o= ii 1 _D tr m 1-D i CD m CD 5 - r* ties Ecology n SMITHSONIAN INSTITUTION. UNITED STATES NATIONAL MUSEUM. REVISION OF THE DEEP-WATER MOLLUSCA OF THE ATLANTIC COAST OF NORTH AiM ER- ICA, WITH DESCRIPTIONS OF NEW GENERA AND SPECIES. PART I— BIVALV1A. BY ADDISON E. VERRILL, Professor of Zoology in Yale University, nnd KATHARINE J. BUSH, Assistant in Peal'i'dy Museum o/ Yale University. From the Proceedings of the United States National Museum, Vol. XX, pages 775-901 (with Plates LXX1-XCVI1). [No. 1139.] WASHINGTON! GOVERNMENT PRINTING OFFICE. 1898. REVISION OF THE DEEP-WATER MOLLDSCA OF THE ATLANTIC COAST OF NORTH AMERICA, WITH DE- SCRIPTIONS OF NEW GENERA AND SPECIES. PART I.— RIVAL VIA. By ADDISON E. VERRILL, Prof essor of Zoology in Yale rnirersity arid KATHARINE J. BUSH, in Pcabody Museum of Tale I'nicersify. THIS article is not intended as a review of all the known species found oft' our coasts. It is preliminary to a much more extensive report, in which full details of the distribution of all the species col- lected will be given, and for which the detailed tables have been pre- pared, giving every station for each species, with its position, depth, temperature, character of the bottom, etc. Many of the larger and more prominent species were described and figured by the senior author several years ago in various papers pub- lished in the Transactions of the Connecticut Academy and elsewhere. Tlie smaller and more difficult species were put aside at that time, for more careful study, and are now presented. The families that are most fully treated in this article are the Lediclae, Cuspidaridpe, Diplodoutida-, and Pectiimhe. These include a very large number of deep-sea species in every region, and their species are often very difficult to distinguish without long and patient microscopic study and direct comparison of large series of specimens from various localities. The present article is intended to give some of the results of studies of this kind, made during several years, of the large series of speci- mens dredged by the United States Fish Commission off our coasts from 1871 to 1887, together with those previously dredged by the senior author in the same region. PROCEEDINGS U. S. NATIONAL MUSEUM, VOL. XX— No. 1139. 775 PROCEEDINGS OF THE NATIONAL VOL. XX. 776 In order to avoid, so far as possible, the uncertainty necessarily connected with mere descriptions of these forms, we have had large cainera-lucida figures made, as carefully as possible, not only of the new species, but also of some of those previously described from our coast, for comparison. It is, therefore, to be hoped that future investi- gators may at least be able to understand the characters of the species now recognized by us, whether they agree with our determinations or not. Although the collections studied are unusually extensive, and the number of stations represented is very large, it is noteworthy that a considerable number of species were met with but once, and sometimes only a single specimen was obtained. This indicates that many addi- tional species of such small deep-sea shells would be discovered in the same region if additional dredgings should be made. Our investigations have enabled us to add to the fauna nine genera, four subgenera, and about eighty species and varieties, of which about seventy are described as new species and seven as new varieties; of these, twelve species and one variety belong to the southern fauna. The following list shows the genera in which the new species and varieties are included.1 The new genera are printed in italic: Poromya, var. 1. Cetoconcha, 2. Cetomya, 1. Lyonsiella, 2. Lyonsia, 1. Clidiophora, 1. Keunerlia, 1. Periploma, 1. Limatula, 3. Chlamys, 2. Hyalopecten, 1. Cauiptonectes, 1. Cyclopecteu, 2. Bathyarca, 2. Ben tli area. Limopsis, 2. Soiemya, 1. Nucula, 1, var. 1. Leda, 1. Lrdella, 1, var. 1. AdrantUa, 1. Microyoldia. Yoldiclla, 11, var. 1. Malletin, 2. Neilonella, 1. Tindaria, 3. MartesieUa, 1. Abra, var. 1. Macoma, 1 Montacuta. 4, var. 2. Kelliopsia. Cryptodon, 4, var. 1. . I. i-i a itl us, 6. Axiuopsis, 1, var. 1. Ajcinodon, 1. Lepta.riinis, 1. Cuspidaria, 8. Cardioinya, 2. Halonyinpha, 1. Myonera, 3. No attempt has been made to give the complete synonymy and details of the distribution. Such matters have been reserved for the final report on the collections. Unless otherwise stated, the station numbers are those of the United States Fish Commission and the serial numbers are those of the United States National Museum. The drawings, with few exceptions, were made by Mr. Alpheus H. Verrill, under the immediate supervision of the authors. Peabody Museum of Yale University, New Haven, Connecticut, January 25, 1897. 'Owing to the long delay iu the publication of this article, some of the new species and genera have been published elsewhere, so that these numbers are not now strictly correct. NO. H39. nr.KP-WATEi; Moi.i.rst'A— VKRHILL AXI> r.rsii. 777 Family PHOLADIIKE. MARTESIELLA, new subgenus. This subgeneric name is proposed for the following species, which ditt'cis from Narlcsia in having a well-delined, elongated, median, dorsal plate, posterior to the umbos, in addition to the shield-shaped one over them. MARTESIA (MARTESIELLA) FRAGILIS, new species. (Plate LXXIX, liy. ID. i Shell small, white, thin, fragile, wedge-shaped. The anterior end is very short and broadly rounded, the aperture nearly closed in our largest specimen by a pair of callous plates. The anteio dorsal margin is recurved toward the uinbos, but not appressed, and forms a deep, spiral, open cavity. The valves have a very obtuse anterior emargiuation. A broad and moderately deep sulcus runs from the beak to the ventral margin; in front of this the surface is covered by thin concentric ribs, which curve down waul at the sulcus and form a distinct angle in line with the anterior emargination and corresponding with a slight ridge on the surface; these concentric ribs are crossed by tine radiating lines, which produce tine serrations on their edges. Posterior to the sulcus the surface is marked only by irregular lines of growth, which, near it, take the form of more distinct grooves or ridges. The posterior end is prolonged, compressed, and bluntly rounded. The umbonal plate is thick, relatively large, and usually heart-shaped, with the posterior end broader and distinctly emarginate in the middle; the anterior end tapers somewhat and is blunt and angulated, or sometimes subacute. The posterior dorsal plate is long, narrow, and somewhat spatnlate or clavate, and stands well in relief above the dorsal margin, with the • edges free and the narrow anterior end running under the posterior end of the umboual plate. Length of one of the largest specimens, 7 mm.; height, 4..~> mm.: thickness, 4 mm. . Young specimens 3 or 4 mm. in length are relatively shorter and thicker than the larger ones, but even these have the anterior callous pretty well developed; the umbonal plate is usually shield- shaped, the lateral borders emarginate, in contact with the most prominent part of the uinbos; the posterior border is distinctly emarginate. and the anterior end has a central point or mucro, sometimes defined by slightly concave posterior edges. Many live specimens were found in a piece of wood floating near station 250(5, N. hit. 37° £J', W. long. 68° 8', 1885. 77X PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. Family SEMELID^E. ABRA LONGICALLIS (Scacchi), variety AMERICANA, new. (Plate LXXXIII, figs. 6, 7.) Abra longicallis VERRILL, Trans. Conn. Acad., VI. pp. 224, 278, 1884. Our specimens differ from the European form described and figured by G. O. Sars1 in having the posterior lateral tooth less remote and the cartilage-pit or chondrophore longer, the antero-dorsal margin more convex, and the whole shell relatively broader. A very few specimens were obtained at six stations between 1ST. lat. 39° 49', W. long. 68° 28' 30", and N. lat. 30° 16' 30", W. long. 68° 21'. in 924 to 2,020 fathoms, 1883-18S6. Family TELLINIDJS. MACOMA INFLATA Dawson. (Plates LXXVII, fig. 1; LXXXVIII, fig. 6.) Macoma inflata (STIMPSON MSS ) DAWSON, Canadian Naturalist, VI, p. 377, 1872.— VERRILL, Trans. Conn. Acad., V, p. 568, 1882. A number of live specimens and separate valves were obtained at six stations between N. lat. 47° 40', W. long. 47° 35' 30". and X. lat. 40^ 3', W. long. 70° 31', in 57 to 206 fathoms, 1877-1886. Murray Bay.- Dawson. Gulf of St. Lawrence. — Coll. Whiteaves. Family PETRICOLID.E. CHORISTODON ? CANCELLATUS Verrill. (Plate XCVI, figs. 2, 3.) Clioristodon '! rancellahis VKKRILL, Trans. Conn. Acad., VI, p. 435, 1885^ — BALL, I Bull. U. S. Nat. Mus., No. 37, p. 58, 1889. One valva, station 2265, off Chesapeake Bay, in 70 fathoms, 1884. Family KELLIELLID.E. KELLIELLA NITIDA Verrill. (Plates XCI, fig. 8; XCIII, fig. 10.) KeUicUa .tp. VKRRILL, Trans. Conn. Acad., VI. p. 279, 1884; Expl. Alba1r<»1. cxiv, figs. 8 a-c, 1858. — JEFFREYS, I5ritish C'onchology, II, p. 225. pi. v, lig. 3, 1863; V, p. 179, pi. xxxn, fig. 2, 1869. — Gon.n, Rep. on Invert, of Mass.. Binney's eel., p. 83, fig. 394, 1870.— TRYOX, Anier. Mar. Condi., p. 171, pi.:::.1. figs. 433, 435, 1873.— G. O. SAKS, Mollusca Reg. Arctica- Norvcgi.-r. p. 67, pi. 19, figs. 14 a-b, 1878.— JEFFREYS, Proc. Zool. Soc., London, p. 700. June, 1881. — SMITH, E. A., Report Voy. Challenger, /oil]. Lamellibranchiata, XIII, p. 201, 1885.— DALL, Bull. U. S. Nat. Mns.,No. 37, p. 200. pi. I.XYIII, fig. :,, 1889. One fresh specimen, Massachusetts Bay, off Salem, 1877. This species appears to be very rare on the American coast. In its hiuge- characters it seems to agree closely with Born la Philippi, 1836. MONTACUTA BIDENTATA (Montagu). (Plates XC1II, tigs. 7, 8; XCIV, fig. 6.) J///a bidenlata MONTAGU, Test. Brit., p. 41, pi. xxvi, fig. 5, 1803. Jlontacula bideniala FORBES and HAXLEY, Hist. Brit. Moll., II, p. 75, pi. xvm, figs. ti. <>«. J'f Hi in iid bidi-iiidtu H. and A. AI>AMS. (ionera Krc.-nl Moll., II, p. 478; III, pi. cxv, tigs. 2, 2r(. l^r.s. M»iit(ictit« hidantata JEFFREYS, British ConcLology, II. p. 208, pi. v. fig. 1. 1X63; V, p. 177, pi. xxxi, fig. 8, 1869. — <;.<>. SAR>. Mollusca Keg. An-tica- Xorvegia-, p. 69. pi. 19, figs, \la-b, 1878.— JEFFREYS. Proc. Xonl. Soc., London, p. 698, June, 1881.— VERRILI,, Trans. Conn. Acad., V, p. 571. 1882. — BUSH, Trans. Conn. Acad.. VI. p. 479, 1885; Expl. Albatross, Report U. S. Com. Fish and Fisheries for 1883. p. 590, 1885 Not Mont(t<-utn bidmtala Gould. Comparatively few specimens have been found in Long Island Sound and at Thimble Island (A. E. Verrill); Provincetown, Massachusetts (S. I. Smith and O. Harger); Vineyard Sound, 1875; Cape Cod Bay, 1870; off Block Island. 1SSO: Woods Hole, Massachusetts (Gut of Canso, and Naushon Gutters), 1882-83. From low-water to 15£ fathoms. Off Cape Hatteras, Xorth Carolina, in 14 to 48 fathoms, 1883 and 1S84. MONTACUTA BIDENTATA (Montagu), variety TENUIS, new. (Plate XC1I. fig. 7.) Shell similar to the typical M. Lidentata in form and size, but rela- tively more elongated and more nearly elliptical, with the umbos and beaks somewhat less prominent. The surface is covered with line and pretty regular lines of growth. The teeth in the right valve are strong, nearly equal in length and in the amount of divergence from the dorsal margin. They diverge more strongly and are thicker and more promi- nent, especially at the inner end, than is usual in the true Indent at a. Length of a medium size specimen 4.7 mm.; height, 2.0 mm. 780 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. A few separate valves, off Cape Hatteras, North Carolina, in 10 to 17 fathoms, 1884. MONTACUTA BIDENTATA (Montagu), variety FRAGILIS, new. (Plate XCII, fig. 8.) Shell subelliptical, inequilateral, both ends broadly rounded, thin, fragile, covered with delicate lines of growth. The umbos are flat- tened; beaks but slightly prominent. The teeth in the right valve are smaller and more delicate than in the typical bidentata, and diverge but slightly from the dorsal margin, as in that species. Length, 4 mm.; height, 3 mm. One specimen (No. 40134), station 816-17, in Narragausett Bay, in 8i to 10 fathoms, 18SO. MONTACUTA STRIATULA, new species. (Plate XCIII, tig. 9.) Shell rather large, thin and somewhat hyaline, compressed, broad- elliptical with both ends well rounded, the anterior much the longer. Antero-dorsal margin nearly straight with a gradual slope; anterior end broadly and regularly rounded, its outline forming nearly the seg- ment of a circle; ventral margin broadly and evenly convex; posterior end bluntly rounded with its dorsal margin slightly concave and slop- ing rapidly. Umbos not swollen; beaks acute and only a little promi- nent. Surface covered with fine, regular, concentric, microscopic stria- and more distant lines of growth. Interior somewhat shining with inconspicuous muscular scars. Hinge-margin thin, delicate, only slightly thickened. In the right valve there is, on each side of the beaks, a short, rather delicate, elevated, triangular tooth, terminating distally with an abrupt slope; these are nearly equal in size and length, the anterior one being slightly the shorter and more angular. They are separated by a V-shaped notch, the sides of which form nearly a right angle. In the left valve there are two thin, slightly prominent eleva- tions, scarcely worthy the name of teeth, separated by a very wide angle under the beak. Length of one of the largest specimens, 7 mm.; height, 0 mm. This species is much larger than any of our other species of this genus, and may possibly prove to be identical with M. bowman i, described and figured by Holmes.1 Owing, however, to the shortness of the description and small size of the figures, this question cannot be definitely decided without a careful comparison with authentic specimens. A few separate valves were found off Cape Hatteras, North Caro- lina, in 15 to 48 fathoms, 1883-84. 1 Post-pleioceiie fossils of South C'arolinu, p. 30, pi. VII, fig. 2, 1860. NO. 1139. / 1 /•: /•; I'.ir.i TE i; MOLLUSCA—V /•: i; i: ILL A \D j;rs/i. , ;- I MONTACUTA OVATA Jeffreys. (Plan- XCII, tigs. !l. lO.i Ti'llimya fcrrnginosa VERRILI.. Notice of Reeent Add. to Mar. Invert., Pt. ::. Pro.-. 1 1. S. Xat. Mns., III. p. 100, 1880. Muiilm-itta orata JEI- KUF.YS. 1'roc. Xoi'il. Soc., London, p. 698, pi. i.xi. fig. 4, Juno. 1881.— VEKRIJ.L, Trans. Conn. Arad.. V, p. 571, 1**-!: VI, p. i'7!«. l»l. A very few specimens, at four stations, off Newport. Uhode Island, and oil' Marthas Vineyard, ill 100 to 157 fathoms, 1880-81. MONTACUTA TUMIDULA Jeffreys. (Plates XCI1I, fig. 0; XCIV, figs. 1, 2.) Montacuta tumidula .JEFFREYS, liritisli Conchology, V, p. 177, pi. C, fig. 5, 1869. — <;. O. SAKS, Mollusca Reg. Arctica- Norvegia-. p. 00, pi. 10. figs, is a-b, 1878.— VEKKII.I., Trans. Conn. Acad., VI, pp. ±.'5, L'79, 1884; Expl. Alli mm. A few specimens were found off Cape Hatteras, North Carolina, in 15 and 1(3 fathoms, 1883-84. MONTACUTA TRIQUETRA, new species. (Plnte XCI, fig. 3.) Shell small, covered with regular concentric grooves, scarcely corn- pressed, somewhat triangular, with a slightly rostrated, angular posterior end, and a regularly rounded anterior one. Umbos a little swollen, beaks nearly central, pointed and a little prominent. The anterior and posterior dorsal margins form nearly a right angle; the anterior margin is slightly convex and passes gradually into the somewhat bluntly rounded anterior end; ventral margin broadly convex, becoming slightly incurved toward the posterior rostratiou, which is wedge- shaped, rapidly tapered, with a narrow truncate tip, defined below by a faint, radiating ridge; postero-dorsal margin is nearly straight, and slopes rapidly from the beaks. The surface is sculptured with strongly marked, smooth, rounded, concentric ridges having the upper edge smooth and recurved; these are separated by deep, regular grooves NO. 1139. DEKr-W.lTKH MOLLUSC A— VERRILL A\I> Hl's/f. 783 which appear in some .places to extend beneatli the upper edge of the ridges: on the umbos and posterior rostrum these ridges and grooves become feeble and irregular, like lines of growth. Internally tin1 sur- face is white and smooth, with the muscular scars rather strongly marked. The hinge-margin is rather thick; in the right valve there are two strong, prominent, curved, cardinal teeth, separated by a large, some- what oblique notch which extends upward into the beak; the posterior tooth is the narrower and more prominent, with the tip curved forward and upward; the anterior tooth is connected, just in front of the beak, by a bridge-like extension to the external margin, leaving between the tooth and the margin a deep submarginal groove; the inner edge of the hinge-margin is a little thickened to form a ridge continuous with the anterior tooth. In the left valve there is a distinct notch under the beak for the cartilage or resilium; in front of this is a prominent, tooth like thickening of the margin of the shell, the proximal end of which becomes tooth like, but is continuous with the rest of the hinge- margin; behind the notch there is no tooth and the margin is only a little thickened, without any special prominence. Length, about 2 mm.; height, 1.4 mm. Two valves, station 2307, off Cape Hatteras, Xorth Carolina, in 43 fathoms, 1884. TELLIMYA FERRUGINOSA (Montagu). (Plate XC, figs. 1, 8.) Tellimya ferruginosa H. and A. ADAMS, Genera Recent Moll., II, p. 479, 1858. Montacitta ferruginosa JEFFREYS, British Conchology, II, p. 210, 1863; V, p. 178, pi. xxxi, fig. 9, 1869. TeUiinya ferrtiyhioaa (i. O. SARS, Mollusca Reg. Arcticre Norvegia-, p. 70, pi. 20, figs. 1, a-c, 1X78.— VERRILL, Trans. Conn. Acad., VI, 225, pi. xxx, fig. 13, 1884. n ferrnt/inosa FiscilEi;, Manuel de Concliyliologie, p. 1027. fig. 775, 1887. i/ti frn-iii/iHosa DALL, Bull. U. S. Nat. Mns., No. 37, p. 50, pi. XLV, fig. 13, 1889. A few specimens were found at low-water at Woods Hole, Massa- chusetts (Gut of Canso), and Gutters of Naushon Island, 1882-83. The figure of the living animal published by Yerrill in 1884 has been copied by Ball, Fischer, and others. We now give additional ones. KELLIOPSIS, new genus. Type. — Montacnta eievata Stimpson. The shell, in size and form, resembles Kcllla and Montacuta. In both vaives there is a small, prominent, anterior tooth and a low, elongated, thickened posterior ridge, scarcely amounting to a tooth. The resilium is large and is attached to an elongated, oblique excava- tion on the proximal edge of the posterior tooth- like ridge, and also to a triangular pit beneath the beak: it bears a large, elongated, curved ossicle. Soft parts not observed. 7S"4 PROCEEDINGS OF THE NATIONAL MTSKUM. VOL.XX. This genus appears to be closely allied to Monlnciitu, but differs in not having a definite, raised, posterior tooth; in having a large, elon- gated posterior cartilage, bearing a large ossicle attached to a special groove jilong a tooth-like ridge; and in having the structure of the hinge in both valves nearly the same. In the position of the resiliuni it resembles Erycina, but the latter has two large teeth in both valves. KELLIOPSIS ELEVATA (Stimpson). ( Plates XCIII, figs. 2-4; XCIV, figs. 7, 8.) Montucutit bldentata GOULD, Rep. on Invert, of Mass., 1st ed., p. 59, 1841. (Not of .Montagu.) Montacuta elerata .STIMPSON, Shells of New Eng., p. 16, 1851. Cyo in in in elfvatinn H. and A. ADAMS, Genera Recent Moll., II, p. 477, 1858. Aloiitai-iita clcrtda Goi'LD, Rep. on Invert, of Mass., Binney's ed., p. 86, fig. 396, 1870. — TRYON, Amer. Mar. Couch., p. 172, pi. xxxm, fig. 440, 1873. — VERRILL, Report Invert. Anini. of Vineyard Sd., iu 1st Rep. U. S. Fish Com., pp. 394, 688, 1874 (anth. cop., p. 418). Tellimya elerata DALL, Bull. U. S. Nat. Mus., No. 37, p. 50, pi. LXVIII, fig. 6 i.-is Montacuta elevata Stiuipson), 1889. This rare species has been obtained at low-water mark, at Savin Rock, near ]S'ew Haven, Connecticut (J. E. Todd), 1871; Wellfleet, .Massachusetts (Webster), 1879; Woods Hole, Massachusetts (Gut of Canso), 1882; Naushon Island (Gutters and Sheep Pen Cove), 1882; and Narragansett Bay, in Si to 10 fathoms, 1880. Family DIPLODONTID^J. UngulinidcK FISCHER; Diplodonticlte -f- Cryptodontida Dall. CRYPTODON Turton, 1822. Type. — Cryptodon flexuosus (Montagu). The typical species of this genus have no distinct teeth in either valve, but the inner margin of the hinge-plate is more or less thickened or swollen in front of and behind the beaks. The ligament is posterior and lies in a long, curved furrow in the midst of the marginal thickening; where it commences at the beak it is marginal and external, but as it runs backward it recedes from the edge and becomes more or less internal and invisible from the exterior. Moreover, the posterior end of the shell has one or more distinct radial corrugations or plications to give the thin shell strength enough to resist the action of the large posterior adductor muscle which is attached directly upon the princi- pal plication. The pedal muscle is attached to the upper plication when the latter is present. Many writers have adopted the name of Axlnus Sowerby, 1823, for this genus; the latter name was given to a tertiary species, the structure of which is not fully determined. It may belong to a very distinct genus. Moreover, Turtou's name seems to have actual priority of publication. NO. 1139. DEEP-WATER MOLLUSCA—VERHILL AND HUSH. 785 CRYPTODON GRANDIS Verrill. Cryptodon grandis VERRILL, Trans. Conn. Acad., VI, p. 436, pi. XLIV, fig. 22, 1X85; Expl. Albatrvxs, Report U. S. Com. Fish and Fisheries for 1883, p. 575, 18*.r>.— CALL, Bull. U. S. Nat. Mus., No. 37, p. 50, pi. XLVI, fig. 22, 1889. Schizothceru.8 grandis (pars) LOCARD, Campagne du " Caudan," Aunales de 1'Uni- versitc de Lyou, p. 180, 1896. This large and interesting species, described in detail and well fig- ured in tlie first article quoted above, is a true Cryptodon, although very distinct from any of our other species. Therefore it seems strange that M. Locard has referred it to the very different genus, SchizotJuvnis of Conrad, which belongs to the Mactridre. He identifies without ques- tion a single valve, dredged by the Caudan off the coast of France, in 1,710 meters, as our species. It is, therefore, doubtful whether his speci- men is congeneric with ours, for the latter certainly has no affinity with Schisotha'rus. One live specimen and a few separate valves were dredged at three stations between 1ST. lat. 38° 29', W. long. 73° 9', and K lat. 35° 9' 50", W. long. 74° 57' 40", in 938 to 1,582 fathoms, 1883-84. CRYPTODON INSIGNIS, new species. (Plate XCI, figs. 1,2.) Cryptodon sarsii VERRILL, Proc. U.S. Nat. Mus., Ill, p. 399, 1880; Trans. Conn. Acad., V, p. 570, 1882. Shell unusually large and thick for the genus, opaque white or tinged faintly with reddish internally. Outline somewhat variable, usually broad-ovate or subquadrate, usually moderately swollen, some- times rather compressed. Umbos moderately large, not very promi- nent; beaks small and turned forward. Luuule cordate, rather large, pretty well defined. The radial folds and lobes are less marked than is usual in this genus. A well-marked fold or shallow undulation extends from the beak to the posterior margin, opposite the scar of the adductor muscle; anterior to this there is abroad, slightly raised ridge, extending from the umbo to the siphonal lobe of the margin; in front of this there is usually a broad faint depression of the surface which is scarcely apparent in many specimens; a posterior groove runs close to and nearly parallel with the postero-dorsal margin. The antero-dorsal margin, in the lunular region, is straight or slightly incurved; the anterior end is short, a little prominent below the lunule, and obtusely rounded; the ventral margin, is very broadly rounded, usually with a slightly more prominent lobe at or just behind the middle, with a more decided but obtuse projection (siphonal lobe) farther back where it joins the posterior margin, which is usually somewhat incurved, correspond- ing to the external wave-like depression, becoming convex opposite the posterior external fold; the postero-dorsal margin slopes rapidly from the beak and is sometimes broadly rounded, and at others slightly con- vex. The surface is covered with conspicuous, more or less irregular, Proc. N. M. vol. xx 50 786 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. rounded, obtuse, often prominent lines of growth with a thin yellowish brown epidermis which, under the lens, is closely covered with minute granules often arranged in more or less distinct concentric lines. The posterior hinge-margin is somewhat thickened, the ligamental groove is long and curved, diverging considerably from the margin of the shell at its posterior end and extending forward under the beak. Mus- cular scars a.nd pallial line in the largest specimens strongly marked ; the anterior scar is considerably elongated and has a number of lobes or scallops on its inner margin. Length of a medium-sized specimen, 27 mm.; height from siphonal lobe to beak, 27 mm. ; breadth, 14 mm. Length of a larger, more ovate specimen, 32 mm. ; height from siphonal lobe to beak, 35 mm. ; breadth, 21 mm. This species presents considerable variation in outline and in the degree of convexity of the valves; some are subquadrate in form, others subcordate, and others pretty well rounded, but the majority are oblong-obvate with a posterior truncation, corresponding to the broad radial groove; some of the valves are considerably inflated, but most of them are more compressed than is usual in this genus. There is also considerable variation in the prominence of the siphonal lobe and broad .radial ridge, and in the size of the lines of growth, which in some specimens are quite fine and regular, and in others unevenly developed, those on the anterior part appearing almost like concentric ribs. Many separate valves, at four stations between IS", lat. 44° 54', W. ; long. 59° 46' 45", and 2*. lat. 42° 19', W. long. 69° 47£', in 65 to 471 fathoms, 1879 and 1885. The single valve found off Cape Cod, 1879, and identified as Cryp- todon sarsii, proves to be the young of this species. CRYPTODON PLICATUS Verrill. (Plate LXXXIX, fig. 6.) Cryptodon plicatns VERRILL, Trans. Conn. Acad., VI, pp. 437, 450, 1885. One young live specimen and one imperfect valve of this character- istic and fragile species were found at two stations, off Marthas Vine- yard, in 1,073 to 1,122 fathoms, 1884. CRYPTODON CROULINENSIS (Jeffreys) Smith. (Plate XC, figs. 3, 4.) Clansina croulinensis JEFFREYS, Ann. Mag. Nat. Hist., XX, p. 19, 1847. Axinus croulinensis JEFFREYS, Brit. Con., II, p. 250, 1864. — G. O. SARS, Mollusoa Eeg. Arcticae Norvegise, p. 62, pi. 19, figs. 8, a-b, 1878. — JEFFREYS, Proc. Zool. Soc., London, p. 703, June, 1881. Cryptodon croulinensis SMITH, E. A., Eeport Voy. Challenger, Zool. Larnelli- branchiata, XIII, p. 193, 1885. Shell small, obliquely subovate, with the beaks prominent, and the anterior end considerably the longer. The antero-dorsal margin is »o. 1139. DEEr-WATEK MOLLUSCA— VERHILL A.\l> IlfSH. 787 nearly straight, sloping- rapidly from the beak; the anterior end is dis- tinctly produced, evenly rounded; the ventral margin is slightly but regularly convex to the lower posterior fold; the posterior end is marked by two distinct plications separated by a rather prominent ridge which, at the margin, appears as a rounded projection separating two reentrant curves; the postero-dorsal margin is convex, sloping rapidly to the upper plication. The ligameiital area is relatively large, long, elliptical, defined by a distinct groove. Internally the hinge- margin is considerably thickened, especially directly under the beak, where there is a slight swelling; the posterior ligament occupies a^ very distinct groove, and extends forward under the tip of the beak. Length, 3..~> mm.; height, 3.75 mm. The shell here referred to this species appears to agree well with the figures and descriptions given by G. O. Sars. It pretty closely resem- bles some varieties of C. gouldii. The principal differences exter- nally are in the somewhat more produced anterior end and the longer and straighter antero-dorsal margin; the posterior plications are also Jess strongly developed. Found in small numbers at about thirty stations north of Cape Cod, between N. lat. 43° 4-U', \V. long. 09° 22', and K". lat. JL)0 30', W. long. 70o 3S'? in 13 to 73 fathoms, 1873-1879. CRYPTODON CROULINENSIS (Jeffreys) Smith, variety ALTUS, new. (Pint.- LXXXVIII, figs. 1, 2.) Shell higher than long, larger than the common form. TJmbos promi- nent, elevated and turned forward, so as to leave a rather large, con- spicuous, flattened, lunular area, which is bordered externally by a slight ridge, followed by a concave depression in the surface, which forms a slight indentation in the anterior margin, and resembles the posterior plication, but is more shallow. The antero-dorsal margin in the lunular region is slightly concave, but slopes very rapidly; the anterior end is a little more produced than the posterior, but both are decidedly short; the ventral margin is pretty evenly rounded; poste- • riorly there are two distinct plications; the lower or larger one is mod- erately sunken and extends from the beak to the posterior margin, the upper one is much shorter and narrower and defines the narrow, lanceolate, ligamental area; each produces a decided indentation in the margin, that caused by the lower one being more sharply defined and shorter than the other, these are separated by a well-defined, curved, radiating ridge which extends a little below the margin; the postero-dorsal margin is strongly convex, evenly rounded, with a rapid slope; the hinge margin is considerably thickened, especially beneath the beak, and in the right valve forms a distinctly raised tubercle. Length, 5 mm.; height, G mm. Eastport, Maine, 1870. Another specimen, from station 29L>, is slightly smaller. Length, 788 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. 