BK>SCNCE6UBRARy /III LIMAIY CAUFOtNIA DESCRIPTIVE CATALOGUE OF THE TERATOLOGICAL SERIES THE MUSEUM OF THE ROYAL COLLEGE OF SURGEONS OF ENGLAND. BY B. THOMPSON LO_WNE, M.R.C.S., LECTURER ON PHYSIOLOGY AT THE MIDDLESEX HOSPITAL. LONDON: PRINTED FOR THE COLLEGE, AND SOLD BY R. HARDWICKE, 192 PICCADILLY. 1872. PRINTED BY TAYLOR AND FRANCIS, RE1> LION COURT, FLEET STREET. THE present Catalogue contains a description of the Spe- cimens in the Museum formerly described in the ' Cata- logue of the Contents of the Museum, Part V. compre- hending the Preparations of Monsters and Malformed Parts, 1831/ as well as of the Specimens of a similar nature which have been added to the Collection since the publication of that work. The whole have been rearranged and redescribed by Mr. Lowne 5 to whom this duty has been entrusted by the Council of the College. W. H. FLOWER, Conservator. October 1st, 1872. A 2 INTRODUCTION. " BY the classification of any series of objects, is meant the actual or ideal arrangement together of those which are like, and the separation of those which are unlike ; the pur- pose of this arrangement being to facilitate the operations of the mind in clearly conceiving and retaining in the me- mory the characters of the objects in question " *. In the animal and vegetable kingdoms there is a mar- vellous interconnexion of organisms, perhaps genetic in its origin, which enables us to classify them into groups based upon purely structural considerations. Such a classifica- tion has been well termed " morphological." Amongst malformations there is no such interconnexion. Parts of organisms which have no morphological relation with each other are affected by causes which are very dif- ferent in their nature and working. In such cases we must not seek for a morphological classification ; we have to deal with phenomena which may or may not be connected with or dependent on each other, and the only satisfactory method of arrangement must be physiological. The classification of malformations on these principles, to be entirely satisfactory, would require an intimate ac- quaintance with the laws of abnormal development, and the causes producing deviations from the normal standard. At * Huxley, ' Lectures on the Elements of Comparative Anatomy,' p. 1. VI INTRODUCTION. present we possess no such knowledge as this ; but what is known affords sufficient data for a physiological classifica- tion, which, if not entirely satisfactory, nevertheless ap- proximates sufficiently nearly to a satisfactory arrangement to fulfil the objects of classification to a very considerable extent. Although the causes producing malformations are themselves hidden in the deepest obscurity, their effects are sufficiently definite to admit of a very clear diagnosis and arrangement, whenever the first deviation of structure can be perceived and studied apart from the various modifi- cations which succeed and depend upon it. The primary deviation from the normal type may be looked upon as the immediate cause of the malformation. All the successive changes and aberrations which depend upon it bear a distinct morphological relation to each other and to the primary deviation. Hence when malformations belong to the same group (that is, when the primary de- viations are the same), they bear a distinct morphological relation to each other and admit of a morphological classi- fication. From these considerations it is evident that malforma- tions due to the same cause affecting morphologically similar parts may be arranged in groups, the members of which are morphologically related, although the groups themselves can only be arranged in classes by a knowledge of the physiological relation which they bear to each other. Such an arrangement is possible in many cases, because analogy leads to the belief that the causes determining the occur- rence of the malformations included in these groups are similar. In some the first deviations from the normal type are clearly of the same nature, or due to identical or nearly identical causes ; we are then able to class the re- sulting forms with certainty in one class ; but a number occur in which the primary deviation is too obscure to admit of this. Hence Bischoff argued that no satisfactory classi- fication could be drawn from any but purely anatomical grounds, and many authors have followed this principle PATHOLOGY AND TERATOLOGY. Vll strictly ; every day, however, the difficulties of a physio- logical classification will become less, and it may confi- dently be predicted that in a few years this subject will emerge from the darkness in which it has hitherto been involved. PATHOLOGY has for its domain the consideration of the abnormal conditions of nutrition which occur in living bodies. Every disease maybe looked upon as an abnormal condition of nutrition, using that term in its widest sense, whether the deviation be structural or apparently only functional. TERATOLOGY has for its domain the consideration of abnormal conditions of development. In so far as the function of development is separable from the functions of maintenance and repair, Teratology is separable from Pa- thology ; but there are a large number of intermediate conditions in which it is impossible to distinguish between aberrations of nutrition and of development. Again, there are *various abnormal conditions of growth which may be considered to belong to either class of phenomena. Hence, by common consent, all the diseases peculiar to intra-uterine life, together with certain abnormal congenital conditions of growth, producing dwarfs and giants, have been assigned to the Teratologist. As we know that all the functions and parts of the living body are prone to vary within certain limits, so we are justified in believing that the process of development is liable to a certain amount of variation. In some few cases it can be shown that slight variations may occur in differ- ent stages of the developmental process. Thus the occur- rence of transposition, or situs mutatus, of the non-symme- trical viscera is not very unfrequent ; and we owe to Von Baer the following interesting theoretical explanation of its occurrence : " The embryo of a bird during the first thirty-six hours lies with its abdominal surface downwards ; but in the course of the third day of incubation in the egg of the Vlll INTRODUCTION. common Fowl a change of position occurs, so that the left side of the embryo comes to be laid on the adjacent surface of the yelk. Von Baer had remarked, in very rare in- stances in the bird's egg, more frequently in the ovum of the Pig, the embryo lying with its right side towards the yelk ; and he has ingeniously supposed that the re- version of the viscera is connected with this malposition of the embryo"*. If such be the case, transposition of the viscera may be fairly regarded as a mere variation of the developmental process. Again, the aortic arches are liable to vary somewhat in the manner and period of their obliteration. It may be fairly assumed that variation is liable to occur in the developmental process at any stage, and disease is undoubtedly liable to do so. When either occurs in the later stages, there is usually no difficulty in tracing the re- sulting malformation to its proximal cause ; but when the first deviation arises from variation in the process of de- velopment or disease in the earlier stages of development, the resulting malformation is often exceedingly complex, so that it is only by a careful examination of a large series of allied malformations that we can obtain any clue to the nature of the original deviation. Whatever the causes of embryonic disease and variation may be, there can be no doubt that these conditions react upon each other. Variation is extremely liable to occur as an accompaniment to disease, probably because new conditions arise ; and, on the other hand, disease fre- quently results from variation. Again, disease passes by insensible degrees into variation, and hence no definite line can be drawn between malformations and varieties on the one hand and diseases on the other. Ordinary varieties, as well as the more marked degrees, of variation may be fairly looked upon as the result of variations in the develop- mental process ; they have therefore been grouped together * Allen Thomson, Lond. & Edinb. Med. Journ. 1844. CLASSIFICATION. IX into a single Class. Other deviations of form arise un- doubtedly from intra-uterine disease, and certain abnormal forms of nutrition give rise to dwarfs and giants ; these have been arranged in three Classes Diseases, Arrests, and Excesses of Growth. Two great Classes of malfor- mations remain Arrests of Development, which are con- nected with variations on the one hand and with diseases on the other ; and Double Conditions, either of the whole organism or of a limb or part, concerning the nature of which much difference of opinion exists. The- following six Classes have therefore been adopted in the arrangement of the Teratological Collection : Class I. Variation. II. Duplicity. III. Excess of Growth. IV. Arrest of Growth. V. Arrest of Development. VI. Disease. These great divisions, as has been already indicated, are by no means to be looked upon as certainly fixed; they are convenient groupings together of phenomena which are apparently related to each other. Analogy leads us to sus- pect that the causes in each Class are similar ; but further investigation may lead to a redistribution of some groups, and perhaps to some alterations in the number and nomen- clature of the classes themselves. Although the above-enumerated Classes are used as the basis of classification in this Catalogue, it has been found convenient to make them subservient to an artificial grouping of the preparations in the following order : Series I. Abnormal conditions in Plants. II. Abnormal conditions of the Axis in Animals. III. Abnormal conditions of the Limbs. IV. Abnormal conditions of the Skin and its Ap- pendages. INTRODUCTION. Series V. Abnormal conditions of the Osseous and Mus- cular Systems*. VI. Abnormal conditions of the Sensory Organs. VII. Abnormal conditions of the Heart and Vessels, VIII. Abnormal conditions of Blood-glands. IX. Abnormal conditions of the Digestive Organs. X. Abnormal conditions of the Urinary and Genera- tive Organs. XI. Abnormal conditions of the Oviduct and Ova of Birds f. There are many practical reasons why the malformations of each set of organs should be arranged in a separate Series ; it facilitates comparison and reference, and is in accordance with the general plan of arrangement of other parts of this Museum. The following considerations on the character and extent of each of the six Classes which have been adopted may be most conveniently discussed in the present portion of this work. Class I. VARIATION. Syn. Hemiteries, Geoff. The term variety is used by naturalists to designate the result of gradually accumulated individual differences, which are themselves slight variations. Some variations are, from their very nature, of a more marked character than ordinary * Abnormal conditions of the osseous and muscular systems are so intimately connected with each other that they have been arranged in a single Series. f This Series consists of preparations of eggs which are evidently the result of abnormal conditions or functional derangement of the oviduct, and which throw little* or no light upon the more remarkable deviations which occur in the other Series. It may be looked upon as supple- mental to Series X., and it has therefore been placed last in the col- lection. Specimens of abnormal condition of the oviduct have also been arranged in this series, although, in strict conformity with the general plan of the Catalogue, they should have been placed in Series X. : this has been done because they elucidate, in some instances, the condition of the eggs. VARIATION. XI individual differences ; such are variations in the number of organs : organs which are often repeated in an organism are extremely prone to vary in number, and such variations are clearly nearly allied to ordinary individual differences. The effect of altered conditions frequently produces varia- tion by a definite action, certain conditions always pro- ducing similar variation ; such variation is usually more considerable than ordinary individual differences. Varia- tions sometimes arise suddenly, it may be by reversion to an anterior type ; but in most cases it is either extremely difficult or impossible to distinguish between reversions and well-marked variations produced by other causes. Variations are frequently transmitted from generation to generation, and the abnormality sometimes increases, some- times diminishes in intensity in each succeeding generation. The more marked forms of variation are, however, rarer and less truly transmitted than those which exhibit less considerable deviation from the usual type. The following principal groups of malformations have been included under this Class : 1. Variations in the position of parts. Situs mutatus, or transposition of the viscera, a condition already ad- verted to. 2. Variations in the number of parts which are normally repeated several times, such as cases of an additional or deficient rib, or pair of ribs, or vertebra ; or, in plants, of additional or deficient carpels, stamens, &c. The various forms of polydactylism have also been in- cluded under this Class, although some are evidently very different to others in their nature. Any division founded on the few specimens which are available would, however, have been far too hazardous : it has therefore been thought best to place all the specimens in one group ; and as the greater part may probably be looked upon as variations, the whole have been included in this Class. It is a well-known law that multiple organs are more prone to vary in number than those which are not repeated. Xll INTRODUCTION. At an early stage of development the digits may fairly be looked upon as multiple organs, as they differ in no way from each other; it is not therefore surprising that the number should frequently vary. As development proceeds, however, and each digit becomes differentiated to its peculiar characters, there is apparently a stronger and stronger tendency for supernumerary digits to disappear. The disappearance of these abnormal digits takes place according to a well-defined law, which appertains not only in all such cases, but also occurs normally in the Mammalia, where the typical number of digits is less than five and rudiments of the absent digits remain. The metacarpal or metatarsal bone is the first to dis- appear, and the phalanges remain loosely attached to the skin and neighbouring bones by ligamentous tissue ; the basal and median phalanges are lost next in order, and the ungual phalanx in a rudimentary condition, or the ex- tremity of the digit or nail, only remains to mark the former existence of a digit. Sometimes, but very rarely, a normal functional digit disappears in the same manner (see No. 327). Many ruminants exhibit this condition in rudimentary outer and inner digits. Additional digits are occasionally developed, and usually exhibit the characters of the next normal digit more or less closely, oftener, however, resembling that of the opposite hand or foot than the corresponding digit of the same limb. It occasionally, but very rarely, happens that the number of digits in the opposite limb is deficient ; and this has given rise to the erroneous belief in compensation of growth, loi de balancement (Geoffrey), between the two extremities. It is by no means rare in such cases for an additional carpal bone to be intercalated between the normal bones ; it usually resembles the trapezoid bone in the hand and the second cuneiform bone in the foot. It is worthy of careful consideration that the addition of digits is far more frequent in hoofed than in unguiculate VARIATION. Xll animals, and is often so excessive in them that the whole manus or pes becomes doubled and usually exhibits the appearance of a right and left manus or pes united together. This condition is excessively rare in the Unguiculata ; one case only is recorded in man *. Another kind of polydactylism, confined to animals with less than five toes, arises from the redevelopment of some of the absent digits : No. 302 exhibits this condition in the Horsef. A similar condition perhaps occurs in the domestic Dog, where the inner toe of the pes is frequently developed : it appears, however, to be abnormal in having three phalanges instead of two ; at least if there are only two the metatarsal bone is removed from its normal and very constant position. In the St. Bernard Dog this inner toe is double, that is, six toes characterize the pes ; so that in this case the supernu- merary toes may probably be looked upon as entirely addi- tional, as they are in the Dorking Fowl, where such digits characterize the breed (see Nos. 294 and 295). Lastly, sometimes a digit or a whole limb exhibits unmistakable dichotomy : No. 307 presents this condition, and the Musee Dupuytren contains a similar human foot. It is not possible, however, to distinguish dichotomy of a digit in all cases from mere addition ; it is probable, however, that the conditions are really very distinct. The theory that such additional parts originate from the fusion of twin embryos may be looked upon as entirely superseded J. 3. Variations in the lobulation of the spleen. The num- ber of transitional states between an entire spleen and one much lobulated or divided render it probable that the most marked cases of lobulation and division of that organ are properly considered as mere varieties. 