ala yg ne a ceery rar See 8 G " 4 brit ye Sindee scar) Pe OR) oT ALBERT R. MANN LIBRARY NEw York STATE COLLEGES OF AGRICULTURE AND HoME ECONOMICS fo ‘a fe \A\ D d gl \& F \eA\ TEER fs} AT CORNELL UNIVERSITY ornell Universit The Arthrostraca of Connecticut, State of Connecticut State Geological and Natural History Survey BULLETIN No. 26 THE ARTHROSTRACA OF CON NECTICUT By B. W. KUNKEL Professor of Biology, Lafayette College HARTFORD PUBLISHED BY THE STATE 1918 BULLETINS OF THE State Geological and Natural History Survey of Connecticut. 1. First Biennial Report of the Commissioners of the State Geological and Natural History Survey, 1903-1904. 2. A Preliminary Report on the Protozoa of the Fresh Waters of Connecticut: by Herbert William Conn. (Out of print. To be obtained only in Vol. 1, including Bulletins 1-5.) 3. A Preliminary Report on the Hymeniales of Connecticut: by Edward Albert White. 4. The Clays and Clay Industries of Connecticut: by Gerald Francis Loughlin. 5. The Ustilaginee, or Smuts, of Connecticut: by George Perkins Clinton. 6. Manual of the Geology of Connecticut: by William North Rice and Herbert Ernest Gregory. (Out of print, except in bound volume. ) 7. Preliminary Geological Map of Connecticut: by Herbert _ Ernest Gregory and Henry Hollister Robinson. 8. Bibliography of Connecticut Geology: by Herbert Ernest Gregory. g. Second Biennial Report of the Commissioners of the State Geological and Natural History Survey, 1905-1906. 10. A Preliminary Report on the Alge of the Fresh Waters of Connecticut: by Herbert William Conn and Lucia Washburn (Hazen) Webster. . 11. The Bryophytes of Connecticut: by Alexander William Evans and George Elwood Nichols. 12. Third Biennial Report of the Commissioners of the State Geological and Natural History Survey, 1907-1908. 13. The Lithology of Connecticut: by Joseph Barrell and _ Gerald Francis Loughlin. 14. Catalogue of the Flowering Plants and Ferns of Con- necticut growing without cultivation: by a Committee of the Con- necticut Botanical Society. 15. Second Report on the Hymeniales of Connecticut: by Edward Albert White. 16. Guide to the Insects of Connecticut: prepared under the direction of Wilton Everett Britton. Part I. General Introduc- tion: by Wilton Everett Britton. Part IJ. The Euplexoptera and Orthoptera of Connecticut: by Benjamin Hovey Walden. 17. Fourth Biennial Report of the Commissioners of the State Geological and Natural History Survey, 1909-1910. 18. Triassic Fishes of Connecticut: by Charles Rochester Eastman. 19. Echinoderms of Connecticut: by Wesley Roscoe Coe. 20. The Birds of Connecticut: by John Hall Sage and Louis Bennett Bishop, assisted by Walter Parks Bliss. 21. Fifth Biennial Report of the Commissioners of the State Geological and Natural History Survey, 1911-1912. 22. Guide to the Insects of Connecticut: prepared under the direction of Wilton Everett Britton. Part II]. The Hymen- optera, or Wasp-like Insects, of Connecticut: by Henry Lorenz Viereck, with the collaboration of Alexander Dyer MacGillivray, Charles Thomas Brues, William Morton Wheeler, and Sievert Allen Rohwer. 23. Central Connecticut in the Geologic Past: by Joseph Barrell. 24. Triassic Life of the Connecticut Valley: by Richard Swann Lull. 25. Sixth Biennial Report of the Commissioners of the State Geological and Natural History Survey, 1913-1914. 26. The Arthrostraca of Connecticut: by Beverly Waugh Kunkel. Bulletins 1, 9, 12, 17, 21, and 25 are merely administrative reports containing no scientific matter. The other bulletins may be classified as follows: Geology: Bulletins 4, 6, 7, 8, 13,18; 23, 24: Botany: Bulletins 3, 5, 10, 11, 14, I5. Zoology: Bulletins 2, 16, 19, 20, 22, 26. These bulletins are sold and otherwise distributed by the State Librarian. Postage, when bulletins are sent by mail, is as { follows: No. 1, $0.01; No. 3, .08; No. 4, .06; No. 5, .03; No. 6, 12; No. 7, .06; No. 8, .05; No. 9, .02; No. 10, .08; No. 11, .07; No. 12, .02; No. 13, .08; No. 14, .16; No. 15, .06; No. 16, .07; No. 17, .02; No. 18, .07; No. 19, .08; No. 20, .14; No. 21, .o2; No. .22, .08; No. 23, .03; No. 24, .10; No. 25, .02; No. 26, .06. The prices when the bulletins are sold are as follows (including post- age): No. 1, $0.05; No. 3, 40; No: 4, .36; No& §, 155 No: 6, 60; No. 7, 60; Ne. $,..201 Noo, 094 No. 10, 95; No. 11, 307 No. 12, .05; No. 13, .40; No. 14, .75; No. 15, .35; No. 16, .35; No. 17, .05; No. 18, .25; No. 19, .45; No. 20, .50; No. 21, .o8; No, 22, $2.00; No. 23, .15; No. 24, .65; No. 25, .05; No. 26, .80. Bulletins 1-5 are bound as Volume I. The price of this Volume is $1.50. Bulletins 6-12 are bound as Volume II. The price is $2.45. Bulletins 13-15 are bound as Volume III. The price is $2.50. Bulletins 16-21 are bound as Volume IV. The price is $2.15. Bulletin 22 is bound as Volume V. The price is $2.50. It is intended to follow a liberal policy in gratuitously dis- tributing these publications to public libraries, colleges, and scientific institutions, and to scientific men, teachers, and others who require particular bulletins for their work, especially to those who are citizens of Connecticut. Applications or inquiries should be addressed to GeEorGE S. GODARD, State Librarian, Hartford, Conn. In addition to the bulletins above named, published by the State survey, attention is called to three publications of the United States Geological Survey prepared in co-operation with the Geological and Natural Survey of Connecticut. These are the following: Bulletin 484. The Granites of Connecticut: by T. Nelson Dale and Herbert E. Gregory. Water-Supply Paper 374. Ground Water in the Hartford, Stamford, Salisbury, Willimantic and Saybrook Areas, Connecticut: by Herbert E. Gregory and Arthur J. Ellis. Water-Supply Paper 397. Ground Water in the Waterbury Area, Connecticut: by Arthur J. Ellis, under the direc- tion of Herbert E. Gregory. These papers may be obtained from the Director of the United States Geological Survey at Washington. CATALOGUE SLIPS. \ Connecticut. ‘Stute geological and natural history survey. Bulletin no. 26. The Arthrostraca of Connecticut. By B. W. Kunkel. Hartford, 1918. 261 pp., 84 fige., 25°. ® Bibliography, }. 258-261. Kunkel, Beverly Waugh, 1881 — The Arthrostraca of Connecticut. By B. W. Kunkel. Hartford, 1918. 261 pp., 84 figs., 25°™. Bibliography, p. 258-261. CATALOGUE SLIPS. Zoology. Kunkel], B. W. The Arthrostraca of Connecticut. Hartford, 1918. 261 pp., 84 figs., 265°. (Bulletin no. 26, Connecticut geological and natural history survey.) Bibliography, p. 258-261. Crustacea. Kunkel, B. W. The Arthrostraca of Connecticut. Hartford, 1918. 261 pp., 84 figs., 25°”. t (Bulletin no. 26, Connecticut geological and natural history survey. ) Bibliography, p. 258-261. tate of Gonnecticut PUBLIC DOCUMENT No. 47 State Geological and Natural History Survey HERBERT E. GREGORY, SUPERINTENDENT BULLETIN No. 26 HARTFORD Printed by the State Geological and Natural History Survey 1918 State Geological and Natural History Survey COMMISSIONERS Marcus H. Hotcoms, Governor of Connecticut ARTHUR TwiINING HapD_ey, President of Yale University WILLIAM ARNOLD SHANKLIN, President of Wesleyan University FLAVEL SWEETEN Lutuer, President of Trinity College CHARLES Lewis BEACH, President of Connecticut Agricultural College FREDERICK HENRY SyYKES, President of Connecticut College for Women SUPERINTENDENT HERBERT E. GREGORY Publication Approved by the Board of Contro THE ARTHROSTRACA OF CONNECTICUT By B. W. KUNKEL Professor of Biology, Lafayette College HARTFORD Printed for the State Geological and Natural History Survey 1918 CONTENTS INTRODUCTION Economic ieiporianes , Classification of the Arthrostraca PART 1. AMPHIPODA Key to the Sub-orders of Aegnaeas Anatomy General Form of Baa andl Telson Appendages Antenne Mouth Parts Gnathopods and Pereiopods Abdominal ci Sense Organs Internal Anatomy Sexual Differences Size Color Habitat Movements Food Enemies Resistance to Aavene Condiibins Molting , Nests and Nest- ahletnn Breeding Habits List of Species Hyperiidea Gammaridea : Key to the genera of Gammarides Caprellidea PART 2. IsopoDA Key to the Sub- eaders of isoaarta External Anatomy Internal Anatomy Biology PAGE 11 13 15 15. 15 15 18 18 20 23) 25 26 27 31 32 32 33 35 37 33 38 39 39 40 43 44 47 47 174 185 185 185 189 189 CONNELTICUT GEOL, AND NAT. HIST. SURVEY. [Bull. PAGE List of Species . 190 Key to the Genera of Taped 191 Tanaioidea or Chelifera 193 Cymothoidea or Flabellifera 197 Idotheoidea or Valvifera 214 Aselloidea or Asellota 230 Bopyroidea or near 235 Oniscoidea . : i F : s 237 LIST OF FIGURES" ‘ , : ; ; 255 BIBLIOGRAPHY . . ; 3 : - 258 INTRODUCTION. The purpose of this report is three-fold; first, to describe and figure as far as possible all the Arthrostraca which have been collected within the limits of the State of Connecticut; second, to describe briefly those forms which have been reported from neighboring States only, but whose habitat probably ex- tends to this region; and third, to furnish to the general student an account of the anatomy and biology of the group as repre- sented by species of this State. The Amphipoda will be treated more fully than the Isopoda because the latter group has already been discussed, in the excellent account of the Rev. T. R. R. Stebbing in his History of Crustacea (D. Appleton & Co., 1893) PP. 314-435; in the briefer paper by Miss Richardson in the Pro- ceedings of the United States National Museum, vol. 27, pp. 1-31, 1905; and in Harger’s valuable paper on the Marine Isopoda of New England in the Report of the United States Commissioner of Fisheries for 1878, pp. 297-462. Among the works that have been consulted and have proven of greatest value in the preparation of this report, may be men- tioned Della Valle’s monograph on the Gammarini (Fauna und Flora des Golfes von Neapel, vol. 20, pp. 1-296, 1893) and Mayer’s work on the Caprellidea (Ibid., vol. 6, pp. 84-184, 1882, and vol. 17, pp. 94-144, 1890.) These volumes contain very full accounts of the anatomy and biology of the groups as a whole. For the description of species, attention should be called to Stebbing’s Gammaridea (Das Tierreich, Lief. 21, pp. 1-806, 1906), which gives descriptions and determinative keys with full synonomy for all the Gammaridea described up to 1898, and to G. O. Sars’s Crustacea of Norway (vol. 1, pp. I-7II, 1890-1894), in which the descriptions are particularly accurate and the figures reliable. Without the help afforded by these figures the labor of preparing the ones for this report would have been vastly increased. The various publications of Holmes on the North American Amphipoda have also been freely re- 9 IO CONNECTICUT GEOL. AND NAT. HIST. SURVEY. (Bull. sorted to as the numerous references will testify. The works of Miss Richardson, especially her monograph on the North Ameri- can Isopoda (Bull. U. S. Nat. Mus., No. 54, 1905), of Oscar Harger, and of G. O. Sars, have been very useful in the study of Isopoda. Besides these, the classic Vineyard Sound report by Verrill, Smith, and Harger (Rep. U. S. Com. Fish. for 1871-2, pp. 295-747, 1874) and a Biological Survey of the Waters of Woods Hole and Vicinity, by Sumner, Osburn, and Cole, (Bull. Bur. of Fish., vol. 31, 1913) have proven mines of information pertaining to the habits.and natural history of the Arthrostraca of Connecticut. The material upon which this report is based consists largely of the collections of Amphipoda and Isopoda made by the United States Fish Commission at Noank, Connecticut, in the summer of 1874, and very kindly loaned by the Smithsonian Institution, and the extensive collections in Peabody Museum of Yale University, made mostly by Professors Verrill and Smith in the neighborhood of New Haven. As might be expected, there are very few species from this State which have not already been reported. Holmes in his paper on the Amphipoda of Southern New England (Bull. U. S. Bur. Fish., vol. 24, pp. 457-529, 1905) and in his key to the Amphipoda of North America published in the American Naturalist, (vol. 37, pp. 267-292) has reported all the Amphipoda which have been found in Connecticut with the exception of Photis reinhardi Kroyer, and one species Tmetony« quadratus which is here described and figured for the first time. Miss Richardson has included in her key to the Isop- oda of North America (Amer. Nat., vol. 34, pp. 207-230 and 295-309) all the species of Isopoda which we have met with in the present study. Notwithstanding the fact that so few additions to the fauna of New England are made in this report, it is hoped that the publication of the figures of native forms, together with a gen- eral account of the anatomy and biology of the Arthrostraca, will stimulate interest in this group and be of service to students. No. 26.] ARTHROSTRACA OF CONNECTICUT. II ECONOMIC IMPORTANCE. Except for a few species which destroy submerged timbers, the economic importance of the Arthrostraca is indefinite but probably great on account of their large numbers and their widely extended habitat. Many species perform an important service as scavengers by destroying decaying matter along the shore. According to Miss Richardson, certain parts of the coast of France, where shark-fishing is carried on extensively, would be almost uninhabitable were it not for the swarms of Isopoda which consume the heads of ‘the sharks which are thrown back on the beach and which would otherwise become highly offensive. Naturalists in the Arctic regions, where the Amphipoda are especially numerous, obtain thoroughly cleaned skeletons of bears and other animals by exposing their bodies alongside of their boats to the shoals of small Amphipoda, which pick them absolutely clean. According to Mr. Geoffrey Smith in the Cambridge Natural History, Amphipoda, “when crowded sufficiently, will even attack living fishes, and by sheer press of numbers impede their escape and devour them alive.” It is hardly possible, however, that any appreciable number of fish are so destroyed. The Amphipod, Chelura terebrans, and the Isopod, Limno- ria lignorum, often occurring together as well as with the “ ship-. worm,” Teredo, do great damage by destroying submerged tim- bers. Chelura is quite abundant on the European coast and has been reported from Bermuda, but on the Atlantic coast of New England it has been reported only from Woods Hole and Prov- incetown, ‘Massachusetts. At the latter place, Professor Verrill found it from:8 to 12 feet below low water. (Smith, Proc. U. 5. Nat. Mus., vol 2, p. 232, 1879.) Along the Connecticut shores Limnoria is the most important crustacean which destroys timbers. Verrill, in the Report on the Invertebrates of Vineyard Sound (p. 379), describes it as eating burrows into solid wood to the depth of about half an inch. These burrows may be so numerous that the outer layers of the timbers decay rapidly and are washed away readily by the waves, leaving a new surface which in turn is attacked by the crustacean. It works chiefly in the softer parts of the wood between the hard annual layers and avoids knots and those 12 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. parts which are impregnated by iron rust from spikes, etc. When abundant it will destroy soft timber at the rate of half an inch a year, thus reducing the diameter of a pile, for example, by one inch in that time. On the average, however, the rate of de- struction is only about half of this. As early as 1875 Andrews observed Limnoria attacking the gutta percha of submarine tele- graph cables. (Quart. Jour. Micro. Sci., ser. 2, vol. 15, p. 332, 1875.) The holes made by this Isopod are nearly round and may be a sixteenth of an inch in diameter. They go into the wood at all angles and are usually more or less crooked. The species is con- fined to a rather narrow zone extending a short distance above and below low-water mark. The burrows are made by means of the stout mandibles and the excavated material is eaten; thus the burrow affords the animal both food and shelter. The remedies against this animal are chiefly copper, or other metallic sheathing, broad-headed iron nails driven close together, and coal tar, creosote, or copper paint applied to those parts which are liable to be attacked. Certain of the terrestrial Isopoda also damage vegetation to some extent by feeding upon the more tender portions of plants. In Louisiana and Texas Armadillidium vulgare, accord- ing to Miss Richardson, is a menace to cucumbers and other plants grown in hot houses as well as to young cotton, and in Virginia it is “one of the most destructive pests with which the mushroom grower has to deal.’ Besides the rdles already mentioned, the Arthrostraca are important as food for certain fishes, forming, with the shrimps, a very large part of the food of most of our more valuable edible fishes. Professor Verrill states that the Amphip- oda occur in such immense numbers that they can nearly always be obtained by the fishes that eat them, and that the voracious blue fish feed upon them even when menhaden and other fishes which they prey upon are plentiful in the same neighborhood. Among the species of Amphipoda taken from the stomachs of porgies, tom cod, and herring caught at Woods Hole and New Haven, large numbers of Unciola irrorata, Ampelisca sp?, Gammarus annulatus, G. locusta, Calliopius leviusculus, and Leptocheirus pinguis have been recorded by Verrill. No. 26.] ARTHROSTRACA OF CONNECTICUT. 13 CLASSIFICATION OF THE ARTHROSTRACA, The Amphipoda and Isopoda together constitute the tribe or legion of the Malacostracous Crustacea known as the Arthros- traca. The Arthrostraca are characterized by the absence of a carapace, the head being fused with never more than one thoracic segment, the presence of only seven free thoracic segments, a single pair of maxillipeds, sessile eyes, and thoracic limbs ‘which are uniramous throughout life. Thé two groups in question are sometimes referred to as the sessile-eyed Crustacea (Edrioph- thalma) to distinguish them from the other Malacostraca in which the eyes are mounted on movable stalks, the stalk-eyed Crustacea (Podophthalma), The Amphipoda may be defined as Arthrostraca in which the body is generally strongly compressed from side to side; and with the abdomen consisting typically of six segments and a telson. The gills are borne on the inner side of the proximal joints of the thoracic legs, and, corresponding to the position of the gills, the heart lies in the anterior part of the body. The Isopoda may be defined as Arthrostraca in which the body is generally strongly flattened dorso-ventrally ; with the abdomen composed of six segments, which may be partly or wholly fused together, and the terminal one which is referred to as the telson and is large and shield-like but rarely free; the respiratory organs are borne on abdominal segments and consequently the heart has an abdominal position. The most important characteristics which distinguish the two groups are: (1) The general form of the body which is flattened in the Isopoda, and compressed laterally in the Amphipoda; and (2) the respiratory organs, which are usually modified pleopods in the Isopoda, and always appendages of the thoracic limbs in the Amphipoda. In the former group the five anterior abdominal appendages are usually broad plates which are all more or less similar in shape and size. In the Amphipoda the first three pairs are similar, being long, narrow appendages adapted for swimming while the last three pairs are short and stiff and are adapted for leaping. ' The classification of the Amphipoda into families is not in an entirely satisfactory condition. The group is very diversified and there is a great difference of opinion regarding its proper 14 CONNECTICUT GEOL. AND NAT. HIST. suRVEY. _ [Bull. subdivision. Della Valle groups all the Gammaridea into only ten families. Sars recognizes twenty-five families in the Nor- wegian fauna alone; Stebbing in the “Challenger” Report divided the Gammaridea into twenty-six families and in his later work on the Gammaridea, 1906, he recognizes forty-one families. I have followed pretty closely Stebbing’s later classification in this paper and have attempted no revision of the group whatever. No. 26.] ARTHROSTRACA OF CONNECTICUT. 15 PART I. AMPHIPODA. KEY TO THE SUBORDERS OF AMPHIPODA. The.Amphipoda are divided into three suborders which may be readily distinguished from each other. A. Eyes large, covering nearly the whole side of the head; uro- pods usually with laminate rami which form a tail fan with THE tOlSOny 4 ¢ sav comconivann a eiycbad Gas magatoieaiie pros HYPERIIDEA p. 44 AA. Eyes usually present but never enormously developed. B. Abdomen well developed.................. GAMMARIDEA p. 47 BB. Abdomen rudimentary; body extremely slender : ‘ CAPRELLIDEA p. 174 ANATOMY GENERAL Form oF Bopy AND TELSON In all the Amphipoda except the Caprellidea, the general aspect of the body is quite uniform, being slender and slightly tapering at each end and usually compressed laterally. In only a few genera, such as Corophium, Siphonecetes, Unciola, and Chelura, is the body cylindrical or depressed. The Lysianas- side and Ampeliscide are the most compressed forms. The Caprellidea are slender and threadlike. The body is divided into three regions: the head or cephalon, the thorax, and the abdomen. The head never exhibits its segmental structure and the number of segments represented in this region is still in question; it is probably seven. The thorax is made up of seven segments, and the abdomen of six, exclusive of the telson, which is probably not of the nature of a regular segment of the body. The abdomen always is made up of three freely articulating segments anteriorly, followed by three which are never very movable and may suffer more or less fusion; thus the fourth and fifth segments are fused in Dexamine and Ampelisca and the fourth, fifth, and sixth are consolidated in Chelura terebrans. This fusion, however, is of no great system- atic value, since in different species of the genus Corophium, for example, the last three segments may be either fused or all distinct. In the Caprellidea the abdomen is very rudimentary and is generally devoid of any indication of segmentation. 16 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. The head is always quite free from the thorax except in the Caprellidea, where it is fused with the first thoracic segment. It is largest in relation to the rest of the body in the Hyperiidea and smallest in the Caprellidea; it is always longer than the first segment of the thorax in the Gammaridea. The anterior margin of the head may be prolonged in front to form a rostrum between the bases of the first antenne. Usually the rostrum is an inconspicuous, pointed process, but in some genera it may form a hoodlike projection over the basal joints of the antenne as in Harpinia, Phoxocephalus, and Para- phoxus. In Siphonecetes the rostrum is spiniform; in Dexamine and Epimeria it is curved ventrally. In the Ampelis- cide the first antenne are so closely appressed that the rostrum is wanting. The anterior margin of the head between the bases of the first and second antenne projects forward as the interantennal lobe, which is usually semicircular but may be acutely pointed or variously modified. In Haustorius, Sympleustes, and Dex- amine, the interantennal lobes are acute. The Ampeliscide are peculiar in the great distance that separates the first and second pairs of antenne and the almost complete disappearance of an excavation in which the latter articulate. Usually the second antenne are joined to the head only slightly posterior to the first pair; but in those forms in which the second antenne are more or less pediform, the front margin of the head may be deeply excavated as in Ischyrocerus, Jassa, Ericthonius, Coro- phium, and Unciola, Eyes are usually present and compound. In a few species they may be lacking, as in Harpinia plimmosa and Stegocephalus inflatus, or imperfectly developed, as in Phoxocephalus holbélli and Haustorius arenarius. In most of the C&diceride the eyes are situated so far dorsally that they are almost in contact with each other. The Hyperiidea have very large eyes that cover the whole side of the head, but in the Gammaridea the eyes are never very enormously developed. It is only in the Ampeliscide that we find the one pair of compound eyes generally present in the Amphipoda replaced by two pairs of eyes provided with simple corneal lenses. No. 26.] ARTHROSTRACA OF CONNECTICUT. 17 The segments of the thorax increase gradually in length from the anterior end to the posterior, except in Harpinia, where the last segment of the thorax is shorter than the preceding on account of the reduction of the last pair of thoracic legs. Although typically the dorsal region of the thoracic segments is smooth and evenly rounded, in a few cases it may be produced to form a keel as in Epimeria and Paramphithoe. The first three segments of the abdomen are always in the Gammaridea deeper than those of the thorax and have the lateral margins prolonged downwards to form pleura; the last three segments are small and do*not have pleura. The dorsal region of the abdominal segments, like the thoracic, is usually evenly rounded, but more frequently than in the thoracic seg- ments, it may exhibit a keel or crest as in Apherusa gracilis, In Ampelisca spinipes and Byblis serrata the fourth segment bears a prominent keel which ends abruptly posteriorly. The first four segments of Calliopius leviusculus are quite characteristically raised posteriorly to form rounded keels, while in Dexamine thea, these segments are prolonged posteriorly to form sharp, spiniform projections, and in Carinogammarus the first three segments only are similarly produced. Many of the Lysianasside and Ampelis- cide exhibit a depression on the dorsal side of the fourth abdom- inal segment which is more pronounced in the male than in the female. In Chelura terebrans, the third abdominal segment bears a long curved process which extends posteriorly. The posterior margins of the three posterior segments may be armed with fascicles of spines, as in Carinogammarus and Gammarus, or produced to form small spiniform projections, as in Mera and Melita dentata, or the spines may be confined to the fourth and fifth segments, as in Leptocheirus pinguis. The postero-lateral angles of the first three abdominal seg- ments are usually evenly rounded but the third is especially modified frequently. Thus in Ampelisca macrocephala, Unciola irrorata, Sympleustes glaber, and Harpinia plumosa, it bears an acute, slightly upturned projection, above which is a rounded sinus, which in some cases may be followed by a rounded lobe. In a few species the postero-lateral margins of the third abdom- inal segment may be serrated, as in Batea secunda; or the second and third may both be so adorned, as in Apherusa gracilis. 2 18 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. The telson has been regarded by some as representing the last segment of the abdomen, but Della Valle and others regard it as simply a development of the posterior end of the rectum, 1n the nature of an anal valve, morphologically equivalent to the upper lip which will be described below. The telson may have the form of simply a thin oval projection as in Lysianopsts and Calliopius. In Amphithoe, Grubia, Sympleustes, and Unciola it is also a simple plate but somewhat thicker than in the pre- ceding genera. In Microdeutopus the rectum passes directly through the telson, which is undivided. The telson may be more or less deeply divided into two lobes as seen best in the Gam- maridz where the lobes are usually rather widely separated from each other and armed apically with a fascicle of spines. APPENDAGES, Each segment of the crustacean body normally bears a single pair of appendages upon the ventral side so that in those forms in which two or more segments are fused together the number of appendages affords a criterion of the fundamental segmentation. In the head region of the Amphipoda, however, the difficulty of determining the number of true segments lies in the fact that an uncertainty exists regarding the homologies of some of the appendages. According to most students of the group, the head is made up of seven segments which bear the following appendages from in front backwards: eyes, first or superior antennz, second or inferior antenne, mandibles,. first and second maxilla, and maxillipeds. The last are regarded as homologues of the first maxillipeds of the Decapoda, and as such are fundamentally appendages of the thorax and not of the head. The mouth parts form the buccal mass projecting from the ventral side of the anterior end of the head. The buccal mass is especially prominent in the Orchestiidea (Fig. 1). In the Caprellidea the first gnathopod, owing to the fusion of the first segment of the thorax with the head, appears to articulate with the head and to be associated with the mouth parts. Antenne. The antenne may be very long, as in the males of many Cediceride, Phoxide, and Lysianasside in which they surpass No. 26.] ARTHROSTRACA OF CONNECTICUT. 