oes Kirncrrate en, ~ % TED, Wiss JSTIRA COMPRISING FRENCH EDITION, Fx re) Z fe) Leal ee Ce A | im mM Ls | | i] a | A 4 ¢q a 4 to} q i a ié) HE WHOLE OF THE RECENT ADDITIONS IN DESHAY gets tee ett pe Ng tore Men Pp Vth Pe vem ; ame acai i DP th ee th ores peat s Se a sea magia oa ear ee weet = ie en ee ee hee 4 Rin thate—nHard fis far eel Si 2 2% us lt * S 7 oF ? nes 1 Py “Ue Outten fiwne | amy fix hineong La Loew Pia wen > icomeanaoms CunnarTa.—Awnatina CO. Gray... Spic.. Zt. 3... fs 14. Solid, irregular, subequivalve, oblong-wedgeshaped, anteriorly pro- duced, posteriorly very short, subtruncated and rounded; with irregular concentric wrinkles, pearly within ; periostraca hard, greenish, extending beyond the margin; hinge almost toothless, with a large moveable oblong tooth-like appendage. }..13.— Peru. 26 TESTACEOUS MOLLUSCA. Section TENUIPEDES. The mantle barely united before ; foot small, and compressed ; shell having but a moderate gape. TRIBE MACTRACEA. Equivalve shells, frequently gaping at the lateral extremities ; with an internal ligament, or partly external, and the animal having a small compressed foot. LUTRARIA. Inequilateral, transversely oblong, or rounded, gaping at the ex- tremities ; hinge with one tooth, which is somewhat complicated, or two teeth, of which one is simple, with an adjoining deltoid hollow, which is oblique, and prominent within; no lateral teeth ; ligament internai, attached to the cardinal pits. * Transversely oblong. L. Sorenorpes. Lam. 1.—Bl. t. 77. f. 3.—Son. G. f. 1.— Mya Ostonea. Gm. 3221.—Mactra Hyans. D. p. 146.— Mont. p. 101.—Don. t. 140.—Ch.f. 12.—W. t. 16. f. 37.—L. Ostonea. Turt. B. p. 64. t. 5.f.6. Oblong, the posterior side short and rounded, the anterior produced and obtuse, margins nearly parallel, the dorsal slightly incurved ; yellowish-white or rufous under a thick epidermis, with irregular rugged transverse strie ; hinge with a grooved, flattish, tooth, locking between two others in the opposite valve. 24.—Hurope. L. Exvurptica. Lam. 2.—Turt. B. p. 65.—Mactra Lutra- ria. Lin. Gmel.3259.—W. t. 6. f. 36.— Mont. p. 99.—D. p. 145. —Tist. t. 415. f. 259.—Ch. f. 240, 1.—Don. 2. t. 58. Oblong, nearly equivalve, marked only with the lines of growth and remote obsolete ridges, anterior side the longer, rounded and slightly gaping at both ends, yellowish white under a thin close cuticle. 2..34.— Hurope. L. Rucosa. Lam. 3.—Mactra Rucosa. Gimel. 3261.—D. ptAS = Ch. of. OBbr 7 Ee pa ee eb og an Transversely ovate, yellowish-white, marked with strong longitudinal and obsolete transverse striee, except at the extremities which are smooth and somewhat glabrous.—Lurope. L. Eeyeriaca. Gray.—Macr. E. D. p. 145.—Ch. f. 1955, 6.—W. ¢t. 6. f. 34. Oblong-oval, obtuse at the extremities, ven- tral margin little curved; white under a yellowish epidermis, longi- tudinally striated. 1..¢.—Red Sea. L. Exoneata.— Gray. Mag. Nat. 1837. Elongated, ovate- TRIBE MACTRACEA. 27 lanceolate, solid, white, tapering anteriorly oblique: slightly gaping anteriorly; a distinct lozenge, edged with a raised line ; anterior lateral teeth wanting in the adults. —Pr ince of Wales Island. L. Ensts. Quoy. Ast. t. 83. f.5, 6. Elongated-ovate, narrow, transverse inequilateral, arcuated, yellowish-grey, with irregular transverse grooves ; anterior side rounded and very short. 