4. Variations in the form and arrangement of muscles ; reversions to anterior types in the muscular and osseous systems. * J. J. Murray, Med.-Chir. Trans, vol. xlvi. p. 29. t Wood-Mason, Proc. Asiat. Soc. Beng. 1871, p. 24. J Schultze, Virchow's Archiv, Bd. xvii. p. 484. INTRODUCTION. 5. Variations in the disposition of the blood-vessels, and especially of the large trunks given off from the aorta. Class II. DUPLICITY. This Class contains a vast number of very remarkable conditions, at first sight extremely dissimilar, but clearly, on closer study, intimately related in their mode of origin. The forms included in this Class have been divided into three Subclasses : Subclass I. Dichotomy. II. Homologous union. III. Heterologous union. I. Dichotomy, or fission as it is frequently called, con- sists in the formation of two growing points in the place of one, in such a manner as to produce a dichotomously divided embryo or part, each half of the doubled portion being complete in itself. This process occurs normally in the production of a branching axis in plants, and is not un- frequent in the multiplication of Ccelenterates, in the division of Coral-polypes and certain branched Hydrozoa. The use of the term fission to designate this condition is unfortunate, as it implies the division of an already formed part ; whilst Dichotomy in both animals and plants, either normal or abnormal, as has been carefully pointed out by Dr. Maxwell T. Masters in his 'Vegetable Teratology/ consists in the simultaneous production of two points of growth. Fission amongst coral-polypes is of this kind, a fact strongly insisted on by Milne-Edwards. The term has, indeed, been used to designate a totally distinct phenomenon in the Infusoria, where an already formed organism undergoes division. Dichotomy may probably arise from a cleavage of the original cells, out of which a part is developed ; but we know nothing certainly on this point. DUPLICITY. XV Amongst the Vertebrata dichotomy of the axis is by no means unknown ; it may occur at either extremity, but the posterior extremity is most frequently affected. This con- dition originates in dichotomy of the primitive groove and notochord. Many discussions have been held -and much difference of opinion exists as to its origin. That there is but a single germinal area is undoubted* ; but the question at issue is whether there were originally two grooves and two notochords arising from independent sources (i. e. possibly from two vesicles of Purkinje being present in a single ovumf or from the original fusion of two yelks) or from an originally simple ovum. The former hypothesis is unsubstantiated, since the occasional presence of two vesicles of Purkinje, or the fusion of two yelks in an ovum, which we do not know will produce a double embryo, cannot be regarded in the light of evidence ; and the hypothesis entirely fails to account for the presence of a single blastoderm, a single germinal area, or a dichotomous embryo : on the other hand, the view that excess of formative power or nutriment pro- duces a tendency to the complete or partial doubling of the embryo upon a single blastoderm, by the formation of two points of growth in the place of one, is borne out by numerous facts. The doubling of a single limb, although excessively rare, occurs at times (see No. 307), bearing out the view that a double axis is the result of dichotomy. The observations of Lereboullet on the ova of fishes points to the same conclusion. He says : " Le bourrelet en effet constitue le veritable germe em- bryonnaire, germe toujours simple, unique comme le vitellus que le blast oder me recouvre, mais susceptible quand le developpement se derange, de vegeter comme la substance dont se compose le corps des polypes, et de produire des formes variees qui montrent toujours une tendance manifeste * Vrolik, Allen Thomson, and others have placed this matter beyond doubt. f M. Coste, Coinptes Rendus, 1855, p. 931. XVI INTRODUCTION. a revenir au type primitif de 1'espece" *. Lereboullet states that this condition of the germinal disk gives rise to the formation of a more or less completely double primitive groove and notochord, although the tendency to revert to the primitive type often causes the two grooves to coalesce at one or both extremities, or throughout their entire length. II. The second Subclass, Homologous union, consists of monsters formed by the union of two distinct embryos adherent by the fusion of homologous parts ; each rib of the one, for instance, becomes fused with the corresponding rib of the other, and the other organs are all similarly united. The fact that such embryos originate in all cases upon a single yelk has been strongly insisted upon by most teratologists since the time of Vrolik, and double embryos on one yelk have been observed in numerous instances. Whenever the structures formed from the inner layer of the blastoderm, the intestinal canal and liver, are continuous, as they are in every case in the collection as well as in nearly if not in all the cases on record, it is impossible to conceive that the embryos could have originated in any other manner, since the adhesion of the parietes of the embryos by their external surfaces could not account for the continuity of the alimentary canal. M. Canaille Dareste believes, however, that cases of homologous union occur between embryos formed on separate yelks, oc- casionally at least. In homologous union the dorsal groove, instead of being only partially double, as in dichotomy, is completely double, and the two embryos are formed so close to each other that the visceral laminae become united. As union takes place before the differentiation of distinct organs oc- curs, these are formed in continuity with each other. The differentiation is probably gradual ; the ribs, for instance, instead of growing forwards from the spine and meeting in the mesial line, are probably gradually evolved from the cells of the visceral laminae. This evolution is continuous * Comptes Rendus, 1855, pp. 885 and 1029. DUPLICITY. XV11 throughout their entire length, but proceeds most rapidly in the dorsal region, so that they appear to grow forwards. The so-called affinity of " soi pour soi " of Geoffroy is probably quite imaginary ; for organs, when differentiated before union, probably in no case become united to homo- logous parts. This is well seen in preparations Nos. 120 and 123 to 130, 138, &c. It may be said to be a well-defined law that structures which are united before differentiation become double by the development of homologous structures in continuity with each other, a symmetrical double organ being formed ; whilst structures which are first developed and then united become fused irregularly with each other, giving rise to deformed and unsymmetrical structures. In such cases bone usually unites with bone, from the absorption of all intermediate tissues being effected by the pressure to which they are subjected between the two growing bones. Large portions of structures so united are com- monly deficient from absorption or atrophy. III. Cases of Heterologous union form the third sub- class. In these the parts of the two embryos are irregu- larly united, the adhesion resulting from the union of un- like structures. In most cases, at least, these malforma- tions result, like those in the two previous subclasses, from the formation of a double embryo on a single yelk. Several extremely complicated results occur from heterologous union; but they are best studied in individual cases. In some few instances of heterologous union it is possible that the second embryo may result from a second ovum, impregnated at a later date, finding its way into the cavity of the mem- branes of an earlier impregnation. No evidence can, however, be adduced in support of this view. Twins united in a common choronic or amniotic cavity are probably the normal result of the formation of a double embryo upon one yelk. There is a continuous and unbroken series of forms commencing with dichotomous and double monsters, passing through twins with a common cord and b XV111 INTRODUCTION. placenta, or a common amnion and distinct cords, to those which have separate ammo tic sacs but a common chorion. It is almost as difficult to conceive that two amniotic sacs from distinct yelks should unite by their edges as it is that two embryos should unite by their visceral laminae when enclosed in distinct amnia. Moreover, the yelk-cap- sule is probably persistent, and a seam at least would be apparent if the amnia were fused at a later period of deve- lopment by the absorption of those portions by which they are in contact. M. Dareste believes that the amniotic sacs produced from distinct yelks become fused together occa- sionally by their edges, and M. Broca has recorded several cases in which two amnia formed from distinct yelks com- municate or form a single amnion *. It would be of extreme importance to discover whether, in such cases, some traces at least of the primitive septum do not remain. The formation of double monsters may probably be looked upon, therefore, as an arrested attempt at something very like zooid reproduction, perhaps due to the germinal disk in its earliest state undergoing division, analogous to that which occurs as a normal mode of reproduction amongst the lower forms of life by a kind of reversion to a primitive type. This view will doubtless commend itself to some minds on mature consideration, although it may perhaps appear improbable to others. If two complete primitive grooves occur, any arrest in the growth of the blastoderm between them, or their too close approximation at their first formation, would obviously give rise to the subsequent union of the resulting embryos. These views are ably expounded by Dr. B. Schultze, in his essay 'Ueber anomale Duplicitat der Axenorgane'f, where he proposes a subdivision of double malformations on theoretical grounds, which is essentially the same as that adopted in the following pages. * C. Dareste, " Sur les ceufs a double germe," Ann. Sc. Nat. 1862, t. xvii. pp. 48 & 49. f Virchow's Archiv, Bd. xvii. p. 479. ARREST AND EXCESS OF GROWTH. XIX The fusion of distinct buds in plants, as in syncarpy (Prep. Nos. 6 to 14), is clearly a condition analogous to the union of embryos originating on a single yelk : in both cases the united growths probably originate by a similar process, the formation of two centres of growth in the place of one. A similar mode of union occurs normally between contiguous zooids in the Gorgonidse, or fan corals. In the eggs of birds three distinct conditions occur : First, there may be two yelks enclosed in a single shell ; this condition may give rise to two young, and if they become united they only adhere by heterologous parts, or possibly by the integument of the umbilicus *. Se- condly, there may be two cicatrices on one yelk : in this case the yelk is virtually equivalent to two mammalian yelks, as the cicatrix is the homologue of the mammalian yelk, the great food-yelk being absent in this Class f. Or, thirdly, two embryos may be formed on the same cicatrix : this condition is the most frequent, and gives rise either to twin chicks (?) or to double monsters. Dichotomy, as already stated, very rarely affects a limb or digit ; it is liable to occur in the kidneys. Doubling of the cavities of the heart, bladder, and uterus are malformations totally unlike those arising from dicho- tomy. The latter organ is certainly doubled by arrest of development. " Classes III. & IV. ARREST AND EXCESS OF GROWTH Include, first, dwarfs and giants, which are either the effect of variation of nutrition or development ; and, secondly, cases of partial excess or arrest, which are more nearly allied to ordinary disease : these may be considered as cases of nitra-uterine hypertrophy or atrophy. * There is no improbability in such union, and it appears to have been observed. M. Camille Dareste thinks this adhesion occurs. t E. van Beneden, ' Rccherches sur la composition et la significa- tion de 1'ceuf.' Bruxelles, 1870. XX INTRODUCTION. Class V. ARREST OF DEVELOPMENT. The most numerous and complicated groups of abnormal conditions are included in this Class ; but as it is extremely comprehensive and well defined, and as two or more forms of arrest are sometimes united in a single malformation, it is extremely doubtful whether any good would arise in the substitution of several Classes in its place, at least with our present knowledge of the subject. The various forms of arrest may be epitomized in the following manner : I. The normal evolution of an embryonic structure may fail, although its growth continues, so that an enlarge- ment of the embryonic condition results. It occurs in the external generative organs of the female, giving rise to a similarity to the male. The condition has the appearance of excessive development, but it is clearly due to the absence of the usual developmental change. Doubling of the female uterus by a septum, and the growth of the Miillerian duct and genital cord into an enormous organ in the male, are examples of this phenomenon. Some of the various kinds of atresia may probably be of a similar character. II. The second form of arrest of development is apparently due to an early arrest of growth in the lateral halves of such organs as are formed by the union of two symmetrical halves ; in extreme cases there is usually great accompany- ing defect of development in the lateral parts. Persist- ence of a cleft only, inasmuch as it is the persistence of an earlier condition, is an arrest of development. Fissure of the sternum, abdominal wall, palate, iris, &c. are of this kind, as are also the states known as ectopia vesicae, epi- spadias, and hypospadias. III. The third form also arises from, or is at least accom- panied by, arrest of growth and atrophy, so that an organ or part may be rudimentary, minute, or entirely absent. When median structures fail in this way in the axis of the body, the lateral parts coalesce at too early a period and ARREST OF DEVELOPMENT. XXI fusion results, with the absence of the parts which nor- mally intervene. The axis of the skull may fail to a greater or less extent, a condition accompanied by fusion of the eyes (cyclopia) and absence of the median structures of the nose, and usually accompanied by an arrested condition of the brain, in which, although growth has continued, evolu- tion has not; it probably arises from defective nutrition or atrophy of the axis of the skull, and may be considered as the result of very early embryonic disease. The various forms of facial fusion (Cyclopia, Ethmocepha- lus, &c.), certain defective conditions of the limbs (Perome- lid), fusion of the limbs (Sympodid], and deficiencies of other parts are also probably of this kind. IV. In the fourth form of arrest, differentiation fails at an early period ; this is seen most frequently in the intercostal spaces, a complete layer of bone being formed in the place of intercostal muscles between an adjacent pair of ribs. It usually accompanies severe forms of arrest in other parts. Sometimes no muscles exist, the whole body being formed of dense connective tissue, containing bones and cartilages. Other examples of this kind of arrest, which might fairly be called histological, occur. V. Lastly, the heart may undergo an arrest of develop- ment and atrophy at a very early period, so that ,an acardiac foetus results. Such malformations always exhibit great histological arrest ; many of the organs remain in an em- bryonic condition, although they may increase in size. Some parts become so altered that they can scarcely be recognized. The head is usually completely absent, or it consists of a mere bony cyst. Functionally active organs always undergo considerable after modification whenever their development has been arrested : this is especially seen in the heart. Other parts exhibit the conditions in a less degree. The pelvis No. 424 is a good example of this phenomenon : the pubic bones have been arrested in their growth in consequence of their taking no part in the support of the body, and they have XX11 INTEODUCTION. become widely separated by the manner in which the ilia and sacrum supported the weight of the trunk. With regard