19 Fic. 1. Orchestia agilis. the body in length; or they may be short as in Orchomenella. The first antennze only may be extremely short, as in Orchestia and the females of the Hyperiidea. The second antenne are usually more constant in their size but they too suffer considerable reduction in female Hyperiidea and may be very large as in Corophium and Siphonecetes. The first antenne are made up of a peduncle of three segments, followed by a flagellum usually multiarticulate, and sometimes also by a secondary or accessory flagellum. The first joint of the peduncle is characteristically very stout in the Lysianasside. The flagellum may be very short as in Orchestia. The accessory flagellum is lacking in the Ampeliscide, Orchestiide, Stenothoe, Sympleustes, Calliopius, Pontogeneia, Dexamine, Batea, Amphi- thoe, Ericthonius, Corophium, Siphonecetes, and Podoceropsis. In some few genera like Grubia and Jassa, it is quite rudimen- tary and may easily be overlooked. Particular attention is 20 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. called to Calliopius leviusculus, in which the process on the distal end of the last segment of the peduncle of the first antenne may be erroneously regarded as an accessory flagellum. In the Caprellidea the number of segments in the flagellum increases regularly with age, and a secondary flagellum is never present. The second antennz consist of a peduncle of five joints and a flagellum which is usually multiarticulate. An accessory flagellum is never present. Of the peduncular joints only the last two are well developed, the first two are always very short and the first is fused with the head. In the Orchestiide the second joint is likewise fused with the head (Fig. 1). The second joint is characterized by the fact that the antennal gland, probably excretory in function, opens by means of a hollow conical process on its lower side. This gland cone is conspicuous in Melita and is very minute in Orchestia. In some species the second antenne exhibit marked sexual differences. In Coro- phium the peduncle of the male is much stouter and armed with spiniform processes; in the Lysianasside the whole antenna is much longer than in the female, and in Ampelisca the male has a row of tufts of specialized sensitive hairs on the dorsal margin of the peduncle of the second antenne as well as on the ventral margin of the first. The flagellum may be reduced to a rudiment made up of only two or three segments, as in Corophium and Siphonecetes, or may be very long and slender, as in the males of the Cediceride and Lysianasside, and Phoxus. In the Caprellidea of the New England coast, the flagellum is never more than biarticulate. Both antenne may be provided with very curious, slipper- or wineglass-shaped appendages known as calceoli, which probably are sensory in nature. These are disposed along one margin of the peduncles or at the distal ends of the flagellar segments. They are seen in Calliopius, Pontogeneia, and the males of the Ampeliscide. Mouth Parts. The mouth parts lie partly concealed by the projecting coxal plates of the first gnathopods. As viewed from the side, however, the mandibular palps and the maxillipeds extend forward beyond the general outline of the mass. The mandibular palp is directed No. 26.] ARTHROSTRACA OF CONNECTICUT. 21 forward and usually upward between the bases of the antenne, while that of the maxillipeds extends downward and forward, with the terminal joint bent somewhat toward the middle line. The mouth is bounded above by the upper lip, which is a broad plate, circular or oval in outline and continuous by its front margin with the epistome. The epistome forms the ante- rior, ventral surface of the head. The upper lip may form a kind of rostrum projecting forward as in Ericthonius or it may be small and vertical in position as in the Lysianasside. The mandibles bound the mouth laterally and form the prin- cipal chewing organs, being admirably adapted for tearing and cutting by their strength and heavy calcification. In general the mandibles are triangular in shape with the anterior margins inclined toward the middle line, and, except in the Lysianassidz, bear several strong tooth-like processes. Behind this principal incisive plate, or cutting edge, there is often a secondary one movably articulating with it, which is weaker in structure, but likewise usually denticulated. Posterior to the cutting edges, the mandibles generally bear a molar tubercle having the form of a cylinder or truncated cone, which is directed internally and backward, and is armed distally with rasp-like teeth. The tubercle is absent in the Lysianasside. ‘There may also be present a palp, consisting of never more than three joints, which is inserted towards the middle of the anterior surface. In the Orchestiide, Dexamine, Stenothoe, and Caprella, the palp is lacking; in Siphonecetes it is uniarticulate; and in Corophium it is made up of two joints. In species having a triarticulate palp the first joint is always short, except in the Hyperiidea, where it may be somewhat elongated, but is never as long as the last two joints. The terminal joint may be somewhat spatulate as in Ericthonius but more generally it tapers to a slender point as in Gammarus locusta and Elasmopus. The lower lip is inserted immediately beneath the mouth, and is made up of two halves which are united on the middle line for a greater or less distance from the posterior end. Each: plate has a regular anterior margin of semicircular form except in the genera Amphithoe and Grubia, in which there is a deep, rounded sinus, making the plate bilobed. The postero-lateral angles are always more or less prolonged to form the maxillary 22 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. processes. Posterior to the principal lamina there is a smaller accessory one of oval form with its anterior margin entire. The upper and lower lips are regarded as derived from folds of the extreme anterior end of the esophagus and not as true appendages. Hence they are not referred to definite segments of the head. The maxille differ from the mandibles in their laminar form. The first maxillz are more robust than the second and are pro- vided with spines for tearing the food. The first pair are made up of an inner and an outer plate and a palp. The palp never has more than two joints, of which the first is shorter than the second. The inner plate may be almost obsolete as in Coro- phium and Siphonacetes, or large and oval and furnished dis- tally and medially with plumose spines, as in the Gammaride. .. In the Orchestiidz, the inner plate is long and slender and armed distally with two plumose spines. The inner plate is lacking completely in the Caprellidea and Hyperiidea. The outer plate is always larger than the inner. Its distal margin is armed with a row of short spines of characteristic antler-like or comb- like form which are masticatory in function. The palp articu- lates with the outer plate and its apex usually projects beyond the end of the outer plate. The palp is lacking in Orchestia and is rudimentary in Hyale. In Dexaimine and Phoxocephalus it is of a single joint. The free distal margin is sometimes furnished with setules, but more often it bears stout spines or is serrated. The second maxille are always small and flexible. They are made up of an outer and an inner plate which bear setz on the inner and distal margins. The maxillipeds belong morphologically to the thorax, but are discussed here, as is usual, in connection with the appendages of the head. The maxillipeds cousist of an inner plate, outer plate, and palp. The appendages of the two sides are fused together on the middle line by the proximal joint. The inner plates are formed by an anterior and median expansion of the second joint, and the outer plates by a similar expansion of the third joint; the palp is made up of the remaining joints which may be as many as four. In the Hyperiidea the second see- ments are fused together completely on the middle line and palps are wanting; in the Caprellidea the fusion of the inner plates is No. 26.] ARTHROSTRACA OF CONNECTICUT. 23 partial; but in all other Amphipoda the plates are separate and palps are present. The plates are most highly developed in the Lysianasside. They are obsolete in Stenothoe. The inner plates usually bear numerous setz on their inner margins and may bear tooth-like spines apically which are of use in mastication. The outer plate is usually furnished with strong spines and sete on the inner and distal margins. In Amphithoe and Grubia the sickle-shaped spines on the inner margin gradually increase in length toward the apex and become simple slender sete. The first joint of the palp is always short; the second joint is usually cylindrical, but in Orchestia it bears a distal laminar prolongation resembling the inner and outer plates; the third joint is club- shaped or ovoid; and the fourth joint is somewhat conical and may be armed with a stout spine distally. In the genera Haustorius, Orchestia, and Talorchestia the palp is triarticulate, but in all other genera, when present, it is four-jointed. Gnathopods and Pereiopods. In all the Amphipoda there are seven pairs of thoracic append- ages, except in the Caprellidea, in the New England species of which all traces of limbs of the third and fourth thoracic seg- ments are wanting. The first two pairs differ greatly from the others and are generally referred to as gnathopods; so that the third thoracic limb becomeg the first pereiopod. Each thoracic appendage is made up of seven joints which, reckoning from the proximal one, are designated usually as the coxal plate or coxa, basal joint, or basus, ischium, merus, carpus, propodus, and dactyl. In Haustorius the dactyls are wanting in the case of the pereiopods, although present in the gnathopods. Batea is unique in that the first gnathopod is reduced to a mere rudiment repre- senting the coxal plate and basal joint. The first two pairs of pereiopods, like the gnathopods, are usually held flexed forward quite strongly at the joint between the ischium and merus, and the dactyls are directed backwards. They are usually of similar form and size and have slender basal joints. The third, fourth, and fifth pereiopods are more or less flexed backward at the joint between the ischium and merus and the dactyls are directed forwards. The basal joints of the last three legs are typically expanded to form flat plates. 24 CONNECTICUT GEOL. AND NAT, HIST. SURVEY. [Bull. The joints are all movable in a fore and aft direction, except the first or coxal plate, which is attached to the thorax in such a way as to be capable of a slight lateral movement only, and frorn the median side of which the succeeding joint of the pereiopod arises. The ischium is always short, scarcely longer than broad except in the second gnathopods of the Lysianasside. ‘The succeeding joints vary greatly in different species in both their ‘ shape and size; the terminal one, however, is usually claw-like. The coxal plates vary greatly in depth and length both among themselves and in different species. They are very deep, for example in Stenothoe, Metopa, Stegocephalus, and the Lysianas- side, while in the Corophiide they are small and low, not forming a continuous series of overlapping plates as is more common. There is a gradual increase in size from the first to the fourth, which is generally the largest. The fourth may be excavated at the upper posterior angle to accommodate the coxal plate of the fifth pereiopod, but in the following families it is not excavated: Stenothoide, Aoride, Photide, Amphithoide, Jasside, and Corophiide. The fifth, sixth, and seventh coxal plates are often considerably smaller than the preceding, diminishing posteriorly, and are bilobed. Among the Caprellidea the coxal plates are often absent and when present are extremely minute. The gnathopods exhibit great differences in individual species as well as in the two sexes and at different ages. The first pair is smaller than the second except in the genera, Ampelisca, Microdeutopus, Lembos, Unciola, and Leptocheirus, where the condition is reversed. The propodus is usually subchelate; that is, the posterior and distal margins form a palm against which the dactyl strikes when flexed, so that the appendage is adapted for grasping. The angle made by the posterior margin and the palm is known as the prehensile angle and may be armed with one or more stout spines. The dactyl may have its concave margin modified by serrations or processes. In a few species the dactyl does not close against the propodus, in which event the gnathopod is known as simple. This is more frequently the case with the first pair than with the second. Thus in Lysianop- sis alba, Leptocherius pinguis, and the females of Talorchestia, the first gnathopod is simple, and in Ampelisca Spinipes, the second is simple. Besides the simple and subchelate forms of No. 26.] ARTHROSTRACA OF CONNECTICUT. 25 these appendages, there may also be the chelate type, in which the propodus is prolonged at the posterior margin distally so that the dactyl strikes against the anterior margin of this, as in the pincers of the lobster or crayfish. The second gnathopod is chelate in Lystanassa and in the females of Talorchestia and Orchestia. In a few species the gnathopods are found to be complexly subchelate, in that a process of the carpus becomes involved in grasping. Thus in Microdeutopus, the first gnathopod of the male, and in Ericthonius and Cerapus, the second pair is complexly subchelate. Among the Caprellidea the second gnathopods are, as a rule, inserted near the front margin, or at least in front of the middle of their segment, although in the male Caprella the insertion is very near the middle. In a number of families the first and second pereiopods possess peculiar glands situated for the most part in the basal joints, but often extending into the distal joints as well, and opening to the exterior at the apex of the dactyl, which is then slightly truncate, or at a point just proximal to the tip. Such forms as Ampelisca, Microdeutopus, the Amphithoide, Jassidee, and Corophiide, secrete by means of these glands a sticky sub- stance which hardens quickly to form a thread. By means of this secretion a tube is formed for concealment as will be described below (p. 39). In the native Caprellidea the first and second pereiopods are entirely wanting, but the three posterior pairs are well developed and subchelate. They increase in size from the anterior pair to the posterior. Abdominal Appendages. The abdomen bears two quite distinct types of appendages, and for this reason is frequently differentiated into an anterior pleon of three segments and a posterior urosome. Each segment of the pleon bears a pair of pleopods adapted for swimming, each of which consists of an unjointed basal joint or peduncle with two flexible, multiarticulate rami distally. These are pro- vided marginally with long plumose sete. The two peduncles are held together by a series of hooks, called coupling spines, which are situated near the distal end. In Corophium the pedun- cle is broadly expanded medially but in other forms it is more nearly cylindrical in form. 26 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. There are usually three pairs of uropods present. These appendages are never very movable and are always directed posteriorly, and are closely approximated. Like the pleopods they are made up of an unjointed peduncle and two rami, although in the Orchestiidz, and in the genera Unciola, Stenothoe, Siphon- acetes, Corophium, and Ericthonius; the terminal pair is uniram- ous. The rami are usually uniarticulate although the outer one may exhibit also a small terminal joint. The terminal uropods often differ greatly from the preceding pairs in size and form. In Ampelisca and the Gammaride they project considerably beyond the others. In Melita the inner ramus is reduced to a mere scale-like rudiment while the outer one is biarticulate. Usually both the peduncle and the rami bear strong spines along the upper margin and at the tip. In Leptocheirus, Microdeutopus, and Grubia, the peduncle is prolonged beneath the attachment of the rami to form a long, slightly upturned, spiniform process. In Unciola the peduncle is produced into a lobe as long as the single ramus. The rami may be lanceolate or flattened, as is seen best in the Gammaride, or they may be cylindrical or conical with re- curved spines at the apex, as in Jassa, Ischyrocerus, Grubia, and Amphithoe. In Chelura the uropods are highly specialized. The first pair are of the typical form, but the second pair lie well on the dorsal side of the abdomen; the peduncle bears a very large plate-like expansion medially and the rami are scarcely longer than wide; the terminal uropods are very large, with the outer ramus ex- tremely long, especially in the male, and the inner ramus minute. Owing to the extremely rudimentary condition of the abdomen in the Caprellidea, the appendages are greatly reduced. In 4 ginella the first pair of appendages are biarticulate and the sec- ond pair are uniarticulate. In Caprella the males have a biarticu- late pair in front and a thick uniarticulate pair behind. In the females the limb-like (first) pair are reduced to simple eminences bearing a, few setz. SENSE ORGANS. Besides the eyes, which have already been discussed, the sense organs of the Amphipoda consist of various filiform and special- No. 26.] ARTHROSTRACA OF CONNECTICUT. 27 ized processes of the integument, whose exact functions are still largely conjectural. When a foreign chemical substance is placed in a vessel containing Amphipoda, the antenne are waved vigor- ously, which may point towards the conclusion that on these appendages are smelling or tasting organs. The delicate thread- like setee noted frequently on the principal flagellum of the first pair of antenne are called olfactory hairs. The calceoli, which occur in forms like Calliopius, are conical vesicles attached by their apices to the general surface of the skin. They have been called by Leydig “ slipper-shaped” structures, but with greater propriety they might be compared to wine glasses. Their func- tion is wholly unknown. INTERNAL ANATOMY. The nervous system consists of two symmetrical ganglionic chains, united at intervals by commissures, and lying on the Posterior aaa 1 | Aepalopancreas. : een inesting Testis if Carr Slomach anterior aoria Lain a & t < ¢ Fic, 2. Internal Anatomy, after Stebbing. " \ ventral side of the alimentary canal, except at the extreme ante- rior end, where the ganglia are on the dorsal side (Fig. 2). The supraesophageal mass is made up of two halves, separated by a deep median groove, and consists of two large cerebral lobes, as well as a pair of ganglia, which give rise to the optic nérves, and another pair giving rise to the antennal nerves. Beneath the esophagus and connected with the brain by commissures around it, lies the subesophageal mass, which gives off nerves to the mouth parts, and represents the consolidated ganglia of the segments to which the mouth parts belong. The sub- esophageal ganglia are continuous posteriorly with the sub- intestinal ganglionic chain. This consists of a pair of ganglia, 28 CONNECTICUT GEOL, AND NAT. HIST, SURVEY. [Bull. fused together in the middle line, for each body segment except the last three, in which the ganglia are fused to a single mass. In the Caprellidea the ganglia of all the abdominal segments are fused together. : The alimentary canal consists of a straight tube of uniform diameter, except in the anterior portion, where it is dilated to form the stomach. The latter opens anteriorly by a narrow esophagus, which is curved ventrally. The mouth is bounded above and below by the upper and lower lips. The stomach is ovoidal in form and of very complicated structure. As in all the Malacostraca, a gastric mill is present which includes both a grinding and a straining mechanism. The midgut extends from the posterior end of the stomach to the last thoracic segment. Extending forward on the dorsal side of the stomach from the anterior end of the intestine is a so-called pyloric caecum which is single in the Gammaridea but double in the other groups of Amphipoda. Arising likewise from just behind the stomach are the hepato-pancreatic caca which extend to a considerable distance posteriorly, lateral and ventral to the intestine. Typically there are four of these tubes present, but in Corophium and Siphonacetes a single pair is present. In addition to these ceca there is also a “rectal gland,” of cecal form, extending forward and dorsally from the anterior end of the hind gut. This rectal gland probably corresponds to the Malpighian tubules of insects and functions as an excretory organ, accord- ing to W. B. Spencer (Quar. Jour. Micro. Sci., ser. 2, vol. 25, pp. 183-191, 1885). It is confined in most Gammaridea to the last three abdominal segments. The intestine opens to the ex- terior through the anus which lies just below the telson except in the Photide, in which the telson is hollow and is traversed by the posterior end of the hind gut. The circulatory system consists of a heart, arteries, and lacune or sinuses. The heart is tubular in form, open at both ends, and situated in the dorsal part of the thorax immediateiy beneath the integument, and extending as far back as the sixth thoracic segment. On the lateral sides of the organ are three pairs of openings, called ostia, which are oblique slits, guarded by valves which open inward. In the Hyperiidea there are two pairs of ostia usually and in Corophium the number is reduced No, 26.] ARTHROSTRACA OF CONNECTICUT. 29 to a single pair corresponding in position to the last one of other forms. The arteries are reduced to an anterior and a posterior aorta, the openings into which from the heart are guarded by valves opening outward. The posterior aorta hes close against the intestine; the anterior one breaks up principally about the nervous matter of the head. The principal lacune are the pericardium and the ventral lacuna; they have no walls of their own but are simply the spaces between other organs through which the blood courses somewhat irregularly. Internally the Amphipoda and Isopoda differ most strikingly as regards the circulatory system. In the latter group the heart lies principally in the abdomen and ends blindly behind. Besides the anterior aorta, like that of the Amphipoda, there are five pairs of arteries extending forwards. On the ventral side of the body is a large blood sinus which is paired in‘the thorax but single in the abdomen. Five pairs of veins convey blood from the pleopods, which are respiratory in function in the Isopoda, to the pericardial lacuna. In the Isopoda the arterial system is much more complete than in the Amphipoda, where the lacune are relatively more extensive. There is accordingly a more per- fect separation of arterial and venous blood in the Isopoda. The rapidity of the pulsations of the heart is considerable. Ir. young specimens of Microdeutopus Della Valle found the rate to be two hundred per minute. Closely associated with the difference in the position of the heart in the Amphipoda and Isopoda is that of the respiratcry organs. In the former group the gills have the form of flattened oval sacs, depending from the upper posterior corner of the coxal plates, internal to the principal axis of,the limbs. (Figs. 3 and 26.) The gills are confined to the last six thoracic append- ages. Ina few genera the last pair of pereiopods also lack gills. In Ampelisca and Corophium the second gnathopods, of the females only, are devoid of these appendages and in Ericthonius and Cerapus this gill is absent in both sexes. The gills are ex- ceedingly large in Gammarus, but in Orchestia they are very much reduced, in accordance with the semiterrestrial habit of the genus, and are twisted on their long axes instead of being flat plates parallel to the coxal plates. The anterior gills are usually larger than the posterior ones. 30 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. Fic. 3. Cross section through a female Amphipod. The testes are small, slender, fusiform, paired organs which lie directly below the heart and dorsal to the intestine. These organs taper posteriorly to two delicate tubes, the ejaculatory ducts, or vasa deferentia, which open by papillae on the ventral side of the last thoracic segment. In the breeding season these papilla enlarge considerably to form copulatory organs (Fig. 31). The glandular portion of the testes usually lies behind the second and in front of the fifth segment of the thorax. Its anterior end is very attenuated and serves as a kind of ligament to hold the organ in place. In the female the ovaries have the same position as the testes in the male but are somewhat longer. In form the ovary is irregularly cylindrical and when ripe may be more or less inflated. The oviduct opens from the lower outer surface of the ovary at a point corresponding to the fifth thoracic segment and continues as a simple straight tube to the exterior at the base of the fifth coxal plate. Usually there are four pairs of marsupial plates or odstegites borne on the second, third, fourth, and fifth thoracic legs, but in some species there are six pairs attached to the last six legs, and in the Caprellidea there are only two pairs, belonging to the No. 26.] ARTHROSTRACA OF CONNECTICUT. 31 third and fourth segments. They are inserted on the inner surface of the coxal plates except in the Caprellidea and Phronimidz where the attachment is directly to the ventral wall of the thorax. The insertion is nearer the middle line than the gills, so that when the brood pouch is filled with eggs the gills remain free to oscillate and receive fresh water. In form these plates are rather long, tongue-shaped plates the margins of which are always provided with numerous long, slen- der prolongations like exceedingly flexible sete. These prolonga- tions intertwine with each other so that the lamelle form a kind of basket which receives the eggs from the oviducts. SEXUAL DIFFERENCES. The sexes of the Amphipoda are always separate. Usually they are readily distinguished by the large marsupial plates, or odstegites, of the females which support and protect the eggs and immature young. Besides this difference in the two sexes, the males are usually larger than the females and are provided with more sensory spines and sete. It is in the form of the second antenne and gnathopods, however, that the secondary sexual characters are most conspicuous. In striking contrast to the general rule that the second antennz of the males bear more ~ setee than those of the females is the case of Corophium, in which the second antenne of the male have none on the peduncle while those of the female have many. On the first antenne of Am- pelisca and the Lysianasside, calceoli are present in the males but not in the females. The first gnathopods of Orchestia, Cerapus, and Microdeuto- pus are of vastly different form in the male and female, as may be seen by reference to the descriptions of the forms in question. In other genera, like Amphithoe, Hyale, and Gammarus, for example, the sexual differences in the first gnathopods are in- significant. The second gnathopods are strikingly different in the two sexes in Talorchestia, Orchestia, Metopa, Elasmopus, Amphithoe longimana, Jassa, Ischyrocerus, and Ericthontus. In Chelura terebrans, the second and third uropods are quite distinct in form in the two sexes; the second pair is provided with long setz in the male which are lacking in the female; the 32 CONNECTICUT GEOL, AND NAT. HIST. suRvEY. [Bull third pair has a foliaceous outer ramus in the female, and a much larger styliform one in the male. In this species, there 1s great difference between the male and the female in the length of a long styliform process extending backwards from the mid-dor- sal line of the third abdominal segment. The secondary sexual characters are not acquired completely until maturity is reached. The female form may be looked upon as the more primitive, for the young, when first escaped from the egg, generally resemble the female rather than the male. In examining a large number of specimens of Orchestia agilis from Woods Hole it was found that all individuals up to about 7 mm, in length have gnathopods like the female, and in two or three individuals about 7.5 mm. long the first gnathopods were of the male form, and the second pair, of the female. The gnathopods were of exactly the same form as those of the respective adult forms and showed no sign of transition between the two. Although it has been known that the male characters are acquired gradually, there have been no accounts of the condition in which one pair of appendages is male and another female. SIZE: The Amphipoda of Connecticut are in general of small size. The largest species of the coast is probably Gammarus locusta a few specimens of which, collected at New Haven, had a length of 30 mm. As in many other groups of animals a larger size is attained in the Arctic regions or in the cold waters of great depths, Thus Sars records a length of 48 mm. for Gammarus locusta in the Arctic regions, and Professor S. I. Smith (Ann, and Mag. Nat. Hist., ser. 5, vol. 14, page 181, 1884) records an Amphipod, Eurysthenes gryllus Boeck, dredged by the “Alba- tross” in 1917 fathoms which had a length of 4% inches. This probably represents the largest known member of the group. At the other extreme of size are Stenothoe, 2 mm., Dexamine thea 3 mm., and Corophium cylindricum, 3-4 mm. in length. COLOR. The colors of the Amphipoda are frequently quite brilliant in life, but with scarcely an exception specimens bleach to such an No. 26.] ARTHROSTRACA OF CONNECTICUT. 