. 
 Polygamy, as just stated, is almost universally followed by 
 the leading men in every tribe. Nevertheless there are tribes, 
 standing almost at the bottom of the scale, Avhich are 
 strictly monogamous. This is the case with the Veddahs 
 of Ceylon; they have a saying, according to Sir J. Lub- 
 bock,f " that death alone can separate husband and wife." 
 An intelligent Kandyan chief, of course a polygamist, 
 " was perfectly scandalized at the utter barbarism of living 
 with only one wife, and never parting until separated by 
 death/ 7 " It was," he said, " just like the Wanderoo mon- 
 keys." Whether savages who now enter into some form of 
 marriage, either polygamous or monogamous, have re- 
 tained this habit from primeval times, or whether they 
 have returned to some form of marriage, after passing 
 through a stage of promiscuous intercourse, I will not 
 pretend to conjecture. 
 
 Infanticide. This practice is now very common through-? 
 out the world, and there is reason to believe that it pre> 
 vailed much more extensively during former times. J Bar- 
 barians find it difficult to support themselves and their 
 children, and it is a simple plan to kill their infants. In 
 South America some tribes, according to Azara, formerly 
 
 *Dr. Savage, in "Boston Journal of Nat. Hist.," vol. v, 1846-47, 
 p. 423. 
 
 f'PreWstorie Times," 1869, p. 424. 
 
 JMr. M'Lennan, "Primitive Marriage," 1865. See especially on 
 Kogamy and infanticide up. 130- 18J* "*65.
 
 676 THE DESCENT OF MAN. 
 
 destroyed so many infants of both sexes that they were on 
 the point of extinction. In the Polynesian Islands women 
 have been known to kill from four or five, to even ten of 
 their children; and Ellis could not find a single woman 
 who had not killed at least one. In a village on the 
 eastern frontier of India Col. McCullpch found not a 
 single female child. Wherever infanticide * prevails the 
 struggle for existence will be in so far less severe, and all 
 the members of the tribe will have an almost equally good 
 chance of rearing their few surviving children. In most 
 cases a larger number of female than of male infants are 
 destroyed, for it is obvious that the latter are of more value 
 to the tribe, as they will, when grown up, aid in defending 
 it, and can support themselves. But the trouble experienced 
 by the women in rearing children, their consequent loss 
 of beauty, the higher estimation set on them when few, 
 -and their happier fate, are assigned by the women them- 
 selves, and by various observers, as additional motives for 
 infanticide. 
 
 When, owing to female infanticide, the women of a tribe 
 were few, the habit of capturing wives from neighboring 
 tribes would naturally arise. Sir J. Lubbock, however, as 
 we have seen, attributes the practice in chief part to the 
 former existence of communal marriage, and to the men 
 having consequently captured women from other tribes to 
 hold as their sole property. Additional causes might be 
 assigned, such as the communities being very small, in 
 which case, marriageable women would often be deficient. 
 That the habit was most extensively practiced during 
 former times, even by the ancestors of civilized nations, is 
 clearly shown by the preservation of many curious customs 
 and ceremonies, of which Mr. McLennan has given an 
 interesting account. In our own marriages the "best 
 man " seems originally to have been the chief abettor of 
 the bridegroom in the act of capture. Now, as long as 
 men habitually procured their wives through violence and 
 
 *Pr. Gerland("Ueber das Aussterben der NaturvOlker," 1808) 
 has collected much information on infanticide, see especially ss. 27, 
 61, 54. Azara (" Voyages," etc., torn, ii, pp. 94, 116) enters in detail 
 on the motives. See also M'Lennan (ibid, p. 139) for cases in India. 
 In the former reprints of the 2d edition of this book an incorrect 
 quotation from Sir G. Grey was unfortunately given in the above 
 passage and has now been removed from the text.
 
 SECONDARY SEXUAL CHARACTERS. 677 
 
 craft, they would have been glad to seize on any woman, 
 and would not have selected the more attractive ones. But 
 as soon as the practice of procuring wives from a distinct 
 tribe was effected through barter, as now occurs in many 
 places, the more attractive women would generally have 
 been purchased. The incessant crossing, however, between 
 tribe and tribe, which necessarily follows from any form of 
 this habit, would tend to keep all the people inhabiting the 
 same country nearly uniform in character; and this would 
 interfere with the power of sexual selection in differentiat- 
 ing the tribes. 
 
 The scarcity of women, consequent on female infanti- 
 cide, leads, also, to another practice, that of polyandry, 
 still common in several parts of the world, and which 
 formerly, as Mr. McLennan believes, prevailed almost uni- 
 versally; but this latter conclusion is doubted by Mr. 
 Morgan and Sir J. Lubbock.* Whenever two or more men 
 are compelled to marry one women it is certain that all the 
 women of the tribe will get married, and there will be no 
 selection by the men of the more attractive women. But, 
 under these circumstances, the women no doubt will have 
 the power of choice, and will prefer the more attractive 
 men. Azara, f or instance, describes how carefully a Guana 
 woman bargains for all sorts of privileges before accepting 
 some one or more husbands; and the men in consequence 
 take unusual care of their personal appearance. So among 
 the Todas of India, who practice polyandry, the girls can 
 accept or refuse any man. f A very ugly man in these 
 cases would, perhaps, altogether fail in getting a wife, 
 or get one later in life; but the handsomer men, 
 although more successful in obtaining wives, would not, 
 as far as we can see, leave more offspring to inherit 
 their beauty than the less handsome husbands of the same 
 women. 
 
 Early Betrothals and Slavery of Women. With many 
 savages it is the custom to betroth the females while mere 
 infants ; and this would effectually prevent preference 
 
 * "Primitive Marriage," p. 208; Sir J. Lubbock, "Origin of Civili- 
 zation," p. 100. See also Mr. Morgan, loc. cit., on the former preva- 
 lence of polyandry. 
 
 f Azara, "Voyages," etc., torn, ii, pp. 92-95, Colonel Marshall 
 " Among the Todas," p. 212.
 
 678 THE DESCENT OF MAN. 
 
 being exerted on either side according to personal appear- 
 ance. But it would not prevent the more attractive women 
 from being afterward stolen or taken by force from their 
 husbands by the more powerful men; and this often hap- 
 pens in Australia, America and elsewhere. The same con- 
 sequences with reference to sexual selection would to a 
 certain extent follow, when women are valued almost 
 solely as slaves or beasts of burden, as is the case with 
 many savages. The men, however, at all times would 
 prefer the handsomest slaves, according to their standard of 
 beauty. 
 
 We thus see that several customs prevail with savages 
 which must greatly interfere with, or completely stop, the 
 action of sexual selection. On the other hand, the con- 
 ditions of life to which savages are exposed, and some of 
 their habits, are favorable to natural selection; and this 
 comes into play at the same time with sexual selection. 
 Savages are known to suffer severely from recurrent famines; 
 they do not increase their food by artificial means; they 
 rarely refrain from marriage,* and generally marry while 
 young. Consequently they must be subjected to occasional 
 hard struggles for existence, and the favored individuals 
 will alone survive. 
 
 At a very early period, before man attained to his present 
 rank in the scale, many of his conditions would be differ- 
 ent from what now obtains among savages. Judging from 
 the analogy of the lower animals, he would then either live 
 with a single female, or be a polygamist. The most pow- 
 erful and able males would succeed best in obtaining attrac- 
 tive females. They would also succeed best in the general 
 struggle for life, and in defending their females, as well as 
 their offspring, from enemies of all kinds. At this early 
 period the ancestors of man would not be sufficiently ad- 
 vanced in intellect to look forward to distant contingencies; 
 they would not foresee that the rearing of their children, 
 especially their female children, would make the struggle 
 for life severer for the tribe. They would be governed 
 more by their instincts and less by their reason than are 
 
 Burchell says ("Travels in S. Africa," vol. ii, 1824, p. 58), that 
 among the wild nations of Southern Africa, neither rnen nor women 
 ever pass their lives in a state of celibacy. Azara (" Voyages dans 
 1'Amerique Merid.," torn, ii, 1809, p. 21) makes precisely the same 
 remark in regard to the wild Indians of South America.
 
 . SECONDARY SEXUAL CHARACTERS. 679 
 
 savages at the present day. They would not at that 
 period have partially lost one of the strongest of all 
 instincts common to all lower animals, namely, tho love of 
 their young offspring; and consequently they would not 
 have practiced female infanticide. Women would not 
 have been thus rendered scarce, and polyandry wo-ild not 
 have been practiced; for hardly any other cause except the 
 scarcity of women seems sufficient to break down the nat- 
 ural and widely prevalent feeling of jealousy and the desire 
 of each male to possess a female for himself. Polyandry 
 would be a natural stepping-stone to communal marriages 
 or almost promiscuous intercourse; though the best authori- 
 ties believe that this latter habit preceded polyandry. 
 During primordial times there would be no early betroth- 
 als, for this implies foresight. Nor would women be 
 valued merely as useful slaves or beasts of burden. Both 
 sexes, if the females as well as the males were peronited to 
 exert any choice, would choose their partners not for 
 mental charms, or property, or social position, but almost 
 solely from external appearance. All the adults would 
 rnarry or pair, and all the offspring, as far as that was 
 possible, would be reared; so that the struggle for exist- 
 ence would be periodically excessively severe. Thus, luring 
 these times all the conditions for sexual selection would 
 have been more favorable than at a later period, when man 
 had advanced in his intellectual powers but had retro- 
 graded in his instincts. Therefore, whatever influence 
 sexual selection may have had in producing the differences 
 between the races of man and between man and the higher 
 Quadrumana, this influence would have been more power- 
 ful at a remote period than at the present day, though 
 probably not yet wholly lost. 
 
 The Manner of Action of Sexual Selection ivith Man- 
 kind. With primeval man under the favorable conditions 
 just stated, and with those savages who at the present time 
 enter into any marriage tie, sexual selection has probably 
 acted in the following manner, subject to greater 01 less 
 interference from female infanticide, early betrothals, etc. 
 The strongest and most vigorous men those who could 
 best defend and hunt for their families, who were pro- 
 vided with the best weapons and possessed the most prop- 
 erty, such as a large number of dogs or other animali-
 
 G80 THE DESCENT OF MAN. 
 
 would succeed in rearing a greater average number of off- 
 spring than the weaker and poorer members of the same 
 tribe. There can, also, be no doubt that such men would 
 generally be able to select the more attractive women. At 
 present the chiefs of nearly every tribe throughout the 
 world succeed in obtaining more than one wife. I hear 
 from Mr. Mantell that until recently almost every girl in 
 New Zealand who was pretty or promised to be pretty was 
 tapu to some chief. With the Kafirs, as Mr. C. Hamilton 
 states,* "the chiefs generally have the pick of the women 
 for many miles round and are most persevering in estab- 
 lishing or confirming their privilege." We have seen that 
 each race has its own style of beauty, and we know that it 
 is natural to man to admire each characteristic point in 
 his domestic animals, dress, ornaments and personal appear- 
 ance when carried a little beyond the average. If, then, 
 the several foregoing propositions be admitted, and I 
 cannot see that they are doubtful, it would be an inex- 
 plicable circumstance if the selection of the more attractive 
 women by the more powerful men of each tribe who would 
 rear on an average a greater number of children did not 
 after the lapse of many generations somewhat modify the 
 character of the tribe. 
 
 When a foreign breed of our domestic animals is intro- 
 duced into a new country, or when a native breed is long 
 and carefully attended to, either for use or ornament, it is 
 found after several generations to have undergone a greater 
 or less amount of change whenever the means of compari- 
 son exist. This follows from unconscious selection during 
 a long series of generations that is, the preservation of the 
 most approved individuals without any wish or expecta- 
 tion of such a result on the part of the breeder. So again, 
 if during many years two careful breeders rear animals of 
 the same family, and do not compare them together or 
 with a common standard, the animals are found to have 
 become, to the surprise of their owners, slightly different, f 
 Each breeder has impressed, as Von Nathusius well ex- 
 presses it, the character of his own mind his own taste 
 and judgment on his animals. What reason, then, can 
 
 * "Anthropological Review," Jan., 1870, p. xvi. 
 f " The Variation of Animals and Plants under Domestication," vol 
 ii, pp. 210-217.
 
 SECONDARY SEXUAL CHARACTERS. 681 
 
 be assigned why similar results should not follow from the 
 long-coutinued selection of the most admired women by 
 those men of each tribe who were able to rear the greatest 
 number of children? This would be unconscious selection, 
 for an effect would be produced, independently of any wish 
 or expectation on the part of the men who preferred cer- 
 tain women to others. 
 
 Let us suppose the members of a tribe, practicing som& 
 form of marriage, to spread over an unoccupied continent, 
 they would soon split up into distinct hordes, separated 
 from each other by various barriers, and still more effectu- 
 ally by the incessant wars between all barbarous nations. 
 The hordes would thus be exposed to slightly different 
 conditions and habits of life and would sooner or later come 
 to differ in some small degree. As soon as this occurred, 
 each isolated tribe would form for itself a slightly different 
 standard of beauty;* and then unconscious selection would 
 come into action through the more powerful and leading 
 men preferring certain women to others. Thus the dif- 
 ferences between the tribes, -at first very slight, would 
 gradually and inevitably be more or less increased. 
 
 With animals in a state of nature, many characters 
 proper to the males, such as size, strength, special weapons, 
 courage and pugnacity, have been acquired through the 
 law of battle. The semi-human progenitors of man, like 
 their allies the Quadrumana, will almost certainly have 
 been thus modified; and, as savages still fight for the pos- 
 session of their women, a similar process of selection has 
 probably gone on in a greater or less degree to the present 
 day. Other characters proper to the males of the lower 
 animals, such as bright colors and various ornaments, have 
 been acquired by the more attractive males having been 
 preferred by the females. There are, however, exceptional 
 cases in which the males are the selectors, instead of having 
 been the selected. We recognize such cases by the females 
 being more highly ornamented than the males their orna- 
 mentat characters having been transmitted exclusively or 
 
 * An ingenious writer argues, from a comparison of the pictures of 
 Raphael, Rubens, and modern French artists, that the idea of beauty 
 is not absolutely the same even throughout Europe; see the " Lives 
 of Haydn and Mozart," by Bombet (otherwise M. Beyle), English 
 translat. , p. 278.
 
 682 THE DESCENT OF MAN. 
 
 chiefly to their female offspring. One such case has been 
 described in the order to which man belongs, that of the 
 Rhesus monkey. 
 
 Man is more powerful in body and mind than woman, 
 and in the savage state he keeps her in a far more abject 
 state of bondage than does the male of any other animal; 
 therefore it is not surprising that he should have gained 
 the power of selection. Women are everywhere conscious 
 of the value of their own beauty; and when they have the 
 means, they take more delight in decorating themselves 
 with all sorts of ornaments than do men. They borrow 
 the plumes of male birds, with which nature has decked 
 this sex in order to charm the females. As women have 
 long been selected for beauty, it is not surprising that some 
 of their successive variations should have been transmitted 
 exclusively to the same sex; consequently that they should 
 have transmitted beauty in a somewhat higher degree to 
 their female than to their male offspring, and thus have 
 become more beautiful, according to general opinion, than 
 men. Women, however, certainly transmit most of their 
 characters, including some beauty, to their offspring of both 
 sexes; so that the continued preference by the men of each 
 race for the more attractive women, according to their 
 standard of taste, will have tended to modify in the same 
 manner all the individuals of both sexes belonging to the 
 race. 
 
 With respect to the other form of sexual selection (which 
 with the lower animals is much the more common), namely, 
 when the females are the selectors, and accept only those 
 males which excite or charm them most, we have reason to 
 believe that it formerly acted on our progenitors. Man in 
 all probability owes his beard, and perhaps some other char- 
 acters, to inheritance from an ancient progenitor who thus 
 gained his ornaments. But this form of selection may 
 have occasionally acted during later times; for in utterly 
 barbarous tribes the women have more power in choosing, 
 rejecting and tempting their lovers, or of afterward chang- 
 ing their husbands than might have been expected. As 
 this is a point of some importance, I will give in detail 
 Buch evidence as I have been able to collect. 
 
 Hearne describes how a woman in one of the tribes of 
 Arctic America repeatedly ran away from her husband and 
 joined her lover; and with the Charruas of South America,
 
 SECONDARY SEXUAL CHARACTERS. 683 
 
 according to Azara, divorce is quite optional. Among the 
 Abipones, a man on choosing a wife bargains with the parents 
 about the price. But ' ' it frequently happens that the girl 
 rescinds what has been agreed upon between the parents 
 and the bridegroom, obstinately rejecting the very men- 
 tion of marriage." She often runs away, hides herself and 
 thus eludes the bridegroom. Capt. Musters, who lived with 
 the Patagpnians, says that their marriages are always 
 settled by inclination; "if the parents make a match con- 
 trary to the daughter's will, she refuses and is never com- 
 pelled to comply." In Tierra del Fuego a young man first 
 obtains the consent of the parents by doing them some 
 service, and then he attempts carry off the girl; "but if she 
 is unwilling, she hides herself in the woods until her admirer 
 is heartily tired of looking for her and gives up the pur- 
 suit; but this seldom happens." In the Fiji Islands the 
 man seizes on the woman whom he wishes for his wife by 
 actual or pretended force; but " on reaching the home of 
 her abductor, should she not approve of the match, she 
 runs to some one who can protect her; if, however, she is 
 satisfied, the matter is settled forthwith." With the Kal- 
 mucks there is a regular race between the bride and bride- 
 groom, the former having a fair start; and Clarke " was 
 assured that no instance occurs of a girl being caught, 
 unless she has a partiality to the pursuer." Among the 
 wild tribes of the Malay Archipelago there is also a racing 
 match; and it appears from M. Bourien's account, as Sir 
 J. Lubbock remarks, that "the race 'is not to the swift, 
 nor the battle to the strong/ but to the young man who 
 has the good fortune to please his intended bride." A sim- 
 ilar custom, with the same result, prevails with the Korarks 
 of Northeastern Asia. 
 
 Turning to Africa the Kafirs buy their wives, and girls 
 are severely beaten by their fathers if they will not accept 
 a chosen husband ; but it is manifest from many facts given 
 by the Kev. Mr. Shooter, that they have considerable 
 power of choice. Thus, very ugly, though rich men, have 
 been known to fail in getting wives. The girls, before con- 
 senting to be betrothed, compel the men to show them- 
 selves off first in front and then behind, and "exhibit their 
 paces." They have been known to propose to a man, and 
 they not rarely run away with a favored lover. So, again, 
 Mr. Leslie, who was intimately acquainted with the Kafirs,
 
 684 THE DESCENT OF MAN. 
 
 says: " It is a mistake to imagine that a girl is sold by her 
 father in the same manner, and with the same authority, 
 with which he would dispose of a cow." Among the 
 degraded Bushmen of S. Africa, " when a girl has grown 
 up to womanhood without having been betrothed, which, 
 however, does not often happen, her lover must gain her 
 approbation as well as that of the parents."* Mr. Winwood 
 Reade made inquiries for me with respect to the negroes of 
 Western Africa, and he informs me that "the women, at 
 least among the more intelligent Pagan tribes, have no dif- 
 ficulty in getting the husbands whom they may desire, 
 although it is considered unwomanly to ask a man to marry 
 them. They are quite capable of falling in love and of 
 forming tender, passionate and faithful attachments." 
 Additional cases could be given. 
 
 We thus see that with savages the women are not in 
 quite so abject a state in relation to marriage as has often 
 been supposed. They can tempt the men whom they 
 prefer, and can sometimes reject those whom they dislike, 
 either before or after marriage. Preference on the part of 
 women, steadily acting in any one direction, would ulti- 
 mately affect the character of the tribe; for the women 
 would generally choose not merely the handsomest men, 
 according to their standard of taste, but those who were at 
 the same time best able to defend and support them. Such 
 well-endowed pairs would commonly rear a larger number 
 of offspring than the less favored. The same result would 
 obviously follow in a still more marked manner if there 
 was selection on both sides; that is, if the more attractive, 
 and, at the same time, more powerful, men were to prefer, 
 and were preferred by, the more attractive women. And 
 this double form of selection seems actually to have 
 
 *Azara "Voyages," etc., torn, ii, p. 23. Dobrizhoffer, "An Ac- 
 count of the Abipones," vol. ii, 1822, p. 207. Capt. Musters, in 
 " Proc. R. Geograph. Soc.," vol. xv, p. 47 Williams on the Fiji 
 Islanders, as quoted by Lubbock, "Origin of Civilization," 1870. p. 
 79. On the Fuegians, King and Fitzroy, " Voyages of the 'Advent- 
 ure' and ' Beagle,' " vol. ii, 1839, p. 182. On the Kalmucks, quoted by 
 M'Lennan, " Primitive Marriage," 1865, p. 32. On the Malays, Lub- 
 bock, ibid, p. 76. The Rev. J. Shooter, "On the Kafirs of Natal," 
 1857, pp. 52-60. Mr. D. Leslie, "Kafir Character and Customs," 
 1871, p. 4. On the Bushmen, Bnrchell, " Travels in S. Africa," vol. 
 ii, 1824, p. 59. On the Koraks by McKennan, as quoted by Mr. 
 Wake, in " Anthropologia," Oct., 1873, p. 75.
 
 SECONDARY SEXUAL CHARACTERS. 685 
 
 occurred, especially during the earlier periods of our long 
 history. 
 
 We will now examine a little more closely some of the 
 characters which distinguish the several races of man from 
 one another and from the lower animals, namely, the 
 greater or less deficiency of hair on the body and the color 
 of the skin. We need say nothing about the great diversity 
 in the shape of the features and of the skull between the 
 different races, as we have seen in the last chapter how dif- 
 ferent is the standard of beauty in these respects. These 
 characters will, therefore, probably have been acted on 
 through sexual selection; but we have no means of judging 
 whether they have been acted on chiefly from the male or 
 female side. The musical faculties of man have likewise 
 been already discussed. 
 
 Absence of Hair on the Body and Its Development on 
 the Face and Head. Prom the presence of the woolly hair 
 or lanugo on the human fetus, and of rudimentary hairs 
 scattered over the body during maturity, we may infer that 
 man is descended from some animal which was born hairy 
 and remained so during life. The loss of hair is an incon- 
 venience and probably an injury to man, even in a hot 
 climate, for he is thus exposed to the scorching of the sun, 
 and to sudden chills, especially during Avet weather. As 
 Mr. Wallace remarks, the natives in all countries are glad 
 to protect their naked backs and shoulders with some 
 slight covering. No one supposes that the nakedness of 
 the skin is any direct advantage to man; his body, there- 
 fore, cannot have been divested of hair through natural 
 selection.* Nor, as shown in a former chapter, havs we 
 any evidence that this can be due to the direct actiot) of 
 climate, or that it is the result of correlated development. 
 
 The absence of hair on the body is to a certain extent 8 
 
 *" Contributions to the Theory of Natural Selection," 1870, p. 
 346. Mr. Wallace believes (p. 350) "that some intelligent power 
 has guided or determined the development of man ;" and he con- 
 siders the hairless condition of the skin as coming under this 
 head. The Rev. T. R. Stebbing, in commenting on this view 
 ("Transactions of Devonshire Assoc. for Science, 1870) remarks, 
 that had Mr. Wallace " employed his usual ingenuity on the ques- 
 tion of man's hairless skin he might have seen the possibility of it? 
 selection through its superior beauty or the health att^cuing t< 
 superior cleanliness."
 
 686 THE DESCENT OF MAN. 
 
 Becondary sexual character; for in all parts of the world 
 women are less hairy than the men. Therefore we may 
 reasonably suspect that this character has been gained 
 through sexual selection. We know that the faces of 
 several species of monkeys, and large surfaces at the 
 posterior end of the body of other species, have been 
 denuded of hair; and this we may safely attribute to 
 sexual selection, for these surfaces are not only vividly 
 colored, but sometimes, as with the male mandrill and 
 female rhesus, much more vividly in the one sex than in 
 the other, especially during the breeding-season. I am 
 informed by Mr. Bartlett that, as these animals gradually 
 reach maturity, the naked surfaces grow larger compared 
 with the size of their bodies. The hair, however, appears 
 to have been removed, not for the sake of nudity, but that 
 the color of the skin may be more fully displayed. So, 
 again, with many birds, it appears as if the head and neck 
 had been divested of feathers, through sexual selection, to 
 exhibit the brightly colored skin. 
 
 A.S the body in woman is less hairy than in man, and as 
 this character is common to all races, we may conclude 
 that it was our female semi-human ancestors who were first 
 divested of ha ; r, and that this occurred at an extremely re- 
 mote period before the several races had diverged from a 
 common stock. While our female ancestors were gradually 
 acquiring this new character of nudity they must have 
 transmitted it almost equally to their offspring of both 
 sexes while young; so that its transmission, as with the 
 ornaments of many mammals and birds, has not been 
 limited either by sex or age. There is nothing surprising 
 in a partial loss of hair having been esteemed as an orna- 
 ment by our ape-like progenitors, for we have seen that in- 
 numerable strange characters have been thus esteemed by 
 animals of all kinds and have consequently been gained 
 through sexual selection. Nor is it surprising that a 
 slightly injurious character should have been thus acquired; 
 for we know that this is the case with the plumes of certain 
 birds, and with the horns of certain stags. 
 
 The females of some of the anthropoid apes, as stated in 
 a former chapter, are somewhat less hairy on the under 
 surface than the males; and here we have what might have 
 afforded a commencement for the process of denudation. 
 With respect to the completion of the process through
 
 SECONDARY SEXUAL CHARACTERS. 687 
 
 sexual selection, it is well to bear in mind the New Zea- 
 land proverb: " There is no woman for a hairy man." All 
 who have seen photographs of the Siamese hairy family 
 will admit how ludicrously hideous is the opposite extreme 
 of excessive hairiness. And the king of Siam had to bribe 
 a man to marry the first hairy woman in the family; and 
 she transmitted this character to her young offspring of 
 both sexes.* 
 
 Some races are much more hairy than others, especially 
 the males; but it must not be assumed that the more hairy 
 races, such as the Europeans, have retained their primor- 
 dial condition more completely than the naked races, such 
 as the Kalmucks or Americans. It is more probable that 
 the hairiness of the former is due to partial reversion; for 
 characters which have been at some former period long in- 
 herited are always apt to return. We have seen that idiots 
 are often very hairy, and they are apt to revert in other 
 characters to a lower animal type. It does not appear that 
 a cold climate has been influential in leading to this kind 
 of reversion; excepting perhaps with the negroes, who have 
 been reared during several generations in the United 
 States,f and possibly with the Ainos, who inhabit the 
 northern islands of the Japan archipelago. But the laws 
 of inheritance are so complex that we can seldom under- 
 stand their action. If the greater hairiness of certain 
 races be the result of reversion, unchecked by any form of 
 selection, its extreme variability, even within the limits of 
 the same race, ceases to be remarkable. J 
 
 * " The Variation of Animals and Plants under Domestication," 
 vol. ii, 1868, p. 327. 
 
 f " Investigations into Military and Anthropological Statistics of 
 American Soldiers," by B. A. Gould, 1869; p. 568: Observations 
 were carefully made on the hairiness of 2,129 black and colored 
 soldiers, while they were bathing; and by looking to the published 
 table, " it is manifest at a glance that there is but little, if any, dif- 
 ference between the white and the black races in this respect." It is, 
 however, certain that negroes in their native and much hotter land 
 of Africa, have remarkably smooth bodies. It should be particularly 
 -observe*~d, that both pure blacks and mulattoes were included in 
 the above enumeration; and this is an unfortunate circumstance, as 
 in accordance with a principle, the truth of which I have elsewhere 
 proved, crossed races of man would be eminently liable to revert to 
 the primordial hairy character of their early ape-like progenitors. 
 
 \ Hardly any view advanced in this work has met with so much 
 disfavor (see for instance, Spengel, "Die Fortschritte des Darwin-
 
 688 THE DESCENT OF MAN. 
 
 With respect to the beard in man, if we turn to our best 
 guide, the Qaadrumana, we find beards equally developed 
 in both sexes of many species, but in some, either confined 
 to the males, or more developed in them than in the females. 
 From this fact and from the curious arrangement, as well 
 as the bright colors of the hair about the heads of many 
 monkeys, it is highly probable, as before explained, that 
 the males first acquired their beards through sexual selec- 
 tion as an ornament, transmitting them in most cases, 
 equally or nearly so, to their offspring of both sexes. AVe 
 know from Eschricht* that with mankind the female as 
 well as the male fetus is furnished with much hair on the 
 face, especially round the mouth; and this indicates that 
 we are descended from progenitors of whom both sexes 
 were bearded. It appears, therefore, at first sight probable 
 that man has retained his beard from a very early period, 
 while woman lost her beard at the same time that her body 
 became almost completely divested of hair. Even the color 
 of our beards seems to have been inherited from an ape- 
 like progenitor; for when there is any difference in tint 
 between the hair of the head and the beard, the latter is 
 lighter colored in all monkeys and in man. In those 
 Quadrumana in which the male has a larger beard than 
 that of the female, it is fully developed only at maturity, 
 just as with mankind; and it is possible that only the latei 
 stages of development have been retained by man. In op- 
 position to this view of the retention of the beard from an 
 early period is the fact of its great variability in different, 
 races, and even within the same race; for this indicates 
 reversion long lost characters being very apt to vary on 
 reappearance. 
 
 Nor must we overlook the part which sexual selection 
 may have played in later times; for we know that with 
 savages the men of the beardless races take infinite pain* 
 in eradicating every hair from their faces as something 
 odious, while the men of the bearded races feel the greatest 
 
 ismus," 1874, p. 80) as the above explanation of the loss of hair in 
 mankind through sexual selection; but none of the opposed argu- 
 ments seem to me of much weight, in comparison with the facts 
 showing that the nudity of the skin is to a certain extent a secon- 
 dary sexual character in man and in some of the Quadrumana. 
 
 * " Ueber die Richtung der Haare am Menschlichen Korper," in 
 Mailer's " Archiv f ur Anat. und Phys.," 1837, s. 40.
 
 SECONDARY SEXUAL CHARACTERS. 689 
 
 pride in their beards. The women, no doubt, participate 
 in these feelings, and if so sexual selection can hardly have 
 failed to have effected something in the course of later 
 times. It is also possible that the long-continued habit of 
 eradicating the hair may have produced an inherited effect. 
 Dr. Brown-Sequard has shown that if certain animals are 
 operated on in a particular manner their offspring are 
 affected. Further evidence could be given of the inherit- 
 ance of the effects of mutilations; but a fact lately ascer- 
 by Mr. Salvin * has a more direct bearing on the present 
 question; for he has shown that the motmots, which are 
 known habitually to bite off the barbs of the two central 
 tail-feathers, have the barbs of these feathers naturally 
 somewhat reduced. f Nevertheless, with mankind the 
 habit of eradicating the beard and the hairs on the body 
 would probably not have arisen until these had already 
 become by some means reduced. 
 
 It is difficult to form any judgment as to how the hair 
 on the head became developed to its present great length 
 in many races. EschrichtJ states that in the human fetus 
 the hair on the face during the fifth month is longer than 
 that on the head; and this indicates that our semi-human 
 progenitors were not furnished with long tresses, which 
 must, therefore, have been a late acquisition. This is like- 
 wise indicated by the extraordinary difference in the length 
 of the hair in the different races; in the negro the hair 
 forms a mere curly mat; with us it is of great length, and 
 with the American natives it not rarely reaches to the 
 ground. Some species of Semnopithecus' have their heads 
 covered with moderately long hair, and this probably serves 
 as an ornament and was acquired through sexual selection. 
 The same view may, perhaps, be extended to mankind, for 
 we know that long tresses are now and were formerly much 
 admired, as may be observed in the works of almost every 
 poet. St. Paul says: "If a woman have long hair it is a 
 
 * On the tail-feathers of Momotus, " Proc. Zoolog. Soc.," 1873, p. 
 429 - 
 
 (Mr. Sproat has suggested (" Scenes and Studies of Savage Life," 
 1868, p. 25) this same view. Some distinguished ethnologists, among 
 others M. Gosse of Geneva, believe that artificial modifications of th 
 skull tend to be inherited. 
 
 J " Uber die Richtung," ibid, s. <0.
 
 690 THE DESCENT OF MAN. 
 
 glory to her;" and we have seen that in North America a 
 chief was elected solely from the length of his hair. 
 
 Color of the Skin. The best kind of evidence that in 
 man the color of the skin has been modified through sexual 
 selection is scanty; for in most races the sexes do not diifer 
 in this respect, and only slightly, as we have seen, io 
 others. We know, however, from the many facts already 
 given that the color of the skin is regarded by the men of 
 all races as a highly important element in their beauty; so 
 that it is a character which would be likely to have been 
 modified through selection, as has occurred in innumerable 
 instances with the lower animals. It seems at first sight a 
 monstrous supposition that the jet blackness of the negro 
 should have been gained through sexual selection; but 
 this view is supported by various analogies, and we know 
 that negroes admire their own color. With mammals 
 when the sexes differ in color the male is often black or 
 much darker than the female; and it depends merely on 
 the form of inheritance whether this or any other tint is 
 transmitted to both sexes or to one alone. The resemblance 
 to a negro in miniature of Pithecia satanas with his 
 jet-black skin, white rolling eyeballs and hair parted on 
 the top of the head is almost ludicrous. 
 
 The color of the face differs much more widely in the 
 various kinds of monkeys than it does in the races of man; 
 and we have some reason to believe that the red, blue, 
 orange, almost white and black tints of their skin, even 
 when common to both sexes, as well as the bright colors of 
 their fur and the ornamental tufts about the head, have 
 all been acquired through sexual selection. As the order 
 of development during growth generally indicates the order 
 in which the characters of a species have been developed 
 and modified during previous generations, and as the 
 newly born infants of the various races of man do not differ 
 nearly as much in color as do the adults, although their 
 bodies are as completely destitute of hair, we have some 
 slight evidence that the tints of the different races were 
 acquired at a period subsequent to the removal of the hair, 
 which must have occurred at a very early period in the 
 history of man. 
 
 Summary. We may . conclude .that the greater size,
 
 SECONDARY SEXUAL CHARACTERS. 691 
 
 strength, courage^ pugnacity, and energy of man, in com- 
 parison with women, were acquired during primeval times, 
 and have subsequently been augmented, chiefly through 
 the contests of rival males for the possession of the females. 
 The greater intellectual vigor and power of invention in 
 man is probably due to natural selection, combined with 
 the inherited effects of habit, for the most able men will 
 have succeeded best in defending and providing for them- 
 selves and for their wives and offspring. As far as the ex- 
 treme intricacy of the subject permits us to judge, it 
 appears that our male ape-like progenitors acquired their 
 beards as an ornament to charm or excite the opposite sex, 
 and transmitted them only to their male offspring. The 
 females apparently first had their bodies denuded of hair, 
 also as a sexual ornament; but they transmitted this char- 
 acter almost equally to both sexes. It is not improbable 
 that the females were modified in other respects for the 
 same purpose and by the same means; so that women have 
 acquired sweeter voices and become more beautiful than 
 men. 
 
 It deserves attention that with mankind the conditions 
 were in many respects much more favorable for sexual 
 selection, during a very early period, when man had only 
 just attained to the rank of manhood, than during later 
 times. For he would then, as we may safely conclude, 
 have been guided more by his instinctive passions, and 
 less by foresight or reason. He would have jealousy 
 guarded his wife or wives. He would not have practiced 
 infanticide; nor valued his wives merely as useful slaves; 
 nor have been betrothed to them during infancy. Hence 
 we may infer that the races of men were differentiated, as 
 far as sexual selection is concerned, in chief part at a very 
 remote epoch ; and this conclusion throws light on the 
 remarkable fact that at the most ancient period, of which 
 we have as yet any record, the races of man had already 
 come to differ nearly or quite as much as they do at the 
 present day. 
 
 "The views here advanced, on the part which sexual selec- 
 tion has played in the history of man, want scientific pre- 
 cision. He who does not admit this agency in the case of 
 the lower animals, will disregard all that I have written in 
 the later chapters on man. We cannot positively say that 
 this character, but not that, has been thus modified; it has,
 
 692 THE DESCENT OF MAN. 
 
 however, been shown that the races of man differ from 
 each other and from their nearest allies, in certain charac- 
 ters which are of no service to them in their daily habits 
 of life, and which it is extremely probable would have 
 been modified through sexual selection. \Ve have seen that 
 with the lowest savages the people of each tribe admire their 
 own characteristic qualities the shape of the head and 
 face, the squareness of the cheek-bones, the prominence or 
 depression of the nose, the color of the skin, the length of 
 the hair on the head, the absence of hair on the face and 
 body, or the presence of a great beard, and so forth. Hence 
 these and other such points could hardly fail to be slowly 
 and gradually exaggerated from the more powerful and able 
 men in each tribe, who would succeed in rearing the largest 
 number of offspring, having selected during many genera- 
 tions for their wives the most strongly characterized and 
 therefore most attractive women. For my own part I con- 
 clude that of all the causes which have led to the differ- 
 ences in external appearance between the races of man, and 
 to a certain extent between man and the lower animals, 
 sexual selection has been the most efficient.
 
 GENERAL SUMMARY AND CONCLUSION. 693 
 
 CHAPTER XXI. 
 
 GENERAL SUMMARY AND CONCLUSION. 
 
 Main conclusion that man is descended from some lower form 
 Manner of development Genealogy of man Intellectual and 
 moral faculties Sexual selection Concluding remarks. 
 
 A BRIEF summary will be sufficient to recall to the 
 reader's mind the more salient points in this work. Many 
 of the views which have been advanced are highly specula- 
 tive, and some no doubt will'prove erroneous; but I have 
 in every case given the reasons which have led me to one 
 view rather than to another. It seemed worth while to try 
 how far the principle of evolution would throw light on 
 some of the more complex problems in the natural history 
 of man. False facts are highly injurious to the progress 
 of science, for they often endure long; but false views, if 
 supported by some evidence, do little harm, for every one 
 takes a salutary pleasure in proving their falseness; and, 
 when this is done, one path toward error is closed and the 
 road to truth is often at the same time opened. 
 
 The main conclusion here arrived_at T and now heldjby 
 many_ natural iste, wh"o are well"competent_to form a spuno" 
 ' ids 
 
 iudgmeTrt, IB that man is descended fvnnTsftnnrtes's 
 jrgdniaed torm. The grounds upon which this conclusion 
 "rests will never be shaken, for the close similarity between 
 man and the lower animals in embryonic development, 
 as well as in innumerable points of structure and constitu- 
 tion, both of high and of the most trifling importance the 
 rudiments which he retains, and the abnormal reversions to 
 which he is occasionally liable are facts which cannot be 
 disputed. They have long been known, but. until recently, 
 they told us nothing with respect to the origin of man. 
 Now, when viewed by the light of our knowledge of the 
 whole organic world, their meaning is unmistakable. The 
 great principle of evolution stands up clear and firm when 
 these groups of facts are considered in connection with.
 
 694 THE DESCENT OF MAN. 
 
 others, such as the mutual affinities of the members of the 
 same group, their geographical distribution in past and 
 present times, and their geological succession. It is incredi- 
 ble that all these facts should speak falsely. He who is not 
 content to look, like a savage, at the phenomena of nature 
 as disconnected, cannot any longer believe that man is the 
 work of a separate act of creation. He will be forced to 
 admit that the close resemblance of the embryo of man to 
 that, for instance, of a dog the construction^ his skull, 
 limbs and whole frame on the same plan with that of other 
 mammals, independently of the uses to which the parts 
 may be put the occasional reappearance of various 
 structures, for instance of several muscles, which man 
 does not normally possess, but which are common to i;Le 
 Quadrumana and a crowd of analogous facts all point 
 in the plainest manner to the conclusion that man is 
 the co - descendant with other mammals of a common 
 progenitor. 
 
 We have seen that man incessantly presents individual 
 
 differences in all parts of his body and in his mental 
 
 faculties. These differences or variations seem to be 
 
 ./induced by the same general causes, and to obey the same 
 
 i laws as with the lower animals. In both cases similar laws 
 
 inheritance prevail. Man tends to increase at a greater 
 rate than his means of subsistence; consequently he is occa- 
 sionally subjected to a severe struggle for existence, and 
 natural selection will have effected whatever lies within its 
 scope. A succession of strongly marked variations of a 
 similar nature is by no means requisite; slight fluctuating 
 differences in the individual suffice for the work of natural 
 selection; not that we have any reason to suppose that in 
 the same species all parts of the organization tend to vary 
 to the same degree. We may feel assured that the inherited 
 effects of the long-continued use or disuse of parts will 
 have done much in the same direction with natural select 
 tion. Modifications formerly of importance, though no 
 longer of any special use, are long-inherited. When one 
 part is modified other parts change through the principle 
 of correlation, of which we have instances in many curious 
 cases of correlated monstrosities. Something may be 
 attributed to the direct and definite action of the surround- 
 ing conditions of life, such as abundant food, heat or 
 moisture; and, lastly, many characters of slight physio-
 
 GENERAL SUMMARY AND CONCLUSION. 695 
 
 logical importance, some indeed of considerable importance, 
 have been gained through sexual selection. 
 
 No doubt man, as well as every other animal, presents 
 structures, which seem to our limited knowledge, not to be 
 now of any service to him, nor to have been so formerly, 
 either for the general conditions of life, or in the relations 
 of one sex to the other. Such structures cannot be 
 accounted for by any form of selection, or by the inherited 
 effects of the use and disuse of parts. We know, however, 
 that many strange and strongly marked peculiarities of 
 structure occasionally appear in our domesticated- produc- 
 tions, and if their unknown causes were to act more uni- 
 formly, they would probably become common to all the 
 individuals of the species. We may hope hereafter to 
 understand something about the causes of such occasional 
 modifications, especially through the study of monstrosities; 
 hence, the labors of experimentalists, such as those of M. 
 Camille Dareste, are full of promise for the future. In 
 general we can only say that the cause of each slight varia- 
 tion and of each monstrosity lies much more in the con- 
 stitution of the organism than in the nature of the sur- 
 rounding conditions; though new and changed conditions 
 certainly play an important part in exciting organic 
 changes of many kinds. 
 
 Through the means just specified, aided perhaps by 
 others as yet undiscovered, man lias been raised to his 
 present state. But since he attained to the rank of man- 
 hood, he has diverged into distinct races, or, as they may 
 be more fitly called, sub-species. Some of these, such as 
 the negro and European, are so distinct that, if specimens 
 had been brought to a naturalist without any further in- 
 formation, they would undoubtedly have been considered 
 by him as good and true species. Nevertheless, all the 
 races agree in so many unimportant details of structure and 
 in so many mental peculiarities that these can be ac- 
 counted for only by inheritance from a common progenitor; 
 and a progenitor thus characterized would probably deserve 
 to rank as man. 
 
 It must not be supposed that the divergence of each race 
 from the other races and of all from a common stock can 
 be traced back to any one pair of progenitors. On the con- 
 trary, at every stage in the process of modification, all the 
 individuals which were in any way better fitted for their
 
 696 THE DESCENT OF MAN. 
 
 conditions of life, though in different degrees, would have 
 survived in greater numbers than the less well-fitted. The 
 process would have been like that followed by man, when 
 he does not intentionally select particular individuals, but 
 breeds from all the superior individuals and neglects the 
 inferior. He thus slowly but surely modifies his stock and 
 unconsciously forms a new strain. So with respect to 
 modifications acquired independently of selection, and due 
 to variations arising from the nature of the organism and 
 the action of the surrounding conditions, or from changed 
 habits of life, no single pair will have been modified much 
 more than the other pairs inhabiting the same country, for 
 all will have been continually blended through free inter- 
 crossing. 
 