4.5mm.; height, 5.25 mm. In this the anterior or upper plication is much less distinct than in the type, and it is therefore possible that this feature is abnormal. CRYPTODON EQUALIS, new species. (Plato XCI, figs. 5, 6.) Shell of moderate size, grayish white, rather swollen, pyriform, usu- ally a little higher than long, but sometimes the height and length are about equal. Umbos rather prominent; beaks median, conspicuously raised above tbe margin and curved strongly forward so as to produce a rather deep, broad, cordate, but ill denned lunular area. Anterior and posterior ends nearly equal. The dorsal margin slopes rapidly on both sides of the beak; anteriorly, in the lunular region, it is nearly straight; the anterior end is pretty evenly rounded, forming a continu- ous curve with the ventral margin, which forms nearly a semicircular curve; the posterior end has one broad, shallow undulation which causes a slight incurvature in the postero-ventral margin ; above this the dorsal margin is very slightly convex and forms an angle at the commencement of the fold. The ligameutal area is marked by a smooth, long, lanceolate, slightly sunken portion, clearly separated by an incised line. The general surface is covered with slightly marked, more or less irregular lines of growth. The hinge-margin is moderately thickened and is essentially the same in both valves. There is a well marked swelling both before and behind the beak and a more con- spicuous one immediately under it; a less conspicuous thickening, with its external edge excurved, extends along the postero-dorsal margin, in the ligamental region. Muscular and pallial scars indistinct. Length, 5 mm.; height, 5£ mm.; thickness, 4 mm. Some specimens are somewhat larger than this. In the large series which we have of this species there is some variation. In some cases the form is less swollen, the length is slightly in excess of the height, so that the general outline is more evenly rounded. The species is, however, notable for the equality of the anterior and posterior ends and the presence of the single slight undulation. Cryptodon t/otildii somewhat resembles this species, but differs in being longer in proportion to its height, in its more com- pressed form, and in having two distinct folds or undulations. It is also closely allied to C.flexuosus of Europe, but is more pyriform in shape and lacks the anterior angulatiou noticeable in that species. Taken at thirty-two stations, between N. lat. 47° 40', W. long. 47° 35' 30", and N. lat. 37° OS', W. ioug. 74° 33', in 94 to 1,537 fathoms, 1873- 1886. CRYPTODON PLANUS, new species. (Plate LXXXVIII, figs. 3, 4.) Shell small, well-rounded, the length and height about equal, with the beak small, prominent, nearly central, curved strongly forward, NO. 1^39. DEEP-WATER MOLLUSC A— VEKHILL AND 7?r.5 AXINOPSIS CORDATA, new species. (Plate XCVII, figs. 5, 6.) Shell small, white, smoothish, rouuded or somewhat cordate, longer anteriorly, with small, little prominent beaks curving forward. Antero- dorsal margin a little convex, sloping gradually and passing somewhat abruptly into the anterior margin, which is broadly and obtusely rounded; ventral margin strongly convex, somewhat produced in the middle; posterior margin pretty evenly rounded, except in the middle, where there is a slightly produced portion corresponding to the plica- tion; postero-dorsal margin strongly convex in the middle. The sur- face is marked by fine, microscopic, concentric strioe and irregular lines of growth which, on the umbo, appear as slight undulations. The liga- mental area is relatively large, prominent in the middle, and defined by a distinct groove, beyond which there is a well-marked but low radiat- ing ridge or plication which forms an inconspicuous projection at the margin ; anterior to this there is a very slight wave-like depression of the surface, much as in most species of Cnjptodon. The hinge-margin is decidedly thickened; in both valves there is a rather large, obtuse tooth just below the beak, from which it is separated by a rather large space for the ligament which runs backward for a short distance in a conspicuous submargiual groove, becoming internal distally; anteriorly the groove is narrow and outside the margin. Length, about 2 mm.; height, the same. This species is referred to the genus Axinopsis with some doubt, although it has the distinct cardinal tooth and ligament-groove. It has, however, a single posterior plication similar to that seen in some species of Cryptodon; but the character of the plications vary in that genus, in some cases being very strong and in others obsolete, or nearly so. In fact, the genus Axinopsis can hardly be distinguished from it except by the distinctly developed cardinal tooth, which is only par- tially differentiated from the proximal end of the anterior hinge-plate. A few separate valves and two live young were found at six stations between N. lat. 40°, W. long. 71° 14' 30", and N. lat. 35° 42', W. long. 74° 54' 30", in 43 to 202 fathoms, 1880-1884. The young specimens from stations 870 and 943 are referred to this species with considerable doubt, as they have a much more rounded outline, although the hinge-margin is similar. AXINODON, new genus. Type. — Axinodon ettipticus, new species. Shell thin, rounded or ovate, without plications. Hinge with one or two small or subrudirnentary teeth. Ligament internymphal, poste- riorly so far internal that its inner end, distally, is attached below the inner edge of the hinge-plate, and therefore covers its entire breadth. 796 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. AXINODON ELLIPTICUS, new species. (Plates XC, figs. 5, 6; XCII, fig. 1.) Shell small, nearly smooth, swollen, transversely elliptical and some- what oblong, with rather prominent nmbos and with the beaks con- siderably behind the middle and curved forward. The antero-dorsal margin is decidedly convex and somewhat excurved, the anterior end is longer and a little broader than the posterior; both are nearly evenly rounded; the ventral margin is broadly rounded and nearly straight for a short distance along the middle; the postero-dorsal margin is con- vex and merges into the posterior end in a regular curve. The lunular area is rather distinct, but without any very definite boundary. The surface is nearly smooth, covered only with fine, close lines of growth, which, under the microscope, appear as delicate, raised lines, separated by grooves of about the same width; this sculpture is very regular over most of the surface, but on the umbos some of the ridges are so large as to appear like small undulations. The interior surface is smooth and white ; the muscular scars are indistinct ; the hinge-margin is rather thin; the posterior ligament is prominent, wedge-shaped, widest distally, and occupies a distinct groove covering the whole breadth and extending about one third the length of the postero-dorsal margin and running forward under the beaks. In the left valve there are two slightly raised, minute, obscure, rounded teeth under the beak, of which the anterior is a little more distinct than the other; farther forward, and separated from the latter by a slight notch, there is an elongated thickening of the margin forming a sort of lateral tooth or lamina and separated from the outer edge by a narrow groove. In the right valve the anterior tooth-like thickening is less distinct and there is only a very slight rounded swelling of the lunular margin under the beak. Length, 3.5 mm.; height, 3 mm. Two live specimens (No. 35175), station 2096, 8. lat. 39° 22' 20", W. long. 70° 52' 20", in 1,451 fathoms, 1883. LEPTAXINUS, new genus. Type. — Lepiaxinus minutus, new species. Shell small, short-ovate, inequilateral, with the anterior end the longer, and rounded, and the posterior end tapered and angulated, with a slight plication. Hinge-plate well developed, with a delicate, lateral tooth on both sides of the beak in the right valve, and one pos- terior lateral tooth in the left valve; in both valves with the proximal end of the hinge-plate enlarged and thickened near the beak, that of the left valve most developed and rising into a blunt tooth-like promi- nence. Ligament commencing under the beak and running back on the ventral side of the posterior hinge-plate, so that for the greater part of its length it is internal. NO. 1139. DEEP-WATER MOLLUSCA—VEERILL AXI> l',l sil. 797 This genus differs from Cryptodon in the more internal position of the ligament and in having distinct lateral teeth. From Ajchuxl<>n, in the stronger hinge plate, in the presence of the lateral teeth, in having a posterior plication, and in lacking distinct cardinal teeth. LEPTAXINUS MINUTUS, new species. (Platr LXXXIX, li-js. :;-5.) Shell minute, broadly ovate, with a slightly produced obtuse point near the middle of the posterior end, and a somewhat produced, broadly rounded anterior end. Beaks behind the middle, rising a little above the dorsal margin and turned forward, leaving a small, rather deep lunular area. Antero-dorsal margin a little convex, sloping but little; anterior margin broadly and evenly rounded, forming nearly a semicircle, and passing continuously into the ventral margin, which is a little more broadly rounded ; the posterior margin is somewhat angular, with a distinct prominence a little below the middle, where the radial ridge terminates, below this for a short space the mar- gin is nearly straight or slightly incurved; above, the postero-dorsal margin is straight as far as a slight angle in the ligamental area, above which it is convex to the beak. The hinge-margin is a little thickened, and in the left valve forms a rather prominent and somewhat angular tooth just below and slightly in front of the beak ; the ligamental groove is barely visible on the inner face of the posterior hinge-margin, and runs forward as a narrow groove beneath the beak; in the r:ght valve there is a somewhat less prominent tooth just under the beak, behind which the ligamental groove forms a distinct notch in the margin. Under the microscope there is seen in both valves a distinct submargi- nal ridge with a conspicuous groove behind it, commencing a consider- able distance behind the beak and running in and along the inner hinge-margin; there is also in the right valve a short, indistinct groove along the end of the hinge-margin in front of the beak. Externally a rather shallow, depressed undulation runs from the beak to the pos- tero-ventral margin; behind it is a narrow, but slightly prominent, radial ridge running to the posterior angle; back of or above this a rather short ligameutal area projects beyond the margin. The surface is covered with a thin, greenish yellow epidermis and is marked by tine, pretty regular, parallel, raised lines of growth, and also faint and rather numerous radiating lines which are not visible except under a high power. Length, nearly 2 mm.; height, If mm. One live specimen (Xo. 45080), station 949, X. lat. 40° 3', W. long. 70° 31', in 100 fathoms, 1881. 798 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. xx. Family ASTARTID^. ASTARTE NANA (Jeffreys?) Dall. Aatarte nana DALL, Bull. Mus. Comp. Zool., XII, p. 261, pi. vn, figs. 6a, 6ft, 1886; Bull. U. S. Nat. Mus., No. 37, p. 46, pi. vn, figs. 6a, 66, 1889. •* A single valve, which agrees perfectly with Ball's figures, quoted above, was found at station 2307, off Cape Hatteras, North Carolina^ in 43 fathoms, 1884. South to Sombrero, in 22 to 196 fathoms. — Dall. Family CUSPID ARID^E. In the classification of this family we have adopted the groups pro- posed by Messrs. W. H. Dall and E. A. Smith as defined by Mr. Dall.1 We, however, consider his two subgeneric groups, Cardiomya and Halonympha, as distinct genera. CUSPIDARIA UNDATA Verrill. (Plates LXXII, fig. 1; LXXVIII, figs. 3, 4.) Nefrra undata VERRILL, Traus. Conn. Acrid., VI, pp. 223, 277, 1884; Expl. Alba- tross, Report U. S. Corn. Fish and Fisheries for 1883, p. 574, 1885. Not Myonera undata DALL, Bull. Mns. Comp. Zool., XII, pp. 302, 304, 1886; Bull. U. S. Nat. Mus., No. 37, p. 68, 1889 (in part). Three live specimens and two valves were found at stations 2098 and 2566, off Chesapeake Bay, in 2,221 and 2,680 fathoms, 1883 and 1885. Fragments obtained by the Blake near Havana, Dominica, and St. Vincent, in 450 to 611 fathoms, are erroneously referred by Mr. Dall to this species. Our shell is certainly not a Myonera. We have a fragment of a left valve from station 2655, N. lat. 27° 22', W. long. 78° 7' 30", in 338 fathoms, found among Foramiuifera, which belongs to a strongly undulated species, with a short, angular, sub- acute rostrum defined below by a rather dee]) groove at which the concentric sculpture changes abruptly. The beak is prominent and turns strongly backward. The cartilage-plate is strong, deeply con- cave, and directed backward; a moderately elevated internal rib runs backward from the umbonal region to the posterior muscular scar. The shell is thin aud has deep internal grooves corresponding to the external ridges. Judging by the lines of growth, the shell was short- ovate, broadly rounded anteriorly, aud having posteriorly a short, angular, subacute rostrum ; the escutcheon is concave and well-defined by a small, sharp ridge. This fragment seems to belong to an unde- scribed species of Myonera. It can, however, hardly be the same as Mr. Dall's species, as he states that in his "there is no buttress or appearance of an internal rib." 'Bull. Mus. Comp. Zool., XII, p. 292, 1886; XVIII, p. 441, 1889. NO. 1139. DEEP-WATER MOLLUSCA— VERRILL AND BUSH. ?[)9 CUSPIDARIA LAMELLOSA (M. Sars) Dall. (Plate LXXIV, fig. 10.) Neasra lamellosa VERRILL, Trans. Conn. Acad., V, p. 561, 1882; VI, p. 277, pi. xxx, fig. 3, 1884; Expl. Albatross, Report U. S. Com. Fish and Fisheries for 1883, p. 574, 1885. Cuspidaria lamellosa DALL, Bull. Mus. Comp. Zool., XII, p. 294, 1886; Bull. U.S. Nat. Mus., No. 37, p. 66, pi. XLV, fig. 3, 1889. Comparatively few specimens, at twelve stations, between N. lat. 40° 2' 49", W. long. 68° 49', and N. lat. 37° 59' 30", W. long. 73° 48' 40", in 319 to 555 fathoms, 1880-1886. A few specimens occurred which differ from the typical form in hav- ing hut five or six concentric lainelhe visible on the antero-ventral portion of each valve and only conspicuous unequal lines of growth on the rest of the surface. CUSPIDARIA TURGIDA, new species. (Plates LXXII, fig. 7; LXXVII, fig. 4.) Shell rather large, thin, delicate, translucent, of a pinkish white color within, long-oval, with prominent, posteriorly directed umbos, and narrow, rather long posterior rostrum. The beaks are central, rather acute and turned distinctly forward. The antero-dorsal margin is slightly convex, forming a broad curve; the anterior end is a little prolonged in the middle but otherwise pretty evenly rounded; the ventral margin forms a regular, broad curve becoming strongly incurved at the base of the rostrum; the postero-dorsal margin is straight at first, but slightly concave along the rostrum. The cartilage-plate is small and very oblique, and in the right valve, is separated by a dis- tinct notch from the lateral tooth, which is long and low, with a rounded summit and a long, gradual, posterior slope; there is no trace of buttress or clavicle. In the left valve the hinge-margin is thin, and nearly simple both anteriorly and posteriorly. The exterior surface is covered with a thin, yellowish gray epidermis and is marked with irregular, rather conspicuous lines of growth; on the rostrum there is a distinct diagonal ridge running from the beaks to the lower margin. -Length, 22 mm.; height, 12 mm.; breadth, 11 mm.; distance from cen- ter of beak to end of rostrum, 12 mm. ; to extreme anterior end, 12 mm. In form, general appearance, and length of rostrum, this species is intermediate between C. glacial is and C. rostrata, but the umbos are more oblique and there are obvious differences in the hinge. One live specimen (No. 78789), station 2714, N. lat. 38° 22', W. long. 70° 17' 30", in 1,825 fathoms, 1886. 800 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. CUSPIDARIA ROSTRATA (Spengler) Ball. (Plate LXXII, fig. 6.) Nea-ra rostrata VERRILL, Trans. Conn. Acad., V, p. 562, pi. LVIII, fig. 39, 1882; VI, p. 277, 1884; Expl. Albatross, Report U. S. Com. Fish and Fisheries for 1883, p. 574, 1885. — SMITH, E. A., Report Voy. Challenger, Zool. Lamellibranchiata, XII, p. 35, 1885. Cuspidaria rostrata BALL, Bull. Mus. Cornp. Zool., XII, p. 294, 1886; XVIII, p. 444, 1889 ; Bull. U. S. Nat. Mus., No. 37, p. 66, 1889.— LOCARD, Campagnedu Caitdan, Annales do 1'Universite de Lyon, p. 177, 1896. This species was obtained at about fifteen stations between 1ST. lat. 40° 6' 50", W. long. 70° 34' 15", and K. lat. 38° 31', W. lolig. 73° 21', in 65 to 156 fathoms. South to Barbados in 65 to 1,639 fathoms. — Ball. CUSPIDARIA GLACIALIS (G. O. Sars) Ball. (Plates LXXI, tig. 9; LXXIII, fig. 5; LXXV, ng. 9.) Neara glacialis G. O. SARS, Mollusca Reg. Arctic* Norvegue, p. 88, pi. 6, figs. 8, a-c, 1878.— VERRILL, Trans. Conn. Acad., V, p. 562, pi. XLIV, figs. 10, a-b, 1882; VI, p. 277, 1884; Expl. Albatross, Report U. S. Com. Fish and Fisheries for 1883, p. 574, 1885.— SMITH, E. A., Report Voy. Challenger, Zool. Lamelli- branchiata, XIII, p. 35, 1885. Cuspidaria glacialis DALL, Bull. Mus. Coinp. Zool., XII, pp. 294, 303, 1886; Bull. U. S. Nat. Mu , No. 37, p. 66, 1889. Cuspidaria arctica var. glacialis DALL, Bull. Mus. Conip. Zool., XVIII, p. 444, 1889; Proc. U. S. Nat. Mus., XII, p. 280, 1889. Cuspidaria glacialis BUSH, Bull. Mus. Comp. Zool., XXIII, p. 226, 1893. Not Cuspidaria artica (M. SARS). This very common species was dredged at many stations from 1ST. lat. 44° 26'. W. long. 62° 10', to N. lat. 37° S', W. long. 74° 33', in 62 to 828 fathoms. South to the Gulf of Mexico, in 64 to 1,467 fathoms. — Ball. • CUSPIBARIA MEBIA, new species. (Plates LXXI, figs. 5, 6; LXXIII, fig. 6.) Shell of moderate size, resembling a medium-sized C. glacialis (Sars), in form, but decidedly more swollen, with the rostrum narrower and more distinctly defined by a stronger ventral emarginatiou. Umbos large, prominent, and swollen, with strongly incurved and very promi- nent beaks. The antero-dorsal margin is a little convex and slopes rapidly to the evenly rounded anterior end; the ventral margin is regu- larly curved and is rather more convex than in C. glacialis, and shows a very decided emarginatiou at the base of the rostrum; the postero- dorsal margin is nearly straight but slopes from the beak to the end of the rostrum which is of moderate length and tapers from the base to the narrow, subtruncated end; it has no distinct diagonal ridge, but is separated from the body of the shell by a strongly marked depression. The surface is nearly smooth but is covered with fine lines of growth NO.H39. DEEP-WATER MOLLUSCA— VF.VUI1.L AXD KUSH. 801 which are most distinct OH the rostrum. The hinge-margin is thin. The right valve has a thin, low, much elongated posterior lateral tooth which runs nearly parallel with the dorsal margin, above which it pro- jects in a broad curve; the cartilage-plate is small, very oblique, and closely united with the tooth from which it is separated by a faint, curved notch; no buttress. In the left valve there is no lateral tooth, and the cartilage-plate is very small, slightly prominent, with a curved inner edge. The inner surface of the shell is smooth and the muscular scars are faint. Length of an average specimen, 13 mm.; height, 8 mm.; breadth, 6.5 mm.; beak to end of rostrum, 8.-") mm.; beak to anterior end, 6 mm. This species is allied to C. glacialls, from which it differs in its more swollen form, more oblique anterior end, more prominent ventral mar- gin, more clearly denned rostrum, and straighter postero-dorsal margin. The hinge shows still more decided differences; the lateral tooth of the latter is stouter, more prominent, and less prolonged; the cartilage- plate is smaller and less distinctly defined. From C.fraterna it differs in being less produced ventrally and in having a longer rostrum with much straighter dorsal margin and a much longer lateral tooth. This is a common species off Marthas Vineyard and has been taken at about fifteen stations between N. lat. 40° 10' 15", W. long. 70° 26', andN. lat. 39° 50', W. long. 70° 5-1' IS", in 63 to 155 fathoms, 1880-1884. A broken valve, station 362, N. lat. 42° 1', W. long. 69° 34', in 106 fathoms, 1879, is also referred to this species. CUSPIDARIA PARVA, new species. (Plates LXXIY, tig. 9; LXXVII, tig. 7.) Shell small, delicate, elongated, inequivalved, having a general resem- blance in form to the very young of C. obesn and C. fraterna. Umbos small, rather prominent; beaks small and incurved. The autero-dorsal margin is moderately convex and slopes regularly to the evenly rounded anterior end; ventral margin very broadly rounded, with a decided incurvature at the base of the rostrum, corresponding to the marked depression of the surface; postero-dorsal margin slopes rapidly at first and is usually concave along the rostrum, which is moderately long (the length varies in different specimens), narrow, with an obtusely rounded or subtruncated end. It is crossed by a distinct diagonal ridge, above which there are several small, raised, radial lines; the surface is elsewhere nearly smooth or presents a microscopic, faintly granulose appearance. The left valve is the larger and considerably overlaps the right along the ventral margin and siphonal region; the right overlaps the left along the postero-dorsal margin; the rostrum is a little bent toward the left in some specimens. The hinge-margin is delicate, with the anterior margin a little everted; cartilage-plate minute, sunken, in the right valve well separated from the prominent, Proc. N. M. vol. 802 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. rather elongated lateral tootb ; the left valve also lias a small, elongated, tooth-like expansion posterior to the cartilage-plate. Length, 4.5 mm.; height, 2.25 mm.; breadth, 1.5 mm. This species may easily be mistaken for the young of C. obesa and C. fraterna; the structure of the hinge is, however, characteristic. A comparatively few specimens, at seven station, between N. lat. 41° 28' 30", W. long. 65° 35' 30", and 35° 49' 30", W. long. 74° 34' 45", in 515 to 1,290 fathoms, 1883-1886. CUSPIDARIA VENTRICOSA, new species. (Plates LXXII, fig. 5; LXXVI, fig. 6.) Shell large, rather solid, swollen, with a ventral enlargement and a moderately elongated, tapered rostrum. Umbos swollen and promi- nent; beaks incurved. Antero-dorsal margin at first nearly straight, then broadly rounded with the extreme anterior end a little prominent; ventral margin decidedly excurved in the middle, corresponding to the exterior swelling; at the base of the rostrum slightly concave; postero- dorsal margin somewhat concave, the most so at the base of the ros- trum, which is obtusely rounded at the end. Exterior covered with very distinct lines of growth and irregular, stronger, concentric grooves. C-i the rostrum there is an obtuse, diagonal ridge running to the ven- tral angle of the tip; between this and the dorsal margin there are two others less distinct. The anterior hinge-margin is decidedly thickened in both valves and projects inward with a thick, rounded edge, most conspicuous in the right valve, in which it is abruptly much narrowed near the cartilage-plate; in this valve the lateral tooth is short, stout, obtuse, very prominent, and situated close to the beak, its length along the margin not much exceeding its height; cartilage-plate small, rela- tively wide, oblique, directed backward and downward, and closely united to the lateral tooth, there being only a slight, rounded notch between. Length of the larger specimen, 30 mm.; height, 29 mm.; breadth, 18 mm.; beak to end of rostrum, 16 mm.; beak to anterior end, 17 mm. Another specimen is 25 mm. long; 17 mm. high; 12 mm. broad. Four valves, at three station, between N. lat. 40° 29', W. long. 66° 4', and K lat. 38° 27' 30", W. long. 70° 54' 30", in 349 to 1,769 fathoms, 1882-1886. This species has some resemblance to C. glacialis, but is a stouter and more swollen shell, with a relatively larger rostrum, much more elon- gated and less prominent lateral tooth, and very different cartilage- plate. The latter does not have the swollen ventral region, character- istic of our species, nor the diagonal ribs on the rostrum. NO. 11 39. DEEP- WA TEE MOLL USCA— VEEEILL AND B USH. 803 CUSPIDARIA ARCTICA (M. Sars) Dall. (Platos LXX1, !ig. 1>; LXXIV, tiff. 7.) \rvegi;c, p. Xf>, pi. t>, figs. 5, a-c, 1878. — SMITH, E. A., Report Voy. Chctllvitf/er, Zool. Lamellibranchiata, XIII, p. 35, 1885. Cuspidaria ardica DALL, Bull. Mus. Comp. /o<".l., XII, p. 294, 1886. Not Neccra arctica YERRILL, Amer. Journ. Science, VI, p. 440, 1873. A single imperfect valve from station 70, south of Halifax, Nova Scotia, in 190 fathoms, is referred to this species. Though worn and slightly broken, it agrees closely with Sars' figure, but it cannot be fully grown, for it measures but 14 mm. in length and 11 mm. in height. CUSPIDARIA FORMOSA, new species. (Plates LXXIV, fig. 6; LXXIX, fig. 3.) Shell short, high, and swollen. Umbos prominent; beaks incurved. Anterior portion broadly rounded, a little produced at the end, with the dorsal margin convex and a little excurved; the ventral margin is broadly and evenly rounded; the rostrum is short, broad at base, much tapered; the postero- dorsal margin is nearly straight at first, then slightly concave and a little upturned. The exterior is covered with uneven lines of growth between which the surface is microscopically striated and more or less iridescent. The color of the single specimen is pale pink, externally and internally. The right valve has a promi- nent, triangular lateral tooth with its base prolonged parallel to the margin of the shell ; it is separated by a decided notch from the cartilage- plate, which is of moderate size, ovate, somewhat oblique, with its inner edge rounded and prominent. Length, about 16 mm.; height, 13 mm.; breadth, 10 mm.; beak to end of rostrum, about 9 mm.; beak to anterior end, 8 mm. A single, much broken, specimen (No. 78313), station 2706, N. hit. 41° 28', W. long. 65° 35', in 1,188 fathoms, 1886. CUSPIDARIA FRATERNA, new species. (Plates LXXI, figs. 7, 8; LXXV, fig. 6.) Shell similar to Cuspidaria obex<( (Loven), moderately large, consider- ably swollen, rather thick and firm. for the genus, with a moderately long, tapered rostrum. The umbos are rather prominent and swollen, with the strongly incurved beaks nearly in contact. The anterior end is broadly rounded with a regularly curved, convex dorsal edge which rises nearly to the height of the umbos; the ventral margin is a little protuberant. The postero-dorsal line slopes with a slightly concave outline to the end of the rostrum ; on the ventral margin there is a dis- tinct incurvature corresponding to a wave-like depression on the surface, 804 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL xx. defining the base of the rostrum. The surface is nearly smooth and somewhat glossy, covered with fine lines of growth which become more prominent and irregular on the rostrum, which has no distinct diagonal line. The hinge-margin is somewhat thickened; the right valve has a rather short, prominent, obtuse, triangular lateral tooth only slightly separated from the cartilage-plate by a concave margin ; the cartilage- plate is small, very oblique, with the inner edge curved and not at all angulated. Muscular scars and pallial line indistinct; no buttress. Length, 13 mm.; height, 9 mm.; breadth, G mm.; from beak to end of rostrum, 8 mm.; from beak to anterior end, 7 mm. Found at about thirty stations between 1ST. lat. 40° 2' 49", W. long. 68° 49', and N. lat. 37° 23', W. long. 73° 53', in 302 to 984 fathoms. This species resembles C. obcsa (Loven) in form; it is, however, a larger species with a firmer and more swollen shell; the ventral margin is more prominent, so that it has a relatively higher form and is broader at the base of the rostrum. The hinge shows more decided differences, for in C. obesa the lateral tooth is smaller, shorter, and closely approxi- mated to the cartilage-plate which is distinctly angulated, the inner end being acute and separated from the tooth by a small angular notch. CUSPIDARIA OBESA (Loven) Dall. ( Plate LXXV, fig. 7.) Necara obesa LOVKN, Ind. Moll. Scand. Occid., p. 48, 1846. — VERIULL, Trans. Conn. Acad., V, p. 563, pi. XLIY, fig. lOc, 1882; VI, p. 277, 1884 (in part) ; Expl. Albatross, Report U. S. Com. Fish and Fisheries for 1883, p. 574, 1885 (in part). — SMITH, E. A., Report Voy. Challenger, Zool. Lamcllibraucliiata, XIII, p. 43, 1885. Cuspidaria obesa DALL, Bull. Mus. Comp. Zool., XII, p. 295 (not pi. in, fig. 1), 1886; Bull. U. S. Nat. Mus., No. 37, p. 66 (not pi. in, fig. 1), 1889. Not Necvra pellucida STIMPSON. This species has been found at about twenty-four stations between H". lat. 43° 23', W. long. 68° 30', and N. lat. 35° 12' 10", W. long. 74°57/15//, in 96 to 811 fathoms, 1873-1887. It is recorded by Mr. Dall from off Barbados in 100 fathoms and off the coast of California in 16 fathoms. After a careful study and comparison of the numerous species belonging to the family Cuspidaridte we have been able to satisfac- torily prove that the form described by Stimpson as Necera pellucida is quite distinct from that described by Loven as N. obesa, with which it has been so long confounded. NO. 1139. DEEP-WATER MOLLUSCA—VEER1LL AXI> BTSH. 805 CUSPIDARIA PELLUCIDA (Stimpson). (Plates IAX V. lig. X; I AX VI, U-. 8.) Necerapelhtcida STIMPSOX, Invert. Grand Maiian, p. 21, pi. i, fig. 13, 1853.— GOULD, Invert. Massachusetts (2d ed.), p. 61, fig. 378, 1870.— VEKKILL, Check-list, p: 24, 1*7! I. Necera sp. VERRILL, Expl. AUwtroxs, Report U. S. Com. Fish and Fisheries ibr 1883, p. 574, 1885. Not Nea'ra obesa LOVKN. Shell small, much swollen, with a strongly tapered, somewhat pro- duced rostrum. Umbos relatively large and prominent, beaks minute, strongly incurved. The anterior portion is broadly and evenly rounded, the margin forming nearly a semicircle, with the dorsal margin strongly convex and excurved, rising nearly as high as the uuibos; the ventral margin is broadly rounded but distinctly incurved at the base of the rostrum which is rather narrow distally, obtusely rounded at the tip and slightly upturned ; the postero dorsal margin slopes considerably, is nearly straight at first but becomes slightly concave on the rostrum. External surface nearly smooth but usually showing more or less prom- inent lines of growth, most distinct on the distal part of the rostrum which is destitute of a distinct diagonal line. The right valve has a short, very prominent, strongly curved lateral tooth rising close to the beak, the most prominent part being near the proximal end which rises rather abruptly from the very minute cartilage plate from which it is not separated by a notch; just in front of the beak, the hinge-margin is distinctly thickened, sinuous, and a little prominent, forming a sort of tooth, separated from the lateral tooth only by the minute sunken cartilage-plate; the left valve also has a slight, sinuous thickening of the margin in front of the cartilage plate. Length of one of the largest specimens, 4.5 mm.; height, 3mm.; breadth, 3 mm.; beak to end of rostrum, 3 mm.; beak to anterior end, 2.5 mm. This species has been taken at Eastport Harbor; Bay of Fundy, near Grand Man an Island; and at about twenty-one stations between N. lat, 47° 40', W. long. 47° 35' 30", and N. lat. 35° U' L>0", W. long. 74° 59' 10", in 52 to 516 fathoms, 1868-1886. The specimens here described are from the Bay of Fundy, near Grand Manan Island and Eastport Harbor, very near the locality where Doctor Stimpson's types were obtained. In former articles we have united this species with G. obesa (Loven). A careful reexam- inatiou of a large series of specimens of both forms has convinced us that they are distinct but closely related species. In G. obesa the anterior portion is more produced, giving the shell a more ovate out- line; the rostrum is broader and rather more upturned; the cartilage- plate is relatively much larger, more prominent, and angular at the edge, and in the right valve is separated from the lateral tooth by an 800 PROCEEDINGS OF THE NATIONAL MUSErV. VOL.XX. angular notch; while the tooth itself is relatively smaller, shorter, less prominent, and more distinctly triangular in form. CUSPIDARIA SUBTORTA (Sars). (Plates LXXIII, fig. 1; LXXIV, figs. 4, 5.) Newra subtorta SARS, G. O., Mollusca Reg. Arcticsa Norvegise, p. 87, pi. 6, figs. 6, a-c, 1878. — JEFFREYS, Ann. Mag. Nat. Hist., p. 234, September, 1877; I'roc. Zool. Soc., London, p. 937, November, 1881. — SMITH, E. A., Report Voy. Clial- lenyer, Zool. Lamellibraucliiata, XIII, p. 35, 1885. Shell inequivalve, rather short, relatively high, much swollen in the middle, with tumid umbos aud a short, tapered, somewhat upturned rostrum. The anterior portion is broadly rounded, the margin forming nearly a semicircle; the autero-dorsal margin is strongly convex and slightly excurved; the ventral margin is evenly rounded, except at the base of the rostrum where it is distinctly incurved, especially in the right valve ; the postero-dorsal margin is very strongly concave in the left valve and less so in the right. The rostrum is separated from the body of the shell by a sinuous depression and has a poorly denned diagonal ridge ; it is a little bent to the left and, when viewed from above, appears slightly twisted. The surface of the shell is nearly smooth, but shows distinct lines of growth anteriorly, and especially on the superior part of the rostrum; the epidermis is very thin, yellowish white, more or less wrinkled on the rostrum ; the hinge-margin is rather- strong; the lateral tooth in the right valve is large, rather elongated, rather prominent, obtusely triangular, and not separated from the very small, narrow, oblique, sunken cartilage-plate by a notch; in the left valve there is a small, short, prominent tooth arising from the poste- rior margin of the cartilage-plate and separated from the posterior hinge-margin by a distinct angular notch. Length, 8 mm.; height, 6 mm.; breadth, about 5 mm. One live specimen (No. 52545), station 2499, N. lat. 44Q 46' 30", W. long. 59° 55' 45", in 130 fathoms, 1885. This species appears to be identical with the European sitbtorta. It differs from all of our other species in having a distinct tooth-like tubercle behind the cartilage-plate in the left valve. The inequality of the valves