20 extent in preservatives that at best only a.few spots of pigment of a chocolate brown or black ‘remain. The usual color is whitish or grayish but a few of the native species exhibit very characteristic pigmentation. Leptocheirus pinguis, for example, retains its dark chocolate spots even after years in alcohol. Unciola irrorata is mottled with bright crimson, Jassa marmorata is of a reddish ground color, interrupted by large lighter spots. Many species also exhibit great variations in coloring. Amphithoe longimana may vary from bright green to bluish green, or nearly colorless, and also from light to dark reddish brown. According to Holmes (Biol. Bull., vol. 2, p. 181, 1902) the color of some individuals is by no means constant. In Amphithoe longtmana, the species studied by Holmes, the color is due especially to the pigment cells although the color of the blood and tissues, the contents of the alimentary canal, and the color of the reproductive glands also affect that of the body, as scen by the naked eye. In one specimen the general blue color of the blood and tissues after five days had disappeared, the green be- coming more nearly like the typical green of other forms, and by the ninth day the tissues were whitish. This whitening took place in spite of the fact that abundant quantities of green alge were consumed. The most important factors in determining the color changes in Amphithoe longimana are the reddish-brown pigment spots which are scattered all over the body and on most of the append- ages, especially near the proximal end. These pigment spvis change very slowly, generally requiring several hours to effect a change from the expanded to the contracted condition. HABITAT. The Amphipoda are exclusively aquatic in their habitat, and very generally they are marine. It is only among the Orchestiide that there is an approach to a terrestrial habitat. Talorchesta longicornis occupies a zone of the beach a short distance above high-water mark but sinks its burrows to a depth at which the sand is always moist. Orchestia palustris and O. agilis also live near high-water mark, the latter occupying a lower zone than the 3 34 CONNECTICUT GEOL. AND NAT. HIST. suRVEY. [Bull former. Orchestia pulustris prefers mud, and as it is able to survive exposure to brackish or nearly fresh water, it is often found in salt marshes and may find its way to some distance from the shore. Della Valle mentions O. gammarellus, in which species he includes O. palustris, as occurring several kilometers from the sea shore at Naples. Allorchestes littoralis also occurs high upon the beach, according to Holmes. With these few exceptions, however, the Amphipoda are thoroughly aquatic. In New England there are only three species which occur in fresh water: Crangonyx tenuis, which was found by Smith in wells at Middletown, Dikerogammarus fasciatus, and Hyalclla knickerbockert. Dredging operations have been so incomplete in the waters of Long Island Sound within the bounds of the State that it is impossible to generalize from these data alone. The extensive observations made in the nearby waters of Vineyard Sound and Buzzards Bay by Verrill and Smith and also by Sumner, Osburn, and Cole may, it would seem, be extended in the most general way to the shores and waters of Long Island Sound. The following species are known to occur at the surface and to be taken in towing: Allorchestes littoralis Elasmopus levis Ampelisca macrocephala Gammarus aunulatus Amphithoe longimana G. locusta A. yubricata Grubia compta Batea secunda Hyperia galba Byblis serrata Leptocheirus pinguis Calliopius leviusculus Microdeutopus gryllotalpa Carinogammarus mucronetus Paraphoxus spinosus Corophinm cylindricum Pontogeneia inermis Dexamine thea The following species are found most commonly in eel-grass and mud: Amphithoe longimana Grubia compta A. rubricata Leptocheirus pinguis Caprella geometrica Lysianopsis alba Carinogammarus mucronatus Microdeutopus gryllotalpa Elasmopus levis No. 26.] ARTHROSTRACA OF CONNECTICUT. 35 The following species are found on piles among Hydrotds, sponges, etc.: Allorchestes littoralis Grubia compta Caprellidz Melita nitida Corophium cylindricun Microdeutopus gryllotalpa Elasmopus levis Stenothoe cvpris Gammarus locusta S. minuta On sandy shores the more common species are the following: Allorchestes littoralis T. megalophthalma Orchestia agilis Haustorius arenarius Talorchestia longicornis Unciola irrorata The more common species that are found on rocky shores between high- and low-water marks, and often in the greatest abundance, are the following: Orchestia agilis Elasmopus levis O. palustris Gammarus marinus Gammarus locusta Unciola irrorata Amphithoe rubricata O. agilis is especially abundant beneath masses of decaying sea weed. Gammarus locusta is more common under stones and among rockweed at low-water mark. dAimphithoe rubricata abounds in similar situations but apparently prefers Ulva to rock weed. Unciola irrorata is found only at low-water mark. MOVEMENTS. In general the Amphipoda are very agile and energetic except those species which inhabit tubes, usually of their own construc- tion, or lie buried in the sand or in’ excavations of wood, like Chelura. The most constant and uniform movement is that of the pleopods, by which a current of water is constantly passed forward over the gills. Besides these movements it has been observed in some species that the mouth parts move more or less regularly as if the animal were eating although there may be no food whatever in the water. In eating, the mouth parts of Orchestia agilis vibrate about 120 times a minute. 36 CONNECTICUT GEOL. AND NAT. HIST. survey. — [Bull. Although the Amphipoda possess three different kinds of locomotor organs, the pereiopods, pleopods, and uropods, which are used respectively for crawling, swimming, and leaping, it 1s only in a few species of Orchestiide that we find all three methods of locomotion employed. Unlike many of the higher crustaceans locomotion is always forward. The most general method 1s swimming. In order to obtain a start in swimming the animal usually extends the abdomen with some vigor — this part of the body being carried, when the animal is at rest, curled up beneath the body — and then maintains its motion by means of the rapid vibration of the pleopods. In swimming vertically, however, the abdomen frequently aids in the propulsion of the body, as in starting. While swimming, the body is well straightened, the antennz are held out in front of the body and move slightly as if exploring, and the pereiopods are held directed backwards. The animal seems to have some difficulty in maintaining its balance for it frequently rolls over and swims with its back or one side or the other downwards. . In walking or crawling there are two quite distinct methods. In those species whose bodies are depressed like Corophiui, for example, the body is easily maintained in an upright position and supported by the pereiopods. Where the body is strongly com- pressed, however, the upright position is with difficulty held and the last two pairs of pereiopods are bent outwards to brace the body. In these forms it is far more usual for the animal to lie on its side and progress by the alternate flexion and extension of the body with the corresponding movements of the pereiopods. Jumping is resorted to only by Orchestia and Talorchestia, and in these forms only when the animal is startled and must escape quickly. This act is accomplished by the uropods and the abdomen which is extended suddenly. Orchestia agilis can easily spring more than a foot into the air. The jumping is usually aimless and as a result the animal frequently falls upon an unfavorable spot. In climbing over algz and other irregularities of the bottom, many species employ their antenne as hooks for pulling the body, but the gnathopods are more generally used for this purpose. Burrowing has been studied most carefully by Miss Small- wood in Talorchestia which lends itself to the observation of this No. 26.] ARTHROSTRACA OF CONNECTICUT. 37 process by its preference when in a glass receptacle for burrowing along the side of the glass. Talorchestia burrows only in fine, loose sand, and when coarser sand or shell fragments are encountered below the surface the animal ceases to burrow. The second antenne are bent back sharply at the second joint and the head is pushed into the sand. The grains of sand are passed back from the first gnathopods to the anterior pairs of pereio- pods while the body is largely supported by the posterior pairs. The sand thus accumulates behind the body, which is more or less curled. At intervals the body is vigorously straightened and the sand projected some centimeters. As the burrow deepens, the sand is simply pushed behind the body by the pereiopods and the hole is closed. ; FOOD. The Amphipoda, so far as our knowledge goes, are voracious feeders, consuming all kinds of animal and vegetable matter, whether in the fresh condition or putrid. It is only rarely that they have been known to attack and consume living animals, but freshly killed animals are eagerly fed upon. By roughly estimat- ing the amount of fecal matter discharged by a single Ainphithoe supplied with an abundance of food (Ulva), Holmes concluded that in twenty-four hours about one-tenth of the body weight was consumed. The greater part of the food of the Amphipoda, probably because of its usually greater abundance, is vegetable; but molluscs, fish, and annelids as well as dead individuals of their own species are quickly consumed. The cast skin is fre- quently eaten, for in aquarium jars in the laboratory usually only small fragments of the molted skin are observed. The Amphipoda are not at all discriminating in their choice of food; bleached fronds of Ulva are consumed as readily as fresh green ones which may be lying beside them, and paint- covered straws from old brooms and paper will be eaten when there may be an an abundance of fresh sea weeds and animal tissues at hand. In eating, the food mass is held by the gnathopods and anterior pereiopods and chewed directly without first being torn apart by the gnathopods. When alge like Ulva are eaten, the frond is gnawed from the edge into an irregularly shaped excavation of 38 CONNECTICUT GEOL. AND Nat. HIsT. survey. [Bull rather smooth contour or from a central point where it is puckered or folded. ENEMIES, The principal enemies of the Amphipoda are undoubtedly fish. As noted in the section on the economic importance of the group, the Amphipoda form a very extensive source of food for many of our most highly valued fishes. Even the shore-inhabiting species, like Orchestia, frequently fall prey to Fundulus which come with the tide into every place where there is enough water to cover them and search for every possible material for food. The Amphipoda are usually in concealment when the tide is high but when one leaves its retreat it forms a tempting morsel for a fish. Besides fishes, the shore-inhabiting species must also be destroyed by birds. Although this has never actually been observed, forms of life far more active than the Amphipoda have frequently been seen to be pursued by birds in the same spots occupied by Orchestia and similar species. Miss Small- wood also describes an encounter which she observed between a half grown Orchestia palustris and one of the staphalinid beetles, in which the latter was victorious. The spiders, which occur in the same localities and occupy the same retreats as individuals of this species, must also serve to keep down the numbers. RESISTANCE TO ADVERSE CONDITIONS. The generally wide distribution of the Amphipoda may be partly accounted for by their power of resisting unfavorable environmental conditions. Many marine, as well as fresh-water, forms are able to survive under conditions which are fatal to almost all other groups. In examining material collected along the shore, it is frequently noticed that after molluscs, actinians, and worms decay, the Amphipoda still survive. Talorchestia, though not living in water normally, is dependent nevertheless upon it, for when placed in perfectly dry sand, specimens died in less than seven hours, while those placed in partially moistened sand in the laboratory survived ten or twelve days; when the sand is kept completely covered with water, it has been found that this species dies quite soon. Orchestia palustris may remain submerged for days without fatal results No. 26.] ARTHROSTRACA OF CONNECTICUT. 39 and yet the species normally abounds in fairly dry surroundings where individuals run about in the dry grass for several hours at atime. Specimens of Orchestia agilis I have found surviving after several hours on a dry laboratory floor in the summer. The shore-inhabiting forms must necessarily be able to endure considerable changes in the density of the water. Orchestia palustris will bear an exposure for several hours to fresh or brackish water. Talorchestia, according to Miss Smallwood, will bear exposure to spring water for six and a half hours without fatal results. MOLTING. The frequeney with which the Amphipoda molt is not known with any degree of certainty. Holmes found that in Amphithoe of the usual size two successive molts took place in seven or eight days. The frequency decreases as the adult size is gradually attained. In the process of molting the skin splits transversely along the line joining the head and thorax and on either side of the thorax between the upper margins of the coxal plates and the lower margins of the thoracic rings. The head and antennz are pulled backwards and the posterior part of the body is pulled forwards, the old skin remaining intact except along the splits just mentioned. The process may be completed in a quarter of an hour or so, or it may be prolonged over several days. Holmes notes one such case in which the animal died before the molt was completed. Immediately after molting, the animal is rather quiet but in a short time, a quarter of an hour, after the old skin has been shed, it assumes its ordinary activity. The antenne may become broken during this process but no other appendages have been observed to be lost at this time. NESTS AND NEST-BUILDING. Those species of Amphipoda which possess glandular pereio- pods habitually occupy tubes which serve as hiding places for them and from which it is rather difficult to drive them. Usually these tubes are cemented to some solid object, but Cerapus tubularis carries its tube about with it. These tubes are com- posed of a felt-like mass of fine threads which are secreted by 40 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. the glands of the pereiopods and spun as it were into the characteristic fabric. As the secretion emerges from the open- ing at the tips of the pereiopods it hardens immediately as in the spider’s web. Bits of algze and grains of sand are frequently woven into the tube which is thus rendered more inconspicuous. Smith has observed that in Microdeutopus bits of fecal matter are also worked into the web, but Holmes finds that Amphithoe does not use excrement to increase the tube but passes it out of the nest; accumulations of it usually being seen at both ends of the tube. The tubes are usually open at both ends and of uniform diameter throughout. Their length is as a rule considerably greater than that of the animal. In constructing a tube, the first two pairs of pereiopods are seen to be in rather rapid motion, passing back and forth over the space which the tube is to occupy. By rolling over and con- tinuing this motion the tubular form is attained. Amphithoe and various other species frequently leave their nests; they seem, however, to show no particular preference to return to those of their own making, but slip into any one that is unoccupied or proceed to build another, which is done in a re- markably short time, often in less than half an hour. Uniciola usually inhabits a tube, but has no spinning glands in its pereio- pods and has never been observed to weave a web for itself. The tube-dwelling forms habitually remain in their tubes with only the head and antenne thrust out. When disturbed Amphithoe retreats further into its tube and seeks safety in flight only when the intruding object is so persistent as to prevent further retreat into the depths of the tube. Holmes has observed Amphithoe dart out for food without letting go of its tube and quickly retract itself with the food in its gnathopods and devour it at leisure within its tube. The instinct to build tubes develops very early in life. A few days after leaving the brood-pouch, the yourig set about construct- ing nests like the adults, and exhibit precisely the same reactions to stimuli and habits. BREEDING HABITS. The eggs are discharged from the openings cf the oviducts, those from each orifice, according to Della Valle, becoming No. 26.] ARTHROSTRACA OF CONNECTICUT. 41 enveloped in a gelatinous capsule, so that when removed from the marsupium each egg mass retains its form. The young remain in the marsupium for some time after their escape from the egg and in some species it has been noted that the young return to the brood-pouch when forcibly removed from it. Observations are scarce regarding the length of time that the brood-pouch is occupied by the eggs and young, but in Orchestia palustris it may not be more than two weeks. Some specimens of Gammarus locusta kept in the laboratory were found to retain the eggs and young from two to two and a half weeks. From observations made on Amphipoda collected at Woods Hole as well as at Noank and New Haven, females were found carrying eggs on the following dates: Ayperia, Apr. 4 to June 3. Orchomenella pinguis, Jan. 23. Ampelisca spinipes, July 13 to Aug. 15. Byblis serrata, July 23. Stenothoe minuta, Aug. and Sept. Lafystius sturionis, Oct. 20 and Nov. 24. Calliopius leviusculus, Jan. 11, 22; April 1, 20, 27; May 6, at; July 215 Aug, 1, 6,293 Dec. 11, 25: Sympleustes glaber, April and July 13. Batea secunda, Aug. 23. Pontogeneia inermis, July 13. Melita nitida, Aug. 17. Elasmopus levis, Aug. 15, 17. Gammarus locusta, May 3; July 31; Aug. 6-19. G. annulatus, Mar. 6; Apr. I, 20, 27; May; June 21. Carinogammarus mucronatus, Aug. 14, 17. Orchestia agilis, May; June; first two weeks of July; Aug. 13 very few eggs. Orchestia palustris, July 9, 21. Talorchestia longicornis, June 14 (according to Bumpus, eggs in a late stage of development) to Aug. 13. (Miss Smallwood found the young free in the sand at Cold Spring Harbor and very few females bearing young by the end of July.) Allorchestes littoralis, Aug. 18. Microdeutopus gryllotalpa, July 13 to Aug. 18. ' 42 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. Leptocheirus pinguis, Aug. 10 to 18. Amphithoe rubricata, Aug. 6 to 17. A. longimana, Aug. 13 to 17. Grubia compta, July and August. Jassa marmorata, July 31 to Aug. 19. Ischyrocerus anguipes, April and July 17. Cerapus tubularis, July 4, 21. Ericthonius rubricornis, Aug. 10. Unciola irrorata, May 1; July 13: Aug. 9, 18. Corophium cylindricum, Jan. 5; July 17 to 21; Aug. 9 to 29. Caprellide, March, July, August, and September. The number of eggs deposited at one time varies greatly in different species. Observations have been made on a very few species so that our knowledge is limited. Orchestia agilis carries from seven to fifteen eggs, while one specimen of Calliopius leziusculus, whose odstegites are unusually large (Fig. 17), was found with nearly seventy eggs. Copulation seems to be in most cases an act quite independent of the sexual condition of the individuals, although females bearing eggs in the marsupium are practically never found with a male. Holmes has studied the copulating of several species arf finds that the recognition of the female by the male is purely the result of chance which brings the two sexes into collision with each other. That copulation takes place is due to the difference in the reaction of the two sexes when in collision. When two males collide both become active and for a few moments strive to grasp each other but because of the mutual activity fail to accomplish their end; when two females chance to meet, both roll up and become quiescent and in a few moments swim about as before. When, however, opposite sexes meet, both pursue the tactics described above with the result that the male grasps the female and swims off with her lying perfectly passive, her body strongly flexed. In all the species observed the female remains inactive save for the movement of the pleopods to main- tain a respiratory current. In copulation the male ordinarily retains his hold of the female by hooking the dactyls of his pereiopods beneath the edges of the coxal plates of the female; the gnathopods are used No. 26.] ARTHROSTRACA OF CONNECTICUT. 43 apparently only when a sudden disturbance renders the hold of the male insecure. The male carries the female thus for several days or probably much longer, and can with difficulty be separated without injuring him. Deposition of the eggs and fertilization have been observed rarely. Della Valle has described the process fully in Gammarus pungens, a fresh-water species of Europe. Deposition of the eggs takes place soon after molting and while the eggs are being discharged the male slips around the female so that their two heads are still pointing in the same direction but their ventral sides are directed toward each other and the openings of the vasa deferentia lie close to those of the oviducts. In this posi- tion the spermatic fluid is discharged over the eggs and fertilizes them. Immediately following the ejaculation the male returns to his former position with reference to the female. LIST OF SPECIES, In the following list an * indicates that a species is lilely to be met with in the State although up to this time it has been un- reported. A + indicates that a species is found in fresh water. Heavy-faced type indicates a species unreported hitherto from New England. HYPERIIDEA A. spinipes Boeck Hyperia galba (Mont.) Byblis serrata Smith GAMMARIDEA HAUSTORIIDAE LYSIANASSID.E Haustorius arenarius (Slabber) Lysianopsis alba Holmes PHOXOCEPHALID& Orchomenella pinguis (Boeck) Phoxvocephalus holbélli (Kr.) *Tmetonyx cicada (Fabr.) Paraphoxus spinosus Holmes T. quadratus sp. nov. *Harpinia plumosa (Kr.) *Hippomedon serratus Holmes uous *Anonyx nugax (Phipps) *Metopa grenlandica Hansen STEGOCEPHALIDE spaetnel *Stegocephalus inflatus Kr. — Stenothoe cypris Holmes IDE ; eevee S. minuta Holmes Ampelisca macrocephala Lill}. *4, compressa Holmes oe *A, agassizi (Judd) *Lafystius sturionis Kr. LAFYSTIID 44 CEDICERIDZ CONNECTICUT GEOL. AND NAT. JLIST. SURVEY. (Bull. tHyalella knickerbockert (Bate) *Monoculodes cdwardsi Holmes Allorchestes littoralis Stim. CALLIOPIID.© Calliopinus leviusculus (Kr.) *A pherusa gracilis Holmes PLEUSTID Sympleustes glaber (Boeck) PARAMPHITHOID.E *Epimeria loricata Sars BATEID.E Batea secunda Holmes PONTOGENEIIDA Pontogeneia inermis (Kr.) GAMMARIDE *tEucrangonyx gracilis (Smith) +Crangonyx tenuis Smith *Melita parvimana Holmes M. dentata (Kr.) M. nitida Smith Elasmopus levis (Smith) Gammarus locusta (Linn.) G. annulatus Smith G. marinus Leach Carinogammarus mucronatus (Say) +Dikerogammarus fasciatus (Say) DEXAMINIDE Dexamine thea Boeck ORCHESTIIDE Orchestia agilis Smith O. palustris Smith AORID.E Microdeutopus gryllotalpa Costa *M. danmoniensis (Bate) Lembos smithi (Holmes) PHOTID Photis reinhardi Kr. Podoceropsis nitida (Stim.) Leptocheirus pinguis (Stim.) AMPHITHOID Amphithoe rubricata ( Mont.) A. longimana Smith Grubia compta (Smith) JASSIDE Jassa marmorata Holmes Ischyrocerus anguipes Kr. COROPHIIDA Cerapus tubularis Say *Ericthonius rubricornis (Stim.) E. brasiliensis (Dana) Unciola irrorata Say Siphonecetes sntithianus Rathbun Corophium cylindricum (Say) CHELURIDE *Chelura terebrans Phil. CAPRELLIDEA Aeginella longicornis (Kr.) Talorchestia longicornis (Say) Caprella geometrica Say T. megalophthalma (Bate) Hyale prevosti (Milne-Ed.) *C. equilibra Say C. linearis (Linn.) HYPERIIDEA. Head not fused with first thoracic segment; maxillipeds with- out palp; coxal plates small or wanting; head generally large No. 26.] ARTHROSTRACA OF CONNECTICUT. 45 and tumid, with large, compound eyes which cover nearly the whole side of the head; gills on three or four thoracic segments ; last two abdominal segments fused, uropods usually with laminate rami, forming a tail fan. Hepato-pancreatic tubes two or none, rectal gland wanting; heart with two pairs of ostia, rarely three. Exclusively pelagic in habitat. Hyperia Latreille. Antenne in female very small, subequal. Mandibles with molar tubercle large, palp of moderate size with the second and third joints subequal in length. First max- ille with palp not greatly expanded, inner corner produced tc a tooth-like projection. Maxillipeds with outer plates obtuscly pointed, inner margin with small tufts of sete. Gnathopods scarcely chelate; carpus produced ventrally, especially in second pair. Pereiopods comparatively short, robust, and subequal in length. Uropods broad, with foliaceous rami. Telson large. Hyperia galba (Montagu). 1813. Cancer Gammarus galba, Montagu, Trans. Linn. Soe. London, vol. 11, p. 4, pl. 2, fig. 2. 1890. Hyperia galba, G. O. Sars. Crust. Norway, vol. 1, p. 7, pls. 2 and 3, fig. 1. Head much deeper than long, with reniform eyes covering whole lateral aspect ; back strongly arched. Antenne in female very short, subequal. Mandibles with long, slender three-jointed palp. Gnathopods small, scarcely chelate, and with only a few bristles; first pair with carpus having postero-distal angle ex- panded somewhat to form an acutely triangular lobe which is provided with a few sete; propodus oblong, slender, with poste- rior margin finely serrate; dactyl small. Second pair with carpus greatly produced at posterior apex, forming a slender triangular lobe which reaches beyond the middle of the propodus; the latter quite similar to that of the first gnathopod. Pereiopods subequal in length, robust, and almost devoid of setz ; coxal plates small; basal joint of each stout. Last two abdominal segments fused; uropods broad, with foliaceous rami; second pair not extending as far as the first; ter- il 46 CONNECTICUT GEOL. AND NAT, HIST, SURVEY. [Bu Fic. 4. Hyperia galba. minal pair with peduncle broader distally than proximally, with rather broad, sharply pointed, subequal rami. Telson slightly longer than broad, triangular. In the male the antennz exceed half the length of the body. Length 15 mm. According to Bovallius, Arctic specimens may attain a length of 20 mm. No. 26.] ARTHROSTRACA OF CONNECTICUT. 47 The species is abundant and widely distributed. It has been reported from the Arctic Ocean, Norway, Great Britain, France, Greenland, Nova Scotia, Grand Manan; Eastport, Maine; Salem, Woods Hole, Massachusetts; off Fishers Island, New Haven, Noank, Connecticut. It is found commonly in the jelly fish, Aurelia. Sars states that several individuals, males, females, and young, may occur in each medusa. Miss Rathbun in her List of the Crustacea of New England notes that Hyperia imedusarum has been found off New Haven and at Noank. In the material at my disposal I was unable to identify H. medusarum, and am inclined to believe that H. galba is the only Hyperid occurring in the waters of the State. GAMMARIDEA., Head not fused with first segment of thorax, and not tumid; maxillipeds with palp of 2 to 4 joints; coxal plates always well developed; eyes simple or compound, of various sizes, but never covering whole side of head; gills present on 5 or 6 segments; first uropod always biramus. Hepato-pancreatic tubes generally 4, occasionally 2; rectal glands 2 or 1, sometimes rudimentary ; heart with 3 pairs of ostia, rarely one pair. Typical Amphipoda. KEY TO THE GENERA OF GAMMARIDEA. A. Mandible not denticulated, palp 3-jointed; antenna 1 with stout peduncle and accessory flagellum well developed; coxal plates deep; gnathopod 2 elongated and slender, ischium elongated, propodus small and densely setose, dactyl rudi- mentary (Lysianasside). By “PESO - CMEITES drain c wxyetactied we acen at ba Wesloleue wdlgierten eee Lysianopsis p. 51 BB. Telson cleft. C. Postero-lateral angle of third abdominal segment not greatly produced. D. Mandibular palp inserted directly above molar tubercle Tmetonyx p. 54 DD. Mandibular palp inserted behind molar tubercle ..... CC. Postero-lateral angle of third abdominal segment Orchomenella p. 58 produced, with a deep sinus above. D. Peduncular joints of antenna 1 produced distally Hippomedon. 