 By considering the embryological structure of man the 
 homologies which he presents with the lower animals the 
 rudiments which he retains and the reversions to which 
 he is liable, we can partly recall in imagination the former 
 condition of our early progenitors; and can approximately 
 place them in their proper place in the zoological series. 
 d 
 
 We thus learn that man is descended from a hfliry 
 quadruped, probably arboreal in its haloits and an inhabi- 
 tant 6t the Old World. This creature if its whole 
 " " 
 
 ~5Tu"creia een examine y a nauras, wou ave 
 foeen Classed among the (^uadrumana, as surely as the still 
 more anr-icMrrpTTrgeuTtor of the~01d_aiid JN'ew World Inon- 
 keys. Tliti Qlindi umaua aud all the higher mammals are" 
 
 this through a long line of diversified forms, from some 
 amphibian-like creature, and this again from some fish-like 
 animal. In the dim obscurity of the past we can see that 
 the early progenitor of all the Vertebrata must have been an 
 aquatic animal, provided with branchiae, with the two sexes 
 united in the same individual, and with the most important 
 organs of the body (such as the brain and heart) imper- 
 fectly or not at all developed. This animal seems to have 
 been more like the larvae of the existing marine Ascidians 
 than any other known form. 
 
 The high standard of our intellectual powers and moral dis- 
 position is the greatest difficulty which presents itself, after 
 we have been driven to this conclusion on the origin of 
 man. But every one who admits the principle of evolution
 
 GENERAL SUMMARY AND CONCLUSION. 697 
 
 must see that the mental powers of the higher animals, 
 which are the same in kind with those of man, though so 
 different in degree, are capable of advancement. Thus 
 the interval between the mental powers of one of the 
 higher apes and of a fish, or between those of an ant and 
 scale-insect, is immense ; yet their development does not 
 offer any special difficulty ; for with our domesticated 
 animals the mental faculties are certainly variable, and 
 the variations are inherited. No one doubts that they are 
 of the utmost importance to animals in a state of nature. 
 Therefore, the conditions are favorable for their develop- 
 ment through natural selection. The same conclusion 
 may be extended to man; the intellect must have been all- 
 important to him, even at a very remote period, as enabling 
 him to invent and use language, to make weapons, tools, 
 traps, etc., whereby with the aid of his social habits he 
 long ago became the most dominant of all living creatures. 
 
 A great stride in the development of the intellect will 
 have followed, as soon as the half -art and half -instinct 
 of language came into use; for the continued use of lan- 
 guage will have reacted on the brain and produced an 
 inherited effect; and this again will have reacted on the 
 improvement of language. As Mr. Chauncey Wright* has 
 well remarked, the largeness of the brain in man relatively 
 to his body, compared with the lower animals, may be 
 attributed in chief part to the early use of some simple 
 form of language that wonderful engine which affixes 
 signs to all sorts of objects and qualities, and excites trains 
 of thought which would never arise from the mere impression 
 of the senses, or if they did arise could not be followed out. 
 The higher intellectual powers of man, such as those of 
 ratiocination, abstraction, self-consciousness, etc., probably 
 follow from the continued improvement and exercise of the 
 other mental faculties. 
 
 The development of the moral qualities is a more inter- 
 esting problem. The foundation lies in the social instincts, 
 including under this term the family ties. These instincts 
 are highly complex, and in the case of the lower animals 
 give special tendencies toward certain definite actions; but 
 the more important elements are love and the distinct 
 
 * " On the Limits of Natural Selection," in the " North American 
 Koview," Oct., 1870, p. 295.
 
 698 THE DESCENT OF MAN. 
 
 emotion of sympathy. Animals endowed with the social 
 instincts take pleasure in one another's company, warn one 
 another of danger, defend and aid one another in many 
 ways. These instincts do not extend to all the individuals 
 of the species, but only to those of the same community. 
 As they are highly beneficial to the species they have in all 
 probability been acquired through natural selection. 
 
 A moral being is one who is capable of reflecting on his 
 past actions and their motives of approving of some and 
 disapproving of others; and the fact that man is the one 
 being who certainly deserves this designation is the great- 
 est of all distinctions between him and the lower animals. 
 But in the fourth chapter I have endeavored to show that 
 the moral sense follows, firstly, from the enduring and ever- 
 present nature of the social instincts; secondly, from man's 
 appreciation of the approbation and disapprobation of his 
 fellows; and, thirdly, from the high activity of his mental 
 faculties, with past impressions extremely vivid; and in 
 these latter respects he differs from the lower animals. 
 Owing to this condition of mind, man cannot avoid look- 
 ing both backward and forward and comparing past im- 
 pressions. Hence after some temporary desire or passion 
 has mastered his social instincts, lis reflects and compares 
 the now weakened impression of such past impulses with 
 the ever-present social instincts ; and he then feels that 
 sense of dissatisfaction which all unsatisfied instincts leave 
 behind them, he therefore resolves to act differently for 
 the future and this is conscience. Any instinct perma- 
 nently stronger or more enduring than another gives rise 
 to a feeling which we express by saying that it ought to be 
 obeyed. A pointer dog if able to reflect on his past con- 
 duct would say to himself, I ought (as indeed we say of 
 him) to have pointed at that hare and not have yielded to 
 the passing temptation of hunting it. 
 
 Social animals are impelled partly by a wish to aid the 
 members of their community in a general manner, but 
 more commonly to perform certain definite actions. Man 
 is impelled by the same general wish to aid his fellows; 
 but has few or no special instincts. He differs also from 
 the lower animals in the power of expressing his desires by 
 words, which thus become a guide to the aid required and 
 bestowed. The motive to give aid is likewise much modi- 
 fied in man; it no longer consists solely of a blind instinct-
 
 GENERAL SUMMARY AND CONCGLUSION". 701 
 
 ive impulse, but is much influenced by tbd at in this work 
 of his fellows. The appreciation ancLrreligious; but he 
 praise and blame both rest on s^ipo-ow w hy it is more irre- 
 as we have seen, is 0110 of th<- most i-^ ;i distiuct^^-ies by 
 the social instincts. Sympathy, though gaineu as an iii->.. 
 stinct, is also much strengthened by exercise or habit. As 
 all men desire their own happiness, praise or blame is 
 bestowed on actions and motives according as they lead to 
 this end; and as happiness is an essential part of the gen- 
 eral good the greatest-happiness principle indirectly serves 
 as a nearly safe standard of right and wrong. As the rea- 
 soning powers advance and experience is gained the remoter 
 effects of certain lines of conduct on the character of the 
 individual and on the general good are perceived; and then 
 the self-regarding virtues come within the scope of public 
 opinion and receive praise and their opposites blame. But 
 with the less civilized nations reason often errs, and many 
 bad customs and base superstitions come within the same 
 scope and are then esteemed as high virtues and their 
 breach as heavy crimes. 
 
 The moral faculties are generally and justly esteemed as 
 of higher value than the intellectual powers. But we 
 should bear in mind that the activity of the mind in vividly 
 recalling past impressions is one of the fundamental though 
 secondary bases of conscience. This affords the strongest 
 argument for educating and stimulating in all possible 
 ways the intellectual faculties of every human being. No 
 doubt a man with a torpid mind, if his social affections and 
 sympathies are well developed, will be led to good actions, 
 and may have a fairly sensitive conscience. But whatever 
 renders the imagination more vivid and strengthens the 
 habit of recalling and comparing past impressions will make 
 the conscience more sensitive, and may even somewhat 
 compensate for weak social affections and sympathies. 
 
 The moral nature of man has reached its present stand- 
 ard partly through the advancement of his reasoning powers 
 and consequently of a just public opinion, but especially 
 from his" sympathies having been rendered more tender and 
 widely diffused through the effects of habit, example, 
 instruction and reflection. It is not improbable that after 
 long practice virtuous tendencies may be inherited. AVith 
 the more civilized races the conviction of the existence of 
 an all-seeing Deity has had a potent influence on the
 
 -THE DESCENT OF MAN. 
 
 emotion of sym^ ultimately man does not accept the 
 instincts take ple,^ his f e ii we as his sole guide, though 
 another of danger, ^-i^ JK . f his habitual convictions, con- 
 ways.^ T^ese instmctf ord hilli - h(i ;:l f egt rule . His con- 
 Qeience then becomes the supreme judge and monitor. 
 Nevertheless, the first foundation or origin of the moral sense 
 lies in the social instincts, including sympathy; and these 
 instincts no doubt were primarily gained, as in the case of 
 the lower animals, through natural selection. 
 
 The belief in God has often been advanced as not only 
 the greatest but the most complete of all the distinctions 
 between man and the lower animals. It is, however, im- 
 possible, as we have seen, to maintain that this belief is 
 innate or instinctive in man. On the other hand, a belief 
 in all-pervading spiritual agencies seems to be universal; 
 and apparently follows from a considerable advance in 
 man's reason, and from a still greater advance in his 
 faculties of imagination, curiosity and wonder. I am 
 aware that the assumed instinctive belief in God has been 
 used by many persons as an argument for His existence. 
 But this is a rash argument, as we should thus be compelled 
 to believe in the existence of many cruel and malignant 
 spirits, only a little more powerful than man; for the 
 belief in them is far more general than in a beneficient Deity. 
 The idea of a universal and beneficient Creator -does not 
 seem to arise in the mind of man until he has been elevated 
 by long-continued culture. 
 
 He who believes in the advancement of man from some 
 low organized form will naturally ask, How does this bear 
 on the belief in the immortality of the soul? The barbar- 
 ous races of man, as Sir L Lubbock has shown, possess no 
 clear belief of this kind ; but arguments derived from the 
 primeval beliefs of savages are, as we have just seen, of 
 little or no avail. Few persons feel any anxiety from the 
 impossibility of determining at what precise period in the 
 development of the individual, from the first trace of a 
 minute germinal vesicle, man becomes an immortal being; 
 and there is no greater cause for anxiety because the 
 period cannot possibly be determined in the gradually 
 ascending organic scale.* 
 
 * The Rev. J. A. Picton gives a discussion to this efiwt in hi8 
 " New Theories and the Old Faith," 1870.
 
 GENERAL SUMMA*.* 7 AND CONCL USION. 701 
 
 I am aware that the conclusions arrived at in this work 
 will be denounced by some as highly irreligious; but he 
 who denounces them is bound to show why it is more irre- 
 ligious to explain the origin of man as a distinct species by 
 descent from some lower form, through the laws of varia- 
 tion and natural selection, than to explain the birth of the 
 individual through the laws of ordinary reproduction. 
 The birth both of the species and of the individual are equally 
 parts of that grand sequence of events, which our minds 
 refuse to accept as the result of blind chance. The under- 
 standing revolts at such a conclusion, whether or not we 
 are able to believe that every slight variation of structure, 
 the union of each pair in marriage, the dissemination of 
 each seed, and other such events have all been ordained for 
 some special purpose. 
 
 Sexual selection has been treated at great length in this 
 work; for, as I have attempted to show, it has played an 
 important part in the history of the organic world. I am 
 aware that much remains doubtful, but I have endeavored 
 to give a fair view of the whole case. In the lower divis- 
 ions of the animal kingdom sexual selection seems to have 
 done nothing; such animals are often affixed for life to the 
 same spot, or have the sexes combined in the same indi- 
 vidual, or, what is still more important, their perceptive and 
 intellectual faculties are not sufficiently advanced to allow 
 of the feelings of love and jealousy, or of the exertion of 
 choice. When, however, we come to the Arthropoda and 
 Yertebrata, even to the lowest classes in these two great 
 sub-kingdoms, sexual selection has effected much. 
 
 In the several great classes of the animal kingdom in 
 mammals, birds, reptiles, fishes, insects and even crusta- 
 ceans the differences between the sexes follow nearly the 
 same rules. The males are almost always the wooers; and 
 they alone are armed with special weapons for fighting with 
 their rivals. They are generally stronger and larger than 
 the females, and are endowed with the requisite qualities 
 of courage and pugnacity. They are provided, either 
 exclusively or in a much higher degree than the females, 
 with organs for vocal or instrumental music, and with 
 odoriferous glands. They are ornamented with infinitely 
 diversified appendages, and with the most brilliant or con- 
 spicuous colors, often arranged in elegant patterns, while
 
 70;i THE DESCENT OF MAN. 
 
 the females are unadorned. When the sexes differ in more 
 important structures it is the male which is provided with 
 special sense-organs for discovering the female, with loco- 
 motive organs for reaching her, and often with prehensile 
 organs for holding her. These various structures for charm- 
 ing or securing the female are often developed in the male 
 during only part of the year; namely, the breeding-season. 
 They have in many cases been more or less transferred to 
 the females; and in the latter case they often appear in her 
 as mere rudiments. They are lost or never gained by the 
 males after emasculation. Generally they are not developed 
 in the male during early youth, but appear a short time 
 before the age for reproduction. Hence, in most cases the 
 young of both sexes resemble each other; and the female 
 somewhat resembles her young offspring throughout life. 
 In almost every great class a few anomalous cases occur, 
 where there has been an almost complete transposition of 
 the characters proper to the two sexes; the females assum- 
 ing characters which properly belong to the males. This 
 surprising uniformity in the laws regulating the differences 
 between the sexes in so many and such widely separated 
 classes is intelligible if we admit the action of one common 
 cause; namely, sexual selection. 
 
 Sexual selection depends on the success of certain indi- 
 viduals over others of the same sex, in relation to the prop- 
 ' agation of the species; while natural selection depends on 
 i the success of both sexes, at all ages, in relation to the gen- 
 \eral conditions of life. The sexual struggle is of two 
 Kinds; in the one it is between the individuals of the same 
 sex, generally the males, in order to drive away or kill their 
 rivals, the females remaining passive; while in the other, 
 the struggle is likewise between the individuals of the 
 same sex, in order to excite or charm those of the opposite 
 sex, generally the females, which no longer remain passive, 
 but select the more agreeable partners. This latter kind 
 of selection is closely analogous to that which man unin- 
 tentionally, yet effectually, brings to bear on his domesti- 
 cated productions, when he preserves during a long period 
 the most pleasing or useful individuals, without any wish to 
 modify the breed. 
 
 The laws of inheritance determine whether characters 
 gained through sexual selection by either sex shall be trans- 
 mitted to the same sex, or to both; as well as the age at
 
 GENERAL SUMMARY AND CONCLUSION. 703 
 
 which they shall be developed. It appears that variations 
 arising late in life are commonly transmitted to one and 
 the same sex. Variability is the necessary basis for the 
 action of selection and is wholly independent of it. It fol- 
 lows from this, that variations of the same general nature 
 have often been taken advantage of and accumulated 
 through sexual selection in relation to the propagation of 
 the species, as well as through natural selection in relation 
 to the general purposes of life. Hence secondary sexual 
 characters, when equally transmitted to both sexes, can be 
 distinguished from ordinary specific characters only by the 
 light of analogy. The modifications acquired through 
 sexual selection are often so strongly pronounced that the 
 two sexes have frequently been ranked as distinct species, 
 or even as distinct genera. Such strongly marked differ- 
 ences must be in some manner highly important; and we 
 know that they have been acquired in some instances at 
 the cost not only of inconvenience, but of exposure to 
 actual danger. 
 
 The belief in the power of sexual selection rests chiefly 
 on the following considerations. Certain characters are 
 confined to one sex; and this alone renders it probable that 
 in most cases they are connected with the act of reproduc- 
 tion. In innumerable instances these characters are fully 
 developed only at maturity, and often during only a part of 
 the year, which is always the breeding-season. The males 
 (passing over a few exceptional cases) are the more active 
 in courtship; they are the better armed, and are rendered 
 the more attractive in various ways. It is to be especially 
 observed that the males display their attractions with 
 elaborate care in the presence of the females; and that 
 they rarely or never display them excepting during the 
 season of love. It is incredible that all this should be pur- 
 poseless. Lastly, we have distinct evidence with some 
 quadrupeds and birds that the individuals of one sex are 
 capable of feeling a strong antipathy or preference for 
 certain individuals of the other sex. 
 
 - Bearing in mind these facts and the marked results of 
 man's unconscious selection when applied to domesticated 
 animals and cultivated plants it seems to me almost cer- 
 tain that if the individuals of one sex were during a long ^ 
 series of generations to prefer pairing with certain indi- j 
 viduals of the other sex, characterized in some peculiar I
 
 704 THE DESCENT OF MAN. 
 
 manner, the offspring would slowly but surely become 
 modified in this same manner. I have not attempted to 
 conceal that, excepting when the males are more numerous 
 than the females, or when polygamy prevails, it is doubtful 
 how the more attractive males succeed in leaving a larger 
 number of offspring to inherit their superiority in orna- 
 ments or other charms than the less attractive males; but 
 I have shown that this would probably follow from the 
 females especially the more vigorous ones, which would 
 be the first to breed preferring not only the more attract- 
 ive but at the same time the more vigorous and victorious 
 males. 
 
 Although we have some positive evidence that birds 
 appreciate bright and beautiful objects, as with the bower- 
 birds of Australia, and although they certainly appreciate 
 the power of song, yet I fully admit that it is astonishing 
 that the females of many birds and some mammals should 
 be endowed with sufficient taste to appreciate ornaments 
 which we have reason to attribute to sexual selection; and 
 this is even more astonishing iu the case of reptiles, fish 
 and insects. But we really know little about the minds of 
 the lower animals. It cannot be supposed, for instance, that 
 male birds of paradise or peacocks should take such pains 
 in erecting, spreading and vibrating their beautiful plumes 
 before the females for no purpose. We should remember 
 the fact given on excellent authority in a former chapter 
 that several peahens, when debarred from an admired male, 
 remained widows during a whole season rather than pair 
 with another bird. 
 
 Nevertheless, I know of no fact in natural history more 
 wonderful than that the female Argus pheasant should 
 appreciate the exquisite shading of the ball-and-socket 
 ornaments and the elegant patterns on the wing-feathers 
 of the male. He who thinks that the male was created as 
 he now exists must admit tbat the great plumes, which 
 prevent the wings from being used for flight and which 
 are displayed during courtship and at no other time in a 
 manner quite peculiar to this one species, were given to 
 him as an ornament. If so, he must likewise admit that 
 the female was created and endowed with the capacity of 
 appreciating such ornaments. I differ only in the convic- 
 tion that the male Argus pheasant acquired his beauty 
 gradually, through the preference of the females during
 
 GENERAL S UMMAR 7 AND CONGL USION 705 
 
 many generations for the more highly ornamented males; 
 the esthetic capacity of the females having been advanced 
 through exercise or habit just as our own taste is gradually 
 improved. In the male, through the fortunate chance of a 
 few feathers being left unchanged, we can distinctly trace 
 how simple spots with a little fulvous shading on one side 
 may have been developed by small steps into the wonderful 
 ball-and-socket ornaments; and it is probable that they 
 were actually thus developed. 
 
 Every one who admits the principle of evolution, and 
 yet feels great difficulty in admitting that female mammals, 
 birds, reptiles and fish, could have acquired the high taste 
 implied by the beauty of the males, and which generally 
 coincides with our own standard, should reflect that the 
 nerve-cells of the brain in the highest as well as in the 
 lowest members of the Vertebrate series, are derived from 
 those of the common progenitor of this great kingdom. 
 For we can thus see how it has come to pass that certain 
 mental faculties, in various and widely distinct groups of 
 animals, have been developed in nearly the same mannei 
 and to nearly the same degree. 
 
 The reader who has taken the trouble to go through the 
 several chapters devoted to sexual selection will be able to 
 judge how far the conclusions at which I have arrived are 
 supported by sufficient avidence. If be accepts these con- 
 clusions he may, I think, safely extend them tc mankind, 
 but it would be superfluous here to repeat what I have so 
 lately said on the manner in which sexual selection appar- 
 ently has acted on man, both on the male and female side, 
 causing the two sexes to differ in body and mind, and the 
 several races to differ from each other in various characters, 
 as well as from their ancient and lowly organized pro- 
 genitors. 
 
 He who admits the principle of sexual selection will be 
 led to the remarkable conclusion that the nervous system 
 not only regulates most of the existing functions of the 
 body, but has indirectly influenced the progressive develop- 
 ment of various bodily structures and of certain mental 
 qualities. Courage, pugnacity, perseverance, strength and 
 size of body, weapons of all kinds, musical organs, both 
 vocal and instrumental, bright colors and ornamental ap- 
 pendages, have all been indirectly gained by the one sex or 
 the other, through the exertion of choice, the influence of
 
 ?06 THE DESCENT OF MAN. 
 
 love and jealousy and the appreciation of the beautiful in 
 sound, color or form; and these powers of the mind mani- 
 festly depend on the development of the brain. 
 
 Man scans with scrupulous care the character and pedi- 
 gree of his horses, cattle and dogs before he matches them; 
 
 I but when he comes to his own marriage he rarely, or never, 
 
 ' takes any such care. He is impelled by nearly the same 
 motives as -the lower animals, when they are left to their 
 
 ( own free choice, though he is in so far superior to them 
 that he highly values mental charms and virtues. On the 
 other hand he is strongly attracted by mere wealth or rank. 
 Yet he might by selection do something not only for the 
 bodily constitution and frame of his offspring, but for their 
 intellectual and moral qualities. Both sexes ought to re- 
 frain from marriage if they are in any marked degree in- 
 ferior in body or mind; but such hopes are Utopian and 
 will never be even partially realized until the laws of in- 
 heritance are thoroughly known Every one does good 
 service, who aids toward this end. When the principles of 
 breeding and inheritance are better understood, we shall 
 not hear ignorant member; of our legislature rejecting with 
 , scorn a plan for ascertaining whether or not consanguineous 
 
 ymarriages are injurious to man. 
 
 The advancement of the welfare of mankind is a most 
 intricate problem; all ought to refrain from marriage who 
 cannot avoid abject poverty for their children; for poverty 
 is not only a grea'; evii. but tends to its own increase by 
 "eading to recklessness h, marriage On the other hand, 
 as Mr. Gal ton has remarked, if the prudent avoid marriage, 
 while the reckless marry, the inferior members tend to 
 supplant the better members of society. Man, like every 
 other animal, has no doubt advanced to his present high 
 condition through a struggle for existence consequent on 
 his rapid multiplication; and if he is to advance still higher, 
 it is to be feared that he must remain subject to a severe 
 struggle. Otherwise he would sink into indolence, and the 
 more gifted men would not be more successful in the battle 
 of life than the less gifted. Hence our natural rate of 
 increase, though leading to many and obvious evils, must 
 not be greatly n'minished by any means. There should 
 be open competition for all men; :md the most able should 
 not be prevented by laws or customs from succeeding
 
 GENERAL SUMMARY AND CONCLUSION. 707 
 
 best and rearing the largest number of offspring. Impor- 
 tant as the struggle for existence has been and even still is, 
 yet as far as the highest part of man's nature is concerned'' 
 there are other agencies more important. For the moral 
 qualities are advanced, either directly or indirectly, much 
 more through the effects of habit, the reasoning powers, 
 instruction, religion, etc., than through natural selection; 
 though to this latter agency may be safely attributed the 
 social instincts which afforded the basis for the develop- 
 ment of the moral sense. 
 
 The main conclusion arrived at in this work, namely, 
 that man is descended from some lowly organized form, 
 will, I regret to think, be highly distasteful to many. But 
 there can hardly be a doubt that we are descended from 
 barbarians. The astonishment which I felt on first seeing 
 a party of Fuegians on a wild and broken shore will never 
 be forgotten by me, for the reflection at once rushed into 
 my mind <euch were our ancestors. These men were 
 absolutely naked and bedaubed with paint, their long hair 
 was tangled, their mouths frothed with excitement, and 
 their expression was wild, startled and distrustful. They 
 possessed hardly any arts, and like wild animals lived on 
 what they could catch; they had no government, and were 
 merciless to every one not of their own small tribe. He 
 who has seen a savage in bis native land will not feel much 
 shame, if forced to acknowledge that the blood of some 
 more humble creature flows in his veins. For my own part 
 I would as soon be descended from that heroic little mon- 
 key who braved his dreaded enemy in order to save the 
 life of his keeper, or from that old baboon, who, descend- 
 ing from the mountains, carried away in triumph his 
 young comrade from a crowd of astonished dogs as from 
 a savage who delights to torture his enemies, offers up 
 bloody sacrifices, practices infanticide without remorse, 
 treats his wives like slaves, knows no decency, and is 
 haunted by the grossest superstitions. 
 
 Man may be excused for feeling some pride at having 
 risen, though not through his own exertions, to the very 
 summit of the organic scale; and the fact of his having 
 thus risen, instead of having been aboriginally placed there, 
 may give him hope for a still higher destiny in the distant 
 future. But we are not here concerned with hopes or fears,
 
 703 THE DESCENT OF MAN. 
 
 only with the truth as far as our reason permits us to dis- 
 cover it: and I have given the evidence to the best of my 
 f Sv -abiliiij>' We must, however, acknowledge, as it seems to 
 me, that man, with all his noble qualities, with sympathy 
 which feels for the most debased, with benevolence which 
 / extends not only to other men but to the humblest living 
 / creature, with his godlike intellect which has penetrated 
 / into the movements and constitution of the solar system 
 / with all these exalted powers man still bears in his bodily 
 / frame the indelible stamp of his lowly origin.
 
 SUPPLEMENTAL NOTE. 
 
 SUPPLEMENTAL NOTE 
 
 ON 
 
 SEXUAL SELECTION IN RELATION TO MONKEYS. 
 [Reprinted from Nature, November 2, 1876, p. 18.] 
 
 IN the discussion on sexual selection in my " Descent of 
 Man;" no case interested and perplexed me so much as the 
 brightly colored hinder ends and adjoining parts of certain 
 monkeys. As these parts are more brightly colored in one 
 sex than the other, and as they become more brilliant 
 during the season of love, I concluded that the colors had 
 been gained as a sexual attraction. I was well aware that 
 I thus laid myself open to ridicule; though in fact it is not 
 more surprising that a monkey should display his bright- 
 red hinder ena than that a peacock should display his mag- 
 nificent tail. I had, however, at that time no evidence of 
 monkeys exhibiting this part of their bodies during their 
 courtship ; and such display in the case of birds 
 affords the best evidence that the ornaments of the 
 males are of service to them by attracting or 
 exciting the females. I have lately read an article 
 by Joh. von Fischer, of Gotha, published in "Der f 
 Zoologische Garten," April, 1876, on the expression of 
 monkeys under various emotions, which is well worthy of 
 study by any one interested in the subject, and which 
 shows that the author is a careful and acute observer. In 
 this article there is an account of the behavior of a young 
 male mandrill when he first beheld himself in a looking- 
 glass, and it is added that after a time he turned round 
 and presented his red hinder end to the glass. Accord- 
 ingly I wrote to Herr J. von Fischer to ask what he sup- 
 posed was the meaning of this strange action, and he has 
 sent me two long letters full of new and curious details, 
 which will, I hope, be hereafter published. He says that
 
 710 THE DESCENT OF MAN. 
 
 he was himself at first perplexed by the above action, and 
 was thus led carefully to observe several individuals of 
 various other species of monkeys, which he has long kept 
 in his house. He finds that not only the mandrill (Cyno- 
 cephalus mormon] but the drill ( C'. leucoplmus] and three 
 other kinds of baboons (CJiamadryas sphinx and babouin), 
 also Cynopithecus niger, and Macacus rhesus and nemes- 
 trinus, turn this part of their bodies, which in all these 
 species is more or less brightly colored, to him when they 
 are pleased, and to other persons as a sort of greeting. He 
 took pains to cure a Macacus rhesus, which he had kept 
 for five years, of this indecorous habit, and at last suc- 
 ceeded. These monkeys are particularly apt to act in this 
 manner, grinning at the same time, when first introduced 
 to a new monkey, but often also to their old monkey 
 friends; and after this mutual display they begin to play 
 together. The young mandrill ceased spontaneously after 
 a time to act in this manner toward his master, Von 
 Fischer, but continued to do so toward persons who were 
 strangers and to new monkeys. A young Cynopithecus 
 niger never acted, excepting on one occasion, in this way 
 toward his master, but frequently toward strangers, 
 and continues to do so up to the present time. From 
 these facts Von Fischer concludes thalf the monkeys 
 which behaved in this manner before a looking-glass 
 (viz., the mandrill, drill, Cynopithecus niger, Maca- 
 cus rhesus and nemestrinus) acted as if their reflec- 
 tion were a new acquaintance. The mandrill and drill, 
 which have their hinder ends especially ornamented, 
 display it even while quite young, more frequently and 
 more ostentatiously than do the other kinds. Next in 
 order comes Cynocephalus hamadruus, while the other 
 species act in this manner seldomer. The individuals, 
 however, of the same species vary in this respect, and some 
 which were very shy never displayed their hinder ends. It 
 deserves especial attention that Von Fischer has never 
 seen any species purposely exhibit the hinder part of its 
 body, if not at all colored. This remark applies to many 
 individuals of Macacus cynomolgus and Cercocelus radi- 
 atus (which is closely allied to M. rhesus), to three species 
 of Cercopithecus and several American monkeys. The 
 habit of turning the hinder ends as a greeting to an old 
 friend or new acquaintance, which seems to us so odd, is
 
 SUPPLEMENTAL NOTE. 711 
 
 not really more so than the habits of many savages, for 
 instance that of rubbing their bellies with their hands, or 
 rubbing noses together. The habit with the mandrill and 
 drill seems to be instinctive or inherited, as it was followed 
 by very young animals; but it is modified or guided, like 
 so many other instincts, by observation, for Von Fischer 
 says that they take pains to make their display fully; and 
 if made before two observers, they turn to him who seems 
 to pay the most attention. 
 
 With respect to the origin of the habit, Von Fischer 
 remarks that his monkeys like to have their naked hinder 
 ends patted or stroked, and that they then grunt with 
 pleasure. They often also turn this part of their bodies 
 to other monkeys to have bits of dirt picked off, and so 
 no doubt it would be with respect to thorns. But the 
 habit with adult animals is connected to a certain extent 
 with sexual feelings, for Von Fischer watched through a 
 glass door a female Cynopitliecus niger, and she, during 
 several days, "umdretite und dem Miinnchen mit gur- 
 gelnden Tonen die stark gerothete Sitzflache zeigte, was 
 ich friiher nie an diesem Thier bemerkt hatte. Beim 
 Anblick dieses Gegenstandes erregte sich das Mannchen 
 sichtlich, denn es polterte heftig an den Staben, ebenfalls 
 gurgelnde Laute ausstossend." As all the monkeys which 
 have the hinder parts of their bodies more or less brightly 
 colored live, according to Von Fischer, in open rocky 
 places, he thinks that these colors serve to render one sex 
 conspicuous at a distance to the other; but as monkeys are 
 such gregarious animals I should have thought that there 
 was no need for the sexes to recognize each other at a dis- 
 tance. It seems to me more probable that the bright 
 colors, whether on the face or hinder end, or, as in the 
 mandrill, on both, serve as a sexual ornament and attrac- 
 tion. Anyhow, as we now know that monkeys have the 
 habit of turning their hinder ends toward other monkeys, 
 it ceases to be at all surprising that it should have been 
 this part of their bodies which bas been more or less 
 decorated. The fact that it is only the monkeys thus 
 characterized which, as far as at present known, act in this 
 manner as a greeting toward other monkeys renders it 
 doubtful whether the habit was first acquired from some 
 independent cause, and that afterward the parts in ques- 
 tion were colored as a sexual ornament; or whether the
 
 712 THE DESCENT OF MAN. 
 
 coloring and the habit of turning round were first acquired 
 through variation and sexual selection, and that afterward 
 the habit was retained as a sign of pleasure or as a greet- 
 ing through the principle of inherited association. This 
 principle apparently comes into play on many occasions; 
 thus it is generally admitted that the songs of birds serve 
 mainly as an attraction during the season of love, and that 
 the leks, or great congregations of the black grouse, are 
 connected with their courtship; but the habit of singing 
 has been retained by some birds when they feel happy, for 
 instance, by the common robin, and the habit of congre- 
 gating has been retained by the black grouse during other 
 seasons of the year. 
 
 I beg leave to refer to one other point in relation to 
 sexual selection. It has been objected that this form of 
 selection, as far as the ornaments of the males are con- 
 cerned, implies that all the females within the same dis- 
 trict must possess and exercise exactly the same taste. It 
 should, however, be observed, in the first place, that 
 although the range of variation of a species may be very 
 large it is by no means indefinite. I have elsewhere given a 
 good instance of this fact in the pigeon, of which there are 
 at least a hundred varieties differing widely in their colors, 
 and at least a score of varieties of the fowl differing in 
 the same kind of way; but the range of color in these 
 two species is extremely distinct. Therefore the females of 
 natural species cannot have an unlimited scope for their 
 taste. In the second place, I presume that no supporter of 
 the principle of sexual selection believes that the females 
 select particular points of beauty in the males; they are 
 merely excited or attracted in a greater degree by one male 
 than by another, and this seems often to depend, especially 
 with birds, on brilliant coloring. Even man, excepting 
 perhaps an artist, does not analyze the slight differences in 
 the features of the woman whom he may admire, on which 
 her beauty depends. The male mandrill has not only the 
 hinder end of his body, but his face gorgeously colored and 
 marked with oblique ridges,, a yellow beard and other orna- 
 ments. We may infer from what we see of the variation 
 of animals under domestication that the above several 
 ornaments of the mandrill vere gradually acquired by one 
 individual varying a little in one way and another indi- 
 vidual iii another way. The males which were the hand-
 
 SUPPLEMENTAL NOTE. 713 
 
 somest or the most attractive in any manner to the females 
 would pair oftenest, and would leave rather more offspring 
 than other males. The offspring of the former, although 
 variously intercrossed, would either inherit the peculiarities 
 of their fathers or transmit an increased tendency to vary 
 in the same manner. Consequently the whole body of 
 males inhabiting the same country would tend from the 
 effects of constant intercrossing to become modified almost 
 uniformly, but sometimes a little more in one character and 
 sometimes in another, though at an extremely slow rate; all 
 ultimately being thus rendered more attractive to the 
 females. The process is like that which I have called 
 unconscious selection by man, and of which I have given 
 several instances. In one country the inhabitants value a 
 fleet or light dog or horse, and in another country a heavier 
 and more powerful one; in neither country is there any 
 selection of individual animals with lighter or stronger 
 bodies and limbs; nevertheless, after a considerable lapse 
 of time, the individuals are found to have been modified in 
 the desired manner almost uniformly, though differently in 
 each country. In two absolutely distinct countries inhab- 
 ited by the same species, the individuals of which can 
 never, during long ages, have intermigrated and inter- 
 crossed, and where, moreover, the variations will probably 
 not have been identically the same, sexual selection might 
 cause the males to differ. Nor does the belief appear to 
 me altogether fanciful that two sets of females, surrounded 
 by a very different environment, would be apt to acquire 
 somewhat different tastes with respect to form, sound or 
 color. However this may be, I have given in my " Descent 
 of Man" instances of closely allied birds inhabiting dis- 
 tinct countries, of which the young and the females cannot 
 be distinguished, while the adult males differ considerably, 
 and this may be attributed with much probability to the 
 action of sexual selection.
 
 INDEX. 
 
 Abbott, C., on the battles of seals, 571. 
 
 Abductor of tlie fifth metatarsal, presence of, in man, 47. 
 
 Abercrombie, Dr. , on disease of the brain affecting speech, 100. 
 
 Abipones, marriage customs of the, 683. 
 
 Abortion, prevalence of the practice of, 52. 
 
 Abou-Simbel, caves of, 191. 
 
 Abramis brama, 282. 
 
 Abstraction, power of, in animals, 93. 
 
 AcalUs, stridulation of, 346. 
 
 Acanthodactylus capensis, sexual differences of color in, 405. 
 
 Accentor modularis, 539. 
 
 Acclimatization, difference of, in different races of men, 191. 
 
 Achetidae, stridulation of the, 320, 321, 323; rudimentary stridulat* 
 ing organs in female, 326. 
 
 Acilius sulcatus, elytra of the female, 313. 
 
 Acomus, development of spurs in the female of, 512. 
 
 Acridiidse, stridulation of the, 320, 324; rudimentary stridulating 
 organs in female, 326. 
 
 Acromio-basilar muscle, and quadrupetal gait, 47. 
 
 Acting, 203. 
 
 Actinia, bright colors of, 294. 
 
 Adams, Mr., migration of birds, 122; intelligence of nut-hatch, 
 466; on the Bombycilla carolinensis, 525. 
 
 Admiral butterfly, 353. 
 
 Adoption of the young of other animals by female monkeys, 79. 
 
 Advancement in the organic scale, Von Baer's definition of, 186. 
 
 Aeby, on the difference between the skulls of man and the 
 quadrumana, 170. 
 
 Esthetic faculty, not highly developed in savages, 105. 
 
 Affection, maternal, 79; manifestation of, by animals, 79; parental 
 and filial, partly the result of natural selection, 120; mutual, of 
 birds, 467; shown by birds in confinement, for certain persons, 467. 
 
 Africa, probably the birthplace of man, 177; South, crossed popu- 
 lation of, 198. South, retention of color by the Dutch in, 219; South, 
 portion of the sexes in the butterflies of, 283; tattooing practiced 
 
 , 654; Northern, coiffure of natives of, 655. 
 
 Agassiz L., on conscience in dogs, 117; on the coincidence of the 
 races of man with zoological provinces, 193; on the number of 
 species of man, 198; on the courtship of the land-snails, 297; on the 
 brightness of the colors of male fishes during the breeding- season, 
 385; on the frontal protuberance of the males of Oeophagus and 
 Cichla, 385, 392; male fishes hatching ova in their mouths, 391; 
 
 -C
 
 716 INDEX. 
 
 sexual differences in color of chromids, 392; on the slight sexual 
 differences of the South Americans, 640; on the tattooing of the 
 Amazonian Indians, 657. 
 
 Age, in relation to the transmission of characters in birds, 528; 
 variation in accordance with, in birds, 551. 
 
 Agelceus pho&niceus, 255, 472. 
 
 Ageronia feronia, noise produced by, 349. 
 
 Agrion, dimorphism in, 328, 829. 
 
 Agrion Hambuni, sexes of, 328. 
 
 Agrionidae, difference in the sexes of, 328. 
 
 Agrotis exclamatioms, 358. 
 
 Ague, tertian, dog suffering from, 8. 
 
 Ainos, hairiness of the, 639. 
 
 Aitchison, Mr., on sheep, 279. 
 
 AUhurus polytmus, young of, 555. 
 
 Albino birds, 476. 
 
 Alca torda, young of, 553. 
 
 Alces palmata, 587. 
 
 Alder and Hancock, MM., on the nudi-branch mollusca, 298. 
 
 Allen, J. A., vigor of birds earliest hatched, 240, 241; effect of 
 difference of temperature, light, etc., on birds, 254, colors of birds, 
 480; on the relative size of the sexes of Callorhinus urtdnus, 588; on 
 the name of Otaria jubata, 594; on the pairing of seals, 596; on 
 sexual differences in the color of bats, 610; Allen, S., on the habits 
 of Hoplopterus, 414; on the plumes of Herons, 444; on the vernal 
 moult of Herodias biibulcus, 445. 
 
 Alligator, courtship of the male, 250, 398; roaring of the male, 
 646. 
 
 Amadavat, pugnacity of male, 416. 
 
 Amadina Lathami, display of plumage by the male, 456; amadina 
 castanotis, display of plumage by the male, 455. 
 
 Amazons, butterflies of the, 283; fishes of the, 389. 
 
 America, variation in the skulls of aborigines of, 29; wide range 
 of aborigines of, 193; lice of the natives of, 193; general beardless- 
 ness of the natives of, 639; North, butterflies of, 283; Indians of, 
 women a cause of strife among the, 640; Indians of, their notions of 
 female beauty, 659, 662; South, character of the natives of, 191; 
 population of parts of, 197; piles of stone in, 204; extinction of the 
 fossil horse of, 218, desert birds of, 558; slight sexual difference of 
 the aborigines of, 640; prevalence of infanticide in, 675. 
 
 American languages, often highly artificial, 103. 
 
 Americans, wide geographical range of, 33; native, variability of, 
 198; and negroes, difference of, 224; aversion of, to hair on the face, 
 662. 
 
 Ammophila, on the jaws of, 312. 
 
 Ammotragm tragelaphus, hairy forelegs of, 606, 609. 
 
 Amphibia, affinity of, to the ganoid fishes, 180; vocal organs of 
 the, 646. 
 
 Amphibians, 187, 394; breeding while immature, 551. 
 
 Amphioxus, 181. 
 
 Amphipoda, males sexually mature while young, 552. 
 
 Amunoph III, negro character of features of, 192. 
 
 Anal appendages of insects, 313.
 
 INDEX. 717 
 
 Analogous variation in the plumage of birds, 488. 
 
 Anas, 525; anas acuta, male plumage of, 446; anas boschas, male 
 plumage of, 446; anas histrionica, 552; anas punctata, 425. 
 
 Anastomus oscitans, sexes and young of, 553; white nuptial plum- 
 age of, 560. 
 
 Anatidse, voices of, 425. 
 
 Anaxjunius, differences in the sexes of, 328. 
 
 Andaman islanders, susceptible to change of climate, 214. 
 
 Anderson, Dr., on the tail of Macacus brunneus, 66; the Bufo 
 nkimmensis, 396; sounds of EcMs carinata, 400. 
 
 Andrana fulva, 331. 
 
 Anglo-Saxons, estimation of the beard among the, 663. 
 
 Animals, domesticated, more fertile than wild, 50; cruelty of 
 savages to, 133; characters common to man and, 166; domestic, 
 change of breeds of, 680. 
 
 Annelida, 299; colors of, 299. 
 
 Anobium tessellatum, sounds produced by, 347. 
 
 Anolis cristatellus, male, crest of, 401; pugnacity of the male, 401; 
 throat-pouch of, 402. 
 
 Anser canadensis, 473; anser cygnoides, 471; knob at the base of 
 the beak of, 484; anser hyperboreus, whiteness of, 560. 
 
 Antelope, prong-horned, horns of, 265. 
 
 Antelopes, generally polygamous, 246; horns of, 265, 575; canine 
 teeth of some male, 572; use of horns of, 580; dorsel crests in, 606; 
 dewlaps of, 608; winter change of two species of, 619; peculiar 
 markings of, 621. 
 
 Antennae, furnished with cushions in the male of Penthe, 313. 
 
 Anthidium manicatum, large male of, 316. 
 
 Anthocharis cardamines, 350, 354 ; sexual difference of color in, 
 364; anthocharis gemitia, 354; anthocharis sara, 354. 
 
 Anthophora acervorum, large male of, 316 ; anthophora retusct, 
 difference of the sexes in, 331. 
 
 Anthropidse, 173. 
 
 AntJius, molting of, 444. 
 
 Antics of birds, 431. 
 
 Antigua, Dr. Nicholson's observations on yellow fever in, 222. 
 
 Antilocapra americana, horns of, 265, 575, 578. 
 
 Antilope bezoartica, horned females of, 575, 577, 578; sexual differ- 
 ence in the color of, 611 ; antilope Dorcas euchore, 575. 
 