to the nature of the origin of arrest nothing is known positively. Like all malformations, some forms appear closely allied to variations, some to diseases. In arrest, however, the variations, if they be such, take the form of reversions. This may be more apparent than real ; but in some Ceases, where growth continues and evolution does not, it appears as if the parts are actually developed in conformity with an anterior type rather than simply arrested in their formation. Bilocularity of the human uterus, the formation of uterine cornua, enlargement of the clitoris, development of the uterus masculinus, hypospadias, the formation of a cloaca, webbing of the fingers, arrest of the ventricular septum of the heart, and the persistence of a spiracle uniting the pharynx and auditory meatus are ex- amples of this kind. Class VI. DISEASE. The last class of malformations consists of intra-uterine diseases and their results. The most marked forms are those of spinal and appendicular deformity, and dropsy of the central canal of the nervous system, giving rise to hydrocephalus, epicephalocele, spina bifida, &c. It will be observed that no class has been formed for malformations from excess of development ; for it may well be doubted if any such exist, unless under the forms of variation or duplicity. There are, however, some cases which might possibly be considered as the result of excess in the developmental process ; although, without more evidence, it appears inju- dicious to erect a class which all observations tend to render more and more hypothetical in its nature. Certain fishes, for instance, occasionally exhibit a very remarkable form of hermaphrodism in which a portion of an ovary is developed as a testis, whilst the remainder becomes a perfect ovary. DISEASE. XX111 It is by no means certain, however, that the testis should be looked upon as an excessive development ; it is equally possible that the ovary is formed by an arrest of a genera- tive gland which would otherwise have been a testicle. Sometimes an additional septum is formed in the heart ; but this may arise from mere hypertrophy of the musculi papil lares. In conclusion, attention is drawn to the desiderata in this collection ; for although it is a very splendid one, containing many almost unique preparations, it has deficiencies which could easily be supplied. Many forms of the lesser degrees of malformation which possess great practical interest, as hare-lip, hypospadias, &c., are nearly unrepresented ; whilst no collection has hitherto been made of variations in the conformation of muscles, bones, and vessels, which could not fail to possess great value, and to afford material aid in the study of Teratology. CONTENTS, SERIES I. ABNORMAL CONDITIONS IN PLANTS. No. of Preparations. CLASS I. VARIATION. 12 CLASS II. DUPLICITY. ^ * Subclass I. Dichotomy 3 4 Subclass II. Homologous union. a. Union of stems 5 oa b. Union of fruit 6 14 c. Union of seeds 15 d. Union of embryos 16 17 SERIES II. ABNORMAL CONDITIONS AFFECTING THE AXIS IN ANIMALS. CLASS I. VARIATION. a. Situs mutatus 18 19 CLASS II. DUPLICITY. Subseries I. IN INVERTEBRATES. Subclass I. Dichotomy 20 Subseries II. IN FISHES. Subclass II. Homologous union 21 22 Subseries III. IN AMPHIBIA. Subclass IY. Heterologous union 23 Subseries IV. IN REPTILES. Subclass I. Dichotomy. A. Anterior Dichotomy 24 27 B. Posterior Dichotomy ' . . . 28 Subseries V. IN BIRDS. Subclass I. Dichotomy. A. Anterior Dichotomy 2932 B. Posterior Dichotomy 3341 Subclass II. Homologous union. a. Pleuropagus 42 44 b. Hypogastrodidymus 45 46 XXVI CONTENTS. No. of Preparations. Subclass IV. Heterologous union 47 48 Subseries VI. IN MAMMALS. Subclass I. Dichotomy. A. Anterior Dichotomy. * In Animals. a. Diprosopus 49 61 b. Dicephalus 62 64 B. Posterior Dichotomy. * In Animals. a. Dipygus 6567 b. Schizorhachis 68 80 c. Schizocotis 81 84 d. Schizocephalus 85 86 ** In the Human foetus. a. Schizorhachis 87 b. Schizocotis 88 89 C. Antero-posterior Dichotomy 90 94 Subclass II. Homologous union. A. Prozygosis 9598 B. Opisthozygosis 99 104 C. Parazygosis. a. Xiphopagus 105 b. Thoracopagus 106 117 c. Pleuropagus 118 121 d. Pygopagus 122 Subclass III. Homologous union with dichotomy. Subclass IV. Heterologous union. A. By Impaction. a. Between the halves of the sternum . . 123 130 b. Between the facial arches 131 133 B. By Inclusion 134 137 C. By Adhesion. a. Craniopagus 138 b. Ischiopagus 139 CLASS III. EXCESS OP GROWTH. [Arranged in the Osteological Series. ,] CLASS IV. ARREST OP GROWTH. [Arranged in the Osteological Series.] CLASS V. ARREST OP DEVELOPMENT. Subclass I. Cranial arrest. IN PISHES 140 142 IN BIRDS 143144 IN MAMMALS. A. Facial arrest . , 145159 CONTENTS. XXVI No. of Preparations. B. Prosencephalic arrest. a. Khinocephalus 160178 b. Arhynchus 179186 c. Anopia 187189 C. Mesencephalic arrest 190 19 1 D. Epencephalic arrest. a. Agnathia 192 193 b. Synotia 194 199 E. Prostho-epencephalic arrest. a. Cyclocephalus 200209 b. Nanocephalus 210222 c. Acephalus 223 227 Subclass IT. Posterior axial arrest. a. Sympodia 228233 b. Monopodia 234237 Subclass III. Arrest of the tvhole axis 238 246 Subclass IV. Defective closure of the thoracic and abdominal cavities. a. Fissure of the sternum 247 248 b. Ectopia of the abdominal viscera .... 249 251 c. Deficiency of the diaphragm 252 255 CLASS VI. MALFORMATIONS OF THE AXIS FROM DISEASE. Subclass I. Curvature of the axis. a. Simple curvature , . . . 256 261 b. With ectopia of the viscera 262 264 Subclass II. Dropsy of the axial canal of the cere- bro -spinal system. a. Spina bifida 265277 b. Occipital deficiency 278 279 c. Epicephalocele 280281 Subclass III. Anencephalus 282292 SERIES III. ABNORMAL CONDITIONS OF THE LIMBS. I. IN INVERTEBRATES 293 II. IN VERTEBRATES. CLASS I. VARIATION. A. In the number of digits. a. Polydactylus 294313 CLASS II. DUPLICITY. (See Polydactylus.) XXV111 CONTENTS. No. of Preparations. CLASS III. EXCESS OF GROWTH 314 CLASS TV. ARREST OF GROWTH. A. In the Digits . 315317 B. In the Limbs 318322 CLASS V. ARREST OF DEVELOPMENT. A. Of the Digits. a. Aschistodactylus 323 326 b. Perodactylus 327 B. Of the Limbs. a. Ischnomelia 328332 b. Peromelia 333338 c. Micromelia 339 d. Amelia 340342 CLASS VI. MALFORMATIONS FROM DISEASE. A. Distortion. a. Talipes 343349 b. Congenital curvature 350 351 c. Congenital dislocation 352 353 SERIES IV. ABNORMAL CONDITIONS OF THE SKIN AND ITS APPENDAGES . 354363 SERIES V. ABNORMAL CONDITIONS OF THE OSSEOUS AND MUSCULAR SYSTEMS. A. Of the Sternum and Ribs , . 364369 SERIES VI. ABNORMAL CONDITIONS OF THE SENSORY ORGANS. A. Of the Eye 370373 SERIES VII. ABNORMAL CONDITIONS OF THE HEART AND VESSELS. CLASS I. VARIATION. a. Abnormal arrangement of the vessels . 374 375 b. Situs mutatus 376 c. In the number of arterial valves. d. Division of a ventricle 377 CLASSES II., III., & IV. have not occurred in this Series. CONTENTS. XXIX No. of Preparations. CLASS Y. AEBEST OF DEVELOPMENT. a. Arrested closure of the ductus arteriosus 378 b. Of the foramen ovale 379383 c. Of the ventricular septum 384 387 d. Of an artery. e. Premature closure of ductus arteriosus or foramen ovale. f. Of a valve 388 g. Deficiency of the pericardium. SERIES VIII. ABNORMAL CONDITIONS OF BLOOD-GLANDS. A. Of the Spleen 389390 SERIES IX. ABNORMAL CONDITIONS OF THE DIGESTIVE ORGANS. A. Of the Teeth 391393 B. Of the Alimentary Canal. CLASS Y. AEREST OF DEVELOPMENT. (The other Classes have not occurred in this Series.) a. Of the pharynx and oesophagus .... 394 396 b. Atresia of the rectum 397 407 SERIES X. ABNORMAL CONDITIONS OF THE URINARY AND GENERATIVE ORGANS. CLASS II. DUPLICITY. (Classes I., III., & IV. have not occurred in this Series.) Subclass I. Dichotomy. a. Of the Tcidney and ureter 408418 CLASS V. AREEST OF DEVELOPMENT. A. Of the Kidney 419 B. Of the anterior Abdominal wall and Bladder. a. Epispadias 420 b. Ectopia vesicce 421 425 XXX CONTENTS. No. of Preparations. C. Of the Urino -generative Tract. * In the Human subject. a. Hypospadias 426 b. Androgyny 427 c. Gynandry 428 430 ** In Animals. a. Hypospadias 431 434 b. Androgyny 435 444 c. Gynandry 445 d. HermapJirodism 446 449 B. Of the Uterus. a. Double uterus 450 453 b. Atresia of the os . 454 SERIES XI. ABNORMAL CONDITIONS OF THE OVIDUCT AND OVA OF BIRDS. A. Of the Oviduct. . . . 455456 B. Of the Ova. a. Twin Eggs 457 460 b. Of the coverings of the yelk 461466 c. Pseudo-Eggs 467 472 d. Included Eggs or Pseudo-Eggs 473 477 e. Fibrinous masses from the Oviduct . . 478 479 CATALOGUE. SERIES I. ABNORMAL CONDITIONS IN PLANTS. J-HIS small series illustrates very clearly the difference be- tween Variation, Dichotomy, and Homologous union, and throws much light on the nature of similar malformations in the animal kingdom. Class I. VARIATION. 1. A Walnut with three carpels instead of two, the normal number. This is a true case of variation. The additional carpel has pre- cisely similar relations to each of the normal carpels, and bears no evidence of having arisen from the fission of either of these. In many cases an additional part arises in plants from the develop- ment of one which exists at an early stage, but which usually fails by abortion. No third carpel, however, exists normally at any period of development in the fruit of the Walnut. Presented by J. Quekett, Esq., 1859. 2. The fruit of a Pea with three carpels instead of one. The third carpel is very small. There is but a single seed, and this is borne by the largest carpel. This case differs from the former in several particulars. The two additional carpels are by no means equally developed with the normal one ; many of the allies of the Pea (Leguminosce) normally possess three carpels, whilst the Walnut- tribe (Juglandece) either have two or four. The first case is probably one of simple varia- tion ; this is possibly one of reversion. B 2 ABNORMAL CONDITIONS IN PLANTS. Class II. DUPLICITY. Subclass I. Dichotomy. 3. A frond of the common Hart V tongue Fern, dichotomous in its upper part from fission. Presented by Mr. Clift, 1808. 4. A dichotomous ear of Wheat^ in which the culm is single. Presented by Mr. Sear son, 1871. Subclass II. Homologous union. a. Union of stems (Fasciatiori). 5. A double head of Cowslip-flowers with the flower-stalks slightly adherent through their entire length. Presented by Mrs. Scott, 1872. 50. A triple head of Teasel, probably produced by the cohesion of three axes. b. Union of fruit (Syncarpy). 6. Two Quinces on a single peduncle united by fusion of their sarcocarps. Presented by W. J. B. Smith, Esq., 1858. 7. Two Cherries united in the same manner. Presented by T. H. Stewart, Esq. 8. A similar specimen. Presented by Prescott G. Hewett, Esq., 1871. 9. Two Apples united in the same manner. Hunterian. 10. Two Apples similarly united, divided vertically to show the divergence of the axes of the two fruits. The tree from which this fruit was obtained produced a crop of similar fruit every year. Presented by Sir A. Carlisle, 1829. 1 1 . Two small Cucumbers on a single peduncle, adherent through their entire length, cut through transversely to show the manner in which they are united. Presented by W. J. B. Smith, Esq. 12. Two Cucumbers similarly united throughout two thirds of their length. Presented by W. Clift, Esq., 1829. 1.3. Two Cucumbers similarly united; the growth of one has been arrested, however, at a very early stage. Hunterian. ABNORMAL CONDITIONS IN ANIMALS. 3 14. Three Spanish Nuts united by their pericarps : union seems to have taken place during the later stages of develop- ment, as it is not complete, and the adjacent portions of the pericarps are flattened. A section has been made through the nuts. Presented by Prof. Flower, 1871. c. Union of seeds (Synspermy). 15. Two Bean-seeds united by their cotyledons near their hila, which are distinct. The testa is continuous over the two seeds. Hunterian. d. Union of embryos (Synophy). 16. Two seedling Orange-plants attached by their cotyledons; they were produced from a single seed. There are four cotyledons, but the two between the embryos are smaller and are closely adherent to one another. Presented by B. T. Lowne, Esq., 1871. 17. Three seedling Orange-plants growing from a single seed. The cotyledons are united between the embryos. The third embryo is very much smaller than the other two. " It occurs, not unfrequently, in the Orange and Hazel that more than one embryo is developed in a single testa ; and this condition is very common in the Coniferse, Cycas, the Onion, and the Mis seltoe. Now and then a union of these embryos takes place." (Lindley's ' Introduction to Botany.') Presented by B. T. Lowne, Esq., 1871. SERIES II. ABNORMAL CONDITIONS AFFECTING THE AXIS IN ANIMALS. Class I. VARIATION*. a. Situs mutatus (transposition of the viscera). This is the only class of phenomena affecting the whole axis which can be regarded as a variation. In the earliest stages * For remarks on the nature of Classes and Subclasses see the In- troduction. B2 4 ABNORMAL CONDITIONS OF THE AXIS. of the embryo the yelk is on its ventral surface, but soon the left side turns towards the yelk. Transposition of the viscera, as was long ago pointed out by Von Baer, probably arises from this turn taking place in the opposite direction, so that the right side of the embryo comes to lie upon the yelk. It is not a little remarkable that so slight a deviation should be so very rare and so frequently accompanied by grave malformations. In cases of transposition there appears to be a strong tendency in many organs to revert to their normal position ; thus transposi- tion is frequently partial. In the Mollusca transposition occurs commonly in some few genera, and has long been considered as a variation ; one species of Whelk is constantly reversed. 18. The trunk of a human foetus with complete transposition of all the viscera. The small intestines have been removed. Mus. Heaviside. 19. An injected and dried preparation of the heart and large vessels, with some of the abdominal viscera of a human adult, in which all the parts are transposed. The pre- paration includes the stomach, liver, spleen, and caecum. Class II. DUPLICITY. Subseries I. IN INVERTEBRATES. Subclass I. Dichotomy. 20. An Earthworm with the posterior third of the body sym- metrically double. Presented by W. Clift, Esq., 1810. Subseries II. IN FISHES. Subclass II. Homologous union. 21. Two specimens, each consisting of two newly hatched Trout united by the posterior portions of the ventral aspect. The single yelk-sac is attached to the lower specimen, showing their origin from a single yelk. Presented by the Duke of Wellington, 1870. 22. Two small Sharks united in the same manner as the Trout DUPLICITY. 5 in the last preparation. The remains of a single yelk- sac (pseudo -placenta) is seen between the pectoral fins. A female Shark was taken by the donor (mate of a vessel) in the Indian Ocean (34 S. lat., 90 E. long.). When brought on deck and cut up, about thirty living young escaped from its abdo- men. The specimen presented lived for two days in a bucket of sea-water. Presented by E. Bestard, Esq., 1866. Subseries III. IN AMPHIBIA. Subclass IV. Heterologous union. 23. A Frog with a small additional anterior extremity springing from the posterior and lateral part of the sternum. This preparation has been placed provisionally in its present position, under the theory that the limb in question is the only developed part of a second embryo. Such is probably the case, but there is too little evidence to justify any decided inference. (See also Nos. 47 and 48.) Hunterian. Subseries IV. IN REPTILES. Subclass I. Dichotomy*. A. Anterior Dichotomy.. Syn. Cephalodidymi, Gurlt. Monstres doubles monosomiens, Geoff: 24. A small English Snake with two heads. The axis is di- stinctly double to about half an inch behind the occipital bone only, although there are traces of duplicity in the ventral region more than an inch further back. Hunterian. 25. A small Snake with two distinct heads and double vertebrae in the anterior portion of the body. One head is slightly lateral and smaller ; its neck is shorter than that of the other. Hunterian. 26. A small Indian Water-Snake (Hydrophis) with two heads. Presented by J. Shortt, M.D., 1866. * See Introduction. 6 ABNORMAL CONDITIONS OF THE AXIS. 27. A small English Snake with two heads. Presented by W. White Cooper, Esq., 1872. B. Posterior Dichotomy. There is no true case of congenital posterior dichotomy in Reptiles in the Collection. The following specimen probably represents an acquired condition, the result of injury and the well-known powers of repair possessed by these animals. 28. A Lizard in which a portion of the extremity of the tail is double. Hunterian. Subseries V. IN BIRDS, Subclass I. Dichotomy. A. Anterior Dichotomy. 29. A foetal Duck with two heads and necks ; the dorsal vertebrae, the trunk, and its appendages are single. Hunterian. 30. A similar foetal Turkey with the skull and vertebral canal open from arrested closure of the neural arches, Presented by Lady Northampton. 