and the twisted rostrum give the shell a peculiar aspect. CARDIOMYA ABYSSICOLA, new species. (Plates LXXIII, iig. 4; LXXIV, fig. 1; LXXVII, fig. 9.) Shell rather large, swollen, with tumid umbos ; outline elongate-ovate, with a narrow, rather elongated, tapered, slightly excurved posterior rostrum, the tips divergent and gaping; the anterior end is broadly round, with the dorsal and ventral margins convex, the latter narrow- ing gradually posteriorly with a slight sinus at the base of the rostrum ; the postero-dorsal margin is concave, so that the end of the rostrum is NO. 1139. DEEP-WATER MOLLUSC A— VERRILL AND HUSH. 807 somewhat upturned. The entire body of the shell is covered with numerous narrow, elevated, radiating- ribs, separated by much wider concave interspaces, some of the widest of which have a small second- ary rib in the center toward the margin; the ribs increase in elevation and strength posteriorly, toward the base of the rostrum, but never become broad 5 for a short distance on the base of the rostrum the ribs are nearly obsolete but become prominent again on its dorsal and ter- minal portions; this part is also crossed by irregular raised lines of growth which cross the ribs obliquely; the inner surface is covered with rounded grooves corresponding to the external ribs, separated by convex ribs of about the same width; these become obsolete ante- riorly and posteriorly. The hinge-margin in the left valve is only a little thickened and slightly excurved, the cartilage-plate is central, stout, regularly ovate in form, with a thickened inner margin; in the right valve there is a prominent, rather stout, elongated posterior tooth, the anterior end of which joins closely the cartilage-plate, leav- ing scarcely any notch between ; the highest part of the tooth is near the middle, the slope, however, is a little steeper anteriorly; a deep groove separates the tooth from the thin, slightly excurved dorsal mar- gin; anteriorly the margin is but slightly thickened, and shows a very narrow, beveled edge externally for the attachment of the thin liga- ment; a similar but more distinct ligamental groove extends from the beak to the base of the rostrum; there is a short, rather stout, rib-like clavicle or buttress running from beneath the middle of the tooth obliquely backward and downward in the direction of the base of the rostrum ; a less prominent buttress is also present in the left valve. Length of one of the largest specimens, 25 mm. ; height, 15 mm.; thickness, 14 mm.; from beak to end of rostrum, 13 mm.; to autero- ventral margin, 12 mm. One badly broken valve is considerably larger than this. There are also two young live specimens which measure about G mm. in length and 3.5 mm. in height. Their form is somewhat narrower and longer than in the adult, and the rostrum appears rather longer and narrower; the postero-dorsal margin is nearly straight; the ventral margin is decidedly concave at the base of the rostrum; the shells are very thin, somewhat transparent and glossy, and have about twenty six sharply denned, considerably elevated, nearly equal, nar- row ribs on the body of the shell, separated by much wider spaces; the edge of the left valve overlaps that of the right, especially along the base of the rostrum. In general appearance this species greatly resembles C. multicostata Verrill and Smith. It differs, however, in having a regularly more ovate form with the anterior region somewhat narrower and more prolonged and the postero- ventral margin less incurved at the base of the ros- trum, so that the latter is broader and less differentiated. The exter- nal costa? differ in being narrow and sharp, separated by broad concave interspaces, and of nearly uniform size, there being no marked contrast between those on the anterior and posterior portions of the shell, 808 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. although the elevation and distance between them gradually increase posteriorly, while in the former they are broadly rounded and separated for the most part by narrow interstices. The hinge also differs consid- erably; the cartilage-plate is less prominent and broader than that of multicostata, and the tooth in the right valve is longer and not so prominent and scarcely forms a notch at its junction with the cartilage- plate; anteriorly the margin is very thin and simple with a very nar- row, linear, ligamental groove -along its outer edge, while in the former the groove is broader and its inner edge is raised almost in the form of a lateral tooth. It also resembles C. costellata var. corpulenta Ball in the character of the costa?, but the latter is much shorter and higher in form and has a very short, ill-defined rostrum. Two young live specimens, two separate valves, and some fragments were taken at three stations, between N, hit. 40° 29', W. long. 66° 14', and K lat. 36° 47', W. long. 73° 9' 30", in 1,685 to 1,813 fathoms, 1885-86. CARDIOMYA MULTICOSTATA Verrill and Smith. (Plate LXXIII, fig. 3.) Neaera multicostata VERRILL, Trans. Conn. Acad., V, p. 559, pi. LVIII, fig. 40, 1882; VI, p. 277, 1884; Expl. Albatross, Keport U. S. Com. Fish and Fisheries for 1883, pi. xxx, fig. 129, 1885.— SMITH, E. A., Eeport Voy. Challenger, Zool. Laniellibranchiata, XIII, p. 36, 1885. Not Cardiomya striatn BALL, Bull. Mus. Comp. Zool., XII, p. 298, pi. in, fig. 10, 1886; Bull. U. S. Nat. Mus., No. 37, p. 66, pi. in, fig. 10, 1889; Proc. U. S. Nat. Mus., XII, p. 281, 1889. Cardiomya striata DALL, Bull. U. S. Nat. Mus., No. 37, pi. LXV, fig. 129, 1889. Not Cardiomya costeUata (DESHAYES) var. curta DALL, Bull. Mus. Comp. Zool., XII, p. 297, 1886. Necera multicostata var. curta VERRILL, Trans. Conn. Acad., V, p. 560, 1882. This comparatively rare species was found at but eight stations off Marthas Vineyard, in 85 to 158 fathoms, 1880-1882. Although this species resembles Cardiomya striata (Jeffreys) in the character of its sculpture, the marked difference in outline, especially in its clearly defined rostrum, render it advisable to keep the two forms separate until a careful comparison of the hinges can satisfactorily decide the question of their identity. The two valves designated as variety curta have the radiating ribs rounded and not angular, but fewer in number than the typical form, and must be distinct from curia of Jeffreys, which Mr. Dall makes a variety of costellata of Deshayes. HO. 1139. DEEP-WATER MOLLUSC A— VERRILL AND BUSH. 809 CARDIOMYA PERROST RATA Dall. (Pliit.es LXXIII, fig. 2; LXXIV, fig. 3.) Ncwra perrostrata VEURILL, Trans. Conn. Aead., \ , p. 501, 1XS2; VI, p. 277, 1884. Cardiomya perrostrata DALL, Bull. Mus. Comp. Zool., XII, p. 1'ltH, pi. n, figs. 3a, 3ft, 188(5; Bull. U. S. Nat. Mus., No. 37, p. 66, pi. n, figs. 3a, 3I>, 1889. Only a few specimens were obtained from seven stations between N. lat. 40° 15' 30", W. long. 70° 27', and X. lat. 39° 4(3' 30", W. long. 70° 54', in 58 to 325 fathoms, 3880-1884. South to Granada, in 339 to 416 fathoms. — Ball. CARDIOMYA GEMMA, new species. (Plates LXXI, figs. 3, 4; LXXIV, fig. 11.) Neaira pan cistriata BUSH, Trans. Conn. Acad., VI, p. 473, 1885. Not Myonera paiicistriata DALL, Bull. Mus. Comp. Zool., XII, p. 302, 1886; Bull. U. S. Nat. Mus., No. 37, p. 68, 1889; Proc. U. S. Nat. Mus., XII, p. 233, pi. xin, fig. 12, 1889. Cardiomya sp. BUSH, Bull. Mus. Comp. Zool., XXIII, p. 227, 1893. Shell small, inequivalved, thin, fragile, translucent, bluish white, somewhat ovate, with a well-defined rostrum. TJinbos smooth, a little prominent; the beaks small, inconspicuous. The antero-dorsal margin is convex and rises distinctly above the beaks so that the greatest height of the shell is in front of them; thence it slopes rapidly to the somewhat prominent anterior end; the ventral margin is broadly rounded with a slight angle at the termination of each radial rib, decidedly incurved at the base of the rostrum which is a little elon- gated, nearly straight, somewhat tapered, and rather upturned distally ; the postero dorsal margin is depressed and somewhat concave. Each valve has three conspicuous, prominent, thin, elevated, distant, radial ribs on the posterior half and a fourth less distinct one at about the middle; this is rudimentary in the left valve; none of them reach the umbos. The surface is also covered with very delicate lines of growth; the rostrum does not have a diagonal ridge. The hinge-margin is thin and delicate; the right valve has a small but prominent, moderately long lateral tooth separated from the very minute cartilage-plate by a distinct notch. The lateral tooth is supported by a small buttress. Length, 5 mm.; height, 3 mm. A few specimens off Cape Hatteras, North Carolina, in 1<> and 17 fathoms, 1884. 810 PROCEEDINGS OF THE NATIONAL ML'SEf'M. VOL.XX. CARDIOMYA GLYPTA Bush. (Plat<>s LXXI, fig. 1; LXXYI, figs. 3, 7.) Netera costata BUSH, Trans. Conn. Acad., VI, p. 472, pi. XJ,Y, fig. 21, 1885; Expl. Albatross, Report U. S. Com. Fish ami Fisheries for 1883, p. 587, 1885; not Sowerby, 1834. Cardiomya ornatissima DALL, Bull. Mus. Comp. Zool., XII, p. 296, 1886; Bull. U. S. Nat. Mus., No. 37, p. 66, pi. XLI, fig. 21. 1889. A few specimens were found at two stations off Cape Hatteras, North Carolina, in 48 fathoms. South to Guadaloupe, in 2 to 124 fathoms.— Ball. In addition to the published description it should be stated that the antero-dorsal margin of the right valve rises into a distinct, prominent, obtuse lobe in front of the tooth; this lobe overlaps the margin of the left valve when the shell is closed. There is a small buttress beneath the posterior lateral tooth. One broken valve, considerably larger than the type, has in the intervals between the three primary ribs two or three small secondary ones; on the anterior end six ribs are visible, of which one or two are larger than the rest, so that altogether about thir- teen or fourteen ribs can be counted; some of these are, however, very small and extend only part way to the urn bo; even the largest do not extend over the extreme part of the umbo. Mr. Dall considers this species to be identical with D'Orbigny's orna- tissima, but we see no sufficient reason for uniting the two forms. The name costata was used by Sowerby in 1834. HALONYMPHA STRIATELLA, new species. (Plates LXXII, figs. 2, 3; LXXVII, fig. 10.) Shell small, thin, broadly and obliquely ovate, with a narrow, short rostrum. Unibo swollen. Beak behind the middle. The antero-dorsal margin is broadly and nearly evenly convex ; the anterior end is evenly rounded; the ventral margin is broadly convex with a slight incurva- ture at the base of the rostrum, which is short, narrow, and obtuse at the end; the postero-dorsal margin is strongly concave and slopes rapidly. In the region of the umbo the surface is lustrous and nearly smooth, but marked with faint, parallel lines; elsewhere it is closely covered with very regular, fine, raised concentric lines separated by incised lines of about the same width or narrower; on the rostrum there is a faint diagonal ridge posterior to which the concentric lines are irregular. The interior surface is smooth and lustrous but the external lines show through by transparency. In the right valve there is a small, sharp, triangular tooth projecting inward with a very small cartilage-pit in front of and confluent with it; slightly farther forward there is another small, slender tooth rising nearly parallel with the NO. 1139. BEEP-WATER MOLLUSC A— VERRILL ANl> I'.rSTT. 811 margin; external to tbis there are remnants of a small anterior liga- ment occupying a short furrow. Commencing behind the beak and extending to the base of the rostrum, there is a comparatively large and prominent lamelliform process rising from beneath the margin and projecting downward, with the face portion broadly rounded, and its upper surface concave. Above the base of this, and extending from near the beak to about the middle of the rostrum, is a narrow, slightly thickened ridge separated from the dorsal margin by a narrow furrow. Length, 6 mm.; height, 4.5 mm.; breadth, about 3 mm. One valve, station 2055, among Foraininifera, X. lat. 27° 22', W. long. 78° 1' 30", in 338 fathoms, 1886. This species has considerable resemblance to H. clariculata Dall, but the latter is more regularly ovate in form, and has a much shorter and broader rostrum, and somewhat coarser sculpture. The posterior shelf-like clavicle also differs in form, being quite narrow for a consider- able distance next the cartilage-pit, and more expanded distally. The shell described and figured by Smith1 under the same name appears to be a distinct species, and may be identical with our shell, for it has nearly the same form and agrees closely in the narrow tapered rostrum. The figure of the interior, however, in that case, is incorrect, owing to the omission of the clavicle, and apparently the substitution of the hinge of the left valve for the right. MYONERA GIGANTEA Verrill. (Plate LXXVI, figs. 4, 5.) Necera glgantea VERRILL, Trans. Conn. Acad., VI, pp. 223, 277, 1884; Expl. Alba- tross, Report U. S. Com. Fish and Fisheries for 1883, p. 574, 1885. Three imperfect, dead specimens have been found at three stations between N. lat. 38° 22', W. long. 70° IT 30", and N. lat. 37° 56' 20", W. long. 70° 5V 30", in 1,825 to 1,917 fathoms, 1883 and 1886. MYONERA RUGINOSA (Jeffreys) Verrill and Bush. (Plates LXXII, fig. 4; LXXIV, fig. 2.) Near a ri<x« JEFFREYS, Proc. Zool. Soc. London, p. 042, pi. LXXI, fig. 7, Novem- ber, 1881. — SMITH, E. A., Report Voy. Challenger, Zool. Lamellibranchiata, XIII, p. 35, 1885. Shell small, short, broad-ovate, not much swollen, with a short, wide, gaping, obliquely truncate rostrum. Umbos small, prominent, not much swollen; beaks small, prominent, incurved, smooth -and shining. The anterior portion is evenly rounded, nearly semicircular; the antero- dorsal margin is convex and prominent; the ventral margin is broadly and evenly rounded, except at the base of the rostrum where it is sin- uous and incurved; the postero-dorsal margin is nearly straight to the 1 Report Voy.Challenger Zool. Lamellibranchiata, XIII, p. 52, pi. ix, figs. 8-8&, 1885. 812 PROCEEDINGS OF THE NATIONAL MUSEVV. VOL.XX. end of the short rostrum which has a distinct, median, diagonal ridge or angulation and another less distinct one at its base. The surface of the shell is thickly covered with very numerous, and crowded, concentric, more or less irregular, raised lines of growth which give it a finely lam- ellose appearance when viewed under a lens. These lines become more crowded, more prominent, and form two sinuous waves in crossing the rostrum. Color, in alcohol, white tinged with reddish brown. The hinge-margin is delicate; the right valve has no lateral tooth but shows a slight thickening of the posterior margin; the cartilage-plate is small, ovate, directed backward. Length, 6 mm.; height, 4.5 mm.; breadth, 3 mm. One live specimen (No. 52544), station 2570, N. lat. 39° 54', W. long. 07° 5' 30", in 1,813 fathoms, 1885. "Porcupine Expedition, 1870," off Cape Moudego, in 740 to 1,095 fathoms. — Jeffreys. MYONERA LIMATULA Ball. (Plate LXXIV, fig. 8.) Nea>,ra limatula DALL, Bull. Mus. Comp. Zoiil., IX, p. 112, 1881. — SMITH, E. A., Report Voy. Challenger, Zool. Lamellilmmchiata, XII, p. 35, 1885. Mi/onera limatula DALL, Bull. Mus. Comp. Zool., XII, p. 304, pi. in, fig. 5, 1886; Bull. U. S. Nat. Mus., No. 37, p. 68, pi. in, fig. 5, 1889. A single live specimen (No. 38171) was taken at station 2048, N. lat. 40° 2', W. long. 68° 50' 30", in 547 fathoms, 1883. MYONERA (?) PRETIOSA, new species. (Plate LXXVII, fig.5.) Shell small, very thin and fragile, nearly transparent, compressed, elongate-oval with a well-defined, somewhat elongated rostrum. Umbo prominent, scarcely oblique and nearly smooth. The antero-dorsal mar- gin is convex, anterior end evenly rounded; ventral margin broadly convex, becoming incurved at the base of the rostrum; postero-dorsal margin nearly straight. The antero dorsal region is distinctly exca- vated in front of the beaks. The body of the shell is ornamented with ten or more thin, distinct, slightly raised, concentric riblets separated by much wider interspaces. On the rostrum there are two well-marked minutely spinulous keels between which are delicate lines of growth; the first runs from the beak quite close to and parallel with the dorsal margin ; while the second extends from the umbo diagonally across the rostum to its lower edge. Length, 6 mm.; height, 3 mm.; breadth, about 2 mm. This shell has no very close resemblance to any hitherto described. One valve, station 2655, N. lat. 27° 22', W. long. 78° 7' 30", in 330 fathoms, among Foraminifera, 188G. As but a left valve was found, the true position of this species can not be decided. NO. 1139. DEEP-WATER MOLLUSC A — VERRILL AND BUSH. Family POEOMYIDyE. POROMYA SUBLEVIS Verrill, variety MICRODONTA Dall. (Plates LXXVI, figs. 1, 2; LXXXVII. fig. 1.) Poromya suMeris VKKRILL, Trans. Conn. Acad., VI, pp. 221, 277, pi. xxxn, fig. 21, 1884; Expl. Albatross, Report U. S. Coin. Fish and Fisheries for 1883, p. 574, pi. xxx, fig. 128, 1885.— BALL, Hull. Mus. Corup. Zool., XII, pp. 281, 282, 1886; XVIII, p. 448, 1889 (variety?); Bull. U. S. Nat. Mus., No. 37, p. 68, pi. LXV, tig. 128, 1889. Poromi/d mh-rodonta BALL, Proc. U. S. Nat. Mus., XII, p. 290, pi. vin, fig. (5, 1889 (variety?). Shell rather large, thick, well-rounded, cordate, iuequivalved, very tumid, with very large, prominent umbos which are strongly curved forward spirally; beaks large; lunule small, cordate, often not very distinct. The shell varies considerably in outline and size and eleva- tion of the umbos; in most specimens the height equals or slightly exceeds the length; the outline of the cavity of the shell is usually somewhat elliptical, the length decidedly exceeding the height, but sometimes it is nearly circular. The anterior and posterior margins are usually pretty evenly rounded; the ventral margin usually projects a little in the middle; the beak is situated in front of the median line. Externally the shell is nearly smooth and is covered with a thin, closely adherent, brownish-yellow epidermis; under a lens the sur- face shows minute raised points or granules which are arranged in radial rows that become more distinct and crowded posteriorly but for the most part disappear on the most prominent part of the umbos. These granule-like points are variable in number and distinctness, in some specimens being nearly obsolete and in others distinct and regu- larly arranged; the epidermis often also shows fine lines of growth; the beaks are smooth and shining. The left valve has a posterior, wave-like, radial depression, and behind this a low, rounded ridge projecting at the margin as a slight siphonal lobe; in the right valve, the corresponding lobe and depression are only faintly marked in most cases. The right valve is larger than the left and overlaps it consider- ably along the ventral margin and both in front of and behind the beaks. The interior is pearly and often shows radial striatious. The hinge-margin is considerably thickened and strongly curved; the right valve has a large, thick, somewhat rounded tooth just beneath the beak and aduate to the inner surface of the shell, for some distance within the cavity of the beak and to the thickened edge behind the beak, but separated from the anterior margin by a deep, curved furrow in the lunular area; the lunular margin is convex and somewhat everted, separated from the rest of the anterior margin by a slight notch. The ligament is rather long and well-rounded and its groove extends for- ward in a curved furrow under the beak; it extends backward in a curved line parallel with the margin of the shell for some distance 814 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.SX. behind the tooth. External to the posterior part of the ligament there is a submarginal thickening or fold, especially in the right valve. In the left valve the central tooth is represented by an irregular, bilobed, or somewhat V-shaped thickening of the margin, of which the anterior part, situated just in front of the beak, is the more prominent; but this varies in form in different specimens. The postero-dorsal margin along the ligamental region is less thickened but has a distinct rounded ridge inside the ligament. Length of one of the largest specimens, 10 mm. ; total height, 10 mm. ; height of cavity, 12 mm.; breadth, 10 mm. In a more rounded speci- men the length is 15 mm.; total height, 10 mm.; height of cavity, 13.5 mm.; breadth, 14 mm. A few dead specimens of the typical form (sublcvis) have been taken at five stations between N. lat. 39° 15', W. long. 08° 8', and K lat. 37° 50' 20", W. long. 70° 57' 30", in 1,594 to 1,917 fathoms, 1883-1880. Several live and dead specimens of the varietal form (microdonta) have been taken at eight stations between N. lat. 39° 26', W. long. 08° 3' 30", and N. lat. 30° 47', W. long. 73° 9' 30", in 1,031 to 1,859 fathoms, 1885-1880. Mr. Dall extends the range south to Patagonia, in 122 to 1,035 fathoms. Our specimens show considerable variation in form as well as in the prominence of the cardinal tooth in the right valve, and thus unite the extreme forms P. sublems Yerrill, and P. microdonta Dall. CETOCONCHA ATYPHA, new species. Shell short-ovate, nearly equilateral, and nearly equally rounded at both ends, judging from the lines of growth, limbos rather prominent, but less so than in several allied species. Beaks rather prominent and curved strongly forward, but not spiral. Surface somewhat shining and slightly iridescent where rubbed, covered with a very thin, yellow- ish epidermis with very numerous, minute, granule-like elevations which are arranged in regular radiating lines, and are much the most numer- ous on the posterior end where the radial rows are closely crowded and the granules in each are also near together; on tlie center the rows and granules are more distant, so that the number is only about half as great in the same space; on the anterior end they are so scattered that the radial rows are indistinct and the granules are a little larger; on the lunular area they are nearly obsolete. The anterior end and lunu- lar area are marked by rather conspicuous lines of growth which, near the dorsal margin, take the form of distinct, raised, concentric ridges. The antero-dorsal margin is nearly horizontal and rises up, in a side view, in an acute edge, a little higher than the level of the beak, so as to produce a broad, compressed, lunular margin. When viewed from above, this part of the margin forms a very marked obtuse angle with the posterior hinge-margin. The postero dorsal margin is also nearly NO. 1139. DEEP-WATEU MOLLUSCA—VETtRTLL AND BUSH. 815 horizontal, slightly convex or nearly straight; the ligament is very prominent behind the beak, extending backward in a conspicuous groove nearly to the posterior end, and terminates anteriorly in a deep narrow groove directly under the beak. In the left valve the inner edge of the posterior hinge-margin is somewhat sinuous; just behind the beaks, opposite the most prominent part of the nmbos, it is thick- ened and somewhat revolute, decreasing both in thickness and eleva- tion to a shallow indentation of the margin; back of this, it increases regularly in thickness and prominence and is again revolute along the posterior part of the ligamental furrow. There is no central tooth nor any distinct resilium. In the right valve the posterior hinge-margin is even more thickened and revolute just back of the beaks, and the in- dented, thinner portion, at the end of the prominent part of the liga- ment, is more marked. The ligamental groove is consequently less conspicuous, being partially concealed by the revolute margin. The antero-dorsal margin is compressed and projects strongly upward, rising distinctly above the umbos in a side view and is more convex than in the left valve. There is also a slight elevation within the dor- sal margin directly below the beaks, which might be considered the rudiments of a tooth. The largest specimen, when perfect, would be about 15 mm. long. Two very much broken valves, station 2229, N. lat. 37° 38' 40", W. long. 73° 10' 30", in 1,423 fathoms, 1884. This species somewhat resembles Cetocltonca nitida (Verrill)1 Dall.2 It is however more oblong, with the urnbos much smaller and less prominent and the beaks less spiral and nearer together. The granu- lation of the surface is somewhat stronger and more generally distrib- uted. The ligamental groove is longer, deeper, and the ligament itself is more prominent behind the beaks. The angnlation of the hinge-mar- gin of the left valve in a horizontal plane is a peculiar feature not found in the other related species and indicates that the valves are decidedly unlike in form, but the right valve is too much broken to show the anterior margin. CETOMYA species. A broken left valve (No. 52013) from station 2481, N". lat. 44° T 30", W. long. 57° 1G' 45", in 110 fathoms, resembles Poromya (Getomya) elongata Dall, from the West Indies and Barbados, in 100 to 119 fath- oms. It is, however, too incomplete for determination without direct comparison with authentic specimens. It is larger and more strongly truncate posteriorly than Poromya granitlnld, (Nyst) Forbes and Hanley, and the granules are coarser and not so numerous. It differs, moreover, very strongly in the hinge characters, for the hinge-plate is much thinner and the large tooth in the left valve is wanting in our species. 1 TJiracia iiilida Verrill, Trans. Conn. Acad., VI, p. 221, pi. xxxn, fig. 22, 1884. 2 Cctochonca nitida Dall, Bull. Mus. Comp. Zool., XII, p. 281, 1886. 816 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. Family VEBTICOBDID^B. VERTICORDIA GRANULIFERA (Verrill) Dall. (Plates LXXXVII, fig. 2; XCV, figs. 2, 3, 4.) Pecchiolia granulifera VERRILL, Trans. Conn. Acad., VI, pp. 434, 448, 450, 1885. Verticorilia grani/era DALL, Bull. Mus. Coinp. Zool., XII, p. 286, ]886. Terticordia granulifera DALL, Bull. U. S. Nat. Mus., No. 37, p. 66, 18S9. In addition to the published description, it should be stated that in the type-specimen (No. 44838), the luuular area is small, deeply sunken, with the corresponding internal margin very much thickened, forming a strong", curved, tooth-like projection having" a rounded summit, reach- ing strongly above the margin of the shell when seen in a profile view; behind this, directly under the beak and beneath the overhanging margin, there is a triangular space or notch for the reception of the prominent tooth of the opposite valve; this is followed posteriorly by a short, triangular, shelf-like projection, a little beneath the margin, which has a depression on its upper surface for the reception of its ligament but shows, in this specimen, no notch or scar corresponding to the ossicle. Directly under the strongly incurved beak there is a slight, thin groove in which the front part of the ligament was attached. The postero-dorsal edge is a little thickened and projects inward beyond the general line of the margin ; its outer surface has a smooth, slightly excavated groove, extending parallel with the edge, for some distance; this portion was overlapped by the projecting edge of the opposite valve. A very large specimen (No. 78679) from station 2713, which measures 21 mm. in length, 22£ mm. in height, and 10 mm. in thickness, has, in the right valve, directly beneath the beak, a very strong, high, curved, pointed, angular tooth attached by a very broad, thick base, a con- siderable distance within the margin. Behind the ossicle, well within and nearly parallel with the margin for its entire length, is a conspicu- ous shelf-like ridge against which the projecting edge of the opposite valve rests. The ossicle is strong, somewhat rectilinear in outline, with the posterior end deeply forked, the inner surface strongly con- vex, the outer strongly concave, with thick, somewhat beveled edges, to which the ligament is attached. Interior surface somewhat pearly. Scars and pallial line not very clearly defined. But four specimens, beside the type, have been found at four stations between N. lat. 40° 9' 30", W. long. 67° 9', and N. lat. 36° 47', W. long. 73° 9' 30", in 1,350 to 1,859 fathoms, 1884-1880. NO. 1139. DEKr-WATER MOLLUSC A— VERRILL AND BUSH. 817 Family LYOXSIELLUXK. LYONSIELLA SUBQUADRATA (Jeffreys.) (Plate LXXXVII, tig. 3.) I't'ccliiolia si32, pi. i.xx, lig. 3, November, 1881.— Not DALL, Bull. Mue. Comp. Zool., XII, p. 272, 1XS6. Our specimen seems to agree in every respect, except size, with the original description and figure as given by Jeffreys, ours being consid- erably larger. The ninbo is prominent and the beak is curved strongly forward, pro- ducing a deep lunular area which is denned neither by a groove nor a ridge. The surface is everywhere covered with small bnt prominent granules which are numerous, pretty evenly spaced, and arranged somewhat distinctly in radiating rows which, under the microscope, are defined by slight radial ridges uniting those of the same row. The granulations are easily visible with slight enlargement. Under the compound microscope they have the form of elevated, acute cones and blunt tubercles, their height usually greater than their diameter, except on the umbo, where they are low and rounded. Internally the surface is everywhere marked with small, deep pits looking like punctures made by a fine needle, and corresponding to the external grannies. The hinge margin is thickened and entirely edentulous, as described by Jeffreys. Posterior to the beak there is a distinct groove in the thick- ness of the margin for the reception of a ligament. Beneath the beak there is a slight, oblique, marginal notch or slit for the reception of the resilinm, running back within and underneath the dorsal margin, so that it is scarcely visible in a direct front view. This shell appears to be identical with the species originally described and figured by Jeffreys under the name of Pecchiolia sulquadrata. Mr. Ball has evidently found an entirely different species in the Jef- frey's collection under this name, which he has referred to the genus Callocanlia and subgenus Vesicomyn^ belonging to an entirely different family from our shell. In order to avoid confusion the shell examined and described by Mr. Dall should receive a distinct specific name; we therefore propose CaUocardia ( Vcsicomya] dalll. Mr. Dall states that "the sparsely set, microscopic tubercles can only be observed with a magnifier; to the eye the surface looks shining and smooth," which shows the surface to be quite different from that of our shell. In his shell there are also two cardinal teeth in each valve. One valve (No. 78800), station 2714, N. lat. 38° 22', W. long. 70° 17' 30", in 1,825 fathoms, 1880. North of the Hebrides, in 542 fathoms; and off Cape Mondego in Vigo Bay, in 740 to 1,095 fathoms. "Porcupine Expedition, 1.SG9-70."- Jeffreys. Proc. N, M. vol. xx 818 PROCEEDINGS OF THE NATIONAL MUSED! . VOL. xx. LYONSIELLA CORDATA, new species. (I'latr Xl'V, figs. 1.x.