 Antilope euchore, horns of, 580; antilope montana, rudimentary 
 canines in the young male of, 586; antilope niger, sing-sing, caama 
 and gorgon, sexual differences in the colors of, 612; antilope oreas, 
 horns of, 265; antilope saiga, polygamous habits of, 246; antilope 
 strepsiceros, horns of, 265; antilope subgutturosa, absence of suborbital 
 pits in, 604. 
 
 Antipathy, shown by birds in confinement, to certain persons, 467. 
 
 Ants, 167; large size of cerebral ganglia in, 60; soldier, large jaws 
 of, 70; playing together, 77; memory in, 83; intercommunication of, 
 by means of the antennae, 101; habits of; 167 ; difference of the 
 sexes in, 330; recognition of each other by, after separation, 330; 
 white, habits of, 330. 
 
 Anura, 395. 
 
 Apatania muliebris, male unknown, 287.
 
 718 INDEX. 
 
 Apathus, difference of the sexes in, 331. 
 
 Apatura Iris, 348, 350. 
 
 Apes, difference of the young, from the adult, 9; semi-erect atti- 
 tude of some, 58; mastoid processes of, 59; influences of the jaw- 
 muscles on the physiognomy of, 60; female, destitute of large 
 canines, 71; building platforms, 93; imitative faculties of, 146; 
 3, 175; 
 
 anthropomorphous, 175; probable speedy extermination of the, 177; 
 Gratiolet on the evolution of, 202; canine teeth of male, 572; 
 females of some, less hairy beneath than the males, 686; long- 
 armed, their mode of progression, 58. 
 
 Aphasia, Dr. Baternan on, 100. 
 
 Apis mellifica, large male of, 316. 
 
 Apollo, Greek statues of, 663. 
 
 Apoplexy in Cebm Azarce, 7. 
 
 Appendages, anal, of insects, 313. 
 
 Approbation, influence of the love of, 124, 132, 148. 
 
 Aprosmictus scapulatus, 521. 
 
 Apm, proportion of sexes, 287. 
 
 Aquatic birds, frequency of white plumage in, 561. 
 
 Aqutta chrynaetos, 463. 
 
 Arab women, elaborate and peculiar coiffure of, 666. 
 
 Arabs, fertility of crosses with other races, 195; gashing of cheeks 
 and temples among the, 655. 
 
 Arachnida, 307. 
 
 Arakhan, artificial widening of the forehead by the natives 
 of, 665. 
 
 Arboricola, young of, 533. 
 
 Archeopteryx, 180. 
 
 Arctiidse, coloration of the, 356. 
 
 Ardea asha, rufescens and ccerulea, change of color in, 562, 563; 
 ardea ccerulea, breeding in immature plumage, 552; ardea gularis,. 
 change of plumage in, 563; ardea herodias, love-gestures of the male, 
 431; ardea ludoviciana, age of mature plumage in, 551; continued 
 growth of crest and plumes in the male of, 552; ardea nycticorax, 
 cries of, 417. 
 
 Ardeola, young of, 534. 
 
 Ardetta, changes of plumage in, 524. 
 
 Argenteuil, 24. 
 
 Argus pheasant, 435, 457, 526; display of plumage by the male, 
 451; ocellated spots of the, 488; gradation of characters in the, 494. 
 
 Argyll, Duke of, on the physical weakness of man, 71; the fash- 
 ioning of implements peculiar to man, 92; on the contest in man 
 between right and wrong, 141; on the primitive civilization of man, 
 162; on the plumage of the male Argus pheasant, 451; on Urosticte 
 Benjamini, 503; on the nests of birds, 515. 
 
 Argynnis, coloring of the lower surface of, 356. 
 
 Aricoris epitus, sexual differences in the wings of, 314. 
 
 Aristocracy, increased beauty of the, 669. 
 
 Arms, proportions of, in soldiers and sailors, 36; direction of the 
 hair on the, 177; and hands, free use of, indirectly correlated with 
 diminution of canines, 60. 
 
 Arrest of development, 40, 41. 
 
 Arrow-heads, stone, general resemblance of, 203-
 
 INDEX. 719 
 
 Arrows, use of, 203. 
 
 Arteries, variations in the course of the, 30. 
 
 Artery, effect of tying, upon the lateral channels, 36. 
 
 Arthropoda, 299. 
 
 Arts practiced by savages, 203. 
 
 Ascension, colored incrustation on the rocks of, 298. 
 
 Ascidia, affinity of the lancelet to, 181; tadpole-like larvae of, 181. 
 
 Ascidians, 296; bright colors of some, 295. 
 
 Asinus, Asiatic and African species of, 626; asinus taeniopus, 626. 
 
 Ass, color- variations of the, 626. 
 
 Ateles, effects of brandy on an, 8; absence of the thumb in, 57-, 
 ateles beelzebuth, ears of 16; ateles marginatus, color of the ruff of 
 613; hair on the head of, 627. 
 
 Ateuchus cicatricosus, habits of, 340. 
 
 Ateuchus, stridulation of, 346. 
 
 Athalia, proportions of the sexes in, 286. 
 
 Atropus pulsatorius, 330. 
 
 Attention, manifestations of, in animals, 83. 
 
 Audouin, V., on a hymenopterous parasite with a sedentary male, 
 251. 
 
 Audubon, J. J., on the pinioned goose, 119 ; on the speculum of 
 Mergus cucullatus, 267; on the pugnacity of male birds, 411, 414; 
 on courtship of Caprirnulgus, 416; on Tetrao cupido, 417; on Ardea 
 nycticorax, 417; on Sturnella ludoviciana, 417; on the vocal organs 
 of Tetrao cupido, 422; on the drumming of the male Tetrao umbel- 
 lus, 426; on sounds produced by the nightjar, 426, 427; on Ardea 
 herodias and Cathartes jota, 431, 432; on Mimus polyglottus, 686; on 
 display in male birds, 447; on the spring change of color in some 
 finches, 446; on migration of mocking thrushes, 467; recognition of 
 a dog by a turkey, 468; selection of mate by female birds, 472; on 
 the turkey, 468; on variation in the male scarlet tanager, 481; on the 
 musk-rat, 619; on the habits of Pyranga &stiva, 515; on local differ- 
 ences in the nests of the same species of birds, 519; on the habits of 
 woodpeckers, 521 ; on Bombycilla carolinensis, 525 ; on young 
 females of Pyranga cestiva acquiring male characters, 525; on the 
 immature plumage of thrushes, 530; on the immature plumage of 
 birds, 530; et seq., on birds breeding in immature plumage, 551; on 
 the growth of the crest and plumes in the male Ardea ludoviciana, 
 551; on the change of color in some species of Ardea, 562. 
 
 Audubon and Bachman, MM., on squirrels fighting, 570; on the 
 Canadian lynx, 594. 
 
 Aughey, Prof., on rattlesnakes, 401. 
 
 Austen, N. L., on Anolis cristatellus, 401. 
 
 Australia, not the birthplace of man, 176; half-castes killed by the 
 natives of, 194; lice of the natives of, 193. 
 
 Australia, South, variation in the skulls of aborigines of, 28. 
 -Australians, color of new-born children of, 636; relative height of 
 the sexes of, 638; women a cause of war among the, 640. 
 
 Axis deer, sexual difference in the color of the, 612. 
 
 Aymaras, measurements of the, 39; no grey hair among the, 637; 
 hairlessness of the face in the, 639; long hair of the, 662. 
 
 Azara, on the proportion of men and women among the Quaranys, 
 276; on Palamedea cornuta, 412; on the beards of the Quaranys,
 
 720 INDEX. 
 
 639; on strife for women among the Guanas, 640 ; on infanticide, 
 659, 675; on the eradication of the eyebrows and eyelashes by the 
 Indians of Paraguay, 662; on polyandry among the Guanas, 677; celi- 
 bacy unknown among the savages of South America, 678; on the 
 freedom of divorce among the Charruas, 683. 
 
 Babbage, C., on the greater proportion of illegitimate female 
 births, 276. 
 
 Babirusa, tusks of the, 592. 
 
 Baboon, revenge in a, 78; rage excited in, by reading, 80; mani- 
 festation of memory by a, 83; employing a mat for shelter against 
 the sun, 93; protected from punishment by its companions, 117; 
 Cape, mane of the male, 594; Hamadryas, mane of the male, 594. 
 
 Baboon, effects of intoxicating liquors on, 8; ears of, 17; diversity 
 of the mental faculties in, 30; hands of, 56; habits of, 57; variability 
 of the tail in, 65; manifestation of maternal affection by, 79; using 
 stones and sticks as weapons, 92 ; co-operation of, 115 ; silence of, 
 on plundering expeditions, 118; apparent polygamy of, 245; polyga- 
 mous and social habits of, 674. 
 
 Baboons, courtship of, 710. 
 
 Bachman, Dr., on the fertility of mulattoes, 194. 
 
 Baer, K . E. von, on embryonic development, 9 ; definition of 
 advancement in the organic scale, 186. 
 
 Bagehot, W., on the social virtues among primitive men, 132; 
 slavery formerly beneficial, 133; on the value of obedience, 147; on 
 human progress, 150; on the persistence of savage tribes in classical 
 times, 208. 
 
 Bailey, E. M., on the mode of fighting of the Italian buffalo, 580; 
 on the fighting of stags, 582. 
 
 Bain, A., on the sense of duty, 111; aid springing from sympathy, 
 116; on the basis of sympathy, 120; on the love of approbation, etc., 
 124; on the idea of beauty, 667. 
 
 Baird, W. , on a difference in color between the males and females 
 of some Entozoa, 294. 
 
 Baker, Mr. , observation on the proportion of the sexes in pheas- 
 ant-chicks, 280; Sir S., on the fondness of the Arabs for discordant 
 music, 431; on sexual difference in the colors of an antelope, (512; 
 on the elephant and rhinoceros attacking white or grey horses, 617; 
 on the disfigurements practiced by the negroes, 617; on the gashing 
 of the cheeks and temples practiced in Arab countries, 655; on the 
 coiffure of the North Africans* 656; on the perforation of the lower 
 lip by the women of Latooka, 656; on the distinctive characters of 
 the coiffure of central African tribes, 656; on the coiffure of Arab 
 women, 666. 
 
 " Balz " of the black cock, 412, 460. 
 
 Bantam, Sebright, 239, 270. 
 
 Banteng, horns of, 576 ; sexual differences in the colors of the, 
 612. 
 
 Banyal, color of the, 661. 
 
 Barbarism, primitive, of civilized nations, 162. 
 
 Barbs, filamentous, of the feathers, in certain birds, 437, 489. 
 
 Barr, Mr., on sexual preference in dogs, 598. 
 
 Barrago, F. , on the Simian resemblances of man, 3. 
 
 Barrington, Daines, on the language of birds, 97; on the duckling
 
 INDEX. 721 
 
 of the lien, 418; on the object of the song of birds, 419; on the sing- 
 ing of female birds, 420; on birds acquiring the songs of other 
 birds, 420; on the muscles of the larynx in song birds, 421; on the 
 want of the power of song by female birds, 513. 
 
 Barrow, on the widow-bird, 457. 
 
 Bartels, Dr., supernumerary mammae in men, 42. 
 
 Bartlett, A. D., period of" hatching of bird's eggs, 187; on the 
 tragopan, 249; on the development of the spurs in Crossoptilon 
 auritum, 267; on the fighting of the males of Plectropterus yamben 
 sis, 414; on the knot, 444; on display in male birds, 447; on the dis- 
 play of plumage by the male Polyplectron, 449 ; on Crossoptilon 
 auritum and Phasianus Wallichii, 454; on the habits of Lophophorus, 
 477; on the color of the mouth in Buceros bicornis, 484; on the incu- 
 bation of the cassowary, 544; on the Cape Buffalo, 580; on the use 
 of the horns of antelopes, 580; on the fighting of male wart-hogs, 
 593; on Ammotragus tragelaphus, 606; on the colors of Cercopithecus 
 cephus, 614; on the colors of the faces of monkeys, 629; on the 
 naked surfaces of monkeys, 686. 
 
 Bartlett, on courting of Argus pheasant, 454. 
 
 Bartram, on the courtship of the male allegator, 398. 
 
 Basque language, highly artificial, 102. 
 
 Bate, C. S., on the superior activity of male Crustacea, 250; on the 
 proportions of the sexes in crabs, 288; on the chelae of Crustacea, 301; 
 on the relative size of the sexes in Crustacea, 302; on the colors of 
 Crustacea, 306. 
 
 Bateman, Dr., tendency to imitation in certain diseased states, 82; 
 on Aphasia, 100. 
 
 Bates, H. W. , on variations in the form of the head of Amazonian 
 Indians, 32; on the proportion of sexes among Amazonian butter- 
 flies, 283; on sexual diiferences in the wings of butterflies, 314; on 
 the field-cricket, 321; on Pyrodes pulcherrimus, 333; on the horns of 
 Lamellicorn beetles, 334, 336; on the colors of Epicalice, etc., 350; on 
 the coloration of tropical butterflies, 352: on the variability of Papilio 
 Sesostris and Children, 362; on male and female butterflies inhabit- 
 ing different stations, 364; on mimicry, 366; on the caterpillar of a 
 Sphinx, 369; on the vocal organs of the umbrella-bird, 423; on the 
 toucans, 560; on Brachyurus calmis, 629. 
 
 Batokas, knocking out two upper incisors, 656. 
 
 Batrachia, 395; eagerness of male, 250. 
 
 Bats, scent-glands, 604; sexual differences in the color of, 610; fur 
 of male frugivorous, 610. 
 
 Battle, law of, 163; among beetles, 339; among birds, 408; among 
 mammals, 570 et seq.; in man, 640. 
 
 Beak, sexual difference in the forms of the, 408; in the color of 
 the, 435. 
 
 Beaks, of birds, bright colors of, 559. 
 
 'Beard, development of, in man, 636; analogy of the, in man and 
 the quadrumana, 636; variation of the development of the, in dif- 
 ferent races of men, 637; estimation of, among bearded nations 663; 
 probable origin of the, 688; in monkeys, 171; of mammals, 607 
 
 Beautiful, taste for the, in birds, 466; in the quadrumana, 617. 
 
 Beauty, sense of, in animals, 104; appreciation of, by birds, 469; 
 influence of , 654, 657; variability of the standard of, 681; sense of, 
 sufficiently permanent for action of sexua.l selection, 563, 712.
 
 722 INDEX. 
 
 Beavan, Lieut. , on the development of the horns in Cervus Eldi, 265 
 
 Beaver, instinct and intelligence of the, 75, 77; voice of the, 602. 
 castoreurn of the, 604. 
 
 Beavers, battles of male, 570. 
 
 Bechstein, on female birds choosing the best singers among the 
 males, 418; on rivalry in song-birds, 419; on the singing of female 
 birds, 420; on birds acquiring the songs of other birds, 420; on pair- 
 ing the canary and siskin, 472; on a sub- variety of the monk pigeon, 
 472; on spurred hens, 511. 
 
 Beddoe, Dr., on causes of difference in stature, 35. 
 
 Bee-eater, 421. 
 
 Bees, 118; pollen-baskets and stings of, 70; destruction of drones 
 and queens by, 120; female, secondary sexual characters of, 235; 
 proportion of sexes, 286; difference of the sexes in color and sexual 
 selection, 331. 
 
 Beetle, luminous larva of a, 314. 
 
 Beetles, 333; size of the cerebral ganglia in, 61 ; dilatation of the 
 fore tarsi in male, 312; blind, 833; stridulation of, 341. 
 
 Belgium, ancient inhabitants of, 207. 
 
 Bell, Sir C., on the emotional muscles in man, 4; " snarling mus- 
 cles," 46; on the hand, 57; Bell, T., on the numerical proportion of 
 the sexes in moles, 279; on the newts, 394; on the croaking of the 
 frog, 395; on the difference in the coloration of the sexes in Zootoca 
 vivipara, 405; on moles fighting, 570. 
 
 Bell-bird, sexual difference in the color of the, 440. 
 
 Bell-birds, colors of, 560. 
 
 Belt, Mr., on the nakedness of tropical mankind, 64; on a spider- 
 monkey and eagle, 115; habits of ants, 168; Lampyridae distasteful 
 to mammals, 314; mimicry of Leptalides, 368; colors of Nicaragua!! 
 frogs, 396; display of humming-birds, 503; on the toucans, 560; pro- 
 tective coloring of skunk, 621. 
 
 Benevolence manifested by birds, 467. 
 
 Bennett, A. W., attachment of mated birds, 466; on the habits of 
 Dromaeus irroratus, 545; Bennett, D., on birds of paradise, 449. 
 
 Berbers, fertility of crosses with other races, 195. 
 
 Bernicla antarctica, colors of, 560. 
 
 Bernicle gander pairing with a Canada goose, 471. 
 
 Bert, M., crustaceans distinguish colors, 306. 
 
 Bettoni, E., on local differences in the nests of Italian birds, 519. 
 
 Beyle, M., see Bombet. 
 
 Bhoteas, color of the beard in, 637. 
 
 Bhringa, disciform tail-feathers of, 445. 
 
 Bianconi, Prof., on structures as explained through mechanical 
 principles, 27. 
 
 Bibio, sexual differences in the genus, 317. 
 
 Bichat, on beauty, 667. 
 
 Bickes, proportion of sexes in man, 274. 
 
 Bile, colored in many animals, 296. 
 
 Bimana, 170. 
 
 Birds, imitations of the songs of other birds by, 82; dreaming, 84; 
 killed by telegraph wires, 90; language of, 97; sense of beauty in, 
 104; pleasure of, in incubation, 119; male, incubation by, 185; and 
 reptiles, alliance of, 17; sexual differences in the beak of some, 236;
 
 INDEX. 723 
 
 migratory, arrival of the male before the female, 241; apparent rela- 
 tion between polygamy and marked sexual differences in, 248; 
 monogamous, becoming polygamous under domestication, 249; 
 eagerness of male in pursuit of the female, 250; wild, numerical 
 proportion of the sexes in, 280; secondary sexual characters of, 407; 
 difference of size in the sexes of, 411; fights of male, witnessed by 
 females, 414; display of male, to captivate the females, 416; close 
 attention of, to the songs of others, 418; acquiring the song of their 
 foster parents, 420; brilliant, rarely good songsters, 421; love-antics 
 and dances of, 431; coloration of, 438 et seq.; moulting of, 442 et seq.; 
 unpaired, 462; male, singing out of season, 465; mutual affection of, 
 466; in confinement, distinguish persons, 467; hybrid, production of, 
 470; Albino, 476; European, number of species of, 479; variability 
 of, 479; geographical distribution of coloring, 480; gradation of 
 secondary sexual characters in, 488; obscurely colored, building con- 
 cealed nests, 516; young female, acquiring male characters, 525; 
 breeding in immature plumage, 551; moulting of, 551; aquatic, fre- 
 quency of white plumage in, 561; vocal courtship of, 646; naked 
 skin of the head and neck in, 686. 
 
 Birgus latro, habits of, 305. 
 
 Birkbeck, Mr. , on the finding of new mates by golden eagles, 463. 
 
 Birthplace of man, 176. 
 
 Births, numerical proportions of the sexes in, in animals and 
 man, 243, 244; male and female, numerical proportion of, in England, 
 274. 
 
 Bischoff, Prof., on the agreement between the brains of man and 
 of the orang, 6; figure of the embryo of the dog, 11; on the convo- 
 lutions of the brain in the human fetus, 10; on the difference 
 between the skulls of man and the quadrumana, 170; resemblance 
 between the ape's and man's, 227. 
 
 Bishop, J., on the vocal organs of frogs, 397; on the vocal organs 
 of corvine birds, 421 ; on the trachea of the Merganser, 425. 
 
 Bison, American, co-operation of, 115; mane of the male, 594. 
 
 Bitterns, dwarf, coloration of the sexes of, 524. 
 
 Biziura Idbata, musky odor of the male, 407; large size of male, 
 411. 
 
 Blackbird, sexual differences in the, 248; proportion of the sexes 
 in the, 281; acquisition of a song by, 421; color of the beak in the 
 sexes of the, 435, 559; pairing with a thrush, 470; colors and nidifi- 
 cation of the, 517; young of the, 554, 555; sexual difference in colora- 
 tion of the, 559. 
 
 Black-buck, Indian, sexual difference in the color of the, 612. 
 
 Blackcap, arrival of the male, before the female, 240; young of 
 the, 554. 
 
 Black-cock, polygamous, 248; proportion of the sexes in the, 279; 
 pugnacity and love-dance of the, 412; call of the, 425 ; moulting of 
 the, 444; duration of the courtship of the, 460 ; and pheasant, 
 hybrids of, 125; sexual difference in coloration of the, 559; crimson 
 eye-cere of the, 559. 
 
 Black-grouse, characters of young, 530, 537. 
 
 Blacklock, Dr., on music, 653. 
 
 Black wall, J., on the speaking of the magpie, 101; on the deser- 
 tion of their young by swallows, 122; on the superior activity of
 
 724 INDEX. 
 
 male spiders, 250; on the proportion of the sexes in spiders, 287; on 
 sexual variation of color in spiders, 307; on male spiders, 307. 
 
 Bladder-nose Seal, hood of the, 603. 
 
 Elaine, on the affections of dogs, 597. 
 
 Blair, Dr. , on the relative liability of Europeans to yellow fever, 
 221. 
 
 Blake, C. C., on the jaw from La Naulette, 46. 
 
 Blakiston, Capt., on the American snipe, 428; on the dances of 
 Tetrao phasianellus, 431. 
 
 Blasius, Dr. , on the species of European birds, 480. 
 
 Bledius taurus, hornlike processes of male, 338. 
 
 Bleeding, tendency to profuse, 268. 
 
 Blenkiron, Mr., on sexual preference in horses, 598. 
 
 Blennies, crest developed on the head of male, during the breeding 
 season, 385. 
 
 Blethisa multipunctata, stridulation of, 343. 
 
 Bloch, on the proportions of the sexes in fishes, 281. 
 
 Blood, arterial, red color of, 296; pheasant, number of spurs in. 
 413. 
 
 Blow-fly, sounds made by, 318. 
 
 Bluebreast, red-throated, sexual differences of the, 537. 
 
 Blumenbach, on Man, 32; on the large size of the nasal cavities in 
 American aborigines, 38; on the position of man, 170; on the number 
 of species of man, 199. 
 
 Blyth, E., on the structure of the hand in the species of Hylobates, 
 57; observations on Indian crows, 116; on the development of the 
 horns in the Koodoo and Eland antelopes, 265; on the pugnacity of 
 the males of Oallicrex cristatns, 409; on the presence of spurs in the 
 female Euplocamus erythrophthalmus, 413; on the pugnacity of the 
 amadavat, 415; on the spoonbill, 425; on the moulting of Anthus, 
 444; on the moulting of bustards, plovers, and GaUus bankiva, 445; 
 on the Indian honey-buzzard, 481 ; on sexual differences in the 
 the color of the eyes of hornbills, 483; on Oriolus melanocephalus, 
 524; on Palceornis javanicus, 525; on the genus Ardetta, 524; on the 
 peregrine falcon, 525; on young female birds acquiring male charac- 
 ters, 524; on the immature plumage of birds, 529; on representative 
 species of birds, 533; on the young of Turnix, 543; on anomalous 
 young of Lanius rufus and Colymbus ylacialis, 550; on the sexes 
 and young of the sparrows, 550; on dimorphism in some herons, 552; 
 on the ascertainment of the sex of nestling bullfinches by pulling 
 out breast feathers, 551; on orioles breeding in immature plumage, 
 552; on the sexes and young of Buphus and Anastomus, 553; on the 
 young of the blackcap" and blackbird, 554, 555; on the young of the 
 stonechat, 555; on the white plumage of Anastomus, 561; on the 
 horns of Bovine animals, 575; on the horns of Antilope bezoartica, 
 575, 577; on the mode of fighting of Ovis cycloceros, 579; on the voice 
 of the Gibbons, 602; on the crest of the male wild goat, 606; on the 
 colors of Portax picta, 611; on the colors of Antilope bezoartica, 612; 
 on the color of the Axis deer, 613; on sexual difference of color in 
 Hylobates hoolock, 613 ; on the hog-deer, 624 ; on the beard and 
 whiskers in a monkey becoming white with age, 637. 
 
 Boar, wild, polygamous in India, 246; use of the tusks by the, 
 685; fighting of, 591.
 
 INDEX. 7554 
 
 Boardman, Mr., Albino birds in U. S., 476. 
 
 Boitard and Corbie, MM., on the transmission of sexual peculiari- 
 ties in pigeons, 261; on the antipathy shown by some female pigeons 
 to certain males, 474. 
 
 Bold, Mr., on the singing of a sterile hybrid canary, 419. 
 
 Bombet, on the variability of the standard of beauty in Europe, 
 681. 
 
 Bombus, difference of the sexes in, 331. 
 
 Bombycida?, coloration of, 355; pairing of the, 360, colors of, 361. 
 
 Bombycttla carolinensis, red appendages of, 525. 
 
 Bombyx cynthia, 315; proportion of the sexes in, 282, 285; pairing 
 of, 360; bombyx mori, difference of size of the male and female 
 cocoons of, 315; pairing of, 360; bombyx pern yi, proportion of sexes 
 of, 285; bombyx yamamai, 315; M. Personal on, 283; proportion of 
 sexes of, 285. 
 
 Bonaparte, C. L., on the call-notes of the wild turkey, 435. 
 
 Bond, F., on the finding of new mates by crows, 463. 
 
 Bone, implements of, skill displayed in making, 55. 
 
 Boner, C., on the transfer of male characters to an old female 
 chamois, 574; on the habits of stags, 587; on the pairing of red deer, 
 595. 
 
 Bones, increase of, in length and thickness, when carrying a 
 greater weight, 36. 
 
 Boniz/j, P., difference of color in sexes of pigeons, 261. 
 
 Bonnet monkey, 171. 
 
 Bon wick, J., extinction of Tasmanians, 209. 
 
 Boomerang, 164. 
 
 Boreus hyemalis, scarcity of the male, 287. 
 
 Bory St. Vincent, on the number of species of man, 199; on the 
 colors of Labrus pavo, 388. 
 
 Bos etruseus, 576; bos gaurus, horns of, 576; bos moschatus, 604; 
 bos primigenius, 571; bos sondaicus, horns of, 576; colors of, 612. 
 
 Botocudos, 163; mode of life of, 224; disfigurement of the ears 
 and lower lip of the, 656. 
 
 Boucher de Perthes. J. C. de, on the antiquity of man, 2. 
 
 Bourbon, proportion of the sexes in a species of Papilio from, 283. 
 
 Bourien, on the marriage customs of the savages of the Malay 
 Archipelago, 683. 
 
 Bovidae, dewlaps of, 608. 
 
 Bower-birds, 461; habits of the, 432; ornamented playing-places 
 of, 104, 469. 
 
 Bows, use of, 203. 
 
 Brachycephalic structure, possible explanation of, 63. 
 
 Brachyura, 304. 
 
 Brachyurus calvus, scarlet face of, 629. 
 
 Bradley, Mr., abductor ossis metatarsi quinti in man, 47. 
 
 Brain, of man, agreement of the, with that of lower animals, 6; 
 convolutions of, in the human fetus, 10; influence of development 
 of mental faculties upon the size of the, 60; influence of the devel- 
 opment of, on the spinal column and skull, 62; larger in some exist' 
 ing mammals than in their tertiary prototypes, 91; relation of the 
 development of the, to the progress of language, 99; disease of the, 
 affecting speech, 99; difference in. tbe convolutions of, in different
 
 726 INDEX. 
 
 races of men, 191; supplement on, by Prof. Huxley, 227; develop- 
 ment of the gyri and sulci, 231. 
 
 Brakenridge, Dr., on the influence of climate, 36. 
 
 Brandt, A., on hairy men, 21. 
 
 Braubach, Prof., on the quasi-religious feeling of a dog toward 
 his master, 108; on the self-restraint of dogs, 117. 
 
 Brauer, F. , on dimorphism in Neurothemis, 329. 
 
 Brazil, skulls found in caves of, 192; population of, 197; compres- 
 sion of the nose by the natives of, 665. 
 
 Break between man and the apes, 177. 
 
 Bream, proportion of the sexes in the, 282. 
 
 Breeding, age of, in birds, 552; breeding season, sexual characters 
 making their appearance in the, in birds, 443. 
 
 Brehm, -on the effects of intoxicating liquors on monkeys, 8; on 
 the recognition of women by male Cynocephali, 8; on the diversity of 
 the mental faculties of monkeys, 31; on the habits of baboons, 57; 
 on revenge taken by monkeys, 78; on manifestations of maternal 
 affection by monkeys and baboons, 79; on the instinctive dread of 
 monkeys for serpents, 80; on the use of stones as missils by baboons, 
 92; on a baboon using a mat for shelter from the sun, 93; on the 
 signal-cries of monkeys, 98; on sentinels posted by monkeys, 114; on 
 co-operation of animals, 114; on an eagle attacking a young Cerco- 
 pithecus, 114; on baboons in confinement protecting one of their 
 number from punishment, 117; on the habits of baboons when 
 plundering, 108; on polygamy in Cynocephalus and Cebus, 246; on 
 the numerical proportion of the sexes in birds, 280; on the love- 
 dance of the blackcock, 412; Palamedea cwnuta, 414; on the habits 
 of the black-grouse, 416; on sounds produced by birds of paradise, 
 427; on assemblages of grouse, 460; on the finding of new mates by 
 birds, 464; on the fighting of wild boars, 591; on sexual differences 
 in Mycetes, 613; on the habits of Cynocephalus hamadryas, 674. 
 
 Brent, Mr., on the courtship of fowls, 473. 
 
 Breslau, numerical proportion of male and female births in, 275. 
 
 Bridgman, Laura, 99. 
 
 Brimstone butterfly, 354; sexual difference of color in the, 365. 
 
 British, ancient, tattooing practiced by, 655. 
 
 Broca, Prof., on the occurrence of the supra- condyloid foramen in 
 the human humerus, 24; anthropomorphous apes more bipedal than 
 quadrupedal, 59; on the capacity of Parisian skulls at different 
 periods, 61; comparison of modern and mediaeval skulls, 61; on tails 
 of quadrupeds, 65; on the influence of natural selection, 68; on 
 hybridity in man, 194; on human remains from Les Eyzies, 207; on 
 the cause of the difference between Europeans and Hindoos, 218. 
 
 Brodie, Sir B., on the origin of the moral sense in man, 111. 
 
 Bronn, H. G., on the copulation of insects of distinct species, 312. 
 
 Bronze period, men of, in Europe, 145. 
 
 Brown, R., sentinels of seals generally females, 114; on the bat- 
 tles of seals, 571; on the narwhal, 572; on the occasional absence of 
 the tusks in the female walrus, 572; on the bladder- nose seal, 603; on 
 the colors of the sexes in Phoca Grcenlandica, 611; on the apprecia- 
 tion of music by seals, 649; on plants used as love-philters, by North 
 American women, 659. 
 
 Browne, Dr. Crichton, injury to infants during parturition, 276.
 
 INDEX. 727 
 
 Brown- Sequard, Dr., on the inheritance of the effects of opera- 
 tions by guinea-pigs, 67, 689. 
 
 Bruce, on the use of the elephant's tusks, 578. 
 
 Brulerie, P. de la, on the habits of Ateuchus cicatricosua, 340; on 
 the stridulation of Ateuchus, 346. 
 
 Briinnich, on the pied ravens of the Feroe Islands, 482. 
 
 Bryant, Dr., preference of tame pigeon for wild mate, 475; Bry- 
 ant, Capt. , on the courtship of Callorhinus ursinus, 596. 
 
 Bubas bison, thoracic projection of, 337. 
 
 Bubulus caffer, use of horns, 580. 
 
 Bucephalus capensis, difference of the sexes of, in color, 398. 
 
 B-uceros, nidification and incubation of, 516 ; buceros bicornis, 
 sexual differences in the coloring of the casque, beak, and mouth in, 
 484; buceros corrugatus, sexual differences in the beak, 435. 
 
 Buchner, L., on the origin of man, 3; on the use of the human 
 foot as a prehensile organ, 58; on the mode of progession of the 
 apes, 58; on want of self-consciousness, etc., in savages, 94. 
 
 Bucholz, Dr., quarrels of chamaeleons, 405. 
 
 Buckinghamshire, numerical proportion of male and female births 
 in, 274. 
 
 Buckland, F., on the numerical proportion of the sexes in rats, 
 279; on the proportion of the sexes in the trout, 282; on Chimcera 
 monstrosn, 385. 
 
 Buckland, W., on the complexity of crinoids, 103. 
 
 Buckler, W., proportion of sexes of Lepidoptera reared by, 285. 
 
 Bucorax abyssinicus, inflation of the neck-wattle of the male 
 during courtship, 435. 
 
 Budytes Rail, 240. 
 
 Buffalo, Cape, 580; Indian, horns of the, 576; Italian, mode of 
 fighting of the, 580. 
 
 Buffon, on the number of species of man, 199. 
 
 Bufo sikimmenm, 396. 
 
 Bugs, 318. 
 
 Buist, R. , on the proportion of the sexes in salmon, 281 ; on the 
 pugnacity of the male salmon, 377. 
 
 Bulbul, pugnacity of the male, 409; display of under tail-coverts 
 by the male, 456. 
 
 Bull, mode of fighting of the, 579; curled frontal hair of the, 608. 
 
 Buller, Dr., on the Huia, 236; the attachment of birdo, 466. 
 
 Bullfinch, sexual differences in the, 248 ; piping, 418; female, 
 singing of the, 420; courtship of the, 455; widowed, finding a new 
 mate, 464; attacking a reed-bunting, 468; nestling, sex ascertained 
 by pulling out breast feathers, 551. 
 
 Bullfinches, distinguishing persons, 467; rivalry of female, 477. 
 
 Bulls, two young, attacking an old one, 115; wild, battles of, 571. 
 
 Bull-trout, male, coloring of, during the breeding-season, 386. 
 
 -Bunting, reed, head feathers of the male, 455; attacked by a bull- 
 finch, 468. 
 
 Buntings, characters of young, 529. 
 
 Buphus coromandus, sexes and young of, 553; change of color in, 
 563. 
 
 Burchell, Dr., on the zebra, 623; on the extravagance of a Bush- 
 woman in adorning herself, 658 ; celibacy unknown among the
 
 728 INDEX. 
 
 savages of South Africa, 678; on the marriage-customs of the Bush- 
 women, 684. 
 
 Burke, on the number of species of man, 199. 
 
 Burmese, color of the beard in, 687. 
 
 Burton, Capt., on negro ideas of female beauty, 660; on a universal 
 ideal of beauty, 664. 
 
 Bushmen, 72; marriage among, 684. 
 
 Bushwoman, extravagant ornamentation of a, 658. 
 
 Bush women, hair of, 191 ; marriage-customs of, 684. 
 
 Bustard, throat- pouch of the male, 423; humming noise produced 
 by a male, 429; Indian, ear-tufts of, 436. 
 
 Bustards, occurrence of sexual differences and of polygamy among 
 the, 248; love-gestures of the male, 432; double moult in, 443, 444. 
 
 Butler, A. G., on sexual differences in the wings of Aricoris epitus, 
 314; courtship, of butterflies, 348; on the coloring of the sexes in 
 species of Theda, 351; on ,the resemblance of Iphia-s glaucippe to a 
 leaf, 354; on the rejection of certain moths and caterpillars by lizards 
 and frogs, 370. 
 
 Butterfly, noise produced by a, 349; Emperor, 348, 350; meadow 
 brown, instability of the oscellated spots of, 486. 
 
 Butterflies, proportion of the sexes in, 283; forelegs atrophied in 
 some males, 314; sexual difference in the neuration of the wings of, 
 314; pugnacity of 'male, 348; protective resemblances of the lower 
 surface of, 353; display of the wings by, 356; white, alighting upon 
 bits of paper, 359; attracted by a dead specimen of the same species, 
 360; courtship of, 360; male and female inhabiting different stations, 
 364. 
 
 Buxton, C., observations on macaws, 115; on an instance of benev- 
 olence in a parrot, 467. 
 
 Buzzard, Indian honey, variation the crest of, 481. 
 
 Cabbage butterflies, 354. 
 
 Cachalot, large head of the male, 573. 
 
 Cadences, musical perception of, by animals, 648. 
 
 Caecum, 22; large, in the early progenitors of man, 182. 
 
 Cairina moschata, pugnacity of the male, 411. 
 
 Californian Indians, decrease of, 291. 
 
 Callianassa, chelae of, figured, 302. 
 
 CcMidryas, colors of sexes, 361 . 
 
 Callionymus lyra, characters of the male, 381. 
 
 Oallorhinus ur sinus, relative size of the sexes of, 588; courtship 
 of, 596. 
 
 Calotes maria, 406; Calotes nignlabris, sexual difference in the 
 color of, 405. 
 
 Cambridge, O. Pickard, on the sexes of spiders, 287; on the size of 
 male NephUa, 309. 
 
 Camel, canine teeth of male, 572, 586. 
 
 Campbell, J., on the Indian elephant, 246; on the proportion of 
 male and female births in the harems of Siam, 277. 
 
 Campylopterus hemileucurus, 281. 
 
 Canaries distingushing persons, 467. 
 
 Canary, polygamy of the, 249; change of plumage in, after moult- 
 ing, 269; female, selecting the best singing male, 418; sterile hybrid, 
 singing of a, 419; female, singing of the, 420; selecting a greenfinch, 
 472; and siskin, pairing of, 473.
 
 INDEX. 729 
 
 Cancer pagurus, 301. 
 
 Canestrini, G., on rudimentary characters and the origin of 
 man, 8: on rudimentary characters, 12; on the movement of the ear 
 in man, 15; on the variability of the vermiform appendage in man, 
 23; on the abnormal division of the malar bone in man, 44; on 
 abnormal conditions of the human uterus, 44; on the persistence of 
 the frontal suture in man, 44; on the proportion of the sexes in silk- 
 moths, 282, 284; secondary sexual characters of spiders, 307. 
 
 Canfield, Dr., on the horns of the Antilocapra, 265. 
 
 Canine teeth in man, 45; diminution of, in man, 60; diminution of, 
 in horses, 60; disappearance of, in male ruurnants, 60; large in the 
 early progenitors of man, 182. 
 
 Canines and horns, inverse development of, 586. 
 
 Canoes, use of, 54, 205. 
 
 Canthans, difference of color in the sexes of a species of, 333. 
 
 Cantharm lineatus, 386. 
 
 Capercailzie, polygamous, 248; proportion of the sexes in the, 280; 
 pugnacity of the male, 412; pairing of the, 416; autumn meetings of 
 the, 420; call of the, 425; duration of the courtship of, 460; behaviour 
 of the female, 476; inconvenience of black color to the female, 505; 
 sexual difference in the coloration of the, 559; crimson eyecere of the 
 male, 559. 
 
 Capitonidae, colors and nidification of the, 518. 
 
 Capra mgagrus, 579; crest of the male, 606; sexual difference in 
 the color of, 612. 
 
 Capreolus Sihiricus subecaudatus, 619. 
 
 Caprice, common to man and animals, 105. 
 
 Caprimulgus, noise made by the males of some species of, with 
 their wings, 426; Caprimulgus nrginianus, pairing of, 416. 
 
 Carabidas, 343. 
 
 Carbonnier, on the natural history of the pike, 281 ; on the rela- 
 tive size of the sexes in fishes, 380; courtship of Chinese Macropus, 
 
 Carcineutes, sexual difference of color hi, 520. 
 
 Carcinus m&nas, 303, 304. 
 
 Cardinalis mrginianus, 255. 
 
 Carduelis elegans, sexual differences of the beak in, 408. 
 
 Carnivora, marine, polygamous habits of, 247 ; sexual differences 
 in the colors of, 610. 
 
 Carp, numerical proportion of the sexes in the, 282. 
 
 Carr, R., on the peewit, 414. 
 
 Carrier pigeon, late development of the wattle in the, 269. 
 
 Carrion beetles, stridulation of, 342. 
 
 Carrion-hawk, bright colored female of, 546. 
 
 Carus, Prof. V. , on the development of the horns in merino sheep. 
 266; on antlers of red deer, 581. 
 
 Cassowary, sexes and incubation of the, 544. 
 
 Castnia, mode of holding wings, 357. 
 
 Castoreum, 604. 
 
 Castration, effects of, 577. 
 
 Casua/riwi galeatus, 544. 
 
 Cat, convoluted body in the extremity of a tail of a, 26; sick, sym- 
 pathy of a dog with a, 116.
 
 730 INDEX. 
 
 Cataract in Cebus Azara, 7. 
 
 Catarrh, liability of Cebus Azarce to, 7. 
 
 Catarridne monkeys, 174. 
 
 Caterpillars, bright colors of, 868. 
 
 Cathartes aura, 473; cathartes jota, love-gestures of the male, 432, 
 
 Catlin, G., correlation of color and texture of hair in the Mandans, 
 225; on the development of the beard among North American In- 
 dians, 639; on the great length of the hair in some North American 
 tribes, 662. 
 
 Caton, J. D. , on the development of the horns in Cenus mrginia- 
 nus and strongyloceros, 265; on the wild turkey, 525; on the pres- 
 ence of traces of horns in the female wapiti, 575*; on the fighting of 
 deer, 582; on the crest of the male wapiti, 606; on the colors of the 
 Virginian deer, 611; on sexual differences of color in the wapiti, 612; 
 on the spots of the Viginian deer, 624. 
 
 Cats, dreaming, 84; tortoise-shell, 260, 262, 269; enticed by val- 
 erian, 605; colors of, 620. 
 
 Cattle, rapid increase of, in South America, 53; domestic, lighter in 
 winter in Siberia, 260; horns of, 266, 576; domestic, sexual differ- 
 ences of, late developed, 269, numerical proportion of the sexes in, 
 279. 
 
 Caudal vertebrae, number of, in macaques and baboons, 65; basal 
 of monkeys, imbedded in the body, 66. 
 
 Cavolini, observations on Serranus, 184. 
 
 Cebus, maternal affection in a, 79; gradation of species of, 199; 
 cebus apella, 233; cebus azarce, liability of, to the same diseases as 
 man, 7 ; distinct sounds produced by 95 ; early maturity of the 
 female, 636; cebus capucinus, polygamous, 245; sexual differences of 
 color in, 613; hair on the head of, 627; cebus vetterosus, hair on the 
 head of, 627. 
 
 Cecidomyiidae, proportions of the sexes in, 286. 
 
 Celibacy, unknown among the savages of South Africa and South 
 America, 678. 
 
 Centipedes, 310. 
 
 Cephalopoda, absence of secondary sexual characters in, 297. 
 
 Cephalopterus ornatus, 423; cephalopterus penduliger, 424. 
 
 Cerambyx heros, stridulant organ of, 343. 
 
 Ceratodus, paddle of, 42. 
 
 Ceratophora aspera, nasal appendages of, 403 ; ceratophora stod. 
 dartii, nasal horn of, 403. 
 
 Cerceris, habits of, 330. 
 
 Cercocebus cethiops, whiskers, etc. , of, 629. 
 