31. A similar fo3tal Fowl, in which the neural arches of the head are undeveloped. The brain-membranes are exposed. Presented by Sir W. Elizard. 32. A similar foetal Chick with fusion of the heads, so that the approximate eyes have coalesced into a single organ. The neural arches of the head are undeveloped, and the brains are exposed. The spinal cord is deficient, the vertebral canal containing its membranes only. . Hunterian. B. Posterior Dichotomy. 33. A Chick with the posterior half of the cerebro-spinal axis double. There are four legs, but the wings are two in number. The abdominal parietes are deficient, and the neural laminae are undeveloped in the cervical region. There is a slight notch in the upper mandible, as if a tendency to superior dichotomy had likewise existed. Hunterian. 34. A Duckling with posterior dichotomy of the greater part of DUPLICITY. 7 the spinal column. There are four legs and wings. The median wings are united into a single organ. There is considerable deficiency in the coverings of the abdomen. 35. The posterior part of a Duck affected with slight posterior di- chotomy, laid open to show the pelves and their contents. There are four perfect legs, although two only appear to have been functional. The anus is double. That of the right side is imperforate ; it forms a small nipple-like projection externally, and is connected with the cloaca by an imperforate band. The intestine has three caeca instead of two. Presented by Mrs. Robinson, 1819. 36. The oviduct, rectum, and cloaca of a Fowl with two external openings. The cloaca is bifurcated below. A single oviduct opens into its left side. This specimen is pro- bably from a bird affected similarly to the last but to a less degree. Mr. Tegetmeier had a similar Fowl in which both openings were functional. Presented by Dr. Halford, 1862. 37. Posterior dichotomy of the spinal column in a Chick, with fusion of the soft parts of the median pairs of legs as far as the knee. Mus. Brit. 38. A similar Chick. Hunterian. 39. A Duckling in which there is posterior dichotomy of the axis. The left division of the axis is rudimentary in com- parison with the right, and the legs of the left side are fused to the toes. There are two distinct femora and seven digits ; the condition of the limb is similar to that seen in No. 65. This specimen has been partially dis- sected to show the connexion of the redundant limbs with the spine. Mus. Brit. 40. A Chick with considerable posterior dichotomy of the axis,. accompanied with total deficiency of the beak, mandible, and tongue. The posterior nares are completely exposed. The hyoid bone is not deficient. Unfortunately the tho- racic and abdominal parietes have been removed, so that it is impossible to discover how far they were defective. 41. Posterior dichotomy in a Duckling extending into the cer- vical region, and perhaps involving the base of the skull. The neural arch of the skull is open and the brain is 8 ABNORMAL CONDITIONS OF THE AXIS. exposed. The upper mandible and maxillary bones are entirely deficient, but there is a slight frontal protu- berance. Presented by D. Hanbury, Esq. Subclass II. Homologous union. a. Pleuropagus, Forster. The following preparations exhibit posterior combined with anterior dichotomy ; but there appear to be two axes throughout, although the vertebrae are themselves fused in some part of the spinal column. The condition will be at once understood by comparing Nos. 118 to 121. It is impossible, as has already been stated, to say whether the condition arises from fission or fusion. 42. Twin foetal Pigeons united by the dorsal regions of the spinal column, the median visceral laminae being absent. The right lamina of one bird and the left of the other form the abdominal and thoracic walls. The heads and necks are distinct. The neural arches in the upper part of both vertebral columns are defective. Purchased, 1858. 43. Twin foetal Guinea-fowls similarly united with fusion of the vertebral columns in their upper part. There is also fusion of the head and necks. The median eyes are fused into a single but abnormally large organ. The lower mandibles likewise form a single organ. The neural arch of the skull is open, and the brain and spinal cord are deficient. Presented by E, Belfour, Esq. } 1818. 44. A similar union of twin foetal Ducks. The brain is com- pletely double and without any covering. b. Hypogastrodidymus, Gurlt. The two succeeding specimens almost exhibit the characters of heterologous union ; they, however, probably commenced their de- velopment by homologous union, and have therefore been placed in this Subclass. (See also Nos. 103 and 104, which present a similar condition.) 45. A Chick with the rudiments of a second Chick occupying the pubic symphysis. The rudimentary Chick consists DUPLICITY. 9 of a pelvis, with total deficiency of an axis, and of two posterior limbs fused together above as far as the middle of the femora by the skin and soft parts. Hunterian. 46. A Chick with the imperfect wings and legs of a second Chick attached to the abdominal integuments. Hunterian. Subclass IV. Heterologous union. 47. A Duckling with the remains of a second embryo adhering in the superior fontanelle, which has not been closed. It consists of a kind of atheromatous tumour, partially oc- cupied by a hernia of the Duckling's brain, with a small but well-developed leg and foot growing from it. Hunterian. 48. A Pigeon with a small accessory wing growing from the lower part of the sternum. There is no other trace of a second embryo, and the skin has been reflected to show the union of the limb by muscles and ligament with the sternum. Hunterian. Comparing this specimen with No. 47, and in the complete ab- sence of any other means of accounting for the condition, it has been placed in this series, as it seems probable that the limb may be the remains of a second embryo. (See also No. 23.) Subseries VI. IN MAMMALS. Subclass I. Dichotomy. A. Anterior Dichotomy. * In Animals. Anterior dichotomy in Mammals rarely extends further back than the basioccipital bone ; it occasionally, however, reaches the dorsal vertebrae. In this respect Mammals present a marked contrast to Birds and Reptiles, in which it usually involves some of the vertebrae at least, It is very rare in the human subject. 10 ABNORMAL CONDITIONS OF THE AXIS. a. Diprosopus, Gurlt. Syn. Monocranus, Gurlt. Diprosopus is the term applied to those forms of anterior dichotomy in which fission does not extend to any of the ver- tebrae. This condition often accompanies posterior dichotomy. Examples are seen in Nos. 90 to 94. In its lesser forms it is called Monocranus by Gurlt. 49. A Kitten with dichotomy of the anterior part of the face ; one mouth is very imperfect. There is a single pair of eyes. Hunterian. 50. A Kitten with dichotomy of the head extending further back than in the last, so that there are four eyes. The eyelids of the median eyes have no inner commissures, but are united and bound in a single fissure. Hunterian. 51. A foetal Kitten with more considerable anterior dichotomy. The laminae of the vertebrae and spinal cord are deficient in the lumbar region. Hunterian. 52. The head of a foetal Pig with dichotomy of the anterior part of the face ; the mandible, tongue, and the anterior portion of the maxillary bones are double. There is a consider- able fissure in the palate, from which a fibrous band ex- tends to the united mesial rami of the mandible. A por- tion of skin covered with hair, representing the median cheeks, is lodged in the fissure in the palate. Hunterian. 53. The head of a foetal Pig with considerable dichotomy of the lower, and slight dichotomy of the upper jaw, dissected to show the accessory masseter muscles. The tongue is double ; the other parts are single. This specimen before dissection exhibited only what appeared to be a second mouth in the cheek. 54. An anencephalous foetal Pig with more considerable anterior dichotomy than the last, producing a single median eye. Purchased. 55. The head of a Calf with anterior dichotomy extending as far back as the presphenoid bone. The muzzles are united by a thick fold of integument almost to their extremities. DUPLICITY. 11 There is a single median eye situated behind a triangular opening formed by the fusion of two pair of eyelids. Hunterian. 56. The skull of a similar Calf, in which the fission has extended somewhat further back, so that there are two distinct median orbits. The median malar bones are fused into a single bone j they support a small mass of bone, which articulates by a very imperfect joint with the median rami of the mandibles. The median rami of the mandi- bles are united by suture, and are much thickened and distorted. The base of the skull exhibits a single basi- occipital and a bifurcated basis phenoid with its two median alisphenoids united. The exoccipitals, supraoc- cipital, and temporals are single, except that there are traces of median squamosals. The other bones of the head and face are completely double. 57. A similar skull, in which, however, dichotomy extends as far back as the basioccipital. In this skull there are two supraoccipital and a median external auditory meatus; the periotic bones of the median ear are double ; both faces are distinct and well formed. Hunterian. 58. The brain of a Calf with anterior dichotomy, probably from No. 55. All the parts in front of the pons are double. The pons, medulla, and cerebellum are single. Hunterian. 59. A portion of the brain of a Calf double as far back as the foramen magnum, probably from the same animal as No. 57. It is stated in Hunter's MS. dissections that all the cerebral nerves were double, that the eighth pair were double at their origin, but that the median eighth pair became fused and terminated in their passage through the skull in connective tissue. Hunterian. 60. A portion of the skull and the brain of the Sheep with di- chotomy extending as far back as the basioccipital bone. 61. The tongues, hyoid bones, larynx, trachea, and oesophagus of a double-faced Calf, probably from the same animal as Nos. 55 and 58, dissected. The double hyoid arch has its median cornua distinct, close together, and cartila- ginous. The median pair of tonsils are seen fused to- gether between the two tongues. It is stated in Hunter's 12 ABNORMAL CONDITIONS OF THE AXIS. MS. dissections that there was a third median carotid in front of the trachea,, which divided in the head into two vessels having the usual branches and distribution. Hunterian. b. Dicephalus, Gurlt. In dicephalus the dichotomy extends beyond the base of the skull, and involves the anterior portion of the vertebral column. 62. The cervical and some of the dorsal vertebrae of a dicephalous Calf, in which dichotomy extends as far as the anterior dorsal vertebrae. The atlas and axis of the right neck are unfortunately lost. The dorsal spines below the di- chotomous region are bifurcated. There are two ossinc centres in the bodies of the dorsal vertebrae, a condition seen- in almost all malformations of the spine. A num- ber of small ossinc centres occur between the bodies of the vertebrae at the point of bifurcation. There is a piece of cartilage in the angle of bifurcation. Presented by J. B. Stauffer, Esq., 1867. 63. The brains and a portion of the spinal cord of a dicephalous Lamb. Dichotomy extends to an inch and a half below the foramen magnum. 64. The oesophagus of a dicephalous (?) Lamb bifurcated to within about 4 inches of the stomach. Presented by R. Partridge, Esq. B. Posterior Dichotomy. * In Animals. (This condition is almost confined to quadrupeds, and is very rare in the human fostus. Human foetuses affected with di- chotomy have been placed together at the end of the series : see Nos. 87, 88, and 89.) a. Dipygus, Gurlt. Dichotomy of the posterior portion of the axis is far more common in Mammals than of the anterior portion. There are three distinct forms of posterior dichotomy. In the first the pelvis alone is double and the second axis is wanting ; hence it is doubtful whether such forms should be included in this class. DUPLICITY. 13 It is probable, however, that the axis was originally dichoto- mous, but that development of one portion is arrested at an early stage. Another hypothesis is that the second pelvis originates in the process of repair consequent on an injury to the embryo. Valentin injured the posterior extremity of an embryo and pro- duced this condition. It is impossible with our present know- ledge of the subject to decide on the merits of these two hypo- theses. Without Valentin's experiment analogy would lead us to adopt the former view unreservedly. The term dipygus has been restricted in this Catalogue to such forms. 65. The skeleton of a dipygous Kitten. The axis deviates to the right side, and the laminae of the ver- tebrae are deficient in the lumbar region. The right innominate bone of the right axis and the left innominate bone of the left axis are united by the pubic symphysis ; each bears a perfect limb. The other innominate bones are rudimentary, and their ilia and aceta- bula are fused together. The tuberosities of the ischia of these median imperfect bones are ankylosed with those of the more developed fellow bones. The left femur of the right axis and the right femur of the left axis are fused into a single broad bone with two heads ; this articulates with a single median tibia and two fibulae. There are two perfect feet to this median limb. 66. A dipygous bitch Pup with the abdomen laid open to show the viscera. The innominate bones and additional posterior extremities are precisely like those of No. 65. The rectum bifurcates about an inch and a half from its extremity ; the right portion is blind. The external sexual organs are double. There are two vaginae and two bladders. The right bladder is smaller than the left. The right kidney is very small ; its ureter becomes impervious about a line from its inferior extremity, where it is connected with the left vagina. The left kidney is very large ; its ureter opens into the left bladder. A bristle points to the right kidney. The va- ginae and anus are also marked with bristles. Hunterian. 67. The external and internal generative organs and a portion of the double pelvis of a large Dog, dissected. There is no history of the preparation ; but it is probably from a dipygous animal very similar to the last, except that the posterior 14 ABNORMAL CONDITIONS OF THE AXIS. innominate bones are less developed, so that the median leg was probably either rudimentary or wanting. The accessory innominate bones consist chiefly of the tuberosities and posterior rami of the ischia ; these are united below by os- sified fascia, which extends to the arch of the pubis. There are two penes, urethree, and bladders, and but two testes. Each blad- der has a single ureter opening into its outer side. The right kidney is reduced to a hard fibrous button-shaped mass, about three quarters of an inch in diameter ; the right bladder is much thinner than the left, and its cavity is occupied by a fungous mass of granulations. The muscles of the bulbs of the urethrae arise partly from the additional and partly from the normal pelvic bones. The right prostate is very small, and the urethra of this side is im- pervious where it passes between the pelvic bones. b. Schizorhachis. Under this term all cases of posterior dichotomy of the spinal column have been included, except those in which the mal- formation extends to the head and appears externally, and those already described as dipygus. Dichotomy almost always extends to the occiput, and usually affects the basioccipital bone slightly. A single preparation shows dichotomy of the lumbar region only. a. Unsymmetricdl Schizorhachis. 68. The posterior portion of a foetal Pig, with posterior dicho- tomy of the spinal column commencing in the lumbar region. The right half of the double axis and its limbs are much smaller than the left. This preparation has been dissected to show the viscera. The intestine and stomach are drawn up. There are two uri- nary bladders ; that belonging to the accessory axis has two ureters and two minute kidneys. There is a large suprarenal capsule on the right side. The left axis has only a single, much elongated kidney on its left side. The aorta bifurcates to supply the second axis. /3. Symmetrical Schizorhachis. 69. A foetal Pig with dichotomy of the whole spinal column and four distinct anterior extremities. The thoracic and ab- dominal cavities have been opened to show the heart and DUPLICITY. 15 main arterial trunks. The heart consists of two left hearts united ; there are no pulmonary hearts. Each ventricle gives off an aorta which crosses to the opposite side, so that the heart on the left side supplied the right inferior extremities, and that on the right the left. The carotids, two in number, are given off together from the arch of the right aorta. The trachea is single. The lungs are very small and imperfect ; they probably consist of a single pair. The vessels of the right heart are injected. The palate is deeply cleft. Hunterian. 