} Shell rather large and firm for the genus, somewhat translucent bluish white, swollen, cordate, with a posterior obtuse prominence. I inbos prominent, turned forward spirally; beaks small, strongly incurved. Lmmle small, cordate, denned only by one of the ordinary tine radial ridges; the part that lies immediately under the beak is deeply sunken with the edge pinched up into a prominent keel. The antero-dorsal margin is strongly convex and prominent in the lunu- lar region, but not so high as the umbos; the anterior margin is but slightly convex and nearly perpendicular to the axis of the shell; the ventral margin is strongly convex and somewhat produced iu the mid- dle, farther back it is but slightly convex ; the posterior end is obtusely rounded, decidedly prominent but not angular; the postero-dorsal mar- gin is a little convex and slopes gradually. The surface is covered with about sixty delicate, radiating, raised lines or riblets which are crossed by fine lines of growth, the thin, brownish or grayish green epidermis often rising into small points at their intersection, especially anteriorly and posteriorly; these riblets become coarser and more dis taut anteriorly, and are lacking on the lunule. The ligament is thin and strong and extends backward along nearly the whole of the dorsal margin and curves spirally under and around the beak in the region of the resilium, so that the two come almost in contact. The hinge mar- gin, in front of the beak and hmular area, is strongly convex and pro- tuberant, rising nearly to the height of the umbo; posteriorly it is convex and thin in both valves; in the left one it is strengthened by a slight marginal rib within the ligamental furrow; both of these are less evident in the right valve. There are no teeth in either valve. The ossicle is relatively large, oblong, somewhat saddle-shaped, narrowest and truncated anteriorly, broadest and forked posteriorly, the divisions acute. The resilium beneath the ossicle is well developed, dark brown, and extends forward and upward to the margin, beneath the beak. Length of the largest specimen, 11 mm.; height, 12 mm. Another is II mm. long; 11.5 mm. high; 9 mm. broad. Two living specimens and one valve, at three stations between !N". lat. 39° 15', W. long. 680 8/? alui N. lat. 37° 38' 40", W. long. 73° 16' 30", iu 1,423 to 1,825 fathoms, 18S4-1SXIJ. Family LYONSID^E. LYONSIA GRANULIFERA, new species. (Plate XCV, tig. 1.) Shell oblong, truncated posteriorly, narrowed and rounded anteriorly. Umbo rather prominent with the beak in front of the middle and curved forward; limular area considerably sunken. Anterior end evenly HO. 1139. itKKP-WATKli MOLLUSCA—VERRILL AND BUSH. 81!) rounded with the dorsal margin rapidly sloped ; ventral margin broadly and evenly rounded; posterior end somewhat obliquely truncated with- out any definite boundary, but with a distinct depression extending from under the beak to about the middle of the posterior margin ; postero- dorsal margin nearly straight, longer, and sloping less rapidly than the anterior. The entire surface is covered with minute, irregular, raised, granules and pretty distinct, but irregular, lines of growth and slightly raised, distant, thin, radiating lines running from the umbo to the margin, except on the posterior end where the lines of growth become more prominent; these radial lines are however, in many places, rather faint and seem to consist mainly of the thin, brownish epidermis, which is lacking in certain parts. Minute grains of sand and shells of Foram- iuifera are firmly adherent to the surface, mainly along the radial lines, and especially posteriorly. The interior is white, lustrous and but slightly nacreous. Muscular and pallial scars indistinct. The hinge-margin is thin ; in the left valve the anterior border is somewhat thickened in the luuular area and terminates abruptly in a rounded, tooth-like shoulder just under the beak; the posterior margin shows a slightly raised elongated, roughened area for the attachment of the resilium, commencing under the beak and running back for some dis- tance within the margin, on its nearly vertical inner surface, so that it is scarcely visible in a front view. Ossicle not observed. Ligament very thin, occupying a groove along the posterior margin. Length, ID mm.; height, 13 mm.; breadth, 9 mm.; from the beak to the antero-dorsal angle, 7 mm. ; to the postero-dorsal angle, 12 mm. One valve (No. 525(51), station 2402, N. lat. 45° 22', W. long. 58° 43' 45", in 75 fathoms, 1885. This species is allied to L. urenosa (Moller) with which it agrees very closely in the character of the external surface and structure of the hinge. It differs in its longer, more ovate form, in its more produced anterior end, and in its less swollen umbo. Family P CLIDIOPHORA INORNATA, new species. (Plate XCV, figs. 5, 6.) Shell small, much compressed, very inequilateral, posterior end nar- rowed, somewhat accumulate, the right valve flat or slightly convex and the left valve a little swollen. Limbos not prominent; beaks small and appressed. The antero-dorsal margin is slightly convex and slopes rapidly to the bluntly rounded anterior end; the ventral margin is broadly rounded and slightly prominent, considerably behind the middle, beyond which it is incurved to meet the posterior rostral angulation; the posterior end is produced into a short, narrow, sub- truncated, slightly upturned rostrum, its lower angle formed by a some what prominent, radial rib or ridge, extending from the beak (on the 820 PROCEEDINGS OF THE NATIONAL MUSEUM. voi,xx. left valve) ; the postero-dorsal margin is usually slightly concave, but is sometimes nearly straight, and in some cases decidedly concave, and slopes gradually to the superior aiigulation of the rostrum; the liga- mental area is narrow, deep, and long, extending for nearly the entire length of the dorsal margin, and is clearly denned by a marginal ridge which is sharper on the left valve. In most specimens this valve is marked by a slight, ill-defined groove running from the beak to the antero- ventral margin, where it often forms a slight emargination, but is often scarcely discernible, except by the change in the direction of the lines of growth and character of the epidermis. The surface of the left valve is covered with irregular concentric ridges and rather uneven lines of growth; the right valve usually shows rather regular, concen- tric undulations on which are numerous fine, pretty regular, lines of growth; this valve is also usually marked by faint, and rather indis- tinct, radiating, impressed lines which are more or less broken and often branched or forked; these are scarcely visible without a lens. Epidermis thin, brownish yellow, usually mostly peeled off in dry speci- mens, but on the anterior end, in front of the radial groove, it is a little more persistent. In the left valve the anterior tooth is strong and prominent, with the proximal end the thicker, more elevated, rounded or clavate; distally it is curved and diverges considerbly from the antero-dorsal margin; between this tooth and the resilial pit, there is a small central tooth only a little elevated. The resilial pit is directed obliquely backward, and its cavity is obliquely upturned, forming a distinct excavation on the inner surface of the posterior tooth with which it is confluent; this posterior tooth is simply a dis- tinctly thickened and slightly elevated portion of the postero-dorsal margin, which forms the boundary of the ligamental area, it is often, but not always, opposite the position of the resilial pit. In the right valve the anterior tooth is a slightly raised, somewhat curved ridge^on the inner .surface of the shell, running to the middle of the anterior muscular scar; the central tooth is shorter and much more elevated, most prominent at its inner end; between these two teeth there is an additional, slightly raised, tooth-like ridge; the posterior tooth is about as long as the anterior, and much more elevated and stouter, its distal end being the thicker and higher, with a distinct angular summit; the oblique resilial pit is excavated out of its anterior surface. The ossicle is somewhat elongated, curved or crescent shaped. The interior of the shell is only slightly lustrous and shows but little iridescence. Length of one of the largest specimens, 19 mm.; height, 11 mm.; thickness, about 3 mm. Found in considerable numbers at twenty-three stations, north of Cape Cod, off Stellwagens Bank, and off Chatham, in 10 to 43 fathoms, 18712-1881. This species, which is common in the vicinity of Cape Cod, has prob- ably been confounded, hitherto, with C. trilineata Say, and C. goul- diaiia Dall. From the latter, which occurs abundantly in the same NO. 1139. DEEP-WATER MOLLUSC A— VEKRILL AND BUSH. 821 region, it differs in its much smaller size, much less iridescent interior, straighter postero-dorsal margin, less upturned rostrum, and narrow, or more accumulate, posterior halt' of the shell. The hinge also differs in several respects. KENNERLIA BREVIS, new species. (Plate LXXXVIII, fijys. 7, a, b.) Kennerlia glacialis VEKRILL, Notice of Recent Add. to Mar. Invert., Pt. 2, Proc. IT. S. Nat. Mus., Ill, p. 397, 1881; Traus. Couii. Acad., V, p. 567, 1882; VI, p. 277, 1884.— BALL, Bull. U. S. Nat. Mus.. No. 37. p. 68, 1889 (in part). Shell short, sublimate, very inequilateral, obtuse at both ends, slightly narrowed anteriorly. The autero-dorsal margin is short and slopes rather rapidly to the anterior end, where it forms an obtuse angle with the ventral margin which is broadly and nearly evenly rounded, and passes into the rounded posterior margin without angulation, but some- times witli a slightly sinuous curve below; there is also, sometimes, a very slight sinuosity anteriorly; the postero-dorsal margin is nearly straight. The left valve is rather convex, moderately thick, nearly smooth, with a distinct, narrow radial ridge running from the beak to the posterior end. The right valve is smaller, concave or nearly flat, lunate, widest behind the middle, regularly curved ventrally or faintly sinuate anteriorly; its surface is marked by lines of growth and crossed by radial grooves, of which about ten are very distinct, while many others, much finer, can be seen with a lens. In the right valve the hinge consists of two small, divergent teeth, both of which are directed posteriorly. The rather thin, elongated posterior one, in a profile view, is obtusely triangular, its highest point distal to the middle; the slender resilium is attached to this, nearly the whole length of its anterior side, and carries a long, narrow ossicle. The cardinal tooth directly under the beak, is much shorter and somewhat thicker, with its highest point near the proximal end which is close to the dorsal margin. There is also a slightly elevated, rather indistinct, anterior sub marginal ridge, parallel with the margin, which supports a slender ligamental groove. In the left valve the hinge consists of a submarginal, thickened, blunt anterior tooth, running forward subparallel with the margin, and a posterior submarginal thickening or ridge having the resilium attached to its anterior side; the V-shaped space is relatively very wide and is not divided by any distinct intermediate ridges, such as occur in typical Pumlom. The resilium appears to be simple, not divided in a V-shaped form as in the latter genus. Length of one of the largest specimens, 11.5 mm.; height, 7 mm.; thickness, 3 mm. Found in small numbers at about ten stations between N. lat. 40° 15' 30", W. long. 70° 27', and X. lat, 85° 10' 40", W. long. 75° 6' 10", in 58 to 100 fathoms, 1880-1880. This species, which is southern in its range, is closely related to the 822 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. northern K. glacialis (Leach) with which it was formerly identified. It is a smaller, shorter, and more inflated species, with a shorter and more sloping antero-dorsal margin and a more evenly curved ventral margin, without the distinct antero-veutral indentation seen in that species. The convex valve has a distinct, posterior radial ridge which is faint or lacking in K. ///arm//*. There are also differences in the hinge, in the right valve of the latter the teeth are more divergent, etc. Doctor Carpenter, who established the group Kennerlia, defined it as differing from typical Pandora in having an ossicle on the cartilage or resilium, and radial grooves on the right valve. Perhaps the simple linear form of the resilium in Kennerlia and its forked or V-shaped form in true Pandora (type P. rostata Lamarck) may be of more impor- tance. The intermediate ridge in the left valve of Pandora fits between the two divisions of the V-shaped resilium. There is also in Kennerlia a small, buttress-like projection within the margin, under the beak, which supports an inward projecting portion of the ligament, darker in color than the resilium. Family PERIPLOMIDJE. PERIPLOMA AFFINIS, new species. (Plate LXXXVII, fig. 4.) Shell thin, fragile, broad ovate, with the beaks behind the middle and with a short, narrowed posterior end. The antero-dorsal margin is broadly convex: anterior end nearly evenly rounded, but slightly produced in the middle; ventral margin evenly convex to the base of the rostral region where it becomes slightly incurved; posterior end much narrowed, compressed and produced into a short, blunt rostrum with the edges gaping slightly at the end; postero-dorsal margin nearly straight, sloping rapidly to the angle of the rostrum ; a faint diagonal ridge extends to the lower rostral angle, posterior to which the shell is smoother than elsewhere and marked with several faint, radial riblets. The general surface is covered with irregular, uneven and often rather faint, concentric undulations, separated by rather wide concave intervals which, like the elevations, are covered by thin, elevated lines of growth. The undulations are most regular on the umbos and become less distinct and more irregular toward the margin and anteriorly, and show by transparency on the interior of the shell. The chondrophore is small, but very prominent, spoon-shaped, narrow at the base and expanded distally, with a nearly round resilial pit. The ossicle is well developed, bent into a crescent shape, and so formed as to fit into the small rounded notch in the shell margin in front of the choudrophores. A somewhat elevated submarginal ridge extends forward from the notch and serves to support the thin ligament; a similar but less prominent ridge extends backward from the choudro- phores and defines a distinct ligamental groove. No.n:t9. DKEI'-WATKIi MOI.LUSCA—VERRILL AM) HUSH. S23 Length of the largest specimens, 1.'! mm.; height, 10 nun.; breadth, 8 mm. Three specimens were found at three stations, off Marthas Vineyard, in 100 to 115 fathoms, 1880-81. I'll is species resembles /'. nndulata in sculpture, but the latter is narrower and longer in form, and has a more decidedly longer rostrum; its chrondrophore is shorter and broader, and not so distinctly spoon- shaped distally, while the marginal notch in front of it is relatively much smaller. PERIPLOMA UNDULATA Yen-ill. (I'lutes LXXIX, fig. 1; LXXXVII, fig. 5.) Pmploma nndiiht/a VERRILL, Trans. Conn. Acacl., VI, pp. 433, 448, 1885. A few specimens were found at six stations between N. hit. 39° 9', AY. long. 73° 3' 15", and N. hit. 36° 42', W. long. 74° 30', in 541 to 810 fathoms, 1884-1887. Family LIMID^E. LIMATULA REGULARIS, new species. Shell small, thin, nearly equilateral, much higher than long, with the hinge line straight and rather long. Umbos and median part of the shell swollen. Beaks rather prominent, directly incurved. Liga- ment al area relatively large, elongated, diamond-shaped, with the pointed end extending nearly to the angles of the hinge-margin, with a central, more sunken, short, rhomboidal ligament-pit which, on a separate valve, forms nearly an equilateral triangle. The anterior and posterior ends are nearly equally curved, a little convex, but slightly narrowed where they join the hinge-margin and form a distinct obtuse angle; on one side, supposed to be anterior, below the angle the mar- gin is slightly incurved for a short distance, making this angle less obtuse than the other. The ventral margin is nearly evenly rounded, forming nearly the segment of a circle. The surface is covered with small, elevated, radial ridges separated by concave grooves of greater breadth; in the middle of the shell between ten and twelve of the ridges are distinctly higher and thicker; on each side their size dimin- ishes outwardly, so that near the angles of the hinge they become nearly or quite obsolete, the last ones being mere raised, microscopic threads; in some cases smaller ones alternate with the larger ones, so that the total number can not be definitely determined, but fifty or more can often be counted. There is often no very evident median external sulcus, such as occurs in several related species, but the two or three central radii are often, but not always, distinctly larger than the rest. The radii are crossed by very tine lines of growth not suffi- ciently strong to render them at all nodulose. The inner margin is 824 PROCEEDINGS OF THE NATIONAL MUSEUM. voi.xx. distinctly creimlated along the prominent ventral edge, tbe crenula- tions corresponding to tbe external grooves and ridges, but at the ends it is smooth. There is often a distinct, median internal groove, extend- ing from near the beak to the middle of the ventral margin, bordered on each side by a distinct raised ridge, sometimes having an additional groove on their outer sides. The hinge-margin is rather thin, nearly straight, and a little excavated or incurved along the ligamental pit; on each side and considerably within the margin there is a small triangular buttress or shelf-like process extending to the anterior and posterior margins as in the allied species, but rather larger than usual. Length of one of the largest species, 6 mm. ; height, 9.0 mm. ; thick- ness, about 5 mm.; length of hinge-margin, 3.6 mm. A number of separate valves, station 2265, N. lat. 37° 7' 40", W. long. 74° 35' 40", in 70 fathoms, 1884. This species is allied to Limatula subonata (Jeffreys) Smith,1 which is distinguished by its shorter hinge-margin, more contracted form, with stronger and higher radial ribs and well-marked median sulcus. It also lacks the incurvature of the margins below the angles of the hinge. LIMATULA NODULOSA, new species. Shell small, nearly equilateral, vertically ovate, narrowed above, with a comparatively short, straight, hinge-margin. Umbos prominent, a little compressed. Beaks small, a little prominent, directly incurved. Surface covered with radial ribs which are very fine and even on the anterior and posterior ends, but in the middle region, become much stronger and are rendered nodulose by strongly marked, raised, concen- tric lines and grooves. The two median ones are much stronger than the others and are separated by a distinct median sulcus. The inner surface is marked by radial ridges and grooves of which the median ones are much the stronger; inner margin crenulated ventrally by the ends of the ribs and grooves. Ligamental area diamond shape with a small, short, rhomboidal ligament-pit in the middle. The hinge-margin forms an obtuse angle at each end, the two nearly or quite equal; internal buttress well developed with the inner margin regularly curved and continuous across the middle, so as to thicken the hinge in this part. Length, 4.5 mm.; height, 7 mm.; thickness, about 4 mm.; length of the hinge-margin, 2 mm. A single valve, among Foraminifera, at station 2385, 1ST. lat. 28° 51', W. long. 88° 18', in 730 fathoms, 1885. This species agrees with L. subovata (Jeffreys) Smith almost com- pletely in size and form, but differs very decidedly in the strong, nodu lose, radial ribs which cover the middle portion of the shell. 1 Limci'a subovata Verrill, Notice of Keceiit Add. to Mar. Invert., Ft. 2, Proc. U. S. Nat. Mus., Ill, p. 402, 1881. NO. 1139. DEEP-WATER MOLLUSCA-VEREILL AND BUSH. 825 LIMATULA HYALINA, new species. Shell small, thin, translucent, vertically ovate, somewhat oblique, and produced postero-ventrally. Hinge- line straight, rather short, forming a well-marked angle at each end owing to the outline of each margin becoming somewhat concave below. Beaks small, acute, in- curved. Umbos prominent, smooth, beyond which the shell is covered with numerous, clearly defined, rather sharp radial ridges, separated by wider concave intervals; from twenty to twenty-five of the radii can be easily counted ; toward the posterior margin they become faint and indistinct, while the extreme margin, on both sides, is smooth. The anterior margin is broadly rounded and slopes backward below the middle; the posterior margin is nearly straight or even a little incurved in its upper half, but becomes slightly convex below; the ventral mar- gin is evenly rounded and the edge is slightly scalloped by the radial ribs and furrows. There is no distinct median sulcus or larger ribs. The ligameutal area is rather short and broad with a relatively large and thick central ligament which occupies a distinctly excavated pit in the hinge-margin. Length of one of the largest specimens, 4.5 rnni. ; height, 7.5 mm. ; thickness, 3 mm. A number of live specimens, among Forarniuifera, stations 2307 to 2374, N. lat. 29° +, W. long. 85° +, in 25 to 27 fathoms, 1885. This species somewhat resembles Limatula confnsa Smith, which was also taken in the north Atlantic and West Indian areas, in 450 to 1,450 fathoms. Our species is, however, more compressed and more oblique, and the radial ribs do not extend to the extreme margins as in the lat- ter. The hinge-margin is also relatively shorter and the ligameutal area larger, so that the beaks are more separated. Family PECTINID.E. In this family the classification adopted is that proposed by the senior author in a recent paper on the group.1 We give here a brief abstract of the existing genera and subgenera therein described. For fuller discussions of the characters and interrelations of these groups and illustrations of typical species of most of them, reference should be had to that article. In the following synopsis the generic groups are arranged in chrono- logical order, without regard to their zoological affinities. 1 "A study of the family Pcctinida-, with a revision of the Genera and Subgenera." By A. E. Yen-ill, Trans. Coun. Acad. of Sciences, X, pp. 43-95 (six plates), July, 1897. 82G pR(i<-i-:i-:inxas OF THE NATIONAL MUSEUM. VOL.XX. PECTEN M tiller, 1776. Pecten (1st section) KLEIN, 1753 + Vola. Pccten MULLER, Prod. Zool. Daii., 1776 (pars).— DAC'OSTA, 1778. — BOLTEX, 1798 (restricted).— CUVIER, 1798.— LAMARCK, Syst., 1801.— VERRILL, Trans. Conn. Acad., , pp. 56, 89, 91, 1897. .fatih-ii SCHUMACHER, 1817. — BALL, 1886 (pars). — FISCHER, 1887. I'ola H. :ind A. ADAMS ("after KLEIN), 1858. — STOLICZKA, Mem. Geolog. Survey <»(' India, Cretaceous Pelecypod Fauna, III, p. 426, 1871. — ZITTEL, 1X81. To/a -f- Ja-nlra CIIENU, 1862. Type. — I'ecten nuiximns (Linnaeus). Since Bolten, in 1798, definitely restricted the name Pecten to this group, his restriction has precedence over that of Schumacher. The shells are generally large and heavy, and the valves are very unequal, even when very young. The right valve is strongly convex with a large and much incurved umbo and beak, while the left valve is llat or even concave. It is usually smaller than the right, and shuts closely inside of its scalloped margin, and its umbo is nearly or quite obsolete. The auricles are of moderate size and not oblique, and in the right valve they are strongly convex or excurved in the middle. This valve has a sinuous, excurved byssal notch, with obsolete pectinidial teeth. The surface of both valves has strong radial ribs interlocking at the margin. Internally there are angular, thickened, and fluted radial ribs opposite the external grooves; these ribs become more prominent and bicarinate or fluted near the margins. AMUSIUM Bolten, 1798. Amusiitm BOLTEN, 1798. — MUHLFELDT, 1811. — SCHUIIACHER, 1817.— WOODWARD, I860.— DALL, 1886.— VERRILL, Trans. Conn. Acad., X, pp. 57, 90, 92, 1897. Amiissium H. and A. ADAMS, 1858 (pars). — STOLICZKA, Mem. Geolog. Survey of India, Cretaceous Pelecypod Fauna, III, p. 426, 1871. — FISCHER, 1887.— ZITTEL, 1881. Pleiironectia SWAIN, 1840.— CIIENU, 1862. Type. — Amusium pleuronectes (Linnreus). In this very distinct genus the shell is round, thin, nearly smooth, and strongly compressed. The surface is often polished, sometimes lightly radially striated, never strongly ribbed. The margins are sim- ple and thin. The valves may be a little unequal in convexity and usually differ in color and somewhat in sculpture. The valves come together ven trally, but usually gape at both ends. The auricles are small, symmetrical, nearly equilateral, often with lateral crune; the byssal notch is small or absent, pectinidial teeth nearly or quite abor- tive. The adult probably has no byssus. Hinge-plate simple. Interior of valves strengthened by a number of raised divergent ribs, or line, independent of any external sculpture. NO. 1139. i>i:i:r-w.iTEi; MOLLUSC. i—rEi; HILL .L\I> r.rxn. 827 CHLAMYS Bolten, 1798. f'hlitiiii/s lioi.TKN, Mus. Holt.. 1st f, 17!»S, restricted. — FISCHER. 1887 i liars). SrinMACiiKK, 1817 (restricted). — VERRILL, Trans. Conn. Acad., X, pp. 58, 89, 91, 1897. /Hirn" and Clilum/i* i>t, M!>, l»l. 1897. Type. — Lyropecten noflosns (Linnaeus). Shell large and strong, corrugated, with large, fluted, and usually nodose, primary radial ribs, which do not increase in number, and with coarsely scalloped margins. Valves somewhat unequal. Auri cles of medium size, unequal. Hinge plate with several, usually three, oblique, divergent ribs on each end. This is one of the best denned groups, and may be regarded as of generic value. It is allied to Pallium. PROPEAMUSIUM Gregorio, 1883. I'rojH'amiisiinn (subgenus) DALL, Bull. Mas. Comp. Zool., XII, p. 210, 1886.— FISCHER, 18X7. — (genus) VKKUILL, Trans. Conn. Acad., X, pp. 61, 90, 92, pi. xx, figs. 5-9, 1897. Type. — Propeamusium inequisculpta (Tiberi) = Propeamusium fenes- tratiim (Forbes). This group is allied to Amnsium. It includes small, mostly deep-sea species, with thin, rounded shells, having the valves unequal in size and sculpture; the lower and flatter one is concentrically grooved, and usually turns up at the thin margin to meet the upper valve, as in Cyclo- pecten. The upper valve may be cancellated or radially sculptured. When full grown there are several well-formed, raised, internal ribs; these may be absent in the young. This division differs from Amusmm in the sculpture of the valves and in having the auricles and byssal notch well developed. The species closely resemble those of Cyclopecten ; the only obvious difference in the shells is in the presence of internal ribs. PALLIOLUM Monterosato, 1884. I'nllinliun (submenus or section) VKKKILL, Trans. Conn. Acad., X, pp. 65,90,91, pi. xvm, tigs. 6-1-1,1897. Types cited. —Palliolwm testce (Bivona) and Palliolum rilrnun- (Chem- nitz). This group is separated from Pseudamusium H. and A. Adams, and can scarcely be distinguished from Camptonectes by any known char- acters. The two species named by its author as types agree in having thin, rounded, nearly equivalved shells, with the posterior auricle poorly developed, and with tine camptonectes sculpture on both valves, with small radial riblets, and usually with rows of small scales. The mar- gins are plain and come evenly together, without flattening. 830 i'ffocEEHfycfi OF THE NATIONAL MUSEUM. VOL.XX. JEQTJIPECTEN Fischer, 1887. .I'.i/iii/ii'i-li'ii (suligemis of C hlamtjn) VKRRILL, Trans. Conn. Acad., X, pp. 59,67,89, 91. pi. xvi, figs. 6-11 ; pi. xx, figs. 1-3, 6, 6a, 1897. Type. — JIVquipecten opercula rix ( Linn;ijus). Shell broadly rounded, with the valves nearly equal and symmetrical. Auricles well-formed, angular; byssal notch well-developed. The sculp- ture consists of a moderate number of large and nearly equal primary radial ribs, which increase in size, but are not much increased in num- ber with age, by the interpolation of new ones. Internal ribs or flutings correspond to external grooves, but each one is bicarinate or double, especially near the margins. Hinge-plate with one or two slightly divergent ribs at each end, often crossed by strong transverse incisions. Pectinidial teeth abortive in the type, but present in most species. The foot of the type species is subcylindrical, well-developed, with a byssal fissure and a terminal, deeply bilobed u scooped-shaped " disk, which can be expanded. In JE. irradians l the foot has a similar structure, but the terminal disk appears to be smaller. PECTINELLA Verrill, 1897. Pet-lhifUn VERRILL, Trans. Conn. A<-ad.. X. pp. 6S. !»<). !)2, 1897. Type. — J'ectiitelhi sit/xhci (Dall). Shell small, thin, swollen, nearly smooth, with convex and slightly unequal valves. Auricles very unequal, oblique, the anterior larger, with a deep byssal notch in the right valve, but without pectinidial teeth ; posterior auricle small. The surface is smooth except for fine lines of growth. Camptonectes sculpture is not present. The texture is not hyaline. The only known species is I'ectinella sigsbei (Dall)2 which was taken by the Blake Expedition in the West Indies, in 158 fathoms. LISSOPECTEN Verrill, 1897. l.ixm>l>t'<-tcn ("Mil>»-riius of Chlaiityx) VEKRILL, Trans. Conn. Acad.. X, pp. (is, 90, 91, 1897. Ti/pe. — Lissopecten hyalinus (Poli). Shell slightly inequivalve, broadly rounded, not oblique, thin, trans- lucent, nearly smooth. The external sculpture consists of faint, nearly obsolete radial ridges and obscure riblets, but one or both auricles may have a more or less cancellated sculpture. The interior sculpture con- sists of very distinct, simple, raised ribs. Auricles angular, well-devel- oped. Byssal notch deep. Pectinidial teeth prominent. Margin not scalloped, nearly plain and simple. 1 Trans. Conn. Acad., X, pi. xx, lii;-. ti. 2 Bull. Mus. Conip. Zool., XII, p. 223, pi. iv, tig. 2, 1886. M0.n::n. /)/•;/•:/»- JFJ TV?/,' UOLLUSCA— VEHHI1.L J.V/> Hl'SIf. 831 Although this group agrees with Ainu. viinn, in having internal ribs without corresponding external grooves, it seems to be allied rather to Cltltnnt/N. It may be regarded as a division of the latter in which the external radial ribs have degenerated. LEPTOPECTEN Verrill, 1897 !.i'l>ti>i>«'tni (sul)»-ciiiis of Cli lam i/x) VKKUILI., Trans. Conn. Ai-:iil.. X, j»j>. ('>!», S!i. Ill, IS! IT. n im.nuitiiiii-rix i. Conrad). Shell thin, translucent, oblique, broadly rounded, with strong, rounded radial ridges or folds, like corrugations, which appear in reverse on the interior surface. The internal ribs are not angulatedby a deposit of shell, nor distinctly thickened. Margin with broad scal- lops. The exterior surface is covered with tine divergent camptonectes sculpture, both on the ribs and intervals. The ribs do not increase in number with age but become broader and more flattened. Auricles large and broad, thin, corrugated. Byssal notch large and deep. Pec- tinidial teeth prominent. Hinge-plate thin and but little differentiated. Cardinal ridge thin and small, close to the ligament, crossed by fine incisions. PLACOPECTEN Yen-ill, 1897. rti>«-i1. \YIII. tins. 1-7: i)l. xx, tigs. 7,8, 8a; pi. xxi, figs. l-2a, Type. — ridrojicctcii cl intoning (Say). Shell large, compressed, broadly rounded, rather thin, with simple sharp edges, meeting evenly ventrally, but gaping considerably at both ends, especially when adult. Valves only slightly unequal in form, the right one being a little flatter, but they differ in color and somewhat in sculpture, the right one being smoother and paler. Both have tine radial lines or riblets, and they have vermiculated divergent riblets when young. Auricles small, symmetrical, nearly equal. Byssal notch small, simple. Pectinidial teeth generally obsolete, except when young. No internal ribs. Inner surface often with more or less pearly luster and a crystalline structure. Hinge-plate with two feeble. slightly divergent ribs on each end, crossed by fine transverse inci- sions. The foot ' is well developed, oblique, slightly narrowed distally and enlarged at the end, where it is divided into two lobes by a rather deep, oblique, longitudinal fissure, so that the lobes can be spread apart or closed at will, thus resembling somewhat the foot of Le BUSH. 833 pectin idial teeth obsolete. The shell has a prismatic structure. Inter- nal lira1 and auricular crane well-developed. The structure of the animal was described by Mr. Ball as very dif- ferent from that of typical Ammium. According to his description it has a single pair of gills, with long, simple, separate filaments. The foot is slender, with a byssal groove; the end is much enlarged, with an oblique, expanded, concave terminal disk, striated within. Xo labial palpi. Ocelli without pigment. A specimen, well preserved in alcohol, examined by us, had two ro\vs of long, slender, reflected gill-filaments, as usual in this family. They were attached to a broad basal membrane, with a free, lanceolate, pos- terior portion. Two pairs of broad, foliaceous, incurved palpi, tinged with dark brown. Those of the anterior pair are united into a hood over the mouth; the others are smaller, curved inward, somewhat lan- ceolate at the tips. No ocelli could be found. The pallial tentacles are all in one row, numerous, of various sizes; from four to six large ones, with as many alternating small ones, correspond to each larger undu- lation or scallop of the mantle-margin. No guard-tentacles. Muscular pallial border is broad, thickened, radially striated, forming a ridge, as preserved, but not tentaculated. Free portion of rectum long and slender. A synopsis of the Pectiuida? was recently published by Dr. Frederico Sacco.1 He recognized three genera : Chlamys, A-HIHNX/HID, and Pecten, with the same types given by Verrill. Under Chlamys he gives nine subgeuera. Of these, four — Chlamys (restricted), Hinnites, JEquipecten, and Palllo- lum — correspond with the groups of the same name given by Verrill; Fdlpcs Locard (type, pcsfelis L.), Peplum Buccjuoy, Dant/enberg, and Dollfus, 1889 (type, inflexum Poll), Macrochalinis Sacco, 1897 (type, latix- sinid Brocchi), Flexopecten Sacco, 1897 (typev//e.r»o,s'«sPoli), Lissochlamis Sacco, 1897 (type, excisti Bronn), are additional to those given by Verrill. Under Amussium he has, besides the typical group, four subgenera. Of these, t\vo are new — Parvamussium Sacco, 1897 (type, duodecimlamel- latum Bronn), Variamussium Sacco, 1897 (type, cancellatum Schmidt). The two others are Propeamussium and Pseudamussium. The three ue\v subgenera of Pecten are Amiixsiopecten Sacco, 1897 (type, bnrdiyalensis Lamarck); Oopecten Sacco, 1897 (type, rotinnltdHH Lamarck); and FlaheUipecten Sacco, 1897 (type, fldbelliformis Brocchi). 