 Cercopithecus, young, seized by an eagle and rescued by the troop, 
 115; definition of species of, 199; cercopithecus cephus, sexual differ- 
 ence of color in, 614, 630; cercopithecus cynosurus and griseo-viridis, 
 color of the scrotum in, 614; cercopithecus Diana, sexual differences 
 of color in, 614, 630; cercopithecus griseo-viridis, 114; cercopithecus 
 petaurista, whiskers, etc., of, 627. 
 
 Ceres, of birds, bright colors of, 559. 
 
 Ceriornis Temminckii, swelling of the wattles of the male during 
 courtship, 434. 
 
 Cervulus, weapons of, 586; cervulus moschatus, rudimentary horns 
 of the female, 574.
 
 INDEX. 731 
 
 Germs (dees, 265; cervus campestris, odor of, 604; cervus canadensis, 
 traces of horns in the female, 574; attacking a man, 582; sexual dif- 
 ference in the color of, 612; cervus elaphus, battles of male, 571; 
 horns of, with numerous points, 581; long hairs on the throat of, 
 595; cervus eldi, 265. 
 
 Cervus mantchuricus, 623 ; cervus paludosus, colors of, 613 ; 
 cervus strongyloceros, 265 ; cervus virginianus, 265 ; horns of, in 
 course of modification, 584. 
 
 Ceryle, male black-belted in some species of, 520. 
 
 Cetacea, nakedness of, 63. 
 
 Ceylon, frequent absence of beard in the natives of, 638. 
 
 Chaffinch, proportion of the sexes in the, 280; courtship of the, 456. 
 
 Chaffinches, 419; new mates found by, 464. 
 
 Clialcophaps indicus, characters of young, 529. 
 
 Chalcosoma atlas, sexual differences of, 334. 
 
 Cham&leo, sexual differences in the genus, 403; combats of, 405; 
 bifarcus, 403, 404; Owenii, 404; pumilus, 405. 
 
 Chamaspetes unicolor, modified wing-feather in the male, 428. 
 
 Chameleons, 402. 
 
 Chamois, danger-signals of, 114; transfer of male characters to an 
 old female, 574. 
 
 Champneys, Mr., acromio-basilar muscle and quadrupedal gait, 47. 
 
 Chapman, Dr., on stridulation in Scolytus, 342. 
 
 Chapuis, Dr. , on the transmission of sexual peculiarites in pigeons, 
 261; on streaked Belgian pigeons, 269, 507. 
 
 Char, male, coloring of, during the breeding season, 386. 
 
 Characters, male, developed in females, 257; secondary sexual, 
 transmitted through both sexes, 257; natural, artificial, exaggeration 
 of, by man, 664. 
 
 Charadrius Maticula, and pluvialis sexes and young of, 553. 
 
 Chardiu on the Persians, 669. 
 
 Charms, worn by women, 659. 
 
 Charruas, freedom of divorce arnomg the, 682. 
 
 Chasmorhynchus, difference of color in the sexes of, 441; colors 
 of, 560; \chft8morhynchus niveus, 441; chasmorhynchus nudicollis, 441; 
 cJiasmorhynchus tricarunculatus, 441. 
 
 Chastity, early estimation of, 134. 
 
 Chatterers, sexual differences in, 248. 
 
 Cheever, Rev. H. T., census of the Sandwich Islands, 290. 
 
 Cheiropetra, absence of secondary sexual characters in, 247. 
 
 Chelae of Crustacea, 301, 307. 
 
 Cfielonia, sexual differences in, 397.' 
 
 Chenalopex cegyptiacus, wing-knobs of, 414. 
 
 Cheraprogne, 445, 476. 
 
 Chest, proportions of, in soldiers and sailors, 37; large, of the 
 Quechua and Aymara Indians, 38. 
 
 Chevrotains, canine teeth of, 586. 
 
 Chiasognathus, stridulation of, 346; chiasognathus grantii, mand- 
 ibles of, 340. 
 
 Children, legitimate and illegitimate, proportion of the sexes 
 in, 276. 
 
 Chiloe, lice of the natives of, 193; population of, 197. 
 
 Chimwra monstrosa, bony process on the head of the male, 386.
 
 732 INDEX. 
 
 Chimseroid fishes, prehensile organs of male, 375. 
 
 Chimpanzee, 640; ears of the, 16; representatives of the eyebrows 
 in the, 21; hands of the, 56; absence of mastoid processes in the, 59; 
 platforms built by the, 75; cracking nuts with a stone, 91; direction 
 of the hair on the arms of the, 172; supposed evolution of the, 202; 
 polygamous and social habits of the, 674. 
 
 China, North, idea of female beauty in, 659; China, Southern, in- 
 habitants of, 224. 
 
 Chinese, use of flint tools by the, 164; difficulty of distinguishing 
 the races of the, 190; color of the beard in, 637; general beardless- 
 ness of the, 639; opinions of the, on the appearance of Europeans and 
 Cingalese, 659; compression of the feet of, 665. 
 
 Chinsurdi, his opinion of beards, 657, 663. 
 
 CJdamydera maculata, 433. 
 
 CMoeon, pedunculated eyes of the male of, 311. 
 
 CMoephaga, coloration of the sexes in, 524. 
 
 Chlorocoelus tanana (figured), 323. 
 
 Chorda dorsalis, 183. 
 
 Chough, red beak of the, 559. 
 
 Chromidae, frontal protuberance in male, 385; sexual differences in 
 color of, 392. 
 
 Chrysemys pieta, long claws of the male, 397. 
 
 C hrysococcyx, characters of young of, 529. 
 
 Chrysomelidae, stridulation of, 342. 
 ; Cicada pruinosa, 320; cicada geptendecim, 319. 
 
 Cicadae, songs of the, 319; rudimentary sound-organs in females of, 
 326. 
 
 Cicatrix of a burn, causing modification of the facial bones, 62. 
 
 Cichla, frontal protuberance of male, 385. 
 
 Cirnetiere du Sud, Paris, 24. 
 
 Cincloramphus cruralis, large size of male, 411. 
 
 Cinclus aquaticus, 518. 
 
 Cingalese, Chinese opinion of the appearance of the, 659. 
 
 Cirripedes, complemental males of, 235. 
 
 Civilization, effects of, upon natural selection, 151; influence of, in 
 the competition of nations, 208. 
 
 Clanging of geese, etc., 418. 
 
 Claparede, E., on natural selection applied to man, 55. 
 
 Clarke, on the marriage-customs of Kalmucks, 683. 
 
 Classification, 168. 
 
 Claus, C., on the sexes of Saphirina, 306. 
 
 Cleft-palate, inherited, 40. 
 
 Climacteris erythrops, sexes of, 546. 
 
 Climate, 35; cool, favorable to human progress, 150; power of 
 supporting extremes of, by man, 207; want of connection of, with 
 color, 219; direct action of, on colors of birds, 480. 
 
 Cloaca, existence of a, in the early progenitors of man, 182. 
 
 Cloacal passage existing in the human embryo, 10. 
 
 Clubs, used as weapons before dispersion of mankind, 204. 
 
 Clucking of fowls, 417. 
 
 Clythra 4-punctata, stridulation of, 342. 
 
 Coan, Mr., Sandwich Islanders, 213. 
 
 Cobbe, Miss, on morality in hypothetical bee- community, 113.
 
 INDEX. 733 
 
 Cobra, ingenuity of a, 399. 
 
 Coccus, 167. 
 
 Coccyx, 25; in the human embryo, 10; convoluted body at the 
 extremity of the, 25; imbedded in the body, 66. 
 
 Cochin-China, notions of beauty of the inhabitants of, 659, 661. 
 
 Cock, blind, fed by its companion, 116; game, killing a kite, 412; 
 comb and wattles of the, 457; preference shown by the, for the 
 young hens, 477; game, transparent zone in the hackles of a, 489. 
 
 Cock of the rock, 460. 
 
 Cockatoos, 559, 560, 562; nestling, 467; black, immature plumage 
 of, 582. 
 
 Ccelenterata, absence of secondary sexual characters in, 494. 
 
 Coffee, fondness of monkeys for, 7. 
 
 Cold, supposed effects of, 35; power of supporting, by man, 207. 
 
 Coloptera, 333; stridulation of, 322; stridulant organs of. discussed, 
 344. 
 
 Colias edusa and Jiynle, 361. 
 
 Collingwood, C., on the pugnacity of the butterflies of Borneo, 348; 
 on butterflies being attracted by a dead specimen of the same 
 species, 360. 
 
 Colobus, absence of the thumb, 57. 
 
 Colombia, flattened heads of savages of, 655. 
 
 Colonists, success of the English as, 160. 
 
 Coloration, protective, in birds, 556. 
 
 Color, supposed to be dependent on light and heat, 36; correlation 
 of, with immunity from certain poisons and parasites, 220; purpose 
 of, in lepidoptera, 359; relation of, to sexual functions in fishes, 388; 
 difference of, in the sexes of snakes, 398; sexual differences of, in 
 lizards, 405; influence of, in the pairing of birds of different species, 
 472; relation of, to nidification, 515, 519; sexual differences of, in 
 mammals, 609, 616; recognition of, by quadrupeds, 617; of children, 
 in different races of man, 635; of the skin in man, 690. 
 
 Colors, admired alike by man and animals, 104; bright, due to 
 sexual selection, 295; bright, among the lower animals, 295, .296; 
 bright, protective to butterflies and moths, 354; bright, in male 
 fishes, 380, 385; transmission of, in birds, 509. 
 
 Colquhoun, example of reasoning in a retriever, 88. 
 
 Columba passerina, young of, 532. 
 
 Colymb-us glacialis, anomalous young of, 550. 
 
 Comb, development of, in fowls, 270. 
 
 Combs and wattles in male birds, 457. 
 
 Community, preservation of variations useful to the, by natural 
 selection, 70. 
 
 Complexion, different in men and women, in an African tribe. 634, 
 
 Compositse, gradation of species among the, 199. 
 
 Comte, C., on the expression of the ideal of beauty by sculpture, 
 663. 
 
 Conditions of life, action of changed, upon man, 34; influence of, 
 on plumage of birds, 538. 
 
 Condor, eyes and comb of the, 484. 
 
 Conjugations, origin of, 103. 
 
 Conscience, 110, 131, 143; absence of, in some criminals, 131. 
 
 Constitution, difference of, in different races of men, 191.
 
 734 INDEX. 
 
 Consumption, liability of Cebus Azarce to, 7; connection betweep 
 complexion and, 221. 
 
 Convergence of characters, 201. 
 
 Cooing of pigeons and doves, 425. 
 
 Cook, Capt. , on the nobles of the Sandwich Islands, 669. 
 
 Cope, E. D., on the Dinosauria, 180. 
 
 Cophotis ceylanica, sexual differences of, 402, 405. 
 
 Copris, 336; copris isidis, sexual differences of, 335; copris lunaris, 
 stridulation of, 343. 
 
 Corals, bright colors of, 295. 
 
 Coral-snakes, 400. 
 
 Cordylus, sexual difference of color in a species of, 405. 
 
 Corfu, habits of the chaffinch in, 281. 
 
 Cornelius, on the proportion of the sexes in Lucanus Cervtis, 286. 
 
 Corpora Wolifina, 183; agreement of, with the kidneys of fishes, 10. 
 
 Correlated variation, 49. '.. 
 
 Correlation, influence of, in the production of races, 225.** / * 
 
 Corse, on the mode of fighting of the elephant, <685. 
 
 Corvus corone, 463. ; Cormis graculus, red beak of, 559 ; Corvus 
 pica, nuptial assembly of, 461. 
 
 Corydalis cornutus, large jaws of the male, 312. 
 
 Cosmetornis, 457, 526. 
 
 Cosmetornis vexillarius, elongation of wing-feathers in, 436, 457. 
 
 Cotingidae, sexual differences in, 248; coloration of the sexes of, 
 523; resemblance of the females of distinct species of, 535. 
 
 Coitus scorpius, sexual differences in, 382. 
 
 Coulter, Dr., on the Californian Indians, 291. 
 
 Counting, origin of, 163; limited power of, in primeval man, 205. 
 
 Courage, variability of, in the same species, 78; universal high 
 appreciation of, 139; importance of, 147; characteristic of men, 644. 
 
 Courtship, greater eagerness of males in, 250; of fishes, 376, 386; 
 of birds, 417, 426, 460. 
 
 Cow, winter change of color, 619. 
 
 Crab, devil, 304; crab, shore, habits of, 303. 
 
 Crabro cribra/rius, dilated tibiae of the male, 313. 
 
 Crabs, proportions of the sexes in, 288. 
 
 Cranz, on the inheritance of dexterity in seal-catching, 37. 
 
 Crawfurd, on the number of species of man, 199. 
 
 Crenilabrus massa and C. melops, nests, built by, 391. 
 
 Crest, origin of, in Polish fowls, 261. 
 
 Crests, of birds, difference of, in the sexes, 533; dorsal hairy, of 
 mammals, 606. 
 
 Cricket, field, stridulation of the, 320, 321; pugnacity of male, 327; 
 cricket, house, stridulations of the, 321. 
 
 Crickets, sexual differences in, 328. 
 
 Crinoids, complexity of, 103. 
 
 Crioceridse, stridulation of the, 342. 
 
 Croaking of frogs, 397. 
 
 Crocodiles, musky odor of, during the breeding season, 398. 
 
 Crocodilia, 398. 
 
 Crossbills, characters of young, 529. 
 
 Crosses in man, 196. 
 
 Crossing of races, effects of the, 218.
 
 INDEX. 735 
 
 CrossoptUon auritum, 454, 514, 538; adornment of both sexes of, 
 267; sexes alike in, 524. 
 
 Crotch, GK R., on the stridulation of beetles, 342, 345, on the 
 stridulation of Heliopathes, 345; on the stridulation of Acalles, 346; 
 habit of female deer at breeding time, 574. 
 
 Crow Indians, long hair of the, 662; young of the, 549. 
 
 Crows, 559; vocal organs of the, 421: living in triplets, 465; crows, 
 carrion, new mates found by, 463; crows, Indian, feeding their blind 
 companions, 116. 
 
 Cruelty of savages to animals, 133. 
 
 Crustacea, parasitic, loss of limbs by female, 235; prehensible feet 
 and antennae of, 237; male, more active than female, 250; partheno- 
 genesis in, 287; secondary sexual characters of, 299; amphipod, males 
 sexually mature while young, 552; auditory hairs of, 648. 
 
 Crystal worn in the lower lip by some Central African women, 656. 
 
 Cuckoo fowls, 270. 
 
 Culicidse, 235, 318; attracted by each other's humming, 318. 
 
 Cullen, Dr. , on the throat-pouch of the male bustard, 423. 
 
 Cultivation of plants, probable origin of, 151. 
 
 Cupples, Mr., on tbe numerical proportion of the sexes in dogs, 
 sheep and cattle, 279; on tbe Scotch deerhound, 589; on sexual 
 preference in dogs, 597. 
 
 Curculionidae, sexual difference in length of snout in some, 236; 
 hornlike processes in male, 338; musical, 341, 342. 
 
 Curiosity manifestations of, by animals, 80. 
 
 Curlews, double moult in, 442. 
 
 Cursores, comparative absence of sexual differences among the, 248. 
 
 Curtis, J., on the proportion of the sexes in Athalia, 286. 
 
 Cuvier, P., on the recognition of women by male quadrumana, 9; 
 Cuvier, Q., on the number of caudal vertebrae in the mandril, 65; on 
 instinct and intelligence, 75; views of, as to the position of man, 170; 
 on the position of the seals, 170; on Hectocotyle, 297. 
 
 Cyanalcyon, sexual difference in colors of, 520; immature plumage 
 of, 532. ' 
 
 Cyanecula suecica, sexual differences of, 537. 
 
 Cychrus, sounds produced by, 345. 
 
 Cycnia mendica, sexual difference of, in color, 358. 
 
 Cygnus ferus, trachea of, 424; cygnus immutdbilis, 550; cygnus 
 olor, white young of, 550. 
 
 Cyllo Leda, instability of the ocellated spots of, 486. 
 
 Cynanthus , variation in the genus, 481. 
 
 Cynipidae, proportion of the sexes in, 286. 
 
 Cynocephalus, difference of the young from the adult, 9; male 
 recognition of women by, 9; polygamous babits of species of, 246; 
 cynocephalus babouin, 710; cynocephalus chacma, 79; cynocephalus 
 gelada, 92; cynocephalus hamadryas, 92, 674; sexual difference of 
 color in, 614, 710; cynocephalus leucophus, colors of the sexes of, 
 614, 710; cynocephalus mormon, colors of the male, 614, 710 ; Cyno- 
 cephalus porcarius, mane of tbe male, 594; cynocephalus sphinx, 710. 
 
 (Jynopithecus niger, ear of, 18. 
 
 Cypridina, proportions of the sexes in, 287. 
 
 Cyprinidae, proportion of the sexes in the, 282; cyprinidae, Indian,
 
 736 INDEX. 
 
 Cyprinodontidaj, sexual differences in the, 380, 382. 
 
 Cyprinus auratus, 388. 
 
 Cypris, relations of the sexes in, 287. 
 
 Cyrtodactylus rubidus, 402. 
 
 Cystophora cristata, hood of, 603. 
 
 Dacelo, sexual difference of color in, 520; daeelo gaudichaudi, 
 young male of, 532. 
 
 Dal-ripa, a kind of ptarmigan, 280. 
 
 Damcdis albifrons, peculiar markings of, 621 ; damalis pygarga, 
 peculiar markings of, 621. 
 
 Dampness of climate, supposed influence of, on the color of the 
 skin, 35, 220. 
 
 Danaidse, 350. 
 
 Dances of birds, 431. 
 
 Dancing, universality of, 203. 
 
 Danger signals of animal, 114. 
 
 Daniell, Dr., his experience of residence in West Africa, 222. 
 
 Darfur, protuberances artificially produced by natives of, 655. 
 
 Darwin, F., on the stridulatio^ of Dermestes murinus, 342. 
 
 Dasychira pudibunda, sexual difference of color in, 358. 
 
 Davis, A. H., on the pugnacity of the male stag-beetle, 339; Davis, 
 J. B., on the capacity of the skull in various races of men, 60; on 
 the beards of the Polynesians, 639. 
 
 Death's Head Sphinx, 349. 
 
 Death-rate higher in towns than in rural districts, 157. 
 
 Death-tick, 347. 
 
 De Candolle, Alph., on a case of inherited power of moving the 
 scalp, 14. 
 
 Declensions, origin of, 103. 
 
 Decoration in birds, 434. 
 
 Decticus, 323. 
 
 Deer, 265; development of the horns in, 265; spots of young, 529, 
 624; horns of, 573, 578; use of horns of, 582, 590; horns of a, in 
 course of modification, 584; size of the horns of. 587; female, pair- 
 ing with one male, while others are fighting for her, 595; male, 
 attracted by the voice of the female, 600; male, odor emitted by 605; 
 Axis, sexual difference in the color of the, 612; fallow, different 
 colored herds of, 617; Mantchurian, 623; Virginian, 624; color of 
 the, not affected by castration, 611; colors of, 612. 
 
 Deerhound, Scotch, greater size of the male, 269, 589. 
 
 Defensive orders of mammals, 590. 
 
 De Qeer, C. , on a female spider destroying a male, 808. 
 
 De Kay, Dr.. on the bladder-nose seal, 603. 
 
 Delorenzi, U., division of malar bone, 44. 
 
 Demerara, yellow fever in, 221. 
 
 Dendrocygna, 529. 
 
 Dendrophiln fnintalis, young of , 555. 
 
 Denison, Sir W., manner of ridding themselves of vermin among 
 the Australians, 64; extinction of Tasmanians, 209. 
 
 Denny, H., on the lice of domestic animals, 193. 
 
 Dermestes murinus, stridulation of, 342. 
 
 Descent tracod through the mother alone, 672. 
 
 Deserts, protective coloring of animals inhabiting, 557.
 
 INDEX. 737 
 
 Desmarest, on the absence of suborbital pits in Antilope subyuttu- 
 rosa, 605; on the whiskers of Macacus, 607; on the color of the 
 opossum, 609; on the colors of the sexes of Mus minutus, 610; on 
 the coloring of the ocelot, 610; on the colors of seals, 610; on Anti- 
 lope caama, 612; on the colors of goats, 613; on sexual difference of 
 color in Ateles marginatus, 613; on the mandrill, 614; on Macacus 
 cynomolgus, 636. 
 
 Deemoulins, on the number of species of man, 199; on the musk- 
 deer, 605. 
 
 Desor, on the imitation of man by monkeys, 82. 
 
 Despine, P., on criminals destitute of conscious, 131. 
 
 Development, embryonic, of man, 9, 10, 12; correlated, 484. 
 
 Devil, not believed in by the Fuegians, 107. 
 
 Devil-crab, 304. 
 
 Devonian, fossil insect from the, 327. 
 
 Dewlaps, of cattle and antelopes, 608. 
 
 Diadema, sexual differences of coloring in the species of, 350. 
 
 Diamond-beetles, bright colors of, 333. 
 
 Diastema, occurrence of, in man, 46. 
 
 Diastylidae, proportion of the sexes in, 287. 
 
 Dicrurus, racket-shaped feathers in, 438 ; nidification of, 516; 
 dicrurus macrocercus, change of plumage in, 524. 
 
 DidelpMs opossum, sexual difference in the color of, 609. 
 
 Differences, comparative, between different species of birds of the 
 same sex, 536. 
 
 Digits, supernumerary, more frequent in men than in women, 
 253 ; supernumerary, inheritance of, 262 ; supernumerary, early 
 development of, 268. 
 
 Dimorphism in females of water-beetles, 313; in Neurothemis and 
 Agnon, 329. 
 
 Dipdorus, on the absence of beard in the natives of Ceylon, 638. 
 
 Dipelicus Cantori, sexual differences of, 335. 
 
 Diplopoda, prehensile limbs of the male, 310. 
 
 Dipsas cynodon, sexual difference in the color of, 398. 
 
 Diptera, 317. 
 
 Disease, generated by the contact of distinct peoples, 208, 
 
 Diseases, common to man and the lower animals, 7; difference of 
 liability to, in different races of men, 191; new, effects of, upon 
 savages, 208; sexually limited, 268. 
 
 Display, coloration of Lepidoptera for, 356; of plumage by male 
 birds, 447, 456. 
 
 Distribution, wide, of man, 54 ; geographical, as evidence of 
 specific distinctness in man, 192. 
 
 Disuse, effects of, in producing rudimentary organs, 13; and use 
 of parts, effects of, 36; of parts, influence of, on the races of men, 
 224. 
 
 Divorce, freedom of, among the Charruas, 682. 
 
 Dixon, E. S. on the pairing of different species of geese, 471; on 
 the courtship of peafowl, 477. 
 
 Dobrizhoffer, on the marriage customs of the Abipones, 684. 
 
 Dobson, Dr., on the Cheiroptera, 247; scent-glands of bats, 604; 
 frugivorous bats, 610. 
 
 Dogs, suffering from tertian ague, 8; memory of, 83; dreaming,
 
 738 INDEX. 
 
 84; diverging when drawing sledges over thin ice, 85; exercise of 
 reasoning faculties by, 88; domestic, progress of, in moral qualities, 
 90; distinct tones uttered by, 95; parallelism between his affection 
 for his master and religious feeling, 108 ; sociability of the, 113; 
 sympathy of, with a sick cat, 116; sympathy of, with his master, 
 116 ; their possession of conscience, 117; possible use of the hair 
 on the fore legs of the, 172; races of the, 201; numerical proportion 
 of male and female births in, 278; sexual affection between individ- 
 uals of, 215; howling at certain notes, 649; rolling in carrion, 606. 
 
 Dolichocephalic structure, possible cause of, 63. 
 
 Dolphins, nakedness of, 63. 
 
 Domestic animals, races of, 201 ; change of breeds of, 680. 
 
 Domestication, influence of, in removing the sterility of hybrids, 
 196. 
 
 D'Orbigny, A., on the influence of dampness and dryness on the 
 color of the" skin, 220; on the Yuracaras, 661. 
 
 Dotterel, 544. 
 
 Doubleday, E., on sexual differences in the wings of butterflies, 
 314; H., on" the porportion of the sexes in the smaller moths, 284; 
 males of Lasiocampa quercus and on the attraction of the Saturnia 
 carpini by the female, 284 ; on the proportion of the sexes in the 
 Lepidoptera, 284; on the ticking of Andbium tesselatum, 347; on the 
 structure of Ageronia feronia, 349; on white butterflies alighting 
 upon paper, 359. 
 
 Douglas, J. W-, on the sexual differences of the Hemiptera, 318; 
 colors of British Homoptera, 318. 
 
 Down, of birds, 442. 
 
 Draco, gular appendages of, 402. 
 
 Dragonet, Gernnieous, 381. 
 
 Dragon-flies, caudal appendages of male, 313 ; relative size of the 
 sexes of, 316; difference in the sexes of, 328; want of pugnacity by 
 the male, 330. 
 
 Drake, breeding plumage of the, 446. 
 
 Dreams, 84; possible source of the belief in spiritual agencies, 107. 
 
 Drill, sexual difference of color in the, 614. 
 
 Dromceus irroratus, 545. 
 
 Dromolcaa, Saharan species of, 519. 
 
 Drongo shrike, 524. 
 
 Drongos, racket-shaped feathers in the tails of, 436, 445. 
 
 Dryness of climate, supposed influence of, on the color of the 
 skin, 220. 
 
 Dryopithecus, 177. 
 
 Duck, harlequin, age of mature plumage in the, 552; breeding in 
 immature plumage, 552: long-tailed, preference of male, for certain 
 females, 478; pintail, pairing with a widgeon, 471; voice of the, 42o; 
 pairing with a shield-drake, 471 ; immature plumage of the, 532; 
 wild, sexual differences in the, 248; speculum and male characters of, 
 267; pairing with a pintail drake, 471. 
 
 Ducks, wild, becoming polygamous under partial domestication 
 249; dogs and cats recognized by, 468. 
 
 Dufosse, Dr., sounds produced by fish, 393. 
 
 Dugong, nakedness of, 63; tusks of, 572. 
 
 Dujardin, on the relative size of the cerebral ganglia in insects, 61.
 
 INDEX. 739 
 
 Duncan, Dr., on the fertility of early marriages, 156, comparative 
 health of married and single, 159. 
 
 Dupont, M., on the occurrence of the supra-condyloid foramen in 
 the humerus of man, 24. 
 
 Durand, J. P., on causes of variation, 34. 
 
 Dureau de la Malle, on the songs of birds, 97; on the acquisition 
 of an air by blackbirds, 421. 
 
 Dutch, retention of their color by the, in South Africa, 219. 
 
 Duty, sense of 110. 
 
 Duvaucel, female Hylobates washing her young, 79. 
 
 Dyaks, pride of, in mere homicide, 182. 
 
 Dynastes, large size of males of, 316. 
 
 Dynastini, stridulation of, 344. 
 
 Dytiscus, dimorphism of females of, 318; grooved elytra of tto 
 female, 313. 
 
 Eagle, young Cercopithecus rescued shell, by the troop, 115; oer- 
 copithecus, white-headed, breeding in immature plumage, 552. 
 
 Eagles, golden, new mates found by, 463. 
 
 Ear, motion of the, 15; external form of the, useless in man, 15; 
 rudimentary point of the, in man, 16. 
 
 Ears, more variable in men than women, 253; piercing and orna- 
 mentation of the, 656. 
 
 Earwigs, parental feeling in, 120. 
 
 Echidna, 178. 
 
 Echini, bright colors of some, 295. 
 
 Echinodermata, absence of secondary sexual characters in, 294. 
 
 Echis carinata, 400. 
 
 Ecker, figure of the human embryo, 11; on the development of the 
 gyri and sulci of the brain, 232; on the sexual differences in the 
 pelvis in man, 635; on the presence of a sagittal crest in Australians, 
 
 Edentata, former wide range of, in America, 193; absence of secon- 
 dary sexual characters in, 246. 
 
 Edolius, racket- shaped feathers in, 436. 
 
 Edwards, Mr., on the proportion of the sexes in North American 
 species of Papilio, 283. 
 
 Eels, hernmphroditism of, 184. 
 
 Egerton, Sir P., on the use of the antlers of deer, 581, 582; on the 
 pairing of red deer, 595; on the bellowing of stags, 601. 
 
 Eggs, hatched by male fishes, 391. 
 
 Egret, Indian, sexes and young of, 553. 
 
 Egrets, breeding plumage of, 442; white, 560. 
 
 Ehrenberg, on the mane of the male Hamadryas baboon, 594. 
 
 Ekstrom, M., on Hare Ida glacialis, 478. 
 
 Elachista rufocinerea, habits of male, 284. 
 
 Eland, development of the horns of the, 265. 
 
 Elands, sexual differences of color in, 611. 
 
 Elaphomyia, sexual differences in, 317. 
 
 Elaphrus uliginosus, stridulation of, 343. 
 
 Maps, 400. 
 
 Elateridae, proportion of the sexes in, 286. 
 
 Elaters, luminous, 315. 
 
 Elephant, 178; rate of increase of the, 53; nakedness of the, 63;
 
 740 INDEX. 
 
 using a fan, 91; Indian, forbearance to his keeper, 117; polygamous 
 habits of the, 246; pugnacity of the male, 571; tusks of, 572, 573, 
 578, 587; Indian, mode of fighting, of the, 585; male, odor emitted 
 by the, 604; attacking white or grey horses, 617. 
 
 Elevation of abode, modifying influence of, 39. 
 
 Elimination of inferior individuals, 155. 
 
 Elk, 579; winter change of the, 619; Irish, horns of the, 587. 
 
 Ellice Islands, beards of the natives, 639, 663. 
 
 Elliot, D. G., on Pelecanus erytJirorhynchus, 442; R.,on the nu. 
 merical proportion of the sexes in young rats, 279; on the proportion 
 of the sexes in sheep, 278; Sir W. on the polygamous habits of the 
 Indian wild boar, 246. 
 
 Ellis, on the prevalence of infanticide in Polynesia, 676. 
 
 Elphinstone, Mr., on local difference of stature among the Hindoes, 
 35; on the difficulty of distinguishing the native races of India, 190. 
 
 Elytra, of the females of Dytiscus, Acilias.Hydroporus, 313. 
 
 Emberiza, characters of young, 529; Emberiza miliaria, 529; 
 Emberiza scJice-niclu^, 468; head- feathers of the male, 455. 
 
 Embryo of man, 10, 11; of the dog, 11. 
 
 Embryos of mammals, resemblance of the, 28. 
 
 Emigration, 155. 
 
 Emotions experienced by the lower animals in common with man, 
 77; manifested by animals, 80. 
 
 Emperor butterfly, 348. 
 
 Emperor moth, 358. 
 
 Emu, sexes and incubation of, 545. 
 
 Emulation of singing birds, 419. 
 
 Endurance, estimation of, 134. 
 
 Energy, a characteristic of men, 645. 
 
 England, numerical proportion of male and female births in, 274. 
 
 Engleheart, Mr. , on the finding of new mates by starlings, 464. 
 
 English, loiccess of, as colonists, 160. 
 
 Engravers, short-sighted, 37. 
 
 Entomostraca, 304. 
 
 Entozoa, difference of color between the males and females of 
 some, 294. 
 
 Environment, direct action of the, in causing differences between 
 the sexes, 254. 
 
 Envy, persistence of, 127. 
 
 Eocene period, possible divergence of men during the, 177. 
 
 Eolidae, colors of, produced by the biliary glands, 296. 
 
 Epeira nigra, small size of the male of, 308. 
 
 Ephemerae, 311. 
 
 Ephemeridse, 328. 
 
 Ephippiger vitium, stridulating organs of, 322, 326. 
 
 Epicalia, sexual differences of coloring in the species of, 350. 
 
 Equus hemionus, winter change of, 619. 
 
 Erateina, coloration of, 357. 
 
 Ercolani, Prof., hermaphroditism in eels, 184. 
 
 Erect attitude of man, 57, 58. 
 
 Eristalis, courting of 318. 
 
 Eschricht, on the development of hair in man, 20; on a lanuginous 
 mustache in a female fetus, 21; on the want of definition between
 
 INDEX. 741 
 
 the scalp and the forehead in some children, 171; on the arrange- 
 ment of the hair in the human fetus, 172; on the hairyness of the 
 face in the human fetus of both sexes, 688, 689. 
 
 Esmerdlda, difference of color in the sexes of, 334. 
 
 Esox Imius, 281 ; esox reticulatus, 386. 
 
 Esquimaux, 72, 150; their belief in the inheritance of dexterity in 
 seal -catching, 37; mode of life of, 224. 
 
 Estrelda amandava, pugnacity of the male, 415. 
 
 Eubagis, sexual differences of coloring in the species of, 351. 
 
 Euchirus longimanus, sound produced by, 344. 
 
 Eudromias morinellus, 544. 
 
 Eulampis jugularis, colors of the female, 516. 
 
 Euler, on the rate of increase in the U. S., 50. 
 
 Eumomota super ciHaris, racket-shaped feathers in the tail of, 486. 
 
 Eupetomena macroura, colors of the female, 516. 
 
 Euphema splendida, 521. 
 
 Euplocamus erythrophthalmus, possession of spurs by the female, 
 413. 
 
 Europe, ancient inhabitants of, 206. 
 
 Europeans, difference of, from Hindoos, 218; hairyness of, proba- 
 bly due to reversion, 687. 
 
 Eurostopodus, sexes of, 546. 
 
 Eurygnathus, different proportions of the head in the sexes of, 
 314. 
 
 Eustephanus, sexual differences of species of, 408; young of, 555. 
 
 Exaggeration of natural characters by man, 664. 
 
 Exogamy, 673, 675. 
 
 Experience, acquisition of, by animals, 90. 
 
 Expression, resemblances in, between man and the apes, 171. 
 
 Extinction of races, causes of, 206. 
 
 Eye, destruction of the, 36; change of position in, 62; obliquity 
 of, regarded as a beauty by the Chinese and Japanese, 659. 
 
 Eyebrows, elevation of, 14; development of long hairs in, 20; in 
 monkeys, 171; eradicated in parts of South America and Africa, 656; 
 eradication of, by the Indians of Paraguay, 662. 
 
 Eyelashes, eradication of, by the Indians of Paraguay, 662. 
 
 Eyelids, colored black, in part of Africa, 655. 
 
 Eyes, pillared, of the male of Chloeon, 311; difference in the color 
 of, in the sexes of birds, 483. 
 
 Eyton, T. C., observations on the development of the horns in the 
 fallow deer, 265. 
 
 Eyzies, Les, human remains from, 207. 
 
 Fabre, M., on the habits of Cerceris, 330. 
 
 Facial bones, causes of modification of the, 62. 
 
 Faculties, diversity of, in the same race of men, 80; inheritance 
 of, 31; diversity of, in animals of the same species, 31; mental varia- 
 tion of, in the same species, 74; of birds, 466. 
 
 Fakirs, Indian, tortures undergone by, 134. 
 
 Falco leucoceplialus, 552; falco peregnnus, 463, 524; falco tinnun- 
 tulus, 463. 
 
 Falcon, peregrine, new mate found by, 463. 
 
 Falconer, H., on the mode of fighting of the Indian elephant, 585; 
 W canines in a female deer, 586; on Hyomoschus aquaticus, 624.
 
 742 INDEX. 
 
 Falkland Islands, horses of, 206. 
 
 Fallow-deer, different colored herds of, 617. 
 
 Famines, frequency of, among savages, 51. 
 
 Farr, Dr., on the effects of profligacy, 155; on the influence of 
 marriage on mortality, 157, 158. 
 
 Farrar, F. W., on the origin of language, 98; on the crossing or 
 blending of languages, 102; on the absence of the idea of God in 
 certain races of men, 105; on early marriages of the poor, 156; on 
 the middle ages, 160. 
 
 Farre, Dr. , on the structure of the uterus, 43. 
 
 Fashions, long prevalence of, among savages, 658, 666. 
 
 Faye, Prof., on the numerical proportion of male and female births 
 in Norway and Russia, 275; on the greater mortality of male children 
 at and before birth, 275. 
 
 Feathers, modified, producing sounds, 427 et seq., 512; elongated, 
 in male birds, 435, 457; racket-shaped, 436; barbless and with fila- 
 mentous barbs in certain birds, 437; shedding of margins of, 446. 
 
 Feeding, high, probable influence of, in the pairing of birds of 
 different species, 472. 
 
 Feet, thickening of the skin on the soles of the, 37; modification 
 of, in man, 58. 
 
 Felis ccmadensis, throat-ruff of, 594; felis pardalis and F. mitis, 
 sexual difference in the coloring of, 610. 
 
 Female, behavior of the, during courtship, 178; birds, differences 
 of, 536. 
 
 Females, presence of rudimentary male organs in, 184; preference 
 of, for certain males, 242; pursuit of, by males, 250; occurrence of 
 secondary sexual characters in, 255; development of male character 
 by, 257. 
 
 Females and males, comparative numbers of, 241, 244; compar- 
 ative mortality of, while young, 244. 
 
 Femur and tibia, proportions of, in the Aymara Indians, 39, 
 
 Fenton, Mr., decrease of Maories, 210 ; infanticide among the 
 Maories, 289. 
 
 Ferguson, Mr., on the courtship of fowls, 474. 
 
 Fertilization, phenomena of, in plants, 251; in the lower animals, 
 251. 
 
 Fertility lessened under changed conditions, 214. 
 
 Fevers, immunity of negroes and rnulattoes from, 220. 
 
 Piber zibethicus, protective coloring of it, 619. 
 
 Fick, H., effect of conscription for military service, 152. 
 
 Fidelity, in the elephant, 117; of savages to one another, 133; 
 importance of, 141. 
 
 Field slaves, difference of, from house slaves, 224. 
 
 Fiji Archipelago, population of the, 198; Fiji Islands, beards of 
 the natives, 639, 663; marriage customs of the, 683. 
 
 Fijians, burying their old and sick parents alive, 116; estimation 
 of the beard among the, 663; admiration of, for a broad occiput, 665. 
 
 Filial affection, partly the result of natural selection, 119. 
 
 Filum terminate, 25. 
 
 Finch, racket-shaped feathers in the tail of a, 436. 
 
 Finches, spring change of color in, 447; British, females of the, 596. 
 
 Fingers, partially coherent, in species of Hylobatet, 57.
 
 INDEX. 743 
 
 Finlayson, on the Cochin Chinese, 659 
 
 Fire, use of, 54, 164, 204. 
 
 Fischer, on the pugnacity of the male of, Lethrus cephalotes, 340. 
 
 Fischer, F. Von, on display of brightly colored parts by monkeys 
 in courtship, 709. 
 
 Fish, eagerness of male, 250; proportion of the sexes in, 281; 
 sounds produced by, 393. 
 
 Fishes, kidneys of, represented by Corpora Wolffiana in the human 
 embryo, 10; male hatching ova in their mouths, 185; receptacles for 
 ^ova possessed by, 235; relative size of the sexes in, 380; fresh water, 
 *of the tropics, 389; protective resemblance in, 390; change of color 
 in, 390; nest-building, 391; spawning of, 392; sounds produced by, 
 393, 640; continued growth of, 552. 
 
 Flamingo, age of mature plumage, 551. 
 
 Flexor pollicis longus, similar variation of, in man, 48. 
 
 Flies, humming of, 318. 
 
 Flint tools, 164. 
 
 Flints, difficulty of chipping into form, 56. 
 
 Florida, Quiscalvs major in, 281. 
 
 Florisuga mettivora, 504. 
 
 Flounder, coloration of the, 390. 
 
 Flower, W. H ., on the abductor of the fifth metatarsal in apes, 
 47; on the position of the seals, 170; on the Pithecia monachus, 229; 
 on the throat-pouch of the male bustard, 423. 
 
 Fly-catchers, colors and nidification of, 518. 
 
 Fetus, human, woolly covering of the, 21; arrangement of the 
 hair on, 172. 
 
 Food, influence of, upon stature, 35. 
 
 Foot, prehensile power of the, retained in some savages, 58; pre- 
 hensile, in the early progenitors of man, 182. 
 
 Foramen, supra-condyloid, exceptional occurrence of in the 
 humerus of man, 24, 49; in the early progenitors of man, 179. 
 
 Forbes, D., on the Aymara Indians, 39; on local variation of color 
 in the Quichuas, 223; on the hairlessness of the Aymaras and 
 Quichuas, 639; on the long hair of the Aymaras and Quichuas, 637, 
 662. 
 
 Forel, F., on white young swans, 550. 
 
 Forester, Hon. O. W., on an orphan hawk, 465. 
 r Formica rufa, size of the cerebral ganglia in, 61. 
 
 Fossils, absence of, connecting man with the apes, 178. 
 
 Fowl, occurrence of spurs in the female, 257; game, early pugnac- 
 ity of, 270; Polish, early development of cranial peculiarities of, 270; 
 variations in plumage of, 438; examples of correlated development in 
 the, 484; domestic, breeds and sub -breeds of, 523. 
 
 Fowls, spangled Hamburg, 259, 270; inheritance of changes of plu- 
 mage by, 269, sexual peculiarities in, transmitted only to the same 
 sex, 260, loss of secondary sexual characters by male, 261 ; Polish, 
 origin of the crest in, 261; period of inheritance* of characters by, 269; 
 cuckoo, 270; development of the comb in, 270; numerical proportion 
 of the sexes in 280 ; courtship of, 473 ; mongrel, between a black 
 Spanish cock and different hens, 485, penciled Hamburg, difference 
 of the sexes in, 509, Spanish, sexual differences of the comb in, 509; 
 spurred, in both sexes, 511
 
 744 INDEX. 
 
 Fox, W. D., on some half -tamed wild ducks becoming polygamous 
 and on polygamy in the guinea-fowl and canary-bird, 249 ; on the 
 proportion of the sexes in cattle, 280 ; on the pugnacity of the pea- 
 cock, 413; on a nuptial assembly of magpies, 461 ; on the finding of 
 new mates by crows, 463; on partridges living in triplets, 465; on the 
 pairing of a goose with a Chinese gander, 471. 
 
 Foxes, wariness of young, in hunting districts, 90; black, 616. 
 
 Fraser, C., on the * different colors of the sexes in a species of 
 Squdla, 306, Fraser, G., colors of Thecla, 353. 
 
 Frere, Hookhain, quoting Theognis on selection in mankind, 33. 
 
 Fringitta canabina, 447; fringitta ciris, age of mature plumage in, 
 551; fnngitta cyanea, age of mature plumage in, 551 ; fringitta 
 leucophrys, young of, 553; fringitta spinns, 472; fringitta tristis, 
 change of color in, in spring, 446; young of, 553. 
 
 Fringillidae, resemblance of the females of distinct species of, 535. 
 
 Frog, bright colored and distasteful to birds, 396. 
 
 Frogs, 395; male, temporary receptacles for ova possessed by, 235; 
 ready to breed before the females, 240; fighiug of, 396; vocal organs 
 of, 397. 
 
 Frontal bone, persistance of the suture in, 44. 
 
 Fruits, poisonous, avoided by animals, 75. 
 
 Fuegians, 150, 163; difference of stature among the, 35; power of 
 sight in the, 38; skill of, in stone-throwing, 55; resistance of the, 
 to their severe climate, 71, 207; mental capacity of the, 73; quasi- 
 religious sentiments of the, 107; resemblance of, in mental charac 
 ters, to Europeans, 203; mode of life of the, 224; aversion of, to hair 
 on the face, 662; said to admire European women, 664. 
 
 Fulgoridae, songs of the, 319. 
 