70. A similar foetal Pig with the skull and spinal canals laid open to show the brain and cords. The adjacent lateral tracts terminate by joining each other, the outer ones alone pass to the brain. Hunterian. 71. A similar but anencephalous foetal Pig. The base of the skull is exposed ; the cerebral nerves are, however, quite distinct at their point of exit from the skull. Hunterian. 72. A foetal Mole with dichotomy of the whole spinal column. Hunterian. 73. A foetal Puppy with dichotomy of the spinal column. The median pair of anterior extremities are represented only by a tubercle. It is probable that the dichotomy does not extend into the upper part of the cervical region. Hunterian. 74. A foetal Kitten with dichotomy of the axis and four complete anterior extremities. Hunterian. 75. A similar Kitten. Hunterian. 76. The skeleton of a similar Kitten, in which the occiput is slightly cleft, so that there are two exoccipitals. This specimen belongs strictly to the following subdivision, Schizocotis ; it is probable, however, that some of the preceding specimens are similarly affected. It has therefore been thought expedient to separate those forms only as Schizocotis in which the cleft condition of the skull is apparent externally. These divisions are not separated by any distinct lines of demarcation and are purely artificial. The manner in which the median ribs are de- pressed and united in animals affected with dichotomy is well seen in this preparation. Presented by J. Burton, Esq. 16 ABNORMAL CONDITIONS OF THE AXIS. 77. A similar foetal Kitten, with the skull and spinal canal opened to show the brain and the double medulla and cord. Hunterian. 78. A similar Kitten, with the thorax and abdomen opened to show the viscera. There is slight anterior dichotomy affecting the lower lip, mandible, and tongue, with fis- sure of the palate. The alimentary canal is double from the lower portion of the ileum downwards. Hunterian. 79. A similar Kitten, with the thorax and abdomen opened and the viscera raised to show the kidneys, of which there are but two, the urinary bladders, and hypogastric arteries. Hunterian. 80. A similar Kitten, in which the median pair of anterior ex- tremities are united as far as the carpus. The upper lip and palate are deeply cleft. Hunterian. c. Scliizocotis*. Under this term those forms have been classed in which, in addition to complete dichotomy of the trunk, dichotomy of the posterior part of the skull is apparent externally. A pair of more or less developed external ears exist between the two axes, exhi- biting variable degrees of fusion with one another in a manner analogous to that seen in extreme cases of anterior axial defi- ciency. 81. A foetal Rabbit with slight dichotomy of the base of the skull. The approximate external ears are of small size ; they are very defective, and are fused together. Hunterian. 82. A foatal Rabbit with somewhat more considerable dichotomy of the base of the skull. There are a distinct pair of ad- ditional ears. The roof of the skull has been removed to show the extent of the dichotomy. This was one of a litter of six, the remainder were normal. Presented by C. R. Bree, M.D., 1871. 83. A foetal Cat with dichotomy extending to the base of the skull, and involving only part of the basioccipital bone. * Kom, the occiput. DUPLICITY. 17 The additional external ears are very defective and are fused together. Hunterian. 84. A similar dichotomous foetal Pig. d. Schizocephahis. * Syn. Iniops, Geoff'. Synkephalus asymmetros, Forster. Janus -Bildung. This condition depends, apparently, on an extension of pos- terior dichotomy still further forwards, so that it involves the greater part of the base of the skull. An accessory face is formed in the angle between the two axes. This face is deficient in its axial parts, and hence it exhibits the phenomena of axial arrest or deficiency, as fusion of the eyes and ears, agnathia, &c. (See Class VI.) 85. A foetal Pig with dichotomy of the axis extending forward into the basisphenoid region. The accessory face has the eyes fused together as far as the edges of their irides. There is a frontal proboscis above, and a pair of closely approximated ears below; a condition precisely similar to that seen in cases of epencephalic deficiency, i . e. defi- ciency of the epencephalic region and all the parts an- terior to it. (See Nos. 187 to 190.) Hunterian. 86. A similar foetal Pig with the eyes of the accessory face di- stinct, but so obliquely placed that the fissures of the eyelids are almost vertical. Presented by J. Winterbottom, Esq. ** In the Human foetus. a. Schizorhachis. Syn. Dipygus, Forster. Deradelphus, Geoff. 87. A female Human foetus with complete dichotomy of the spi- nal column, probably affecting the basioccipital region, although there is no external indication of dichotomy extending to the skull. There are two perfect trunks united by the thorax. One of the right arms is distorted at the wrist. Hunterian. 18 ABNORMAL CONDITIONS OF THE AXIS. b. Schizocotis. Syn. Synkephalus asymmetros, Forster. Janiceps, Geoff. Janus- Bildung. 88. A female Human foetus with posterior dichotomy extending into the base of the skull, probably as far forward as the posterior part of the basisphenoid. There is a pair of well-formed external ears behind fused together below, with a single meatus between them. A small circular fossa above these, with a depression in its centre from which a minute tuft of hair is growing, probably represents a rudimentary Cyclops-eye. Mus. Brit. 89. A similar female Human foetus with the dichotomous condi- tion extending a little further forwards, so that a trans- verse fissure corresponds to the position of a Cyclops-eye. Brought from the East Indies in 1805. Presented by Sir E. Home, Bart., 1807. C. Antero-posterior Dichotomy. Syn. Hemipagus, Geoff. Anterior and posterior dichotomy often coexist in the same embryo. In animals there can be no doubt that this condition is distinct from Homologous union', when it is extreme, how- ever, as in No. 94, a human foetus, it is impossible to deter- mine to which Subclass the phenomenon should be referred*. 90. A foetal Kitten with complete dichotomy of the trunk, and a slightly double condition of the tongue and mandible. Hunterian. 91. A similar foetal Kitten with more considerable dichotomy of the mandible and tongue, accompanied by cleft palate. 92. A similar Kitten with the median anterior limbs fused as far as the carpus. 93. A foetal Pig with posterior dichotomy (Schizorhachis) com- bined with anterior dichotomy of the lower jaw and tongue. There is a considerable cleft in the palate con- nected with the median rami of the jaw by a fold of mucous membrane. (No. 52 exhibits a similar condition.) Hunterian. * See Introduction. DUPLICITY. 19 94. A female Human foetus with posterior dichotomy (Schizo- rhachis) combined with anterior dichotomy, producing considerable doubling of the face. There are four eyes, but the inner ones are contained in a single orbit. The axes diverge, both in front and behind, from a point in the basisphenoid bone. Hunterian. Subclass II. Homologous union. A. Prozygosis*. Syn. Somatodidymus, Gurlt. Monstres Syncephaliens, Geoff. Synkephalus symmetros, Forster. Janus-Bildung. In Prozygosis there are two perfectly distinct axes united at their anterior extremities, so that at an early stage there must have been two distinct embryos. The foetuses arising from such embryos are united by the visceral arches and laminae above the umbilicus. The right side of one axis unites with the left side of the opposite one. 95. Female Human twins, about the seventh month of gestation, united by prozygosis. The faces are opposite to each other, and at right angles to the normal position; they are much flattened, the eyes are closely approximated, and the ears are very low down. The two embryos were pro- bably distinct at first, and became united by the fusion of the anterior extremities of the investing mass of each with that of the other, so that the trabeculse became united in the same manner as the other facial arches are joined, the right arch of one embryo being fused with the left arch of the other. The following history is recorded: "Labour lasted forty-eight hours, delivery followed without instruments. The mother, a negress, had convulsions. The foetuses lived five minutes, a very unusual occurrence in such cases. There was one funis and one placenta." Presented by T. Sharp, M.D., 1820. 96. A similar twin-birth about the sixth month of gestation, * Upo before, vyow to unite. c 2 20 ABNORMAL CONDITIONS OF THE AXIS. except that the two faces are not perfectly symmetrical, the mouth of one being a small circular opening. Mus. Brit. 97. Twin foetal Hares united by the anterior extremities of the axes. The anterior portion of each axis has been arrested in development, so that the faces exhibit the characters of epencephalic deficiency, cyclopia, agnathia, fusion of the ears, &c. Presented by Sir W. Blizard, 1811. 98. Twin foetal Hares in a similar condition. There is a frontal proboscis on one face. B. Opisthozygosis*. Syn. Hypogastrodidymus, Gurlt. Ischiopagus, Geoff. In Opisthozygosis two distinct axes are united at their posterior extremities, or at some point near their posterior extremities. The embryos remain completely separate above the umbilicus, but unite below by the visceral laminae. One foetus is generally very defective. Sometimes the axes are bent at right angles, in opposite directions, at the point of union. Opisthozygosis is very rare in animals, and the pelvic bones and posterior limbs only of the second axis are usually developed in them, as in No. 103. A similar condition in birds is seen in Nos. 45 and 46. 99. Human female twins united by Opisthozygosis about the sixth month of gestation. The viscera had been re- moved and the spinal columns and pelvis much damaged by a hasty examination. The viscera were fortunately preserved, and are seen in No. 100, The sacrum of one side only has been developed. It is situated at right angles to the two spinal columns, which are placed end to end, the bodies of the vertebrae being united without any perceptible break. The sacrum is entirely cartilaginous, no traces of the second sacrum exist. The pelves are otherwise perfect ; but the right in- nominate bone of one foetus is united with the left in- nominate bone of the other, and vice versa. The ilia are united to the lumbar vertebras by elongated transverse behind, wy6a> to unite. DUPLICITY. 21 processes. The upper pair of limbs (in the present posi- tion of the preparation) belong to the upper and the lower pair to the lower foetus. Each foetus may be considered as having its pubic symphysis open and its pubic bones united with those of the other. The axial parts posterior to the point of union in the upper foetus turn to the right, those of the lower to the left side of the preparation. The upper foetus is well formed, except in the pelvic region. The lower foetus is very imperfect. Its face is misshapen, and the upper cranial bones are altogether wanting. The superior extremities are thick and defec- tive, and the fingers are very short, owing to the imperfect condition of the terminal phalanges. The nails are scarcely perceptible. No history has been preserved. 100. The viscera and generative organs of the same. The viscera of the upper foetus are seen upon the right hand, those of the lower upon the left-hand side of the preparation. The heart, liver, and lungs of the upper foetus are nor- mal : the development of the intestines seems to have been somewhat arrested ; they terminate in a very capacious thin-walled rectum, which was much stained with me- conium. There is a small anal opening marked by a white bristle; it is probable, however, that the dilation of the rectum arose from atresia at an earlier stage. The heart, lungs, and liver of the lower foetus are much smaller ; the intestines are about equal in development to those of the upper one; there is much less enlargement of the lower part of the bowel, but it opens into the en- larged intestine of the upper foetus near the anal opening. The most remarkable character in these viscera is that they do not exhibit " situs mutatus." The kidneys in both foetuses exhibit the condition known as horseshoe kidneys ; they unite below with their fellows across the mesial line. The four ureters open into a single large urinary bladder, which is laid open ; the openings of the ureters are marked by black bristles. The urethra is likewise laid open. The uteri are both equally developed ; both vaginae are well formed, but they both open with the urethra on the right (upperside in this preparation) ; their openings arc marked with black bristles. The labia niajoru, ininora, and clitoris arc well formed on this side. 22 ABNORMAL CONDITIONS OF THE AXIS. The external generative organs of the other side are very ill-formed, and are only connected with the internal organs by the right round ligament of the uterus of the lower foetus. There is no indication of either urethra, vagina, or anus on this side. There is a small swelling, about as large as a pea, at the anterior extremity of the left labium. 101. Human female twins, about the sixth month of gestation, united by opisthozygosis. The second foetus is exces- sively malformed, and possesses neither heart nor brain. The axes are united near the lower part of the dorsal vertebrae by ordinary intervertebral cartilage and liga- ments, exactly like those between the consecutive verte- brae. The remainder of both vertebral columns is want- ing as far as the sacral vertebras. There is a large sacrum on the left side, placed at right angles to and behind the united vertebral columns. The sacrum on the right side is very defective, consisting of a mere ring of bone articu- lated with the base of the left sacrum by cartilage and ligament. The neural arches of the vertebrae are open behind at the point of union between the sacra and vertebral columns. The laminae of both columns form a conti- nuous series with those on the adjacent sides of the sacrum on the left side, and of the rudimentary sacrum on the right ; a large lozenge-shaped opening is thus left in the neural canal. The neural canal of the sacrum is continuous with that of the vertebrae, and this makes a sharp bend backwards from either axis to meet the sacral neural canal. The following facts were recorded by Drs. Marcet, Roget, and Mr. Lawrence from an examination made when the foetus first arrived in England : " The inter- val between the lamina of the vertebra was occupied by a strong membrane ; on the division of this, the medulla spinalis was seen running across from one spine to the other, and distributing its nerves laterally to the two lateral pelves/' From a careful consideration of the above conditions, it appears that the axes of two embryos came into contact at a very early period of development, so that the neural cords arid the proto- DUPLICITY. 23 vertebrae in the dorsal regions were developed in a continuous series ; and the caudal extremities of the axes became displaced and partially absorbed, so that the axial portion of the sacrum has been developed from the remains of one of these displaced axes. The neural arches appear to have followed the same law of deve- lopment as the visceral arches at the point of union between the foetuses, those of the one axis tending to unite with those of the other instead of with their fellows. A comparison with other specimens of a similar malformation renders its probable that the upper pair of legs and the correspond- ing pelvic bones were developed from the visceral laminae of the upper, and the lower pair from those of the lower foetus. The thoracic viscera of the upper foetus are normal. The aorta in the abdomen turns off to the left pelvis and gives off a pair of large hypogastric arteries, of which the upper is the larger. At the point where the aorta turns off to the left it gives origin to two large vessels : one runs straight into the thorax of the lower foetus and terminates in two innominate arteries, the other supplies the right pelvis and lower limbs. The whole of the anterior walls of both foetuses are extremely de- fective. The ribs of the lower foetus are developed behind only. A slip of muscle crosses its body -cavity from tjie left axilla to the right pubis. Its thorax was chiefly occupied by a large sac, the greater part of which has been removed with the viscera, and is seen in the next preparation. This sac communicated with the intestines above and with the mouth below. It is referred to in M. Maunoir's original description of this monster (Med.