48 CONNECTICUT GEOL, AND NAT, HIST. SURVEY. [ Bull. DD. Peduncular joints of antenna 1 not produced distally Anonyx. AA. Without this combination of characters. B. Eyes simple, usually 4 (Ampeliscidz), C. Uropod 3 extending much beyond the others, telson ob- long and deeply cleft ...... 0c. cece ee eee Ampelisca p. 61 CC. Uropod 3 not extending much beyond the others, telson short and not deeply cleft. ..ccccc-caaacnsaces Byblis p. 67 BB. Eyes usually present, never more than one pair and never simple. C Peréiopeds: without dactyls s2sceycseudex sy Haustorius p. 70 CC. Pereiopods with dactyls. D. Rostrum produced into a hood over the antenne; pereio- pod 4 much longer than last pair (Phoxocephalide). E. EyeS) Wantine: sacinecies, ers Pay a aa e-ou eee eRe Harpinia. EE. Eyes: small ossaecindsaes cos caus Phoxocephalus p. 73 EBEs Fives. TARgE ssisse:ascsveccite'ssauans sla aie daubes Paraphoxus p. 75 DD. Rostrum not as above. E. Coxal plate 4 greatly enlarged to form large lateral shield. F.. Uropod 3 -biramows: 2.50 cease as Stegocephalus p. 60 FF. Uropod 3 uniramous. G. Mandibular palp small, 3-jointed ............ Metopa. GG. Mandibular palp wanting ......... Stenothoe p. 78 EE. Coxal plate 4 not greatly enlarged. F. Body depressed, rostrum large, broad not acute; no accessory flagellum; mandibular palp_ large; gnathopod 1 simple; gnathopod 2 weakly sub- Ghelate: seahite ean eeu ane od ceded Scat wack Lafystius. FF. Without this combination of characters. G. Last pereiopod the longest, dactyl styliform; eyes nearly contiguous above ...... Monoculodes p. 83 GG. Dactyl of last pereiopod not styliform. H. Gnathopod 1 rudimentary ............ Batea p. 89 HH. Gnathopod 1 not rudimentary. I. Pereiopods 1 and 2 without spinning glands J. Antenna 1 with calceoli. K. Last joint of peduncle of antenna 1 pro- duced to form a triangular process.. Calliopius p. 86 KK. Last joint of peduncle of antenna 1 not SO “PLOdUCEd sos wecan od Pontogeneia p. 91 JJ. Antenna 1 without calceoli. K. Mandible with palp; uropods 2 and 3 not enormously developed. L. Thoracic segments strongly tubercu- Late. yesh titer ercre otha hale ox dvbeaen Epimeria. No, 26.] ARTHROSTRACA OF CONNECTICUT. 49 LL. Thoracic segments not strongly tuber- culated. M. Postero-lateral margin of third ab- dominal segment serrated ........ Apherusa. MM. Postero-lateral margin produced to a single tooth, above which is a small sinus. N. Uropod 3 biramous Sympleustes p. 84 NN. Uropod 3 uniramous ..Unciola p, 165 MMM. Postero-lateral margin otherwise; accessory flagellum present; uro- pod 3 flattened and usually project- ing beyond the others; gnathopods subchelate, gnathopod 2 larger than 1 and larger in male than fe- male; telson small and flattened (Gammaride). N. Uropod 3 uniramous Crangonyx p. 95 NN. Uropod 3 biramous. O. Telson slightly emarginate. ..... Eucrangonyx p. 93 OO. Telson deeply cleft. P. Inner ramus of uropod 3 rudi- mentary, scale-like Melita p. 98 PP. Inner ramus of uropod 3 often smaller than outer, but not rudimentary. Q. Last 3 abdominal segments with fascicles of spines. R. Body with median carina.. Carinogammarus p. 113 RR. Abdominal segments 4 and 5 raised dorsally to spiniferous tubercles ... Dikerogammarus p. 105 RRR. Body without carina or tubercles Gammarus p. 107 QQ. Last 3 abdominal segments without fascicles of spines; uropod 3 with compara- tively broad, short rami .. Elasmopus p. 102 KK. Mandible with palp; uropods 2 and 3 enormously developed ..... Chelura p. 174 KKK. Mandible without palp; no accessory flagellum; uropods 2 and 3 normal. 50 CONNECTICUT GEOL. AND NAT, JLIST. SURVEY. [ Bull. L. Uropod 3 biramous; antenna 1 long ---- Dexamine p. LL. Uropod 3 uniramous; antenna 1 much shorter than antenna 2 (Orchestiida). M. Maxilliped with 3-jointed palp; an- tenna r shorter than peduncle of antenna 2, N. Gnathopod 1 of female subchelate Orchestia p. NN. Gnathopod 1 of female simple .. Talorchestia p. MM. Maxilliped with 4-jointed palp; an- tenna 1 longer than peduncle of antenna 2, N. Gnathopod 2 in male with carpus masked by merus ..... Hyale p. NN. Gnathopod 2 in male with carpus produced between merus and pro- podus. O. Telson undivided ....Hyalella p. OO. Telson cleft ....Allorchestes p. II. Pereiopods 1 and 2 glandular; coxal plate 4 not excavate behind. J. Gnathopod 1 much larger than gnathopod 2 (Aoride). K. Gnathopod 1 in male with carpus pro- longed to form a strong thumb-like PROCESS! 4 iceihiie wah Microdeutopus p. KK. Gnathopod 1 in male with carpus not so produced: weasencireraienaed Lembos p. JJ. Gnathopod 1 never much larger than gnath- opod 2, usually smaller. K. Uropod 3 biramous. ‘“L. Rami of uropod 3 not uncinate (Photidz). M. Rami of uropod 3 very unequal im GIZE hve Mecca een xcis bee Photis p. MM. Rami of uropods 3 not very un- equal in size. N. Antenna 1 with third joint of pe- duncle'shorter than first ....... Leptocheirus p. NN. Antenna 1 with third joint of pe- duncle longer than first ........ : Podoceropsis p. LL. Rami of uropod 3 very short, outer one uncinate. 115 118 122 126 128 131 133 136 139 143 I41 No. 26.] ARTHROSTRACA OF CONNECTICUT. 51 M. Lower lip with principal lobes notched (Amphithoide). N. Without accessory flagellum; uro- pod 1 with peduncle not produced below rami ...... Amphithoe p. 147 NN. Accessory flagellum present; uro- pod 1 with peduncle produced to spiniform process below rami Grubia p. 151 MM. Lower lip with principal lobes en- tire in front (Jasside). N. Gnathopod 2 in male with propodus having a thumb-like process; in female much larger than gnath- OPO. Ti: piace ss aes toot Jassa p. 154 NN. Gnathopod 2 in male without thumb-like process; in female not much larger than gnathopod 1 Ischyrocerus p. 156 KK. Uropod 3 uniramous (Corophiide). L. Uropod 2 uniramous ..?..... Cerapus p. 159 LL. Uropod 2 biramous. M. Gnathopod 2 in male complexly sub- CHEE: ooo Sites wa cccees Ericthonius p. 161 MM. Gnathopod 2 in male simply sub- chelate. N. Mandibular palp uniarticulate ..... Siphoneecetes p. 168 NN. Mandibular palp biarticulate .... Corophium p. 170 LYSIANASSID-A. Eyes usually large, compound. First antenne not longer than second pair; first joint of peduncle tumid; accessory flagellum always present. Mandibles with cutting edge not denticulate; molar tubercle seldom very robust; palp triarticulate. Second gnathopods slender, with ischium elongate, carpus and propodus spinulose, and dactyl minute. Terminal uropods biramous. Lysianopsis Holmes. Antenne short and differing little in the two sexes. Mandibles edentate, furnished with 3-jointed palp and a small molar process nearer the cutting edge than is the base of the 52 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. palp; first maxillee with narrow inner plate furnished with two apical sete, palp 2-jointed; maxillipeds with inner plate narrow and extending beyond middle of outer one, outer plate oval, inner margin devoid of spines; palp narrow. First gnathopods stout, simple; second gnathopods slender, ischium elongated, propodus short and setose, with dactyl very small, near middle of distal margin of propodus. Postero-lateral angle of third abdominal segment rounded. Uropods biramous. Telson entire. Lysianopsis alba Holmes. 1903. Lysianopsis alba, Holmes, Amer. Naturalist, vol. 37, p. 276. 1905. Lysianopsis alba, Holmes, Bull. Bur. Fish., vol. 24, Pp. 475, pl. 5, fig. 1. Interantennal lobes prominent and rounded; eyes large, oval. First antenne ‘short with basal joint of peduncle stout, and longer than the next two; principal flagellum a little longer than peduncle; accessory flagellum one-half the length of the principal one. Second antenne about as long as first, with flagellum as long as peduncle. First gnathopods simple, stout, basal joint broad; carpus somewhat inflated; propodus tapering distally, dactyl moderately stout. Second gnathopods very long and slender; merus densely setose on convex posterior margin; carpus long, with both front and hind margins convex, densely setose anteriorly; propodus subcordate, small, densely setose; dactyl very small. Posterior group of pereiopods increasing in length rapidly posteriorly, the last pair quite long and slender and having poste- rior margin of basal segment serrated; two preceding pairs with basal segments similarly serrated. Fourth abdominal segment slightly indented dorsally. First uropods extending further back than second, which extend further back than the third; rami of first pair nearly as long as peduncle, styliform; peduncle of last uropods very stout, longer than the rami and produced into a triangular projection at distal end of upper margin. Telson oblong, entire, rounded distally. No. 26.] ARTHROSTRACA OF CONNECTICUT. 53 is x 8 Color white or yellowish. Often the yellow or orange gonads may be seen through the integument. Length 6 mm. Fic. 5. Lysianopsis alba. 54 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bulk Holmes found the species in the mud at Woods Hole, Massa- chusetts, and off Nobska at the same place. In the Biological Survey of Woods Hole this species was dredged in 4 to 13 fathoms on bottoms of sand and gravel. It has also been collected within Connecticut at Noank in mud and gras’; off Stonington ; Long Island Sound. According to Holmes, the species has the habit of lying very quiet for a long time with its body strongly flexed and of starting quickly when disturbed and swimming vigorously for a time and then coming to a sudden stop with its body flexed as before. Tmetonyx Stebbing. Epistome more or less projecting and rounded in front. Antennz with small calceoli in male. Mandibles with large molar tubercle, obliquely truncate, with palp attached dorsal to it, second and third joints of palp sub- equal. First maxille with two sete on inner plate; outer plate broad and obliquely truncate; palp with several spine teeth apically. Second maxille with inner plate smaller than outer. Maxillipeds with outer plates large, oblong oval, reaching as far as second joint of palp which is not very robust. First gnathopods slender with propodus oblong and palm very oblique and rather indistinctly defined. Second gnathopods with ischium greatly elongated; propodus not at all produced beneath the minute dactyl. First pereiopods elongate, with large basal joint. Third uropods projecting beyond the second; rami minutely denticulate. Telson oblong, deeply cleft. The name Hoplonyx by which this genus was formerly known, was preoccupied as a coleopteran genus, Tmetonyx cicada (Fabricius). 1891. Hoplonyx cicada, G. O. Sars, Crust. Norway, vol. 1, P. 92, pl. 32, fig. 2. 1906. Tmetonyx cicada, Stebbing, Das Tierreich, Lief, 21, Pp. 74. ; Head with interantennal lobes only slightly projecting and rounded. Eyes not very large, narrow above, broader below. No. 26.] ARTHROSTRACA OF CONNECTICUT, 55 First antenne as long as head and first two thoracic segments together, with thick peduncle, the first joint of which is more than twice as long as the other two combined ; flagellum not quite twice as long as peduncle; accessory flagellum not quite half as long as flagellum, made up of seven joints. Second antenne half again as long as first pair; flagellum made up of about 28 segments. First gnathopods with propodus as long as carpus with palm somewhat arcuate and finely serrated but not defined below by prehensile angle. Second gnathopods with propodus half as long as carpus. Two posterior pairs of pereiopods rather elongated, with basal joint of moderate size. Anterior coxal plates more than twice as deep as respective segments and increasing in height posteriorly; fourth pair pro- duced below the posterior emargination to a narrow lobe, obtuse at the tip; fifth pair nearly as deep as broad. Third abdominal segment with postero-lateral angles drawn out to very short point. Last pair of uropods with inner ramus scarcely longer than basal joint of outer. Telson nearly twice as long as broad, slightly tapering distally and with two pairs of dorsal denticles, and very narrow cleft extending almost to the base. Length 15 mm. Distribution ; Arctic regions ; Norway; British Isles; Iceland; Greenland; Labrador; Woods Hole, Martha’s Vineyard, Massa- chusetts. The species ranges in depth to over 600 fathoms. Tmetonyx quadratus sp. nov. Head produced to a small rostrum; interantennal lobes rounded. Body stout. Eyes oval; deeply pigmented in alcoholic specimens. First antenne scarcely as long as head and first two thoracic segments together, with short peduncle about two-thirds as long as flagellum; first joint of peduncle large, more than half as broad as long; second and third joints short; accessory flagellum half as long as principal one and made up of six joints. Second antennz over a third as long as body; last two joints of peduncle subequal in length; flagellum with calceoli and made up of about twenty segments. 56 CONNECTICUT GEOL, AND NAT. HIST, SURVEY. [ Bull. First four coxal plates more than twice as deep as correspond- ing segments; first pair with front margin considerably shorter than hind one; first and second coxal plates with a minute triangular prolongation at the postero-ventral angle ; fourth plate deeply excavated behind to accommodate the fifth which is deeper than wide and bilobed. First gnathopods of male with merus with hind margin pro- longed distally and having several long spines and fine cilia; carpus triangular, as long as propodus and broader, with a dense patch of short cilia on the short hind margin; propodus subrectangular, with oblique palm which is slightly uneven and finely serrated, prehensile angle prominent and armed with two stout spines. Second gnathopods with short merus having a patch of dense cilia on the convex hind margin; carpus greatly elongated, broadening somewhat distally, with a patch of short cilia situated near proximal end of hind margin and one near distal end of front margin, which also bears several long sete; propodus only-slightly longer than wide, densely setose and pro- duced slightly to form a very weak chela with rudimentary dactyl. Third, fourth, and fifth pereiopods with basal joints expanded and serrated on posterior margins. Third abdominal segment with postero-lateral angle not pro- duced, but forming nearly a right angle. First and second uropods with styliform rami; the first pair extending beyond the second pair; third pair extending slightly beyond the first; rami foliaceous, inner one extending scarcely farther than basal joint of outer, inner margins of rami with sete, outer margins with short strong spines. Telson flat, twice as long as wide, cleft nearly to the base, each apex provided with a small spine. Length 13 mm. The species is represented by four specimens collected by Professor Verrill off Stonington, Connecticut, in April, 1873, in sand at a depth of “ 4-6 f.” It is distinguished from T. cicada by the shape of the eyes which in the latter species are narrow above and dilated below : by the presence of a definite prehensile angle on the propodus of the first gnathopod; by the form of the postero-lateral angle of 58 CONNECTICUT GEOL. AND NAT. ust. suRvEY. (Bull. the third abdominal segment; and by the greater length of the last peduncular joint of the first antenna. Orchomenella G. O. Sars. Coxal plates large. First antenne with moderately developed accessory flagellum ; second antennze in females slightly longer than first, not greatly elongated in male. Mandibles with slender palp, attached behind the small molar tubercle; first maxille with outer plate very obliquely truncated at tip; maxillipeds normal. First gnathopods strong, subcheliform; second gnathopods with short propodus which is dilated distally and densely setose, apex slightly produced beneath the minute dactyl. Pereiopods short, basal joint of last three pairs laminar. Terminal uropods in female scarcely reaching beyond the preceding pair, rami partly denticulated at the edges; in male only the outer ramus provided with sete. Telson reaching beyond peduncle of terminal uropods, oblong, triangular, deeply incised, lobes not widely separated. Orchomenella pinguis (Boeck). 1890. Orchomenella pinguis, G. O. Sars, Crust. Norway, vol. 1, p. 67, pl. 24, fig. 2. 1905. Tryphosa pinguis, Holmes, Bull. U. S. Bur. Fish., vol. 24, P. 473- Eyes rather large, elongated, not pigmented in alcoholic speci- mens. Interantennal lobes of head produced and narrowly rounded. First antenne short, with stout peduncle having second and third joints very short; first joint of principal flagellum elongated and densely setose, succeeding joints short; accessory flagellum moderately developed, four-jointed, extending beyond the third joint of principal flagellum. Second antenne much longer than first, especially in the male in which it scarcely equals one-half the body length; peduncle short; flagellum in male very slender. First gnathopods with deep coxal plate slightly narrower ventrally ; basal joint slender; carpus with narrow posterior lobe; propodus rectangular with palm nearly transverse and slightly No, 26.] ARTHROSTRACA OF CONNECTICUT. 59 Fic. 7. Orchomenella pinguis. convex. Second gnathopods ‘with propodus oblong, densely setose, postero-distal angle produced; dactyl,very small; carpus considerably larger than propodus with posterior margin strongly convex. Posterior pereiopods short with basal joints broadly suboval and shorter than rest of limb. Coxal plates large, those of first four appendages being more than twice as deep as their cor- responding segments; the fifth is much deeper than wide, with 60 CONNECTICUT GEOL. AND NAT, HIST. SURVEY. [Bull. posterior part of lower margin produced into a rounded lobe. First three abdominal segments with postero-lateral angles evenly rounded and with margin above angle minutely crenulated ; fourth abdominal segment with a rather deep dorsal depression near the anterior end. Terminal uropods with styliform rami; inner ramus more slender than outer and extending only as far as basal segment of the latter. Telson tapering distally and cleft to beyond the middle. Color whitish. Length, 5 mm. Distribution: Arctic regions; Norway; Greenland ; Labrador; Woods Hole; off Martha’s Vineyard; Long Island Sound. This species has been referred recently to the genus Tryphosa but it differs from the latter particularly in the position of the mandibular palp which is behind the molar tubercle ; in the carpus of the first gnathopod which is shorter than the propodus (in Tryphosa the two joints are more nearly of the same length) and in the propodus of the second gnathopod which is not pro- duced beneath the dactyl in Tryphosa. STEGOCEPHALID. Head short. Fourth coxal plates large. First antenne with accessory flagellum uni- or biarticulate. Second antenna seldom much longer than first. Lower lip without inner lobes. Mandibles without molar tubercle or palp. First maxille with inner plate with numerous sete. Second maxilla with inner plate very broad and setose, outer narrow, Gnathopods not subchelate. Third pereiopods with basal joint not expanded. Terminal uropods biramous. Telson small. Stegocephalus inflatus Kroyer. 1891. Stegocephalus inflatus, G. O. Sars, Crust. Norway, vol. 1, p. 198, pl. 69. Body tumid and smooth. Rostrum prominent, deflexed, and with a deep sinus below. Eyes wanting. First antennz with accessory flagellum having second joint minute. Mandibles with palp wanting. No. 26.] ARTHROSTRACA OF CONNECTICUT. 61 First five coxal plates greatly developed and presenting an evenly rounded contour below. First gnathopods stouter than second; propodus of both narrow. Last pereiopods with infero- posterior angle of basal joint produced and acute. Terminal uropods with lanceolate rami which are nearly twice as long as peduncle. Telson cleft beyond middle, strongly taper- ing in distal half. This species is extensively distributed in the Arctic and north Atlantic Oceans; Grand Manan; Eastport, Maine; South of Block Island; near Woods Hole, Massachusetts. AMPELISCID. Head truncate in front, no rostrum. Eyes simple, usually two pairs. First antennz without accessory flagellum. Second antenne attached far behind first pair. Gnathopods imperfectly subchelate, carpus never shorter than propodus; second pair longer and more slender than first. First and second pereiopods with very large merus; dactyl slender and elongate. Telson generally very deeply cleft. Ampelisca Kroyer. First coxal plate scarcely deeper than second, often concealing the base of second antenne; fourth obliquely truncate below posterior angle. Eyes four, or none, simple. Mandibular palp with second joint flattened and third joint linear and rather short. First maxilla with outer plate trans- versely truncated and palp having the terminal joint gradually expanded distally and armed at the apex with several strong teeth. Maxillipeds with inner plate oval; penultimate joint of palp nearly club-shaped and scarcely half as long as the second joint. Third and fourth pereiopods with very broad basal joint, carpus bearing a simple row of spines within hind margin; fifth pereiopods with basal joint greatly expanded and with ventral margin fringed with plumose sete; propodus foliaceous; dactyl lanceolate. 62 CONNECTICUT GEOL. AND NAT, HIST. SURVEY. [Bull. Terminal uropods reaching considerably beyond the others ; rami foliaceous, inner one broader than outer one. Telson oblong, cleft nearly to base. Ampelisca macrocephala Lilljeborg. Fic. 8. Ampelisca macrocephala. 1852. Ampelisca macrocephala, Lilljeborg, Ofvers. af Kgl. Vet. Akad. Forhandl., p. 7. 1895. Ampelisca macrocephala, G. O. Sars, Crust. Norway, vol. 1, p. 172, pl. 60, fig. 1. Head about as long as first three thoracic segments, frontal part produced and obliquely truncated at the tip. Eyes simple, two pairs, surrounded by bright red pigment in life; lower pair of eyes at antero-lateral angle of head. First antenne in female extending as far as peduncle of sec- ond pair; flagellum, twice as long as peduncle; in the male con- siderably longer. Second antenne of female scarcely more than No. 26.] ARTHROSTRACA OF CONNECTICUT. 63 half the length of body, last segment of peduncle shorter than preceding one. First pair of coxal plates widened distally and extending as far forward as the eyes. Propodus of first gnathopods oblong and not as wide as carpus, but about as long. Second gnathopods with very elongated carpus and propodus only half as long as carpus. First and second pereiopods with dactyl considerably longer than the two preceding joints combined. Last pereiopod with basal joint broadly rounded below; ischium broader than long; merus produced into a pointed setose lobe at lower posterior angle; carpus heart-shaped with three long ciliated sete on pos- terior angle, which is more produced than the corresponding an- terior one; propodus oblong, tapering distally, and scarcely longer than the two preceding joints combined; dactyl about as long as propodus. Third abdominal segment having the postero-lateral angle with a long, acute, slightly upturned projection, above which is a rounded sinus followed by a rounded lobe. Terminal uropods with rami broadly lanceolate and about twice as long as peduncle; second pair with outer ramus some- what shorter than inner and armed near the tip with a very long slender spine. Telson oblong oval, about twice as long as broad, deeply cleft, with four pairs of dorsal denticles and a single pair of apical spines. Color whitish. Length 15 mm. Distribution; Arctic regions; Greenland; Labrador; Iceland; British Isles; Casco Bay, Maine; Cape Ann, Woods Hole, Massachusetts ; Newport, Rhode Island; North of Fishers Island in 3%4-5 fathoms, Noank and New Haven (S. I. Smith), Connecticut. The species seems to be confined almost entirely to muddy bottoms and is abundant in eel-grass. Ampelisca limicola (Stimp.), recorded by Verrill (Am. Jour. Sci., ser. 3, vol. 10, p. 38) from the Noank region, is probably this species, according to an unpublished drawing of A. limicola by S. I. Smith. The individuals of this species agree with Holmes’s descrip- tion and differ from Sars’s figures of Norwegian specimens in 64 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. _[Bull. that the first pair of coxal plates project a little farther forward, the dactyl of the last pereiopod is as long as, or a little longer than, the propodus; and the dactyls of the first two pereiopods are a little larger. Ampelisca spinipes Boeck. Ren o TD Dy irs (\ \\ oN) = ee a Fic. 9. Ampelisca spinipes. 1860. Ampelisca spinipes, Boeck, Férhand. ved. de Skand. Naturf., vol. 8, p. 653. 1891. Ampelisca spinipes, G. O. Sars, Crust. Norway, vol. 1, Pp. 173, pl. 60, fig. 2. No. 26.] ARTHROSTRACA OF CONNECTICUT. 65 First antenne of female slightly longer than. peduncle of second pair and nearly half as long as body; first joint of peduncle rather stout; flagellum about three times as long as peduncle, with fascicles of slender sete; flagellum in male extremely slender and provided with very fine hairs. Second antenne in female half’ again as long as the first pair, last two joints of peduncle not - greatly elongated, subequal; in the male exceeding the length of body and with last joint of peduncle rather longer than preceding one. First gnathopods with propodus nearly as long as carpus and somewhat bulging on proximal portion of posterior margin. Second gnathopods very slender, the narrow carpus nearly twice as long as propodus. First and second pereiopods with dactyls about as long as pre- ceding two joints combined. Last pair with ischium nearly twice as long as wide, much longer than the nearly square merus; carpus subrectangular, elongated; propodus longer than carpus or dactyl. Postero-lateral angle of third abdominal’ segment not pro- duced, forming nearly a right angle; fourth abdominal segment of male with a prominent dorsal carina which ends abruptly posteriorly ; following segment deeply indented above; the cor- responding features in the female are much less pronounced. Second uropods with no long terminal spine on outer ramus. Terminal uropods thickly setose in the male but nearly devoid of setee in female.. Telson very narrow and nearly smooth, excepting for three small marginal spinules near tip of each terminal lobe. Color whitish, with a rose-colored or light-purplish spot in first coxal plate, and a few other spots of same color on other parts of the body. Length 14 mm. Distribution: Norway, North Sea, France; Woods Hole, Massachusetts; Newport, Rhode Island; off New London, Con- necticut; Fisher’s Island Sound, off Stonington, Noank, off Sea Flower Key, off Saybrook (Smith), Savin Rock (near New Haven), Long Island Sound. The species is quite abundant, being very common on sandy, gravelly, and muddy bottoms, and among eel-grass (Smith). It mecuis at depths up to 10-12 fathoms. 66 CONNECTICUT GEOL. AND NAT, IIIST. SURVEY. [Bull. It is probably the same as A. typica (Bate) which is recorded by Verrill (Am. Jour. Sci. ser. 3, vol. 10, p. 38) from the Noank region. He did not describe it. but a comparison of specimens so labelled in Peabody Museum as well as of an unpublished figure by S. I. Smith confirm this identity. Ampelisca compressa Holmes. 1903. Ampelisca compressa, Holmes, Amer. Naturalist, vol. 37; P- 273. 1905. Ampelisca compressa, Holmes, Bull. U. S. Bur. Fish., vol. 24, p. 480, pl. 6, fig. 1. This species I have never met with either at Woods Hole or along the Connecticut coast although Holmes states that it is the most common species of Ampelisca in the Woods Hole region. I quote Holmes’ description verbatim: “ Body strongly compressed and generally strongly flexed; head markedly shorter than first three segments of thorax; first antenne shorter than peduncle of second pair; third joint of peduncle a little shorter than first; flagellum only a little longer than peduncle, second antenne slender, over half length of body in female, and much longer than body in adult male; peduncle in male over a third length of body; last joint a little shorter than preceding one; first four coxal plates higher than their segments, the first considerably expanded below; first and second peraeo- pods with dactyl slender and longer than two preceding joints. Posterior pereeopods with basal joint widely expanded; ischium as broad as long; merus with a posterior lobe extending to middle of carpus. Postero-lateral angle of third abdominal segment broadly rounded; fourth abdominal segment in both sexes with a prominent dorsal crest which increases in height posteriorly and carries a pair of short sete on its posterior margin; terminal uropods similar in two sexes, furnished with only a few short spinules and sete; outer ramus of nearly same width throughout its length; telson about two-thirds as wide as long, lobes rather obtuse distally, but with inner angles subacute.” Length 6 mm.,; Distribution: Vineyard Sound; Newport, Rhode Island; off Block Island; Long Island Sound. It is found, according to Miss Rathbun, from the surface to depths of 47 fathoms. No. 26.] ARTHROSTRACA OF CONNECTICUT. 