 Fur, whiteness of, in arctic animals in winter, 260. 
 
 Fur-bearing animals, acquired sagacity of, 90. 
 
 Qatticrex, sexual difference in the color of the irides in, 483; galli- 
 crex cnstatus, pugnacity of male, 409; red caruncle occurring in the 
 male during the breeding-season, 442. 
 
 Gallinacese, frequency of polygamous habits and of sexual differ- 
 ences in the, 248, love- gestures of, 432; decomposed feathers in, 437; 
 stripes of young, 529; comparative sexual differences between the 
 species of, 536, plumage of, 537. 
 
 Gallinaceous birds, weapons of the male, 412; racket-shaped feath- 
 ers on the heads of, 436. 
 
 Oallinula cMorpus, pugnacity of the male, 409. 
 
 Galloperdix, spurs of, 413; development of spurs in the female, 
 512. 
 
 Qallophasis, young of, 533. 
 
 Galls. 68. 
 
 Oattus bankiva, neck -hackles of, 445; gattus stanleyi, pugnacity of 
 the male, 412. 
 
 Galton, Mr., on hereditary genius, 31; gregariousness and inde- 
 pendence in animals, 118; on the struggle between the social and 
 personal impulses, 141; on the effects of natural selection on civilized 
 nations, 151; on the sterility of sole daughters, 153; on the degree 
 of fertility of people of genius, 154; on the early marriages of the 
 poor, 156; on the ancient Greeks, 150; on the Middle Ages, 160; on 
 the progress of the U. S., 161; on S. African notions of beauty, 661.
 
 INDEX. 745 
 
 Gammarus, use of the chelae of, 303; gammarus marinus, 305. 
 
 Gannets, white only when mature, 560. 
 
 Ganoid fishes, 180, 187. 
 
 Gaour, horns of the, 576. 
 
 Gap between man and the apes, 177. 
 
 Gaper, sexes and young of, 553. 
 
 Gardner, on an example of rationality in a Gelasimus, 305. 
 
 Garrulus glandarius, 463. 
 
 Gartner, on sterility of hybrid plants, 196. 
 
 Gasteropoda, 297; pulmoniferous, courtship of, 297. 
 
 Oasterosteus, 249; nidification of, 391; gasterosteus leiurus, 376, 
 886, 391 ; gasterosteus trachurus, 376. 
 
 GastropJiora, wings of, brightly colored beneath, 357. 
 
 Gauchos, want of humanity among the, 139. 
 
 Gaudry, M., on a fossil monkey, 175. 
 
 Gavia, seasonal change of plumage in, 561. 
 
 Geese, clanging noise made by, 418; pairing of different species of, 
 471; Canada, selection of mates by, 471, 473. 
 
 Gegenbaur, C., on the number of digits in the Ichthyopterygia, 
 42; on the hermaphroditisui of the remote progenitors of the verte- 
 brata, 183; two types of nipple in mammals, 184. 
 
 Gela&imus, proportions of the sexes in a species of, 288; use of the 
 enlarged chelae of the male, 303; pugnacity of males of, 305; 
 rational actions of a, 305; difference of color in the sexes of a species 
 of, 307. 
 
 Gemmules, dormant in one sex, 261. 
 
 Genius, 31; hereditary, 643, 644; fertility of men and women of, 
 154. 
 
 Geoffroy-Saint-Hilaire, Isid., on the recognition of women by male 
 quadrumaiia, 9 ; on monstrosities, 33 ; coincidences of arrested 
 development with polydactylism, 42; on animal-like anomalies in the 
 human structure, 45; on the correlation of monstrosities, 49; on the 
 distribution of hair in man and monkeys, 64; on the caudal vertebrae 
 of monkeys, 65; on correlated variability, 68; on the classification of 
 man, 167; on the long hair on the heads of species of Semnopithecus, 
 171; on the hair in monkeys, 172; on the development of horns in 
 female deer, 574; and F. Cuvier, on the mandrill, 614; on Hylobates, 
 636, 637 
 
 Geographical distribution, as evidence of specific distinctions in 
 man, 192. 
 
 Geometrae, brightly colored beneath, 357. 
 
 Geophagus, frontal protuberance of male, 385, 392; eggs hatched 
 by the male, in the mouth or branchial cavity, 392. 
 
 Georgia, change of color in Germans settled in, 223. 
 
 Geotrvpes, stridulation of, 343, 345. 
 
 Gerbe, M., on the nest-building of Crenilabus massa and C. melon* 
 891. 
 
 Gerland, Dr., on the prevalence of infanticide, 132, 659, 676; on 
 the extinction of races, 207. 
 
 Gervais, P., on the hairiness of the gorilla, 64; on the mandrill, 
 614. 
 
 Gesture-language, 203. 
 
 Ghost-moth, sexual difference of color in the, 358.
 
 746 INDEX. 
 
 Giard, M., disputes descent of vertebrates from Ascidians, 182; 
 color of sponges and Ascidians, 295; musky odor of Sphinx, 349. 
 
 Gibbon, voice of, 602, 647. 
 
 Gibbon, Hoolock, nose of, 171. 
 
 Gibbs, Sir D., on differences of the voice in different races of men, 
 646. 
 
 Gill, Dr., male seals larger than females, 247; sexual differences 
 in seals, 588. 
 
 Giraffe, its mode of using the horns, 580; mute, except in the rut- 
 ting season, 600. 
 
 Giraud-Teulon, on the cause of short sight, 38. 
 
 Glanders, communicable to man from the lower animals, 7. 
 
 Glands, odoriferous, in mammals, 604, 605. 
 
 Glareola, double moult in, 442. 
 
 Olomeris limbata, difference of color in the sexes of, 310. 
 
 Glow-worm, female apterous, 235; luminosity of the, 314. 
 
 Gnants, dances of, 318; auditory powers of, 648. 
 
 Gnu, skeletons of, found locked together, 571 ; sexual differences 
 in the color of the, 612. 
 
 Goat, male, wild, falling on his horns, 579; male, odor, emittted 
 by, 604; male, wild crest of the, 608; Berbura, mane, dewlap, etc., 
 of the male, 608; Kemas, sexual difference in the color of the, 612. 
 
 Goats, sexual differences in the horns of, 260; horns of, 266; mode 
 of fighting of, 579; domestic, sexual differences of, late developed, 
 269; beards of, 606. 
 
 Goatsucker, Virginian, pairing of the, 416. 
 
 Gobies, nidification of, 391. 
 
 God, want of the idea of, in some races of men, 105. 
 
 Godron M., on variability, 33; on difference of stature, 35; on the 
 want of connection between climate and the color of the skin, 219; 
 on the color of the skin, 225; on the color of infants. 636. 
 
 Goldfinch, 421, 446; proportion of the sexes in the, 281; sexual 
 differences of the beak in the, 409; courtship of the, 455; North 
 American, young of, 553. 
 
 Goldfish, 388, 389. 
 
 Gomphus, proportions of the sexes in, 287; difference in the sexes 
 of, 328. 
 
 Oonepteryx Rhamni, 354, sexual difference of color in, 365. 
 
 Goodsir, Prof., on the affinity of the lancelet to the ascidians, 181. 
 
 Goosander, young of, 532. 
 
 Goose, Antarctic, colors of the, 560; Canada, pairing with a Ber- 
 nicle gander, 471; Chinese, knob on the beak of the, 484; Egyptian, 
 414; Sebastopol, plumage of, 438; snow, whiteness of the, 561; spur- 
 winged, 414. 
 
 Gorilla, 640; semi-erect attitude of the, 58; mastoid processes of 
 the, 59; protecting himself from the rain with his hands, 172; manner 
 of sitting, 172; supposed to be a kind of mandrill, 202; polygamy of 
 the, 245, 647, 675; voice of the, 602; cranium of, 636; fighting of 
 male, 641. 
 
 Gosse, P. H., on the pugnacity of the male humming-bird, 409; 
 Gosse, M., on the inheritance of artificial modifications of the skull, 
 689. 
 
 Gould, B. A., on variation in the length of the legs in man, 29;
 
 INDEX. 747 
 
 measurements of American soldiers, 34, 36; on the proportions of 
 the body and capacity of the lungs in different races of men, 190; on 
 the inferior vitality of mulattoes, 195; Q-ould, J., on migration of 
 swifts, 122; on the arrival of male snipes before the females, 240; 
 on the numerical proportion of the sexes in birds, 280; on Neomorpha 
 Grypus, 408; on the species of Eustephanus, 408; on the Australian 
 musk-duck, 468; on the relative size of the sexes in Briziura lobata 
 and Cindoramphus cruralis, 411; on Lobivanellus Idbatus, 414; on 
 the habits of Menura Alberti, 421; on the rarity of song in brilliant 
 birds, 421; on Selasphorus platycercus, 429; on the bower-birds, 432, 
 461; on the ornamental plumage of the humming-birds, 440; on the 
 moulting of the ptarmigan, 444; on the display of plumage by the 
 male humming-birds, 447; on the shyness of adorned male birds, 456; 
 on the decoration of the bowers of bower- birds, 469; on the decora- 
 tion of their nests by humming-birds, 469; on variation in the genus 
 Cynanthus, 481; on the color of the thighs in a male paroquet, 481; 
 on Vrosticte Benjamini, 502 et seq.; on the nidification of the Orioles, 
 516; on obscurely colored birds building concealed nests, 516; on 
 trogons and kingfishers, 520; on Australian parrots, 521; on Austral- 
 ian pigeons, 522; on the moulting of the ptarmigan, 526; on the im- 
 mature plumage of birds, 530 et seq.; on the Australian species of 
 Turnix, 542; on the young of Althurus polytmus, 555; on the colors 
 of the bills of toucans, 560; on the relative size of the sexes in the 
 marsupials of Australia, 588; on the colors of the marsupials, 609. 
 
 Goureaux, on the stridulation of Mutilla europcea, 332. 
 
 Gout, sexually transmitted, 268. 
 
 Graba, on the Pied Ravens of the Feroe Islands, 482; variety of 
 the Guillemot, 482. 
 
 Gradation of secondary sexual characters in birds, 488. 
 
 Grallatores, absence of secondary sexual characters in, 248; 
 double moult in some, 443. 
 
 Grallina, nidification of, 517. 
 
 Grasshoppers, stridulation of the, 324. 
 
 Gratiolet, Prof., on the anthropomorphous apes, 175; on the evolu- 
 tion of the anthropomorphous apes, 202; on the difference in the de- 
 velopment of the brains of apes and man, 231. 
 
 Gray, Asa, on the gradation of species among the Composites, 199; 
 Gray, J. E., on the caudal vertebrae of monkeys, 65; on the presence 
 of rudiments of horns in the female of Cervulus moschatus, 574; on 
 the horns of goats and sheep, 575; on crests of male antelopes, 606; 
 on the beard of the ibex, 607; on the Berbura goat, 608; on sexual 
 differences in the coloration of rodents, 609; ornaments of male sloth, 
 610; on the colors of the Elands, 611; on the sing-sing antelope, 612; 
 on the colors of goats, 612; on Lemur Macaco, 618; on the hog-deer, 
 623. 
 
 " Greatest happiness principle," 135, 136. 
 
 Greeks, ancient, 159. 
 
 Green, A. H,, on beavers fighting, 570; on the voice of the 
 beaver, 602. 
 
 Greenfinch, selected by a female canary, 472. 
 
 Greg, W. R., on the effects of natural selection on civilized nations, 
 151; on the early marriages of the poor, 156; on the ancisa* Greeks, 
 159. -
 
 748 INDEX. 
 
 Grenadiers, Prussian, 32. 
 
 Greyhounds, numerical proportion of the sexes in, 244; numerical 
 proportion of male and female births in, 278, 291. 
 
 Grouse, red, monogamous, 248; pugnacity of young male, 414; pro- 
 ducing a sound by beating their wings together, 416; duration of 
 courtship of, 460; colors and nidification of, 518. 
 
 Gruber, Dr., on the occurrence of the supra-condyloid foramen in 
 the humerus of man, 23; on division of malar bone,' 44; stridulation 
 of locust, 322; ephippiger, 326. 
 
 Grus Americanus, age of mature plumage in, 551; breeding in im- 
 mature plumage, 552; grits virgo, trachea of, 425. 
 
 Oryllus campestris, 321; pugnacity of male, 327; gryttus domes- 
 ticus, 322 
 
 Grypus, sexual differences in the beak in, 408. 
 
 Guanacoes, battles of, 570; canine teeth of, 580. 
 
 Guanas, strife for women among the, 641; polyandry among the 
 677. 
 
 Guanche skeletons, occurrence of the supra-condyloid foramen in 
 the humerus of, 24. 
 
 Guaranys, proportion of men and women among, 276; color of 
 new-born children of the, 636; beards of the, 639. 
 
 Guenee, A., on the sexes of Ilyperythra, 283. 
 
 Guilding, L., on the stridulation of the locustidae, 320. 
 
 Guillemot, variety of the, 482. 
 
 Guinea, sheep of, with males only horned, 266. 
 
 Guinea-fowl, monogamous, 248; occasional polygamy of the, 249; 
 markings of the, 488. 
 
 Guinea-pigs, inheritance of the effects of operations by, 67. 
 
 Gulls, seasonal change of plumage in, 560; white, 560. 
 
 Giinther, Dr., on paddle of Ceratodus, 42; on herrnaphroditisrn in 
 Serranus, 184; on male fishes hatching ova in their mouths, 185, 
 391; on mistaking infertile female fishes for males, 281; on the pre- 
 hensile organs of male Plagiostomous fishes, 37; spines and brushes 
 on fishes, 37; on the pugnacity of the male salmon and trout, 377; 
 on the relative size of the sexes in fishes, 380; on sexual differences 
 in fishes, 381 ; et seq. ; on the genus (Jallionymus, 381 ; on a protec- 
 tive resemblance of pipe-fish, 390; on the genus of Solenostomn, 392; 
 on the coloration of frogs and toads, 396; combat of Test u do elegans, 
 398; on the sexual differences in the Ophidia, 399; on differences of 
 the sexes of lizards, 402 et seq. 
 
 Gynanisa Isis, ocellated spots of, 486. 
 
 Gypsies, uniformity of, in various parts of the world, 220. 
 
 Habits, bad, facilitated by familiarity, 139; variability of the force 
 of, 142. 
 
 Hackel, E., on the origin of man, 3; on rudimentary characters, 12; 
 on death caused by inflammation of the vermiform appendage, 23; on 
 the canine teeth in man, 45; on the steps by which man became a 
 biped, 58; on man as a member of the Catarrhine group, 176; on the 
 position of the Lemuridae, 178; on the genealogy of the Mammalia, 
 179; on the lancelet, 181; on the transparency of pelagic animals, 
 295; on the musical powers of women. 653. 
 
 Hagen, H., and Walsh, B. D., on American Nueroptera. 286. 
 
 Hair, development of, in man, 20; character of, supposed to b*
 
 INDEX. 749 
 
 determined by light and heat, 3G; distribution of, in man, 63, 685; 
 possibly removed for ornamental purposes, 65; arrangement and direc- 
 tion of, 171; of the early progenitors of man, 182; different texture 
 of, in distinct races, 190; and skin correlation of color of, 225; devel- 
 opment of, in mammals, 606 ; management of, among different 
 peoples, 655; great length of, in some North American tribes, 662; 
 elongation of the, on the human head, 689; possible inherited effect 
 of plucking out, 689. 
 
 Hairiness, difference of, in the sexes in man, 637; variation of, in 
 races of men, 637. 
 
 Hairs and excretory pores, numerical relation of, in sheep, 225. 
 
 Hairy family, Siamese, 687. 
 
 Halbertsma, Prof., hermaphroditism in Serranus, 184. 
 
 Hamadryas baboon, turning over stones, 114; mane of the male, 594. 
 
 Hamilton, C., on the cruelty of the Kaffirs to animals, 133; on the 
 engrossment of the women by the Kaffir chiefs, 680. 
 
 Hammering, difficulty of, 55. 
 
 Hancock, A., on the colors of nudibranch Mollusca, 296, 298. 
 
 Hands, larger at birth, in the children of laborers, 37; structure of, 
 in the quadrumaua, 56; arms, freedom of, indirectly correlated with 
 dimunition of canines, 60. 
 
 Handwriting, inherited, 100. 
 
 Handyside, Dr., supernumery mammae in men, 42. 
 
 Harcourt, E. Vernon, on Fringttla cannabina, 447. 
 
 Hare, protective coloring of the, 619. 
 
 Harelda glacialis, 478. 
 
 Hares, battles of male ? 570. 
 
 Harlan, Dr., on the difference between field and house-slaves, 224. 
 
 Harris, J. M., on the relation of complexion to climate, 222; Harris, 
 T. W., on the Katy-did locust, 321; on the stridulation of the grass- 
 hoppers, 324; on CEcanthus nivalis, 328; on the coloring of Lepi- 
 doptera, 356; on the coloring of Saturnia lo, 358. 
 . Harting, spur of the Ornithorhynchus, 573. 
 
 Hartman, Dr. , on the singing of Cicada septendecim, 319. 
 
 Hatred, persistence of, 127. 
 
 Haughton, S., on a variation of the flexor pollicis long us, in man, 48. 
 
 Hawks, feeding orphan nestling, 465. 
 
 Hayes, Dr., on the diverging of sledge-dogs on thin ice, 85. 
 
 Haymond, R., on the drumming of the male Tetrao umbellus, 426; 
 on the drumming of birds, 427. 
 
 Head, altered position of, to suit the erect attitude of man, 62; 
 hairiness of, in man, 64; processes of, in male beetles, 334; artificial 
 alterations of the form of the, 664. 
 
 Hearne, on strife for women among the North American Indians, 
 640; on the North American Indians' notion of beauty, 659; repeated 
 elopements of a North American woman, 682. 
 
 Heart, in the human embryo, 10. 
 
 Heat, supposed effects of, 36. 
 
 Eectocotyle, 298. 
 
 Hedge- war bier, 539; young of the, 548. 
 
 Heel, small projection of, in the Aymara Indians, 39. 
 
 Hegt, M., on the development of the spurs in peacocks, 267. 
 
 H^liconidse, 350; mimicry of, by other butterflys, 366.
 
 750 INDEX. 
 
 Heliopathes, stridulation peculiar to the male, 345. 
 
 Heliothrix auriculata, young of, 532, 533. 
 
 Helix pomatia, example of individual attachment in, 297. 
 
 Hellins, J., proportions of sexes of, Lepidoptera reared by, 285. 
 
 Hemholtz, on pleasure derived from harmonies, 104; on the human 
 eye, 501; on the vibration of the auditory hairs of Crustacea, 649; 
 the physiology of harmony, 649. 
 
 Hemiptera, 318. 
 
 Hemitragus, beardless in both sexes, 607. 
 
 Hemsbach, M. von, on medial mamma in man, 42. 
 
 Hen, clucking of, 418. 
 
 Hepburn, Mr., on the autumn song of the water-ouzel, 420. 
 
 Hepialus Jiumuli, sexual difference of color in the, 358. 
 
 Herbs, poisonous, avoided by animals, 75. 
 
 Hermaphroditisin, of embryos, 183; in fishes, 184. 
 
 Herodias bubulcus, vernal moult of, 445. 
 
 Heron, Sir R., on the habits of pea-fowl, 475, 477, 503. 
 
 Herons, love-gestures of, 331; decomposed feathers in, 437; breed- 
 ing plumage of, 443, 444; young of the, 548, 553; sometimes dimor- 
 phic, 552; continued growth of crest and plumes in the males of 
 some, 552; change of color in some, 562. 
 
 Hesperomys cognatus, 648. 
 
 Hetcerina, proportion of the sexes in, 287; difference in the sexes 
 of, 328. 
 
 Heterocerus, stridulation of, 342. 
 
 Hewitt, Mr., on a game-cock killing a kite, 412; on the recognition 
 of dogs and cats by ducks, 468; on the pairing of a wild duck with a 
 pintail drake, 471 ; on the courtship of fowls, 473; on the coupling 
 of pheasants with common hens, 477. 
 
 Hilgendorf , sounds produced by crustaceans, 309. 
 
 Hindoo, his horror of breaking his caste, 138, 140. 
 
 Hindoos, local differences of stature among, 35; difference of, from 
 Europeans, 218; color of the beard in, 637. 
 
 Hipparchia Janira,488; instability of the ocellated spots of, 486. 
 
 Hippocampus, development of, 185; marsupial receptacles of the 
 male, 392; Jiippocampus minor, 227, 230. 
 
 Hippopotamus, nakedness of, 63. 
 
 Hips, proportions of, in soldiers and sailors, 36. 
 
 Hodgson, S., on the sense of duty, 111. 
 
 Hoffberg, on the horns of the reindeer, 574; on sexual preferences 
 shown by reindeer, 598. 
 
 Hoffman, Prof., protective colors, 318; fighting of frogs, 396. 
 
 Hog, wart, 592; river, 593. 
 
 Hog-deer, 623. 
 
 Holland, Sir H. , on the effects of new diseases, 208. 
 
 Homologous structures, correlated variation of, 49. 
 
 Homoptera, 319; stridulation of the, and Orthoptera, discussed, 827. 
 
 Honduras, Quiscalus major in, 281. 
 
 Honey-buzzard of India, variation in the crest of, 481. 
 
 Honey-sucker, females and young of, 533. 
 
 Honey-suckers, moulting of the, 444; Australian, nidification of, 516. 
 
 Honor, law of, 137. 
 
 Hooker, Dr., forbearance of elephant to his keeper, 117; on the 
 color of the beard in man, 637 ,
 
 INDEX. 751 
 
 Hookham, Mr., on mental concepts in animals, 94. 
 
 Hoolock Gibbon, nose of, 171. 
 
 Hoopoe, 421; sounds produced by male, 427. 
 
 Hoplopterus armatus, wing-spurs of, 414. 
 
 Hornbill, African, inflation of the neck-wattle of the mtle during 
 courtship, 435. 
 
 Hornbills, sexual difference in the color of the eyes in, 483; nidfica- 
 tion and incubation of, 516. 
 
 Home, C., on the rejection of a brightly colored locust by lizards 
 and birds, 428. 
 
 Horns, sexual differences of, in sheep and goats, 260; loss of, in 
 female merino sheep, 261 ; development of, in deer, 264 ; devel- 
 opment in antelopes, 265; from the head and thorax, in male beetles, 
 336; of deer, 573, 577, 587; originally a masculine character in sheep, 
 576, and canine teeth, inversed development of, 586. 
 
 Horse, fossil, extinction ot the, in South America, 218; polygamous, 
 246; canine teeth of male, 572; winter change of color, 619. 
 
 Horses, rapid increase of, in South America, 53; diminution of 
 canine teeth in, 60 ; dreaming, 84 ; of the Falkland Islands and 
 Pampas, 206; numerical proportion of the sexes in, 244, 245; lighter 
 in winter in Siberia, 260; sexual preferences in, 598; pairing preferently 
 with those of the same color 617; numerical proportion of male and 
 female births in, 278; formerly striped, 626. 
 
 Hottentot women, peculiarities of, 198. 
 
 Hottentots, lice of, 192; readily become musicians, 650; notions of 
 female beauty of the, 660; compression of nose by, 665. 
 
 Hough, Dr. S. , men's temperature more variable than women's, 
 253, proportion of sexes in man, 274. 
 
 House-slaves, difference of, from field-slaves, 224. 
 
 Houzeau, on the baying of the dog, 84; on reason in dogs, 84; 
 birds killed by telegraph wires, 90; on the cries of domestic fowls 
 and parrots, 96, 99; animals feel no pity, 116; suicide in the Aleutian 
 islands, 133. 
 
 Howorth, H. H., extinction of savages, 209. 
 
 Huber, P., on ants playing together, 77; on memory in ants, 83; 
 on the intercommunication of ants, 101 ; on the recognition of each 
 other by ants after separation, 331. 
 
 Hue, on Chinese opinions of the appearance of Europeans, 659. 
 
 Huia, the, of New Zealand, 236. 
 
 Human, man classed alone in a, kingdom, 167; sacrifices, 108. 
 
 Humanity, unknown among some savages, 133; deficiency of, 
 among savages, 139. 
 
 Humboldt, A. von, on the rationality of mules, 88; on a parrot 
 preserving the language of a lost tribe, 206; on the cosmetic arts of 
 savages, 654; on the exaggeration of natural characters by man, 664; 
 on the red painting of American Indians, 665. 
 
 Hume, D., on sympathetic feelings, 123. 
 
 Humming-bird, racket-shaped feathers in the tail of a, 436; dis- 
 play of plumage by the male, 447. 
 
 Humming-birds, ornament their nests, 104, 469; polygamous, 248; 
 proportion of the sexes in, 281, 555; sexual differences in, 408, 503; 
 pugnacity of male, 409; modified primaries of male, 429; coloration 
 of the sexes of, 440; display by, 503; nidification of the, 516, 517; 
 colors of female, 516; young of, 555.
 
 752 INDEX. 
 
 Humor, sense of, in dogs, 80. 
 
 Humphreys, H. N., on the habits of the stickleback, 249, 376' 
 
 Hunger, instinct of, 127. 
 
 Huns, ancient, flattening of the nose by the, 665. 
 
 Hunter, J., on the number of species of man, 199; on secondary sexual 
 characters, 234; on the general behavior of female animals during 
 courtship, 251; on the muscles of the larynx in song-birds, 421; on 
 strength of males, 588; on the curled frontal hair of the bull, 606; on 
 the rejection of an ass by a female zebra, 617. 
 
 Hunter, \V. W., on the recent rapid increase of the Santali, 51; on 
 the Santali, 218. 
 
 Huss, Dr. Max, on the mammary glands, 184. 
 
 Hussey, Mr., on a partridge distinguishing persons, 468. 
 
 Hutchinson, Col., example of reasoning in a retriever, 88. 
 
 Hutton, Capt., on the male wild goat falling on his horns, 579. 
 
 Huxley, T. H., on the structural agreement of man with the apes, 
 2; on the agreement of the brain in man with that of lower animals, 
 6; on the adult age of the orang, 9; on the embryonic development 
 of man, 10; on the origin of man, 3, 12; on variation in the skulls of 
 the natives of Australia, 29, on the abductor of the fifth metatarsal in 
 apes, 47; on the nature of the reasoning power, 87; on the position 
 of man, 176; on the suborders of primates, 173; on the Lemuridae> 
 179; on the Dinosauria, 180; on the amphibian affinities of the Ich- 
 thyosaurians, 180; on variability of the skull in certain races of man, 
 198; on the races of man, 201; supplement on the brain, 227. 
 
 Hybrid birds, production of, 470. 
 
 Hydrophobia communicable between man and the lower animals, 7. 
 
 Hydroporus, dimorphism of females of, 313. 
 
 Hydaphus portinus, 623. 
 
 Hygrogonus, 392. 
 
 Hyla, singing species of, 397. 
 
 Hylobates, absence of the thumb in, 57; upright progression of 
 some species of, 59; maternal affection in a, 79; direction of the hair 
 on the arms of species of, 172; females of, less hairy below than 
 males, 637; hylobates agilis, 57; hair on the arms of, 172; musical 
 voice of, 602, superciliary ridge of, 636; voice of, 647. 
 
 Hylobates hoolock, sexual difference of color in, 613; hylobates lar, 
 57; hair on the arms of, 72; female less hairy, 637; hylobates leucis- 
 cus, 57; song of, 647; hylobates syndactylus, 57; laryngeal sac of, 602. 
 
 Hylophila prasinana, 349. 
 
 Hymenoptera, 330; large size of the cerebral ganglia in, 437; 
 classification of, 168; sexual differences in the wings of, 314; aculeate, 
 relative size of the sexes of, 316. 
 
 Hymenopteron, parasitic, with a sedentary male, 251. 
 
 Hyomoschus aquaticus, 624. 
 
 Hypcrythra, proportion of the sexes in, 283. 
 
 Hypogymna dispar, sexual difference of color in, 358. 
 
 Hypopyra, coloration of, 357. 
 
 Ibex, male, falling on his horns, 579; beard of the, 607. 
 
 Ibis, white, change of color of naked skin in, during the breeding 
 season, 442; scarlet, young of the, 548; ibis tantalus, age of mature 
 plumage in, 551; breeding in immature plumage, 552.
 
 INDEX. 753 
 
 Ibisis, decomposed feathers in, 437; white, 560; and black, 562. 
 
 Ichneumonidae, difference of the sexes in, 331. 
 
 Ichthyopterygia, 42. 
 
 Ichthyosaurians, 180. 
 
 Idiots, microcephalous, their characters and habits, 40; hairiness 
 and animal nature of their actions, 41; microcephalous imitative 
 faculties of, 98. 
 
 Iguana tuberculata, 402. 
 
 Iguanas, 402. 
 
 Illegitimate and legitimate children, proportion of the sexes in, 276. 
 
 Imagination, existence of, in animals, 84. 
 
 Imitation, 77; of man by monkeys, 82; tendency to, in monkeys, 
 microcephalous idiots and savages, 98; influence of, 146. 
 
 Immature plumage of birds, 528, 531. 
 
 Implacentata, 179. 
 
 Implements, employed by monkeys, 91; fashioning of, peculiar to 
 man, 92. 
 
 Impregnation, period of, influence of, upon sex, 277. 
 
 Improvement, progressive, man alone suppposed to be capable 
 of, 89. 
 
 Incisor teeth, knocked out or filed by some savages, 656. 
 
 Increase, rate of, 50; necessity of checks in, 53. 
 
 Indecency, hatred of, a modern virtue, 135. 
 
 India, difficulty of distinguishing the native races of, 190; 
 Cyprinidae of, 389; color of the beard in races of men of, 637. 
 
 Indian, North American, honored for scalping a man of another 
 tribe, 132. 
 
 Individuality, in animals, 93. 
 
 Indolence of man, when free from a struggle for existence, 161. 
 
 Indopicus carlotta, colors of the sexes of, 521. 
 
 Infanticide, prevalence of, 52, 132, 289, 290; supposed cause of, 658; 
 prevalence and causes of, 675 et seq. 
 
 Inferiority, supposed physical, of man, 72. 
 
 Inflammation of the bowels, occurrence of, in Cebus Azarce, 7. 
 
 Inheritance, 31; of long and short sight, 37; of effects of use of 
 vocal and mental organs, 100; of moral tendencies, 139, 143; laws of 
 257; sexual, 262; sexually limited, 506. 
 
 Inquisition, influence of the, 159. / " 
 
 Insanity, hereditary, 31. 
 
 Insect, fossil, from the Devonian, 327. 
 
 Insectivora, 610; absence of secondary sexual characters in, 247. 
 
 Insects, relative size of the cerebral ganglia in, 60; male, appear- 
 ance of, before the females, 240; pursuit of female, by the males, 250; 
 period of development of sexual characters in, 268 ; secondary 
 sexual characters of, 311; kept in cages, 319, 327; stridulation, 646. 
 
 Insessores, vocal organs of, 421. 
 
 Instep, depth of, in soldiers and sailors, 36. 
 
 Instinct and intelligence, 75; migratory, vanquishing the maternal, 
 122, 128. 
 
 Instinctive actions, the result of inheritance, 119; impulses, dif- 
 ference of the force, 125 et seq.; and moral impulses, alliance of, 126. 
 
 Instincts, 74; complex origin of, through natural selection, 76; 
 possible origin of some, 76; acquired, of domestic animals, 118;
 
 754 INDEX. 
 
 variability of the force of, 121; difference of force between the 
 social and other, 126, 143; utilized for new purposes, 651. 
 
 Instrumental music of birds, 425, 430. 
 
 Intellect, influence of, in natural selection in civilized society, 154. 
 
 Intellectual faculties, their influence on natural selection in man, 
 144; probably perfected through natural selection, 146. 
 
 Intelligence, Mr. H. Spencer on the dawn of, 75. 
 
 Intemperance, no reproach among savages, 135; its destructive 
 ness, 155. 
 
 Intoxication in monkeys, 7. 
 
 Iphias glaucippe, 354. 
 
 Iris, sexual difference in the color of the, in birds, 435, 483. 
 
 Ischio-pubic muscle, 46. 
 
 Ithaginis cruentas, number of spurs in, 413. 
 
 lulus, tarsal suckers of the males of, 310. 
 
 Jackals learning from dogs to bark, 82. 
 
 Jack-snipe, coloration of the, 557. 
 
 Jacquinot, on the number of species of man, 199. 
 
 Jaeger, Dr., length of bones increased from carrying weights, 36; 
 on the difficulty of approaching herds of wild animals, 114; male 
 silver pheasant, rejected when his plumage was spoiled, 476. 
 
 Jaguars, black, 616. 
 
 Janson, E. W., on the proportions of the sexes in Tomicus villosua, 
 286; on stridulant beetles, 342. 
 
 Japan, encouragement of licentiousness in, 52. 
 
 Japanese, general beardlessness of the, 639; aversion of the, to 
 whiskers, 662. 
 
 Jardine, Sir W., on the Argus pheasant, 436, 457. 
 
 Jarrold, Dr., on modifications of the skull induced by unnatural 
 position, 62. 
 
 Jarves, Mr., on infanticide in the Sandwich Islands, 290. 
 
 Javans, relative height of the sexes of, 638; notions of female 
 beauty, 661. 
 
 Jaw, influence of the muscles of the, upon the physiognomy of 
 the apes, 60. 
 
 Jaws, smaller proportionately to the extremities, 37; influence of 
 food upon the size of, 37; diminution of, in man, 60; in man, re- 
 duced by correlation, 641. 
 
 Jay, young of the, 548; Canada, young of the, 549. 
 
 Jays, new mates found by, 463; distinguishing persons, 468. 
 
 Jeffreys, J. Gwyn, on the form of the shell in the sexes of the 
 Gasteropoda, 297; on the influence of light upon the colors of shells, 
 298. 
 
 Jelly-fish, bright colors of some, 295. 
 
 Jenner, Dr., on the voice of the rook, 426; on the finding of new 
 mates by magpies, 462; on retardation of the generative functions in 
 birds, 465. 
 
 Jenyns, L., on the desertion of their young by swallows, 122; on 
 male birds singing after the proper season, 465. 
 
 Jerdon, Dr., on birds dreaming, 84; on the pugnacity of the male 
 bulbul, 409; on the pugnacity of the male Ortygornis gularis, 412; 
 on the spurs of Ocdloperdix, 413; on the habits of Lobivanellus, 414;
 
 INDEX. 755 
 
 on the spoonbill, 425; on the drumming of the Kali j -pheasant, 426; 
 on Indian bustards, 429; on Otis bengalensis, 432; on the ear-tufts of 
 Sypheotides auritus, 436; on the double moults of certain birds, 444; 
 on the moulting of the honeysuckers, 444; on the moulting of bustards, 
 plovers and drongos, 445; on the spring change of color in some 
 finches, 447; on display in male birds, 447; on the display of the 
 undertail coverts by the male bulbul, 456; on the Indian honey- 
 buzzard, 481; on sexual differences in the color of the eyes of horn- 
 bills, 483; on the markings of the Tragopan pheasant, 487; on the 
 nidification of the Orioles, 516; on the nidification of the hornbills, 
 517; on the Sultan yellow-tit, 521; on Palceornis javanicus, 525; on 
 the immature plumage of birds, 529, et seq.; on representative 
 species of birds, 533; on the habits of Turnix, 542; on the continued 
 increase of beauty of the peacock, 552; on coloration in the genus 
 Palceornis, 562. 
 
 Jevons, W. S., on the migrations of man, 53. 
 
 Jews, ancient use of flint tools by the, 164; uniformity of, in 
 various parts of the world, 220; numerical proportion of male and 
 female births among the, 275; ancient, tattooing practiced by, 655. 
 
 Johnstone, Lieut., on the Indian elephant, 246. 
 
 Jollofs, fine appearance of the, 670. 
 
 Jones, Albert, proportion of sexes of Lepidoptera, reared by, 285. 
 
 Juan Fernandez, humming-birds of, 555. 
 
 Junonia, sexual differences of coloring in species of, 851. 
 
 Jupiter, comparison with Assyrian effigies, 663. 
 
 Kaffir skull, occurrence of the diastema in a, 45. 
 
 Kaffirs, their cruelty to animals, 133; lice of the, 194; color of the, 
 661; engrossment of the handsomest women by the chiefs of the, 680; 
 marriage-customs of the, 683. 
 
 Kali j -pheasant, drumming of the male, 426; young of, 533. 
 
 Kallima, resemblance of, to a withered leaf, 353. 
 
 Kalmucks, general beardlessness of, 639; aversion of, to hairs on 
 the face, 662. 
 
 Kangaroo, great red, sexual difference in the color of, 609. 
 
 Kant, Imm., on duty,110; on self-restraint, 124; on the number of 
 species of man, 199. 
 
 Katy-did, stridulation of the, 321. 
 
 Keen, Dr., on the mental powers of snakes, 399. 
 
 Keller, Dr., on the difficulty of fashioning stone implements, 55. 
 
 Kent, W. S. , elongation of dorsal fin of Callionymus lyra, 382; 
 courtship of Labrus mixtus, 386; colors and courtship of Cantharus 
 lineatus, 386. 
 
 Kestrels, new mates found by, 463. 
 
 Kidney, one, doing double work in disease, 35. 
 
 King, W. R., on the vocal organs of Tetrao cupido, 423; on the 
 drumming of grouse, 427; on the reindeer, 574; on the attraction of 
 male deer by the voice of the female, 601. 
 
 King and Fitzroy, on the marriage customs of the Fuegians, 684. 
 
 King-crows, nidification of, 516. 
 
 Kingfisher, 421; racket-shaped feathers in the tail of a, 436. 
 
 King-fishers, colors and nidification of the, 518, 520, 522; imma- 
 ture plumage of the, 532, 533; young of the, 548. 
 
 King Lory, 521; immature plumage of the, 532.
 
 756 INDEX. 
 
 Kingsley, C., on the sounds produced by Umbrina, 394. 
 
 Kirby and Spence, on sexual differences in the length of the 
 snout in Curculionidse, 236; on the courtship of insects, 250; on the 
 elytra of Dytiscus, 313; on peculiarities in the legs of male insects, 
 the 
 
 313; on the relative size of the sexes in insects, 316; on the Fulgor- 
 idae, 319; on the habits of Termites, 830; on difference of color in the 
 sexes of beetles, 333; on the horns of the male lamellicorn beetles, 
 336; on hornlike processes in male Curculionidse, 339; on the pug- 
 nacity of the male stag-beetle, 339. 
 
 Kite, killed by a game-cock, 412. 
 
 Knot, retention of winter plumage by the, 444. 
 
 Knox, R., on the semilunar fold, 19; on the occurrence of the 
 supra-condyloid foramen in the humerus of man, 23; on the features 
 of the young Memnon, 192. 
 
 Koala, length of the coecum in, 22. 
 
 Kdbus ellipsiprymnus, proportion of the sexes in, 280. 
 
 Kolreuter, on the sterility of hybrid plants, 196. 
 
 Koodoo, development of the horns of the, 265; markings of the, 621. 
 
 KQppen, P. T., on the migratory locust, 320. 
 
 Koraks, marriage customs of, 683. 
 
 Kordofan, protuberances artificially produced by natives of, 655. 
 
 Ko'rte, on the proportion of sexes in locusts, 287; Russian locusts. 
 320. 
 
 Kovalevsky, A., on the affinity of the Ascidia to the Vertebrata, 181. 
 
 Kovalevsky, W., on the pugnacity of the male capercailzie, 412; 
 on the pairing of the capercailzie, 416. 
 
 Krause, on a convoluted body at the extremity of the tail in a 
 Macacus and a cat, 25. 
 
 Kupffer, Prof., on the affinity of the Ascidia to the Vertebrata, 181. 
 
 Labidocera Darwnii, prehensile organs of the male, 301. 
 
 Ldbrus, splendid colors of the species of, 382; labrus mixtus, sexual 
 c4fferences in, 382, 386; labrus pavo, 388. 
 
 Lacertilia, sexual differences of, 401. 
 
 Lafresnaye, M. de, on birds of paradise, 439. 
 
 Lamarck, on the origin of man, 3. 
 
 Lainellibranchiata, 296. - 
 
 Lamellicorn beetles, horn-like processes from the head and thorax 
 of, 334, 336; influence of sexual selection on, 341. 
 
 Lamellicornia, stridulation of, 343. 
 
 Lament, Mr., on the tusks of the walrus, 572; on the use of its 
 tusks by the walrus, 585; on the bladder-nose seal, 603. 
 
 Lampornls porphyrurus, colors of the female, 516. 
 
 Lampyrida?, distasteful to mammals, 314. 
 
 Lancelot, 181, 187. 
 
 Landois, H., gnats attracted by sound, 318; on the production of 
 sound by the Cicadae, 819; on the stridulating organ of the crickets, 
 821; on Decticus, 323; on the stridulating organs of the Acridiidse, 
 824; stridulating apparatus in Orthoptera, 326; on the stridulation of 
 yecrophorus, 342; on the stridulant organs of Ceramlyx heros, 343; 
 on the stridulant organ of Oeotrupcs, 343; on the stridulating organs 
 in the Ooleoptera, 344; on the ticking of Anobium, 347. 
 
 Landor, Dr., on remorse for not obeying tribal custom, 130. 
 
 Language, an art, 97; articulate, origin of, 98; relation of the
 
 INDEX. 757 
 
 progress of, to the development of the brain, 99; effects of inher- 
 itance in production of, 100; complex structure of, among barbar- 
 ous nations, 103; natural selection in, 103; gesture, 203; primeval, 
 204; of a lost tribe preserved by a parrot, 206. 
 
 Languages, presence of rudiments in, 102; classification of, 102; 
 variability of, 102; crossing or blending of, 102; complexity of, no test 
 of perfection or proof of special creation, 103; resemblance of, evi- 
 dence of community of origin, 169; languages and species, identity 
 of evidence of their gradual development, 102. 
 
 Lanius, 525; characters of young, 529; lanius rufus, anomalous 
 young of, 550. 
 
 Lankester, E. R., on comparative longevity, 151, 155; on the de- 
 structive effects of intemperance, 155. 
 
 Lanugo, of the human fetus, 21, 685. 
 
 Lapponian language, highly artificial, 103. 
 
 Lark, proportion of the sexes in the, 281 ; female, singing of the, 420. 
 
 Larks, attracted by a mirror, 469. 
 
 Lartet, E., comparison of cranial capacities of skulls of recent and 
 tertiary mammals, 62; on the size of the brain in mammals, 91; on 
 Dryopithecus, 177; on pre-historic flutes, 650. 
 
 Larus, seasonal change of plumage in, 561. 
 
 Larva, luminous, of a Brazilian beetle, 314. 
 
 Larnyx, muscles of the, in song birds, 421. 
 
 Lasiocampa quercus, attraction of males by the female, 284; sexual 
 difference of color in, 358. 
 
 Latham, R. G., on the migrations of man, 53. 
 
 Latooka, perforation of the lower lip by the women of, 656. 
 
 Laurillard, on the abnomal division of the malar bone in man, 44. 
 
 Lawrence, W., on the superiority of savages to Europeans in 
 power of sight, 38; on the color of negro infants, 636; on the fond- 
 ness of savages for ornaments, 654; on beardless races, 662; on the 
 beauty of the English aristocracy, 670. 
 
 Layard, E. L., on the instance of rationality in a cobra, 399; on 
 the pugnacity of Oallus Stanleyi, 412. 
 