-Chir. Trans, vol. vii. p. 257) as a " kind of cloaca," of which he says, " On opening the cloaca it was found to contain the rudiments of a lower jaw and of a tongue, which were immersed in meconium, with which the cavity was filled." The cranial and facial bones are only represented, in the inferior head, by irregular masses of cartilage. There is a very rudimen- tary and misshapen external ear. The brain was represented by a large cyst filled with blood, a condition usual in anencephalic con- ditions : this was removed before the foetus was sent to England. The following history is recorded (Med.-Chir. Trans. I.e.}: " A girl of 16 or 17 gave birth to this foetus in Geneva ; it lived a few minutes. There was no difficulty in the labour ; the perfect head was born last." Presented by the Medico- Chirurgical Society, 1816. 102. The abdominal viscera of the same, except the liver, and the kidneys which were contained in the left pelvic por- tion of the twin-birth ; these parts had been removed. 24 ABNORMAL CONDITIONS OF THE AXIS. The following viscera are seen in this preparation : The stomach of the superior foetus is displayed at the upper part of the mica, with the duodenum, the remains of the liver, the jejunum, and ileura. Near the middle of the latter, and connected with it by about three quarters of an inch of intestine, is a portion of the large cloacal sac from the inferior foetus. The accompanying description of the liver occurs in M. Maunoir's paper (I.e.): " An enormous liver covers the whole intestinal mass, and appears through the transparent membranous abdominal wall, between the laminae of which a single umbilical cord [probably the umbilical vein only is here alluded to] passes in a serpentine course and enters the liver." The liver, anterior abdominal wall, and cord have unfortunately not been preserved. The ileum bifurcates about an inch from its inferior extremity and opens into two distinct caeca, each having a short vermiform appendix. The large intestines are double : that on the right side of the preparation belongs to the right side of the monster ; it is opened to show its blind termination above the uterus. The left large intestine belonged to the left inferior portion ; it termi- nates in an anus. The kidneys of the right side are preserved ; they are adherent throughout their entire length. The left kidneys are wanting, but are stated to have had but one ureter between them. The blad- ders, urethras, and external sexual organs on both sides are normal. There is a uterus on each side, the right one being considerably larger than the normal foetal uterus. Presented by the Medico- Chirurgical Society. 103. The skeleton of a half-grown female Cat, with an imperfect accessory pair of innominate bones occupying the pubic symphysisj an accessory pair of limbs are attached to them. Although the axial parts of this pelvis and all the remainder of a second animal are absent, there can be little doubt but that these bones were developed from a second embryo. If the axis had been developed an opisthozygous twin monster would have resulted. The second pair of limbs are short, distorted, and ankylosed to the pelvis, probably from disuse. Their patellae are absent. The Cat was caught in a trap in a wood, where it had been living in a wild state. Presented by W. B. Tegetmeier, Esq.., 1867. 104. The bones of the pelvis and inferior extremities of a Sheep, with the pelvic bones and posterior extremities of an im- DUPLICITY. 25 perfect twin similarly attached. In this preparation the parasitic limbs are fused as far as the metatarsus. A comparison of these limbs- with the dichotomous limb of a monkey, No. 307, shows the difference between malfor- mation from fission and fusion in a marked manner. Hunterian. C. Parazygosis*. In Parazygosis twins are united, by the visceral laminse of the trunk, above the umbilicus. They are usually placed face to face, and have the laminse on each side equally developed ; rarely they are placed side by side, and have the laminae of the adjacent sides very deficient. Parazygosis is extremely rare in animals, although it is the commonest form of duplicity in the human foetus. a. Xiphopagus, Geoff. The least degree of parazygosis. The union is by the xiphoid cartilages of the sterna and by the abdominal walls, above the umbilicus. 105. A wax model of the band of union of the " Siamese Twins " made in 1830, when they were 19 years of age. In child- hood the band was proportionately much larger and shorter, so that the twins were much closer together. The xiphoid cartilages of the sterna pass across the upper edge of the band. The condition of these twins at the age of 19 and their history is given in the Phil. Trans. 1830, p. 117. Presented by G. B. Bolton, Esq., 1830. b. Thomcopagus, Forster. Syn. Sternopagus, Geoff. In this form the thoracic cavities are united by the visceral laminse ; the foetuses are placed symmetrically face to face. 106. Female Human thoracopagous twins, 3 inches long (about the third month of gestation) . Presented by Sir E. Home, Bart., 1804. 107. A similar twin-birth, 3 inches long (about the third month of gestation) . The relation of the foetuses was disturbed when this specimen was first put into spirit, so that it docs not apparently conform with by the side of, ?vy6w to unite. 26 ABNORMAL CONDITIONS OF THE AXIS. the above description of thoracopagus. Naturally the foetuses would face each other in this and in the preparations Nos. 109 and 110. Presented by W. Parry, M.D., 1870. 108. A Human female thoracopagous twin-birth, 8 inches long (probably about the end of the fourth month of gesta- tion). Presented by Sir PF. Blizard, Bart., 1811. 109. A Human female thoracopagous twin-birth, about 10 \ inches long (probably at the end of the fifth month) . Presented by Sir Joseph Banks, Bart., 1819. 110. A Human female thoracopagous twin-birth, about 12 inches long (about the end of the sixth month of gestation) . Hunterian. 111. Human female thoracopagous twins about full time of ges- tation. The deficiency of the anterior abdominal wall above the umbilicus is very considerable, the viscera being covered by membrane only. Hunterian. 112. A similar twin-birth, with the visceral cavities laid open to show the disposition of the viscera. The diaphragmata and pericardia are united. The hearts are quite distinct. The livers are completely fused: there are, however, two transverse fissures and two ductse venosse. The in- testines of the two communicate by a short capacious gut near the lower part of the ileum. The single cord has been laid open, and is seen to contain two distinct umbilical veins (injected) and five umbilical arteries, one foetus having a small additional one. TKe foetus on the left-hand side of the preparation has the disposition of the viscera reversed. The following is the history of the birth : The first foetus pre- sented by the face and the head was not expelled until about four and twenty hours after the commencement of labour ; the abdomen of the second child was then discovered. The feet of the first and afterwards those of the second child were then brought down, and so the mother was delivered, but not without considerable difficulty. In five labours this woman had malformed births three times, these twins, a child with the feet growing from the nates, and a child with undeveloped forearms, so that the hands appeared as if growing from the extremity of the humerus ; all were still-born. The above particulars are extracted from a letter from Mr. G. W. Friend to the Curator of the Hunterian Museum. Presented by G. W. Friend, Esq., 1815. DUPLICITY. 27 113. Human thoracopagous twins of small size, with the viscera removed to show the union of the thoracic and abdominal parietes from within. The disposition of the ribs is well seen in this preparation. 114. The heart and lungs of the same. The heart is formed of the united hearts of both foetuses ; it is much elongated in the direction of a line joining the two spinal columns. There are two di- stinct ventricles, and a single auricle extending the whole length of the upper part of the ventricles. There is a rudimentary auricular septum. There are two auriculo- ventricular openings, each guarded by a bicuspid valve. The cavities of the heart have been laid open. The ventricle on the right-hand side of the preparation has two arterial openings at its base, an aorta and a pulmonary artery, the latter indicated by a blue glass rod. The ventricle on the left-hand side has a single artery or aorta, -which gives off three pulmonary arteries near its origin. This vessel is laid open to show the orifices of the pulmonary vessels. There are four lungs, two on each side of the preparation. Neither set exhibits situs mutatus. 115. The livers, stomachs, and duodena of the same. The livers are united along their whole anterior edges. The sto- machs and spleens are seen one on either side of the liver. The gall-bladder and the ducts of each liver are distinct. The duodena open into a common pouch just below the entrance of the gall-ducts. The intestine was single from the confluence of the duodena to the termination of the jejunum. 116. The lower portion of the small and the commencement of the large intestine of the same. The jejunum terminates in a large pouch, on the extreme left of the preparation, from which two ilea arise. There are two caeca, and each has a distinct vermiform appendix. The large intestine was completely double. 117. Human female thoracopagous twins about the end of the sixth month of gestation. One of the foetuses has syreni- form fusion of the posterior limbs, and there is complete ectopia of all the abdominal viscera. The thoracic cavities have been opened to show the hearts, which are very ab- normal ; one is above the other. The upper heart consists 28 ABNORMAL CONDITIONS OF THE AXIS. of an auricle and ventricle. The ventricle gives an aorta to either foetus, and is fused with the base of the ventricle of the lower heart. The lower heart has two auricles. The apices of both ventricles are turned towards the front of the preparation. . The specimen was so brittle that the exact distribution of the vessels could not be made out. c. Pleuropagus, Forster. Syn. Dicephalus, Gurlt. Monstres doubles Sysomiens, Geoff. In Pleuropagus two axes are adherent side by side. Such ab- normal twins have hitherto been called dicephalus, from their external resemblance to dichotomous conditions of the anterior extremity of the axis. In these forms, however, the whole axis is double. They are transitional between anterior dichotomy and parazygosis. The median limbs are frequently fused toge- ther, and are sometimes reduced to mere tubercles. 118. A Human pleuropagous twin-birth, about the end of the third month (length 4| inches), with the mesial (posterior) arms and legs fused together as far as the carpus and tarsus. It is apparently female, but the organs of generation are very imperfectly formed. This specimen is transitional between thoracopagus and the more marked forms of pleuropagus. Purchased, 1870. 119. Human male pleuropagous twins. The median (posterior) arms form a mei*e tubercle upon the back. There are no median legs, although there are two axes even to the ex- tremity of the sacrum. The median innominate bones are absent. 120. The bones and ligaments of the united mesial arms of an exactly similar foetus. A small portion of the broad sternum, formed by the union of two sterna, supports a pair of clavicles closely pressed together; distinct and flattened in front, but united behind. These articulate with the two acromia of a very remarkable double scapula, and are also united with the glenoid cavity by ligament, a piece of cartilage intervening. The scapula is symmetrical, and presents two spines and two acromia ; one of the latter has been cut through and turned back to show the manner in which DUPLICITY. 29 the glenoid cavity is articulated with the clavicles. The cartilage already mentioned, situated between the clavicles and glenoid cavity, is the only rudiment representing the anterior median limbs. 121. The viscera of the same; these are double, but those of the right foetus are considerably smaller than those of the left ; the latter are reversed. The hearts were situ- ated in distinct pericardia. The heart of the left is three times the size of that of the right foetus. The latter gives off a small aorta, which joins the descending aorta of the left foetus just below its arch. The livers are in- timately united ; the oesophagi, stomachs, and duodena are distinct as far as the orifice of the bile-duct, where the intestines unite in a sacculate dilatation ; below this point the intestine is single but reversed, the caecum being on the left side. d. Ischiopagus, Forster. Syn. Pygodidymus, Gurlt. Pygopagus, Geoff. In Ischiopagus the twins are united by the lower extremity of the axis only, and are placed back to back, so that the visceral cavities are distinct. Judith and Helena, " The Hungarian Sis- ters " (Phil. Trans, vol. 50, p. 31 1) , and Millie-Christine, the "Two- Headed Nightingale," exhibited in London in 1871 (Lancet, 1871, i. p. 725), are examples. No specimen occurs in the Museum. 122. A wooden model representing two ischiopagous infants. The anus is represented as single, and the vaginae are united at their posterior commissures, the usual disposition of these parts in such malformations. Subclass III. Homologous union with dichotomy. The so-called triplex human foetus described in the ' Atti delP Accadem. Gioen. 5 t. viii. p. 203, is undoubtedly an example of pleuropagus combined with anterior dichotomy of one axis. Several cases are recorded by Gurlt as having occurred in animals. 30 ABNORMAL CONDITIONS OF THE AXIS. Subclass IV. Heterologous union. A. By Impaction. Syn. Heterodidymus, Gurlt. A second embryo may become wedged in between the visceral arches or laminae of another before they unite. In such cases the impacted foetus usually exhibits great deficiency,, and is called a parasite. Most frequently it has neither a heart nor a head ; sometimes it becomes converted into a more or less amorphous tumour, with one or two organs only developed in a normal manner. The supporting foetus is called the autosite. a. Between the lateral halves of the sternum. Syn. Thoracopagus Heterodelphus, Geoff. The upper part of the parasite is wedged in between the thoracic laminae of the autosite., and lodged in the middle of a fissured ster- num. The parasite is usually very defective j the axis may be en- tirely wanting, the limbs only being developed. More frequently there is a rudimentary abdominal cavity in the parasite, commu- nicating with that of the autosite above the umbilicus, as in ordi- nary thoracopagus. The abdominal cavity of the parasite is some- times distinct from that of the autosite, and has a separate um- bilicus. A perfect series of transitional forms exist between this condition and ordinary thoracopagus ; hence it has been called parasitic, or heterodelphous thoracopagus. 123. A female foetal Pig with a headless acardiac parasite united to the thorax and abdomen. The cervical region of the parasite is attached to the sternum of the autosite. The body-cavities of the two are continuous. The parasite has a single large kidney, a urinary bladder, and a pair of hypogastric arteries. There is also a small piece of intestine connected with that of the autosite by a long, narrow gut. The abdominal cavities have been laid open to show their continuity. Hunterian. 124. A foetal Kitten with a similar parasite. Hunterian. 125. A foetal Kitten with a parasite attached to the sternal region. The body-cavity of the parasite is very small and distinct from that of the autosite. There are two distinct cords DUPLICITY. 31 for a short distance at least from the umbilicus. The parasite appears to have no spinal column ; but the pos- terior limbs are well developed, and the anterior limbs are small but clearly recognizable. Presented by E. Self our, Esq. 126. A similar specimen, in which the anterior extremities of the parasite are fused with the left anterior extremity of the autosite. 127. A similar specimen, except that the anterior extremities of the parasite are wanting. 128. A specimen similar to No. 125, with the body-cavities laid open to show that they are quite distinct. That of the parasite contains a single large kidney and a urinary blad- der : it has no alimentary canal. Hunterian. 129. The skeleton of a similar Kitten and parasite. The ster- num of the autosite is divided by a wide oval fissure, in which the four limbs of the parasite are seen. The pa- rasite has no vestige of an axis, unless a band of ligament in the centre of the sternal fissure represent its remains. The anterior pair of parasitic limbs are fused as far as the carpus. The Kitten was one of a litter of three, the others were normal. 