67 Ampelisca agassizi (Judd). 1896. Byblis agassizi, Judd, Proc. U. S. Nat. Mus., vol. 18, P. 599, figs. 9-11. This species is somewhat intermediate between Am~pelisca and Byblis, but agrees with the former genus in that the telson is much longer than broad and cleft nearly to the base, in the form of the last pereiopods, and in the fact that the last pair of uropods project much beyond the other ones and have no serrations on the opposing margins of the rami. It is distinguished from other species of Ampelisca found on the New England coast by the fact that the body is not unusually compressed, the postero-lateral angle of the third abdominal segment is not produced, the telson is broad and cleft nearly to the base, and the merus of the last pair of pereiopods is pro- duced distally nearly to the middle of the carpus. behind. The species was obtained by Mr. Judd by skimming the sur- face of Narragansett Bay at Newport, Rhode Island, in the summer of 1893. Byblis Boeck. Corneal lens, when present, two pairs. Antenne slender. Mandibles rather strong; second joint of palp not expanded, third joint short. Maxille as in Ampelisca. Maxillipeds with inner plate narrow and truncated at tip. Gnathopods very slender, especially the posterior ones. Last pair of pereiopods with basal joint produced posteriorly to a very large lobe fringed on anterior and ventral margins with short ciliated sete; propodus not at all expanded, sublinear; dactyl extremely narrow and tipped by two unequal bristles. Last pair of uropods scarcely reaching beyond the preceding pairs, rami narrowly lanceolate, not setose in female, their opposite edges being more or less distinctly serrated. Telson short and broad and only slightly incised posteriorly. Byblis serrata Smith. 1874. Byblis serrata, Smith, Rep. Com. Fish. for 1871-2, p. 56I. Eyes two pairs, simple, situated very far forward on the truncated head. 68 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. (Bull. First antenne in male less than one-half as long as body, extending beyond peduncle of second antenne; first joint of Fic. 10. Byblis serrata, peduncle stout and shorter than second joint which is cylindrical, last joint less than one-half as long as second; lower margins of No. 26.] ARTHROSTRACA OF CONNECTICUT. 69 second and third joints with many fascicles of sete; flagellum long and slender. Coxal plate of first gnathopod projecting considerably ante- riorly so that the mouth parts are hidden, lower margin serrate and armed with sete; second joint very long and slender; carpus longer than the propodus which is rectangular and three times as long as broad, posterior margin with sete and stout spines; dactyl stout. Second gnathopods with rhomboidal coxal plate which is provided with sete ventrally; carpus much longer than in first pair; propodus similar to that of first pair. Fourth coxal plate incised posteriorly, about as long as high. First and second pereiopods with spinning glands; merus very long and setose; carpus and propodus short; dactyl slender and longer than propodus. Last pair of pereiopods with basal joint expanded distally, posterior margin nearly straight, ventral margin evenly curved and reaching as far as distal end of carpus and provided with a fringe of sete; carpus as long as ischium and merus together, a little less than twice as long as broad, spinous on anterior and distal margins; propodus nearly as long as carpus, nearly four times as long as broad, with two transverse rows of spines and with distal margin having a long spine on each side of base of the long, slender dactyl. Third abdominal segment with postero-lateral angles rounded. Uropods biramous. First pair with equal rami, styliform and slightly longer than peduncle which bears a number of short spines dorsally. Second pair not extending as far as first; outer ramus shorter than inner. Third pair with equal rami which are longer than the peduncle and extend as far as first pair, inner margin of inner ramus provided with long sete, outer margin serrate, outer ramus with inner margin serrate. Telson slightly longer than broad, lateral margins evenly curved and converging rapidly to the evenly rounded extremity, cleft for more than half its length. In alcoholic specimens the coxal plates, bases of posterior pereiopods and sides of the abdomen are provided with large, irregular flecks of dark pigment. Length 10-12 mm, 70 CONNECTICUT GEOL, AND NAT. HIST. SURVEY. [Bull. Distribution: Woods Hole, Massachusetts; Newport, Rhode Island ; Fishers Island, New York; Fishers Island Sound ; Noank, Connecticut. The species has been found from the surface to 11 fathoms in Fishers Island Sound. Professor Smith found the species off Vineyard Sound and Buzzards Bay to a depth of 20-29 fathoms on bottoms of fine compact mud and sand. Judd in Proceedings of the U. S. National Museum, vol. 18, p. 596, 1896, describes the sexual differences of the species. HAUSTORIID/Z Coxal plates of moderate size, usually fringed with sete; fifth coxal plate bilobed. First antennz shorter than second, with accessory flagellum. Mandibles with cutting edge not dentate; secondary incisive plate and molar tubercle large, palp triarticulate. Gnathopods seldom powerful, weakly subchelate or chelate. Pereiopods often adapted for burrowing. Uropods all biramous. Telson flattened, more or less deeply cleft. Haustorius Statius Miller. First antennze with well developed accessory flagellum. Second antennz longer than the first; fourth joint of peduncle laminarly expanded. Mandibles with rather large palp. First maxille with densely ciliated flap-like expansion outside outer plate; palp well devel- oped. Maxillipeds with inner and outer plates of nearly equal size ; palp with second joint produced at end interiorly to rounded lobe, third joint bent to a right angle, fourth joint wanting. Gnathopods comparatively feeble; propodus of first simple; that of second pair forming a minute chela. Two anterior perei- opods with carpus having a rounded, lamellar expansion poste- tiorly. Three posterior periopods very wide. Dactyls wanting in all pereiopods. Uropods, first pair with both rami coarsely spinous at trun- cated tips; second pair with rami setose; last pair with rami slender and linear, the outer biarticulate and longer than inner. Telson broad, slightly incised in middle. No. 26.] ARTHROSTRACA OF CONNECTICUT. 71 Haustorius arenarius (Slabber). 1818. Lepidactylus dityscus, Say, Jour. Acad. Nat. Sci. Phila., vol. 1, p. 380. 1906. Haustorius arenarius, Stebbing, Das Tierreich, Lief. 2I, p. 125. Fic. 11. Haustorius arenarius, Head as long as first two segments of body, with short, tri- angular rostrum; eyes small and nearly round, inconspicuous in alcoholic specimens. 72 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. First antennz as long as head and first two thoracic segments together ; peduncle with second and third joints expanded distally and together longer than the first joint, provided with numerous plumose setze; accessory flagellum over half as long as principal one which is scarcely as long as peduncle. Second antenne longer than first and having the last two joints of the peduncle greatly dilated and with inferior margin strongly convex and provided with abundant plumose setz, penultimate joint much longer than last one and with a rounded distal lobe extending one-third as far as last segment; flagellum shorter than peduncle and made up of about ten segments. Body somewhat depressed. First four coxal plates increasing successively in size poste- riorly, over twice as deep as corresponding body segments. First three tapering below to rather obtuse points; fourth one rounded below and much larger than others. Gnathopods weak; first pair with carpus longer than propo- dus and dactyl, and with posterior margin evenly convex and provided with long setz; propodus simple; dactyl short. Second gnathopods very slightly longer than first, propodus very slender and chelate; dactyl very small. Dactyls wanting in all the pereiopods. First and second pereiopods small and subequal with carpus broader than long, due to a rounded lobe on posterior margin; propodus dilated distally; third pereiopod considerably larger than second and with greatly expanded basal joint and merus and carpus dilated transversely; fourth pereiopod largest, with basal, meral, and carpal joints greatly expanded; fifth pereiopod with basal joint broader than long and with anterior and posterior margins very strongly convex, merus with a very long lobe projecting posteriorly which is armed with sharp spines and plumose setz. Uropods biramous; second pair smallest ;: terminal pair not projecting quite as far as first pair, outer ramus biarticulate. Telson short and broad, strikingly bilobed, with sete on distal and outer margins. The color according to Bate is pale grayish yellow, resembling somewhat closely the sand in which it lives. Length 18 mm. Distribution: Georgia to Cape Cod. Specimens have been found at New Haven, Connecticut. No. 26.] ARTHROSTRACA OF CONNECTICUT, 73 This species occurs on sandy shores, where the animals burrow near low-water mark with great dexterity, being by far the most rapid burrowers among the Amphipoda. It is also occasionally found under stones in sandy places, and is dredged in shallow water, It can not easily be confused with any other Amphipod be- cause of its broadly expanded pereiopods devoid of dactyls. PHOXOCEPHALID. Rostrum projecting like a hood over bases of antenne. Coxal plates rather large. First antennz with accessory flagellum well developed. Mandibles with cutting edges distinctly developed, molar tubercle not large; palp large. First maxille with inner plate small, palp uni- or biarticulate. Maxillipeds. with plates small and palp large. First and second gnathopods generally similar in form, sub- chelate, large. Fourth pereiopod the longest. Terminal uropods often varying sexually, outer ramus the longer, biarticulate. Telson deeply cleft. Phoxocephalus Stebbing. Head with acute hood. First antennze shorter than second which in the male are very elongated and slender and bear calceoli on the flagellum. Mandibles with molar tubercle distinctly developed; palp well developed. First maxille with very small uniarticulate palp. Second maxille with the plates nearly equal. Maxillipeds with outer plate scarcely larger than inner; palp with fourth joint slender. Gnathopods unequal, the posterior ones being the larger. Third pereiopods with basal joint laminarly expanded; last pair with basal joint very large. Last uropods in female with inner ramus naked and much shorter than outer ; those in male much larger with both rami well developed, lanceolate, furnished marginally with ciliated sete. Lobes of telson narrow. 74 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. Phoxocephalus holbélli (Kroyer). 1842. Phoxus holbélli Kroyer, Naturh. Tidsskr., vol. 4, Pp. ISI. 1888. Phoxocephalus holbélli, Stebbing. Rep. Voy. Chal- lenger, vol. 29, p. 1717. 1891. Phoxocephalus holbolli, G. O. Sars. Crust. Norway, vol. 1, p. 144, pl. 49. Fic. 12. Phoxocephalus holbélli, Body smooth, Head produced forward to form an acute, triangular hood over antenne; eyes poorly developed, incon- spicuous. First antenne with first joint of peduncle thick and longer than second and third together, and with a triangular process distally; principal flagellum 6-jointed; accessory flagellum 3- jointed. Second antenne with penultimate joint of peduncle enlarged distally and considerably longer than last joint and armed with many long sete and several spines; flagellum 6- No, 26.] ARTHROSTRACA OF CONNECTICUT. 75 jointed in female, with first joint as long as second, third, and fourth together. Coxal plates of first and second gnathopods rectangular, higher than wide, with several long sete on posterior portion of lower margin. Gnathopods of same form except the carpus of first is longer than that of second; propodus of second slightly longer than that of first, oblong in form but slightly broader distally, palm oblique and convex, separated from hind margin by prominent triangular process and spine; carpus with three sete on hind margin. Third pereiopod with basal joint broader proximally than distally and with front margin slightly concave; fourth pereiopod about one-half as long as body, basal joint provided with numerous sete on anterior margin; fifth pereiopod with basal _ joint as long as rest of limb and as broad as long, posterior margin strongly convex and finely serrate. Postero-lateral angle of third abdominal segment narrowly rounded. Uropods biramous with rami narrowly lanceolate. In female, terminal uropod with inner ramus scarcely half as long as outer, second joint of outer less than half the length of first; in male, rami nearly equal, plumose, outer ramus with three spines on outer margin. Telson much longer than broad, cleft to the base, narrowed distally, with two spines and a seta on each rounded apex. Golor light buff or orange. Length 5 mm. Distribution: Arctic regions; North Atlantic coast of Europe; Greenland ; Labrador; Grand Manan; Bay of Fundy; Casco Bay; Vineyard Sound in deep water (Smith) ; Newport, Rhode Island; Long Island Sound. Low water to 45 fathoms. Paraphoxus G. O. Sars. Hood evenly vaulted, not carinated. Antenne in female nearly equal-sized; second ones in male not very elongated, flagellum very slender, provided with calceolt. Mandibles with very poorly developed molar tubercle; palp extremely slender. First maxilla with palp larger than in Phoxo- cephalus but still uniarticulate. Second maxille with inner lobe 76 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. smaller than outer. Maxillipeds with inner plates obtusely rounded at tip; third joint of palp oval; fourth joint very slender and curved. Gnathopods exactly alike in size and form, propodus oval, constricted at base. Pereiopods as in Phoxocephalus. Last pair of uropods dissimilar in the two sexes, compara- tively simple in the female with inner ramus much shorter than outer; in male much larger, with both rami well developed and fringed with ciliated sete. Telson with narrow lobes. Paraphoxus spinosus Holmes. 1903. Paraphoxus spinosus, Holmes, Amer. Naturalist, vol. 37, p- 276. 1905. Paraphoxus spinosus, Holmes, Bull. U. S. Bur. Fish., vol. 24, p. 477. Head produced into triangular rostrum which projects be- yond the basal joint of the first antennz. Eyes large in male, much smaller in female. First -antenne very short, only slightly longer than peduncle of second antenne of male; peduncle stout ; flagellum shorter than peduncle; accessory flagellum well developed. Second antennz in male with stout peduncle and very long slender flagellum con- siderably more than one-half as long as body, made up of elongated segments which bear calceoli. In female the flagellum of the second antenne is scarcely longer than peduncle. First four coxal plates gradually increasing in depth poste- riorly ; fourth pair much larger than the others, with hind margin incised; first to third pairs rhomboidal, with a few fine sete on postero-ventral angle. Gnathopods similar in size and shape; second joint rather slender; carpus longer than propodus, stouter at distal than at proximal end; propodus broader distally than proximally; palm nearly transverse and marked off from posterior margin by a triangular process which bears a spine; dactyl very slender. First and second pereiopods subequal ; merus stout and longer than carpus which is tapering and armed distally with a very long curved spine; propodus slightly longer than carpus, with three or four short spines on hind margin; dactyl very small and spine-like. Fic. 13. Paraphoxus spinosus. 78 CONNECTICUT GEOL. AND NAT. HIST, SURVEY. [Bull. Third pereiopod stout with basal joint well expanded and sub- rectangular in form; fourth, fifth, and sixth joints very stout, and subequal in length, dactyl very small. Fourth pereiopods also stout; basal joint broader than in preceding appendage and more rounded; propodus much longer than carpus. Fifth pereio- pod somewhat smaller than preceding twa; second joint broadly expanded posteriorly and with hind margin dentate. Posterior margin of lateral expansion of third abdominal segment furnished with a few setz. First uropod with peduncle long and slender and provided near distal end with a few spines; rami styliform and somewhat shorter than peduncle. Second uropod shorter and stouter than first with peduncle and rami provided with numerous spines. Third uropod extending beyond others; peduncle short; rami in male subequal and laminar, provided on margins with numerous plumose setz, outer ramus with short distal joint. In female outer ramus much larger than inner and biarticulate with- out plumose sete. Telson subrectangular, incised nearly to base; lobes evenly rounded and provided toward lateral aspect with two very short spines. Length 4.5 mm. Distribution: Newport, Rhode Island (S. D. Judd) ; off Stonington, Noank, Noank Harbor (surface), Connecticut ; Long Island Sound. STENOTHOIDA. Similar to the Metopide except as follows: Mandibles without molar tubercle or palp. First maxille with biarticulate palp. Maxillipeds with inner plates small; outer plates obsolete. Stenothoe Dana. Coxal plates of moderate size except fourth which is greatly produced posteriorly and covers to a great extent the succeeding pairs. Antenne elongated and as a rule subequal in length. Mandibles without palp and with molar tubercle obsolete. First maxille with palp large and biarticulate. Maxillipeds with No. 26.] ARTHROSTRACA OF CONNECTICUT. 79 inner plates small and narrow; palp elongated, with unguiform fourth joint finely ciliated inside. First gnathepods as a rule much smaller than second and subcheliform. Third pereiopods with basal joint linear, merus of last two pairs laminarly expanded. Last pair of urepods elongated. Telson well defined, squamous, entire. Stenothoe cypris Holmes. Fic. 14. Stenothoe cypris. 1903. Stencthoe cypris, Holmes, Amer. Naturalist, vol. 37, p. 278. 1905. Stenothoe cypris, Holmes, Bull. Bur. Fish., vol. 24, p. 484. ; Eyes round and deeply pigmented in alcoholic specimens. Antenne subequal in length and about one-third the length of body ; first pair with first joint of peduncle very stout and nearly as long as next two joints; flagellum about as long as peduncle and made up of about six joints, the first of which is as long as the last joint of peduncle. Second antenne with long slender peduncle having last two joints subequal and third joint of 80 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. peduncle not much longer than broad; flagellum of about six joints. First gnathopods simple; basal joint long and slender with short sete on outer margin; merus widened and rounded distally with distal half of posterior margin provided with short sete and two pectinate spines; carpus shorter than propodus and of uniform diameter; propodus slightly tapering. Second gnatho- pods larger than first, with well developed oval coxal plate ; basal joint slightly longer than that of first pair; merus broader at distal than at proximal end and with hind margin much longer than anterior one; carpus broader than long and with a narrow rounded lobe bearing a few pectinate spines projecting posteriorly farther than preceding joint; propodus: oblong, widest behind the palm which is quite oblique and bears a stout spine near hind margin. First pereiopods with well developed oval coxal plate as large as that of second gnathopod. Coxal plate of next pereiopod enormous, equalling the first six segments in length, oval in out- line, much broader than deep. Coxal plates of succeeding pereio- pods small and rounded. First uropods with peduncle nearly twice as long as the sub- equal, lanceolate rami; second pair not reaching as far as the first pair and with peduncle slightly longer than the subequal lanceolate rami. Third pair with peduncle equal to the single ramus which is composed of two unequal segments. Last two abdominal segments fused. Telson entire, acute. Holmes states in his description that the coxal plate of the first gnathopod is well developed and that of the first pereiopod is small. This is evidently an error for in specimens from Long Island Sound the condition is reversed, the coxal plate of the first pereiopod being well developed and that of the first gnatho- pod very small. I quote Holmes’ description of the color and habits of the species : “ Body pellucid ; first segment more or less rose-colored above, a row of rose-colored or sometimes brownish spots or bars along middle of back; eyes rose-colored; joints of peduncle of antennz yellowish at tip; a dark bar across tip of abdomen and base of No. 26.] ARTHROSTRACA OF CONNECTICUT. 81 uropods ; gills with a tinge of rose color. . . . . This species swims in an irregular, jerky manner and after swimming but a short distance suddenly stops, flexes the body, and drops to the bottom. Its motions in the water resemble those of the ostracod, Cypris.” Length 2 mm. Distribution: Woods Hole, Massachusetts; Long Island Sound. Holmes obtained this species in material secured from piles at Woods Hole in September and also among masses of Pennaria. Stenothoe minuta Holmes. per, 7 Fic. 15. Stenothoe minuta. 1903. Stenothoe minuta, Holmes, Amer. Naturalist, vol. 37, p. 278. 1905. Stenothoe minuta, Holmes, Bull. Bur. Fish., vol. 24, p. 485. Eyes round. Antennz subequal in length and a little over one-half as long as body; first joint of first pair very much thicker than second and nearly as long as second and third; flagellum slender, about twelve-jointed. Second antennz with last two joints of peduncle of nearly equal length; flagellum with somewhat fewer joints than first, pair. 6 82 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. First gnathopods with coxal plates small; basal joint with a few slender spines on anterior margin; merus rounded below, where it is furnished with four spine-like setae and several much shorter ones; carpus produced posteriorly into a rounded lobe which has about three large spine-like sete at its distal end; propodus nearly twice as long as wide, palm very oblique and minutely pectinated like inner margin of dactyl. Second gnatho- pods larger than first; coxal plate large; basal joint more or less sigmoid; merus produced below into stiff setee and three large spines at the tip; propodus widest across distal end of palm which is oblique, only slightly curved, not pectinated, and armed at distal end with two or three pairs of spines. Pereiopods of sub- equal length; posterior pairs with basal joints considerably ex- panded, and merus rather broad and produced downward at postero-inferior angle; dactyls of all pereiopods large. Fourth coxal plate not unusually large for the genus, scarcely ovate. First uropods long and slender with lanceolate rami subequal and nearly equal to peduncle; outer ramus of second uropods markedly shorter than inner; the single ramus of terminal uro- pods about as long as peduncle, with proximal joint a little shorter than conical terminal one and armed with a spine at distal end of upper margin; peduncle with a spine above near middle and a spine at distal end. Telson flattened, oblong, pointed, entire, with three small spines near lateral margins. Color pellucid, marked with scattered reddish-brown spots. Length about 2.5 mm. Distribution: Woods Hole, Long Island Sound. Holmes found it among seaweed and on piles. GDICERIDA. Eyes, when present, usually contiguous above. First antenne with accessory flagellum absent or rudimentary. Mandibles with palp usually large, First gnathopods subchelate. Second pair subchelate or rarely chelate. Last pereiopods very large with dactyl styliform. Uropods commonly extending back to the same distance. Telson small, entire. No. 26.] ARTHROSTRACA OF CONNECTICUT. 83 Monoculodes edwardsi Holmes. 1903. Monoculodes edwardsi, Holmes, Amer. Naturalist, vol. 37; P- 275. ' 1905. Monoculodes edwardsi, Holmes, Bull. U. S. Bur. Fish., vol. 24, p. 487. Eyes nearly contiguous above and situated in front of base of rostrum, which is triangular and curved downwards. First antennze without accessory flagellum, shorter than second pair. Mandibles with second joint of palp bent inwards and about as long as third joint. First maxille with inner plate suboval and bearing two sete at tip; first joint of palp longer than broad, second joint spatulate. Maxillipeds with inner plate smalf and oblong, not reaching the distal end of first joint of palp; outer plates reaching only a little beyond the middle of the broad second joint of palp. First gnathopods with carpal lobe long and distally setose; propodus oval, with palm evenly convex. Second gnathopods with a slender carpal process which scarcely extends beyond the middle of .the palm. Coxal plates unusually small. Anterior pereiopods with carpus prolonged into a long lobe which extends behind the short propodus. Last pair of pereiopods much longer than the preceding, with very long, styliform dactyl. ; Rami of last pair of uropods a little longer than peduncle. Telson oblong and distally rounded. Length 9 mm. Distribution: Woods Hole, Massachusetts and Newport, Rhode Island. PLEUSTIDA. Rostrum more or less prominent. Fifth to seventh coxal plates small. First antennz without accessory flagellum, longer than second pair; flagellum in both pairs made up of many segments. Mandible with third joint of palp falciform. First maxille with inner plate small. Maxillipeds with inner and outer plates small and not strongly armed, and with palp long. First and second gnathopods often alike, subchelate. Third to fifth pereiopods with basal joint expanded. 2 84 CONNECTICUT GEOL. AND NAT. Hist. suRvEY. — [ Dull. Third uropods with rami longer than peduncle, slender, lanceo- late, spinulose; outer ramus shorter than inner. Telson small, entire or (very rarely) notched, boat-shaped. Sympleustes Stebbing. Rostrum small, coxal plates moderate. Mandibles with molar tubercle cylindrical and with large palp, the last joint of which is falciform. First maxille with well developed palp slightly dilated distally ; inner plate with two sete apically. Maxilipeds with broad inner plates; outer plates small; palp with fourth joint small. Second gnathopods larger than first and more pronouncedly subchelate. Terminal uropods elongated with inner ramus longer than outer. Telson small, entire. Sympleustes glaber (Boeck). 1861. Amphithopsis glaber Boeck, Forh. Skand. Naturfor., vol. 8, p. 662. 1899. Sympleustes glaber, Stebbing, Ann. and Mag. Nat. Hist., ser. 7, vol. 4, p. 209. Head projecting to form a small rostrum, lateral angles rather prominent and acute. Back evenly rounded. Eyes large and irregularly circular. First antenne longer than second, about two-thirds as long as body ; first joint of peduncle large, cylindrical, bearing a tooth-like process on ventral distal angle ; second and third segments shorter than first; flagellum long and multiarticulate. Second antenne with last two joints of peduncle equal in length; flagellum long and slender. First four coxal plates deeper than wide and increasing in height posteriorly, first three with small tooth-like projection at postero-inferior angle; fourth rather deeply incised posteriorly. Fifth, sixth, and seventh coxal plates low. First and second gnathopods not very unlike in form or size, first slightly smaller than second. Fourth joint with small tri- angular process at postero-distal angle and with distal margin provided with several long sete; carpus triangular, shorter than propodus and about as broad, posterior angle rounded and with No. 26.] ARTHROSTRACA OF CONNECTICUT. 85 many slender sete; propodus irregularly oval, palm convex and considerably longer than posterior margin, provided with several spines and numerous sete; dactyl long and slender. Fic. 16. Sympleustes glaber. Pereiopods subequal in length; third, fourth, and fifth with second joint expanded with posterior margin well rounded and serrate. Fourth joint of last 3 pereiopods with postero-distal angle acute; sixth joints longer than the corresponding ones of first and second pereiopods. Third abdominal segment with postero-lateral angle in form of a small slightly upturned tooth with a concavity above it. First uropods slender, with peduncle considerably longer than rami which are acuminate, dorsal margin of peduncle and rami with short spines; second uropods of same form as first but peduncle considerably shorter, outer ramus shorter than inner; third uropods not extending as far posteriorly as second, outer ramus much shorter than inner. 