 Laycock, Dr., on vital periodicity, 8; theroid nature of idiots, 41. 
 
 Leaves, autumn, tints, useless, 296. 
 
 Lecky, Mr., on the sense of duty, 111; on suicide, 132; on the 
 practice of celibacy, 135; his view of the crimes of savages, 135; on 
 the gradual rise of morality, 141. 
 
 Leconte, J. L., on the stridulant organ in the Coprini andDynas- 
 tini, 344. 
 
 Lee, H., on the numerical proportion of the sexes in the trout, 282. 
 
 Leg, calf of the, artifically modified, 655. 
 
 Legitimate and illegitimate children, proportion of the sexes in, 276. 
 
 Legs, variation of the length of the, in man, 29; proportions of, in 
 soldiers and sailors, 36; front, atrophied in some male butterflies, 
 314; peculiarities of, in male insects, 314. 
 
 Leguay, on the occurrence of the supra-condyloid foramen in the 
 hurnerus of man, 24. 
 
 "Lek "of the black cock and capercailzie, 460. 
 
 Lemoine, Albert, on the origin of language, 98. 
 
 Lemur macaco, sexual difference of color in, 613. 
 
 Lemuridse, 173; ears of the, 17; variability of the muscles in the, 
 46; position and derivation of the, 178; their origin, 188.
 
 758 INDEX. 
 
 Lemurs, uterus in the, 43. 
 
 Lenguas, disfigurement of the ears of the, 656. 
 
 Leopards, black, 616. 
 
 Lepidoptera, 348; numerical proportions of the sexes in the, 282j 
 coloring of, 349; ocellated spots of, 486. 
 
 Lepidosiren, 180, 187. 
 
 Leptalides, mimicry of, 368. 
 Leptorhynchus angustatus, pugnacity of male, 339. 
 
 Leptura testacea, difference of color in the sexes of, 333. 
 
 Leroy, on the wariness of young foxes in hunting districts, 90; on 
 the desertion of their young by swallows, 122. 
 
 Leslie, D., marriage customs of Kaffirs, 683. 
 
 Lesse, valley of the, 24. 
 
 Lesson, on the birds of paradise, 248, 457; on the sea-elephant, 603. 
 
 Lessona, M., observations on Serranus, 184. 
 
 Lethrus cepJicdotes, pugnacity of the males of, 337, 340. 
 
 Leuciscus phoxinus, 282. 
 
 Leuckart, R., on the vesicula prostatica, 26; on the influence of the 
 age of Barents on the sex of offspring, 277. 
 
 Levator clavicular, muscle, 47. 
 
 Libellula depressa, color of the male, 329. 
 
 LibellulidjE, relative size of the sexes of, 316; difference in the 
 sexes of, 329. 
 
 Lice of domestic animals and man, 193. 
 
 Licentiousness a check upon population, 52; prevalence of, among 
 savages, 134. 
 
 Lichenstein, on Chera progne, 476. 
 
 Life, inheritance at corresponding periods of, 259, 263. 
 
 Light, effects on complexion, 36; influence of, upon the colors of 
 shells, 298. 
 
 Lilford, Lord, the ruff attracted by bright objects, 469. 
 
 Limosa lapponica, 544. 
 
 Unai-ia, 525; linaria montana, 281. 
 
 Lindsay, Dr. W. L., diseases communicated from animals to man, 
 8; madness in animals, 89; the dog considers his master his God, 108. 
 
 Linnaeus, views of, as to the position of man, 170. 
 
 Linnet, numerical proportion of the sexes in the, 281; crimson 
 forehead and breast of the, 447; courtship of the, 455. 
 
 Lion, polygamous, 247; mane of the, defensive, 594; roaring of 
 the, 601. 
 
 Lions, stripes of young, 528. 
 
 Lips, piercing of the, by savages, 657. 
 
 Lithobius, prehensile appendages of the female, 310. 
 
 Lithosia, coloration in, 356. 
 
 Littorina littorea, 296. 
 
 Livingstone, Dr., manner of sitting of gorilla, 172; on the influence 
 of dampness and dryness on the color of the skin, 220; on the 
 liability of negroes to tropical fevers after residence in a cold climate, 
 220; on the spur-winged goose, 414; on weaver-birds, 427; on an 
 African night-jar, 436, 457; on the battle-scars of South African 
 male mammals, 570; on the removal of the upper incisors by tlit 
 Batokas, 656; on the perforation of the upper lip by the Makalolo, 
 657; on the Banyai, 661.
 
 INDEX. 759 
 
 Livonia, numerical proportion of male and female births in, 243, 
 275. 
 
 Lizards, relative size of the sexes of, 401 ; gular pouches of, 402. 
 
 Lloyd, L., on the polygamy of the capercailzie and bustard, 248; 
 on the numeral proportion of the sexes in the capercailzie and black- 
 cock, 280; on the salmon, 378; on the colors of the sea-scorpion, 382; 
 on the pugnacity of male grouse, 415; on the capercailzie and 
 black-cock, 416, 420; on the call of the capercailzie, 425; on assem- 
 blages of grouse and snipes, 460; on the pairing of a shield-drake 
 with a common duck, 471; on the battles of seals, 571; on the elk, 
 579. 
 
 Lobivanellus, wing-spurs in, 414. 
 
 Local influences, effect of, upon stature, 34. 
 
 Lockwood, Mr., on the development of Hippocampus, 185. 
 
 Lock wood, Rev. S., musical mouse, 648. 
 
 Locust, bright-colored, rejected by lizards and birds, 328. 
 
 Locust, migratory, 321; selection by female, 321. 
 
 Locustidje, stridulation of the 320, 322; descent of the, 323. 
 
 Locusts, proportion of sexes in, 287; stridulation of, 321. 
 
 Longicorn beetles, [difference of the sexes of, in color, 333; stridula- 
 tion of, 343. 
 
 Lonsdale, Mr., on an example of personal attachment in Helta 
 pomatia, 296. 
 
 Lophobranchii marsupial receptacles of the male, 392i 
 
 Lophophorus, habits of, 477. 
 
 Lophorina atra, sexual difference in coloration of, 559. 
 
 Lophornis ornatus, 439. 
 
 Lord, J. K., on Salmo lycaodon, 377. 
 
 Lory, King, 521 ; immature plumage of the, 532. 
 
 Lory, king, constancy of, 466. 
 
 Love-antics and dances of birds, 431. 
 
 Lowne, B. T., on Musca wmitoria, 61, 318. 
 
 Loxia, characters of young of, 529. 
 
 Lubbock, Sir J., on the antiquity of man, 2; on the origin of man, 
 3; on the mental capacity of savages, 73; on the origin of imple- 
 ments, 93; on the simplification of languages, 104; on the absence of 
 the idea of God among certain races of men, 106; on the origin of the 
 belief in spiritual agencies, 107; on superstitions, 108; on the sense 
 of duty, 111; on the practice of burying the old and sick among the 
 Fijians, 116; on the immorality of savages, 135 ; on Mr. Wallace's 
 claim to the origination of the idea of natural selection, 55; on the 
 former barbarism of civilized nations, 162; on improvements in the 
 arts among savages, 164; on resemblances of the mental characters 
 in different races of men, 203; on the arts practiced by savages, 204; 
 on the power of counting in primeval man, 204; on the prehensile 
 organs of the male Labidocera Darwinii, 301; on Chloeon, 311; on 
 Smynthurus luteus, 317; finding of new mates by jays, 463; on strife 
 for women among the North American Indians, 640; on music, 650; 
 on the ornamental practices of savages, 654; on the estimation of the 
 beard among the Anglo-Saxons, 663; on artificial deformation of the 
 skull, 565; on "communal marriages," 671; on oxogamy, 673, 676; 
 
 on the Veddahs, 675; on polyandry, 677 
 Lucanidse, variability of the mandible 
 
 es in the male, 339-
 
 760 INDEX. 
 
 Lucanus, large size of males of, 316; lucanus cervus, numerical 
 proportion of sexes of, 286 ; weapons of the male, 339; lucanus 
 elaphus, use of mandibles of, 340; large jaws of male, 312. 
 
 Lucas Prosper, on pigeons, 475; on sexual preference in horses and 
 bulls, 598. 
 
 Luminosity in insects, 314. 
 
 Lunar periods, 8, 187. 
 
 Lund, Dr., on skulls found in Brazilian caves, 192. 
 
 Lungs, enlargement of, in the Quichua and Aymara Indians, 38; 
 a modified swim-bladder, 183 ; different capacity of, in races of 
 man, 191. 
 
 Luschka, Prof., on the termination of the coccyx, 25. 
 
 Luxury, expectation of life uninfluenced by, 154. 
 
 Lyccena, sexual differences of color in species of, 351 . 
 
 Lycaense, colors of, 354. 
 
 Lyell, Sir C., on the antiquity of man, 2; on the origin of man, 3; 
 on the parallelism of the development of species and languages, 102; 
 on the extinction of languages 102; on the Inquisition, 160; on the 
 fossil remains of vertebrata, 178; on the fertility of mulattoes, 194. 
 
 Lynx, Canadian, throat-ruff of the, 594. 
 
 Lyre-bird, assemblies of, 461. 
 
 Macacus, ears of, 17; convoluted body in the extremity of the tail 
 of, 26; variability of the tail in species of, 65; whiskers of species of, 
 607; macacus brunneus, 66; macacus cynomolgus, superciliary ridge 
 of, 636; beard and whiskers of, becoming white with age, 637; 
 macacus ecaudatus, 67; macacus lasiotus, facial spots of, 629; maca- 
 cus nemenstnnus, 710; macacus radiatus, 171; macacus rhesus, sexual 
 difference in the color of, 616, 629. 
 
 Macalister, Prof., on variations of the palmaris accessorius muscle, 
 30; on muscular abnormalities in man, 47, 48; on the greater varia- 
 bility of the muscles in men than in women, 253. 
 
 Macaws, Mr. Buxton's observations on, 115, 425. 
 
 McCann, J., on mental individuality, 95. 
 
 McClelland J., on the Indian Cyprinidse, 389. 
 
 Macculloch, Col., on an Indian village without any female 
 children, 676. 
 
 Macculloch, Dr., on tertian ague in a dog, 8. 
 
 Macgillivray, W., on the vocal organs of birds, 101; on the 
 Egyptian goose, 414; on the habits of woodpeckers, 427; on the 
 habits of the snipe, 428; on the whitethroat, 432; on the moulting 
 of the snipes, 444; on the moulting of the Anatidse, 446; on the 
 finding of new mates by magpies, 453; on the pairing of a blackbird 
 and thrush, 470; on pied ravens, 482 ; on the guillemots, 482; on 
 the colors of the tits, 521; on the immature plumage of birds, 530, 
 et seq. 
 
 MficJietes, sexes and young of, 553, et seq. ; machetes pugnax, sup- 
 posed to be polygamous, 248; numerical proportion of the sexes in, 
 280; pugnacity of the male, 409; double moult in, 443. 
 
 Mclntosh, Dr., colors of the Nemertians, 299. 
 
 McKennan, marriage customs of Koraks, 684. 
 
 Mackintosh, on the moral sense, 110. 
 
 MacLachlan, K., on Apatania muiiebris and Boreus hyemal^, 287; 
 on the anal appendages of male insects, 811; on the pairing of
 
 INDEX. 761 
 
 dragon flies, 316; on dragon flies, 329; on dimorphism in Agrion, 
 329; on the want of pugnacity in male dragon flies, 330; color of 
 ghost-moth in the Shetland Islands, 359. 
 
 M'Lennan, Mr., on infanticide, 52, 675; on the origin of the belief 
 in spiritual agencies, 106; on the prevalence of licentiousness among 
 savages, 134, 671; on the primitive barbarism of civilized nations, 
 162; on traces of the custom of the forcible capture of wives, 163, 
 676; on polyandry, 677. 
 
 MacnamaTa, Mr., susceptibility of Andaman Islanders and Nepalese 
 to change, 214. 
 
 McNeill, Mr., on the use of the antlers of deer, 582; on the Scotch 
 deerhound, 589; on the long hairs on the throat of the stag, 595; on 
 the bellowing of stags, 600. 
 
 Macropus, courtship of, 387. 
 
 Macrorhinus proboscideus, structure of the nose of, 603. 
 
 Magpie, power of speech of, 101; vocal organs of the, 421; nuptial 
 assemblies of, 461; new mates found by, 462; stealing bright objects, 
 469; young of the, 548; coloration of the, 562. 
 
 Maillard, M., on the proportion of the sexes in a species of PapiKo 
 from Bourbon, 283; 
 
 Maine, Sir Henry, on the absorption of one tribe by another, 145; 
 a desire for improvement not general, 150. 
 
 Major, Dr. C. Forsyth, on fossil Italian apes, 177; skull of Bos 
 etruscus, 576; tusks of miocene pigs, 593. 
 
 Makalolo, perforation of the upper lip by the, 657. 
 
 Malar bone, abnormal division of, in man, 44. 
 
 Malay, Archipelago, marriage-customs of the savages of the, 683. 
 
 Malays, line of separation between the Papuans and the, 192; gen- 
 eral beardlessness of the, 689; staining of the teeth among, 655; 
 aversion of some, to hairs on the face, 662; and Papuans, contrasted 
 characters of, 191. 
 
 Male animals, struggles of, for the possession of the females, 239, 
 241; eagerness of, in courtship, 250, 251; generally more modified 
 than female, 250, 252; differ in the same way from females and 
 young, 263; characters, developed in females, 257; transfer of, to 
 female birds, 537; sedentary, of a hymenopterous parasite, 251, 
 
 Malefactors, 155. 
 
 Males, presence of rudimentary female organs in, 184; and females, 
 comparative numbers of, 241, 244 ; comparative mortality of, while 
 young, 244. 
 
 Malherbe, on the woodpeckers, 521. 
 
 Mallotus Pe/wm,376; mllosus, 375. 
 
 Malthus, T., on the rate of increase of population, 50, 51, 52. 
 
 Maluridse, nidification of the, 517. 
 
 Malurus, young of, 553. 
 
 Mammae, 235; rudimentary, in male mammals, 12, 26, 183, 184, 
 185; supernumerary, in women, 41; of male human subject, 42. 
 
 Mammalia, Prof. Owen's classification of, 168; genealogy of the. 
 180. 
 
 Mammals, recent and tertiary, comparison of cranial capacity of, 
 62; nipples of, 184; pursuit of female, by the males, 250; secondary 
 sexual characters of, 570; weapons of, 571; relative size of the sexes 
 of, 588; parallelism of, with birds in secondary sexual characters, 
 6,18; voioe o|, u,se4 especially during the breeding season, 647.
 
 762 INDEX. 
 
 Man, variability of, 29; erroneously regarded as more domesticated 
 than other animals, 31; migrations of, 53; wide distribution of, 53; 
 causes of the nakedness of, 63; supposed physical inferiority of, 72; 
 a member of the Catarrhine group, 176; early progenitors of, 182; 
 transition from ape indefinite, 205; numerical proportions of the 
 sexes in, 243; difference between the sexes, 252; proportion of sexes 
 among the illegitimate, 276 ; different complexion of male and 
 female negroes, 634 ; secondary sexual characters of, 634; primeval 
 condition of, 678. 
 
 Mandans, correlation of color and texture of hair in the, 225. 
 
 Mandible, left, enlarged in the male of Taphroderes distortus, 313. 
 
 Mandibles, use of the, in Ammophila, 312; large, of Corydalie 
 cornutns, 312; large, of male Lucanus elaphus, 312. 
 
 Mandrill, number of caudal vertebrae in the, 65; colors of the male, 
 614, 617, 629. 
 
 Mantegazza, Prof., on last molar teeth of man, 22; bright colors 
 in male animale, 254; on the ornaments of savages, 654 et scq.; on 
 the beardlessness of the New Zealanders, 663; on the exaggeration 
 of natural characters by man, 664. 
 
 Mantell, W., on the engrossment of pretty girls by the New Zea- 
 land chiefs, 680. 
 
 Mantis, pugnacity of species of, 710. 
 
 Maories, mortality of, 210; infanticide and proportion of sexes, 
 289; distaste for hairiness among men, 663; 
 
 Marcus Aurelius, on the origin of the moral sense, 111; on the 
 influence of habitual thoughts, 139. 
 
 Mareca pe nelope, 471. 
 
 Marks, retained throughout groups of birds, 485. 
 
 Marriage, restraints upon, among savages, 50; influence of, upon 
 morals, 134; influence of, on mortality, 157; development of, 673. 
 
 Marriages, early, 156 et seq.; commual, 670, 672. 
 
 Marshall, Dr. W., protuberances on birds' heads, 266, 435; on the 
 moulting of birds, 445; advantage to older birds of paradise, 552; 
 Marshall, Col., interbreeding among Todas, 215; infanticide and 
 proportion of sexes with Todas, 288 ; choice of husband among 
 Todas, 677; Marshall, Mr., on the brain of a Bush woman, 191. 
 
 Marsupials, 179; development of the nictitating membrane in, 19; 
 uterus of, 43 ; possession of nipples by, 185 ; their origin from 
 Monotremata, 188; abdominal sacs of, 235; relative size of the sexes 
 of, 588; colors of, 609. 
 
 Marsupium, rudimentary, in male marsupials, 183. 
 
 Martin, W. C. L., on alarm manifested by an orang at the sight of 
 a turtle, 81; on the hair in Hylobates, 172; on a female American 
 deer, 586; on the voice of Hylobates agilis, 602; on Semnopithecut 
 nemceus, 630; on the beards of the inhabitants of St. Kilda, 638. 
 
 Martins deserting their young, 122. 
 
 Martin, C., on death caused by inflammation of the vermiform 
 appendages, 23. 
 
 Mastoid processes in man and apes, 59. 
 
 Maudsley, Dr., on the influence of the sense of smell in man, 20; 
 on idiots smelling their food, 41; on Laura Bridgman, 99; on the 
 development of the vocal organs, 101; moral s,ense failing in 
 incipient madness, 140; change of mental faculties at puberty in man, 
 644.
 
 INDEX. 763 
 
 Mayers, W. P. , on the domestication of the goldfish in China, 389. 
 Mayhew, E., on the affection between individuals of different sexes 
 in the dog, 596. 
 
 Maynard, C. J., on the sexes of Chrysemys picta, 397. 
 
 Meckel, on correlated variation of the muscles of the arm and 
 leg, 49. 
 
 Medicines, effect produced by, the same in man and in monkeys, 7. 
 
 Medusce, bright colors of some, 295. 
 
 Megalithic structures, prevalence of, 204. 
 
 Megapicus validus, sexual difference of color in, 521. 
 
 Megasoma, large size of males of, 316. 
 
 Meigs. Dr. A., on variation in the skulls of the natives of 
 America, 29. 
 
 Meinecke, on the numerical proportion of the sexes in butter- 
 flies, 283. 
 
 Melanesians, decrease of, 211. 
 
 Meldola, Mr., colors and marriage flight of Colias and Pieris, 362. 
 
 Meliphagidae, Australian nidification of, 517. 
 
 Melita, secondary sexual characters of, 303. 
 
 Meloe, difference of color in the sexes of a species of, 333. 
 
 Meinnon, young, 192. 
 
 Memory, manifestations of, in animals, 83. 
 
 Mental characters, difference of, in different races of men, 191; 
 faculties, diversity of, in the same race of men, 30; inheritance of, 
 31; variation of, in the same species, 31, 74; similarity of the, in dif- 
 ferent races of man, 203; of birds, 466; powers, difference of, in the 
 two sexes in man, 642. 
 
 Menura Alberti, 461; song of, 421; menura superba, 461; long 
 tails of both sexes of, 513. 
 
 Merganser, trachea of the male, 425; merganser serrator, male 
 plumage of, 446. 
 
 Mergus cucullatm, speculum of, 267; mergus merganser, young 
 of, 532. 
 
 Metallura, splendid tail-feathers of, 503. 
 
 Methoca ichneumonides, large male of, 316. 
 i, Meves, M., on the drumming of the snipe, 428. 
 
 Mexicans, civilization of the, not foreign, 164. 
 
 Meyer, on a convoluted body at the extremity of the tail in a 
 Macacus and a cat, 25. 
 
 Meyer, Dr. A., on the copulation of Phryganida? of distinct 
 species, 312. 
 
 Meyer, Prof. L., on development of helix of ear, 16 et seq.; men's 
 ears more variable than women's, 253; antennae serving as ears, 318. 
 
 Migrations of man, effects of, 53. 
 
 Migratory instinct of birds, 119; vanquishing the maternal, 122, 128. 
 
 Mill, J. S., on the origin of the moral sense, 111; on the "greatest 
 happiness principle," 135; on the difference of the mental powers in 
 the sexes of man, 644. 
 
 Millipedes, 310. 
 
 Milne-Edwards H., on the use of enlarged chelae of the male 
 Qelammus, 303. 
 
 Milvago leucurus, sexes and young of, 546. 
 
 Mimicry, 366.
 
 764 INDEX. 
 
 Mimus polyglottus, 467. 
 
 Mind, difference of, in man and the highest animals, 143; similarity 
 of the, in different races, 203. 
 
 Minnow, proportion of the sexes in the, 282. 
 
 Mirror, behavior of monkeys before, 709. 
 
 Mirrors, larks attracted by, 469. 
 
 Mitchell, Dr., interbreeding in the Hebrides, 215. 
 
 Mitford, selection of children in Sparta, 32. 
 
 Mivart, St. George, on the reduction of organs, 13; on the ears of 
 the lemuroidea, 17; on variability of the muscles in lemuroidea, 46, 
 54; on the caudal vertebrae of monkeys, 65; on the classification of 
 the primates, 174; on the orang and on man, 175; on differences in 
 the lemuroidea, 176; on the crest of the male newt, 395. 
 
 Mobius, Prof. , on reasoning powers in a pike, 85. 
 
 Mocking-thrush, partial migration of, 467; young of the, 554. 
 
 Modifications, unserviceable, 69. 
 
 Moggridge, J. T., on habits of spiders, 77; on habits of ants, 168. 
 
 Moles, numerical proportion of the sexes in, 279; battles of 
 male, 570. 
 
 Mollienesia petenensis, sexual difference in, 382. 
 
 Mollusca, beautiful colors and shapes of, 298; absence of secondary 
 sexual characters in the, 296. 
 
 Molluscoida, 181, 296. 
 
 Monacanthus scopas and M. Peronii, 376. 
 
 Monboddo, Lord, on music, 653. 
 
 Mongolians, perfection of the senses in, 38. 
 
 Monkey, protecting his keeper from a baboon, 117, 125; bonnet, 
 171; rhesus, sexual difference in color of the, 615, 629; mustache, 
 colors of the, 614. 
 
 Monkeys, liability of, to the same diseases as man, 7; male, recog- 
 nition of women by, 9; diversity of the mental faculties in, 31; 
 breaking hard fruits with stones, 56; hands of the, 56, 57; basal 
 caudal vertebrae of, imbedded in the body, 66; revenge taken by, 78; 
 maternal affection in, 79; variability of the faculty of attention in, 
 83; American, manifestation of reason in, 87 ; using stones and 
 sticks, 91; imitative faculties of, 98; signal-ries of, 98; mutual 
 kindnesses of, 115; sentinels posted by, 114; human characters of, 
 171; American, direction of the hair on the arms of some, 172; grada- 
 tion of species of, 199; beards of, 607; ornamental characters of, 
 626; analogy of sexual differences of, with those of man, 636; 
 different degrees of difference in the sexes of, 640; expression of 
 emotions by, 652; generally monogamous habits of, 674; polygamous 
 habits of some, 674; naked surfaces of, 686; courtship of, 709. 
 
 Monogamy, not primitive, 164. 
 
 Monogenists, 200. 
 
 Mononychits pseudacori, stridulation of, 345. 
 
 Monotreniata, 179; development of the nictitating membrane 
 in, 19; lactiferous glands of, 184; connecting mammals with reptiles, 
 188. 
 
 Monstrocities, analogous in man and lower animals, 33; caused by 
 arrest of development, 40; correlation of, 49; transmission of, 197. 
 
 Montagu, (i., on the habits of the black and red grouse, 248; on 
 the pugnacity of the ruff, 409, 410; on the singing of birds, 418^ OU 
 ^b,e double moult of the male pintail, 44ft-
 
 INDEX. 765 
 
 Monteiro, Mr., on the Bucorax abyssinicus, 435. 
 
 Monies de Oca, M., on the pugnacity of male humming-birds, 408. 
 
 Monticola cyanea, 519. 
 
 Monuments, as traces of extinct tribes, 206. 
 
 Moose, battles of, 571; horns of the, an incumberance, 587. 
 
 Moral and instinctive impulses, alliance of, 125; faculties, their in- 
 fluence on natural selection in man, 144; rules, distinction between 
 the higher and lower, 138; sense, so-called, derived from the social 
 instincts, 136; origin of the, 140; tendencies, inheritance of, 140. 
 
 Morality, supposed to be founded in selfishness, 135; test of, the 
 general warfare of the community, 137; gradual rise of, 141; in- 
 fluence of a high standard of, 149. 
 
 Morgan, L. H., on the beaver, 75; on the reasoning powers of the 
 beaver, 84; on the forcible capture of wives, 163; on the castoreum 
 of the beaver, 604; marriage unknown in primeval times, 671; on 
 polyandry, 677. 
 
 Morley, J., on the appreciation of praise and fear of blame, 162. 
 
 Morris, F. O. , on hawks feeding an orphan nestling, 465. 
 
 Morse, Dr., colors of mollusca, 298. 
 
 Morselli, E. , division of the malar bone, 44. 
 
 Mortality, comparative, of female and male, 244, 275. 
 
 Morton, on the number of species of man, 199. 
 
 Moschkau, Dr. A., on a speaking starling, 96. 
 
 Moschus moschiferus, odoriferous organs of, 605. 
 
 Motaciilce, Indian, young of, 534. 
 
 Moth, odoriferous, 349. 
 
 Moths, 355; absence of mouth in some males, 235; apterous female, 
 235; male, prehensile use of the tarsi by, 237; male, attracted by 
 females, 284; sound produced by, 349; coloration of, 357; sexual dif- 
 ferences of color in, 358. 
 
 Motmot, inheritance of mutilation of tail feathers, 67, 689; racket- 
 shaped feathers in the tail of a, 436. 
 
 Moult, double, 526; double annual, in birds, 443. 
 
 Moulting of birds, 551. 
 
 Moults, partial, 444. 
 
 Mouse, song of, 648. 
 
 Mustache-monkey, colors of the, 614, 630. 
 
 Mustaches, in monkeys, 171. 
 
 Mud-turtle, long claws of the male, 397. 
 
 Mulattoes, persistent fertility of, 194; immunity of, from yellow 
 fever, 220. 
 
 Mule, sterility and strong vitality of the, 195. 
 
 Mules, rational, 88. 
 
 Miiller, Ferd., on the Mexicans and Peruvians, 164; Fritz; on asto- 
 jnatous males of Tanais, 235; on the disappearance of spots and 
 stripes in adult mammals, 625; on the proportions of the sexes in 
 some Crustacea, 287 ; on secondary sexual characters in various 
 Crustaceans, 300, et seq.; musical contest between male Cicidce, 320; 
 mode of holding wings in Castina, 357; on birds showing a preference 
 for certain colors, 359; on the sexual maturity of young amphipod 
 Crustacea, 552. 
 
 Muller, Hermann, emergence of bees, from pupa, 242; pollen- 
 gathering of bees, 258; proportion of sexes in bees, 286; courting of
 
 ?66 INDEX. 
 
 EristaUs, 318; color and sexual selection with bees, 331; J., on the 
 nictitating membrane and semilunar fold, 19; Max, on the origin of 
 language, 98; language implies power of general conception, 100; 
 struggle for life among the words, etc., of languages, 102; S., on the 
 banteng, 613; on the colors of Semnopithecus chrysomelas, G13. 
 
 Muntjac-deer, weapons of the, 586. 
 
 Murie, J., on the reduction of organs, 13; on the ears of the Lemu- 
 roidea, 17; on variability of the muscles in the Lemuroidea, 46, 54; 
 basal caudal vertebrae of Macacus brunneus imbedded in the body, 
 67; on the manner of sitting in short-tailed apes, 67; on differences 
 in the Lemuroidea, 176 : on the throat-pouch of the male bustard, 
 423; on the mane of Otaria jubata, 594; on the sub-orbital pits of 
 Ruminants, 605; on the colors of the sexes in Otaria nigrescens, 610. 
 
 Murray, A., on the Pediculi of different races of men, 193; T. A,, 
 on the fertility of Australian women with white men, 194. 
 
 Mus coninga, 91 ; minutus, sexual difference in the color of, 610. 
 
 Musca vomitoria, 61. 
 
 Muscicapa grisola, 518; luctuosa, 518; ruticiUa, breeding in imma- 
 ture plumage, 551. 
 
 Muscle, ischio-pubie, 46. 
 
 Muscles, rudimentary, occurrence of, in man, 13 ; variability of 
 the 30; effects of use and disuse upon, 36; animal-like abnormalities 
 of, in man, 46; correlated variation of, in the arm and leg, 49; variability 
 of, in the hands and feet, 54; of the jaws, influence of, on the phy- 
 siognomy of the apes, 50; habitual spasms of, causing modifications of 
 the facial bones, 62; of the early progenitors of man, 182; greater 
 variability of the, in men than in women, 252. 
 
 Muculus sternalis, Prof. Turner, on the, 14. 
 
 Music, 203; of bird, 417, discordant, love of savages for, 431; 
 reason of power of perception of notes in animals, 648; power of dis- 
 tinguishing notes 649; its connection with primeval speech, 652; dif- 
 ferent appreciation of, by different peoples, 651; origin of, 650, 653; 
 effects of, 651. 
 
 Musical cadences, perception of, by animals, 649; powers of man, 
 645, et seq. 
 
 Musk-deer, canine teeth of male, 572, 586; male, odoriferous 
 organs of the, 604; winter change of the, 619. 
 
 Musk-duck, Australian, 407; large.size of male, 411; of Guiana, 
 pugnacity of the male, 411. 
 
 Musk-ox, horns of, 576. 
 
 Musk-rat, protective resemblance of the, to a clod of earth, 619. 
 
 Musophagve, colors and nidification of the, 518; both sexes of, 
 equally brilliant, 523. 
 
 Mussels opened by monkeys, 56. 
 
 Muxtda, winter change of two species of, 619. 
 
 Musters, Capt., on Rlwa Darwinii, 545; marriages among Pata- 
 gonians, 683. 
 
 Mutilations, healing of, 8; inheritance of, 67. 
 
 Mutttla europcea, stridulation of, 332. 
 
 Mutillidae, absence of ocelli in female, 311. 
 
 Mycetes caraya, polygamous, 245; vocal organs of, 602; beard of, 
 607; sexual differences of color in, 613; voice of, 647; mycetes seni- 
 culus, sexual differences of color in, 613.
 
 INDEX. 767 
 
 Myriapoda, 310. 
 Naereli, on 
 
 Nageli, on the influence of natural selection on plants, 68; on the 
 gradation of species of plants, 199. 
 
 Nails, colored yellow or purple in part of Africa, 655. 
 
 Narwhal, tusks of the, 572, 578. 
 
 Nasal cavities, large size of, in American aborigines, 38. 
 
 Nascent organs, 12. 
 
 Nathusius, H. von, on the improved breeds of pigs, 201 ; male 
 domesticated animals more variable than females, 252 ; horns of 
 castrated sheep, 577; on the breeding of domestic animals, 680. 
 
 Natural selection, its effects on the early progenitors of man, 53.- 
 influence of, on man, 67, 70 ; limitation of the principle, 68; in 
 fluence of, on social animals, 70; Mr. Wallace on the limitation of, 
 by the influence of the mental faculties in man, 144; influence of, 
 in the progress of the United States, 161; in relation to sex, 292. 
 
 Natural and sexual selection contrasted, 256. 
 
 Naulette, jaw from, large size of the canines in, 46. 
 
 Neanderthal skull, capacity of the, 61. 
 
 Neck, proportion of, in soldiers and sailors, 36. 
 
 Necrophorus, stridulation of, 342, 345. 
 
 Neetarinia, young of, 533. 
 
 Necta/rinice, moulting of the, 444; nidification of, 517. 
 
 Negro, resemblance of a, to Europeans in mental characters, 203. 
 
 Negro-women, their kindness to Mungo Park, 133. 
 
 Negroes, Caucasian features in, 190; character of, 191; lice of, 193; 
 fertility of, when crossed with other races, 194; blackness of, 194, 
 197; variability of, 198, 199; immunity of, from yellow fever, 220; 
 difference of, from Americans, 224; disfigurements of the, 617; color 
 of new-born children of, 635; comparative beardlessness of, 639; 
 readily become musicians, 650; appreciation of beauty of their women 
 by, 659, 661; idea of beauty among, 664; compression of the nose by 
 some, 665. 
 
 Nernertians, colors of, 299. 
 
 Neolithic period, 164. 
 
 Neomorpha, sexual difference of the beak in, 408. 
 
 NepMa, size of male, 309. 
 
 Nests, made by fishes, 391; decoration of, by humming-birds, 469. 
 
 Neumeister, on a change of color in pigeons after several rnoult- 
 ings, 269. 
 
 Neuration, difference of, in the two sexes of some butterflies and 
 hymenoptera, 314. 
 
 Neuroptera, 287, 327. 
 
 Neurothemis, dimorphism in, 329. 
 
 New Zealand, expectation by the natives of, of their extinction, 
 218; practice of tattooing in, 657; aversion of natives of, to hairs on 
 the face, 662; pretty girls engrossed by the chiefs in, 680. 
 
 Newton, A., on the throat-pouch of the male bustard, 423; on the 
 difference between the females of two species of Oxynotus, 536; on 
 the habits of the Phalarope, dotterel and godwit, 544. 
 
 Newts, 394. 
 
 Nicholson, Dr., on the non-immunity of dark Europeans from 
 yellow fever, 222. 
 
 Nictitating membrane, 19, 182.
 
 768 INDEX. 
 
 Nidification, of fishes, 391; relation of, to color, 515, 519; of 
 British birds, 517. 
 
 Night-heron, cries of the, 417. 
 
 Nightingale, arrival of the male before the female, 240; object of 
 the song of the, 418. 
 
 Nightingales, new mates found by, 463. 
 
 Nightjar, selection of a mate by the female, 473; Australian, sexs 
 of, 546; coloration of the 559. 
 
 Nightjars, noise made by some male, with their wings, 426; elon- 
 gated feathers in, 436, 457. 
 
 Nilghau, sexual differences of color in the, 611. ! 
 
 Nillson, Prof., on the resemblance of stone arrow-heads from 
 various places, 203; on the development of the horns in the rein- 
 deer, 265. 
 
 Nipples, absence of, in Monotremata, 184. 
 
 Nitsche, Dr., ear of fetal orang, 18. 
 
 Nitzsch, C. L., on the down of birds, 442. 
 
 Noctuae, brightly colored beneath, 357. 
 
 Noctuidae, coloration of, 355. 
 
 Nomadic habits, unfavorable to human progress, 150. 
 
 Nordmann, A., on Tetrao urogalloides, 460. 
 
 Norfolk Island, half-breeds on, 217. 
 
 Norway, numerical proportion of male and female births in, 275. 
 
 Nose, "resemblance of, in man and the apes, 174; piercing and 
 ornamentation of the, 656; very flat, not admired in negroes, 664; 
 flattening of the, 665. 
 
 Nott and Gliddon, on the features of Ramesis II, 192; on the 
 features of Amunoph III, 192; on skulls from Brazilian caves, 192; 
 on the immunity of negroes and inulattoes from yellow fever, 
 220; on the deformation of the skull among American tribes, 665. 
 
 Nudibranch Mollusca, bright colors of, 296. 
 
 Numerals, Roman, 163. 
 
 Nunemaya, natives of, bearded, 639. 
 
 Nuthatch, of Japan, intelligence of, 466; Indian, 555. 
 
 Obedience, value of, 147. 
 
 Observation, powers of, possessed by birds, 467. 
 
 Occupations, sometimes a cause of diminished stature, 34; effect 
 of, upon the proportions of the body, 34. 
 
 Ocelli, absence of, in female Mutillidae, 311; of birds, formation 
 and variability of the, 486. 
 
 Ocelot, sexual differences in the coloring of the, 610. 
 
 Ocyphaps Iophotes,4i56. 
 
 Odonata, 287. < 
 
 Odonestis potatoria, sexual difference of color in, 358. 
 
 Odor, correlation of, with color of skin, 225; of moths, 349; 
 emitted by snakes in the breeding-season, 399; of mammals, 603. 
 
 (Ecanthus nivalis, difference of color in the sexes of, 328; cecanthus 
 pellucidus, 328. 
 
 Ogle, Dr. W. , relation between color and power of smell, 19. 
 
 Oidemia, 559. 
 
 Olivier, on sounds produced by Pimelia striata, 347. 
 
 Omaloplia brunnea, stridulation of, 344. 
 
 Onitis furcifer, processes of anterior femora of the male, and on 
 the fcead and thorax of the female, 337, 338.
 
 INDEX. 769 
 
 Onthophagus, 336; onthophagus rangifer, sexual differences of, 335; 
 variation in the horns of the male, 336. 
 
 Ophidia, sexual differences of, 398. 
 
 Ophidium, 394. 
 
 Opossum, wide range of, in America, 193. 
 
 Optic nerve, atrophy of the, caused by destruction of the eye, 36. 
 
 Orang-outang, 640; Bischoff on the agreement of the'brain of the, 
 with that of man, 6; adult age of the, 9; ears of the, 15; vermiform 
 appendage of, 23; hands of the, 56; absence of mastoid processes in 
 the, 59; platforms built by the, 75; alarmed at the sight of a turtle, 
 81; using a stick as a lever, 91; using missiles, 92; using the leaves 
 of the Pandanus as a night covering, 93; direction of the hair on 
 the arms of the, 172; its aberrant characters, 175; supposed evolu- 
 tion of the, 202; voice of the, 602; monogamous habits of the, 674; 
 male, beard of the, 607. 
 
 Oranges, treatment of, by monkeys, 56. 
 
 Orange tip butterfly, 350, 354. 
 
 Orchestia Danvinii, dimorphism of males of, 303 ; orchestia 
 tucuratinga, limbs of, 302, 307. 
 
 Ordeal, trial by, 108. 
 
 Oreas canna, colors of 612; areas derbianus, colors of, 612, 621. 
 
 Organs, prehensile, 237; utilized for new purposes, 651. 
 
 Organic scale, von Baer's definition of progress in, 186. 
 
 Orioles, nidification of, 516. 
 
 Oriolus, species of, breeding in immature plumage, 552; wiolua 
 melanocephalus, coloration of the sexes in, 524. 
 
 Ornaments, prevalence of similar, 2C3; of male birds, 416; fond- 
 ness of savages for, 654. 
 
 Ornamental characters, equal transmission of, to both sexes, in 
 mammals, 619; of monkeys, 626. 
 
 Ornithoptera crcesus, 283. 
 
 Ornithorynchus, 178 ; reptilian tendency of, 180 ; spur of the 
 male, 573. 
 
 Orocetes erythrogastra, young of, 554. 
 
 Orrony, Grotto of, 24. 
 
 Orsodacna atra, difference of color in the sexes of, 333; orsodacna, 
 ruficollis, 333. 
 
 Orthoptera, 320; metamorphosis of, 268; stridulating apparatus of, 
 321, 326; colors of, 327; rudimentary stridulating organs in female, 
 326; stridulation of the, and Homoptera, discussed, 327. 
 
 Ortygornis gularis, pugnacity of the male, 412. 
 
 Oryctes, stridulation of, 344; sexual differences in the stridulant 
 organs of, 345. 
 
 Oryx lemoryx, use of the horns of, 580, 585, 590. 
 
 Osphranter rufus, sexual difference in the color of, 609. 
 
 Ostrich, African, sexes and incubation of the, 544. 
 
 Ostriches, stripes of young, 529. 
 
 Otanajubata, mane of the male, 594; otaria nigrescent, difference 
 in the coloration of the sexes of, 610. 
 
 Otis bengalensis, love-antics of the male, 432; otis tarda, throat- 
 pouch of the male, 423; polygamous, 248. 
 
 Ouzel, ring, colors and niditication of the, 518; water, singing in 
 the autumn, 420; colors and nidification of the, 518.
 
 770 INDEX. 
 
 Ovibos moschatus, horns of, 576. 
 
 Ovipositor of insects, 235. 
 
 Oms cycloceros, mode of fighting of, 579, 585. 
 
 Ovule of man, 9. 
 
 Owen, Prof. , on the Corpora Wolffiana, 10; on the great toe in 
 man, 10; on the nictitating membrane and semilunar fold, 19; on the 
 development of the posterior molars in different races of man, 22; 
 on the length of the ccecuin in the Koala, 23; on the coccygeal verte- 
 brae, 25; on rudimentary structures belonging to the reproductive 
 system, 26; on abnormal conditions of the human uterus, 43; on the 
 number of digits in the Ichthyopterygia, 42; on the canine teeth in 
 man, 45; on the walking of the chimpanzee and orang, 56; on the 
 mastoid processes in the higher apes, 59; on the hairiness of ele- 
 phants in elevated districts, 64; on the caudal vertebras of monkeys, 
 65; classification of mammalia, 168; on the hair in monkeys, 171; on 
 the piscine affinities of the Ichthyosaurians, 180; on polygamy and 
 monogamy among the antelopes, 246; on the horns of Antilocapra 
 americana, 265; on the musky odor of the crocodiles during the 
 breeding- season, 398; on the scent-glands of snakes, 399; on the 
 Dugong, Cachalot and Ornithwhynclms, 572, 573; on the antlers of 
 the red deer, 582; on the dentition of the Canielidse, 586; on the 
 horns of the Irish elk, 587; on the voice of the giraffe, porcupine and 
 stag, 600; on the laryngeal sac of the gorilla and oraug, 602; on the 
 odoriferous glands of mammals, 604, 605; on the effects of emascula- 
 tion on the vocal organs of men, 645; on the voice of Hylobates 
 agilis, 647 ; on American monogamous monkeys, 674. 
 
 Owls, white, new mates found by, 463. 
 
 Oxynotus, difference of the females of two species of, 536. 
 
 Pachydermata, 247. 
 
 Pachytylus migratorius. 321. 
 
 Paget, on the abnormal development of hairs in man, 20; on the 
 thickness of the skin on the soles of the feet of infants, 37. 
 
 Pagurus, carrying the female, 303. 
 
 Painting, pleasure of savages in, 203. 
 
 Palcemon, chelae of a species of, 302. 
 
 Palceornis, sexual differences of color in, 562; palceornis javanicus, 
 color of beak of, 525; palceornis rosa, young of, 532. 
 
 Palamedea cornuta, spurs on the wings, 414. 
 
 Paleolithic period, 164. 
 
 Palestine, habits of the chaffinch in, 281. 
 
 Pallas, on the perfection of the senses in the Mongolians, 38; on 
 the want of connection between climate and the color of the skin, 
 219; on the polygamous habits of AntUope Saiga, 246; on the lighter 
 color of horses and cattle in winter in Siberia, 260; on the tusks of 
 the musk-deer, 586; on the odoriferous glands of mammals, 604; on 
 the odoriferous glands of the musk-deer, 605; on winter changes 
 of color in mammals, 619; on the ideal of female beauty in North 
 China, 659. 
 