130. A clay model of the Chinese lad Ake, aged 16, with an acephalous parasite attached to the lower part of the ster- num. The model was made from memory by a Chinese artist. The following extracts from a letter from J. Li- vingstone, Esq., Surgeon to the British factory at Hong Kong in 1804, give the history of the case : " Ake was born with another male child of nearly the same size united to the pit of his stomach by the neck, as if his brother had plunged its head into his breast. The mother died from the effects of the labour. " Since birth the parasite has not increased much in size. The shoulder-bones are remarkably prominent. Here the model is faulty, since it presents the roundness of infancy ; but all the plumpness had disappeared from the original, and the bones seem only covered with skin. The manner in which the thighs appear is quite happy; but the feet, particularly the left, are not sufficiently clubbed. In the original the feet and toes are less perfect than in the model ; the toes adhere, and one or two are wanting. 32 ABNORMAL CONDITIONS OF THE AXIS. " I have the authority of Lieut.-General Wood for stating that the trunk and neck measure 11 inches, and the longest limb 13 inches. " The attachment of the neck of the parasite admits of a semi- rotatory motion, and Ake shows that his brother's arms can bo moved freely. The thighs and legs remain stiffly bent, the femora being ankylosed to the innominate bones and tibia. The genital organs are too perfect in the model, since no vestige of testes and very little scrotum can be seen in the original. The penis is, how- ever, large in proportion, with the glans about half covered by the prepuce ; it was subject to occasional erections. The kidneys seem to perform their function perfectly ; the anus is wanting. Ake is now about 4 feet 10 inches high, of feeble frame and sickly ap- pearance. Except in the incumbrance above described, he is in all respects perfectly formed. Ake's respiration is commonly labo- rious ; to relieve it, he frequently supports the parasite with his hands; his pulse is commonly quick and small. Mr. Gomez felt the pulsation of the carotids in the neck of the parasite di- stinctly ; he also felt feeble pulsation at the wrists." The condition of Ake, as far as can be judged from the model, seems precisely the same as that of the Kittens, Nos. 124 to 128. Presented by H. L. Thomas, Esq., 18.22. b. Impaction between the facial arches. In such cases the palate is most frequently the seat of impac- tion, and the parasite is modified excessively. 131. The injected head of a Human foetus with a large lobulated vascular tumour, the remains of a second foetus, growing from the median fissure of the palate, which has been kept open by it. The tumour projects from the mouth, which it dilates considerably. It is adherent to the right commissure of the lips, and entirely invested the superior maxillary bone of the foetus, which has been removed and is seen in No. 133. The lobulated tumour presents a widely extended mouth in front. A piece of purple glass rod is placed in its cavity, extending be- tween the commissures of its lips. A long tongue- shaped projec- tion is seen in the mouth-cavity ; but it is covered with lanugo, so that it does not probably represent the tongue. The lips and alveoli are very distinct ; they are divided into two lateral por- tions by large lobules of fatty tumour. A single nostril, marked by a blue glass rod, appears above the left half of the upper lip ; DUPLICITY. 33 at the inner side of the nostril is a deep fissure, probably the re- mains of the nasal cavity ; this fissure is marked by a purple glass rod. The left upper alveolus has been exposed by the removal of the giim, and is very distinct. One of the largest of the fatty lobes, which make up the bulk of the tumour, has been cut through to show its structure. It consists of firm vascular fat with an atheromatous centre. A small cyst appears at its upper part. On the right side there is a piece of adherent placenta, and just below it is a loose, pendent, lobulated mass about an inch and a half in diameter. As one of its lobes felt very hard it was opened, and was found to contain a compact mass of bones, fifty-nine in number (see No. 132). The skin of the tumour is soft, vascular, and covered with lanugo. The lobe which contained the bones presents three indistinctly separate hard white papilla?, something like aborted digits. The most remarkable point in this specimen is that lips and alveoli only are well developed upon the tumour, as if its position had determined the nature of the part developed. There can be no reasonable doubt that the tumour consists of the remains of a second embryo. 132. Fifty-nine ossicles from the tumour in the last preparation. They are most complex in form, and were closely packed together. There is but one which resembles any normal bone, the first of the series ; it appears like the lamina of one of the cervical vertebrae. 133. The superior maxillary bone and a portion of the malar bone from the same, taken from the right side of the tumour. These belonged to the foetus and not to the pa- rasite growth. It is normal, although it supported a por- tion of the tumour. B. By Inclusion. Syn. Cryptodidymus, Ourlt. Fo3tus in Fcetu. Sometimes instead of a second embryo becoming impacted in the visceral arches of another, it becomes enclosed within its ab- dominal cavity. The included embryo in. these cases is contained in a cyst, and connected with it by an imperfect funis. Under these circumstances it may live and grow for many years. It is always excessively defective and much deformed. Both the including subject and fostus arc usually male. 34 ABNORMAL CONDITIONS OF THE AXIS. It is probable that such included foetuses owe their origin to very nearly the same conditions as those which give rise to other forms of doubling. It is not easy to understand how a second ovum could enter the body-cavity of an embryo, whilst there is no difficulty in understanding how a second embryo on a common yelk could be so included. The cyst under such circumstances would owe its origin to a portion of the common amniotic sac, which the included embryo must necessarily carry before it. It is true no connexion has been observed between the cyst and the umbilicus ; but all things considered, the above is the least impro- bable means of accounting for the phenomenon. The disappear- ance of a portion of the amnion in several years is by no means inexplicable, especially when it is remembered that the membrane must have been extremely thin at the time of its induplication. 134. A portion of a cyst (which contained the foetus No. 135) from the abdomen of a well-formed male child aged be- tween 9 and 10 months. The preparation includes a por- tion of large and small intestine of the child. The case is described by Mr. Gr. W. Young in the ' Med.-Chir. Trans.' vol. i. p. 234. The cyst is recorded to have contained 78 ounces of fluid, and to have discharged a portion of its contents several times into the peritoneal cavity ; it is further stated to have been placed between the layers of the transverse mesocolon. The same thing was also believed in M. Duptiytren's case*; but much difficulty arises in the explanation of the phenomenon if such really be the fact. In the present instance it will be seen that the mesentery is likewise adherent to the cyst, and the whole mass is so matted together that it would be impossible to determine whether the cyst is between the layers of the mesocolon or not ; it is much more probable that the cyst was originally placed between the mesocolon and mesentery. The portion of the cyst which has been preserved consists of a number of layers, a fact quite in consonance with the opinion that it was originally formed by an induplication of the amniotic sac. It is very thick, and presents a villous surface within. The upper part of the cyst, which was covered by the omentum, has not been preserved. It is stated to have been very thin and transparent. Presented by G. W. Young, Esq. 135. The imperfect foetus from the same, divided vertically to * Bulletin de la Soc. de la Facultc de Med. Paris, an 13,no. 1, p. 4. Himly, Foetus in Fretn, p. 18. DUPLICITY. 35 show its internal structure. It has no head, its trunk is very much curved, and possesses four misshapen limbs. It was connected with the cyst by a large funnel-shaped umbilical cord, which contains a coil of intestine. Mr. Young states that " when the foetus was taken from the cyst it was covered with sebaceous matter, and when this was re- moved, it appeared as rosy and healthy as if it were alive." At the upper extremity of the trunk a fibrous mass is seen with a portion of the cyst adherent to it ; this is said by Mr. Young to have been " of a dark-red colour when first taken from the cyst, and abundantly supplied with blood." It is exactly similar to the mass usually representing the brain in anencephalous foetuses. That part of the foetus which, corresponds to the frontal region bears a narrow line of fine hair upon it ; this forms a long lock on either side. The vertebral column consists of eleven blocks of bone, re- presenting as many vertebral centres. The posterior aspect of these is covered by a membrane ; there are no remains of the spinal cord, and no traces of laminse. The skin on either side of the vertebrae is covered with short fine black hairs. The sacrum is rudimentary, and entirely formed of cartilage. One of the ver- tebral bodies in the dorsal region seems also to be entirely formed of cartilage. The vertebral column is surmounted by several masses of bone and cartilage, which probably represent the base of the skull and facial bones. The axis is doubled almost at right angles in the dorsal and lumbar regions. A small opening, in which a bristle is inserted, is seen in the mesial line at the most anterior part of the foetus ; it is apparently a vessel, probably a median carotid. In front of the hair, at the anterior part of the foetus, is a frontal proboscis, considerably enlarged and perforated at its free extre- mity : it is extremely similar to the same structure in cases of cranial arrest. (See Nos. 162 et seq.) The body-cavity is not divided by any diaphragm, and is almost filled by a saccular dilatation of the intestine, which forms a blind sac in front of the sacrum ; there is no anus. A blind coil of intes- tine fills the cavity of the umbilical cord and communicates with the main intestinal cavity at the umbilicus. The whole was filled, according to Mr. Young, with a dark fluid resembling meeonium, although there is apparently no vestige of a liver. In the upper part of the trunk the lungs may be distinctly seen, compressed against the vertebral column. No other internal organs have been developed. The external generative organs are probably those of un imperfect male. The penis is rudimentary, perforated at its D 2 30 ABNORMAL CONDITIONS OF THE AXIS. extremity only, and having a blind urethral pouch immediately beneath its root. There is no bladder. Presented by G. W. Young, Esq. 136. A cyst with a portion of the stomach and jejunum from a lad between 15 and 16 years of age. The cyst contained the imperfect male foetus preserved in the next prepara- tion, No. 136. The case was described in a pamphlet by N. Highmore, Esq., in 1814. The cyst in this case is intimately and extensively connected with the duodenum and jejunum. A portion of the stomach, which is excessively elongated, is seen on the left of the preparation ; it has been filled with horsehair. The duodenum is seen opening on the left into the upper part of the cyst ; from this point the intestine forms part of the wall of the cyst as far as the right extremity of the preparation, where the opening of the jejunum is seen ; a piece of glass tube has been inserted into this opening. The intestine was below and not above the cyst when it was in situ. The interior of the wall of the cyst, except that portion of it which was formed by the intestine, is covered with ragged pro- cesses of membrane, so that it has a villous appearance. The funis arose from the posterior and upper part of the cyst (the lower part in the preparation). The whole was very vascular, and the lad died of haemorrhage into its interior. Presented by N. Highmore, Esq. 137. The foetus from the same. There is no head, but some slips- of membrane unite the upper part of the vertebral column with the funis ; they represent the membranes of the brain. A quantity of long, thick, matted hair is seen growing from near the same point, probably from what should have been the frontal region. The limbs are very ill pro- portioned and are violently flexed. The hands are at right angles to the arms. The whole of the left leg has apparently been absorbed, a large denuded surface on the side of the pelvis being the only indication of its ever having existed. The right foot is bent inward as in ta- lipes varus. The sharp angles of the joints have under- gone absorption, the bones being denuded and partially removed at these points. The upper part of the body has a long fleshy papilla growing from it, enlarged and hol- low at its extremity ; it is undoubtedly a frontal pro- boscis. In Mr. Highmore's original description it has DUPLICITY. 37 been mistaken for a nipple, and hence the foetus was er- roneously described as a female. The generative organs are those of an imperfect male, consisting of a rudimentary penis invested by a very voluminous circular prepuce. The fun is is short and thick, and when recent the foetus was covered with sebaceous secretion. Presented by N. Higkmore, Esq. C. By Adhesion. This is a much less intimate mode of union, and probably takes place at a much later stage of development. It occasionally happens that both foetuses are well developed, especially when they adhere by the skulls, the brains and their membranes remaining separate ; much more frequently one foetus is very defective ; it often forms a mere tumour, especially when adherent to the nates of the other. a. Craniopagus. 138. The skull of a Bengalee child, with a second imperfect skull attached to the anterior fontanelle, which is widely ex- tended. The base of the second skull is much contracted, the foramen magnum being almost closed. All the bones of the face are much smaller than those of the supporting skull. The faces are turned in almost opposite directions, so that the left frontal bones of one skull articulate by suture with the right parietals of the other, and vice versa. The history of this skull and an account of the child are given in the Phil. Trans, vol. Ixxx. p. 296, from which the following particulars are extracted : The child was a male, it was more than four years old at the time of its death, which was caused by the bite of a cobra. It was very emaciated, a fact attributed to the parents having used it as a show, always keeping it covered up, except when payment was made for its exhibition. The woman who acted as midwife was terrified at the appearance of the additional head, and tried to de- stroy the child by throwing it on the fire : it was rescued after one eye and ear were considerably burnt. There was no trunk to the second head ; but it was surmounted by a short neck terminating in a rounded tumour, which is stated by one observer to have been quite soft at the age of two, and by another to have been quite hard and cartilaginous at the age of four. Its external ears were represented by mere folds of skin, and 38 ABNORMAL CONDITIONS OF THE AXIS. there was no auditory meatus. The normal face and head were not malformed. The brains were distinct, each invested in its own membranes ; the dura mater of each adhered to that of the other at the point of contact. The chief supply of blood to the upper head was by a number of vessels passing from the membranes of one brain to that of the other. The movements of the features of the upper head appear to have been purely reflex, and by no means to have been controlled by the feelings or desires of the child. The movements of the eyes of the accessory head did not correspond with those of the child, and the eyelids were usually open, even during sleep. Hunterian. b. Ischiopagus. A second foetus, or more generally an amorphous tumour of connective tissue containing bones, cartilage, and other remains of a second foetus, adheres to the gluteal region. 139. A tumour of somewhat conical form, composed of fibrous tissue, fat, and cartilage, which was removed from the nates of a child about 14 months old. A papilla at its extremity appears to represent very obscure indications of a limb. The remains of a portion of intestine, origi- nally blind at each extremity, and about 3 inches long, is seen at its base. It originally contained a fluid re- sembling meconium. The child recovered quickly from the operation. The tumour has been cut through verti- cally to show its structure. Presented by T. Blizard, Esq. Class III. EXCESS OF GROWTH (GIANTS). [Arranged in the Osteological Series.] Class IV. ARREST OF GROWTH (DWARFS). [Arranged in the Osteological Series.] Class V.