1 ISolletino del Mus. Zool. ed Anat. Comp., Univ. di Torino, XII, p. 101. It was apparently issued at about the same time as that by Professor Verrill, here abstracted. Proc. N. M. vol. xx 53 834 rnoc'.KEDiNos OF THE NATIONAL MUSEUM. VOL.XX. CHLAMYS BENEDICTI Verrill and Bush. (Plate LXXXIV, ligs. 1, 2.) (•hlnmi/s ln'Hi- f. /,r.vr./_; •[•:/; HILL AND nrsir. 835 It is probable, however, that it grows to a much larger si/e than any of the specimens obtained. It is named in honor of Mr. James B. Benedict, for several year^ zoologist in charge on the steamer Albatross, through whose; care and great interest so many small species were brought to light. CHLAMYS COSTELLATA Verrill and Bush. (Plato LXXXVIJ lig. 6.) Chlamijs costellata VERRILL and BUSH, iu VERIULL, Trans. Conn. Acail., X, pp. 75, 91, 1897. Shell small, thin, translucent, bluish white, covered on both valves with continuous, elevated and somewhat thickened, well-separated, radiating riblets, of which there are more than thirty in the left valve of the largest example. Length of the shell considerably less than its height. Dorsal hinge-margin elongated, especially on the anterior end. In the right valve the anterior auricle is considerably elongated, obtusely rounded or subtruncated at the end, with a wide, angular byssal notch beneath it, having two or three pectinidial teeth; it has a broad, smooth, angular area next the body of the shell, above which there are three well-marked, angular, radial ridges, separated by wider concave interspaces; the posterior auricle is small, triangular, the outer corner forming a little more than a right angle, and the posterior mar- gin nearly straight, without any distinct notch. The dorsal margins of the body of the shell are nearly straight and diverge at less than a right angle; the ventral margin is pretty evenly rounded, a little produced in the middle. The beak is small, acute, appressed, and does not project beyond the margin. The radial ribs are very distinct, clean cut, thickened, rounded at the summit, separated by nearly smooth intervals, two or three times as broad as the ribs themselves; the ribs increase regularly in width from near the urnbo to the margin; a few intermediate ridges commence near the margin. The left valve is badly broken ; it is, however, somewhat more convex than the other, and the radial ribs are crossed by numerous concentric striatious giving them a finely crenulated or beaded appearance; the anterior auricle is broad, triangular, the outer end slightly rounded, with a slight incurved notch below; it is crossed by about six small, radial ribs, similar to those on the body of the shell; raised lines of growth also occur at irregular intervals. Inner surface smooth and lustrous, showing the grooves corresponding to the external ribs and also a very distinct microscopic structure, but it is destitute of radial lira1. Internally, the hinge margin is thin and narrow, with a sharply impressed, subinar- ginal groove on each side; the resilial pit is excavated in the margin of the hinge itself: the anterior auricle has internal grooves correspond- ing to the external ribs. Length of the largest specimen, <> mm.; height, G.a mm. Three live specimens, at two stations, off the Grand Banks, in 07 to 72 fathoms, 1885-86. 836 mocKEiuxas OF THE NATIONAL MUSEUM. HYALOPECTEN DJLECTUS Verrill and Bush. (Plate XCVII, fig. 9.) Hyalopecten dilectus YEKRILL and BUSH, iu VERKILL, Trans. Conn. Acad., X, pp. 80, 92, 1897. Shell small, thin, fragile, strongly imdulated, slightly oblique, with the ventral margin broadly rounded, dorsal margin straight. In the right valve the anterior auricle is rather narrow, elongated, with a deep angular notch beneath; the posterior auricle is shorter, with a prominent dorsal angle which is less than a right angle, owing to the emargination of the posterior end. In the left valve the anterior auri- cle is broad, with its posterior end nearly rectilinear, and forms a right angle with the dorsal margin; the posterior auricle has a slightly prominent dorsal angle and posterior emargination as in the right valve. The beaks are a little prominent and project somewhat above the dor- sal margin, more in the upper or left valve. The surface in both valves is covered with broad and rather regular undulations, which are most prominent in the left valve, and are crossed by regular, well-spaced, thin, raised, radial lines, which become fine and more crowded at the ends of the valve; they are nearly obsolete in the right valve, being represented by microscopic striae In both valves the anterior auricle is marked by several fine, rough, radial ridges which are stronger and more numerous iu the left valve. The interior is strongly undulated, and the left valve is marked by distinct, radial grooves, liesilium small, central. Color yellow, or dirty white. Length, 8 mm. ; height, the same. One live, imperfect specimen (No. 52539), station 2570, off Marthas Vineyard, in 1,813 fathoms, 1885. This species is closely allied to Hyalopecten fraailis (Jeffreys) and resembles very nearly his figure,1 which probably represents a species distinct from the original type described by him, and may be identical with our shell. The latter differs decidedly from the original descrip- tion of H. fragilis. Moreover, we have obtained from several stations a shell of similar size which appears to be the true fragilin,- as it agrees closely with the description. Hyalopecten pudicus (Smith) from east of Marion Island, in 1,375 fathoms, is a closely related species, as is also Hyalopecten -undatus Verrill. These four species agree in having the valves thin and translucent and sculptured with distinct concentric undulations, while the radial sculpture does not form strong ribs. They seem to be related to the genus or subgenus Syncyclonema Meek, which was based on a creta- ceous species and has not hitherto been reported as still living. But the exact characters of the typical fossil species are not yet known. 1 Proc. Zoo]. Soc., London, pi. XLV, fig. 1, June, 1879. -The true Hyalopecten fragilis (Jeffreys) was taken at five stations between N. lat. 40° 6', W. long. 68° 1' 30", and N. lat. 35° 49' 30", W. long. 74° 34' 45", in 578 to 1,525 fathoms, 1883-1886. NO. 1139. DEEP-WATER MOLLUSC A— VERBILL .i\I> BUSH. 837 CAMPTONECTES GRCENLANDICA (Sowerby) Verrill. (Plate LXXXV, fig. 7.) Pecti'ii ijranlandicus So WERBY, Thesaurus Conchvliorum, Pt. II, p. 57, pi. xili, fig. 40, 1842.—HAM.KY, KYrrnt Shells, p. 274, 1842 to 1856.— JEFFREYS, Ann. and Mag. Nat. History, p. 231, 1877. I'ecteii uronliindicus G. O. SARS, Moll. Reg. Arct. Norvog., p. 23, pi. 2, tigs. 4, a-c, 1878. Pecleu fathoms, 1884. Although very small, this species seems to be adult. It is so distinct from all other species of our coast that a detailed comparison is unnec- essary. It resembles the young of /'. cUnton'iis more than any other native species, but a comparison of specimens of the same size shows marked differences. NO. 1139. DEEP-WATER MOLLUSCA—YEERILJ, J .VI) BUSH. S39 CYCLOPECTEN LEPTALEUS Verrill. (Plato LXXXV, fig. l.» Pecten hptaltus VERKILL, Trans. Conn. Acad.. V, pp. 232, 2S1, 1882; Kxpl. .lllxi- tross, Report U. S. Coin. Fish and Fisheries lor isx;j, ]t. 577, 1885.— DAI. i., Hull. Mus. Comp. /ool., XII, p. 221, 1886. 1'iinHlaiiutsiinii leptaleun DALL, Bull. U. S. Nat. Mus.. No. 37, p. 34, 1889. Ci/<'l<>i>c<-/<'ii lejtlttli'iti VKURILL, Trans. Conn. Acad., X, pp. 85, 92, 1897. Mr. Ball lias expressed a doubt as to this species being distinct from I'ecten iinbrifcr Loven, therefore a very much enlarged figure of the shell is here introduced for comparison. In addition to the published description, it should be stated that the concentric lines are somewhat thickened and elevated, even where thinnest, and that the beaded character is quite unlike anything found on C. -imbrifer, or allied species. The beads are closely arranged, elliptical in form, and most elevated at the center, the elevation being often greater than the diameter ; the summit is smooth and glassy, so that when viewed from above, under a lens, they often appear to have a cen- tral cavity. The radial lines are comparatively very thin and delicate, and not visible, except when considerably magnified. The beaks are more acute than in C. imbrifer, and the nucleus smaller and smoother. Two live specimens, station 2109, oft' Cape Hatteras, J^orth Carolina, in 142 fathoms, 1883. CYCLOPECTEN PUSTULOSUS Verrill. (Plate LXXXV. tigs. 5, (i. 10, 11.) Pecten pustulosns VERRILL, Amer. Jonrn. Science. V, p. 14, 1873; Trans. Conn. Acad., Ill, p. 50, 1871. 1'i'cten Itoskynsi var. pustulosus VERRILL, Trans. Conn. Acad., V, }i. 5M, pi. xui, ligs. 22, 22a, 1882 (not pi. XLIV, fig. 11). Not Pecten lioxki/n*i G. O. SAHS. Pecten pustidosns VERRILL, Trans. Conn. Acad., VI, p. 2(!1 (p. 281 in part), 1884; Kxpl. Albatross, Report U. »S. Com. Fish and Fisheries for 1883, p. 557 (in part), pi. xxxi, figs. 142a, 6, 1885. Pecten imbrifer DALL, Bull. Mus. Coinp. Zool., XII, p. 220 (in part), (not pi. iv, figs. 4,i, 4ft), 1886; Bull. U. S. Nat. Mus., No. 37, p. 34 (in part), pi. IAIV, ligs. 142«, I, 1889 (not pi. iv, figs. 4a, 4ft). Not Pecten inibrifer LOYKN. Cyclopvcten piistiilosus VF.KRILL Trans. Conn. Acad., X, pp. 70, 83, 92, pi. xix, figs. 3, 4, 1897. This species has been referred to Propeamusium lioski/nxi by Jef- freys, and to Pecten ( Cydopeeten } imbrifer by Ball. It never has the internal ribs, like the former, which it resembles in sculpture. From the latter, as originally described by Loveu, and redescribed and figured by Or. O. Sars, it differs especially in the character of the orna- mentation of the left valve. The Scandinavian form, according to these authors, has the vesicles much less crowded in each radial row and subconical and mucronate in form; while in ours they are usually 840 rilOCEEDINdS OF THE NATIONAL MUSEUM. VOL.XX. closely crowded, often even in contact in the radial rows, and in form either rounded or elliptical with the longest diameter in the direction of the concentric lines, with the summit evenly rounded, showing no tendency to the subconical or mucronate form. When perfect they resemble small blisters with the surface roughened or minutely granulose under the microscope; when broken or worn off, as frequently happens, the basal part remains in the form of a semicircular or semieliiptical, imbricated, arched scale, usually considerably ele- vated above the surface and connected by very delicate concentric raised lines. The surface of the anterior auricle of the left valve is roughened by close, elevated, concentric lines, and from four to six well-marked radiating ridges or ribs, upon which the concentric lines form regular elevated arched projections, often so crowded as to be imbricated; in some young examples, like the one figured, the concen- tric lines on the auricle are less crowded and only two or three of the radial ribs are developed ; in such examples the vesicles on the body of the shell are relatively fewer, larger, more rounded, and much less crowded in the radial series. Jn some specimens the posterior margin, below the auricle, is nearly smooth or marked only by the fine lines of growth, while in others, especially larger specimens, this region is cov- ered by rather sharp granules, some of which, toward the ventral margin, change to pointed scales arranged in crowded radial rows. The raised concentric lines on the right valve are generally more or less appressed and sometimes imbricated ; toward the ventral margin some of them show very fine microscopic creuulatious, which are much less distinct than on i-:i-:r-ir.iTKi; MOLLUSCA—ri:i;i:u.i, AND r.rsii. 841 covered with small, close, radial ribs and crowded concentric ridges; posterior auricle much smaller, with from one to three faint, radial ridges and many concentric, raised lines, and with its outer end form- ing less than a right angle, with a slight incurved notch below. In the right valve the anterior auricle has a similar radial sculpture and the byssal notch is rather deep and narrow. The dorsal lines of the body of the shell form rather less than a right angle; the ventral mar- gin forms nearly a semicircle with an obtuse angle where it meets the dorsal outline. limbos a little prominent; beaks small, acute, smooth, and projecting beyond the margin of the hinge. The surface of the left valve is covered with slightly raised concentric lines, which are interrupted or broken up by small arched scales which are sometimes semicircular, but more frequently somewhat angulated or V-shaped, and usually are separated by intervals about equal to their breadth; these scales vary in number, but are usually arranged in about forty radial rows, and increase regularly in si/e from the umbos, where they are replaced by thin, slightly raised, radial lines crossing the stronger, more elevated, concentric lines, but not rising into points. In some specimens the radial arrangement is scarcely discernible; the scales appear as irregularities in the concentric lines. The postero dorsal area below the auricle is nearly smooth, except for the line lines of growth, but sometimes shows minute granules. The right valve, which is smaller than the left, is covered by fine, thin, close, concentric, raised lines, which sometimes show microscopic striations. The ante- rior auricle is decussated by from six to eight, or more, small radial ridges, which are crossed by the raised, concentric lines; the latter rise into sharp scales at the dorsal margin; the small posterior auricle has finer concentric lines and only two or three faint, radial ridges. Comparatively few specimens, at three stations, between X. lat. 42° 45' 30", W: long. G2° 4r, and X. lat. 39° 53' 30", W. long. 71° 13' 30", in 121 to 312 fathoms, 1877-1885. C. Icermadecensis (Smith), from north of Kermadec Islands, in GOO fathoms, is a related species. PROPEAMUSIUM THALASSINUM (Ball) Verrill. (Platt- LXXXVII, fig. 6.) Amusaium fenestratum VERRILL, Trans. Conn. Acad., V, p. 582, 1882. .ImiiKshim sp. VEUKILL, Trans. Com. Acad., VI, pp. 261, 281, 1884. 1'i'cten ( Pseudamusium) tliala^sinus DALL, Bull. Mus. Comp. Zool., XII. p. 221. 1886; Bull. U. S. Nat. Mns., No. 37. p. 34, 1889. I'ntpeamnsinm thalassintim VERRILL, Trans. Conn. Acad., X, pp. 87, !>L'. pi. xix, figs. 5-7, 1897. Found at thirteen stations, between X. lat. 40° 5' 39", W. long. 70° 23' 52", and X. lat, 35° 42', W. long. 74° 54' 30", in 43 to 317 fathoms, 1880-1885. South to Barbados, in 22 to 317 fathoms.— Dall. 842 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. Family AECIDJE. BATHYARCA Kobelt. Type. — Bathyarca pectunculoides (Scacchi). Shell oblong, subovate, or rounded, rather thin, usually finely can- cellated, with hairy or scaly epidermis, more or less equilateral, fre- quently slightly inequivalved, with a slight byssal sinus. Byssus very small. Ligameiital area lanceolate, longer and narrower behind the beaks, with a sagittate posterior ligament. Ilinge-margin nearly straight, usually narrow and edentulous in the middle, with a series of small, oblique, striated and crenulated teeth on each end, the distal ones becoming larger and more oblique; those of the posterior series usually longer and more oblique, or divergent, than those in the anterior. The animal of 7>. pectunculoides var. grandis, preserved in alcohol, has the margin of the mantle plain without ocelli, with a well-developed muscular septum, posteriorly; the foot large and thick, geniculate, pointed posteriorly, with a strong byssal groove and a slender, solid, byssal stem; two pairs of rather small, long, lanceolate palpi; the rec- tum with a free terminal portion; two pairs of rather large gills, with the posterior end of the stem free for some distance, curved, and tapered to a point, and with the reflected portion of the filament of the same length as the direct; the filaments are very slender, delicate, and soft and but slightly attached to each other. This division, which is probably of generic value, includes a number of small and mostly deep-water species which have been variously placed by recent authors. Mr. E. A. Smith puts several of them in Scapliarca with a mark of doubt. Mr. Dall puts two allied species in the Jurassic genus Macrodon^ with which they do not seem to agree very closely, and mentions the affinity of others to Barbatia. The last group differs in the stout, rough shell, strongly gaping veu- trally for the large byssus, and in the character of the teeth and liga- ment. ScapTiarca has a thick, strongly ribbed, inequivalved shell, a firm byssus, and continuous, strong, lanceolate ligament. Macrodon has, on the posterior hinge-plate long, divergent lamella?, nearly paral- lel with the dorsal margin. We would refer the following species to Bathyarca. — B. pectuncu- 1 The two West Indian species described by Mr. Dall as Macrodon aspenda and M. sagrlnata, should, perhaps, form a separate genus, characterized by the few very oblique, sublamellar, posterior teeth and several smaller, nearly transverse anterior ones. It may be designated as Bentliarca, with Bvntharca aspertila as the type. These are closely related to one of the Eocene fossil species (Area adrersidcnlata), which Beshaycs placed in his group of " Cucullaires, ' but later writers (Conrad, isii'l, Fischer, and others) have taken his first species (Jieterodonla) of that group as the type of the genus "Cucullaria," which differs in having the anterior as well as the posterior teeth long and lamolliform ; hence we would associate Tertiary species like Bentharca adversidentata with the living deep-water forms. N...n:!9. />/?/:/•- (r. r/7-; /,- voLLUSCA—rERRiLL .ixi> /.T.V//. 843 loi(l<'n (Sracchi) audits varieties, grandisVerrillj FreHei Jeffreys, MylcH- trioHnli* Sars, <-rc>tnl'. f/ldcidliti (dray), Arctic America and Europe. />'. »'. ((In/Nxontm Verrill and Bush, off I >ela\vare Bay. 1>. }»-»j'inil. (/loiitrriilft (Dall), 11. polyci/nia (Dall), B. culebrcnsis (Smith), off West Indies. />'. iiucijitixcitlpla (Smith), B. plo-ocxwi (Smith), Atlantic and Pacific. B. inntata (Smith), Pacific. r>c)ii]i(u-ca ((Ni»'>-nla (Dall), and B. aayrhmta (Dall), are from the West Indies, in deep water. BATHYARCA ABYSSORUM, new species. (Plate LXXVI, %. It. . Shell small, short, well-rounded at both ends, swollen, inequilateral, slightly oblique, with a rather long1, straight hinge-margin. Tmbos large, swollen, prominent. Beaks prominent and curved strongly for- ward, situated considerably in front of the middle. Surface every- where covered with nearly equal, delicate, raised, radiating lines and small, rather even, raised lines of growth; these together produce a finely cancellated surface which, when fresh, is covered with a thin brownish-yellow epidermis forming small scale-like points at the inter- section of the lines; the surface is also marked with slight, irregular, concentric waves or undulations. The anterior margin is shorter than the posterior and forms an obtuse, rounded angle at its junction with the hinge-margin; the ven- tral margin is obliquely curved, most prominent behind the middle, where the curve forms nearly the segment of a circle; posterior margin is very broadly rounded and forms a distinct obtuse angle where it joins the dorsal margin. The ligamental area is lanceolate, mod- erately large, decidedly wider just in front of the beaks, becoming nar- row and pointed posteriorly. The dark ligamental patch is arrow- shaped, situated behind the beaks. The hinge margin is rather wide and strong, with a small, central edentulous space, mostly behind the beaks. The teeth, which are striated on the sides and creuulated on the edge, are equally and decidedly oblique in the two series; the prox- imal ones are small and the others increase in size and obliquity to near the end of the series, where one or two of the outermost are decidedly smaller and very oblique. In the largest specimen there are about six teeth in the anterior and eight in the posterior series. The inner surface shows faint radial grooves and ridges, much coarser than the external striie; there is also a fine, impressed line, with a finely creuulated edge close to the margin. Length of the largest specimen, 0 mm.; height, G.5 mm.; thickness, 5.5 mm.; length of the hinge margin, 3.5 mm. Three specimens were found at stations 2713 and 1'714, off Delaware Bay, in 1,825 to 1,859 fathoms, 1886. 844 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX This .species is allied to 71. f/lomcrula Ball. The latter differs in hav ing a, less rounded form with a longer hinge-margin, more definite terminal angles, and much more numerous and smaller teeth which are nearly continuous. In our specimens of B. ylomerula of corresponding size, there are about ten teeth in each series and they are about one-half as large. According to Mr. Dall's figures, the umbos of his species are larger than in the more northern form, but our specimens of his species have the umbos smaller than is indicated by his figures. The position of the beaks and form of the ligamental area is nearly the same in both species; but the latter appears to be a little wider in ours and the beaks are a trifle more oblique. The external sculpture is similar but the radial lines are decidedly stronger and less numerous in glomerula, and the sculpture is quite different in the two valves, while in ours there is no perceptible difference. B. inwquiscnlpta (Smith) is also a closely allied species which Mr. Dall considers identical with B. glome- rula. Mr. Smith's figures are quite different from those of Mr. Dall, and also from our West Indian specimens of the latter, and still more different from B. dbyssorum. BATHYARCA PROFUNDICOLA (Verrill). (Plate LXXVIII, fig. 2.) Area profundicola VERRILL, Trans. Coim. Acacl., VI, p. 439, pi. XLIV, figs. 23, 23a, 1885.— DALL, Bull. Mus. Comp. Zool., XII, p. 245, 1886. Macrodon profundicola DALL, Bull. U. S. Nat. Mus., No. 37, p. 42, pi. XLVI, figs. 23, 23a, 1889. A very few specimens, at three stations, between N. lat. 40° 29', W. long. OGo 4', and N. lat. .'57°, W. long. 71° 54', in 1,769 to 2,020 fathoms, 1884 and 1885. Also among Foramiuifera, station 2385, N. lat. 28° 51', W. long. 88° 18', in 730 fathoms. BATHYARCA ANOMALA, new species. (Plate LXXVII, fig. 8.) Shell small, oblong, inequilateral, much swollen with large prominent umbos, and pointed beaks, curved strongly forward and considerably separated, owing to the unusually wide, lanceolate, ligameutal area, which is covered behind the beaks with the remains of a dark thick- ened ligament. Dorsal margin straight for nearly its entire length; anterior and posterior ends broadly and about equally rounded, the posterior a little the more swollen below and longer; ventral margin broadly rounded, a little prominent in the middle, with a slight byssal indentation in front. Surface everywhere covered with fine, regular, raised, radiating lines which are decussated by finer lines of growth; the rather thin brown epidermis is scaly or chaffy on the radii, espe- cially toward the margins, where it forms minute points. Hinge-margin considerably thickened, increasing in strength toward the ends; in the No.1139. DEEr-WATEIl MOLLUSCA—VERBILL AND HUXH. 845 middle, where it is narrowest, it is nearly smooth and rounded, with only slight indications of one or two transverse teeth on each side; next these there are two or three somewhat oblique, slightly divergent, irregular, longitudinal, slightly striated and crenulated folds, separated distally by rather deep grooves nearly parallel with the inner margin. The inner edge of the ventral margin is thin and plain. Length, 8.5 mm.; height, 7 mm.; thickness, <> mm. One living specimen (No. 74081) was dredged by the 7>V/r//<> at station 52, oft' Cashes Ledge, in 27 fathoms, 1S74. As only a single specimen has been found, it is possible that it is but an abnormal variety, although it appears to have been healthy and well-grown in every respect. It is related to I> pectunculoides (Plate LXX VII, tig. (i), but differs remarkably in the character of the hinge, which has the transverse teeth scarcely discernible, and oblique, irreg- ular folds on the distal parts of the margin, and also in the greater width of the ligamental area. Family LIMOPSIIXK. LIMOPSIS SULCATA, new species. (Plates XCII, fig. 2; XCV, tig. 9; XCVI, lig. 1.) Shell very oblique (young specimens are less oblique and in some cases are more nearly circular), broad ovate, the posterior ventral mar- gin much produced and obtusely rounded; auricles only slightly devel- oped. The dorsal margin is short and straight, with a narrow, smooth area beneath the beaks; the anterior margin is subtruncate, or very obtusely rounded; the ventral margin is oblique, broadly rounded, forming an obtusely rounded angle with the posterior margin, which is strongly sloping and only a little convex. The umbos are small and somewhat prominent; the beaks small, pointed, and curved inward. The entire surface is covered with strongly marked, concentric grooves and prominent rounded, narrow ribs; the latter are crossed by numer- ous fine, radiating, incised striatious, which divide them into beadlike, or squarish, portions, which are most obvious on the middle and pos- terior parts and become very faint anteriorly. The hinge-margin is much thickened and bears a curved series of rather large, flattened teeth, of which about eight are situated in front of the beaks and about ten behind them; those nearest the center are small; the resilial pit extends upward to the beak in the form of a small triangular depression. The inner surface of the shell is marked by fine, radiating stria-; the margin is thickened and cut away near the edge; no crenulations have been observed in our specimens. Greatest length, 12 mm.; greatest height, 13 mm.: breadth, 6 mm. A number of separate valves, at about ten stations, between X. hit. 40° 8', W. long. 68° 45', and K lat. 37° 1' 4", W. long. 74° 35' 40", in 64 to 349 fathoms, 1880-1884. 846 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. LIMOPSIS MINUTA (Philippi). (Plates LXXV, fig. 1; LXXVIII, fig. 7.) //n>u>i>sis iniiiiilii, VKKRILL Trans. Conn. Acad., V, p. 576, 1882; VI, p. 280, 1884; Expl. Albatross, Report U. S. Com. Fish and Fisheries for 1883, p. 577, 1885.-- SMITH, E. A., Report Yoy. Challenger, Zool. Lamellibraucluata, XIII, p. 258, 1S85.— DAI.L. Bull. Mus. Coinp. Zool., XII, p. 236, 1886; Bull. U. S. Nat. Mas., No. 37, p.42, 1889.— BrsH, Ball. Mus. Corup. Zool., XXIII, p. 235, pi. i, fig. 8, 1893. — LOCARD, Campagne du Cauilan, Aunales de I'Universitc de Lyon, p. 198, 1896. A very common and abundant species, at eighty-two stations, between N. lat. 44° 7' 30", W. long. 57° 16' 45", and X. lat. 35° 49' 30", W. long. 74° 34' 45", in IK) to 2,2:>1 fathoms, 1880-1887. South to Barbados, in 30 to 2,221 fathoms.— Ball. LIMOPSIS AFFINIS Verrill. (Plate LXXV, fig. 2.) I.imi>i>ni.x itflinix VERRILL, Trans. Conn. Acad., VI, p. 442, 1885. Two live specimens, at station 2092, N. lat. 39° 58' 35", W. long. 71° 30", in 197 fathoms, 1883. LIMOPSIS PLANA Verrill. (Plate LXXV, fig. 5.) lAmopsis sp. (?) VERRILL, Trans. Conn. Acad., V, p. 280, 1884. Limopsix phuia VERRILL, Trans. Conn. Acad., VI, p. 441, 1882; Expl. Albatross, UN-port U. S, Cora. Fish and Fisheries for 1883, p. 577, 1885. l.iniopxis anriia, var. pi an a DALL, Bull. U. S. Nat. Mus., No. 37, p. 42, 1889. Li>n»i>xix pi ana BUSH, Bull. Mus. Coinp. Zool., XXIII, pp. 240, 244, pi. n, figs. 19, 20, 1893. Three live specimens and one valve, at two stations, between N. lat. 38° 22', W. long. 70° 17' 30", and N. lat. 37° 40' 30", W. long. 70° 37' 30", in 1,825 to 2,221 fathoms, 1883-1880. South to Dominica, West Indies, in 1,131 to 2,221 fathoms.— Ball. The, largest specimen, from station 2710, is 18.5 mm. long; 18.5 mm. high; hinge-margin, 11 mm. long; ligamental area, 3 mm. long. LIMOPSIS AURITA (Brocchi) Jeffreys. (Plate LXXV, fig. 3.) .' Area aurlta BROCCIII, Condi, foss. Subap., II, p. 485, pi. xi, fig. 9 (t. Jeffreys). Limopsls aurlta JEFFREYS, British Conch., II, p. 161, pi. iv, fig. 3, 1864 ; V, pi. xxx, fig. 1, 1869. — SMITH, E. A., Report Voy. Challenger, Zool., Lamellibranchiata, XIII, p. 257, 1885.— DALL, Bull. Mus. Coiup. Zo("d., XII, p. 237, 1886; Bull. IT. S. Nat. Mus., No. 37, p. 42, 1889. — LOCARD, Campague du Caudan, Anuales de rUnivrrsitr de Lyou, p. 197, 1896. Not. Ltmopsls (inrita, variety, VERRILL, Trans. Conn. Acad., VI, p. 440, 1885. One valve, among Foraminifera, station 2385, N. lat. 28° 51', W. long. 88° 18', in 730 fathoms. South to Grenada, in 21 to 1,582 fatlioins.- Dall. HO. 1139. DEi-:r-n:iTi-:if MOLLUSCA—\'I<:HI:ILL AXI> arsrr. 847 The northern specimens (/,. profit ml icola) formerly referred doubt- fully to this species prove to be distinct. The single specimen now iiicluded agrees \vell with a specimen of the fossil form from Europe. LIMOPSIS PROFUNDICOLA, new species. Plates LXXY, lig. 4; LXXXIII, lig. 4.) l.ini(>i>.iix (inritd, variety (?) VERRILL, Trans. Conn. Acad., VI, p. 440, 1885. Comparatively few specimens, at ten stations, between N. lat. 41° 7', W. long. ° 2(>' 30", and X. lat. 30° 47', W. long. 733 9' 30", in 1,525 to 1,859 fathoms, 1884-1886. Family MYTILIDJB. CRENELLA FRAGILIS Verrill. ( Plate LXXXIII, figs. 1, 2.) CreiK-llii fragiiis VERRILL, Trans. Conn. Acad., VI, p. 444, 18S5.— I )ALL, Bulk U. S. Nat. Mas., No. 37, p. 40, 1889. One valve and a fragment, station 2205, N. lat. :!7° 7' 40", W. long. 74° 35' 40", in 70 fathoms, 1884. GLOMID.K, new family. lihnnuni VF.RKILL and Busn, Amer. .louru. .Set., Ill, pp. 53, 5H, January, 1S!I7. Shell short, roundish at both ends. Hinge-plate with a row of trans- verse teeth each side of the middle. Ligament thick, elongated, attached for most of its length to the inner surface of the posterior hinge-plate and running forward in a narrow groove beneath the beaks, so that its anterior portion is external and its thickened pos- terior portion is partly internal. No pallial sinus. Animal not known. This group includes, so far as known, only the genus Glomus Jef- freys, which has been referred by several writers to the Arcida\ and by others to the Ledidae, from both of which it differs widely. Its rela- tions to the ISTnculida- are somewhat uncertain, owing to our ignorance of the soft parts. In the form and position of the ligament it differs entirety from all other genera of Nu.culid.ji? and Ledida1. A more mature consideration of this group, since the publication of our former article, leads us to consider it as a family distinct from Nuculidse. GLOMUS Jeffreys. (.rlomus J KFFKEY.J, Annals Mag. Xat. Hist., p. 433, November, 187C>. — VERRILL aiid I.rsn, Amer. Join n. Sri., Ill, pp.53, 59, January, 1897. Type. — Glomus nifaix Jeffreys. Shell thin, smooth, snbequilateral, rounded at both ends, with the beaks turned forward. No lunule or escutcheon. Hinge with two series of obliquely transverse teeth ; a small lateral tooth may be present. SIS /'/,• oc /•:/:/> rx< ; x or THE NATIONAL MTSEUM. VOL.XX. The following are described species : (i. n i fens Jeffreys, North Atlantic (Europe) and from off Marthas Vineyard south to off Kiodela Plata (America); G. jcffreysi Smith; G.