 Palmaris at-cessorius, muscle variations of the, 30. 
 
 Pampas, horses of the, 206. 
 
 Pangenesis, hypothesis of, 258, 261. 
 
 Pannicul'is carnosus, 14. 
 
 Pansch, on the brain of a foetal Cebus apella, 233.
 
 INDEX, 771 
 
 Papilio, proportion of the sexes in North American species of, 283; 
 sexual differences of coloring in species of, 351; coloration of the 
 wings in species of, 354. 
 
 Papilio ascanius, 251; papilio sesostris and chUdrencs, variability 
 of, 362, papilio ttirnus, 283. 
 
 Papilionidae, variability in the, 362. 
 
 Papuans, line of separation between the, and the Malays, 192; 
 beards of the, 639; hair of, 655; and Malays, contrast in characters 
 of, 191. 
 
 Paradise, birds of, 460, 526; supposed by Lesson to be polygamous, 
 248; rattling of their quills by. 426; racket-shaped feathers in, 437; 
 sexual differences in color of, 438; decomposed feathers in, 437, 457: 
 display of plumage by the male, 449; sexual differences in color of- 
 559. 
 
 Paradisea apoda, barbless feathers in the tail of, 437; plumage of, 
 438; and P. papuana, 437, 438; divergence of the females of, 535; 
 increase of beauty with age, 552 ; paradisea papuana, plumage 
 of, 535. 
 
 Paraguay, Indians of, eradication of eyebrows and eyelashes 
 by, 662. 
 
 Parallelism of development of species and languages, 102. 
 
 Parasites, on man and animals, 8; as evidence of specific 
 identity or distinctness, 193; immunity from, correlated with color, 
 220. 
 
 Parental feeling in earwigs, star-fishes and spiders, 120; affection, 
 partly a result of natural selection, 119. 
 
 Parents, age of, influence upon sex of offspring, 277. 
 
 Parinee, sexual difference of color in, 521. 
 
 Park,; Mungo, negro-women teaching their children to love the 
 truth, 133; his treatment by the negro-women, 133, 642; on negro 
 opinions of the appearance of white men, 660. 
 
 Parker, Mr., no bird or reptile in line of mammalian descent, 179. 
 
 Paroquet, young of, 525, 549 ; Australian, variation in the color of 
 the thighs of a male, 481. 
 
 Parrot, racket-shaped feathers in the tail of a, 436; instance of 
 benevolence in a, 467. 
 
 Parrots, change of color in, 68; imitative faculties of, 82; living 
 in triplets, 464; affection of, 467; colors and nidifications of the, 518, 
 520, 521; immature plumage of the, 532; colors of, 557; sexual dif- 
 ferences of color in, 562; musical powers of, 651. 
 
 Parthenogenesis in the Tenthredinse, 286 ; in Cynipidse, 286; in 
 Crustacea, 287. 
 
 Partridge, monogamous, 248; proportion of the sexes in the, 280; 
 Indian, 412; female, 538; "dances," 431, 460. 
 
 Partridges, living in triplets, 464; spring coveys of male, 464; dis- 
 tinguishing persons, 467. 
 
 Parus c&ruleus, 521. 
 
 Passer, sexes and young of, 550; passer bracliydactylus, 550; passer 
 domesticus, 518, 550; passer montanus, 518, 550. 
 
 Patagonians, self-sacrifice by, 126; marriages of, 683. 
 
 Patterson, Mr., on the Agrionidae, 329. 
 
 Patteson, Bishop, decrease of Melanesians, 211. 
 
 Pavo cristatus, 267, 489; pavo muticus, 267 489; possession of 
 spurs by the female, 413, 511; paw nigripennii, 470.
 
 772 INDEX. 
 
 Payaguas Indians, thin legs and thick arms of the, 37. 
 
 Payan, Mr., on the proportion of the sexes in sheep, 279. 
 
 Peacock, polygamous, 248; sexual characters of, 267; pugnacity of 
 the, 413; Javan, possessing spurs, 413; rattling of the quills by, 426; 
 elongated tail-coverts of the, 435, 457; love of display of the, 
 447, 490; ocellated spots of the, 489; inconvenience of long tail of 
 the, to the female, 505, 513, 514; continued increase of beauty 
 of the, 552; butterfly, 354. 
 
 Peafowl, preference of females for a particular male, 475; first 
 advances made by the female, 477. 
 
 Pediculi of domestic animals and man, 193. 
 
 Pedigree of man, 188. 
 
 Pedionomus tarquatus, sexes of, 542. 
 
 Peel, J., on horned sheep, 576. 
 
 Peewit, wing-tubercles of the male, 414. 
 
 Pelagic animals, transparency of, 295. 
 
 Pelecanus erythrorhynchus, horny crest on the beak of the male, 
 during the breeding-season, 442; pelecanus onocrotalus, spring 
 plumage of, 446. 
 
 Pelele, an African ornament, 657. 
 
 Pelican, blind, fed by his companions, 116; young, guided by old 
 birds, 116; pugnacity of the male, 411. 
 
 Pelicans, fishing in concert, 114. 
 
 Pelobius Ilermanni, stridulation of, 343, 345. 
 
 Pelvis, alteration of, to suit the erect attitude of man, 59; differ- 
 ences of the, in the sexes of man , 635. 
 
 Penelope nigra, sound produced by the male, 429. 
 
 Pennant, on the battles of seals, 571; on the bladder- nose 
 seal, 603. 
 
 Penthe, antennal cushions of the male, 313. 
 
 Perch, brightness of the male, during breeding-season, 386. 
 
 Peregrine falcon, new mate found by, 463. 
 
 Period of variability, relation of, to sexual selection, 271. 
 
 Periodicity, vital, Dr. Lay cock on, 8. 
 
 Periods, lunar, followed by functions in man and animals, 8, 187; 
 of life, inheritance at corresponding, 258, 262. 
 
 Perisoreus canadensis, young of, 549. 
 
 Peritnchia, difference of color in the sexes of a species of, 333. 
 
 Periwinkle, 296. 
 
 Pernis cristata, 481. 
 
 Perrier, M., on sexual selection, 237; on bees, 332, 
 
 Perseverance, a characteristic of man, 644. 
 
 Persians, said to be improved by intermixture with Georgians ant 
 Circassians, 669. 
 
 Personnat, M., on Bombyx Yamamai, 283. 
 
 Peruvians, civilization of the, not foreign, 164 
 
 Petrels, colors of, 562. 
 
 Petroeincla cyanea, young of, 554. 
 
 Petrocossyphus, 525. 
 
 Petronia, 550. 
 
 Pfeiffer, Ida, on Javan ideas of beauty, 661, 
 
 PhacocJiwrus athiopicus, tusks and pads of, 592. 
 
 Phalanger, Vulpine, black varieties of the, 616.
 
 INDEX. 773 
 
 Phalaropus fulicarius, 544; phalaropus hyperboreus, 544. 
 PhanatU, 338; phanceus carnifex, variation of the horna of the 
 male, 336; phanceus faunus, sexual difference of, 335; phanceui 
 lancifer, 336. 
 
 Paaseolarctus cinereus, taste for rum and tobacco, 7. 
 
 Phasgonura mridissima, stridulation of, 322, 323. 
 
 Phasianus Sfemmerringii, 507; phasianus versicolor, 449: phasianus 
 Wallichii, 454, 538. 
 
 Pheasant, polygamous, 248; and black grouse, hybrids of, 470; 
 production of hybrids with the common fowl, 477; immature 
 plumage of the, '532; Amherst, display of, 449; Argus 435, 526; 
 display of plumage by the male, 451; ocellated spots of the, 488, 
 493; gradation of characters in the, 493; blood, 413; cheer, 454; 
 eared, 267, 454, 538; length of the tail in the, 513; sexes alike in 
 the, 524 ; fire-backed, possessing spurs, 413 ; golden, display of 
 plumage by the male, 449; age of mature plumage in the, 551; sex 
 of young, ascertained by pulling out head-feathers, 551; Kalij, 
 drumming of the male, 426, 533; Reeve's, length of the tail in, 514; 
 silver, triumphant male, deposed on account of spoiled plumage, 
 476 , sexual coloration of the, 560 ; Scemmerring's, 507, 514 ; 
 Tragopan, 434; display of plumage by the male, 451; marking of the 
 sexes of the, 487. 
 
 Pheasants, period of acquisition of male characters in the 
 family of the, 266; proportion of sexes in chicks of, 280; length of 
 the tail in, 507, 513, 514. 
 
 Philters, worn by women, 659. 
 
 Phoca grcenlandica, sexual difference in the coloration of, 611. 
 
 Phwnicura ruticilla, 464. 
 
 Phosphorescence of insects, 314. 
 
 Phryganidae, copulation of distinct species of, 313. 
 
 Phryniscus nigricans, 396. 
 
 Physical inferiority, supposed, of man, 67. 
 
 Pickering, on the number of species of man, 199. 
 
 Picton, J. A., on the soul of man, 700. 
 
 Picus auratus, 411; pieus major, 456. 
 
 Pieris, 354, 361. 
 
 Pigeon, female, deserting a weakened mate, 243; carrier, late 
 development of the wattle in, 269; pouter, late development of the 
 crop in, 269; domestic, breeds and sub-breeds of, 523. 
 
 Pigeons, nestling, fed by the secretion of the crop of both parents, 
 185; changes of plumage in, 259; transmission of sexual peculiarities 
 in, 261; Belgian, with black-streaked males, 262, 269, 507; changing 
 color after several moul tings, 269; numerical proportion of the sexes 
 in, 280; cooing of, 425; variations in plumage of, 438; display of 
 plumage by male, 456; local memory of, 467; antipathy of female, 
 to certain males, 475; pairing of, 475; profligate male and female, 
 475; wing-bars and tail-feathers of, 486; supposititious breed of, 506; 
 pouter and carrier, peculiarities of, predominant in males, 508; nidifi- 
 cation of, 516; Australian, 522; immature plumage of the, 532. 
 
 Pigs, origin of the improved breeds of, 202; numerical proportion 
 of the sexes in, 279; stripes of young, 529, 623; tusks of miocene, 
 693; sexual preference shown by, 598. 
 
 Pike, American, brilliant colors of the male, during the breeding'
 
 774 INDEX. 
 
 seasons. C86; reasoning powers of, 85; male, devoured l>y females, 
 281. 
 
 Pike, L. O., OB the psychical elements of religion, 108. 
 
 Pimelia striata, sounds produced by the female, 347. 
 
 Pinel, hairiness in idiots, 41. 
 
 Pintail, drake, plumage of, 446; pairing with a wild duck, 471; 
 duck, pairing with a widgeon, 471. 
 
 Pipe-fish, filamentous, 390; marsupial receptacles of the male, 392. 
 
 Pipits, moulting of the, 444. 
 
 Pipra, modified secondary wing-feathers of the male, 429; pipra 
 deliciosa, 429, 430. 
 
 Pirates stridulus, stridulation of, 319. 
 
 Pitcairn Island, half-breeds on, 217. 
 
 Pithecia leucocephala, sexual differences of color in, 613; pithecia 
 satanas, beard of, 607; resemblance of, to a negro, 690. 
 
 Pits, suborbital, of Ruminants, 604. 
 
 Pittidse, nidification of, 516. 
 
 Placentata, 179. 
 
 Plagiostomous fishes, 375. 
 
 Plain-wanderer, Australian, 542. 
 
 Planaria, bright colors of some, 295. 
 
 Plantain-eaters, colors and nidificatioa of the, 518; both sexes of, 
 equally brilliant, 523. 
 
 Plants, cultivated, more fertile than wild, 50; Nageli, on natural 
 selection in, 68; male flowers of, mature before the female, 240; 
 phenomena of fertilization in, 251. 
 
 Platalea, 425, change of plumage in, 525. 
 
 Platyblemnus, 328. 
 
 Platycercus, young of, 549. 
 
 Platyphyllum concavum, 321, 324. 
 
 Platyrrhine monkeys, 174. 
 
 Plntysma myoides, 14. 
 
 Plecostomus, head-tentacles of the males of a species of, 384; 
 plecostomus barbatus, peculiar beard of the male, 383. 
 
 Plectropterus gambcnsds, spurred wings of, 414. 
 
 Ploceus, 420, 426, 460. 
 
 Plovers, wing-spurs of, 414; double moult in, 442, 444. 
 
 Plumage, changes of, inheritance of, by fowls, 259; tendency t* 
 analogous variation in, 438; display of, by male birds, 447, 455; 
 changes of, in relation to season, 526; immature, of birds, 529, 530; 
 color of, in relation to protection, 556. 
 
 Plumes on the head in birds, differences of, in the sexes, 513. 
 
 Pneumora, structure of, 325. 
 
 Podica, sexual difference in the color of the irides of, 483. 
 
 Poeppig, on the contact of civilized and savage races, 208. 
 
 Poison, avoidance of, by animals, 90. 
 
 Poisonous fruits and herbs avoided by animals, 75. 
 
 Poisons, immunity from, correlated with color, 220. 
 
 Polish fowls, origin of the crest in, 261. 
 
 Pollen and van Dam, on the colors of Lemur macaco, 613. 
 
 Polyandry, 677; in certain Cyprinidte, 282; among the Elateridw, 
 286. 
 
 Polydactylisrn in man, 42,
 
 INDEX. 775 
 
 Polygamy, influence of, upon sexual selection, 245; superinduced 
 by domestication, 249; supposed increase of female births by, 277; in 
 the stickleback, 376. 
 
 Polygenists, 200. 
 
 Polynesia, prevalence of infanticide in, 676. 
 
 Polynesians, wide geographical range of, 38; difference of stature 
 among the, 35; crosses of, 198; variability of, 198; heterogeneity of 
 the, 219; aversion of, to hairs on the face, 662. 
 
 Polyplectron, number of spurs in, 413; display of plumage by tht> 
 male, 450; gradation of characters in, 490; female of, 536; polyplect- 
 ron chinquis, 450, 491 ; polyplectron hardwickii, 491 ; polyplectron 
 malaccense, 491, 492. 
 
 Polyplectron Napoleonis, 490, 492. 
 
 Polyzoa, 296. 
 
 Pomotis, 391. 
 
 Pontoporeia affinis, 300. 
 
 Porcupine, mute, except in the rutting- season, 600. 
 
 Pores, excretory, numerical relation of, to the hairs in sheep, 225. 
 
 PorpitcB, bright colors of some, 295. 
 
 Portax picta, dorsal crest and throat-tuft of, 606; sexual differences 
 of color in, 611, 612, 621. 
 
 Portunus puber, pugnacity of, 304. 
 
 Potamochcerus penicillatus, tusks and facial knobs of the, 593. 
 
 Pouchet G., the relation of instinct to intelligence, 75; on the 
 instincts of ants, 168; on the caves of Abou-Simbel, 191; on the 
 immunity of negroes from yellow fever, 220; change of color in 
 fishes, 390. 
 
 Pouter-pigeon, late development of the large crop in, 269. 
 
 Powell, Dr., on stridulation, 319. 
 
 Power, Dr., on the different colors of the sexes in a species of 
 Squilla, 306. 
 
 Powys, Mr., on the habits of the chaffinch in Corfu, 281. 
 
 Pre-eminence of man, 54. 
 
 Preference for males by female birds, 470, 477; shown by mammals, 
 in pairing, 595. 
 
 Prehensile organs, 237. 
 
 Presbytis entellus, fighting of the male, 641. 
 
 Preyer, Dr., on function of shell of ear, 15; on supernumerary 
 mammae in women, 41. 
 
 Prichard, on the difference of stature among the Polynesians, 35; 
 on the connection between the breadth of the skull in the Mongolians 
 and the perfection of their senses, 38; on the capacity of BritisG. 
 skulls of different ages, 61; on the flattened heads of the Colombian 
 savages, 655; on Siamese notions of beauty, 659; on the beardlessness 
 of the Siamese, 663; on the deformation of the head among American 
 tribes and the natives of Arakhan, 665. 
 
 Primary sexual organs, 234. 
 
 Primates, 170, 283; sexual differences of color in, 613. 
 
 Primogeniture, evils of, 153. 
 
 Prionidae, difference of the sexes in color, 333. 
 
 Proctotretus multimaculatus, 406; proctotretus t&nuis, sexual differ* 
 ence in the color of, 406. 
 
 Profligacy, 155.
 
 776 INDEX. 
 
 Progenitors, early, of man, 182. 
 
 Progress, not the normal rule in human society, 150; elements 
 of, 159. 
 
 Prong-horn antelope, horns of, 265. 
 
 Proportions, difference of, in distinct races, 190. 
 
 Protective coloring in butterflies, 353; in lizards, 406; in birds, 
 539, 556; in mammals, 619; nature of the dull coloring of female 
 Lepidoptera, 363, 364, 367; resemblances in fishes, 390. 
 
 Protozoa, absence of secondary sexual characters in, 294. 
 
 Pruner-Bey, on the occurrence of the supra- condyloid foramen in 
 the humerus of man, 24; on the color of negro infants, 636. 
 
 Prussia, numerical proportion of male and female births in, 275. 
 
 Psocus, proportions of the sexes in, 287. 
 
 Ptarmigan, monogamous, 248; summer and winter plumage of the, 
 443, 444; nuptial assemblages of, 460; triple moult of the, 526; pro- 
 tective coloration of, 540. 
 
 Puff-birds, colors and nidification of the, 518. 
 
 Pugnacity of fine-plumaged male birds, 454. 
 
 Pumas, stripes of young, 528. 
 
 Puppies learning from cats to clean their faces, 82. 
 
 Pycnonotus Iwmorrhous, pugnacity of the male, 409; display of 
 under tail coverts by the male, 456. 
 
 Pyranga (estiva, male aiding in incubation, 515; male characters in 
 female of, 525. 
 . Pyrodes, difference of the sexes in color, 333. 
 
 Quadrumaua, hands of, 56; differences between man and the, 170; 
 sexual differences of color in, 612; ornamental characters of, 626; 
 analogy of sexual differences of, with those of man, 634; fighting of 
 males for the females, 641; monogamous habits of, 674; beards of 
 the, 688. 
 
 Quain, R., on the variation of the muscles in man, 30. 
 
 Quatrefages, A. de, on the occurrence of a rudimentary tail in man, 
 25; on variability, 33; on the moral sense as a distinction between 
 man and animals, 110; civilized men stronger than savages, 154; on 
 the fertility of Australian women with white men, 194 ; on the 
 Paulistas of Brazil, 197; on the evolution of the breeds of cattle, 
 201; on the Jews, 220; on the liability of negroes to tropical fevers 
 after residence in a cold climate, 221 ; on the difference between 
 field and house slaves, 223; on the influence of climate on color, 223; 
 colors of annelids, 299; on the Ainos, 639; on the women of San 
 Uiuliano, 670. 
 
 Quechua, see Quichua. 
 
 Querquedula acuta, 471. 
 
 Quetelet, proportion of sexes in man, 275; relative size in man and 
 woman, 276. 
 
 Quichua Indians, 38; local variation of color in the, 223; no gray 
 hair among the, 637; hairlessness of the, 640; long hair of the, 662. 
 
 Quiscalus major, 255; proportion of the sexes of, in Florida and 
 Honduras, 281. 
 
 Rabbit, white tail of the, 619. 
 
 Rabbits, domestic, elongation of the skull in, 63; modification of 
 the skull in, by the lopping of the cnr, 63; danger-signals of, 114; 
 numerical proportion of tjje aexes in. 279
 
 INDEX. 777 
 
 Races, distinctive characters of, 190, 191; or species of man, 191; 
 crossed, fertility or sterility of, 194; of man, variability of tlie, 198; 
 of man, resemblance of, in mental characters, 203; formation of, 206; 
 of man, extinction of, 206; effects of the crossing of, 218; of man, 
 formation of the, 218; of man, children of the, 635; beardless, aver- 
 sion of, to hairs on the face, 662. 
 
 Raffles, Sir S., on the banteng, 613. 
 
 Rafts, use of, 54, 205. 
 
 Rage, manifested by animals, 77. 
 
 Raia bat is, teeth of, 379; raid clavata, female spined on the back, 
 375; sexual difference in the teeth of, 379; raia maculata, teeth of, 
 379. 
 
 RaiU\, spur- winged, 414. 
 
 Rain, mode of fighting of the, 579; African, mane of an, 608; fat- 
 tailed, 608. 
 
 Rameses II, features of, 192. 
 
 Ramsay, Mr., on the Australian muck-duck, 407; on the regent- 
 bird, 470; on the incubation of Menura superba, 513. 
 
 Sana esculenta, vocal sacs of, 397. 
 
 Rat, common, general dispersion of, a consequence of superior 
 cunning, 91; supplantation of the native, in New Zealand, by the 
 European rat, 218; common, said to be polygamous, 247; numerical 
 proportion of the sexes in, 279. 
 
 Rats, enticed by essential oils, 603. 
 
 Rationality of birds, 466. 
 
 Rattlesnakes, difference of the sexes in the, 398; rattles as a 
 call, 401. 
 
 Raven, vocal organs of the, 421; stealing bright objects, 469; pied, 
 of the Feroe Islands, 482. 
 
 Rays, prehensile organs of male, 375. 
 
 Razor-bill, young of the, 553. 
 
 Reade, Win wood, suicide among savages in Africa, 133; mulattoes 
 not prolific, 195; effect of castration of horned sheep, 577; on the 
 Guinea sheep, 266; on the occurrence of a mane in an African ram, 
 608; on singing of negroes, 652; on the negroes appreciation of the 
 beauty of their women, 658; on the admiration of negroes for a 
 black skin, 660; on the idea of beauty among negroes, 663; on the 
 Jollofs, 670; on the marriage-customs of the negroes, 684. 
 
 Reason in animals, 84. 
 
 Redstart, American, breeding in immature plumage, 552. 
 
 Redstarts, new mates found by, 464. 
 
 Reduvidse, stridulation of, 319. 
 
 Reed-bunting, head-feathers of the male, 455; attacked by a bull- 
 finch, 468. 
 
 Reefs, fishes frequenting, 389. 
 
 Reeks, H., retention of horns by breeding deer, 574; cow rejected 
 by a bull, 598; destruction of piebald rabbits by cats, 619. 
 
 Regeneration, partial, of lost parts in man, 8. 
 
 Regent-birds, 470. 
 
 Reindeer, horns of the, 264; battles of, 571; horns of the female, 
 574; antlers of, with numerous points, 582; winter change of the, 
 619; sexual preferences shown by, 598. 
 
 Relationship, terms of, 675.
 
 778 INDEX. 
 
 Religion, deficiency of among certain races, 106; psychical elements 
 of, 107. 
 
 Remorse, 129; deficiency of, among savages, 149. 
 
 Rengger, on the diseases of Cebus Azar&, 7; on the diversity of 
 the mental faculties of msnkeys. 31; on the Payaguas Indians, 37; 
 on the inferiority of Europeans to savages in their senses, 38; revenge 
 taken by monkeys, 78; on maternal affection in a Cebus, 79; on the 
 reasoning powers of American monkeys, 87; on the use of stones by 
 monkeys for cracking hard nuts, 91; on the sounds uttered by Ctbus 
 Azarai, 95; on the signal-cries of monkeys, 98; on the polygamous 
 habits of Mycetes car ay a, 246; on the voice of the howling monkeys, 
 602; on the odor of Cermis campestris, 604; on the beards of Mycetes 
 caraya and Pithecia Satanas, 607; on the colors of Felis mitis, 610; 
 on the colors of Cervus paludous, 613; on sexual differences of color 
 in Mycetes, 613; on the color of the infant Guaranys, 636; on the 
 early maturity of the female of Cebes Azara, 636; on the beards' of the 
 Guaranys, 639; on the emotional notes employed by monkeys, 652; 
 on American polygamous monkeys, 674. 
 
 Representative species, of birds, 533. 
 
 Reproduction, unity of phenomena of, throughout the mammalia, 
 8; period of, in birds, 551. 
 
 Reproductive system, rudimentary structures in the, 26; accessory 
 parts of, 183. 
 
 Reptiles, 397. 
 
 Reptiles and birds, alliance of, 188. 
 
 Resemblances, small, between man and the apes, 171. 
 
 Retrievers, exercise of reasoning faculties by, 88. 
 
 Revenge, manifested by animals, 78. 
 
 Reversion, 41; perhaps the cause of some bad dispositions, 155. 
 
 Rhagium, difference of color in the sexes of a species of, 833. 
 
 Rhamphastos cannatus, 560. 
 
 Rhea Daricinii, 545. 
 
 Rhinoceros, nakedness of, 64; horns of, 576; horns of, used defens- 
 ively, 590; attacking white or gray horses, 617. 
 
 Rhyncluw, sexes and young of, 543; rhyncJicea amtralis, 543; 
 rhynchcea bengalensis, 543; rhynch&a capensis, 543. 
 
 Rhythm, perception of, by animals, 649. 
 
 Richard, M., on rudimentary muscles in man, 13. 
 
 Richard, Sir J., on the pairing of Tetrao umbellus, 416; on Tetrao 
 urophasianus, 423; on the drumming of grouse, 423, 427; on the 
 dances of Tetrao phasianellus, 431; on assemblages of grouse, 460; 
 on the battles of male deer, 571; on the reindeer, 574; on the horns 
 of the musk-ox, 576 ; on antlers of the reindeer with numerous 
 points, 582; on the moose, 587; on the Scotch deerhound, 589. 
 
 Richter, Jean Paul, on imagination, 84. 
 
 Riedel, on profligate female pigeons, 475. 
 
 Riley, Mr., on mimicry in butterflies, 367; bird's disgust at taste of 
 certain caterpillars, 370. 
 
 Ring-ouzel, colors and nidification of the, 518. 
 
 Ripa, Father, on the difficulty of distinguishing the races of the 
 Chinese, 190. 
 
 Rivalry, in singing, between male birds, 419. 
 
 River-hog, African, tusks and knobs of the, 598.
 
 INDEX. 779 
 
 Rivers, analogy of, to islands, 181. 
 
 Roach, brightness of the male during breeding-season, 886. 
 
 Robbery, of strangers, considered honorable, 133. 
 
 Robertson, Mr. , remarks on the development of the horns in the 
 roebuck and red-deer, 265. 
 
 Robin, pugnacity of the male, 408; autumn song of the, 420; 
 female singing of the, 420; attacking other birds with red in their 
 plumage, 408; young of the, 547. 
 
 Kobinet, on the difference of size of the male and female cocoons 
 of the silk-moth, 315. 
 
 Rodents, uterus in the, 43; absence of secondary sexual characters 
 in, 247; sexual differences in the colors of, 609. 
 
 Roe, winter changes of the, 619. 
 
 Rohfs, Dr., Caucasian features in negro, 190; fertility of mixed 
 races in Sahara, 195; colors of birds in Sahara, 557; ideas of beauty 
 among the Bornuans, 663. 
 
 Rolle, F., on the origin of man, 3; on a change in German families 
 settled in Georgia, 223. 
 
 Roller, harsh cry of, 421. 
 
 Romans, ancient, gladiatorial exhibitions of the, 139. 
 
 Rook, voice of the, 426. 
 
 Rossler, Dr. , on the resemblance of the lower surface of butterflies 
 to the bark of trees, 353. 
 
 Rostrum, sexual difference in the length of, in some weevils, 235. 
 
 Royer, Madlle., mammals giving suck, 186. 
 
 Rudimentary organs, 12; origin of, 26. 
 
 Rudiments, presence of, in languages, 102. 
 
 Rudolphi, on the want of connection between climate and the color 
 of the skin, 219. 
 
 Ruff, supposed to be polygamous, 248; proportion of the sexes in 
 the, 280; pugnacity of the, 409; double moult in, 443, 445; duration 
 of dances of, 460; attraction of the, to bright objects, 469. 
 
 Ruminants, male, disappearance of canine teeth in, 60, 641 ; 
 generally polygamous, 246; suborbital pits of, 604; sexual differences 
 of color in, 611. 
 
 Rupicola crocea, display of plumage by the male, 448. 
 
 Ruppell, on canine teeth in deer and antelopes, 586. 
 
 Russia, numerical proportion of male and female births in, 
 ' 243, 275. 
 
 Euticilla, 525. 
 
 Rutmeyer, Prof., on the physiognomy of the apes, 60; on tusks of 
 miocene boar, 593; on the sexual differences of monkeys, 640. 
 
 Rutlandshire, numerical proportion of male and female births 
 in, 274. 
 
 Sachs, Prof., on the behavior of the male and female elements in 
 fertilization, 252. 
 
 Sacrifices, human, 108. 
 
 Sagittal crest in male apes and Australians, 636. 
 
 Sahara, fertility of mixed races in, 195; birds of the, 519; animal 
 inhabitants of the, 557. 
 
 Sailors, growth of, delayed by conditions of life, 34 ; long- 
 sighted, 38. 
 
 Sailors and soldiers, difference in the proportions of, 36.
 
 780 INDEX. 
 
 St. John, Mr. , on the attachment of mated birds, 466. 
 
 St. Kilda, beards of the inhabitants of, 638. 
 
 Salmo eriox and 8. umbla, coloring of the male, during the breed, 
 ing-season, 886. 
 
 Salmo lycaodon, 378; salmo solar, 377. 
 
 Salmon, leaping out of fresh water, 122; male, ready to breed 
 before the female, 240; proportion of the sexes in, 282; male, pug- 
 nacity of the, 377; male, characters of, during the breeding-season, 
 377, 386; spawning of the, 390; breeding of immature male, 552. 
 
 Salvin, 0., inheritance of mutilated feathers, 67, 436, 689; on the 
 humming-birds, 248, 516; on the numerical proportion of the sexes 
 in humming-birds, 281, 555; on Chamcrpetes and Penelope, 429; on 
 Selasphorus platycercus, 429; Pipra deliciosa, 429; on Chasmorhyn- 
 chus, 442. 
 
 Samoa Islands, beardlessness of the natives of, 639, 663. 
 
 Sandhoppers, claspers of male, 307. 
 
 Sand-skipper, 305. 
 
 Sandwich Islands, variation in the skulls of the natives of the, 29; 
 decrease of native population, 211; population of, 290; superiority of 
 the nobles in the, 669; Islanders, lice of, 193. 
 
 San-Giuliano, women of, 670. 
 
 Santali, recent rapid increase of the, 51; Mr. Hunter on the, 218. 
 
 Saphirina, characters of the males of, 306. 
 
 Sarkidiornis melanonotus, characters of the young, 529. 
 
 Sars, O., on Pontoporeia affinis, 300. 
 
 Saturnia carpini, attraction of males by the female, 284; saturnia 
 <j, difference of coloration in the sexes of, 358. 
 
 Saturniidce, coloration of the, 356, 858. 
 
 Savage, Dr., on the fighting of the male gorillas, 641; on the habits 
 of the gorilla, 675. 
 
 Savage and Wyinan on the polygamous habits of the gorilla, 246. 
 
 Savages, uniformity of, exaggerated, 32; long-sighted, 37; rate of 
 increase among, usually small, 50; retention of the prehensile power 
 of the feet by, 58; imitative faculties of, 98, 146; causes of low 
 morality of, 135; tribes of, supplanting one another, 145; improve- 
 ments in the arts among, 164; arts o^, 203; fondness of, for rough 
 music, 431; on long-enduring fashions among, 563; attention paid 
 by, to personal appearance, 654; relation of the sexes among, 675. 
 
 Saviotti, Dr., division of malar bone, 44. 
 
 Saw-fly, pugnacity of a male, 330. 
 
 Saw-flies, proportions of the sexes in, 286. 
 
 Baxicola rubicola, young of, 555. 
 
 Scalp, motion of the, 14. 
 
 Scent-glands in snakes, 399. 
 
 Schaaffhausen, Prof., on the development of the posterior molars 
 in different races of man, 22; on the jaw from La Naulette, 46; on 
 the correlation between muscularity and prominent supraorbital 
 ridges, 49; on the mastoid processes of man, 59; on modifications of 
 the cranial bones, 62; on human sacrifices, 163; on the probable 
 speedy extermination of the anthropomorphous apes, 178; on the 
 ancient inhabitants of Europe, 207; on the effects of use and disuse 
 of parts, 225; on the superciliary ridge in man, 634; on the absence 
 of race -differences in the infant skull in man, 635; on ugliness, 666.
 
 INDEX. 781 
 
 Schaum, H., on the elytra of Dytiscus and Hydroporus, 313. 
 
 Scherzer and Schwarz, measurements of savages, 638. 
 
 Schelver, on dragon-Hies, 329. 
 
 Schiodte, on the stridulation of Heterocerus, 343. 
 
 Schlegel, F. von, on the complexity of the languages of uncivilised 
 peoples, 103. 
 
 Schlegel, Prof., on Tanysiptera, 533. 
 
 Schleicher, Prof., on the origin of language, 98. 
 
 Schomburgk, Sir R., on the pugnacity of the male musk-duck of 
 Guiana, 411; on the courtship of Rupicola crocea, 448. 
 
 Schoolcraft, Mr., on the difficulty of fashioning stone imple- 
 ments, 55. 
 
 Schopenhauer, on importance of courtship to mankind, 669. 
 
 Schweinf urth, complexion of negroes, 634. 
 
 Scicena aquila, 394. 
 
 Sclater, P. L. , on modified secondary wing-feathers in the males of 
 Pipra, 429, 430 ; on elongated feathers in nightjars, 436 ; on the 
 species of Ghasmorhynchus, 442; on the plumage of Pelecanus 
 onocrotalus, 446; on the plantain-eaters, 523; on the sexes and young 
 of Tadorna vanegata, 546; on the colors of Lemur macaco, 613; on 
 the stripes in asses, 626. 
 
 Scolecida, absence of secondary sexual characters in, 294. 
 
 Scolopax frenata, tail - feathers of, 428; scolopax gallinago, 
 drumming of, 427; scolopax javensis, tail-feathers of, 428; scolopax 
 major, assemblies of, 460; scolopax wilsonii, sound produced by, 428. 
 
 Scolytus, stridulation of, 342. 
 
 Scoter-duck, black, sexual difference in coloration of the, 559, 
 bright beak of male, 559. 
 
 Scott, Dr., on idiots smelling their food, 41. 
 
 Scott, J., on the color of the beard in man, 637. 
 
 Scrope, on the pugnacity of the male salmon, 377; on the battles 
 of stags, 571. 
 
 Scudder, S. H., imitation of the stridulation of the Orthoptera, 
 321; on the stridulation of the Acridiidae, 324; on a Devonian insect, 
 327; on stridulation, 646. 
 
 Sculpture, expression of the ideal of beauty by, 663. 
 
 Sea-anemones, bright colors of, 294. 
 
 Sea-bear, polygamous, 247. 
 
 Sea-elephant, male, structure af the nose of the, 603; polygamous, 
 247. 
 
 Sea-lion, polygamous, 247. 
 
 Seal, bladder-nose, 603. 
 
 Seals, their sentinels generally females, 114; evidence furnished 
 
 , on classification, 170; polygamous habits of, 247; battles of male, 
 le, 572; 
 
 570; canine teeth of male, 572; sexual differences, 588 ; pairing of, 
 696; sexual peculiarities of, 603; in the coloration of, 610; apprecia- 
 tion of music by, 649. 
 
 Sea-scorpion, sexual differences in, 381. 
 
 Season, changes of color in birds, in accordance with the, 442; 
 changes of plumage of birds in relation to, 526. 
 
 Seasons, inheritance at corresponding, 259. 
 
 Sebituani, African chief, trying to alter a fashion, 656. 
 
 Sebright Bantam, 270.
 
 783 INDEX. 
 
 Secondary sexual characters, 234; relations of polygamy to, 245, 
 transmitted through both sexes, 255; gradation of, in "birds, 488. 
 
 Sedgwick, W., on hereditary tendency to produce twins, 51. 
 
 Seemann, Dr., on the different appreciation of music by different 
 peoples, 650; on the effects of music, 651. 
 
 Seidlitz, on horns of reindeer, 577. 
 
 Selasp7ioriis platycercus, acuminate first primary of the male, 429. 
 
 Selby, P. J., on the habits of the black and red grouse, 248. 
 
 Selection, as applied to primeval man, 32; double, 255; injurious 
 forms of, in civilized nations, 152; of male by female birds, 459, 477; 
 methodical, of Prussian grenadiers, 32; sexual, explanation of, 236, 
 241, 249; influence of, on the coloring of Lepidoptera, 363; sexual 
 and natural, contrasted, 256. 
 
 Self-command, habit of, inherited, 181; estimation of, 134. 
 
 Self -consciousness, in animals, 93. 
 
 Self-preservation, instinct of, 127. 
 
 Self -sacrifice, by savages, 126; estimation of, 134. 
 
 Semilunar fold, 19. 
 
 Semnopithecus, 175; long hair on the heads of species of, 171, 
 689; semnopithecus chrysomelas, sexual differences of color in, 614; 
 semnopitftecus comatus, ornamental hair on the head of, 627; semnopi- 
 thecus frontatus, beard, etc., of, 629; semnopithecus nasica, nose of, 
 171; semnopithecus nemceus, coloring of , 629; semnopithecus rubicun- 
 dus, ornamental hair on the head of, 625. 
 
 Senses, inferiority of Europeans to savages in the, 88. 
 
 Sentinels, among animals, 114, 121. 
 
 Serpents, instinctively dreaded by apes and monkeys, 75, 80. 
 
 Serranus, hermaphroditism in, 184. 
 
 Setina, noise produced by, 849. 
 
 Sex, inheritance limited by, 260. 
 
 Sexes, relative proportions of, in man, 274, 636; proportions of, 
 sometimes influenced by selection, 288; probable relation of the, in 
 primeval man, 674. 
 
 Sexual and natural selection, contrasted, 256; characters, effects of 
 the loss of, 261; limitation of, 262; characters, secondary, 234; rela- 
 tions of polygamy to, 245; transmitted through both sexes, 255; 
 gradation of, in birds, 488. 
 
 Sexual differences in man, 8; selection, explanation of, 236, 241, 
 249; influence of, on the coloring of Lepidoptera, 363; objections to, 
 563; action of, in mankind, 679; selection in spiders, 807; selection, 
 supplemental note on, 709; similarity, 288. 
 
 Shaler, Prof., sizes of sexes in whales, 688. 
 
 Shame, 129. 
 
 Sharks, prehensile organs of male, 375. 
 Sharpe, Dr., Europeans in thi 
 
 the tropics, 222. 
 
 Sharpe, R. B., on Tanysiptera sylvia, 514; on Ceryle, 620; on the 
 young male of JDacflo Gaudichaudi, 532. 
 
 Shaw, Mr., on the pugnacity of the male Salmon, 877. 
 
 Shaw, J., on the decorations of birds, 434. 
 
 Sheep, danger-signals of, 114; sexual differences in the horns of, 
 260; horns of, 266, 576; domestic, sexual differences of, late devel- 
 oped, 269; numerical proportion of the sexes in, 279; inheritance of 
 horns by one sex, 576; effect of castration, 577; mode of lighting of,
 
 INDEX. 783 
 
 579; arched foreheads of some, 608; merino, loss of horns in females 
 of, 261 ; horns of, 266. 
 
 Shells, difference in form of, in male and female Gasteropoda, 297; 
 beautiful colors and shapes of, 298. 
 
 Shield-drake, pairing with a common duck, 471; New Zealand, 
 sexes and young of, 546. 
 
 Shooter, J., on the Kaffirs, 661; on the marriage-customs of the 
 Kaffirs, 661. 
 
 Shrew-mice, odor of, 604. 
 
 Shrike, Drongo, 524. 
 
 Shrikes, characters of young, 529. 
 
 Shuckard, W. E., on sexual differences in the wings of Hymenop- 
 tera, 314. 
 
 Shyness of adorned male birds, 457. 
 
 Siagonium, proportions of the sexes in, 286; dimorphism in males 
 of, 339. 
 
 Siam, proportion of male and female births in, 277. 
 
 Siamese, general beardlessness of the, 639; notions of beauty of 
 the, 660; hairy family of , 687. 
 
 Sidgwick, H., on morality in hypothetical bee community, 113; our 
 actions not entirely directed by pain and pleasure, 136. 
 
 Siebold, C. T. von, on the proportion of sexes in the Apus, 287; on 
 the auditory apparatus of the stridulant Orthoptera, 321. 
 
 Sight, inheritance of long and short, 38. 
 
 Signal -cries of monkeys, 98. 
 
 Silk-moth, proportion of the sexes in, 282, 284; A'ilanthus, Prof. 
 Canestrini, on the destruction of its larvae by wasps, 284; difference 
 of size of the male and female cocoons of the, 315; pairing of 
 the, 360. 
 
 Simiadae, 173; their origin and divisions, 188. 
 
 Similarity, sexual, 254. 
 
 Singing, of the Cicadae and Fulgoridae, 319; of tree-frogs, 397; of 
 birds, object of the, 417. 
 
 Sirenia, nakedness of, 63. 
 
 Sircx juvencus, 331. 
 
 Siricidse, difference of the sexes in, 331. 
 
 Siskin, 446; pairing with a canary, 472. 
 
 Sitana, throat-pouch of the males of, 402, 406. 
 
 Size, relative, of the sexes of insects, 315. 
 
 Skin, dark color of, a protection against heat, 223. 
 
 Skin, movement of the, 14; nakedness of, in man, 63; color of 
 the, 219; and hair, correlation of color of, 225. 
 
 Skull, variation of, in man, 29; cubic contents of, no absolute test 
 of intellect, 61; Neanderthal, capacity of the, 61; causes of modifica- 
 tion of the, 62; difference of, in form and capacity, in different races 
 of men, 192; variability of the shape of the, 198; differences of, in 
 the sexes in man, 635; artificial modification of the shape of, 655. 
 
 Skunk, odor emitted by the, 603; white tail of, protective, 621. 
 
 Slavery, prevalence of, 133; of women, 677. 
 
 Slaves, difference between field and house-slaves, 224. 
 
 Sloth, ornaments of male, 610. 
 
 Smell, sense of, in man and animals, 19. 
 
 Smith, Adam, on the basis of sympathy, 120.
 
 784 INDEX. 
 
 Smith, Sir A., on the recognition of women by male Cynocephali, 
 9; on revenge by a baboon, 78; on an instance of memory in a 
 baboon, 83; on the retention of their color by the Dutch in South 
 Africa, 219; on the polygamy of the South African antelopes, 246; 
 on the polygamy of the lion, 247; on the proportion of the sexes in, 
 Kobus ettipsiprymnus, 279; on Bucephalus capensis, 398; on South 
 African lizard?, 406; on fighting gnus, 571; on the horns of rhinoce- 
 roses, 576; on the fighting of lions, 594; on the colors of the Cape 
 eland, 612; on the colors of the gnu, 612; on the Hottentot notions 
 of beauty, 660; disbelief in communistic marriages, 671. 
 
 Smith, F., on the Cynipidae and Tenthredinidae, 286; on the rela- 
 tive size of the sexes of Aculeate Hymenopetra, 316; on the difference 
 between the sexes of ants and bees, 331; on the stridulation of Trox 
 sabulosus, 343; on the stridulation of Mononychus pseudacori, 345. 
 
 Smynthurus luteus, courtship of, 317. 
 
 Snakes, sexual differences of, 398; mental powers of, 399; male, 
 ardency of, 399. 
 
 " Snarling muscles," 46. 
 