86 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. Telson small, oval, twice as long as broad and rounded distally. Length 6 mm, Distribution: Arctic Ocean, Greenland, Iceland, Norway, Fishers Island Sound, Long Island Sound, off Stonington, Connecticut. CALLIOPHD-., Coxal plates not large. First antenne with peduncle usually short and accessory flagellum uniarticulate or wanting. Mouth parts varying slightly from the normal. First and second gnathopods usually feeble, subchelate: Marsupial plates of female large and broad. Terminal uropods with inner ramus longer than outer. Telson entire, sometimes a little notched or emarginate. Calliopius Lilljeborg. Antennz stout, subequal in length, both having flagella divided into numerous short and sharply defined articulations carrying large calceoli ventrally, last peduncular joint of first antennz produced to a triangular process which also bears calceoli; accés- sory flagellum wanting. Mandibles with comparatively large palp in which the terminal joint is as long as the second. Gnathopods strong, with short carpus produced posteriorly to a setiferous lobe; propodus large with palm occupying nearly its entire length and imperfectly defined. Last uropods scarcely reaching beyond the others, peduncle comparatively short, rami subequal and lanceolate. Telson not incised at tip, tongue-like. Calliopius leviusculus (Kréyer). 1838. Amphithoe leviuscula, Kréyer, Kongel. Danske Videns-Kabernes Selskabs Skrifter, Copenhagen, vol. 7, p. 281, pl. 3, fig. 13. 1871. Calliopius leviusculus, Boeck, Forh. Videnskabs- Selskabst, Christiania, 1870, p. 197. 1906. Calliopius leviusculus, Stebbing, Das Tierreich, Lief. 21, p. 296. Eyes large, reniform. Fic. 17. Calliopius leviusculus. First antennze shorter than second and with first joint of peduncle considerably thicker and a little longer than second; third joint with a conspicuous triangular process projecting below flagellum and bearing about eight calceoli on lower margin; flagel- lum longer than peduncle, with joints produced at antero-inferior angle and each provided with a pair of calceoli and several olfactory sete on lower side. Second antenne with last two joints of peduncle subequal in length, the fourth joint extending as far as the second joint of first antenne; flagellum subequal to peduncle, joints not produced below, furnished with calceoli. 88 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. First four coxal plates deeper than broad and about as deep as their respective segments and increasing successively in depth. First and second gnathopods of similar form and nearly equal size, the second being a trifle the larger, and with the lobe on the posterior side of carpus longer and narrower than in first; propo- dus ovate, palm very oblique with a row of stout spines on outer side which begins a little beyond the middle of the palm. First two pairs of pereiopods with merus strongly produced downward at anterior angle; last three pereiopods with merus strongly produced downward at posterior angle, that of last pair being more dilated than in the preceding ones. First three abdominal segments more or less produced at posterior end to forma keel, especially developed in older speci- mens, and second, third, fourth, and sometimes also first de- pressed in front. Postero-lateral angles of second and third seg- ments with a small tooth. First uropods with outer ramus markedly shorter than inner which is a little shorter than the peduncle, both margins of peduncle and rami armed with numerous short spines; second uropods with peduncle relatively broader than that of first and somewhat shorter than inner ramus, outer ramus much shorter than inner; terminal uropods extending beyond the others, rami flattened, lanceolate, subequal, much longer than peduncle with both margins of each furnished with numerous spines and plumose sete. Telson oblong, slightly tapering and rounded at tip. Length 13 mm. Distribution: Greenland, Labrador, Halifax, Arctic regions, Norway, British Isles, Narragansett Bay (Judd), Vineyard Sound (Smith), Woods Hole, Gloucester, Long Island Sound. The species is largely pelagic and is often taken in large numbers on the surface at Woods Hole, especially in the winter. BATEID2. Head strongly rostrate. First coxal plate rudimentary. First antenne without accessory flagellum. Mandibles with palp. First gnathopods degraded, without propodus or dactyl. Telson cleft. No, 26.] ARTHROSTRACA OF CONNECTICUT. 89 Batea Fr. Miller. Head with strong rostrum. First antennz without accessory flagellum and a little shorter than second. Mandibles with palp. Maxillipeds with outer plates fully reaching apex of second joint of palp, fringed with spine teeth on inner margin. First gnathopods with coxal plate rudimentary, ending with a feeble linear basal joint which is longer in female than male. Second gnathopods subchelate. Third to fifth pereiopods with basal joint expanded. Second uropods shorter than first or third; last uropods with short peduncle and flattened rami. Telson short and deeply cleft. Batea secunda Holmes. Fic. 18. Batea secunda. 1903. Batea secunda, Holmes, Amer. Naturalist, vol. 37, p. 284. 1905. Batea secunda, Holmes, Bull. Bur. Fish. for 1904, vol. 24, P- 499. ; : Head with a rather prominent narrow rostrum. Eyes very large. go CONNECTICUT GEOL. AND NAT. ILIST. SURVEY. [ Bull. First antennz nearly as long as second; first joint of peduncle much stouter and a little longer than second; third joint small, less than half the length of second; flagellum consisting of about eighteen elongated segments. Second antenne nearly half as long as body with last two joints of peduncle of nearly equal length. First gnathopods consisting simply of a rudiment of the coxal plate and basal joint, of which the former is very small and the latter is curved and rounded distally where it is provided with a few curved sete. Second gnathopods slender; carpus with a large, triangular posterior lobe; propodus with oblique palm, only slightly curved and minutely denticulated ; dactyl with four spini- form projections on inner margin behind tip. Second, third, and fourth coxal plates about as deep as their respective segments ; that of second pereiopod broader than deep and deeply excavated at upper posterior margin; the three posterior pereiopods in- creasing successively in length; basal joints broad; last pair con- siderably longer than preceding. Posterior margin of third abdominal segment with several upturned teeth above the rounded postero-lateral angle. First two pairs- of uropods with styliform rami, and outer ramus considerably shorter than inner; second pair not extending nearly so far backward as first or third; third uropods with rami flattened, lanceolate, over twice the length of the peduncle, margins of each with short spines and sete. Telson deeply cleft. Length 5 mm. Distribution: Woods Hole, Massachusetts ; Long Island Sound. Dredged at depths of 6 to 25 fathoms. According to Holmes: “The body and coxal plates in the living specimens were marked with blue or purplish pigment spots. . . . . Sometimes the blue or purplish color of these spots is replaced by a reddish brown, and in some specimens neither kind of spots occurs.” PONTOGENEIID. Body compressed. Rostrum not prominent. First antennz with peduncle not elongate, accessory flagellum usually wanting, never more than uniarticulate, Mouth parts normal. No. 26.] ARTHROSTRACA OF CONNECTICUT. gI Gnathopods with propodus not powerful, subchelate. Third uropods with rami subequal, of moderate size. Telson deeply cleft. Pontogeneia Boeck. Body slender, with none of the segments produced dorsally. Antenne slender and elongated, with the first pair a little shorter than the second and without an accessory flagellum; in the males, peduncles with calceoli. Gnathopods subequal, feeble; carpus considerably elongated and scarcely ‘expanded below; propodus narrow, with palm shorter than hind margin. Terminal uropods with peduncle short, rami subequal and lanceolate. Telson unarmed and deeply cleft. Pontogeneia inermis (Kr6yer). 1838. ee ? ae Gs y OC yr SS s) ZY Fig. 59. Ptilanthura tenuis. First antennz in the female shorter than second pair with a very short flagellum consisting of a small basal segment and a minute terminal one tipped with a few sete; first joint of peduncle long; second and third subequal and slightly longer than first. In the male first pair of antennz as long as head and first two segments of thorax together ; first segment large but not longer than second, which is also longer than the third; flagellum with first joint one-third as long as second joint of peduncle, 202 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. second joint of flagellum twice as long as first and bearing at distal end a fringe of long slender sete; eighteen to twenty suc- ceeding joints similar to second one. Mandibles and maxillipeds with uniarticulate palps. First six thoracic segments subequal in length; seventh seg- ment but little over half as long as preceding ones but broader behind than any of them. First pair of legs with carpus nearly equilaterally triangular, propodus moderately thickened, and dactyl strong and tipped with a strong spine, carpus and pro- podus with short sete on palmar margins. Succeeding pairs of legs slender and of subequal size. First five segments of abdomen consolidated along dorsal line but distinct laterally, subequal in length and each one twice as long as sixth joint. Telson long and narrow with rounded apex. Uropods with peduncle half as long as telson; inner ramus lamellar, triangular-ovate and extending as far as the telson; outer or superior ramus narrowly semiovate, extending to end of peduncle, somewhat triangular in shape, with acute apex. Color brownish, more or less mottled above, lighter beneath. Length 11 mm.; females about one-third smaller. This species occurs from the surface to 19 fathoms and has been taken from muddy bottoms; in sand, mud, and stones; at low water, in sand. Distribution: Grand Manan; Bay of Fundy; Casco Bay, Maine; Vineyard Sound; off Block Island; off Watch Hill, Rhode Island; Long Island Sound; Noank Harbor, Connecticut. The species is rare on this coast. CIROLANID. Body more or less semicylindrical in form. Coxal plates well defined except on the first segment. Head not produced medially. Abdomen usually composed of six distinct segments. Eyes not very large, lateral. Antenne very unequal in length, the first pair being very small, the second pair long, slender, and multiarticulate. Mandibles with cutting part long, more or less trifid; molar tubercle elongate, triangular. Maxillipeds well developed with margins of palp furnished with many sete but not with hooks. Legs ambulatory, although the first three pairs may also serve for prehension. No. 26.] ARTHROSTRACA OF CONNECTICUT. 203 Pleopods well developed, adapted for swimming and respira- tion. Second pair of pleopods in the male with a stylet inside the inner plate. Uropods lateral, and forming with the well developed terminal segment of the abdomen a caudal fan. Cirolana concharum ( oe Fic. 60. Cirolana scant 1874. Conilera concharum, Harger, Rep. U. S. Com. Fish. for 1871-2, p. 572. 1880. Ctrolana concharum, Harger, Rep. U. S. Com. Fish. for 1878-9, p. 378, pls. 9 and 10, figs. 58-63. Body three times as long as broad. Head quadrate, wider than long, anterior margin rounded, embraced at the sides by first thoracic segment. Eyes small, triangular and with angles rounded. First antennz robust, arising immediately beside each other; first and second segments subequal, each one-half as long as third joint; flagellum robust, tapering, consisting of about fifteen joints. Second antenne longer and more slender than first pair, not in contact with each other at origin; first and second joints short and subequal; third and fourth subequal and each as long as two preceding together ; fifth joint a little longer than fourth; flagellum composed of about sixteen joints. Mandibles robust, palp slender and triarticulate, with the second segment the longest and setose on inner margin beyond the middle, last segment slender and curved. Maxillipeds elongated and almost pediform but flattened; palp five-jointed with last four joints flat, broad, and densely setose. 204 CONNECTICUT GEOL. AND NAT, HIST. SURVEY. [ Bull. Second and third thoracic segments subequal in length and slightly shorter than the rest which are also subequal. Coxal plates distinctly separated from their respective segments on all but first segment. First pair of legs short and stout and well armed with spines and sete; ischium nearly triangular with upper margin much produced distally and setose; carpus short and small; propodus robust, somewhat curved; dactyl strong and short. Second and third pairs resembling first but with longer carpus. Fourth pair of legs short like the preceding but resembling the following except in size, provided abundantly with fascicles of sete; propodus straight and much narrower than carpus; fifth and sixth pairs of limbs increasing in size; last pair somewhat smaller. Abdomen slightly narrower than thorax, all six segments distinct ; fifth segment longer dorsally but shorter laterally than the preceding segments. Telson triangular, with setose apex truncated and notched at tip. Uropods extending only a little beyond the end of telson, provided with abundant long setz; rami of equal length, but outer one only about one-third as wide as inner one which has a notch on outer margin near posterior end; inner angle of peduncle produced and extending about two- thirds the length of the telson. Length of large specimens 32 mm., average length 22 mm. This species is found from the surface to depths of 18 fathoms, on muddy and sandy bottoms. It has been reported from Charleston, South Carolina; Curri- tuck, North Carolina; Long Island Sound; Block Island; off Fishers Island; Vineyard Sound; Woods Hole, Massachusetts. According to the Woods Hole Survey, it is sometimes taken in large numbers in winter from dead fish; and at Woods Hole has been known to block up the cocks of the water supply of the fish hatchery. fEGIDA. Body more or less broad and depressed, dorsal surface evenly vaulted and very smooth. Head comparatively small, broader than long, front not produced above bases of antennz. Eyes, when present, large. No. 26.] ARTHROSTRACA OF CONNECTICUT. 205 Antenne directed laterally; first pair shorter than second pair and originating close together; both pairs with distinct multiarticulate flagella. Mouth parts adapted for piercing and tearing; first maxillze with only a single lobe which is tipped with short spines. Second maxilla armed with recurved teeth, as is also the terminal joint of palp of maxilliped. Thoracic segments with coxal plates defined distinctly except on the first. First three legs short and thick, prehensile; last four more slender and ambulatory. Abdomen composed of six well defined segments, the last one large, scutiform and ciliated on hind margin. Uropods attached laterally beneath the terminal segment. Pleopods adapted for swimming and respiration. Parasitic, usually attached to the skin of fishes. f£ga psora (Linnzus). GN (ERE Ce Fic. 61 Afga psora. 1880. AEga psora, Harger, Rep. U. S. Com. Fish. for 1878, p. 384, pl. 10, fig. 64. 206 CONNECTICUT GEOL, AND NAT. HIST. SURVEY. [Bull. 1899. AZga psora, G. O. Sars. Crust. Norway, vol. 2, P- 59 pl. 24. 1905. ga psora, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 168. The following description is abbreviated from Harger's. I have not personally seen this species, Body oval, broadest at fourth and fifth thoracic segments where the breadth is about half the length; dorsal surface mod- erately convex and smooth except for minute and _ scattered punctations, which occur also on the legs, first antennz, uropods and pleopods. Head transverse and subtriangular, salient in front between the bases of the first antenne. Eyes very large and reniform covering nearly all the upper surface of the head. First antennze when bent backward attaining anterior margin of first thoracic segment; first two segments large and flattened ; third joint cylindrical; flagellum tapering, made up of about a dozen segments. Second antennz when reflexed extending beyond first thoracic segment; first two segments short and com- pressed; third somewhat longer; fourth and fifth longer and nearly cylindrical, followed by a tapering flagellum which is about as long as peduncle and composed of fifteen to twenty segments. First thoracic segment at anterior margin scarcely broader than head, expanding rapidly backward, excavated in front some- what for the accommodation of the eyes. Second, third, and fourth segments each a little shorter than first; fifth and sixth somewhat longer; seventh shorter than sixth. Coxal plates dis- tinctly demarcated from segments except the first one; those of second, third, and fourth segments rounded behind but those of succeeding segments becoming acute and extending backwards. First three pairs of legs short and armed with strong, hooked dactyls ; fourth to seventh legs of different form, slender; seventh pair only slightly developed in young but never quite as large as sixth which is the largest. Abdomen scarcely narrower than last thoracic segment and scarcely tapering to the fifth segment. Last segment triangular, with sides but little dilated and pointed at the tip. Uropods scarcely exceeding the abdomen; peduncle with inner angle long and spiniform, extending whole length of inner margin of inner ramus and ciliated toward tip; rami flattened, outer one elongate No. 26.] ARTHROSTRACA OF CONNECTICUT. 207 ovate, obtuse; inner with margin straight and outer margin curved and emarginate near the tip. Both rami and posterior portion of telson ciliated. Length 50 mm. Distribution: between delta of the Mississippi and Cedar Keys, Florida; off Marthas Vineyard; Fishers Island Sound; - Gulf of Maine; Gloucester, Massachusetts ; Nova Scotia; Labra- dor; Newfoundland; Gulf of St. Lawrence; Greenland; Hudson Bay; Ireland; Iceland; North Sea; in the German Sea; Spitz- bergen. This species is parasitic on skates, cod, and halibut. CYMOTHOIDA. Antenne strongly reduced and without clear distinction be- tween peduncle and flagellum. Mandibles with palp. First maxille with a single lobe con- sisting of a single joint furnished with four spines at the tip. Second maxillz bilobed at the tip and provided with numerous spines. Maxillipeds with two-jointed palp, the terminal joint of which is furnished with hooks. Coxal plates distinct on all the segments except the first. Legs all prehensile, terminating in strong hooked dactyls. Telson and uropods usually not ciliated. Parasitic in habit. ZEgathoa oculata (Say). 1818. Cymothoa oculata, Say, Jour. Acad. Nat. Sci. Phila., vol. 1, p. 398. 1880. gathoa loliginea, Harger, Rep. U. S. Com. Fish. for 1878, p. 393, pl. 10, fig. 66. Body elongate oval in outline, nearly four times as long as broad, slightly dilated just posterior to the middle. Head broadly rounded in front, as broad as long, and with posterior margin produced in three equal shallow lobes. Eyes large, compound, covering nearly half the area of head above, situated on postero- lateral angles of head. First antennz as long as head, composed of eight segments and separated at base; first segment short and stout; succeeding two a little longer but scarcely distinguishable from the five 208 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. segments of the flagellum which decrease in size distally. Second antenna composed of about ten joints, more slender than the first pair which they surpass in length; first two segments broader than the succeeding three, which are larger than the five joints of the flagellum. Fic. 62. Aigathoa oculata. First thoracic segment shorter than head but longer than segments two to six which are subequal in length; seventh seg- ment one-third shorter than the sixth; fifth and sixth joints the broadest. Coxal plates distinct on all the segments except the first and as long as their respective segments. Legs differing but slightly from each other; first pair the shortest; last four pairs weaker than the preceding; seventh pair the longest. Abdomen a little longer than thorax, becoming’ slightly narrower posteriorly. Telson as broad at insertion of uropods as third segment, and rounded behind. Uropods longer than telson; outer ramus narrow, longer than inner one, with nearly parallel sides and obliquely truncated tip; inner ramus rhom- boidal; peduncle with inner distal angle acute and only slightly produced; uropods and telson setose on posterior margins. Color in alcohol, yellowish with minute black specks which are most abundant on the abdomen. Eyes black, conspicuous. Length 13 mm. No. 26.] ARTHROSTRACA OF CONNECTICUT, 209 Distribution: St. Thomas, West Indies; Crisfield, Maryland; St. Johns River, Florida; Fort Macon, North Carolina; Savin Rock, near New Haven, Connecticut. The species is parasitic; one specimen was obtained from the mouth of a squid by S. F. Clark in 1874 at Savin Rock; other specimens were taken from young mullet at Fort Macon, North Carolina. Livoneca ovalis (Say). Fic. 63. Livoneca ovalis. 1818. Cymothoa ovalis, Say, Jour. Acad. Nat. Sci. Phila., vol. I, p. 394. 1874. Livoneca ovalis, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 572, pl. 6, fig. 29. 1880. Livoneca ovalis, Harger, ibid., for 1878, p. 395, pl. II, fig. 67. I have never met with this species myself. The following is from Mr. O. Harger’s description. Body broad, oval, usually oblique and with the sides of un- equal length; dorsal surface moderately convex. Head small, rounded in front, trilobed behind, the middle lobe much the largest, the two lateral lobes extending beyond the eyes which are inconspicuous, small, and broadly separated, 14 210 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. First antennze widely separated at the base, with the first jvint short and stout; second longer and tapering; third about as long as first; flagellum longer than peduncle, tapering, five-jointed. Second antennz as long as first pair; first two joints short and stout; the next three joints more slender; flagellum of three or four joints. First thoracic segment longest; next three a little shorter and equal; fifth and sixth still shorter; and seventh the shortest. Coxal plates narrow and obtusely pointed behind, but not ex- tending beyond the posterior angle of their respective segments except in the last two. First pair of legs short and stout; suc-, ceeding legs increasing in length posteriorly. Abdomen tapering rapidly at the sides; first five segments subequal in length; last segment as long as five preceding seg- ments, flat and broadly rounded behind. Uropods surpassing telson, with basal segment as long as rami and only slightly produced at inner angle; outer ramus linear oblong, rounded at end, inner ramus shorter and broader, oblique at the tip. Length 17-22 mm., breadth 10-12 mm. Distribution: Mobile, Alabama; Biloxi, Mississippi; Florida; Charleston, South Carolina; Virginia; Baltimore, Maryland; New York; Long Island; New Haven, Thimble Islands, Connecticut ; Woods Hole, Massachusetts; Vineyard Sound. ; This species is parasitic on the blue fish, saw fish, scup, sea trout, sun fish, etc. It is attached usually to the gills and roof of the mouth. LIMNORIID. Body subdepressed and capable of being rolled into a ball. Head short and very convex. Antenne small, subequal in size. Mouth parts normal, adapted for biting. Coxal plates behind the first segment of thorax distinct and laminar. Legs of uniform structure, ambulatory in function. Abdomen composed of six well defined segments, the last of which is very large and shield-shaped. Uropods comparatively small, lateral; rami not lamelliform. No. 26.] ARTHROSTRACA OF CONNECTICUT. 211 Limnoria lignorum (Rathke). Fic. 64. Limnoria lignorum. 1841. Limnorta terebrans, Gould, Invert. Mass., pp. 338, 354. 1874. Limnoria lignorum, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 571, pl. 6, fig. 25. 1880. Limnoria lignorum, Harger, ibid., for 1878, p. 373. 1899. Limnoria lignorum, G. O. Sars, Crust Norway, vol. 2, p. 76, pl. 31. Body three times as long as wide, oblong-ovate in form, tapering somewhat in front. Head nearly globular, partly covered above by first segment of thorax which is considerably longer than the subequal succeeding ones. Coxal plates distinctly sepa- rated on all the segments except the first. Eyes lateral, small, composed of only a few ocelli. First antenne stronger than second; flagellum extremely small, triarticulate, with a dense fascicle of sete. Second antennz with the flagellum about half the length of peduncle and made up of five joints of which the first is much the largest. First pair of legs larger than the succeeding ones but of the same form. Last pair more slender than the others. Dactyls of all the legs furnished with a large spine at the apex and a smaller one on the concave margin near the apex. Abdomen scarcely smaller than thorax, tapering but little; first four segments of equal length; fifth much longer; telson elliptical, broader than long, evenly rounded behind and fur- nished with sete. Uropods with peduncle strongly tuberculated 212 CONNECTICUT GEOL, AND NAT. ILIST. SURVEY. [ Bull. laterally and prolonged to an acute angle between the two rami, the outer one of which is short and unguiform and the inner one is sublinear, about the length of the peduncle and terminating in a dense tuft of sete. Color light grayish. Length 4.5 mm. Distribution: Coast of Great Britain; North Sea; Adriatic Sea; coast of Norway; Behring Island; Pacific Ocean; San Diego, California; from Florida to Halifax and the Gulf of St. Lawrence. It occurs above low-water mark but does not usually live far below that line. It has, however, been found by Professor Verrill at a depth of 10 fathoms in Casco Bay and has been dredged at a depth of 7% fathoms in Cape Cod Bay. This species may be recognized by its habits, being usually found burrowing in submerged timbers, which it may penetrate to the depth of half an inch. SPHAROMIDE. Body short, oval. Convex, capable of being rolled into a ball. Head transverse. First and second antennz multiarticulate, with evident dis- tinction into peduncle and flagellum. Mandibles with palps. Coxal plates united with their segments. Abdomen with the anterior segments short and fused; last segment large. Uropods lateral; outer ramus movable when present; inner ramus fixed. Sphzroma quadridentatum Say. 1818. Spheroma quadridentatum, Say, Jour. Acad. Nat. Sci. Phila., vol. 1, p. 400. 1874. Spharoma quadridentatum, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 560, pl. 5, fig. 21. 1880. Spharoma quadridentatum, Harger, ibid., for 1878, p. 368, pl. 9, fig. 53. Body ovate, twice as long as wide. Head twice as broad as long with a frontal border arising between the eyes and pro- i No. 26.] ARTHROSTRACA OF CONNECTICUT, 213 duced in a smal median point. Eyes small, rounded, widely separated, situated in the postero-lateral angles of the head. Fic. 65. Spheroma quadridentatum. First pair of antenne inserted on under side of head and fitting into groove when the animal contracts; first joint large; second joint small and conical; third joint longer than second and cylindrical in form; flagellum made up of about a dozen segments. Second antennz longer than first pair, likewise inserted on under side of head; first segment inconspicuous; second segment short; third twice as long as second; fourth and fifth subequal and each a little longer than the third; flagellum as long as peduncle and composed of about fifteen segments, Maxillipeds with basal segment short and somewhat tri- angular and with five-jointed palp. Segments of thorax subequal in length except the first which is longer than the rest ; coxal plates distinctly marked off from all segments except the first; postero-lateral angles drawn out into a narrow and subacute process which is more pronounced in the first four segments. Legs weak, furnished with long sete, ambulatory; dactyl in each case short and robust and provided with stout curved spine 214 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. at the tip; first pair with carpus short and triangular and ischium and merus with long sete on upper margin; second and third pairs with longer carpus. Abdomen composed of two segments; the first one of which resembles the last thoracic segment but is marked at the sides by two depressions indicating sutures. Telson long and widely rounded posteriorly, rather strongly contracted laterally at inser- tion of uropods. Uropods extending beyond end of telson; inner ramus with smooth margins; outer margin subequal to the inner in length and width, with three or four wide serrations on outer margin. Color extremely variable, some individuals of a uniform slatey gray; many marked dorsally with a whitish, creamy, or pinkish patch margined with black. Length 8 mm. ‘Distribution: Florida; Georgia; Virginia; Beaufort, North Carolina; Great Egg Harbor, New Jersey ; Savin Rock, near New Haven, Stony Creek, Connecticut ; Provincetown, Massachusetts ; Vineyard Sound. It is found in abundance under stones or creeping about the branches of seaweeds from low-water mark nearly to high-water mark. When disturbed this species curls itself up into a ball with facility and drops to the bottom. By this habit of rolling itself into a ball it may be distinguished from all other marine Isopoda of the coast. IDOTHEOIDEA or VALI'IFERA. First thoracic legs not cheliform. Uropods lateral, situated ventrally and opening and closing like valves over the five pairs of branchial pleopods; and attached on the outer margins to the terminal abdominal segment. IDOTHEIDA. Body more or less depressed, with segments of thorax of uniform appearance. First pair of antenne with uniarticulate flagellum. Second antenne with flagellum uni-or multiarticulate. Mandibles without palp. No. 26.] ARTHROSTRACA OF CONNECTICUT. 