*i>n]>l<'.r Smith, and G.inwquilateralis Smith, West Indies; CT. japon- icus Smith, off Japan. GLOMUS NITENS Jeffreys. (Plate XCVI1, figs. 1,2.) (llomns nitens JEFFREYS, Annals Mag. Nat. Hist., p. 433, November, 1876; Proc. Zot'il. Soc., London, p. 573, pi. XLV, fig. 5, June, 1879. — VERRILL, Trans. Conn. Arad.. VI, p. 231, 1884; Expl. Albatross, Report U. S. Coin. Fish and Fisheries for 1883, p. 576, 1885. — SMITH, E. A., Report Voy. Challenger, Zool., Lamelli- brauchiata. XIII, p. 248, 1885.— DALL, Bull. U. S. Nat. Mus., No. 37, p. 46, 1889.— VERRILL and BUSH, Amer. Jonru. Sci., Ill, p. 53, figs. 1, 2, January, 1897. The specimens which we refer to this species agree closely in size and form with Jeffreys's figures, but there is in both valves a small submar- ginal lateral tooth just beyond the posterior series of teeth, and in the right valve a similar but less prominent one just beyond the anterior series. These are not mentioned in Jeffreys's description. In the pos- terior series there are fewer teeth than in his figure and they have an acute, oblique, V shaped outline and are but little raised; in the ante- rior series there are four larger, oblique teeth which are not so dis- tinctly V-shaped, owing to their oblique position and because the sur- face of the hinge-plate is turned downward. The posterior ligament is strong, long, wedge-shaped, widest distally where it occupies most of the width of the hinge plate; the narrow prolongation runs forward under the beaks in a narrow groove. There is a thickened, edentulous space under the beaks, separating the two series of teeth, which has, when highly magnified, a very small, angular notch in the middle of its lower edge, which in our specimen is filled with what appears like the remains of a resilium; there is also a very minute, V-shaped notch in the external margin. The beaks turn forward. The pallial impres- sion is rather indistinct, but appears entire. Interior somewhat lus- trous, but not at all nacreous. Two imperfect specimens, at two stations, off Marthas Vineyard and off Delaware Bay, in 1,544 and 1,608 fathoms, 1883 and 1886. South to Rio de la Plata, in 294 to 1,900 fathoms.— Dall and Smith. REVIEW OF THE GENERA OF LEDID^E AND NUCULID.E OF THE ATLAN- TIC COAST OF THE UNITED STATES.1 These families are often united by modern inalacologists under a sin- gle family (Xuculidai), while others regard them as distinct. They are certainly closely related anatomically, as well as by the structure of the shell. Thus all the members of both families have a single pair of 1 An abstract of the portion of this article relating to these families was published in the Americau Jourual of Science, III, p. 51, January, 1897. NO. 1139. DEEP-WATER MOLLUSCA—VEEEILL AND BUSII. 849 simple "foliobranchiate" (or protobrancliiate) gills; two pairs of large labial palpi, the outer ones furnished with long extensile labial tenta- cles; a large muscular foot with an expanded, concave, terminal disk, adapted for rapid motions in jumping and swimming, as well as for creeping; and all have two series of transverse or oblique teeth on the hinge-margin. The peculiar structures of foot and gills appear together elsewhere only in the family Solemyida-, which is evidently a related group, though it lacks hinge-teeth and has a very different shell. As these three families have gills of a peculiar and simple structure, each one consisting of two rows of flat lamella.'., attached to a single stem, they have recently been regarded as forming a special order (Protobrauchiata). This group is of special interest because of its great antiquity. Large numbers of fossil forms very closely allied to existing genera and species occur even in Silurian and Devonian formations. Thus the common living genera Nucula and Leda are represented by numerous Devonian species, many of which can not be separated from the recent forms, even as subgenera, by any tangible characters. Other species of the same age, referred to Palwoneilo, agree in nearly all essen- tial characters with the living genus Tindaria. These fossil shells are generally larger and stronger than the corresponding living species. Many Paheozoic genera which are now extinct were as highly organized and as much specialized as their living allies. The thin-shelled, strongly siphonate genera, such as Yoldia, Yoldi- ella, etc., do not appear so early in geological time and may be regarded as more modern specializations of the Leda-like forms. They are also the forms that swim and jump with the greatest activity. Therefore the thin and light character of their shells may be regarded as having been secondarily acquired, partly in consequence of their active move- ments, in which a heavy shell would be disadvantageous, and partly because the development of long siphons enables them to live concealed much of the time beneath the surface of the soft mud in which they generally live. In Solemya the shell is still lighter and thinner, in accordance with more developed swimming habits, combined with bur- rowing when at rest. Such forms as Nucula and Tindaria, which have no siphon tubes, must live at or near the surface of the nmd, over which they creep with their large expanded pedal disk. These have, for their protection, comparatively solid shells similar to those of Pakeozoic spe- cies, in form, texture, and sculpture. The family Nuculidai differs fromLedida3 mainly in having no siphon tubes, the mantle edges being completely disunited. The Ledida^ are remarkable for the great variations in the structure of the hinge-teeth, ligament, cartilage, and mantle, as well as in the form of the shell. The pallial sinus may be wanting or well- developed. Some genera have long united siphons ( Yoldia) ; some have shorter ones, more or less separated (Leda); while in Tindaria there is no true siphon, but only au Proc. IS". M. vol.. xx 850 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. efferent orifice differentiated. The ligament may be wholly external, as in Mallet-ia, Tindaria, etc., or it may be rudimentary and replaced by an internal cartilage or "resilium," or both may coexist in varying degrees of development and degeneration. The hinge teeth may be very numerous and regularly V-shaped in each series, or they may be com- paratively few and irregular, sometimes becoming oblique and lamelli- form (Silicula). The beaks generally turn backward (Yoldia, Leda, Nucula], but in Malletia, Tindaria. and some other genera they turn forward. On this account, when there is neither pallial sinus nor external ligament, it is often difficult, if not impossible, to tell which is the anterior end of the shell without the soft parts. Hence many fos- sil and some recent species have probably been reversed in the descrip- tions. Thus many of the Palaeozoic species referred to Nucida are described as having the beaks turned forward, the longer end of the shell being considered posterior, but in modern Rucuhc the beaks turn backward and the shorter end is posterior. Many of the deep-sea species with small, thin shells show no distinct muscular nor pallial scars, which increases this difficulty. When a differentiated external ligament is present, we have assumed that it is posterior to the beaks (opisthodetic), though a narrow extension usually runs under and for- ward of the beaks in a groove. When the shell of a dimyarian bivalve gapes posteriorly, the existence of a siphon may generally be assumed; for otherwise the internal soft parts would be exposed to enemies. The existence of a posterior rostrum or a protrusion of the posterior margin defined by an inferior emarginatiou indicates the existence of a siphon, or at least an anal tube, but these organs may exist without such mod- ifications of the shell. If these rules be applied to Palaeozoic forms we must conclude that the rostrate and subrostrate forms of Palcconeilo, etc., had some sort of a siphon, and therefore were not true Nuculidie. Numerous Palaeozoic species referred to the genus Paheoneilo proba- bly belong to or near the Tindarinae. Some of the species ] from the American Devonian rocks can hardly be distinguished from Tindaria by any important structural characters, unless it be the form of the teeth. It is probable that Nuculites and several related genera belong near this division, for they have an external ligament and no resiliuni. In these genera the plain, transverse teeth are very numerous and more simple than in the modern genera, seldom showing any trace of the acute, V-shaped form characteristic of most modern genera, though in some species the teeth are slightly angulated in the middle. Mr. Dall has proposed the family Ctenodontid;e 2 to include numerous Palaeozoic species belonging to Ctenodonla, and allied genera, some of which Zittel and others refer to Arcidie on account of their thickened pectuuculoid shells. They seem to be allied rather to Tindariuoe. 1 For example see P. constricta Hall, P. plana Hall in Paleontology of New York, V, Pt. i, pp. 333, 334, pi. XLVIII, figs. 1-28, 1885. - Trans. Wagner Free Inst., Ill, p. 515, 1895 No.1139. DEEP-WATER MOLLUSCA—VKIiBILL AND BUSJJ. 851 TheLedida',as here understood, were divided into five subfamilies by Fischer, namely: (1) Cucullellina- = Ctenodontidse Ball -f I'liltt'onrilo and ('iirdiolaria; ("2) Sareptina?. (for Sarepla only); (3) Ledina*; (4) Malletina- (including Tlii(l(trt7. We have included yuculhta in the ^uculida- with some doubt, because authors differ as to its structure. Some state that its liga- ment is wholly external and others to the contrary. Fischer places it in the Arcidre, near Limopsis, but it has no ligauiental area. Mr.Dall kindly forwarded to us excellent unpublished figures of two American species of this genus. In these the thickened ligament is external to the hinge-plate, on the end of the shell which is destitute of a lateral tooth, and is the shorter (posterior?). The beaks turn toward this end. Mr. Ball states that the shells are not distinctly nacreous within. The following are some of the known species: N. miliaris Ueshayes; N. ovalis S. Wood; N. calabra Seguenza, fossil; N. munita Carpenter, from the Catalin Islands; T. xntcntn A. Adams, from Korean Straits; N. add nisi Ball, from Florida and the West Indies. NUCULA Lamarck, 1799. Niicula LAMARCK, Prodrome d'uue Xouv. <•!. des ( 'oipiillrs, p. S7, \<>. lot, ITllM. Nttuiilaita LINK, Jiesdir. Ifost. Saminl., p. 155, 1807 (not of Adams, 1858, nor of Harris, 1897). Nucitla BALL, Bull. Mus. C'omp. Zool., XII, p. 245, 1886. Type. — Nucula nucleus Lamarck. Nuculana (Link) was an exact synonym or variant of \ucula, of earlier date, as the description plainly shows. There was, therefore, 852 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. no valid excuse for applying it to a different group (Leda), that had already received a valid name, as was done by H. and A. Adams. That a species belonging to Leda was mentioned by Link does not alter the case, for all the species of Leda, and Toldia then known were referred to Nucula by Lamarck and all other conchologists. NUCULA PROXIMA Say, variety OVATA, new. (Plates LXXXI, fig. 6; LXXXVIII, fig. 5.) We designate by this name a single specimen which differs so widely in form from the ordinary type of Nucula proximo, that it could well be taken for a distinct species if it had occurred in large numbers or in a remote locality. It is broad-ovate or elliptical in form and much less angular and oblique than the typical proxima. It is decidedly compressed with the umbos much less prominent than usual. The surface is glossy, grayish white, marked with distinct lines of growth aud microscopic radiating strine. The anterior end is evenly rounded and more produced than in proxima; the ventral margin is broadly and evenly rounded; the posterior end is obtuse, slightly produced and scarcely augulated; the postero dorsal margin is convex and slopes much less rapidly than in proxima, so that the posterior end is more evenly rounded aud broader. Internally the margin is plain. The hinge-teeth are much as inproxlma, but the two series are less curved and meet in a broad angle. Length, 3.5 mm.; height, 3 mm. One live specimen (No. 73407), station 863, in Vineyard Sound, off Cuttyhunk, in 18 fathoms, 1880. NUCULA SUBOVATA, new species. (Plates LXXXI, fig. 8; LXXXIII, fig. 5.) Shell small, broad-ovate, with somewhat prominent umbos, and rather acute, somewhat prominent beaks behind the middle. Surface smooth and lustrous, covered with rather regular, concentric lines of growth, which are scarcely visible to the naked eye. Epidermis thin, pale yellowish green. The autero-dorsal margin is nearly straight at first; then, forming a convex curve, slopes gradually to the bluntly rounded anterior end which is somewhat produced but not angulated; the postero-dorsal margin is convex, sloping rapidly, and forms a slight rounded angulation iu the middle of the posterior end, where it joins the broadly rounded, ventral margin. Hinge-margin rather broad and strong in proportion to the size of the shell, with a moderately large rounded, slightly oblique chondrophore projecting considerably within the margin. The portion of the hinge-plate behind the beaks is con- siderably shorter than that in front and bears about six, strong, V-shaped teeth of which the two distal ones and the two proximal ones are much smaller than the others; in front of the beaks it is broad and NO. 1139. DEEP-WATER MOLLUSC A— YERRILL AND BUSH. 853 strongly curved, and bears about nine broad, elevated, strong, trans- verse teeth of which five or six in the middle are much larger than the others; above these the outer hinge margin is somewhat expanded and everted. There is a thin, continuous ligament both before and behind the beaks. Epidermis thin, pale greenish yellow. The inner ventral margin is thin and plain. Length, 4.9 mm. ; height, 3.9 mm. Some of the smaller specimens have a narrower and less thickened hinge-plate with the teeth more delicate than in the type. Four specimens, at four stations, between N. lat. 40°, W. long. 71° 14' 30", and K lat. 37° 8', \V. long. 74° 33', in 157 to 444 fathoms, 1881-1885. This species has some resemblance to S. tennis, but it is much less oblique and more elongated in form, and is less inequilateral, the pos- terior end not being subtruucated, while the anterior end is narrower, relatively shorter, and much less oblique. The hinge-margin is also different; the teeth are fewer and much stronger, and the hinge-margin much broader, while the chondrophore is smaller, more rounded, much less oblique, and projects freely from the inner hinge-margin instead of being united closely to it. It also bears some resemblance in form to Nuctda pernambuccnsis Smith,1 but there are marked differences in the hinge and number of teeth. NUCULA GRANULOSA Verrill. (Plates LXXXI, fig. 2; LXXXVIII, fig. 8.) Nucula granulosa VEKHILL, Trans. Conn. Acad., VI, p. 280, 1884; Expl. Albatross, Report U. S. Com. Fish and Fisheries for 1883, p. 576, 1885.— DALL, Bull. U. S. Nat. Mus., No. 37, p. 42, 1889. Taken at about sixteen stations, between X. lat. 41° 53', W. long. 65° 35', and N. lat. 38° 30' 3", W. long. 73° 6', in 384 to 1,061 fathoms, 1880-1886. NUCULA VERRILLII Dall. (Plate XCV, fig. 10.) NuctiJa irigona VERRILL, Trans. Conn. Acad., VI, p. 438, 1885 (not Bronn, 1849. not Seguon/a, 1877). Nncnln rerriUH DALL, Bull. Mus. Coinp. Zool., XII, p. 248,1886; Bull. U. S. Nat. Mus., No. 37, p. 42, 1889 ; Pror. U. S. Nat. Mus., XII, p. 257, pi. xiv, fig. 4, 1889.- BUSH, Bull. Mus. Conip. Zool., XXIII, pp. 240, 243, pi. i, fig. 6, 1893. Comparatively few specimens, at six stations, between 1ST. lat. 39° 43' 45", W. long. 70° 7', and N. lat. 3(5° 47', W. long. 73° 9' 30", in 1,140 to 1,825 fathoms, 1884-1886. South to Yucatan, in 430 to 1,685 fathoms.— Dall. 1 Report Voy. Challenger, Zool. Lamellibrauchiata, XIII, p. 227, pi. xvm, figs. 10-10a, 1885. 854 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. NUCULA CANCELLATA Jeffreys. (Plates LXXXI, fig. 3; LXXXVI, fig. 5.) Xiicula CHHcellala VERIULL, Trans. Conn. Ac-ad., VI, pp. 231, 280, 1884; Expl. Alba- tross, Report V. S. Com. Fish and Fisheries for 1883, p. 576, 1885.— DALL, Bull. U. S. Nat. Mus., No. 37, p. 42, 1889 ; Proc. U. S. Nat. Mus., XII, p. 258, 1889. A very abundant species, at forty-four stations, between N. lat. 42° 47', W. long. 61° 4', and K lat, 37° 27', W. long. 73° 33', in 384 to 2,033 fathoms, 1883-1887. South to off Tobago, West Indies, in 880 fathoms.— Ball. Family Subfamily LETDUSTJE. LED A Schumacher, 1817. Leda VKRRILL and BUSH, Ainer. .Tonrn. Sci., Ill, pp. 54, (12, . January, 1897. Nitciilana HARRIS, Cat. British Museum, p. 348, 1897 (not Link, 1807). Type. — Leda rostrata (Montagu, 1808). This genus has been variously extended and restricted by authors, and several subgeueric and sectional groups have been proposed. In the more extended sense it is scarcely capable of a definition that will distinguish it from Yoldia, etc. We proposed, therefore, to restrict it to the typical species, such as L. cuspidal a Gould, L. caudata (Donovan), L. pernnla (Miiller), L. tenu- isulcata (Couthouy), and many others closely related. These have a long, tapered, bicarinate rostrum, and well-developed siphon tubes, partially united. The palpal tentacles are long, flat, tapered, and arise external to the bases of the outer palpi, which are broad with slender, acute, posterior tips. Mr. Harris quotes rostrata Liima?us as the type of his Nuculana, but no such species occurs until Gmelin's edition, 1790; rostrata Chem- nitz, 1784, used by Schumacher as the type of Leda, is now considered the same as flumatilis Sowerby and also Schrcet-er, 1779; rostrata Lamarck, 1819, is the same as pernula Miiller, 1774 or 6?, so that in using rostrata Montagu, 1808, we avoid confusion of names without leading to any misunderstanding of the form of the shell, for all of the above species have the same rostrated form. LEDA BUSHIANA Verrill. (Plates LXXIX, tig. 8; LXXXII, fig. 9.) Leda busMana YEKRILL, Trans. Conn. Acad., VI, pp. 229,280, 1884; Expl. Alba tross, Report U. S. Com. Fish and Fisheries for 1883, p. 576, 1885.— DALL, Bull. U. S. Nat. Mus., No. 37, p. 44, 1889. A few specimens, off Cape Hatteras, North Carolina, in 516 fathoms, 1883. South to Florida Straits, in 120 to 516 fathoms.— Dall. 1 Nuculanidw Harris, Australian Ter. Moll., Cat. British Museum, p. 348, 1897. NO. 1139. DEEP-WATER MOLLrSCA—VERRILL AXD BUSH. 855 LEDA PERNULA (Miiller). (Plate LXXXII. tig. 2.) Leda pernula G. O. SARS, Mollusra Ueg. Arctic.-!- Norvi-gin-. p. 35, pi. .">, ligs. 1 ti-l 7.T.SJJ. 863 W. long. 69° 1'2'. and K lat. 35° 12' 10", W. long. 74° 57' 15", in 22 to 516 fathoms, 1872-1885. The most prominent character of this species is the relatively lar^e si/e of the cartilage-pit which intersects both the hinge- margins and the beaks and is therefore plainly visible from the exterior. In outline it is similar to 1". iris and Y. in flat a but is more pointed and narrower posteriorly than either of them. They differ also in having much smaller cartilage-pits and in the number of the teeth. Specimens formerly identified as Yoldia obem Stimpson, agree per- fectly with authentic specimens of lucifla sent by Doctor Friele from Spitzbergeu. As none of the species known to us agree sufficiently well with the description and figure of Lerta obem Stimpson, for us to decide definitely as to its correct position, unless we are to consider the figure a very incorrect representation, we prefer to let it remain doubtfully, as a synonym of Y. lucid tt, where Jeffreys and others have placed it. YOLDIELLA IRIS, new species. (Plates LXXX, figs. 1, 2; LXXXII, fig. 11.) Shell small, thin, rather delicate, long-ovate or ovate-elliptical, with the beaks in front of the middle, not much swollen; surface smooth, or nearly so, with brilliant iridescence. The autero-dorsal margin is con- vex and slightly arched, sloping gradually to the obtusely rounded and slightly produced anterior end; ventral margin very broadly and evenly curved; posterior end obliquely ascending, obtusely pointed or rounded at the tip with a slight dorsal angulation; postero-dorsal mar- gin slightly convex, sloping but little, pinched up into a thin, rather prominent keel. The urnbos are small and prominent with the beaks small, curved inward and backward, closely appressed to the margin. The epidermis is grayish or greenish yellow, smooth and shining; the surface is brilliantly iridescent, covered with faintly marked, fine, con- centric lines, most distinct near the ventral margin and anteriorly; under the lens these appear like faint, close undulations over most of the surface. Escutcheon defined by a well-marked depression. The hinge-margin is thickened and forms a very obtuse angle at the beaks; the posterior portion which is only slightly curved distally is longer than the anterior which is nearly straight. In the largest speci- mens there are twelve or thirteen acute erect V-shaped teeth in each series, including one or two minute, proximal ones. The resilial pit is minute, situated on the inner face of the thin edentulous hinge-plate, beneath the beaks, and faces ventrally so that it is scarcely visible in a front view and but partially interrupts the hinge-plate. Outside the series of teeth, on both sides of the beak there is a smooth, raised margin. Length of one of the larger specimens, 7,~> nun.; height, 5 mm.; from beak to posterior end, 4.5 mm. 864 PROCEEDINGS OF THE NATIONAL MUSEUM. VOT..XX. Found in considerable numbers, at about forty-five stations, between N". lat. 47° 40', W. long. 47° 35' 30", and N. lat. 35° 12' 10", W. long. 74° 57' !">", in 20i to 781 fathoms, 1872-1880. This species is more elongated and more regularly elliptical than any of the allied species; the hinge-margin is also less angulated. A single specimen (No. 7 4325), station 43, off Cape Sable, in 90 fathoms, 1877, at first thought to be a distinct species, differs from the typical form in being more oblong with the ventral margin less curved, the posterior end more evenly rounded with only a slight indication of a superior angulation, so that the shell has a pretty regular, narrow ellip- tical form. In all other respects, however, it agrees well with the ordi- nary form. This specimen, which receives the varietal name stricta, is figured on Plate LXXX, fig. 1. Length, 5 mm.; height, 3 mm.; breadth, 1.3 mm.; length from beak to posterior end, 3 mm. YOLDIELLA INFLATA Verrill and Bush. (Plates LXXX. fig. 8; LXXXII, figs. 5, 6.) Yoldia liii'ida VERRILL, Trans. Conn. Acad., VI, p. 279, 1884 (in part). Yoldiella inflata VERUILL and BUSH, Amer. Journ. Sci., Ill, p. 56, figs. 3, 4, 11, January, 1897. Shell small, swollen, rather short, subovate, with the posterior end broad, angulated postero-dorsally ; beaks at about the anterior third; surface smooth. An tero- dorsal margin regularly convex and sloping rapidly to the anterior end which is evenly rounded, very obtuse, and passes insensibly into the evenly curved ventral margin which is decidedly convex, although the degree of convexity varies considerably in different specimens; the posterior end is obliquely subtruncated, with an obtuse curve below and an obtusely rounded angle at its upper extremity where it joins the nearly straight postero-dorsal margin. The umbos are full and well-rounded but not very prominent; the beaks are small, directly incurved, appressed to the margin. There is no distinct lunule but the margin is slightly pinched up in a small crest both before and behind the beaks. The ligament is delicate and shows slightly on both sides of the beak. Epidermis pale olive yellow or straw color; surface smooth, shining, reflecting prismatic colors, showing more or less distinct lines of growth which sometimes become regular, concentric, very fine striations, especially anteriorly. Hinge-margin well developed, moderately broad and considerably thickened, forming an obtuse angle at the beak where it is thin, encroached upon by the beak and interrupted by the cartilage-pit; the two portions are nearly equal in length, the anterior somewhat arched, the posterior nearly straight, each having a thin, smooth border above the teeth, about equal in breadth to the hinge-plate. In the largest specimens there are nine to eleven (most frequently ten) rather stout, angular teeth and about ten very similar posterior ones; the cartilage-pit is small and NO. 1139. DEEP-WATER MOLLUSCA—VERRILL AND BUSH. 865 just beneath the beak, forms a notch which completely interrupts the hinge-margin. Length of one of the largest specimens, 6 mm.; height, 4.5 mm., thickness, 3 mm.; from beak to posterior angle, 4 mm. Found in considerable numbers, at about twenty stations, between IT. lat. 41° 53', W. long. 65° 35', and K lat. 35° <)' 50", W. long. 74° 57' 40", in 516 to 1,608 fathoms, 1883-1886. Several live specimens, at station 2079, in 75 fathoms. This species is closely related to 1". htcida, (Loven), from whicli it is easily separated by its shorter, broader, more swollen form, its strongly curved ventral margin, and very distinct postero-dorsal angle. It is shorter and bas a broader posterior end than most of the related species. The resilium is not visible externally. YOLDIELLA SUBANGULATA, new species. (Plates LXXVII, fig. 3; LXXIX, fig. 6.) Very similar to the preceding species in form but less pointed pos- teriorly and larger. The umbos are small, not prominent; beaks are small, directly incurved, appressed to the hinge-margin but not dis- tinctly notched by the resilial pit. The antero-dorsal margin is convex, arched; the anterior end is a little produced, obtusely rounded; ven- tral margin evenly and broadly rounded, slightly produced posteriorly, forming an obscure obtuse angle as it merges into the posterior end which is obliquely subtruncated or a little iuflexed in the middle, with a prominent dorsal angle; the postero-dorsal margin slopes but little, and is nearly straight, with the compressed edges forming a slight keel, which is a little convex in the middle. A well-marked ridge runs to the postero-dorsal angle, and a less distinct one to the postero-ventral angle; between these there is a slight depression of the surface. Sur- face nearly smooth, lustrous, reflecting prismatic colors, and covered with faint lines of growth and a few inconspicuous irregular stilci; epidermis pale olive yellow. The hinge-margin is narrow, very obtusely angled, and is interrupted under the beaks by the small notch-like resilial pit. The anterior series of teeth is slightly arched and con- tains about seventeen teeth, including three or four minute proximal ones; the larger ones are high and sharp. The posterior series is a little longer and contains about eighteen, similar, but somewhat more slender teeth. A thin, smooth margin extends along outside both series. There is a small internal denticle at the front edge of the resilial pit. Pallial sinus narrow, considerably inflexed. Length, 8 mm. ; height, 5 mm. ; thickness, about 4 mm. ; from beak to anterior end, 3 mm.; posterior end, 5 mm. One live specimen was dredged by the Baclie at station 46, 1ST. lat. 43° 3' ; W. long. 70° 4', in 51 fathoms, 1874. Proc. N. M. vol. xx 55 866 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. YOLDIELLA JEFFREYSI (Hidalgo). (Plates LXXXI, tig. 5; LXXXIII, fig. 3.) Lcda lata JEFFREYS, Aim. Mag. Nat. Hist., p. 431, November, 1876. Leda Jeffrey si JEFFREYS, Proc. Zool. Soc. London, p. 579, pi. XLVI, fig. 2, Jnne, 1879. — SMITH, E. A., Report Voy. Challenger, Zool. Lamellibranchiata, XIII, p. 234, 1885. Not Yoldiajeffreysi VERRILL, Trans. Conn. Acad., VI, p. 229, 1884. Shell small, ovate- elliptical, somewhat thick for its size, rather swol- len, covered with a glossy, iridescent, brownish yellow epidermis. The posterior end is considerably the longer, somewhat narrowed, bluntly rounded without any distinct rostrum, limbos rather prominent, some- what swollen; beaks prominent, curved inward and backward. The autero-dorsal margin is broadly convex, slopes a little and becomes continuous with the rather regularly curved outline of the rounded anterior end ; ventral margin is broadly and regularly curved without any distinct flexure; the posterior end is obtusely rounded and not defined by any radial lines or ridges, with the dorsal margin nearly straight at first, usually slightly convex in the middle, and sloping gradually. The surface beneath the epidermis is nearly smooth but shows more or less distinct lines of growth, which sometimes have the form of fine parallel striations. The hinge-plate is thickened and rather strong; the two series of teeth are long and form a very obtuse angle at the beak; the anterior is somewhat the shorter and more oblique and a little curved. In our type specimen there are thirteen anterior teeth of which three or four proximal ones are very small; and fifteen posterior ones, including four or five small proximal ones; a somewhat larger specimen has fifteen in the anterior series and eight- een in the posterior. The two series are interrupted beneath the beak by a small, well-defined, concave, triangular resilial pit supported on the inner side by a distinct shelf-like projection. Length of the type- specimen, 5 mm.; height, 3.1 mm. Length of the largest specimen, 5.6 mm.; height, 4.2 mm. Six separate valves, at three stations, between K. lat. 37° 38' 40", W. long. 73o 16' 30", and K. lat. 36° 42', W. long. 74° 30', in 727 to 1,423 fathoms, 1884-1886. As all of our specimens are much larger than the measurements given by Jeffreys, they are referred to ~Y. Jeffrey si (Hidalgo) with some doubt, although they appear to agree well with Jeffreys's figure of that species in form and in the character of the hinge. YOLDIELLA LENTICULA (Mbller) variety AMELIA, new.- (Plates LXXX, fig. 9; LXXXI, fig. 4.) Nucula lenticula MOLLEK, Iml. Moll. Groenl., p. 17, 1842. Yoldia abyssicola TORELL, Spitzbergens Molluskfauna, p. 149, pi. i, ngs. 4, a-b, 1859. Portlandia lenticula G. O. SARS, Mollusca Reg. Arcticte Norvegise, p. 39, pi. 4, figs. 10, a-b, 1878. Lena lenticula JEFFREYS, Proc. Zool. Soc., London, p. 577, June, 1879. NO. 1139. DEEP-WATER MOLLUSCA—VEEEILL AND BUSH. 867 Our specimens, which are worn and imperfect, referred to this north- ern species, differ somewhat from the typical specimens from Spitz- bergeu, received from Doctor Friele. They are relatively shorter, higher, and somewhat less swollen, with a thicker and heavier shell. The posterior end is less produced and less tapered, so that it has a more ovate form. The hinge-teeth are stouter; the posterior series is shorter but contains the same number of teeth in specimens of similar size. With the amount of material that we have for examination, the differences, however, seem hardly sufficient to warrant the separation of our shells as a distinct species. We therefore propose the varietal name unthlia for our specimens. A few separate valves, at two stations, north of Cape Cod, in 110 to 1131* fathoms, 1878-79. YOLDIELLA FRATERNA, new species. (Plates LXXX, fig. 5; LXXXII, fig. 8.) Toldia friyida VEKRILL, Trans. Conn. Acad., VI, p. 279, 1884; Expl. Albatross, Eeport U. S. Com. Fish and Fisheries for 1883, p. 576, 1885 (in part). Shell small, thin, delicate, irregularly elliptical in form, the posterior end being a little the longer, unusually broad, and slightly produced above, but not distinctly augulated. with a glossy, iridescent, yellow- ish green epidermis. Umbos a little swollen ; the beaks small, scarcely prominent, and subcentral. The anterior end is broad, a little produced in the middle, and obtusely rounded; the dorsal margin is nearly horizontal in the region of the teeth; distally, sharp, and convex, then sloping rapidly to the middle of the anterior end. The ventral margin is broadly rounded, expanding a little posteriorly and then ascending pretty rapidly to the posterior tip which is obtusely rounded superi- orly; postero-dorsal margin slightly convex and nearly horizontal for the greater part of its length. The surface beneath the epidermis is marked only by faint lines of growth. The hinge-margin is thin, rather delicate, with the two series of teeth of nearly equal length and diverging from the beaks at a broad angle; each series contains about ten rather thin and delicate teeth, of which the one or two proximal ones are very small and rather indistinct. Beneath the beak the margin is attenuated and interrupted by a small, oblong resilium which occupies the entire thickness of the margin and a slight notch in the beak. The pallial sinus is relatively rather large and deep, but in most specimens is invisible. Length of the figured .specimen, 4 mm.; height, about 2£ mm. A comparatively small number of specimens, at about twenty sta- tions, between N. lat, 47° 40', W. long. 47° 35' 30", and N. lat. 37° 8', W. long. 74° 33', in 90 to 1,608 fathoms, 1873-1886. This is a deep-water form formerly identified by us as Yoltlia friyida Torell. 