 Snipe, drumming of the, 427; coloration of the, 558; painted, 
 sexes and young of, 542; solitary, assemblies of, 461. 
 
 Snipes, arrival of male before the female, 240; pugnacity of male, 
 411; double moult in, 442. 
 
 Snow-goose, whiteness of the, 560. 
 
 Sociability, the sense of duty connected with, 111; impulse to, in 
 animals, 119; manifestations of, in man, 123; instinct of, hi ani- 
 mals, 124. 
 
 Social animals, affection of, for each other, 115, defense of, by the 
 males, 121. 
 
 Sociality, probable, of primeval men, 70; influence of, on the de- 
 velopment of the intellectual faculties, 146; origin of, in man, 147. 
 
 Soldiers, American, measurements of, 34; and sailors, difference in 
 the proportions of, 36. 
 
 Solenostoma, bright colors and marsupial sac of the females 
 of, 393. 
 
 Song, of male birds appreciated by their females, 104; want of, in 
 brilliant plumaged birds, 454; of birds, 512. 
 
 S<n-ex, odor of, 603. 
 
 Sounds, admired alike by man and animals, 104; produced by 
 fishes, 393; produced by male frogs and toads, 397; instrumentally 
 produced by birds, 426 et seq. 
 
 Spain decadence of, 160. 
 
 Sparassus smaragdulus, difference of color in the sexes of, 307. 
 
 Sparrow, pugnacity of the male, 409; acquisition of the linnet's 
 song by a, 420; coloration of the, 539; immature plumage of the, 
 532; white-crowned, young of the, 553. 
 
 Sparrows, house and tree, 518, 550; new mates found by, 463; 
 sexes and young of, 550; learning to sing, 651. 
 
 Spathura Undencoodi, 440. 
 
 Spawning of fishes, 387, 391. 
 ^Spear, used before dispersion of man, 204. 
 
 Species, causes of the advancement of, 156; distinctive characters 
 of, 190; or races of man, 191; sterility and fertility of, when 
 crossed, 194; supposed, of man. 198; gradation of, 198; "difficulty of
 
 INDEX. 785 
 
 defining, 199; representative, of birds, 533; of birds, comparative 
 differences between the sexes of distinct, 534. 
 
 Spectrum femoratum, difference of color in the sexes of. 328. 
 
 Speech, connection between the brain and the faculty of, 99; con- 
 nection of intonation with music, 653. 
 
 " Spel " of the black-cock, 425. 
 
 Spencer, Herbert, on the influence of food on the size of the jaws, 
 37; on the dawn of intelligence, 75; on the origin of the belief in 
 spiritual agencies, 106; on the origin of the moral sense, 139; on 
 music, 652, 653. 
 
 Spengel, disagrees with explanation of man's hairlessness, 687. 
 
 Sperm-whales, battles of male, 570. 
 
 Sphingidae, coloration of the, 356. 
 
 Sphinx, humming-bird, 359; Mr. Bates on the caterpillar of a, 369. 
 
 Sphinx moth, musky odor of, 349. 
 
 Spiders, 307; parental feeling in, 120; male, more active than 
 female, 250; proportion of the sexes in, 287; secondary sexual char- 
 acters of, 308; courtship of male, 308; attracted by music, 309; male, 
 small size of, 308. 
 
 Spilosoma menthastri, rejected by turkeys, 358. 
 
 Spine, alteration of, to suit the erect attitude of man, 59. 
 
 Spirits, fondness of monkeys for, 7. 
 
 Spiritual agencies, belief in, almost universal, 106. 
 
 Spiza cyanea and ciris, 468. 
 
 Spoonbill, 425; Chinese, change of plumage in, 525. 
 
 Spots, retained throughout groups of birds, 485; disappearance of, 
 in adult mammals, 623. 
 
 Sprengel, C. K., on the sexuality of plants, 240. 
 
 Spring-boc, horns of the, 580. 
 
 Sproat, Mr., on the extinction of savages in Vancouver Island, 208; 
 on the eradication of facial hair by the natives of Vancouver Island, 
 662; on the eradication of the beard by the Indians of Vancouver 
 Island, 689. 
 
 Spurs, occurrence of, in female fowls, 257, 261; development of, 
 in various species of Phasianidae, 267; of Gallinaceous birds, 412, 
 413; development of, in female Gallinaceae, 511. 
 
 Squitta, different colors of the sexes of a species of, 306. 
 
 Squirrels, battles of male, 570; African, sexual differences in the 
 coloring of, 609; black, 616. 
 
 Stag, long hairs of the throat of, 595; horns of the, 257, 260; 
 battles of, 571; horns of the, with numerous branches, 581; bellow, 
 ing of the, 601; crest of the, 606; beetle, numerical proportion of 
 sexes of, 286; use of jaws, 312; large size of male, 316; weapons of 
 the male, 339. 
 
 Stainton, H. T., on the numerical proportion of the sexes in th 
 smaller moths, 283; habits of Elachista rufocinerea, 284 ; on tha 
 coloration of moths, 357; on the rejection of Spilosoma menthastri by 
 turkeys, 358; on the sexes of Agrotis exclamationis, 358. 
 
 Staley, Bishop, mortality of infant Maories, 213. 
 
 Stallion, mane of the, 594. 
 
 Stallions, two, attacking a third, 115; fighting, 571; small canine 
 teeth of, 586. 
 
 Stansbury, Capt., observations on pelicans, 116.
 
 786 INDEX. 
 
 Staphylinidae, hornlike processes in male, 338. 
 
 Starfishes, parental feeling in, 120; bright colors of some, 295. 
 
 Stark, Dr., on the death-rate in towns and rural districts, 157; on 
 the influence of marriage on mortality, 158; on the higher mortality 
 of males in Scotland, 275. 
 
 Starling, American field, pugnacity of male, 417 ; red- winged, 
 selection of a mate by the female, 472. 
 
 Starlings, three, frequenting the same nest, 248, 464; new mates 
 found by, 464. 
 
 Statutes, Greek, Egyptian, Assyrian, etc., contrasted, 663. 
 
 Stature, dependence of, upon local influences, 34. 
 
 Staudinger, Dr., on breeding Lepidoptera, 284; his list of Lepidop- 
 tera, 284. 
 
 Staunton, Sir G., hatred of indecency a modern virtue, 135. 
 
 Stealing of bright objects by birds, 469. 
 
 Stebbing, T. R., on the nakedness of the human body, 685. 
 
 Stemmatopus, 603. 
 
 Stendhal, see Bombet. 
 
 Stendbothrus pratorum, stridulation, 324. 
 
 Stephen, Mr. L., on the difference in the minds of men and 
 animals, 88; on general concepts in animals, 100; distinction between 
 material and formal morality, 125. 
 
 Sterility, general, of sole daughters, 153; when crossed, a dis- 
 tinctive character of species, 189 ; under changed conditions 
 215, 217. 
 
 Sterna, seasonal change of plumage in, 561. 
 
 Stickle-back, polygamous, 249; male, courtship of the, 376; male, 
 brilliant coloring of, during the breeding-season, 386; nidification of 
 the, 391. 
 
 Sticks used as implements and weapons by monkeys, 91. 
 
 Sting in bees, 235. 
 
 Stokes, Capt., on the habits of the great bower-bird, 434. 
 
 Stoliczka, Dr., on colors in snakes, 399. 
 
 Stoliczka, on the pre-anal pores of lizards, 402. 
 
 Stonechat, young of the, 555. 
 
 Stone implements, difficulty of making, 55; as traces of extinct 
 tribes, 206. 
 
 Stones, used by monkeys for breaking hard fruits and as missiles, 
 56; piles of, 204. 
 
 Stork, black, sexual differences in the bronchi of the, 425; red 
 beak of the, 559. 
 
 Storks, 559, 562; sexual difference in the color of the eyes of, 483. 
 
 Strange, Mr. , on the satin bower-bird, 434. 
 
 Strepsiceros kudu, horns of, 583; markings of, 621. 
 
 Stretch, Mr., on the numerical proportions in the sexes of 
 chickens, 280. 
 
 Stridulation, by males of Theridion, 309; of Homiptera, 319; of 
 the Orthoptera and Homoptera discussed, 327; of beetles, 341. 
 
 Stripes, retained throughout groups of birds, 485; disappearance 
 of, in adult mammals, 624. 
 
 Strix flammea, 463. 
 
 Structure, existence of unserviceable modifications of, 68. 
 
 Struggle for existence, in man, 161, 166.
 
 INDEX. 787 
 
 Struthers, Dr., on the occurrence of the supra-condyloid foramen 
 in the hurnerus of man, 23. 
 
 Sturnella ludomciana, pugnacity of the male, 417. 
 
 Sturnus vulgans, 464. 
 
 Sub-species, 199. 
 
 Suffering, in strangers, indifference of savages to, 133. 
 
 Suicide, 155; formerly not regarded as a crime, 132; rarely prac- 
 ticed among the lowest savages, 133. 
 
 Suidae, stripes of young, 529. 
 
 Sulivan, Sir B. J., on speaking of parrots, 96; on two stallions 
 attacking a third, 571. 
 
 Sumatra, compression of the nose by the Malays of, 665. 
 
 Sumner, Archb., man alone capable of progressive improve- 
 ment, 89. 
 
 Sun-birds, nidification of, 517. 
 
 Superciliary ridge in man, 634, 636. 
 
 Supernumerary digits, more frequent in men than in women, 253; 
 inheritance of, 262; early development of, 268. 
 
 Superstitions, 164; prevalence of, 138. 
 
 Superstitious customs, 108. 
 
 Supra-condyloid foramen in the early progenitors of man, 182. 
 
 Suspicion, prevalence of, among animals, 78. 
 
 Swallow-tail butterfly, 354. 
 
 Swallows deserting their young, 122, 128. 
 
 Swan, black, wild, trachea of the, 424; white, young of, 550; red 
 beak of the, 559; black-necked, 562. 
 
 Swans, 559, 562; young, 548. 
 
 Swaysland, Mr., on the arrival of migratory birds, 240. 
 
 Swifts, migration of, 122. 
 
 Swinhoe, K., on the common rat in Formosa and China, 91; 
 behavior of lizards when caught, 403; on the sounds produced by 
 the male hoopoe, 427; on Dicrurus macrocercus and the spoonbill, 
 524; on the young of Ardeola, 534; on the habits of Turnix, 542; on 
 the habits of Rhynchcea bengalensis, 543; on Orioles breeding in 
 immature plumage, 552. 
 
 Sylvia atricapilla, young of, 554; sylma cinerea, aerial love-dance 
 of the male, 432. 
 
 Sympathy, 152; among animals, 115; its supposed basis, 120. 
 Sympathies, gradual widening of, 139. 
 Syngnathous fishes, abdominal pouch in male, 185. 
 
 heotides auritus, acuminated primaries of the male, 429; ear- 
 tufts of, 436. 
 
 Tabanidaj, habits of, 235. 
 
 Tadorna variegata, sexes and young of, 546; tadorna vulpan- 
 ser, 471. 
 
 Tahitians, 164; compression of the nose by the, 665. 
 
 Tail, rudimentary, occurrence of, in man, 25; convoluted body in 
 the extremity of the, 25; absence of, in man and the higher apes, 65; 
 variability of, in species of Macacus and in baboons, 65; presence of, 
 in the early progenitors of man, 182; length of, in pheasants, 507, 
 513, 514; difference of length of the, in the two sexes of birds, 513. 
 
 Tait, Lawson, on the effects of natural selection on civilized 
 nations, 151.
 
 786 INDEX. 
 
 Tanager, scarlet, variation in the male, 481. 
 
 Tanagra (estiva, age of mature plumage in, 551. 
 
 Tanagra rubra, 481 ; young of, 555. 
 
 Tanais, absence of mouth in the males of some species of, 235; rela 
 iions of the sexes in, 287; dimorphic males of a species of, 300. 
 
 Tankerville, Earl, on the battles of wild bulls, 571. 
 
 Tanysiptera, races of, determined from adult males, 533; tan&* 
 ttptera sylvia, long-tailed feathers of, 513. 
 
 Taphroderes distort us, enlarged left mandible of the male, 313. 
 
 Tapirs, longitudinal stripes of young, 529, 623. 
 
 Tarsi, dilatation of front, in male beetles, 312. 
 
 Tarsius, 178. 
 
 Tasmania, half-castes killed by the natives of, 194 
 
 Tasmanians, extinction of, 209. 
 
 Taste, in the Quadrumana, 618. 
 
 Tattooing, 203; universality of, 655. 
 
 Taylor, ., on Quiscalus major, 281. 
 
 Taylor, Rev. R., on tattooing in New Zealand, 657. 
 
 Tea, fondness of monkeys for, 7. 
 
 Teal, constancy of, 466. 
 
 Tear-sacs, of Ruminants, 604. 
 
 Teebay, Mr., on changes of plumage in spangled Hamburg 
 fowls, 259. 
 
 Teeth, rudimentary incisor, in Ruminants, 12; posterior molar in 
 man, 22; wisdom, 22; diversity of, 30; canine, in the early pro- 
 genitors of man, 182; canine, of male mammals, 572; in man, re- 
 duced by correlation, 641; staining of the, 655; front, knocked out 
 or filed by some savages, 656. 
 
 Tegetmeier, Mr., on the transmission of colors in pigeons by one 
 sex alone, 262; numerical proportion of male and female births in 
 dogs, 278; on the abundance of male pigeons, 280; on the wattles of 
 game-cocks, 458; on the courtship of fowls, 473; on the loves of 
 pigeons, 474; on dyed pigeons, 474; blue dragon pigeons, 508. 
 
 Tembeta, S., American ornament, 656. 
 
 Temper, in dogs and horses, inherited, 78. 
 
 Tench, proportion of the sexes in the, 282; brightness of male, 
 during breeding season, 386. 
 
 Tenebrionidae, stridulation of, 342. 
 
 Tennent, Sir J. E., on the tusks of the Ceylon elephant, 578, 587; 
 on the frequent absence of beard in the natives of Ceylon, 638; on 
 the Chinese opinion of the aspect of the Cingalese, 659. 
 
 Tennyson, A., on the control of thought, 139. 
 
 Tenthredinidae, proportions of the sexes in, 286; fighting habits of 
 male, 330; difference of the sexes in, 331. 
 
 Tephrod&rnis, young of, 533. 
 
 Terai, in India, 207. 
 
 Termites, habits of, 330. 
 
 Terns, white, 560; and black, 561; seasonal change of plumage 
 in, 560. 
 
 Terror, common action of, upon the lower animals and man, 77. 
 
 Testudo elegans, 398; tentudo nigra, 397. 
 
 Tetrao cupido, battles of, 417; sexual difference in the vocal 
 organs of, 422; ietrao phasianellus, dances of, 431; duration of
 
 INDEX. 789 
 
 Dances of, 460; tetrao scoticus, 518, 530, 537; tetrao tetrix, 518, 530, 
 537; pugnacity of the male, 412; tetrao umbellus, pairing of, 417; 
 battles of, 417; drumming of the male, 426; tetrao urogalloides, 
 dances of, 460; tetrao uroyallus, pugnacity of the male, 412; tetrao 
 urophasianus, inflation of the oesophagus in the male, 423. 
 
 Thamnobia, young of, 533. 
 
 Theda, sexual differences of coloring in species of, 351 ; thecla rubi, 
 protective coloring of, 353. 
 
 Thecophora fovea, 349. 
 
 Theognis, selection in mankind, 33. 
 
 TJiendion, stridulation of males of, 309; theridion lineatum, 308. 
 
 TJiomisus citreus, and T. floricolcns, difference of color in the sexes 
 of, 307. 
 
 Thompson, J. H., on the battles of sperm-whales, 571. 
 
 Thompson, W., on the coloring of the male char during the 
 breeding-season, 386; on the pugnacity of the males of GaUinula 
 chloropus, 409; on the finding of new mates by magpies, 462; on the 
 finding of new mates by Peregrine falcons, 463. 
 
 Thorax, processes of, in male beetles, 334. 
 
 Thorell, T. , on the proportion of the sexes in spiders, 287. 
 
 Thornback, difference in the teeth of the two sexes of the, 379. 
 
 Thoughts, control of, 139. 
 
 Thrush, pairing with a blackbird, 470; colors and nidification of 
 the, 518. 
 
 Thrushes, characters of young, 518, 529. 
 
 Thug, remorse of a, 133. 
 
 Thumb, absence of, in Ateles and Hyldbates, 57. 
 
 Thury, M. , on the numerical proportion of male and female births 
 among the Jews, 275. 
 
 ITiylacinus, possession of the marsupial sac by the male, 183. 
 
 Thysanura. 317. 
 
 Tibia, dilated, of the male Crabro cribrarius, 313; and femur, pro- 
 portions of, in the Aymara Indians, 39. 
 
 Tierra del Fuego, marriage-customs of, 683. 
 
 Tiger, colors and markings of the, 622. 
 
 Tigers, depopulation of districts by, in India, 52. 
 
 Tillus elongatus, difference of color in the sexes of, 333. 
 
 Timidity, variability of, in the same species, 78. 
 
 Tinea vulgaris, 282. 
 
 Tipula, pugnacity of male, 317. 
 
 Tits, sexual difference of color in, 521. 
 
 Toads, 395; male, treatment of ova by some, 185; male, ready to 
 breed before the female, 240. ft 
 
 Todas, infanticide and proportion of sexes, 288; practice polyandry, 
 677; choice of husbands among, 677. 
 
 Toe, great, condition of, in the human embryo, 12. 
 
 Tomicns mllosus, proportion of the sexes in, 286. 
 
 Tomtit, blue, sexual difference of color in the, 521. 
 
 Tonga Islands, beardlessness of the natives of, 639, 663. 
 
 Tooke, Home, on language, 97. 
 
 Tools, flint, 164; used by monkeys, 91; use of, 54. 
 
 Topn,ots in birds, 438. 
 
 Tortoise, voiqa of the male, 646,
 
 790 INDEX. 
 
 Tortures, submitted to by American savages, 134. 
 
 Totnnus, double moult in, 442. 
 
 Toucans, colors and oidification of tlie, 518; beaks and ceres erf 
 the, 560. 
 
 Towns, residence in, a cause of diminished stature, 35. 
 
 Toynbee, J. , on the external shell of the ear in man, 15. 
 
 Trachea, convoluted and imbedded in the sternum, in some birds, 
 425; structure of the, in Rhynchaa, 542. 
 
 Trades, affecting the form of the skull, 62. 
 
 Tragelaphus, sexual differences of color in, 611; tragelaphus 
 scriptus, dorsal crest of, 606; markings of, 621. 
 
 Tragopan, 249; swelling of the wattles of the male, during court- 
 ship, 434; display of plumage by the male, 451; marking of the 
 sexes of the, 487. 
 
 Tragops dispar, sexual difference in the color of, 399. 
 
 Training, effect of, on the mental difference between the sexes of 
 man, 645. 
 
 Transfer of male characters to female birds, 536. 
 
 Transmission, equal, of ornamental characters, to both sexes in 
 mammals, 618. 
 
 Traps, avoidance of, by animals, 90; use of, 54. 
 
 Treachery, to comrades, avoidance of, by savages, 126. 
 
 Tremex columbce, 331. 
 
 Tribes, extinct, 145; extinction of, 207. 
 
 Trichius, difference of color in the sexes of a species of, 833. 
 
 Trigla, 394. 
 
 Trigonocephalus, noise made by tail of, 401. 
 
 Trimen, R., on the proportion of the sexes in South African but- 
 terflies, 283; on the attraction of males by the female Lasiocampa 
 quercus, 284 ; on Pneumora, 326 ; on difference of color in the 
 sexes of beetles, 333; on moths brilliantly colored beneath, 357; on 
 mimicry in butterflies, 367, 368; on Gynanisa Isis, and on the ocel- 
 lated spots of Lepidoptera, 486; on Cytto Leda, 486. 
 
 Tringa, sexes and young of, 553; tringa cornuta, 444. 
 
 Triphcena, coloration of the species of, 355. 
 
 Tristram, H. B., on unhealthy districts in North Africa, 221; on the 
 habits of the chaffinch in Palestine, 281 ; on the birds of the Sahara, 
 519; on the animals inhabiting the Sahara, 557. 
 
 Triton cristatas, 394; triton palmipes, 394; triton punctatus, 394, 
 395. 
 
 Troglodyte skulls, greater than those of modern Frenchmen, 62. 
 
 Troglodytes vulgaris, 539. 
 
 Trogons, colors and nidification of the, 518. 
 
 Tropic-birds, white only when mature, 560. 
 
 Tropics, freshwater fishes of the, 389. 
 
 Trout, proportion of the sexes in, 281; male, pugnacity of 
 the, 377. 
 
 Trox sabulosus, stridulation of, 343. 
 
 Truth, not rare between members of the same tribe, 133; more 
 highly appreciated by certain tribes, 138. 
 
 Tullocli, Major, on the immunity of the negro from certain 
 fevers, 220. 
 
 Tumbler, almond 4 change of plumage in the, 269.
 
 INDEX. 791 
 
 Turdus meruln, 518; young of, 554; turdus migratorim, 529; 
 turdus musicus, 518; turdus polyglottus, young of, 554; turdus tor- 
 quatus, 518. 
 
 Turkey, wild, pugnacity of young male, 414; wild, notes of the, 
 425; swelling of the wattles of the male, 434; variety of, with a top- 
 knot, 488; recognition of a dog by a, 468; male, wild, acceptable to 
 domesticated females, 475 ; wild, first advances made by older 
 females, 477; wild, breast-tuft of bristles of the, 525. 
 
 Turkey-cock, scraping of the wings of, upon the ground, 426; 
 wild, display of plumage by, 447; fighting habits of, 458. 
 
 Turner, Prof. W., on muscular fasciculi in man referable to the 
 panniculus carnosus, 14; on the occurrence of the supra-condyloid 
 foramen in the human humerus, 24; on muscles attached to the 
 coccyx in man, 25; on the filum terminate in man, 25; on the varia- 
 bility of the muscles, 30; on abnormal conditions of the human 
 uterus, 43; on the development of the mammary glands, 184; on 
 male fishes hatching ova in their mouths, 185, 391 ; on the external 
 perpendicular fissure of the brain, 228; on the bridging convolutions 
 in the brain of a chimpanzee, 228. 
 
 Turnix, sexes of some species of, 542, 547. 
 
 Turtle-dove, cooing of the, 425. 
 
 Tuttle, H., on the number of species of man, 199. 
 
 Tylor, E. B., on emotional cries, gestures, etc., of man, 96; on the 
 origin of the belief in spiritual agencies, 106; remorse for violation 
 of tribal usage in marrying, 130; on the primitive barbarism of 
 civilized nations, 162; on the origin of counting, 162; inventions 
 of savages, 164 ; on resemblances, of the mental characters in 
 different races of man, 203. 
 
 Type of structure, prevalence of, 186. 
 
 TyphtiBUs, stridulating organs of, 341; stridulation of, 343. 
 
 Twins, tendency to produce, hereditary, 51. 
 
 Twite, proportion of the sexes in the, 281. 
 
 Ugliness, said to consist in an approach to the lower animals, 666. 
 
 Umbrella-bird, 423. 
 
 Umbrina, sounds produced by, 394. 
 
 United States, rate of increase in, 50; influence of natural selec- 
 tion on the progress of, 161 ; change undergone by Europeans in 
 the, 223. 
 
 Upupa epops, sounds produced by the male, 427. 
 
 Uraniidae, coloration of the, 356. 
 
 Uria troile, variety of (= U. lacrymans), 482. 
 
 Urodela, 394. 
 
 Urosticte Benjamim, sexual differences in, 502. 
 
 Use and disuse of parts, effects of, 36; influence of, on the racea 
 of man, 224. 
 
 Uterus, reversion in the, 43; more or less divided, in the human 
 subject, 43., 48; double, in the early progenitors of man, 183. 
 
 Vaccination, influence of, 151. 
 
 Vancouver Island, Mr. Sproat on the savages of, 208; natives of, 
 eradication of facial hair by the, 662. 
 
 Vanellus cnstatus, wing tubercles of the male, 414. 
 
 Vanessae, 350 ; resemblance of lower surface of, to bark of 
 trees, 3.53,
 
 792 INDEX. 
 
 Variability, causes of, 81 ; in man, analogous to that in the lower 
 animals, 33; of the races of man, 198 ; greater in men than in 
 women, 252; period of, relation of the, to sexual selection, 272; of 
 birds, 479; of secondary sexual characters in man, 638. 
 
 Variation, laws of, 83; correlated, 48; in man, 166; analogous, 173; 
 analogous, in plumage of birds, 438. 
 
 Variations, spontaneous, 49. 
 
 Varieties, absence of, between two species, evidence of their dis- 
 tinctness, 189. 
 
 Variety, an object in nature, 561. 
 
 Variola, communicable between man and the lower animals, 7. 
 
 Vaureal, human bones from, 24. 
 
 Veddahs, monogamous habits of, 675. 
 
 Veitch, Mr. , on the aversion of Japanese ladies to whiskers, 663- 
 
 Vengeance, instinct of, 127. 
 
 Venus Erycina, priestesses of, 670. 
 , Vermes, 299. 
 
 Vermiform appendage, 23. 
 
 Verreaux, M. , on the attraction of numerous males by the female 
 of an Australian Bombyx, 284. 
 
 Vertebrae, caudal, number of, in macaques and baboons, 65; of 
 monkeys, partly imbedded in the body, 66. 
 
 Vertebrata, 375; common origin of the, 180; most ancient progeni- 
 tors of, 183; origin of the voice in air breathing, 646. 
 
 Vesicula prostatica, the hoinologue of the uterus, 26, 183. 
 
 Vibrissae, represented by long hairs in the eyebrows, 20. 
 
 Vidua, 457, 526; mdua axUlans, 248. 
 
 Villerme, M., on the influence of plenty upon stature, 35. 
 
 Vinson, Aug., courtship of male spider, 308; on the male of 
 Epeira nigra, 309. 
 
 Viper, difference of the sexes in the, 398. 
 
 Virey, on the number of species of man, 199. 
 
 Virtues, originally social only, 132; gradual appreciation of, 148, 
 Viscera, variability of, in man, 30. 
 
 Vlacovich, Prof., on the ischio-pubic muscle, 46. 
 
 Vocal music of birds, 417; vocal organs of man, 98; of birds, 96, 
 612; of frogs, 397; of the Insessores, 421; difference of, in the sexes 
 of birds, 421; primarily used in relation to the propagation of the 
 species, 646. 
 
 Vogt, Karl, on the origin of species, 1; on the origin of man, 3; 
 on the semilunar fold in man, 19; on microcephalpus idiots, 40; on 
 the imitative faculties of microcephalous idiots, 98; on skulls from 
 Brazilian caves, 192, on the evolution of the races of man, 201; on 
 the formation of the skull in women, 635;. on the Ainos and negroes, 
 639; on the increased cranial difference of the sexes in man with 
 race development, 645; on the obliquity of the eye in the Chinese 
 and Japanese, 659. 
 
 Voice in mammals, 600; in monkeys and man, 636; in man, 645; 
 origin of, in air-breathing vertebrates, 646. 
 Von Baer, see Baer. 
 
 Vulpian, Prof., on the resemblance between the brains of man and 
 the higher apes, 6. 
 Vultures, selection of a, mate by ttie female, 473; colors of, 561.
 
 INDEX. 793 
 
 Waders, young of, 553. 
 
 Wagner, R., on the occurrence of the diastema in a Kaffir skull, 
 45; on the bronchi of the black stork, 425. 
 
 Wagtail, Ray's, arrival of the male before the female, 240. 
 
 Wagtails, Indian, young of, 534. 
 
 Waist, proportions of, in soldiers and sailors, 37. 
 
 Waitz, Prof., on the number of species of man, 199; on the liabil- 
 ity of negroes to tropical fevers after residence in a cold climate, 221; 
 on the color of Australian infants, 636; on the beardlessness of 
 negroes, 639; on the fondness of mankind for ornaments, 654; on 
 negro ideas of female beauty, 660; on Javan and Cochin Chineses 
 ideas of beauty, 661. 
 
 Waldeyer, M., on the hermaphroditism of the vertebrate em- 
 bryo, 183. 
 
 Wales, North, numerical proportions of male and female births 
 in, 274. 
 
 Walkenaer and Gervais, spider attracted by music, 309; on the 
 Myriapoda, 810. 
 
 Walker, Alex., on the large size of the hands of laborers' chil- 
 dren, 37. 
 
 Walker, F., on sexual differences in the diptera, 317. 
 
 Wallace, Dr. A,, on the prehensile use of the tarsi in male moths, 
 237; on the rearing of the Ailanihus silkmoth, 284; on breeding 
 Lepidoptera, 284; proportion of sexes of Bombyr cynthia, B. yama- 
 mai, and B. Pernyi reared by, 285; on the development of Bombyas 
 cynthia and B. yamamai, 315; on the pairing of Bonibyx cynthia, 360. 
 
 Wallace, A. R., on the origin of man, 3; on the power of imita- 
 tion in man, 77; on the use of missiles by the orang, 92; on the 
 vary appreciation of truth among different tribes, 138; on the limits 
 of natural selection in man, 144; on the occurrence of remorse among 
 savages, 149; on the effects of natural selection on civilized nations, 
 151 ; on the use of the convergence of the hair at the elbow in the 
 orang, 172; on the contrast in the characters of the Malays and 
 Papuans, 191; on the line of separation between the Papuans and 
 Malays, 192; on the birds of paradise, 248; on the sexes of Orni- 
 thoptera Crocus, 283; on protective resemblances, 295; on the rela- 
 tive sizes of the sexes of insects, 315; on Elaphomyia, 317; on the 
 pugnacity of the males of Leptorhynchus angustatus, 339; on sounds 
 produced by Euchirus longimanus, 344; on the colors of Diadema, 
 350; on Kallima, 353; on the protective coloring of moths, 355; on 
 bright coloration as protective in butterflies, 356; on variability in 
 the Papilionidae, 363; on male and female butterflies inhabiting dif- 
 ferent stations, 364; on the protective nature of the dull coloring of 
 female butterflies, 364, 365, 367; on mimicry in butterflies, 367; on 
 the bright colors of caterpillars, 369; on brightly colored fishes fre- 
 quenting reefs, 389; on the coral snakes, 400; on Paradisea apoda, 
 438; on the display of plumage by male birds of paradise, 449; on 
 assemblies of birds of paradise, 460; on the instability of the ocel- 
 lated spots in Hipparchia Janira, 486; on sexually limited inherit- 
 ance, 505; on the sexual coloration of birds, 514, 538, 539, 541. 546; 
 on the relation between the colors and nidification of birds, 515, 518; 
 on the coloration of the Cotingidae, 523; on the females of Paradise* 
 apoda and papvana, 535; on the incubation of the cassowary, 545;
 
 794 INDEX. 
 
 on protective coloration in birds, 556; on the Babirusa, 592; on the 
 markings of the tiger, 622; on the beards of the Papuans, 639; on 
 the hair of the Papuans, 656; on the distribution of hair on the 
 human body, 685. 
 
 Walrus, development of the nictitating membrane in the, 19; 
 tusks of the, 572, 578; use of the tusks by the, 585. 
 
 Walsh, B. D., on the proportion of the sexes in Papilio Turnus, 
 283; on the Cynipidae and Cecidomyidse, 286; on the jaws of Am- 
 mophila, 312; on Corydalis comutus, 312; on the prehensile organs 
 of male insects, 312; on the antennae of Penthe, 313; on the caudal 
 appendages of dragon flies, 313; on PlatypJiyllum concavum, 324; on 
 the sexes of the Ephemeridae, 328; on the difference of color in the 
 sexes of Spectrum femoratum, 328; on sexes of dragon flies, 328; on 
 the difference of the sexes in the Ichneumonidse, 331; on the sexes 
 of Orsodacna atra, 333; on the variation of the horns of the male 
 PMnceas carnifcx, 336; on the coloration of the species of Antho- 
 charis, 354. 
 
 Wapiti, battles of, 571; traces of horns in the female, 574; attack- 
 ing a man, 582; crest of the male, 606; sexual difference in the color 
 of the, 612. 
 
 Warbler, hedge, 539; young of the, 548. 
 
 Warblers, superb, nidification of, 517. 
 
 Wariness, acquired by animals, 91. 
 
 Warington, R., on the habits of the stickleback, 876, 891; on the 
 brilliant colors of the male stickleback during the breeding- 
 
 Wart-hog, tusks and pads of the, 593. 
 
 Watchmakers, short-sighted, 37. 
 
 Water-hen, 409. 
 
 Waterhouse, C. 0., on blind beetles, 333; on difference of color In 
 the sexes of beetles, 333. 
 
 Waterhouse, G. R., on the voice of Hyldbates agilis, 647. 
 
 Water-ouzel, 518; autumn song of the, 420. 
 
 Waterton, C., on the Bell-bird, 441; on the pairing of a Canada 
 goose with a Bernicle gander, 471; on hares fighting, 570. 
 
 Wattles, disadvantageous to male birds in fighting, 458. 
 
 Weale, J. Mansel, on a South African caterpillar, 369. 
 
 Wealth, influence of, 152. 
 
 Weapons, used by man, 54; employed by monkeys, 91; offensive, 
 of males, 238; of mammals, 571; et seq. 
 
 Weaver-bird, 420. 
 
 Weaver-birds, rattling of the wings of, 426; assemblies of, 460. 
 
 Webb, Dr., on the wisdom teeth, 22. 
 
 Wedderburn, Mr., assembly of black game, 462. 
 
 Wedgwood, Hensleigh, on the origin of language, 98. 
 
 Weevils, sexual difference in length of snout in some, 235. 
 
 Weir, Harrison, on the numerical proportion of the sexes In pigs 
 and rabbits, 279; on the sexes of young pigeons, 280; on the songs of 
 birds, 418; on pigeons, 467; on the dislike of blue pigeons to other 
 colored varieties, 474; on the desertion of their mates by female 
 pigeons, 475. 
 
 Weir, J. Jenner, on the nightingale and blackcap, 240; on the 
 relative sexual maturity of ma^e birds, 241; on female pigeons
 
 INDEX. 795 
 
 deserting a feeble mate, 242; on three starlings frequenting the aame 
 nest, 248; on the proportion of the sexes in Machetes pugnax and 
 other birds, 280; on the coloration of the TripluKna, 355; on the 
 rejection of certain catapillars by birds, 369; on sexual differences of 
 the beak in the goldfinch, 408; on a piping bullfinch, 418; on the object 
 of the nightingale's song, 418; on song-birds, 419; on the pugnacity 
 of male fine-pluinaged birds, 454; on the courtship of birds, 455; on 
 the finding of new mates by Peregrine-falcons and Kestrels, 463; on 
 the bullfinch and starling, 464; on the cause of birds remaining un- 
 paired, 465; on starling and parrots living in triplets, 466; on recog- 
 nition of color by birds, 468; on hybrid birds, 470; on the selection 
 of a greenfinch by a female canary, 472; on a case of rivalry of 
 female bullfinches, 477; on the maturity of the golden-pheasant, 551. 
 
 Weisbach, Dr. , measurement of men of different races, 191 ; on the 
 greater variability of men than of women, 252; on the relative pro- 
 portions of the body in the sexes of different races of man, 638. 
 
 Weismann, Prof., colors of Lyccence, 354. 
 
 Welcker, M. , on brachycephaly and dolichocephaly, 63; on sexual 
 differences in the skull in man, 635. 
 
 Wells, Dr., on the immunity of colored races from certain 
 poisons, 220. 
 
 Westring, on the stridulation of males of Theridion, 309; on the 
 stridulation of Reduvius personatus, 319; on the stridulation of bee- 
 tles, 343; on the stridulation of Omaloplia brunnea, 344; on the 
 stridulating organs of the Coleoptera, 345; on sounds produced by 
 Cychrus, 344. 
 
 Westropp, H. M., on reason in a bear, 86; on the prevalence of 
 certain forms of ornamentation, 203. 
 
 Westwood, J. O., on the classification of the Hymenoptera, 168; on 
 the Culicidae and Tabanidse, 235; on a Hymenopterous parasite with 
 a sedentary male, 251 ; on the proportions of the sexes in Lucanut 
 eermts and Siagonium, 286; on the absence of ocelli in female Mut- 
 illidsa, 311; on the jaws of Ammophila, 312; on the copulation of 
 insects of distinct species, 312; on the male of CraSbro cribrarius, 312; 
 on the pugnacity of male Tipulce. 317; on the stridulation of Pirate* 
 ttridulus, 319; on the Cicadse, 319; on the stridulating organs of the 
 cricket, 322; on Ephippiger mtium, 323; on Pneumora, 325; on the 
 pugnacity of the Mantides, 327; on Platyblemnm, 327; on difference 
 in the sexes of the Agrionidae, 328; on the pugnacity of the males of 
 a species of Tenthredinae, 330; on the pugnacity of the male stag- 
 beetle, 339; on Bledius taurus and Siagonium, 388; on lamellicom 
 beetles, 341; on the coloration of Lithosia, 356. 
 
 Whale, Sperm, battles of male, 570, 588. 
 
 Whales, nakedness of, 63. 
 
 Whateley, Arch., language not peculiar to man, 95; on the primi- 
 tive civilization of man, 162. 
 
 Whewell, Prof., on maternal affection, 78. 
 
 Whiskers, in monkeys, 171. 
 
 White, F. B., noise produced by Hylophila, 349. 
 
 White, Gilbert, on the proportion of the sexes in the partridge, 280; 
 on the: house-cricket, 821; on the object of the song of birds, 419; on 
 the finding of new mates by white owls, 466; on epring convey* of 
 male partridges, 466. 464.
 
 796 INDEX. 
 
 Whiteness, a sexual ornament in some birds, 563; of mammals in. 
 habiting snowy countries, 619. 
 
 White-throat, aerial love-dance of the male, 432. 
 
 Whitney, Prof., on the development of language, 97; language 
 not indispensable for thought, 100. 
 
 Widgeon, pairing with a pintail duck, 471. 
 
 Widow-bird, polygamous, 248; breeding plumage of the male, 445, 
 457; female, rejecting the unadorned male, 476. 
 
 Widows and widowers, mortality of, 158. 
 
 Wilckens, Dr., on the modification of domestic animals in mount- 
 ainous regions, 40; on a numerical relation between the hairs and 
 excretory pores in sheep, 225. 
 
 Wilder, Dr. Burt, on the greater frequency of supernumerary 
 digits in men than in women, 253. 
 
 Williams, on the marriage-customs of the Fijians, 684. 
 
 Wilson, Dr., on the conical heads of the natives of Northwestern 
 Africa, 665; on the Fijians, 665; on the persistence of the fashion of 
 compressing the skull, 666. 
 
 Wing-spurs, 413, 511. 
 
 Wings, differences of, in the two sexes of butterflies and Hymen, 
 optera, 314; play of, in the courtship of birds, 455. 
 
 Winter, change of color of mammals in, 619. 
 
 Witchcraft, 108. 
 
 Wives, traces of the forcible capture of, 163. 
 
 Wolf, winter change of the, 619. 
 
 Wolff, on the variability of the viscera in man, 30. 
 
 Wollaston, T. V., on Eurygnathm, 314; on musical Curculionidae, 
 341; on the stridulation of Acattes, 346. 
 
 Wolves learning to bark from dogs, 82; hunting in packs, 114; 
 black, 616. 
 
 Wombat, black varieties of the, 616. 
 
 Women distinguished from men by male monkeys, 9; preponder- 
 ance of, in numbers, 276; selection of, for beauty, 682; effects of 
 selection of, in accordance with different standards of beauty, 666; 
 practice of capturing 673, 676; early bethrothals and slavery of, 677; 
 freedom of selection by, in savage tribes, 683. 
 
 Wonder, manifestations of, by animals, 80. 
 
 Wonfor, Mr., on sexual peculiarities in the wings of butterflies, 314; 
 Wood, J., on muscular variations in man, 29, 46, 47; on the greater 
 variability of the muscles in men than in women, 253; Wood, T. W., 
 on the coloring of the orange-tip butterfly, 855; on the habits of th 
 Saturniidae, 358; quarrels of chamaelepns, 405 ; on the habits of 
 Menura Alberti, 421 ; on Tetrao cupido, 422 ; on the display of 
 plumage by male pheasants, 449, 451; on the ocellated spots of the 
 Argus pheasant, 501; on fighting of Menura superba, 461; on the 
 habits of the female cassowary, 545. 
 
 Woodcock, coloration of the, 559. 
 
 Woodpecker, selection of a mate by the female, 472. 
 
 Woodpeckers, 421 ; tapping of, 426; colors and nidification of the, 
 618, 521, 529; characters of young, 540, 548, 557. 
 
 Woolner, Mr., observations on the ear in man, 16. 
 
 Wormald, Mr., on the coloration of Hypopyra, 357. 
 
 Wounds, healing of, 8.
 
 INDEX. 797 
 
 Wren,539; young of the, 539, 548. 
 
 Wright, C. A., on the young of Oroeetes and Petrocinda, 554; 
 Wright, Chauncey, great brain-power requisite for language 54; on 
 correlative acquisition, 651 ; on the enlargement of the brain in 
 man, 697; Wright, Mr., on the Scotch deerhound, 689; on sexual 
 preference in dogs, 597; on the rejection of a horse by a mare, 598; 
 Wright, W., von, on the protective plumage of the Ptarmigan, 448. 
 
 Writing, 163. 
 
 Wyman, Prof., on the prolongation of the coccyx in the human 
 embryo, 10; on the condition of the great toe in the human 
 embryo, 12; on the occurrence of the supra-condyloid foramen in the 
 humerus of man, 24; on variation in the skulls of the natives of the 
 Sandwich Islands, 29; on the hatching of the eggs in the mouths 
 and branchial cavities of male fishes, 185, 391. 
 
 Xenarchus, on the Cicadae, 319. 
 
 Xenophon, selection in mankind advocated by, 82. 
 
 Xenorhynchus, sexual difference in the color of the eyes in, 483. 
 
 XipJiophorus HeUerii, peculiar analfin of the male, 382. 
 
 Xylocopa, difference of the sexes in, 381. 
 
 Yarrell, W., on the habits of the Cyprinidae, 282; on Raid clavata, 
 375; on the characters of the male salmon during the breeding- 
 season, 377, 386; on the characters of the rays, 380; on the gemmeous 
 dragonet, 381; on colors of the salmon, 386; on the spawning of the 
 salmon, 390; on the incubation of the Lophobranchii, 392; on rivalry 
 in song-birds, 419; on the trachea of the swan, 425; on the moulting 
 of the Anatidae, 446; on the young of the waders, 553. 
 
 Yellow fever, immunity of negroes and mulattoes from, 220. 
 
 Youatt, Mr., on the development of the horns in cattle, 266. 
 
 Yura-caras, their notions of beauty, 661. 
 
 Zebra, rejection of an ass by a female, 617; stripes of the, 823. 
 
 Zebus, humps of, 608. 
 
 Zigzags, prevalence of, as ornaments, 204. 
 
 Zincke, Mr., on European emigration to America, 161. 
 
 Zootoca vimpara, sexual difference in the color of, 405. 
 
 Zouteveen, Dr., polydactylism, 42; proportion of sexes at Cape of 
 Good Hope, 275; spiders attracted by music, 309; on sounds pro- 
 duced by fish, 394. 
 
 Zygaenidse, coloration of the, 356. 
 
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