215 Coxal plates sometimes distinct, sometimes fused with their segments. Legs rather strongly built, increasing in length posteriorly ; three anterior pairs sometimes strongly subcheliform. Abdomen with some or all its segments consolidated to form a large termina! plate. Uropods very large, lamelliform, valve- like. Chiridotea cceca (Say). Fic. 66. Chiridotea ceca, 1818. Jdotea ceca, Say, Jour. Acad. Nat. Sci. Phila., vol. 1, Pp. 424. 1841. Idotea cwca, Gould, Invert. Massachusetts, p. 337. 1880. Chiridotea ceca, Harger, Rept. U. S. Com. Fish. for 1878, p. 338, pl. 4, figs. 16-19. 1905. Chiridotea ceca, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 353: Body ovate, broad and short, tapering to acutely pointed extremity ; abdomen nearly one-half as long as whole body. Head only slightly excavated in front for the antenne, with a triangular process not extending beyond the line of the front margin; deeply notched also at antero-lateral angles. Eyes small, inconspicuous, round, situated at base of posterior lateral lobe of head. First antenne longer than peduncle of second pair; first joint very short and not dilated; second joint strongly clavate and . 216 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. longer than first; third and fourth joints equal in length and each about twice as long as first. Second antennz with first joint very short; second, third, and fourth joints subequal; fifth joint a little longer than the fourth; flagellum made up of five joints and exceeding in length the last two joints of the peduncle. Thoracic segments subequal in length and broader than its mid-dorsal length; first segment broadly excavated for head. Coxal plates distinctly marked off from their segments except the first pair; last four pairs produced behind into acutely pointed processes. First three pairs of legs subchelate, with propodus swollen and dactyl short and reflex; last four pairs of legs ambu- latory and similar in form and increasing in length to the sixth which is the largest; all the legs with abundant sete. Abdomen composed of four segments; first three quite short, broadening somewhat posteriorly. Telson acutely pointed with lateral sutures of at least one more coalesced segment; lateral margins near extremity denticulated, converging for their anterior half gradually, and then more rapidly to the apex. Opercular valves ciliated along postero-external margin, in two parts, the small terminal part representing the outer ramus of the uropods; inner ramus attached to peduncle on the external side. Its color in life is variable but usually dark grayish. There may be a mottling of light yellowish gray at the sides of the head and body. Length 12-15 mm. Distribution: Florida; New Haven, Connecticut ; Long Island Sound; Woods Hole, Provincetowfi, Nantucket, Nahant, Massa- chusetts; Vineyard Sound; Halifax, Nova Scotia. This species is common on sand beaches at many localities on the New England coast and Long Island Sound. It is usually found below high-tide mark or burrowing just beneath the sur- face throwing up a little ridge like a mole, and making a little mound at the end. It swims with ease. It is distinguished from the following species by its large size and shorter second antennze which are but little longer than the first pair. From other New England Isopoda it may be distinguished by the broad subcircu- lar thorax, the articulated flagellum of the second antenne, and a two-valved abdominal operculum. No. 26.] . ARTHROSTRACA OF CONNECTICUT. 217 Chiridotea tuftsii (Simpson). u Fic. 67. Chiridotea tuftsti, 1853. IJdotca tuftsii, Stimpson, Marine Invert. Grand Manan, P: 39. 1874. Idotea tuftsii, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 569. 1880. Chiridotea tuftsii, Harger, ibid., for 1878, p. 340, pl. 4, figs. 20-23. 1905. Chiridotea tuftsiit, Richardson, Bull. U. S. Nat. Mus., No. 54, Pp. 354- Body ovate, less than twice as long as wide. Head twice as wide as long, with the front deeply excavate between the antero- lateral angles, and produced in a small median point; lateral margins bilobed, the posterior lobe being produced laterally beyond the anterior one. Eyes small, round, more distinct than in the preceding species, situated just within the cleft on the lateral margin. First antenne with first joint large and dilated; second joint longer than first, and third longer than second; flagellum made up of a single segment as long as the last two joints of the pedun- cle together, setose ; shorter than the peduncle of second antenne. Second antenne with first segment short; second joint twice as long as the first; third joint a little shorter than the second; 218 CONNECTICUT GEOL. AND NAT. HIST. survey. [Bull. fourth joint as long as second; fifth joint as long as the two preceding together; flagellum of about a dozen segments and longer than peduncle. , First segment of thorax deeply excavate in front to accommo- date the head. Coxal plates distinctly marked off from their segments except the first pair, postero-lateral angles of last four acutely produced. First three pairs of legs subchelate; first pair a little shorter than second and third pairs but with much more robust propodus; fourth to seventh pairs ambulatory, less spiny but more setose than in preceding species. Abdomen composed of four distinct segments of which the last one is twice as long as wide and has lateral sutures indicat- ing a partly coalesced segment, setose at the acutely pointed tip. Color usually light reddish brown, speckled with darker, or marked with dark transverse patches or bands. Length 9 mm. Distribution: Halifax, Nova Scotia; Bay of Fundy; Eastport, Maine; Casco Bay; Gloucester Harbor, Massachusetts Bay; Long Island Sound; off New London, Connecticut. It is found to depths of 25 fathoms. It is also found on sandy shores similar to the preceding species, but is rather more rare. Its habits are essentially the same as those of C. ca@ca but it can be distinguished from that species by its smaller size and its much longer second antennze, which are about twice as long as the first pair, as well as by its more conspicuous eyes. Idothea metallica Bosc. 1874. Idotea robusta, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 569, pl. 5, fig. 24. 1880. Jdotea robusta, Harger, ibid., for 1878, p. 349, pl. 6, figs. 30-32. 1905. Idothea metallica, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 362. Body oblong-ovate about two and one-fourth times as long as wide; abdomen nearly one-half as long as whole body. Head wider than long, with front margin slightly excavate, slightly wider behind than in front. Eyes large and round, com- pound, and situated at the extreme lateral margin. No. 26.] ARTHROSTRACA OF CONNECTICUT. 219 First antenne extending to end of second joint of second antenne, with first and second joint not enlarged and subequal; third and fourth joints subequal and each somewhat longer than either of the preceding. Second antenne with first joint very short; second and third joints subequal; fifth joint a little longer than the fourth which in turn is longer than the third; flagellum composed of eight joints. Thoracic segments subequal ; first embracing the head slightly on either side; lateral portions of the segments curved outward and somewhat upward forming an angle with the portion of the segment to which it is adjacent. Coxal plates from the second to the seventh inclusive, extending entire length of each segment, and very large and wide, increasing in width to the seventh, and giving a serrated appearance to the sides of the thorax. Legs all more or less alike in character, robust, and with free margins of all the joints and lower margin of the propodus setose. Abdomen composed of two short segments and a long telson with indications at the sides of coalescence of another short seg- ment. Telson with sides nearly parallel beyond the middle and broadly truncate or even slightly emarginate behind. Basal plate of operculum elongated and with parallel sides; terminal plate less than one-fourth as long and tapering slightly. Length of male 28 mm.; of female 22 mm. Distribution: Patagonia; New South Wales; Borneo; be- tween Montevideo and Straits of Magellan; southwestern Ire- land; Mediterranean; Florida Keys; North Carolina; off Mary- land; Chesapeake Bay; south shore of Long Island; Vineyard Sotind; Woods Hole, Massachusetts; Newport, Rhode Island; off Marthas Vineyard; near Isles of Shoals; Halifax, Nova Scotia. This species is pelagic, it is found swimming free as well as among masses of floating seaweeds. It is easily distinguished from other species of the genus by the telson which is broadly truncate and not the least pointed. From other genera of the New England coast, Idothea is dis- tinguished by the abdomen of apparently four segments of which the first three are short and the third is united in the dorsal region to the large vaulted telson; by the conspicuous two-valved oper- 220 CONNECTICUT GEOL. AND NAT. Hist. suRvEY. [Bull. culum, and the several segments of the flagellum of the second antenne, Idothea baltica (Pallas). SW » ( ‘ us. -— Dog wy , Fic. 68. Jdothea baltica. SI 1841. Stencsoma irrorata, Gould, Invert. Mass., p. 338. 1853. Idotca irrorata, Stimpson, Smithson. Contrib. Knowl., vol. 6, p. 39. 1874. Idotea irrorata, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 569, pl. 5, fig. 23; also ibid., for 1878, p. 343, pl. 5, figs. 24-26. 1883. IJdotea marina, Miers, Jour. Linn. Soc. London, Zool., vol. 16, p. 25. 1899. Idothea baltica, G. O. Sars, Crust. Norway, vol. 2, p. 80, pl. 32. 1905. Idothea baltica, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 364. Body oblong-ovate, three times as long as wide; abdomen slightly more than one-third as long as whole body. Head wider than long, slightly excavated in front and narrowing behind. Eyes, large, round, conspicuous, compound, situated just anterior to the median transverse line of the head and at the extreme lateral margin. First pair of antennz with first joint equal in length to the second and not expanded; third and fourth joints slightly longer No. 26.] ARTHROSTRACA OF CONNECTICUT, 221 than either of the preceding ones; scarcely exceeding in length the first three joints of the second pair. Second antenne with first three joints rather short and subequal in length; fourth joint longer than third, and fifth still longer, being twice as long as the third; flagellum of about a dozen segments of which the first is by far the longest and a little longer than the peduncle. Thoracic segments about equal in length. Coxal plates dis- tinct from their segments and forming a nearly even curved out- line, the segments being marked by incisions instead of serrations as in the other species. Legs more or less alike in structure and increasing in length posteriorly ; the first pair much stouter than the succeeding ones. Abdomen of two short segments followed by a long one which shows indications of coalescence of a third short segment, lateral angles of first two abdominal segments acute. Telson with lateral margins slightly convex and with apical margin produced in middle to an acute point which extends some distance beyond the lateral angles. Operculum with peduncle three times as long as the terminal ramus which is broadly truncate at the apex. Color varying greatly; frequently nearly uniform light or dark green, or brownish with blackish punctations. Females usually darker than the males which often have a median dorsal stripe. Length of males 30 to 38 mm.; of females 20 mm. Distribution: Java; Red Sea; New Zealand; Scandinavian coast; Baltic Sea; west coast of Europe to Great Britain; Medi- terranean; Caspian, and Black Seas; Bermuda; Barbadoes; Rio Janeiro; North Carolina north to Nova Scotia and the Gulf of St. Lawrence. Within Connecticut the species has’ been collected at New Haven, Stony Creek, Lyme, Noank, and off Stonington. From Cape Cod southward the species is abundant, but towards the north it is replaced by I. phosphorea. The species occurs on the surface, on floating seaweeds, some- times far from land. More commonly it is found among sea- weeds along the rocky shores of bays or sounds, and among the rocks at low water. In the Woods Hole Survey it was occasion- ally brought up in the dredge while operating at depths as great as 13% fathoms; but the specimens may have been taken in these cases near the surface. ‘ 222 CONNECTICUT GEOL. AND NAT. Hist. suRvEY. [Bull. Idothea phosphorea (Harger). 1874. Idothea phosphorea, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 569. 1880. Idothea phosphorea, Harger, ibid., for 1878, p. 347, pl. 5, figs. 27-29. 1905. Idothea phosphorea, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 367. Body oblong-ovate, slightly more than three times as long as wide; length of abdomen equal to greatest width of body. Head broader than long, with anterior margin straight on either side of a very slight median excavation. Eyes moderately large, round, compound and placed just in front of the median transverse line of the head at the extreme lateral margin. First antennz with first joint but little wider than second one, each of which is subequal in length to the third joint; fourth: - joint a little longer than any one of the preceding; extending to end of third peduncular joint of second pair. Second antennz with first joint inconspicuous and second and third joints subequal in length; fifth joint longer than fourth which in turn is longer than the third; flagellum shorter than peduncle and made up of about a dozen segments. Thoracic segments subequal in length, except the first which is shorter in the mid-dorsal line. Coxal plates distinctly marked off from their respective segments, except in the case of the first segment, and cach one in turn occupying a larger part of the lateral margins and becoming wider posteriorly. Legs of more ‘ No. 26.] ARTHROSTRACA OF CONNECTICUT. 223 or less similar structure throughout and furnished with sete along inferior margin of merus, carpus, and propodus. Abdomen of two short, free segments and a long telson show- ing indications of a partial coalescence of a third short segment. Telson tapering to a pointed apex, lateral margins exhibiting an obtuse, rounded angle behind the middle so that the posterior part tapers more acutely than anterior part. Operculum with basal plate tapering toward the end and with triangular terminal ramus which is a little longer than broad. Color very varied, usually dark green or brownish with patches of yellow or whitish. In general the color is darker than in I. baltica. Length 25 mm. Distribution: coast of New England to Halifax, Nova Scotia, and the Gulf of St. Lawrence. This species is found in conditions similar to the preceding one but is a more northern form as it is comparatively rare south of Cape Cod while it is abundant in Casco Bay and the Bay of Fundy. It has been collected within the limits of Connecticut at, New Haven, Stony Creek, off Saybrook, and Noank Harbor. It is readily distinguished from the other species of the same genus by the pointed telson. Edotea triloba (Say). 1818. Idotea triloba, Say, Jour. Acad. Nat. Sci. Phila., vol. I, p. 425. 1874. Epelys trilobus, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 571, pl. 6, fig. 28. 1880. Epelys trilobus, Harger, ibid., for 1878, p. 358, pl. 7, fig. 42-43. 1905. Edetea triloba, Richardson, Bull. U. S. Nat. Mus., No. 54, p: 396. Body ovate, nearly two and one-half times as long as wide; abdomen less than one-third as long as whole body. Head pro- duced slightly in front with two conspicuous tubercles very close together on either side of middle line, situated on front margin; antero-lateral angles of head produced in rounded lobes upon which the prominent eyes are placed. 224 CONNECTICUT GEOL, AND NAT, IlIST., SURVEY. [ Bull. First pair of antenna longer than the second pair; first and second joints equal in length; third joint twice as long as second; fourth joint about two-thirds as long as preceding. Second antenna reaching only to middle of fourth joint of first pair; shorter than head; fourth joint one and a half times as long as third which is subequal in length to each of the first two joints; fifth joint a little longer than the fourth; flagellum minute, com- posed of a single joint which is about one-third as long as the fifth joint. fk a Fic. 70. Edotea triloba, Third and fourth joints of thorax longer than any of the others and also the widest. Coxal plates of none of the segments distinctly separated; their lateral margins, especially in front, almost straight. Dorsal side of body characterized by two longi- tudinal depressions which divide it into a middle lobe and two lateral ones which bear each a rounded tubercle. Legs prehensile and slender with dactyls which are almost acicular; first pair by far the shortest. Abdomen composed of a single segment with slight incisions near the base indicating another segment partly coalesced; telson with a large rounded prominence situated in the median line at No. 26.] ARTHROSTRACA OF CONNECTICUT, 225 the base, followed by a depression so that in a lateral view the abdomen is seen to be in the form of two elevations separated by a deep depression; apex of telson also separated from second elevation by another depression; sides converging rapidly below the middle to a narrow, pointed apex. Color uniform, dull, usually obscured by adhering particles of dirt. Length 7 mm. Distribution: Great Egg Harbor, New Jersey; Staten Island; Savin Rock, near New Haven, Noank Harbor, Connecticut; Watch Hill, Rhode Island; Vineyard Sound; Provincetown, Gloucester, Massachusetts; Quahog Bay, Casco Bay, Maine. The species occurs among eel-grass, on piles, and in sheltered places among decaying vegetation and mud on the bottom, from the surface to 3 feet in depth. It is usually covered with adher- ing dirt.. It may be recognized among the native Isopods by the trilobed character of the back, the abdomen of a single segment, and the second antenne with only a rudimentary flagellum. Edotea montosa (Stimpson). 1853. Idotea montosa, Stimpson, Smithson. Contrib. Knowl., vol. 6, p. 40. 1874. Epelys montosus, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 571. 1880. Epelys montosus, Harger, ibid., for 1878, p. 359, pl. 8, figs. 44-47. 1905. Edotea montosa, Richardson, Bull. U. S. Nat. Mus., No. 54, p- 397- Body ovate, a little more than twice as long as wide; abdomen slightly more than one-third as long as entire body. Head with front margin triangularly produced and with two low tubercles situated on the anterior margin. Eyes placed on the antero- lateral lobes which are rounded. First antennz with first and second joints equal in length, third joint twice as long as first, fourth joint slightly more than half as long as third. Second pair of antennz extending not quite as far as third joint of first pair, with first three joints subequal and fourth and fifth successively longer; flagellum com- 15 226 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. posed of a single joint one-half as long as fourth joint of peduncle. Maxillipeds with triarticulate palp. ®O ) ca =) [Yokes x = SY \ Lf £ Eo Y S. Z \G CT See & J Gay | \ Q Lea ey ji) & C/ AY Fic. 71. Edotea montosa. Third and fourth thoracic segments longer and wider than any of the others. Epimera firmly united with their respective segments but demarcated by a slight linear depression, with rounded margins. Legs all prehensile; first pair much shorter than the other six. Abdomen composed of a single segment which represents two coalesced as shown by lateral incisions at the base of the abdomen and a slight depression extending inwards a short distance on either side; dorsal surface with a depression just behind the level of the lateral incisions and another one near the extremity sepa- rating off the small terminal point from the large median eleva- tion; sides of abdomen converging to a triangular apex. Length 9 mm. Distribution: Block Island Sound; Long Island Sound; Vine- yard Sound; Eastport, Maine; Georges Bank; Stellwagens Bank; Casco Bay; Bay of Fundy; Halifax, Nova Scotia; Grand Manan. The species occurs in mud and fine sand at depths of from 8 ‘ No. 26.] ARTHROSTRACA OF CONNECTICUT. 227 to 25 fathoms, and is always concealed by an adhering layer of mud. It is distinguished from the preceding species by the more rounded lateral margins of the body, the different form of the abdomen, and the absence of tubercles on the lateral portions of the thoracic segments. Erichsonella attenuata (Harger). Fic. 72. Erichsonella attenuata, 1874. Erichsonia attenuata, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 570, pl. 6, fig. 27. 1880. Erichsonia attenuata, Harger, ibid., for 1878, p. 356, pls. 6 and 7, figs. 36 and 37. 1905. LErichsonella attenuata, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 400. Body narrow, elongate, about five times as long as. wide; abdomen one-fourth as long as entire body. Surface of body smooth throughout. Head wider than long with anterior margin slightly excavate between the prominent antero-lateral angles, with a prominent elevation between the eyes, which are small, compound, and situated half way between anterior and posterior margins of the head on the lateral margins. First pair of antenne with first joint large and dilated ; second joint a little shorter than the first and half as wide; third and fourth joints subequal in length and each one and a half times as long as the second; extending slightly beyond the second joint 228 CONNECTICUT GEOL. AND NAT, HIST. SURVEY. [ Bull. of the second antenna. Second antenne more than half as long as body with the peduncular joints increasing in length to the fourth; fifth joint a little shorter than fourth; flagellum made up of a single joint a little longer than fourth joint. First segment of thorax slightly shorter than any of the others except the seventh; second to fifth segments subequal in length; sixth joint, a little shorter than the preceding ones; third segment broadest. Coxal plates distinctly separated on all the segments including the first, placed in the first three segments on the lateral margin anterior to the middle, in the fourth segment at the middle, and in succeeding segments behind the middle; pro- ducing a somewhat angular appearance to the otherwise very even outline of the body. Legs ambulatory and furnished with bi-unguiculate dactyls. Abdomen composed of only a single segment; with a small lateral process on either side about one-third the distance from the base to posterior end; posterior to the lateral processes the sides are parallel for about one-half the distance and then con- verge to a rounded apex. Operculum with basal plate more than three times as long as broad, and terminal plate elongated and obtusely triangular. The color in life is usually uniform dark green, sometimes. with an obscure dorsal stripe of a lighter color. Length 15 nim. This species has been collected at Great Egg Harbor, New Jersey; and Noank, Connecticut. It is not a common species although it was abundant on eel-grass at the first mentioned locality in April, 1871. It may be distinguished from the other genera of isopoda of Connecticut by the flagellum of the second antenne which is clavate and from the following species by its slender form and regular outline. Erichsonella filiformis (Say). 1818. Stenosoma filiformis, Say, Jour. Acad. Nat. Sci. Phila., vol. I, p. 424. 1874. LErichsonia filiformis, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 570. - No. 26.] ARTHROSTRACA OF CONNECTICUT. 229 1880. Erichsonia filiformis, Harger, ibid., for 1878, p. 355, pl. 7, figs. 38-41. 1905. FErichsonella filiforimis, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 401. Fic 73. Erichsonella filiformis. Body oblong-ovate, about three and one-half times as long as wide; abdomen as long as greatest width of body. Head with front margin deeply excavate between the prominent antero- lateral angles; dorsal surface of head with a prominent, rounded elevation bearing two slender, rounded tubercles, one on each side of the middle line. Eyes large, round, compound, situated at about the middle of the head at the extreme lateral margins. First antennz with basal joint large and dilated; second and third joints subequal and only slightly shorter than first; fourth joint a little longer than third; extending to end of third joint of second antenne. Second antenne with first joint very short; second and third joints subequal in length and equal to the first two joints of the first antenne combined; fourth joint nearly twice as long’ as third; and fifth shorter than fourth; flagellum clavate, as long as fourth joint, extending when retracted about .-as far as hind margin of fifth thoracic segment. 230 CONNECTICUT GEOL. AND NAT. 11st. suRveY. [Bull. Thoracic segments, each with a smaller median tubercle near its posterior margin ; first two segments with lateral margins pro- duced in very acute processes, one on either side of each segment ; lateral parts of third and fourth segments produced on each side into two acute processes of which the anterior one is the larger; last three segments with anterior part of lateral margin acutely produced. Coxal plates distinct, that of first segment being acute and anterior in its position; that of the second being bilobed, the upper division concealing the smaller acute lower one; coxal plates of third and fourth segments acute but not very con- spicuous ; those of the last three segments also acute and attached to posterior part of segment. This condition of the coxal plates and lateral margins gives the appearance of fourteen teeth on each side of the thorax. Legs all more or less similar and terminated by a subchelate propodus and dactyl. Abdomen composed of a single segment which is produced on either side in an acute angular process about one-third the distance from the base to the apex ; lateral margins diverging very slightly behind the angular processes for one-third the length of the abdomen and then converging rapidly to a triangular apex which is rounded. Operculum a little more vaulted and shorter than in the preceding species; basal plate less than three times as long as wide, terminal plate triangular. Color usually dull, neutral tint without bright markings. Length 11 mm. Distribution: The Bahamas ; Florida; Great Egg Harbor, New Jersey ; Long Island Sound; Vineyard Sound; Nantucket Sound; Fishers Island Sound; Thimble Islands and Noank, Connecticut. It is usually found in tide-pools or among eel-grass and alge and in sand and gravel to a depth of 18 fathoms. The species may be distinguished by the clavate flagellum of the second antennz and the strongly serrated outline of the sides. ASELLOIDEA or ASELLOTA. First thoracic legs not cheliform; uropods terminal, biramous ; outer branch of pleopods never two-jointed ; pleopods exclusively branchial, generally covered by a thin opercular plate (the modi- fied first pair). No. 26.] ARTHROSTRACA OF CONNECTICUT. 