868 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. YOLDIELLA CURTA, new species. (Plate XCVII, fig. 8.) Fhascolus ovatus (?) VERRILL, Trans. Conn. Acad., VI, p. 230, 1884 ; Expl. Albatross. Eeport U. S. Com. Fish and Fisheries for 1883, p. 576, 1885 (not Seguenza). Shell small, short-ovate, rather swollen iii the middle, with rather prominent umbos, somewhat inequilateral, the posterior end the longer and slightly produced. Beaks small, incurved, with a slight posterior twist and a little separated from the margin. The dorsal margin is nearly straight medially, both before and behind the beaks, anteriorly it merges gradually into the broadly rounded anterior end, which usually has an obscure, blunt angulation in the middle; ventral mar- gin broadly and evenly rounded, merging gradually into the more abrupt curve of the posterior end which is a little tapered, but obtusely rounded without any distinct rostrum or angulatiou ; the postero-dorsal margin is a little prominent, pinched up and convex, with a considera- ble slope, so that the tip of the shell is but little above the middle. The surface is polished and somewhat iridescent, marked only by fine, irregular lines of growth. Epidermis pale greenish or brownish yellow. There is a relatively very large resilium, appearing yoke-shaped or wide W-shaped in the separated valves, and covering a relatively long, edentulous space beneath the beaks. The teeth are compressed, oblique, imperfectly V-shaped, especially posteriorly, and but slightly elevated. There are six or seven in the posterior series, of which the proximal ones are rather indistinct; and four distinct and two or three indistinct ones in the anterior series. In a dorsal view five are visible above the margin behind the beak and four before. They are not very long and rather blunt, with the distal side sloping and the side next the beak a little incurved and concave. Length, 2.6 mm.; height, 1.8 mm.; thickness, about 1 mm. A few live specimens, at three stations, between N. lat. 41° 11' 30", W. long. 66° 12' 20", and K lat. 39° 38', W. long. 70° 22', in 499 to 1,290 fathoms, 1883-1886. This species somewhat resembles Y. frigida in form, but it is rela- tively shorter, higher and less distinctly rostrated. Its hinge is also quite different. The present species is peculiar in having fewer and blunter teeth and a much larger resilium than most of the related species. YOLDIELLA PACHIA, new species. Shell very broad, oval, considerably swollen in the middle, with the length and height nearly equal; umbos rather prominent. The poste- rior end is narrowed and slightly produced, but not denned by any groove or carination. The dorsal margin is very obtusely angulated, anteriorly it is convex and slopes pretty rapidly to the broadly and evenly rounded anterior end ; posteriorly it is nearly straight at first, then slopes gradually to the posterior end. The ventral margin is very No. 1139. DEEP-WATER MOLLUSC A— VERRILL AND BUSH. 869 broadly rounded ami slightly produced in the middle; it joins the curve of the posterior end with a scarcely perceptible incurvature in some specimens; the posterior end is obtusely rounded and situated about midheight of the shell. The dorsal edges of the valve are thin and a little pinched up, but there is no distinct lunule and only a very nar- row liguinental furrow. The epidermis is polished and somewhat iri- descent, and marked witli fine, somewhat irregular lines of growth, in some places showing faint, microscopic, radial striations. Color of the dead valves, brownish yellow. Hinge-plate strong, narrow near the beak, wide distally, strongly angled, with the outer edge naked and rather broad, especially anteriorly. Teeth large and prominent dis- tally, with about three small proximal ones; about eight in the ante- rior and ten in the posterior series. The resilial pit is a distinct, triangular fossette, or chondrophore, on the face of the margin, cover- ing its whole breadth, and bordered internally by a thickened edge which causes an excurvature of the margin. There is a distinct mar- ginal external ligament and furrow, or escutcheon. Length, 4.0 mm.; height, 4.8 mm. Three separate valves, among Foraminifera, at station 2385, N. lat. 28° 51', W. long. 88° 18', in 730 fathoms, 1885. In outline this species resembles Y. curta, but differs in its wider and stouter hinge-plate, more numerous and more highly developed teeth, and especially in the form and structure of the resilial pit. YOLDIELLA INCONSPICUA, new species. (Plate LXXIX, figs. 3, r>.) Shell small, thin, delicate, compressed, subovate; posterior end a lit- tle produced and narrowed medially. Surface lustrous and iridescent. Uinbos scarcely prominent; beaks small, projecting but little above the dorsal margin. The antero-dorsal margin is slightly convex and nearly horizontal at first, then slopes gradually to the evenly rounded anterior end; ventral margin broadly rounded, slightly swollen posteriorly, ascending more rapidly to the narrow and bluntly rounded posterior end; postero-dorsal margin nearly straight toward the beak, then slightly convex and sloping very gradually. The surface is covered with fine, pretty regular, concentric grooves and raised lines, visible only under the microscope. Epidermis thin, shining, iridescent, green- ish yellow. The hinge-margin is thin and delicate, nearly straight; the two series of teeth form a very obtuse angle at the beaks and are interrupted, for a considerable space, by the resiliuin which does not lie in a distinct pit. The ligament shows as a delicate, continuous mar- ginal line, both in front of and behind the beaks. The teeth are small, oblique, V-shaped. In the anterior series there are about six distinct ones with one or two minute proximal ones; in the posterior, about seven distinct ones with one or two rudimentary ones near the beak. 870 PROCEEDINGS OF TSE NATIONAL MUSEUM. VOL.XX. The pallial sinus is rather wide and moderately deep, but is invisible in most specimens. Length of the largest specimen. 3.G mm.; height, 2.3 mm. A number of specimens, at about fifteen stations, between !N". lat. 42° 33', W. long. 09° 58.5', and K lat. 35° 12' 10", W. long. 74° 57' 15", in 100 to 705 fathoms, 1878-18SG. This species is distinguished from Yoldiella frigida, and most of the other small species which it resembles, by its narrower, or lower, and more compressed form, more delicate shell, straighter dorsal margin, and the more central prolongation of the posterior end. It is appar- ently more nearly related to the smaller species, I", minuscula, than to any other. The latter has a smaller, shorter, and more swollen shell, more convex veutrally, with the hinge-margin somewhat more angulated. YOLDIELLA MINUSCULA, new species. (Plato LXXIX, figs. 2,7.) Toldia Jeffreys! VERRILL, Trans. Conn. Acad., VI, pp. 229, 279, 1884; Expl. Albatross, Report U. S. Corn. Fish and Fisheries for 1883, p. 576, 1885. Shell minute, broad-ovate, covered with microscopic, pretty regular concentric striations, with a very lustrous, somewhat iridescent, yel- lowish epidermis. The two ends are nearly equal in length; the posterior somewhat narrowed and obtuse at the end, the anterior well- rounded. The uinbos are not prominent and the beaks are very small and project but slightly above the margin. The antero-dorsal margin is slightly convex at first, and nearly horizontal, and passes gradually into the curve of the anterior end; ventral margin is broad and nearly uniformly convex ; the posterior end is a little produced in the middle and forms there a slight obtuse angle; the postero-dorsal margin is a little convex and nearly horizontal at first and then slopes rather rapidly to the tip. The hinge-margin is thin and delicate; the two series of teeth lie nearly in a straight line but the anterior one is a little oblique, so that they form a very wide angle at the beaks where the resilium entirely interrupts the hinge-margin forming a wide notch without any definite pit or shelf; the teeth are small, very oblique, and only slightly prominent; there are only about five in the anterior and six in the posterior series. Length, about 2.3 mm.; height, about 1.5 mm. Only a few specimens, at four stations, between N. lat 41° 53', W. long. 65° 35', and N. lat. 38° 27', W. long. 73° 2', in 705 to 1,200 fathoms, 1883-1885. This very minute species may, with a larger series, prove Jx) be the young of some of the preceding species. NO. 1139. DEEP-WATER MOLLUSCA—VEKEILL AND BUSH. 871 YOLDIELLA SUBEQUILATERA (Jeffreys). Leda subet/uilatera JEFFREYS, Proo. /oul. So<-.. London, p. 579, pi. XLVI, fig. 3, 187!». Toldia 8nbel,1i. 14, 1889. Several live specimens (No. 35204), from station 2037, N. lat. 38° 53', W. long. 69° 23' 30", in 1,731 fathoms, 1883, have been referred to this species. Although younger or smaller than Jeffreys's type, they agree very closely with his figures and description. The shell is very small, very thin and transparent, polished, lustrous, but scarcely iridescent and marked only by microscopic lines of growth. It is rather com- pressed, nearly elliptical in form, with the beaks prominent above the dorsal margin and turned almost directly hi ward. Both ends are obtusely rounded and nearly equal in length, so that it is impossible to determine which is anterior and which is posterior by the external characters; one end, supposed to be the anterior, is however slightly broader than the other. There is no distinct ligament visible externally. The hinge plate is nearly straight, the two series of teeth forming but a slight angle. Interior not seen. Our specimens measure from 1.5 to 2.5 mm. in length. South to Grenada, in , 1878. — JEFFREYS, Proc. Zool. Soc., London, p. 586, June, 1879. — VER- RILL, Trans. Conn. Acad., VI, pp. 226, 280, 1884; Expl. Albatross, Report U. S. Com. Fish and Fisheries for 1883, p. 576, 1885.— SMITH, E. A., Report Voy. Challenger, Zool. Lamellibrauchiata, XIII, p. 245, 1885.— BALL, Bull. U. S. Nat. Mus., No. 37, p. 46, 1889.— BUSH, Bui. Mas. Comp. Zool., XXIII, p. 234, 1893. — LOCARD, Campague du Caudan, Anuales de I'Universite" de Lyon, p. 202, 1896.— VERRILL and BUSH, Amer. Journ. Sci., Ill, p. 57, fig. 9, 1897. The soft parts of several specimens, rather poorly preserved in alco- hol, have been examined. They have a large foot with an ovate disk pointed in front and minutely crenulated. The siphon tube is rather long and slender, in some cases not entirely retracted within the shell; it appears to contain both the branchial and anal tubes which are closely united quite to the simple tips; at the inner base, there is a well-marked siphonal septum. The gills are small, elongated, pointed posteriorly, and have the structure usual in the family. The palpi are rather large, elongated, with re volute margins; the palpal tentacle is very long and slender, and in the contracted state variously bent with the edge much convoluted. No pallial tentacle was found at the base of the siphon. In our collection there is a large series of this species; the form is pretty constant and in nearly all cases is more oblong than the Euro- pean species, as figured by G-. O. Sars. The small specimens are com- pressed while the large ones are a little swollen. The umbos are small, but slightly elevated; the beaks are very small, turned directly inward, and are almost in contact with the margin, so that they are generally worn away in the larger specimens. Directly under, and partly in the beaks, and also cutting more or less into the thickness of the external side of the hinge-margin, there is a small notch, or shallow excavation, which is occupied by a special portion of the ligament that probably represents a remnant of a degenerated resilium. The true ligament is well developed and prominent for about one-half the length of the hinge-margin, then becomes abruptly thinner and nar- »o. 1139. DEEP-WATER MOLLUSCA—VERRILL AND BUSS. 875 rower; its groove is narrow and inconspicuous. The hinge-margin itself is rather thin and bears very numerous, erect, V-shaped, acute teeth which number, in the large specimens, about sixteen or seventeen in the anterior series and about thirty-two or thirty-three in the poste- rior, including a number of small proximal ones; beneath the beaks there is a smooth, edentulous space, often a little thickened at the inner margin and projecting a little inward in the middle, and continuing inside the series of small proximal teeth on each side. In some cases this thickened border seems to arise anteriorly and to pass under the posterior series, as a slight fold; in other cases it is continued directly from one series to the other. The posterior series is nearly straight and about twice as long as the anterior which is strongly curved and distally somewhat recedes from the thin dorsal margin. The anterior end of the shell is rather short and evenly rounded; the posterior is about twice as long, a little wider owing to a slight ventral expansion, compressed and obtusely rounded or subtruncated at the margin, but without any distinct carination or angulation. The pallia! sinus is very broad and deep, extending nearly to the middle of the shell. The inner surface is smooth, white or grayish white. The exterior is smooth, except for the delicate lines of growth, and covered with a thin, brilliantly iridescent epidermis which, in live specimens, is pale yellowish green, but in dead valves is pale straw color. Our larger specimens measure about 15 or 1C inm. in length and 9 or 9.5 mm. in height. Found at many stations between N. lat. 41° 28', W. long. 65° 35', and K lat. 35° 16', W. long. 75° 2' 30", in r>lG to 1,781 fathoms, 1883-1887. MALLETIA ABYSSORUM, new species. (Plate XC VII, tig. 7.) Shell small, not much compressed, lustrous, iridescent, subovate, not gaping, decidedly inequilateral, with the posterior end the longer, broader, obtusely rounded, without any distinct rostration. Ulnbos rather prominent, rising above the outline of the dorsal margin, with small beaks turned backward at the tip. Lunule and escutcheon abor- tive. The short antero-dorsal margin is slightly concave, and slopes rapidly to the slightly angulated anterior end; the ventral margin is very broadly and evenly convex, the curvature receding somewhat pos- teriorly, so that the greatest height of the shell is somewhat back of the middle, posteriorly there is a slight extension of the edge correspond- ing to an indistinct radial ridge; the posterior end is very broad, obtuse, not angulated, with the dorsal margin nearly horizontal, slightly convex, compressed and forming a slight angle where it joins the poste- rior curve. A very slight groove defines a very faint escutcheon, along the edge of which the teeth can be seen through the substance of the shell. The surface is polished, brilliantly iridescent, and is marked by faint, raised, concentric lines, or ridges parallel with the lines of growth 5 876 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. near the ventral margin these become more elevated, clearly defined, and are separated by wider, slightly concave grooves. The hinge-plate is rather thin and delicate, regularly curved, without any angle at the beaks, with the posterior portion considerably the longer. There is a small, median, specialized ligament which occupies a lunate, or nearly semicircular notch in the hinge-plate directly beneath the beak, which does not extend through its entire width although it is here quite nar- row. The posterior ligament is pretty well developed and extends from the beak, where it is closely connected with the median portion, nearly to the distal end of the series of teetb, and occupies a distinct marginal groove; the portion nearest the beaks, opposite the smaller teeth, is thicker and darker colored than the rest and projects slightly, in a dorsal view; a delicate, inconspicuous portion continues a little in front of the beak, in a thin groove. The median portion of the liga- ment is so closely connected with the posterior portion that it appears to be a specialized, thickened portion of it, but is evidently homologous with the resilium of other genera; it is situated, however, outside the series of teeth and must serve as a ligament. Tlie larger teeth are deli- cate, subacute, V shape, compressed in a direction parallel with the dorsal margin, with deep pits between them. There are about ten in the anterior series, including three or four, very small, scarcely raised ones next the beak; and fourteen in the posterior series, of which the seven distal ones are decidedly larger than the rest, the tenth to the thirteenth being the largest; about four, next the proximal end of the series, are like small, rounded tubercles or granules without a V-shape form; following these are three of intermediate form, increasing in size distally, the seventh being more or less V-shaped; these smaller teeth form a series along the inner edge of the hinge-plate. An edentulous ridge, about as long as the space occupied by the first three teetb, extends from the first tooth to the ligament-pit and is continuous with a similar, thinner ridge running below the ligament-pit to the anterior series of teeth. The pallial sinus is of moderate size and triangular iu form. Length, 5 mm.; height, 4 mm. One live specimen (No. 52159), station 2566, off Chesapeake Bay, in 2,620 fathoms, 1885. MALLETIA POLITA, new species. (Plate LXXXII, fig. 10.) Shell of moderate size, irregularly ovate, somewhat swollen, the ven- tral region convex and the posterior end somewhat produced with a short rostrum. Epidermis light yellow, lustrous and iridescent, limbos not prominent, beaks small, strongly incurved, only slightly elevated above the margin. The antero-dorsal margin is slightly convex and slopes gently to the short, obtusely rounded anterior end which is slightly augulated in the middle; the ventral margin is strongly con- NO. 1139. DEEP-WATER MOLLUSC A— VEREILL AND BUSH. 877 vex, a little produced in tlie middle, and with a slight incurvature toward the posterior end, below the rostrum ; the posterior end is nar- rowed and produced into a short obtuse rostrum with a nearly straight dorsal margin. The surface is covered with rather fine, somewhat uneven, concentric lines and undulations. The hinge-margin is but little thickened ; the anterior portion is the shorter and the more curved and forms a very obtuse angle with the posterior portion which is nearly straight. There are about twelve conspicuous, rather elevated, sharp teeth in the anterior series besides three or four minute, proxi- mal ones; and more than twenty in the posterior series, the number being indeterminable owing to an injury to the margin close to the beak. The external ligament is large and conspicuous and occupies a marginal groove extending the entire length of the posterior series of teeth. There appears to have been no chondrophore, but whether the line of teeth was continuous is uncertain. Length, 14.5 mm.; height, 9 mm. One valve (No. 78972), station 2718, N. lat. 38° 24', W. long. 71° 52', in 1,569 fathoms, 1886. NEILO Adams, 1858. Neilo H. and A. ADAMS, Genera of Recent Mollusca, II, p. f>l!l; III, pi. cxxvi, figs. 7, la, 76, 1858.— VERKILL and BUSH, Ainer. Journ. .Sri., Ill, pp. 57, 63, January, 1897. Type. — Neilo cumingii Adams. The type species of this genus has an oblong shell, with a straight postero-dorsal margin and a well-defined rostrum, bounded beneath by a pronounced furrow and a marginal indentation, while more veutrally, the margin protrudes somewhat, the pouting of the margin correspond- ing with special lobes of the margin of the mantle. N. cumingii from New Zealand is concentrically grooved, but N. goniura (Ball)1 from off the coast of Ecuador is smooth or nearly so. NEILONELLA Dall, 1881. Saturnia SKGUENZA, Nuculidi terziurie nierid. d' Ital., R. Accad. Lincei, I, p. 1178, 1877 (not Srhrank, 1801'). Leda (section Xeilonella) DALL, Bull. Mus. Comp. Zool., IX, p. 125, 1881; XII, p. 254, ISSG.+Salurnia Dall, p. 263. NeiloneUa VEKUILL, and BUSH, Amer. Journ. Sci., Ill, pp. 57, 63, January, 1897. Type. — NeiloneUa, corpulenta Dall. Shell small, swollen, short ovate, with both ends obtuse; the poste- rior somewhat the longer, blunt at tip, without any distinct rostrum or carina. Exterior usually concentrically grooved. Ligamental area not defined. Beaks usually prominent and turned inward and slightly backward. Ligament well developed, extending under and before the beaks in a distinct groove, more prominent behind. Eesilium very 1 Dall, Proc. U. S. Nat. Mus., XII, p. 251, pi. x, fig. 10, 1889. 878 PROCEEDINGS OF THE NATIONAL MUSEl'U. VOL. xx. minute or nearly abortive, occupying1 a slight notch in the dorsal margin under the beak, external to the series of teeth, which are inter- rupted only by a small, thin edentulous space. Pallial sinus small. Siphon tubes short. Labial palpi large, broad, crescent-shaped, with long tentacular appendages. Gills small, triquetral. We consider this group worthy of generic rank. It appears to be more nearly allied to Mnlletia than to Yoldiaur Leila. We can find no generic characters to distinguish Ball's typical species (N. corpulent a) from N.pusio, which was the type of the section, Saturnia, proposed by Seguenza. They agree closely in form, external sculpture, arrange- ment of the teeth, and structure of ligament and resilium. The name, Saturniaj being preoccupied by Schrank, 1802, we have adopted Ball's name for both of his sections. The following species appear to belong here: N~. corpulenta Ball (type), and N~. quadrangularis (Ball), West Indies; N.sericea (Jeffreys), Ireland and Portugal; N.pusio (Philippi), Medi- terranean and West Indies; N. subovata Verrill and Bush, from off Cape Hatteras, North Carolina, northward. NEILONELLA SUBOVATA Verrill and Bush. (Plates LXXX, fig. 10; LXXXII, figs. 3, 4.) Yoldia sericca JEFFREYS, var. strlolata VKRKILL, Trails. Conn. Acad., VI, p. '226, 1884.— VERRILL, Expl. Albatross, Report U. S. Com. Fish and Fisheries j'or 1883, p. 576, 1885. Neilonella- suboi-ala VEKRILL and BUSH, Anier. Jouru. Sci., Ill, p. 57, figs. 7, 8, 22, January, 1897. Shell somewhat swollen, subovate, with the dorsal margin angulated and the umbos somewhat prominent. The antero-dorsal margin is somewhat convex, pinched up at the edge, and sloped gradually to the evenly rounded anterior end; ventral margin is broadly and nearly evenly rounded throughout, without any sinuosity, and forms a blunt point at its junction with the postero-dorsal margin, which is nearly straight or slightly convex for the greater part of its length, with the edge thin and pinched up. The umbos are somewhat prominent and the beaks curve strongly inward and incline a little backward at the tip. The ligament is well developed, dark brown, and as seen in a dorsal view, fills a narrow, lanceolate excavation in the margin just behind the beaks. In an interior view it is conspicuous behind the beaks and occupies a curved notch immediately under them, and ex- tends forward for a short distance in a thin, marginal groove. The resilium is abortive or nearly so; in many cases it appears to be repre- sented by a minute black speck, adherent to the ligament, and occu- pying a minute indentation in the edge of the hinge-margin directly beneath the beak, external to the series of teeth. The hinge-margin is broad and rather strong, becoming very narrow below the beak but without a distinct notch or choudrophore; the posterior portion is NO. 1139. i>Ei-:r-\v. \rr.u MOLL i sc.t— rr-:i;i;iu. .txi> r.rsn. 879 • . nearly straight, the less oblique and considerably the longer, and forms a broad angle with the anterior. There are in the largest examples about eleven or twelve teeth in the anterior series, counting four or five very small proximal ones; and in the posterior series, fifteen or sixteen teeth of which the five or six proximal ones are minute. In ninny specimens the two series are not distinctly separated under the beak, in others there is a very minute, edentulous space in line with the minute ligamental notch. The largest teeth in the middle of each series are very elongated, erect, acute, with the tips turned upward toward the margin. The surface of the shell is covered with very regular, concentric sulcations separated by narrow, evenly rounded ridges of about the same width; in most cases this sculpture is faint or nearly obsolete toward the postero-dorsal margin and on the umbos. In many specimens, a number of faint radiating stria- run from the umbos to the antero-ventral margin, similar lines sometimes occur posteriorly. The epidermis is without much luster, of either greenish yellow, light yellow, or straw color, more or less iridescent, especially near the umbos. Along the dorsal margin the outline of the teeth can be imperfectly seen through the substance of the shell. The interior in fresh specimens is lustrous bluish white and in some cases is distinctly tinged with pale flesh-color. The muscular and pal- lial impressions are usually indistinct but some specimens show a small, but distinct, angular pallial sinus. The alcoholic specimens when dissected were found to have a short siphon and a large, stout foot with a broad disk having strongly creii- ulated edges. The labial palpi were long, crescent-shaped and the tentacle-like appendages arising from the outer bases of the external palpi were very long, slender, and coiled in a spiral. The gills were long, narrow, and prismatic, one on each side. Length of one of the largest specimens, (3.5 mm.; height, 4.6 mm.; thickness, about 3.5 mm. Young specimens about 2 mm. long are more equilateral than the adults and have the posterior end less produced and more evenly rounded, the umbos decidedly prominent, and the surface covered with fine, regular, concentric .grooves, the epidermis showing distinct iri- descence. Found in large numbers, at many stations, between X. lat. 42° 47'. W. long. 61° 4', and K. lat. 35° 9' 50", W. long. 74° 57' 40", in 125i to 1,731 fathoms, 1883-1887. This species shows considerable variation in form when a large series of specimens from the same locality are compared. Some are decidedly more elongated and tapered posteriorly than the typical form, others are somewhat shorter and more regularly ovate with the posterior end blunter or more rounded; all agree essentially in sculpture and in the peculiar structure of the hinge and ligament. This species has some resemblance to N. sericca Jeffreys, of which it 880 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. was formerly thought to be a variety. It differs, however, in its larger size, more ovate form, the posterior end being more produced and tapered, and in its stronger sculpture. N. corpulentaDallis narrower, more elongated, with more prominent beaks. N. quadrawgularis (D&I1) is shorter and more triangular in form, with the postero-dorsal margin more oblique. Subfamily TIND^ItlNJE A^errill and Bush. CuciiUeUhiusn, Amer. .Tourii. Sri., III. pp. 59, 63, .January, 1897. Type. — Thiilariopsis Ill'SH. 885 /(A. Shell lanceolate or long-ovate, posteriorly narrowed and somewhat elon- gated, more or less sinuous below ; rostrum slightly defined, smooth or slightly carin.ite; external ligament feebly developed Yoldia (sense restrirted). Jilih. Shell oblong, smooth, plain, blunt and rounded at both ends, without any distinct earina. sinuosity or rostrum Orthoyoldia Verrill and Hush. Ihhh. Shell thin, compressed, narrow-lanceolate or long-elliptical, nearly (Mini- lateral, and gaping at both ends; sculpture oblique. Adratta H. and A. Adams. hhhlili. Shell hyaline, oblong-ovate, broad posteriorly, concentrically sculp- tured, rostrum nearly obsolete AdraneUa Verrill and Hush. es long; pallial sinus large; shell elongated, gaping. p. Shell oblong or elliptical, blunt posteriorly, not distinctly rostrate; series of teeth unequal; those in the anterior series fewer Mullet la Desmoulius. pp. Shell long-ovate or oblong, broadly angulated and sinuous posteriorly; dis- tinctly rostrate and carinate; two series of teeth nearly equal. Neilo H. and A. Adams. oo. Siphon and pallial sinus small, shell ovate, not gaping; a rudimentary mar- ginal resilium NeiloiieUa Dall. DD. Shell short-ovate or subcordate, closed at Jjoth ends, umljos prominent; liga- ment entirely external; series of teeth generally continuous. Tiudariiur Verrill and Bush. ». Shell regularly ovate, grooved, without rostrum or earina; beaks turned forward ; no pallial sinus Tindaria Bellardi. ss. Shell ovate, with a distinct posterior sinuosity and a short rostrum. Tindariopsis Verrill and Hush. Family SOLEXOMY1DJE. SOLEMYA GRANDIS, new species. (Plate LXXXV1. ligs. 1, 2.) Sliell large, considerably broader anteriorly than posteriorly, dorsal margin in front of the beaks straight and thickened by an internal ridge and a strong epidermal fold. At the anterior end the valves gape- widely, and the edge of each is divided into six or seven long, nearly regular, digitate processes of nearly uniform width, and obtusely rounded at the ends, separated by notches, rounded proximally. The {-'gfi PROCEEDINGS OF TEE XATIO3AL MUSEUM. VOL.XX. general outline of this end is broadly truncate; the ventral margin is somewhat convex but slopes upward toward the posterior end and is nearly straight along the middle; the posterior end is short, evenly rounded, with the dorsal margin, behind the beaks, strongly incurved; the large black ligament which occupies this area is continuous with the epidermis, so that its outline forms a curve nearly in line with that of the anterior end, and shows but a slight angle, or lobe, at the outer end of the dorsal line. The uinbos are flattened, and scarcely prominent. The whole surface is covered with a thick, smooth, glossy epidermis, chestnut-brown in the young and brownish black in adult, which ante- riorly is divided into several rather broad digitations that are shorter and somewhat wider veutrally, their length diminishing from the mid- dle of the anterior end to the ventral margin, along the middle of which there are no digitations, but short and broad ones again appear pos- teriorly. The shell is sculptured by radiating ribs and furrows which are but slightly developed on the middle region but become large and strong anteriorly and smaller and closer posteriorly. On the anterior part these ribs are broad and flat, separated by wide, flat-bottomed, furrows often nearly as wide as the ribs; on the middle area, the fur- rows are shallow and rounded while the intervening spaces are flat, sometimes broad, at others narrow, this region appearing comparatively smooth, some specimens showing but slight indications of grooves and ribs; posteriorly these are somewhat more numerous, narrower, often about equal iu width. In specimens of medium size, there are from six to eight of the large anterior furrows and as many ribs; the edges of the latter are somewhat elevated above the middle portion and these thickened margins extend out along the edges of the digitations which otherwise conespond to the furrows. Internally the shell is white, moderately thick, the anterior portion oblong with obtusely truncated end, the dorsal and ventral margins nearly parallel, and the posterior much narrower and tapered to an obtusely rounded end, with the dorsal margin excavated for the ligamental area. The surface shows distinct but not very prominent grooves and ridges corresponding to the exterior ones; at the anterior end the margin shows slight lobes, corresponding to the intervals between the epidermal digitations. The anterior muscular scar is large and rounded, the posterior one is smaller and subovate. Anteriorly the hinge-margin is thickened iu both valves, running from near the beak nearly to the end; posteriorly it is more strongly thickened by a sinuous callus to which the liga- ment is attached, while under and just in front of the beak the margin is excavated for the reception of the cartilage which continues forward in a groove and is continuous with the broad, dorsal, epidermal mar- gin which unites the two valves throughout their length. The posterior ligament and anterior cartilage appear to blend just beneath the beaks; the commencement of the cartilage is, however, indicated by a slight notch in the call us- margin, iu both valves, and the ligament appears NO. 1139. DEEP-lVATl-:n MOLLUSCA— VERRILL JXD /, r>7/. 