- ARREST OF DEVELOPMENT. Subclass I. Cranial arrest. Two principal forms of arrest of development occur in the cranial region. Either the lateral arches fail in their develop- ARREST OF DEVELOPMENT. 39 ment, giving rise to median fissures, or the cranio-facial axis fails and undergoes atrophy or absorption, and the lateral arches unite prematurely, so that fusion of the lateral organs results. In the first case there is usually some shortening of the cranio- facial axis, at least in extreme cases. In the second form the axis becomes narrowed, or is absent in parts of the skull, and the corresponding nervous and facial structures fail to be developed. The presence of lateral parts corresponding to the several por- tions of the axial region affords a strong indication that the axial parts are not absent from the commencement of development, but that they fail to be developed and become atrophied at an early stage. The most common form originates in the absence or failure of the parts developed from the investing mass in front of the notochord, the olfactory lobes and nasal capsules are then deficient. When the investing mass fails more posteriorly the eyes and mesencephalon are found wanting. When the invest- ing mass fails in front of the ear-capsules, so that the basi- occipital ends in a point between them, the mandible is absent ; and in extreme cases, when the structures normally developed in the investing mass in front of the ear-capsules all fail, the tympanic cavities are fused in front. It frequently happens that the mesencephalic or epencephalic region are deficient, whilst the anterior and posterior portions of the cranio-facial axis are developed. The changes which produce these abnormal condi- tions probably commence in the investing mass, and not in the subsequently formed bones, since failure as frequently occurs between the bask>ccipital and basisphenoid as in either of these bones. In this case the anterior part of the basioccipital and the posterior part of the basisphenoid are equally arrested. The nerve-centres appear to be always arrested at points correspond- ing to the deficient portions of the axis, so that it appears im- probable that the malformation originates in deficiency of the facial arches. Rarely one lateral half only of a portion of the cranium is arrested, the other being normally developed. IN FISHES. 140. The anterior portion of an eel with complete deficiency of the face in front of the eyes. The mandible extends be- 40 ABNORMAL CONDITIONS OF THE AXIS. yond the anterior extremity of the truncated skull. The cranium and part of the spinal canal has been laid open. The four anterior ganglia are much compressed from before backwards. The anterior pair (olfactory) have displaced the second pair, the cerebral hemispheres, and lie partially between instead of entirely in front of them. 141. The head of a young Salmon with a similar truncated face; the maxillse are placed almost at right angles to their normal position, and lap over the mandible on either side. Presented by Mr. Shepherd, 1871. 142. A vertical longitudinal section of the anterior part of a Carp, with complete deficiency of the face in front of the eyes. The development of the mandible is likewise defective ; it does not extend beyond the truncated face. Hunterian. IN BIRDS. 143. A Sparrow with a' deep cleft dividing the mandible and lower beak in the mesial line. Hunterian. 144. A fcetal Chick in which the anterior portion of the cranio- facial axis is absent. The eyes are fused into a single organ. The upper beak and the maxillary and frontal arches are entirely wanting. Purchased. IN MAMMALS. A. Facial arrest. Facial arrest in its slightest degree consists in arrested deve- lopment of the intermaxillaries and maxillary bones, so that a cleft is left between them, constituting cleft palate or Hare-lip. The nasal septum is defective in the more severe forms, or the whole anterior part of the axis, including the ethmoid bone, may be deficient. All the facial bones may be very defective, with shortening of the bones of the base of the skull. Very frequently this shortening appears to be accompanied by an increase of breadth in the axial bones, giving rise to considerable clefts be- tween the arrested parts of the face. 145. A portion of the skull of a six-months* foetus with consi- derable deficiency of the maxillae and palate-bones, giving rise to a wide cleft in the palate. The vomer supports ARREST OF DEVELOPMENT. 41 the intermaxillaries, which are separated by a fissure on either side from the maxillae. Presented by Sir W. Fergusson, Bart., 1865. 146. A portion of the skull of a new-born child, with considerable divergence of the pterygoid process and palate-bones. There is entire deficiency of the bony palate, and the maxillae are widely separated from each other and from the premaxillaries. Presented by Sir W. Fergusson, Bart. 147. A portion of an adult skull in which there is a cleft nearly an inch wide between the lateral halves of the bony palate. The vomer is bent over to the left side, and is united to the left half of the palate. The alveoli are very defective. There are only two teeth on the left side. Presented by Sir W. Fergusson, Bart. 148. The intermaxillary bones from eight cases of cleft palate in infants. Presented by Sir W. Fergusson, Bart. 149. The intermaxillary bones from two cases of cleft palate in children. Presented by Sir W. Fergusson, Bart. 150. The intermaxillary bones from a case of cleft palate in an adult. Presented by Sir W. Fergusson, Bart. 151. A dissection of the tensor and levator palati muscles and the neighbouring parts in a case of cleft palate in the adult. The soft palate only -is apparently cleft in this case, but the bones are implicated slightly, although to a much less extent than in the foregoing preparations. The preparation is of special in- terest because it shows the manner in which the levator palati and palato-pharyngei muscles keep the edges of the soft palate apart. The upper fibres of the superior constrictor, which act as their antagonist, are unusually well developed. This is the original dissection on which Sir W. Fergusson founded his operation of Staphylorophy, which consists in dividing the fibres of the levator palati, palato-pharyngei, and palato-glossi. The preparation is minutely described in his original description of the operation, published in 1845, 'Trans. Med.-Chir. Soc.' vol. xviii. p. 273-301. Presented by Sir W. Fergusson, Bart. 152. The head of a young Lion born in the Zoological Gardens, March 1862, with cleft palate and arrested growth of the septum narium. The litter consisted of two, this and another in the same condition. The alveoli of both jaws 42 ABNORMAL CONDITIONS OF THE AXIS. are arrested also. Several other Lion-cubs born in the Gardens have been similarly affected. Purchased. 153. The skull of a new-born Calf with a cleft between the max- illary bones, and defect of the palate-bones and pterygoid processes. The whole skull is shorter and broader than the normal type. There is considerable shortening and deformity of the mandible. Hunterian. 154. The skull of a similar Calf with more considerable shorten- ing of the whole axis, and extreme curvature of the rami of the mandible. Presented by T. Wormald, Esq. 155. A portion of the head of a Human infant, with arrested development of the ethmoid bone, absence of foramina in the cribriform plate, of the nasal septum and premax- illaries. There is a single median nostril and a deep cleft between the lateral halves of the upper lip. In this case the foramen ovale of the heart was patent, the testes had not descended, and there were six digits on each hand and one foot. (See Nos. 308-310.) Presented by R. Partridge, Esq. 156. The head of a female Human foetus, with a broad cleft in the upper lip continuous with the nostrils, arrest of the septum narium, and entire deficiency of the bony palate. There is also apparently considerable deficiency of the skull in the occipital region, similar to that exhibited in No. 279. Hunterian. 157. The head of a Human foetus with arrest of the ethmoid bone and nasal septum. The eyes are approximated. There is no palate. The nostrils are absent, and the upper lip is deeply cleft in the mesial line. A section has been made through the mandible and tongue to exhibit the condition of the roof of the mouth and the nasal cavity. Presented by Sir W. Blizard. 158. A portion of the head of a Human foetus with shortening of the whole cranip-facial axis. The right eye is abnor- mally small, and the left is deficient: its eyelids are wanting, and a mere depression marks the position of the orbit. The palate and the upper lip are entirely wanting. The maxillary and naso-frontal processes remain distinct. The external ears present numerous abnormal lobules. The base of the skull has been dissected to show the ARREST OF DEVELOPMENT. 43 imperfect condition of the middle ear and tympanic bones. The right Eustachian tube is marked by a black bristle ; it is a mere groove open below. 159. A vertical section of the head of a Human foetus in which the palate is entirely deficient. A groove above the mouth, marked by a bristle, represents the nasal cavity. The cribriform plate of the ethmoid is very small, its vertical plate is absent. The palato-pterygoid and max- illary process (suborbital arch) are absent. The eye is abnormally small. The external ear is represented by a small lobule; there is no meatus. The cavity of the skull occupied by the middle cerebral lobe is much enlarged ; the remainder of the cranial cavity is correspondingly contracted. 13. Prosencephalic arrest. Syn. Cyclops, Gurlt. Ehinocephalus, Cyclocephalus, Ethmocephalus, Geoff. W. Vrolik* first ascribed the origin of the following forms to arrest of development of the anterior portion of the investing cartilage of the notochord ; and there can be little doubt that this is the most satisfactory explanation yet arrived at. The trabecular arch and the structures arising from it are always absent or defective. The nasal septum is either entirely absent, or is represented by a defective vomer. The whole ethmoid bone is usually wanting. There are traces of inferior spongy bones in the frontal proboscis, a process arising from {fie union of the naso-frontal processes. There is sometimes a single nostril, sometimes a pair beneath the eyes, between the united sub- ocular arches, when a defective nasal cavity exists between the maxillae. More frequently the proboscis is perforated by a nostril, and contains a cavity extending back to the skull, in which a pair of cartilaginous spongy bones are situated. In such cases the maxillary bones are very massive and are fused in the median line. The orbits are united into a single cavity, and the eyes are more or less perfectly fused, sometimes forming a single globe. The brain exhibits unmistakable signs of arrest. * Over den Aard en Oorsprong der Cyclopie : Amsterd. 1834. Miillor's Arch. 1836. ^4) ABNORMAL CONDITIONS OF THE AXIS. The corpus callosum is almost always absent, the fornix is ab- sent or rudimentary, the cerebral lobes are usually very defec- tive and are fused in front with each other ; the third and lateral ventricles, in most cases, are opened out into a large cyst, which occupies the greater part of the cranial cavity, a condition which may well induce the belief that the cause of the phenomenon is probably internal hydrocephalus at a very early period of em- bryonic life. It is certain that hydrocephalus often accompanies this condition : examples are seen in specimens Nos. 185 and 186. a. Hhinocephalus. Syn. Rhmocephalus and Cyclocephalus, Geoff. Cyclops, Gurlt. In Rhmocephalus the naso-frontal processes form a frontal proboscis. 160. A foetal LamVs head with entire deficiency of the axis in the facial region, a solid frontal proboscis, partially fused eyes, and a pair of imperfect nostrils between the maxillae. The roof of the skull has been removed to show the com- plete absence of the ethmoid bone and fusion of the optic foramina. Hunterian. 161. The brain of the same showing the fusion of the hemi- spheres in front, the absence of the corpus callosum, the open condition of the large third ventricle, and the com- plete absence of the olfactory nerves. Hunterian. 162. The head of a foetal Boar, with complete deficiency of the facial axis. The eyes are partially fused. An orifice cor- responding to the nostrils is situated at the extremity of the proboscis. Hunterian. 163. A similar preparation with the eyes more closely united. Hunterian. 164. The head of a foetal Sow, similar to the last two, but with the eyes still more closely united. Hunterian. 165. The head of a foetal Sow, in which the frontal proboscis is turned back over the forehead. The eyes are fused as far as the edges of the cornese. 166. The head of a foetal Pig with the eyes fused into a single globe. The roof of the skull has been removed to show ARREST OF DEVELOPMENT. 45 the brain. The cerebrum is very small ; its anterior lobes are completely fused. The middle lobe of the cerebellum and the corpora quadrigemina are proportionately very large ; the latter are not covered by the cerebrum. Hunterian. 167. The head of a similar foetal Pig. The roof of the skull has been removed. The cerebral lobes are completely fused in front. The whole brain scarcely fills a quarter of the cranial cavity. Hunterian. 168. A similar preparation, but the eye is apparently very de- fective. The cornea and lens seem to have been arrested in their growth. The cornea is conical. Hunterian. 169. A similar specimen with the side of the face dissected to show the form of the skull, the superior maxillary bone, and pterygoid processes. The zygoma and the ascending ramus of the mandible have been removed. The pro- longation of the frontal bones into the proboscis is well seen in this preparation. Mus. Brit. 170. The head of a foetal Pig with cyclopia, dissected, to show the condition of the brain and nerves. The distribution of the ophthalmic branch of the fifth to the proboscis, and the superior maxillary nerves to the maxillae, is well seen on the right side of the head. The brain is exposed on the left side. The small hemispheres are fused together. The"' corpora quadrigemina and the cerebellum are not covered by the cerebrum. 171. A dissection of the head of an Indian wild Boar with simi- lar deficiencies. The upper preparation consists of a section of the head. The cavity of the proboscis extends back to the cranial bones and con- tains a cartilaginous fold, probably the inferior spongy bones. The lower preparation shows TiHe maxilla and teeth, the pterygoid and styloid process, the middle ear and its ossicles, together with the gustatory and hypoglossal nerves. 172. A foetal Boar with similar deficiencies. There is consi- derable inequality of development on the two sides, with consequent dislocation of the eye. Hunterian. 173. A foetal Hare with similar deficiency. The frontal pro- boscis is comparatively small. Presented by A. Newton, Esq. 46 ABNORMAL CONDITIONS OF THE AXIS. 174. A foetal Kitten with partial fusion of the eyes and a small frontal proboscis. Hunterian. 175. A male Human foetus, about the seventh month of gesta- tion, with deficiency of the facial axis and a frontal pro- boscis. The eyes are contained in a single median orbit and fused as far as the corneas. The right external ear and the thumb of the same side are very defective. Mus. Brit. ] 76. The head of a Human foetus similarly affected. A trans- verse vertical section has been made through the poste- r i r P^ r t of the head to show the condition of the brain. The section passes through the corpora quadrigemina, the fourth ventricle, and the cerebellum. The corpus callosum is absent, the fornix is rudimentary. The cor- pora quadrigemina are very large, the cerebrum is small, and entirely contained in the anterior portion of the skull. The third ventricle, together with the lateral ventricles, forms an enormously dilated cyst, occupying the whole of* the back and upper part of the cranial cavity. Presented by C. H. Welch, Esq., 1868. 177. The posterior part of the brain of the same foetus. Presented by C. H. Welch, Esq., 1868. 178. A longitudinal vertical section of the head of a similar foetus. The cerebral lobes are very small, and exhibit an unmistakable condition of arrest. The corpus callosum is absent, and the fornix is rudimentary. The condition of the ventricles as well as the rest of the brain is similar to that seen in the last preparation. The cavity of the proboscis extends back to the dura mater. b. Arhynchus. Syn. Cyclops Arhynchus, Gurlt. In the following preparations the frontal proboscis is absent, indicating a still higher degree of anterior facial arrest. 179. The head of a foetal Lamb with the eyes partially fused together. The upper part of the skull has been removed to show the small size of the basisphenoid, the persistence of the trabeculae cranii, and the absence of the presphe- noid and ethmoid bones. The optic foramina are fused /e-