231 Second pair of antenne elongate. Epimera very small or obsolete. Abdominal segments all fused together forming a broad, shield-like plate. Mouth parts normal; maxillipeds furnished with an epipod and five-pointed palp. ASELLIDA. Body broad, depressed. Head without rostrum. Caudal segment large, shield-like. Eyes small, lateral. Antenne with multiarticulate flagella; superior pair much smaller than inferior pair. Mouth parts normal. Pereiopods ambulatory, except the first pair which are sub- chelate. Pleopods, four pairs in female; the first very small, not oper- culiform; the three succeeding pairs biramous and lamelliform; the outer ramus of second pair forming an operculum. In male, five pairs of pleopods, an additional one between the first and second forming the copulatory organs. Uropods large, biramous, with rami styliform or lamellar. Asellus communis Say. 1818. Asellus communis, Say, Jour, Acad. Nat. Sci. Phila., vol. 1, p. 427. 1841. Asellus vulgaris, Gould, Invert. Mass., p. 337. 1905. Asellus communis, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 420. Body oblong-ovate, about three times as long as wide; thorax and abdomen of equal width. Head narrower in front than behind and with anterior margin excavate. Eyes small, round, compound, situated laterally half way between front and hind margins. First antennz extending to the middle of last joint of second pair; second joint longer than third which in turn is’ longer than the first; flagellum made up of about fourteen joints. Second antenne more than half as long as body; fifth joint of peduncle one and two-thirds as long as fourth joint which equals the length of the first three joints together; flagellum much longer than peduncle. 232 CONNECTICUT GEOL. AND NAT. Hist. suURvEY. — [Bull. Mandibles with triarticulate palp. Maxillipeds with five- jointed palp. First pair of legs subchelate; carpus very minute; propodus oblong, with hind margin bearing several stout spines at junction with palm; dactyl nearly as long as propodus and deeply serrated. Succeeding legs with numerous spines; merus prolonged on anterior margin and armed with a group of long spines. Coxal plates very small. Fic. 74. Asellus communis. Abdomen composed of two short segments which are visible only on the mid-dorsal line and a large terminal one which is nearly as long as it is wide and has the postero-lateral angles rounded and the posterior margin produced in a broad triangular process between the uropods. Uropods as long as last segment of abdomen; rami styliform, inner ramus as long as peduncle, outer one about two-thirds as long. Length 15 mm. Distribution: Potomac River ; Schuylkill River, Pennsylvania; Cincinnati, Ohio; Mississippi; Michigan; Illinois; Indiana; Massachusetts; Rhode Island; New Haven, Canaan, Berlin, Connecticut. No. 26.] ARTHROSTRACA OF CONNECTICUT. 233 This is a very abundant species, occurring everywhere in brooks and ponds, under stones, and crawling over the stems of water weeds. It is very tenacious of life; a single specimen survived in a vial containing a small amount of clean water for a space of three months, with nothing to feed on except possibly the cork of the vial which lay on its side for part of the time. This specimen, together with several others about 5 mm. in length, was brought to me by Mr. S. C. Ball who found them in water drawn from a faucet in New Haven in Igio. JANIRIDZ. General appearance like that of the Asellide but with the lateral margins of head always lamellarly expanded. Eyes, when present, subdorsal. First antenne sometimes well developed, with multiarticulate flagellum, sometimes very small and with rudimentary flagellum. Second antenne always longer than first pair, with peduncle of six segments and with small scale-like appendage external to the third joint. Mouth parts normal. Legs subequal in length, with dactyls bi- or tri-unguiculate ; first pair sometimes differing from others in being prehensile. First pair of pleopods in female in form of single, large oper- cular plate; in male constituting the median piece of the com- pound operculum, the lateral pieces of which are formed by the copulatory organs. Uropods biramous. Jera marina (Fabricius). 1853. J@ra copiosa, Stimpson, Smithson, Contrib. Knowl., vol. 6, p. 40, pl. 3, fig. 20. 1868. Jera albifrons, Bate and Westwood, Brit. Sess. Crust., vol. 2, p. 317. 1874. Je@ra copiosa, Harger, Rept. U. S. Com. Fish. for 1871-2, p. 571. 1880. Jera albifrons, Harger, ibid., for 1878, p. 315, pl. 1, figs, 4-8. 1899. Jera marina, G. O. Sars, Crust. Norway, vol. 2, p. 104, pl. 43. 234 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. (i SH WN gw 3 C} WYN WO \ / Ke % y Fic. 75. J@ra marina, 1905. J@ra marina, Richardson, Bull. U. S. Nat. Mus., No. 54) P- 450. Body oblong-ovate, about twice as long as wide; abdomen one-half as long as greatest body width. Head twice as wide as long, with front margin produced in middle in a large rounded lobe; lateral margins straight and sparsely setose, postero- lateral angles rounded, antero-lateral angles not greatly produced. Eyes small, oval, compound, situated dorsally near posterior margin of head. First antennz with first joint large and dilated; second joint much narrower and slightly shorter than first; succeeding joints each decreasing in length and width; flagellum of two joints; not extending to fourth segment of second antenne. Second antenne with first three joints short and subequal; fourth joint robust and as long as first three combined; fifth joint the longest ; No. 26.] ARTHROSTRACA OF CONNECTICUT. 235 flagellum composed of about eighteen segments and reaching as far as hind margin of fifth thoracic segment. First three thoracic segments subequal in length and longer than the last four which are also subequal in length, except the fifth which is shorter than the, preceding. Lateral margins sparsely setose and projecting so as to cover the basal joints of the legs but coxal plates not distinct, lateral margins of first three segments squarish, of fourth and fifth segments rounded, and of last two segments obtusely angulated behind. Legs all of similar form, ambulatory, but increasing in length behind. Abdomen composed of a single joint which is setose on the margin and rounded behind with a small median excavation for the reception of the uropods. Uropods scarcely projecting be- yond the general outline of abdomen, biramous, with short stumpy peduncle and outer ramus about one-half as large as inner. Color very variable, commonly dark, slaty gray with dots or small blotches of yellowish. Length, according to Harger, extremely variable, females frequently bearing eggs when less than half the length of speci- mens figured which is about 7 mm. The males are at least one- third smaller than the females. Distribution; North Sea; Baltic Sea; Greenland; Finland; Denmark ; Scotland; England; Bay of Fundy; Labrador; East- port, Casco Bay, Maine; Gloucester, Provincetown, Massachu- setts, Vineyard Sound; Noank Harbor, Stony Creek, New Haven, Connecticut. This species is quite active in its habits and is found crawling over rocks and barnacles, and especially beneath rocks and drift wood, often nearly up to high-water mark. It is sometimes found in the burrows of Limnoria. It has been noted by McMurrich to breed from the middle of June to the first week in September. It is distinguished readily from the other marine Isopoda of Connecticut by the short uropods, arising from a notch at the apex of the rounded abdomen and the multiarticulate flagellum of the second antenne. BOPYROIDEA or EPICARIDEA. First thoracic legs not cheliform; uropods terminal, but some- times pleopods and uropods are absent; when present pleopods 236 CONNECTICUT GEOL. AND NAT. Hist. suRvey. [Bull. are exclusively branchial and not covered by an operculum. Parasitic forms. These are the most degraded forms of Isopoda; in some instances the fully-grown female represents merely a simple sac. filled with ova, and without any trace of segmentation or of limbs, In all cases the male is much smaller than the adult female and is generally found clinging to the genital region of the female like a parasite. BOPYRID/E. Body of female distinctly segmented and somewhat asymmet- rical. Eyes, when present, dorsal. Both pairs of antenne rudimentary. Legs, seven pairs, sometimes obsolete on one side, all of same structure, short prehensile. Coxal plates obsolete or distinct. Marsupial plates five pairs; of which the first pair is made up of two segments. Abdomen more or less distinctly defined. Uropods, when present, simple, lanceolate. Male, symmetrical. Head rounded in front. Thoracic segments distinct. Legs similar, prehensile. Segments of abdo- men sometimes distinct, sometimes united. Parasitic on decapods. Stegophryxus hyptius Thompson. 1902. Stegophryxus hyptius, Thompson, Bull. U. S. Fish. Com., vol. 21, p. 53-56, pls. 9, ro. 1905. Stegophryxus hyptius, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 532. A species of Bopyrid which is parasitic on the gills of Pagurus longicarpus (hermit crab), collected at Woods Hole, Hadley Harbor, Naushon, Edgartown, Massachusetts, and War- wick, Rhode Island. Probopyrus pandalicola (Packard). 1881. Bopyrus palemoneticola, Packard, Zoology for High Schools and Colleges, p. 288. 1905. Probopyrus pandalicola, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 554. No. 26.] ARTHROSTRACA OF CONNECTICUT, 237 The following description is from Miss Richardson’s Mono- graph on the Isopods of North America. “Head deeply set in thorax; anterior margin straight ; poste- rior margin rounded. Eyes wanting. Ovarian bosses present on the first four segments of the thorax at the anterior part of the sub-lateral margin; epimera evident as narrow plates lateral to the ovarian bosses. The epimera occupy the entire lateral mar- gins on the last three segments. The segments of the abdomen are distinct. The terminal segment is broad, more or less bilobed. The pleopoda consist of five pairs of double-branched lamellar appendages, closely crowded together on the ventral side of the abdomen. “The five pairs of incubatory lamelle surround a large open area normally filled with eggs. The first pair have the terminal lobe of the distal segment large, well defined, and incurved. “All the legs have a high quadrangularly shaped expansion or carina on the basis. “ Male with all the segments of the thorax distinct, and with the lateral margins contiguous. First four segments of the abdomen well defined at the sides, but fused in the middle of the dorsal surface. The last two segments form a single large piece, the fused terminal segment being indicated only by a small median point on the posterior margin. The body is a little more than twice as long as wide. Eyes are present. The rudimentary pleopoda are pairs of small oval processes, one pair on each abdominal segment. The abdomen is about one and a half times as broad as long.” This species is parasitic on Palemonetes vulgaris (a prawn) and has been reported from New Hampshire to Florida; East Providence, Rhode Island; Acushnet River, Massachusetts ; Bald- win Ledge, Mississippi; Brooklyn, New York. ONISCOIDEA. Body more or less depressed, oval or oblong in form, in some cases capable of being rolled into a ball. Head generally small and more or less sunk into first segment of thorax, no true rostral projection. First antennz always of very small size, never composed of more than three segments, the last of these being often rudimen- 238 CONNECTICUT GEOL. AND NAT. HIST. sURVEY. [Bull. tary. Second antennz of normal structure and moderate length, seldom, exceeding half the length of the body. Mouth parts adapted for biting. Mandibles without palp. Maxillipeds not completely covering the other mouth parts and with terminal parts more or less reduced. Thorax composed of seven well defined quite similar segments, the lateral parts of which are generally expanded to thin, forni- cate plates. Abdomen composed of six well defined segments. Pleopods five pairs, which are respiratory in function; the inner plate being of very delicate spongey structure whereas the outer is more strongly chitinized and covers the inner like an operculum. .\ir cavities are sometimes present in this oper- culum. Uropods biramous, with rami uniarticulate. Oniscus asellus Linnzus. Fic. 76. Oniscus asellus. 1818. Oniscus affinis, Say, Jour. Acad. Nat. Sci. Phila., vol. I, p. 430. 1841. Oniscus asellus, Gould, Invert., Mass., P. 336. 1899. Oniscus asellus, Sars, Crust. Norway, vol. 2, p. 171, P. 75: 1905. Oniscus asellus, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 600. , No. 26.] ARTHROSTRACA OF CONNECTICUT. 239 1905. Oniscus asellus, Paulmier, Bull. N. Y. State Mus., No. gt, p. 180. Body oblong-ovate, about one and one-half times as long as wide. Head twice as wide as long, with frontal margin slightly convex, and pronounced antero-lateral lobes which are narrow and elongated and rounded anteriorly. Eyes large, compound, oval, situated at sides of head at base of antero-lateral lobes. First antenne very small and inconspicuous. Second pair extending when retracted to posterior margin of third thoracic segment, with first joint short; second and third subequal and each twice as long as the preceding; fourth joint nearly twice as long as third; and fifth joint one and a half times as long as fourth; flagellum composed of three joints and shorter than last peduncular joint. Thoracic segments of subequal length; first one with antero- lateral angles produced to embrace head, extending nearly to the extremity of the antero-lateral angle of head. Coxal plates not distinct but lateral margins of all the segments well expanded and straight, producing an even contour. Legs moderately slender, increasing in length posteriorly. Abdomen not abruptly contracted; all the segments distinct, the first two considerably shorter than the others and with their lateral margins completely concealed by the last thoracic seg- ment; lateral margins of third, fourth, and fifth segments ex- panded, and produced and curved posteriorly to continue the oval outline of the body, those of the fifth segment being produced backwards strongly as far as the extremity of the last segment. Terminal segment triangular with apex produced considerably and pointed and convex above. Uropods rather produced, with the inner ramus originating far in front of the outer; peduncle extending beyond the middle of last abdominal segment; inner ramus narrow, linear, reaching as far as apex of abdomen; outer ramus narrow lanceolate, extending beyond the apex. Color, dorsal portion of body dark brown; lateral margins of body and longitudinal rows of spots on either side at union of coxal plates and body segments, light yellow. Length 16 mm. Distribution; Greenland; Iceland; Sweden; Norway; Den- mark; Great Britain: France; Spain; Italy; Azores; also Woods 240 CONNECTICUT GEOL. AND NAT. ust. SURVEY. — [Bull. Hole, Salem, and Beverly, Massachusetts ; New Haven, Connecti- cut; Providence; Rhode Island; New York City, Schenectady, New York; Rock Island, Illinois; Maine; Pennsylvania. This species is found under dead logs, leaves, and stones and is common in hothouses. It may be recognized among the terrestrial Isopoda by the even, rounded contour of the front and the pronounced antero- lateral lobes of the head and the three joints of flagellum of second antenna, Philoscia vittata Say. Fic. 77. Philoscia vittata. 1818. Philoscia vittata, Say, Jour. Acad. Nat. Sci. Phila., vol. I, p. 429. | 1874. Philoscia vittata, Harger, Rept. U. 5. Com. Fish. for 1871-2, p. 569. 1880. Philoscia vittata, Harger, ibid., for 1878, p. 306, pl. 1, fig. 1. 1905. Philoscia vittata, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 605. Body oval, smooth, nearly three times as long as wide. Head wider than long, with anterior margin rounded and antero-lateral angles rounded and not produced to lobes. Eyes small, round, compound, situated in antero-lateral angles of head. No. 26.] ARTHROSTRACA OF CONNECTICUT. 241 Antennz minutely hirsute, especially on the flagellum, extend- ing to posterior margin of third thoracic segment; first segment short ; second twice as long as first; third segment as long as the second, clavate; fourth nearly twice as long as the third; fifth longer than fourth; flagellum composed of three nearly equal joints ; the terminal one of which is tapering. First thoracic segment longer than the succeeding ones which are subequal; anterior angles of first segment somewhat produced at the sides to embrace the posterior part of the head; second and third segments with their posterior angles less broadly rounded but not produced backward at all; fourth, fifth, and sixth seg- ments with posterior angles increasingly produced toward the posterior end and acute. Legs all ambulatory and increasing in size and length to the last pair. Abdomen abruptly narrower than the thorax, two-thirds as wide as the last thoracic segment; first two segments with lateral lamelle nearly concealed by the seventh segment of the thorax; lateral lamella of the three succeeding segments not large, acute. Telson acute but not prolonged behind and not extending beyond the end of the peduncle of the uropod which is broad. Uropods with rami originating at the same distance from the base; outer ramus narrowly lanceolate, tapering to the tip and exceeding by less than one-half its length the more slender, styliform inner ramus. Color, dull and somewhat variable, usually brownish with light lateral margins and narrow, median stripe separating the two wide, dark bands. Length 8 mm. Distribution: Great Egg Harbor, New Jersey; Freeport, Long Island; Salem and Barnstable, Massachusetts; Vineyard Sound; Stony Creek, Connecticut. This species is found under rubbish and stones on the shore below high-water mark. Say states that it is “ very common under stones, wood, etc., in moist situations.” Cylisticus convexus (DeGeer). 1899. Cylisticus convexus, G. O. Sars, Crust. Norway, vol. 2, p. 186, pl. 81. 16 242 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 1908. Cylisticus convexus, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 609. 1905. Cylisticus convexus, Paulmier, Bull. N. Y. State Mus., No. 91, p. 181. Fic. 78. Cylisticus convexus. Body oblong-ovate, a little more than twice as long as wide, dorsal surface strongly convex; able to contract into a ball like an armadillo. Head twice as broad as long with the antero-lateral angles produced in large and rounded lobes; median lobe small and triangular and with acute apex. Eyes small and compound, situated at the bases of the antero-lateral lobes. First pair of antennz inconspicuous, very small. Second pair long and slender with flagellum composed of two sub- equal joints; peduncular joints -increasing in length distally. Thoracic segments subequal in length; large coxal plates not distinct from their segments ; those of first segment expanded to embrace the head, extending to base of antero-lateral lobes as well as posteriorly in acute processes ; lateral margins straight. Legs moderate, increasing in size posteriorly. Abdomen with six distinct segments not abruptly contracted ; first two with lateral margins covered by last thoracic segment; third, fourth, and fifth with lateral lamelle prominent and curved posteriorly to continue the even outline of the body. Telson tri- angular, conically produced. Uropods considerably produced beyond general outline of body, with peduncle extending a little beyond the middle of apical process of telson; inner ramus origi- No. 26.] ARTHROSTRACA OF CONNECTICUT. 243 nating far in front of outer one and extending as far as telson while outer ramus extends more than half its length beyond the abdomen. Color light brown with longitudinal row of yellow spots on either side marking union of coxal plates and segments; also with markings of yellow wavy lines between the median line and the longitudinal rows of yellow spots. Length 12.5 mm. Distribution: Sweden; Norway; Denmark; Germany; British Isles ; Holland; Belgium; France; and Turkey; also New Mexico; Michigan ; Lake Erie, Syracuse, Norwich, New York City, New York; Ohio; Rock Island, Illinois; Washington, District of Columbia; New Haven, Connecticut. This species is found in woods, under logs, along roads, under stones, in woodsheds, usually in moderately dry places. It may be distinguished from other terrestrial forms by the great convexity of the body and its ability to roll up into a ball. Armadillidium is the only other terrestrial form capable of roll- ing into a ball but with this there can be no confusion because of the pointed telson and prominent uropods of Cylisticus. Porcellio spinicornis Say. Fic. 79. Porcellio spinicorms, 1818. Porcellio spinicornis, Say, Jour. Acad. Nat. Sci. Phila., vol. I, p. 431. 244 CONNECTICUT GEOL. AND NAT. HIST. suRvEY. — [Bull. 1899. Porcellio pictus, G. O. Sars, Crust. Norway, vol. 2, p. 177, pl. 78, fig. 1. 1902. Porcellio spinicornis, Stoller, 54th Rept. N. Y. State Mus., p. 213. 1905. Porcellio spinicornis, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 619. 1905. Porcellio spinicornis, Paulmier, Bull. N. Y. State Mus., No. 91, p. Body oblong-oval, considerably depressed ; surface rough, with less dense tubercles than in P. scaber. Head. with very large lateral lobes which are slightly curved outwards; frontal lobe less prominent, broadly rounded. Eyes large, compound, situated at the base of the lateral lobes. First pair of antennz inconspicuous. Second pair rather slender and nearly one-half as long as body; second and third peduncular joints with a carina on the outside which is pro- duced to a dentiform projection; flagellum not as long as last joint of peduncle, composed of two joints of which the proximal is nearly twice as long as the distal one. Coxal plates of thorax well developed with posterior corner acuminate. Last pair of legs more strongly built in the male than female, with carpus dilated. Abdomen scarcely one-fourth as long as body; third to fifth coxal plates prominent and recurved. Telson strongly produced, one and a half times as long as broad at the base, terminal part acute. Opercular plates of only the first and second segments of abdomen provided with air cavities. Uropods with rather broad outer ramus. Color, yellowish gray, variegated with dark brown patches, generally arranged in five long series. Length 13 mm, Distribution ; Sweden; Norway ; Denmark; Russia ; Germany ; France; Great Britain; Hungary; also New York City, Niagara | Falls, New York; Goshen, New Haven, Connecticut. The species occurs in crevices of rocks and on shady lime- stone ledges (Stoller) and also in damp cellars, ete. It is distinguished from the two following species by the spotted body and yellow color, and the flagellum of the second an- tennz, the first joint of which is a little longer than the second. No. 26.] ARTHROSTRACA OF CONNECTICUT. 245 Porcellio scaber Latreille. Fic. 80. Porcellio scaber. 1818. Porcellio nigra, Say, Jour. Acad. Nat. Sci. Phila., vol. I, p. 432. . 1853. Porcellio gemmulatus, Dana, U. S. Expl. Exped., vol. 14, p. 725, pl. 47. 1899. Porcellio scaber, G. O. Sars, Crust. Norway, vol. 2, P- 176, pl. TF: 1902. Porcellio scaber, Stoller, 54th Rept. N. Y. State Mus., Pu2t3. 1905. Porcellio scaber, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 621. 1905. Porcellio scaber, Paulmier, Bull. N. Y. State Mus., No. gt, p. 183. Body oblong-oval, twice as long as broad; dorsal surface con- vex and very rough with tubercles. Head with lateral lobes large and rounded; frontal lobe less prominent and obtusely triangular. Eyes large and compound, placed at the base of the lateral lobes. Second pair of antennz slender and scarcely one-half as long as body; flagellum subequal in length to the last peduncular joint and made up of two subequal joints. Coxal plates of thorax moderate in size, with their posterior corners acutely produced. Last pair of legs differing very little in the two sexes. Abdomen at least one-fourth as long as body; coxal plates of third to fifth segments strongly recurved. Opercular plates of 246 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. only first and second segments provided with air cavities. Telson rather strongly produced and terminating in an acute point. Uro- pods longer than terminal segment, outer ramus broadly lanceo- late and comparatively longer in male than female. Color, uniform gray black, sometimes variegated with irregular dark spots. Length 10 mm. Disrtibution; world wide. British Columbia; Iceland; Cape of Good Hope; Key West, Florida; also West Haven and New Haven, Connecticut. The species is found under logs and bark in generally dry places, also under dead leaves and stumps and under boards, in greenhouses. It is distinguished from the other species of the genus by the unspotted body. Porcellio rathkei Brandt. ass i ; Z | Ne Fic 81. Porcellio rathkei, 1833. Porcellio rathkei, Brandt, Bull. soc. imp. Nat. Moscou. vol. 6, p. 177. 1899. Porcellio rathkei, G. O. Sars, Crust. Norway, vol. 2, p. 180, pl. 70, fig. 1. 1905. FPorcellio rathkei, Richardson, Bull. U. S. Nat. Mus., No. 54, p. 622. , No. 26.] ARTHROSTRACA OF CONNECTICUT. 247 1905. Porcellio rathkei, Paulmier, Bull. N. Y. State Mus., No. 1, p. 183. Body oval, somewhat broader in female than male; dorsal surface rather convex and slightly tuberculated. Head with lateral lobes well developed, rounded; frontal lobe short, obtusely triangular. Second pair of antennz rather slender, nearly one-half as long as body; flagellum about as long as last joint of peduncle and made up of two joints of which the proximal one is shorter than the terminal one. Thorax with coxal plates moderate, subcontiguous, and with posterior corners obtusely acuminate. Last pair of legs stronger in male than female and with carpus remarkably dilated near the base. Abdomen scarcely one-fourth as long as whole body; third to fifth coxal plates well developed and recurved. Opercular plates all provided with air spaces. Telson subtriangular, with outer part acutely produced and smooth above. Uropods with outer rami broadly lanceolate and with the inner ope extending considerably beyond the last abdominal segment. Color, variable. Length Io mm. Distribution: Europe; Ohio; New York City; Lake Cham- plain; Michigan; Maine; Massachusetts; Providence, Rhode Island; New Haven, Connecticut ; Washington, District of Colum- bia; Texas; Georgia. : The species is very common under stones, boards, etc. It is found very often in woodsheds and greenhouses. It is distinguished from the other species of the genus by its white spots on a gray to black ground; and by the antero-lateral lobes of the head which are smaller than in P. spinicornts. Metoponorthus pruinosus (Brandt). 1899. Metoponorthus pruinosus, G. O. Sars, Crust. Norway, vol. 2, p. 184, pl. 80, fig. 2. 1902. Metoponorthus pruinosus, Stoller, 54th Rept. N. Y. State Mus., p. 213. 1905. Metoponorthus pruinosus, Richardson, Bull. U.S. Nat. Mus., No. 54, p. 627. 248 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [ Bull. 1905. AMctoponorthus pruinosus, Paulmier, Bull. N. Y. State Mus., No. 91, p. 183. Fic. 82. AMetoponorthus pruinosus, Body oblong-ovate, twice as long as wide. Head twice as wide as long, with anterior margin slightly convex and antero- lateral lobes small. Eyes small, composite, situated at base of antero-lateral lobes. First pair of antennz small and inconspicuous. Second pair with first joint short ; second and third each twice as long as first ; fourth twice as long as third; and fifth one and a half times as long as preceding; flagellum composed of two joints, the first of which is twice as long as the second and, taken together, almost as long as fifth peduncular joint; whole appendage ex- tending as far as posterior margin of fourth thoracic segment. First segment of thorax a little longer than any of the others which are subequal. Antero-lateral angles of first segment pro- duced forward to surround the head and extending to base of antero-lateral lobes of head. Epimera not distinctly separated from the segments. Abdomen abruptly narrower than thorax. All six segments distinct ; first two covered laterally by the last thoracic; third, fourth, and fifth segments with lateral parts not greatly expanded; sixth segment triangular in form and half as long as wide at No. 26.] ARTHROSTRACA OF CONNECTICUT. 249 the base, apex acute and with slight concavity in its dorsal surface, Uropods with peduncle not extending as far as apex of last abdominal segment; outer ramus lanceolate and more than twice as long as last segment of abdomen; inner ramus about one-third as long as outer one. Color, posterior and lateral margins of uniform reddish brown; other parts of a lighter color. Surface of body slightly granulated. Length 9 mm. Distribution: Ohio; Kansas; California; Utah; New Mexico; Texas; Florida; Washington, District of Columbia; Virginia ; Maryland; New York City; Massachusetts; West Indies; Ber- muda; Bahamas; Europe; North Africa; Venezuela. The species is found under logs and decaying vegetable matter, in greenhouses, along walls, and in dwellings. It may be distinguished from other terrestrial forms by the fact that the abdomen is abruptly narrower than the thorax. Actoniscus ellipticus Harger. 1878. Actoniscus ellipticus, Harger, Amer. Jour. Sci., ser. 3, vol. 15, p. 373. i 1905.