887 to extend forward iu a point between the two sides of the cartilage. There are no transverse cost;o or buttresses for strengthening the hiuge- margin. Entire length, including epidermal lobes, 54 in in. ; entire height, oppo- site the beaks, 22 mm.; height of the anterior third, 20 mm.; breadth, in the middle, 12 mm. ; length of longest digitations, about 10 or 12 mm.; length of the shell itself, 42 mm.; height at the middle, 15 inm.; length from beak to anterior end, 30 mm.; to posterior end, 14 mm. Frag- ments of specimens more than twice as large as the one measured have been taken. In one of these the height of the shell without the epider- mis is 25 mm. Two good specimens and some fragments, at four stations, between N. lat. 39° 58' 30", W. long. 70° 30', and N. lat. 37° 24', W. long. 74^ 17', in 300 to 1,000 fathoms, 1S80-1884. EXPLANATION OF PLATES. The figures on Plate IV, fig. 2, Plate VI, figs. 1,2, Plate VII, fig. 9, Plate XXI, figs. 1, 2, and Plate XXV, fig. 8, were drawn l.y Mr. .1. II. Wake. Plate XV, figs. 9, 10, 11, were drawn by Mr. J. H. Kmertou. The other figures are all camera-lucida draw ings by Mr. A. H. Verrill. PLATE LXXI. Fig. 1. Cardiomya f/lypta Bush, p. 810. Dorsal view of type specimen No. 35362; X 10 diameters. 2. Cuspidaria arciica (M. Sars) Dall, p. 803. Interior of a left valve from sta- tion 70; X about 3. Broken outline restored by lines of growth. 3. Cardiomya gemma Verrill and Bush, p. 809. Dorsal view of specimen Xo. 41456; x 10. 4. The s:une. Interior of left valve of the same specimen; x about 13. 5. Ciispidaria media Verrill and Bush, p. 800. Dorsal view of specimen No. 49020; X 5. 6. The same. Interior of left valve of type specimen No. 49018; X 5. 7. Cuspidaria fraterna Verrill and Bush, p. 803. Dorsal view of specimen Xo. 48962; X 5. 8. The same. Interior of left valve of type specimen from station 892; x 5. 9. Ciispidaria gJaciaUs (G. O. Sars) Dall, p. 800. Dorsal view of specimen No. 49023; X 5. PLATE LXXII. Fig. 1. Cuspidaria undata Verrill, p. 798. Hinge of both valves of specimen No. 52517; x about 3. 2. Halonympha si rid tell a Verrill and Bush, p. 810. Hinge of a right valve from station 2655 ; X 25. 3. The same. Turned up to show anterior tooth ; x 25. 4. Myornra ruyinosa (Jeffreys) Verrill and Bush, p. 811. Hinge of right valve of specimen Xo. 52544 ; X about 16. 5. Cuspidaria rentricosa Verrill and Bush, p. 802. Hinge of a right valve Xo. 52548; x 5. 6. Cuspidaria rostrata (Spengler) Dull, p. 800. Hinge of both valves of speci- men Xo. 49067; X 5. 7. Cuspidaria turgida Verrill and Bush, p. 799. Hinge of both valves of type specimen No. 78789; X about 6. PLATE LXXIII. Fig. 1. Cuspidaria subtorla (Sars), p. 806. Hinge of both valves of specimen Xo. 52545; X 9. 2. Cardiomya perrostrata Dall, p. 809. Hinge of both valves of specimen No. 48933; x 22. 3. Cardiomya miiUicostata Verrill and Smith, p. 808. Hinge of both valves of specimen Xo. 48947; X 4i. 4. Cardiomya abyssicola Verrill and Bush, p. 806. Hinge of two separate valves Xo. 78896; X 44. 5. Cuspidaria glacialix (G. O. Sars) Dall, p. 800. Hinge of right valve of speci- men Xo. 49011; X -U. 6. Cuspidaria mrdia Verrill and Bush, p. 80.). Hinge of both valves of type specimen Xo. 49018; X 9. NO. 1139. DEEP-WATER MOLLrSCA—VEHRILL .tXD Jlf'Sff. 889 PLATE LXXIV. Fig. 1. Cardiomya abyssioola Verrill and Bush, p. N06. Exterior of right v;il\e <>t' a young specimen No. 78935 ; x 9. 2. .]fyon<'i-(t myiiiosa (Jeffreys) Verrill and Bush, p.sll. Exterior of righl valve of specimen No. 52544 ; X about 8. 3. Cardiomya pirroalnita Dall, p. JS09. Interior of right vahr of specimen No. TM ':;:); x 9. 4. Cuspidaria sitlitorfa (Sars), p. 806. Hinge of left valve of speeimeu No. 52545; X 9. Turned up to show posterior tooth. 5. The same. Interior of the same valve; x4.l. 6. Cuspidaria formosa Verrill and Bush, p. 803. Hinge of both valves of type specimen No. 78313; X 44. The right valve is badly broken. 7. Cuspidaria arciica (M. Sars) Da'l, p. 803. Hinge of a left valve from station 70; X 4i. 8. Hyoncra limatnla Dall, p. 812. Dorsal view of specimen No. 38171; X 9. 9. (.'ux2>ia>-ra Verrill and Bush, p. 801. Hinge of both valves of type specimen from station 2203; X 30. 10. Cuspidarhi lamellosa (M. Sars) Dall, p. 799. Hinge of both valves of speei- rnen No. 51292; X 30. Resilimn and ossicle are attached in the right valve. 11. Cardiomya gemma Verrill and Bush, p. 809. Hinge of both valves of type specimen No. 41456; X 22. Resilium and ossicle attached in the left valve. PLATE LXXV. Fig. 1. Limopsis minuta (Philippi), p. 846. Hinge of right valve of specimen No. 76320; x 9. 2. Limopsis ajfiiiis Verrill, p. 846. Hinge of right valve of specimen No. 44M".': X 9. 3. Limnpnis aurita (Brocchi), p. 846. Hinge of a right valve from station 2385; X about 11. 4. Limopsis profundicola Verrill and Btish, p. 847. Hinge of right valve of a young specimen No 52410; X 9. 5. Limopsis plana Verrill, p. 846. Hinge of right valve of specimen No. 35238; X 9. 6. Cuspidaria fraterna Verrill and Bush. p. S03. Hinge of both valves of type specimen from station 892 ; X 9. 7. Cuspidaria obesa (Loven) Smith, p. 804. Hinge of right valve of specimen No. 48967; X 9. 8. Cuspidaria peUncida (Stimpsou) Verrill and Bush, p. 805. Hinge of both valves of specimen No. 48977 from Grand Marian; x 22. 9. Cuspidaria f/laciaUs (G. O. Sars) Dall. p. 800. Hinge of right valve of a fully grown specimen No. 49032 to show truncated end of tooth; X 44. PLATE LXXVI. Fig. 1. Foromya subleris Verrill, variety inicrinlonta Dall. p. si:). Kml view of right valve of specimen No. 52533; X 3. 2. The same. Interior of the same; x 3. 3. Cardiomya 'j«nt?a Verrill. p. 811. Hinge of right valve of type specimen No. 35255; X U. 5. The same. Exterior of the same; X 14. 6. Cuspidaria rcntricosa Verrill and Bush, p. SU-2. Interior of a left valve No. 78783; x 3. 890 I' l!0 CEEDINGS OF THE NA TIOXA L M USE UM. VOL. xx. Fig. 7. Cardiomya glypta Bush, p. 810. Hinge of both valves of a young specimen No. 35362; X 22. 8. Citspidaria pellitcida (Stimpson) Verrill and Bush. p. 805. Interior of left valve of specimen No. 48977; X 12. 9. Eatltyarca (tlittxwritnt Verrill and Bush, p. 843. Interior of left valve of speci- men Xo. 78793 ; x 6. PLATE LXXVII. Fig. 1. Macoma Inftata Dawson, p. 778. Hinge of both valves of specimen No. 52429; x 5*. 2. Yuhlhila litcida CLoven) Verrill and Bush, p. 861. Hinge of right valve of specimen Xo. 73173; X about 13. 3. Toldiella subanf/iilaia Verrill and Bush, p. 865. Hinge of left valve of type specimen from station 46 Laclic; x about 13. 4. Cuspiduria furr/ida Verrill and Bush. p. 799. Interior of left valve of type specimen No. 78789; X 4. 5. Myonera (?) pretiosa Verrill and Bush, p. 812. Exterior of a left valve from station 2655 ; X 10. 6. liathyarca pectunculoides (Scacchi) Kobelt, variety svpteiitrionalis Sars, p. 845. Hinge of left valve of specimen No. 74116; X 10. 7. Cusp id art a par- a Verrill and Bush, p. 801. Interior of right valve of type specimen from station 2203; X about 26. 8. liathyarca anomala Verrill and Bush, p. 844. Hinge of right valve of type specimen No. 74081; X 10. 9. Cardiomi/a abyssicola Verrill and Bush, p. 806. Exterior of left valve of specimen No. 52396 ; X 6i. 10. Halonympha xtriatella Verrill and Bush, p. 810. Exterior of a right valve from station 2655 ; X 10. PLATE LXXVIII. Fig. 1. Tindaria oallistiformis Verrill and liush, p. 881. Exterior of right valve of type specimen XTo. 52536; X 6. 2. liathyarca profundicola (Verrill), p. 844. Interior of right valve of specimen No. 52174; X 6. 3. Cnspldarla undata Verrill, p. 798. Exterior of right valve of specimen No. 52547; X 2. 4. The same. Dorsal view of the same specimen. 5. Jlicroyuld'm ri'i/itlaris (Verrill), p. 860. Exterior of left valve of type speci- men No. 38-120; X 20. 6. The same. Interior of right valve of the same specimen. 7. Limopsis ininnta (Philippi), p. 846. Interior of right valve of specimen No. 7i;:;i:0; x 4. 8. Yoldiclla dissimilis Verrill and Bush, p. 872. Exterior of left valve of type specimen Xo. 38416; X 15. PI.ATK LXXIX. Fig. 1. Periploma niidiilata Verrill, p. S2>. Hinge of left valve of type specimen No. 44840; X 7i. 2. Yoldiclla minnsrnhi Verrill an. 870. Interior of left valve of speci- meuXo. 38415; X 22. *. Lain busliiana .Verrill and Smith, it. 851. Exterior of ri^ln \alve of type specimen No. 35729 ; x about:!. 9. Cuspidaria formosa Veirfil and Bush, p. 8(>3. Interior of leit valve of type specimen No. 78313; X 3. 10. Marttxli'Un fi-mi'tUx Verrill and Bush, p. 777. Exterior of right valve of a specimen from near station 2566; X 6. PLAIT. EXXX. Fig. 1. Yohlitlla iris Verrill and Bush, variety xh-irta Verrill and Bush, p. 864. Ex- terior of right valve of type specimen No. 74325; X about 13. 2. Yoldiella iris Verrill and Bush, p. 863. Interior of a left valve from station 895; X 11. 3. Yoldiella liicidn (Loven) Verrill and Bush, p. 861. Exterior of left valve of specimen Xo. 73173; X about 6A. 4. AdraiU'lla casta Verrill and Bush, p. 858. Interior of a left valve from station 2150; X 11. 5. Yoldiella fraterna Verrill and Bnsh, p. 867. Exterior of left valve of type specimen from station 947; X about 13. 6. Tindariti callistiformis Verrill and Bush, p. 881. Hinge of right valve of type specimen No. 52536; X 8. 7. The same. Turned up to show shape of teeth. 8. Yoldiclla inflala Verrill and Bush, p. 864. Exterior of left valve of type specimen Xo. 38417; X about 5|. 9. Yoldiclla lenticnla (Moller) variety amblia Verrill and Bush, p. 866. Exterior of left valve of a specimen from station 186; X 10. 10. Xeilonella suborata Verrill and Bush, p. 878. Exterior of left valve of speci- men Xo. 34826; X 11. PLATE LXXXI. Fig. 1. Ledella pari'a .Verrill and Bush, p. 857. Interior of a. right valve Xo. 78365; X 25. 2. Nuciila granulosa Verrill, p. 853. Hinge of right valve of type specimen No. 38451; X about 16.' 3. JVif specimen Xo. 78958; X about 13. 6. Nucula proxiina Say (f) variety ovatti Verrill and Bush, p. S52. Hinge of right valve of specimen Xo. 7S467; X about 16. 7. Ltdella messanensis (Seguenza) variety sitblevis Verrill andBiish, p. 856. Hinge of left valve of specimen Xo. 35212; x about 16. 8. Xitfiild subocata Verrill and Bush, p. 852. Interior of left valve of type specimen Xo. 40474; X about 13. Showing resilium attached to pit. 9. Lcdi'Ua niesnanenais (Segueu/a), p. 85 i. Hinge of left valve of specimen Xo. 52156; X about 16. 892 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. xx. PLATE LXXXII. Fig. 1. Leda rniidntn (Donovan), p. 855. Interior of right valve of specimen No. 38205; X about 5i. "2. Leda pirnnla (Miiller), p. 855. Hinge of right valve of specimen No. 73077; X ahont 5i. 3. NrUoiu-Ua siiborata Verrill and P.nsh, p. 878. Hinge of left valve of speci- men No. 34326; X about 10. 4. The same. Turned up to show shape of teeth. 5. Yoldiella inliaia Verrill and Bush, p. 864. Hinge of a left valve No. 35575; X about 10. Turned up to show shape of teeth. 6. The ; ame. Front view. 7. Yoldiella. dissimilis Yerrill and Bush, p. 872. Hinge o«f a left valve No. 38416; X 20. 8. Yoldiella fraterna A'errill and Bush, p. 867. Hinge of right valve of type specimen from station 947 ; X 20. 9. Leda biishiana Verrill, p. 854. Hinge of both valves of type specimen No. 35729; X about 6L 10. Malletia polita Verrill and Bush. p. 876. Hinge of a left valve No. 78792: X about 6i. Some of the teeth are broken away just behind the beak. 11. Yoldiella iris Verrill and Bush, p. 863. Hinge of left valve of a young- specimen; X 20. PLATE LXXXIII. Fig. 1. Crenella fray His Verrill, p. 847. Interior of right valve of type specimen No. No. 41543; X about 3. 2. The same. Hinge of another larger, imperfect specimen No. 40676 ; X about 3. 3. Yoldiella jeffreysi (Hidalgo), p. 866. Exterior of a left valve No. 78958; X about 13. 4. Llmopsisprofundlcola Verrill and Bush, p. 847. Interior of a right valve of a young specimen No. 38143; X about 3. 5. Nucula stiborata Verrill and Bush, p. 8">2. Exterior of left valve of type specimen No. 40476; X about 13. 6. Abra lont/icallis (Scacchi) variety ameriouia Verrill and Bush, p. 778. Inte- rior of right valve of specimen No. 52170; X about 3. 7. The same. Hinge of both valves of the same specimen; X about 8. PLATE LXXXIV. Figs. 1 and 2. Chlamys benedicli Verrill and Bush, p. 834. Exterior of both valves of a young specimen found among For;iminifera ; X 20. PLATE LXXXV. Fig. 1. Cyclopecfen leptah-us Verrill, p. 839. Portion of upper or left valve of type specimen No. 38413 to show character of sculpture; x 10. 2. Cyclopecten natms Verrill and Bush, p. 837. Exterior of lower or right valve of a young specimen from station 2265; x 5. 3. The same. Exterior of left valve of a larger specimen from the same station ; x 5. 4. The same. Hinge of the same valve; X 13. 5. Cyclopecten pmtulosux Verrill, p. 839. Portion of left valve of specimen No. 48765 to show character of sculpture; X 10. 6. The same. Piece of a left valve of another specimen No. 48761 to show vari- ation in form of pustules; X about 13. 7. Camptonectes grocnlandica (Sowerby) Verrill, p. 837. Exterior of right valve of specimen No. 78387; X 5. NO. 1139. DEEP-TTJTER MOLLUSC A— VElllllLL AXD JiU*H. 893 Fig. 8. Cyt.-lopei'tcH snl>i»iln-ij\ r Verrill and Bush, p. 840. Portion of left vjilve of specimen No. 4N762 to show ehararter of sculpture; X 10; 9. The same. Exterior of left valve of specimen No. isTliti from oil' Nova Scoiia, in 190 fathoms; X 3. 10. Cyclopectenpustulo8U8'VerTill,'p.839. Exterior of left valve of type specimen No. 48761; x 3. 11. The same. Exterior of right valve of another specimen ; x '••• PLATE LXXXVI. Fig. 1. Solemya grand is Verrill and Bush, p. N85. Exterior of left valve of type specimen No. 51345; x 14. 2. The same. Interior of right valve of an imperfect specimen No. 40103; X H. Epidermal fringe restored from other specimen. 3. Cryptodon (Ajciniilus) pyymnns Verrill and Hush, p. 792. Exterior of left valve of specimen No. 783b'8 from station 2697; X 22. 4. The same. Interior of right valve of a smaller specimen from the same station; X 22. 5. Niicula canct'Uata Jeffreys, p. 854. Exterior of left valve of specimen No. 45795; X 12. ti. Chlainys coxtrUata Verrill and Bush, p. 835. Exterior of right valve of type specimen No. 52471 ; X 9. PLATE LXXXVII. Fig. 1. Poromya sublet- is Verrill, variety microdonta Dall, p. 813. Hinge of a left valve No. 78799; X 5. 2. rerticordid f/rainilifcra (Verrill) Dall, p. 816. Interior of a left valve (type specimen) No. 44838; x 4. 3. Lyonsiella subquadrata (Jeffreys), p. 817. Interior of a left valve No. 78800; X 10. 4. Pvriploma ajfinis Verrill and Bnsh, p. 822. Exterior of right valve of type specimen from station 873; X 4. 5. I'eripJoma ntidnUtta Verrill, p. 823. Exterior of left valve of type specimen No. 44840; x 4. 6. PropfamusiiiM ihahissiniim (Dall) Verrill, p. 841. Exterior of upper or left valve of a specimen from station 949; X 16. 7. Cryptodon ( Ajcinnlns) fcrruyinosits (Forbes), p. 793. Interior of right valve of specimen No. 34860; x 12. 8. The same. Interior of left valve of the same specimen. PLATE LXXXVIII. Fig. 1. Cryplodon croulinensis (Jeffreys) Smith, variety altus Verrill and Bush, p. 787. Exterior of a left valve from Eastport, Maine, 1870; X about 8. 2. The same. Interior of a right valve from the same locality; X about 8. 3. Cryptodon planux Verrill and Bush, p. 788. Interior of left valve of type specimen from station 254 ; x 14. 4. The same. Exterior of right valve of the same specimen. 5. Nucula proximo Say (?) variety orata Verrill and Bush, p. 852. Exterior of left valve of specimen No. 73467; X about 12. 6. Macoma In flat a Dawsoii, p. 778. Exterior of left valve of specimen No. 52427; X 3. 7. fit-nnerUa breris Verrill and Bush, p. 821. ti. Exterior of left valve of speci- men No. 40232; b, interior of right valve of another specimen No. 45884; X 4. 8. XucitJa (/ranuliitut Verrill, p. 853. Exterior of left valve of type specimen No. 38451; X about 26. 894 PL'OCEEDIXGS OF THE XATIOXAL MUSEUM. VOL. xx. PLATE LXXXIX. • Fig. 1. Cryptodon obsoletus Verrill and Bush, p. 789. Exterior of right valve of a specimen from station 949; X about 20. 2. The same. Interior of left valve of the same specimen. 3. Leptaxinns miiuitu* Verrill and Bush. p. 797. Hinge of left valve of type specimen No. 45686; X 45. 4. The .same. Hinge of right valve of the same specimen. 5. The same. Interior of the same valve ; x 30. 6. Cryptodon plicatus Yerrill, p. 786. Interior of left valve of a young specimen No. 44826; X 9. 7. Cryptodon (Axinulus) breris Yerrill and Bush, p. 790. Exterior of left valve of type specimen from station 2208 ; X about 22. 8. The same. Interior of right valve of the same specimen. PLATE XC. Fig. 1. Cryptodon (Axinulus') inequalis Yerrill and Bush, p. 791. Exterior of right valve of type specimen from stations 98-99; X about 10. 2. The same. Interior of left valve of the same specimen. 3. Cryptodon croulinensis (Jeffreys) Smith, p. 786. Interior of left valve of a specimen from stations 62-65 ; X about 13. 4. The same. Exterior of right valve of the same specimen. 5. Axinodon cllipticiis Yerrill and Bnsh, p. 796. Exterior of right valve of type specimen No. 35175 ; x about 13. 6. The same. Interior of left valve of the same specimen. 7. TelUmya ferruginosa (Montagu), p. 783. Interior of left valve of specimen No. 49588; X 20. a, Cartilage. 8. The same. Interior of right valve of the same specimen. PLATE XCI. Fig. 1. Cryptodon insignia Yerrill and Bush. p. 785. Interior of a left valve No. 52733 from station 2499; X about 14. 2. The same. Exterior of a left valve from the same station; x about H. 3. Montucittn ti'iquetra Yerrill and Bush, p. 782. Interior of right valve of type specimen from station 2307; X 24. 4. Moiitai'iila cuneata Verrill and Bush, p. 782. Exterior of right valve of a specimen from station 2278; X 17. 5. Cryptodon equalis Yerrill and Bush, p. 788. Hinge of both valves of a speci- men from station 18 Jiacltc; X about 5. 6. The same. Exterior of left valve of specimen No. 74302; x about 5. 7. Cryptodon (Axinulus) ot'atus Yerrill and Bush, p. 793. Interior of left valve of type specimen from station 949; x 35. 8. KeUleUa nitida Verrill, p. 778. Interior of left valve of specimen No. 37971; X 14. PLATE XCII. Fig. 1. Axinodon dlipticus Yerrill and Bush, p. 796. Hinge of left valve of type specimen No. 35175; x about 26i. 2. Limopsis sulcata Yerrill and Bush, p. 845. Interior of a right valve from station 2199; X 4. 3. Cryptodon (Axinulus) simplex Yerrill and Bush, p. 791. Hinge of right valve of type specimen from station 1093; X about 13. 4. The same. Interior of left valve of the same specimen. 5. Axinopsis orbiculata Sars, variety inequalis Yerrill and Bush, p. 794. Interior of left valve of type specimen from Eastport, Maine, 1872; X about 13. NO. 1139. DEEP-WATER MOLLUSCA— VERRILL AM> I'.rsll. 8i>") Fig. 6. The same. Hinge of both valves of the same specimen ; x aliout 26. 7. Montacuta bidcntata (Montagu) variety tenuix Verrill ;md Bush, p. 779. Interior of a right valve 1'roui station 2277; X about 13. 8. Montacnta bidcntata (Montagu1) variety fnt'/ilis Verrill and Bush. p. 780. Inte- rior of a right valve No. 4l>134; X 17. 9. Montacuta orata Jeffreys, p. 7*1. Interior ol' a right valve No. 461)56: x 20. 10. The same. Interior of a left valve No. 46137; X 20. PLATE XCIII. Fig. 1. Cri/Dfodoii (Axinulus) oratits Verrill and Basil, p. 793. Hinge of lioth valves of type specimen from station 94!) ; X 45. 2. Kelliopsia elcvata (Stimpson) Verrill and Bush, p. 7*4. Hinge of a right valve No. 74333 from Nanshon ; X 30. o, Resilium and ossicle. 3. The same. Hinge of another right valve from the same station, to show variation; X 30. 4. The same. Hinge of both valves of another specimen from the same station; X 30. 5. Montacuta cuneata Verrill and Bush, p. 782. Hinge of both valves from station 2278; X 30. 6. Moutacuta tttmidula Jeffreys, p. 781. Hinge of a left valve No. 35412; x 30. a, Resilium and ossicle. 7. Monlacnia bidentata (Montagu), p. 779. Hinge of a right valve No. 74328 from Naushon ; x 30. 8. The same. Hinge of both valves of a smaller specimen from the same sta- tion ; X 30. 9. Montacuta striatula Verrill and Bush. p. 780. Hinge of a left valve 1'roai station 2276; X 30. Hinge of a right valve from station 2273; X 30. 10. KeUieUa nitida Verrill, p. 778. Hinge of both valves of specimen No. 37971; X 12. Right valve turned down, left turned up PLATE XCIV. Fig. 1. Montacuta tuntidula Jeffreys, p. 781. Interior of a left valve No. 35412 from station 2103; X 20. a, Resilium and ossicle. 2. The same. Interior of a right valve from the same station; X 20. 3. KeUia suborbicularis (Montagu), p. 779. Interior of left valve of a specimen from off Salem, Massachusetts, 1877; X 10. 4. The same. Interior of right valve of the same specimen. 5. Montacuta casta Verrill and Bush, p. 781. Exterior of a left valve from sta- tion 2283; x 20. 6. Montacuta bidentala (Montagu), p. 779. Interior of a right valve No. 74328; X about 13. 7. Kelliopsis elevata (Stimpsou) Verrill and Bush, p. 784. Interior of a right valve No. 74333 from Naushon; X about 13. «, Resilium and ossicle. 8. The same. Exterior of a left valve from the same station; x about 13. PLATE XCV. Fig. 1. Lyonsia yranulifcra Verrill and Bush, p. 818. Exterior of a left valve (type specimen) No. 52561; X about 2A. 2. rerticordia gran itlif era (Verrill) Dall. p. 816. Hinge of a left valve (type specimen) No. 44838; x 8. 3. The same. Hinge of both valves of a fully grown specimen No. 78679; X 4. Turned up to show ossicle, a. 4. The same. Hinge of a right valve of another specimen No. 78929; X 6A. sin; I'!:.;/ clintoniiis 831, 838 costellata S35 islandica 827,834 varia 8:14 ( 'In iris todon ? eanci-llatus r , "^ Clausina croulineusis 78ft Clidiophora 77H gouldiana 820 inornata s'J.'/ t rilineata 820 Crenella f ragilis 847 Cryptodon 776, 784, 785, 795, 797 ( Axinulus) brevis 799 crouliiH-nsis '86 var. altus -7 equalis 7w (Axinulus) ferruginosus 7.''-.'. 7!li tlcxiiosus 784,788 897 898 I'HOCEEDINGS OF THE NATIONAL VOL. XX. Page. Cr\ ]>tiirlon gouldii 787, 788 grantlis 7S5 (Axinulus) inequalis 731 insignia 785 obsoletns 780 ( Aximilns) ovatus 703 plauus 7*88 plicatus 7S6 ( Axiuulus) pygmanis 702 sarsii 785, 786 ( Axinulus) simplex 701 su'novatus 793 tortuosug 793 Cryptodontiilii- 784. 851 Ctenodonta 850 CtenodontidsR 850 Cucullaria 842 lieterodonta 842 Cucullellinse 851, 880 Cuspidaria 776 arctica 800, S"3 var. glacialis 800 formosa 803 fraterna 801, 802, 803 glacialis 799, SOO, 801, 802 lamellosa 709 media 800 obesa s 801, 802, 803, 804 parva , SOI pollucida -. .905 rostrata 799, SOO sulitorta 806 turgida 709 undata 7 '.iff ventricosa SOS Cuspidarida? 70S Cyamiiim elevatum 784 Cyclopecten. (See also Pecten) 776. 829, 832 imbrifer 832, 839, 840 kermadecensis 841 le.ptaleus 839 iianus 837 pustulosus 832, 839 subirubrifer 840 Dentipecten 827 Piplodoutidse 784 Eryc-inidae 779 Felipes 833 pesfelis 833 Flabellipecten 833 flabelliformis 833 Flexopecten 833 flexuoaus 833 Gloniida? 847 (iloniin:f 847 Ginning 547 inaequilateralis 848 japonicus 848 Jeffreys! 848 iiitens 847. 348 simplex 848 Halonympha 776, 798 rlaviculata 811 striatella S 10 Hemipeoten s'.'s forbesianua 828 Page. Hinnites $27, 828. s.'J3 Himiites cortessi 827 Hyalopecteu. (See als > Pecten) 776, $32 dik-ctus 832, 836 fragilis 832. 936 jmdicus 832, 836 undatus 832, 836 Janira 826 Junonia 855, 884 Jupiteria 884 Kellia 783 suborbicularis 779 Kelliella nitida 778 sp 778 Kellk-llidse 778 Kelliopsis 776, 7 $3 elevata 784 Kennerlia 776. 822 bre vis 821 glacialis 821,822 Leda 776, 849, 850, 852, 854, 857, 877, 878, 884 acuniinata 856 Inisliiana 854 caudata 854, 855 cuspidata 854 expansa 871 fluviatilis 854 Jeffrey si 866 lata 866 lenticula 866 lucida 801 messanensis 856 obesa 861, 863 pernula 854, 855 portlandioa 857 rostrata 854 subequilatera 871 teiiuisulcata 854 Ledella 776, 855, 884 coufini.s 856 coufnsa 856 iuopiuata 856 messaneusis 855, s.'i] var. snblevis 856 nicotr;e 855 parva s\"r peraffinis 855 prolata 856 rectidorsata 856 semen 856, 857 seminula 855 solidula 856 ultima 856 Ledidit S4S, 851, 854, 884 Ledinse 851, 854, 884 Leptaxiims 776, 70G miuutus 796, 707 Lcjiionida? 779 Leptopecten. (See also Pecten) 831 mouotiineris 831 Limit? a pubovata 824 Limatula 776 confusa 825 hyalina 825 nodulosa 824 regularis S23 NO. 1139. DEEP-WATER HOLL USCA— YEURILL AM> 1',1'sII. 899 I'age. Limatula aubovata 824 Moutamiu runt-ata Limida- 823 \ > Irvata 783,784 Limopsida:1 845 , tViTiiginusa 783 Lhuupsis 776,851 ovata 7 si allinis •>'/'•' striatula 7-,n aurita S4G triquetra 782 var. plana 84C tnmidula 781 var. .' 847 Mya bidcntata 770 minuta ^4 •' Myouera 776, 798 plana *-/'•' gigantea 811 profundicola 847 ; limatnla 81) sp 846 paucistriata 809 snlcata tH-' prt-tiosa s;.: Liropecten 829 rnginosa 811 Lissorhlamys 833 undata 798 excisa 833 Mytilida- 847 Lissopecteu. (See also Pecten) id.> .Neivra arctica 803 kyalinus 830 ; costata 810 Lyonsia 776 gigautea 811 arenosa 819 jilacialis 800 granulifera 818 laiuellosa 799 Lyonsidae 818 ; limatula 812 Lyonsiflla 776 inulticostafa 808 cordata $1* var. cnrta 808 subquadrata 817 obesa 804,805 Lyonsiellidae 817 pauristriata 809 Lyrodesiua 851 pellucida 804, 805 Lyrodestnatinae 851 perrostrata 809 Lyro]iecten. (See also Pecteu) 829 rostrata 800 nodosus 829 ruginosa 811 ilacoma 776 sp 805 inflata 778 anbtorta 806 Mai-rochlamys 833 undata 798 latissima 833 Neilo S77, 885 Macrodon 842 cuiningii 877 asperula 842 goniura 877 profundicola 844 Neilonella 776,577,885 sagrii.ata 842 corjnilenta 877, 878 Malk-tia 776, 850, S73, 878, 880, 885 pnsio 878 abyssorum 874,, 884 , adamsi 851 regularis SCO ealabra 8.51 Moutacnta 776,783 ntiliari* 851 bidentata 779,784 numita . 851 var. t'ragilis ,'v* ovalis 851 var. tennis , ;;- sulcata 851 bowmani 780 Xncnliiiii- 884 casta :^i Xuculites 850 900 PEOCEED1NGS OF THE NATIONAL MUSEUM. VOL. xx. Page. Page. Oopecten 833 Feri])lonia affiuis 822 o.,pcctcn rotundatua 833 umlulata 823 Orthoyoldia 859,885 Periplomida- 822 scapina 859 Petricolida- 77X snlt-noides 859 Pbascolus 851,884 Pala-nneilo 849.850,851 ovatiis 868, .S84 constricta 850 Pholadidie 777 plana 850 Placopecten. (See also Pecten) 831 Palliolum. (See also Pecten) 828,523,833 cliutonins 831,838 striatmu 828 Pleurodon 851 test* 829 Pleuronectia 82U vitreuni 829 Pororuya 776 Pallimn. (iSVe also Pei-teii> 6'2,v. 829 (Cetomya) elongata 815 plica 827 granulata 815 Pandora 821,822 microduuta 813 rostrata 822 sublevis 813 Paudorida.' 819 var. microdouta S13 Paramusium S32 Poromyida- 813 dalli 832 Portlandia 857, 859. 884 Parvamussinm 833 :nvtica 857 cauc.'llatiim 833 lenticula 8G6 Peccliiolia jii'auulifera 816 lucida 862 subquadrata :. 817 Propeamusiuui. (.Set1 also Pecteu) 829, 833 Pecteii 526,827,833 fenestratum 829 beuedicti (Chlaniys) SS4 hoskynsi 839 clintonius (Placopecten) 831,838 "inequisculpta 829 costellatus (Chlamys) 835 tbalassinnm S41 dilectus(Hyaloperten) 832,53(7 Pseudamusium. (»S'e lil'SH. 901 Page. Tindariopsis SS3.885 Tindariopsia ajathida 883 Trigoiiiada- 851 TTngulinidci' 734 Verticordia granifera 816 granulifera S16 Verticordida' 816 Vesicornya 817 Tola 826 Toldia . . . 849, 850, 851, 852, 854, 857, S5S. 859, 878, 884 abyssicola 866 arctica 358 expausa 871,87-2,873 frijjida 867, 868, 872 hyperborea 858 Jeffreys! 866, 870 limatiila 858 lurida 861,864 nn'nsaiieiisis, var 856 niyalis 858 obesa 801, 863 obtusa 874 regularis 860 I':.-, Toldia sapotilla 858 sericea 879 var. striolata 878 snbeqtulatera 871 Toldiella 776, 849. sCl, 885 curta 861. .^;s', 869 dissimilis 8t',l -. expansa 8'. / fraterna 8tii. ?67 frigida H;I. S7S hoy lei Mil incoiispiiMta S61 . v . . iiiflata 861, 8C,:: iris s<; ; var. stricta *m M;I Jeffrey si 861 . v .-. lenticula Siil var. amblia 801. Ji • lucida .•>•';;. ssr, miuuscula 801 970 pachia 8til •< • subangulata 861 . - subequilatera 801.>,"J 0. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXI 2 X10 X3 xio X13 X5 X5 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 888. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXII 4 / DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 888. U. S. NATIONAL MUSEUM PROCEEDINGS. VOL. XX P^. LXXIII DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 888. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXIV X9 X30 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 889. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXV X9 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 889. U. S. NATIONAL MUSEUM PROCEEDINGS VOL. XX PL. LXXVI X12 xe DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGES 889, 890. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXVII 2 xio DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 890. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXVIII X6 X20 X2 X4 X20 X2 X 15 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 890. U. S. NATIONAL MUSEUM 1 PROCEEDINGS, VOL. XX PL. LXXIX DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SFE PAGES 890, 891. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXX 3 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 891 . U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXXI DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 891. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXXII 3 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 892. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXXIII DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 892. U. S. NATIONAL MUSEUM PROCEEDINGS VOL. XX PL. LXXXIV X20 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 892. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXXV Jmmmmz± xsV *>• K7$ '•< O^- " r?. i / » ' I ' - -i.'T'V V- •— A-^t S-*Tf 3 -I.' '•>'•> i S- '-% ' ^V " "vl- ' • DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGES 892, 893. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXXVI DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 893. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXXVII X4 X1G X4 X10 X12 X12 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 893. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXXVIII 2 X8 X8 XU X12 X3 X26 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 893. I). S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. LXXXIX X20 X20 X22 X22 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEF PAGE 894. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. XC X13 X13 X20 X13 X20 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 894. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. XCI X17 X24 X35 X14 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 894. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. XCII 2 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGES 894, 895. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. XCIII DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE Sf E PAGE 895. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. XCIV X20 X10 X20 X10 X13 X20 X13 X13 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 895. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. XCV DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGES 895, 896. U. S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. XCVI X16 i X6 DEEP SEA BIVALVES. FOF< EXPLANATION OF PLATE SEE PAGE 896. U S. NATIONAL MUSEUM PROCEEDINGS, VOL. XX PL. XCVII X20 DEEP SEA BIVALVES. FOR EXPLANATION OF PLATE SEE PAGE 896.