3.—W. Zealand. * * Orbicular or sub-triangular. L. Compressa. Lam. 4.—L. Preerata. Lam. 5.—BI1.t.77. f. 2.—Macrra Prrerata. Gmel. 3261.—D. p.142.—Ch.f. 21. — HE. t.257. f.4,—M. Listerr. W.t. 6. f. 25.—Treviina PLana. Don. t. 64. f. 1.—Lieuta C. Mont. p. 96.—Lisrera C. Turt. B. p. 51. t. 5. ff 1. Thin, compressed, triangularly rounded, yellowish-white, finely but irregularly striated transversely, semi- pellucid; beaks very small and central; a distinct lozenge, edged with a raised line ; a single tooth in one valve looking into a bifid one in the opposite, no lateral teeth. 14...1}.—urope. L. Tevurnoipes. Lam. 6.—Deles. t. 3. f. 5. Ovate, sub- triangular, thin, pellucid, white, with fine, unequal, transverse, striz; posterior side short, obliquely truncated, and somewhat plaited. 1. — Guinea?! L. Canpipa. Lam.7. Ovate, thin, pellucid, white, with un- equal transverse strize : posterior side the longer. L. Papyracea. Lam. 8.—Sow. G.—Reeve, t. 41. f. 2.— Macrra Recurva. W.S.f. 2.—An. L. Lingata. Say. Am. Conch. t. 9. Roundish-ovate ; thin, pellucid, transversely striated, with very fine longitudinal striz in an isolated place near the anterior side, which is widely gaping and marked with an elevated longitudinal line on each valve.—Indian Ocean. L. Putcaretta. Lam. 9.—An. Mactra Papyracea Gmel. 3257 ?—D. p. 133 ?-—Ch. f. 231? Ovate-rounded, thin, pellucid, white, with numerous fine transverse plaits ; anterior side short and sub-angulated.— VV. America.* 1 This species is in all probability the Tellina Angulata of Lin- nzeus, whose own specimens are undoubtedly Lutrarie. I have given copies of Delessert’s figure of Tellinoides and Wood’s Angulata. T. ANcuxtata. Lin.—Ch. f. 75.—D. p. 75.— Wood, G. C. p. 146. t. 43. f. 1.— W.t. 3. f. 5. Triangular-ovate, anteriorly much shorter, bent and angulated ; white, sub-inflated, nearly smooth, ven- tral edge but little curved, ligament very small ; no lateral teeth. * It is not absolutely impossible, that this at present rather doubt- ful species, may prove to be identical with the L. Canaricuntata. Say Jour. A. N. S. Phil. 2. p. 311.— Macrra Camprecuensis. Gray in W. S. t. 1. f. 3.—An. 28 TESTACEOUS MOLLUSCA. L. Crassrprica. Lam. 10.—An. variety. E. t. 255. f. 21 Rounded-ovate, thin, pellucid, white, convex, with tolerably large and regular transverse plaits; posterior side very short. 14.— Indian Ocean? L. Compranata. Lam. 11.—Macrra C. Gmel. 3261.—W. t.6. f. 35.—M. Puanara. D. p. 145.—£. t. 258. f. 4.—Ch. f. 238. Ovate-oblong, thin, finely striated and ridged transversely, compressed, hinge margin nearly straight ; anterior lateral teeth very distinct and simple in each valve. 11.—Indian Ocean. L. Corrarpit. Payr. p. 28. ¢t. 1. f. 1, 2.—Phil. p. 10. Triangularly oval, compressed, pellucid, shining, sub-equilateral, posterior side sub-angulated, anterior rounded; white with fine transverse strize, umbones acute and very small; ligamental pit oblique and very small ; teeth obsolete.— Mediterranean. L. Virrea. Gray.—Macrra V. D. p. 133.—Ch. f. 1959, 0.— W.t. 6.7.4. Ovate somewhat heart-shaped, very brittle, white, diaphanous, transversely plaited ; anterior depression lanceolate, posterior ovate oblong ; hinge much nearer the posterior end. 1..14. —Coromandel and Ceylon. L. Sauamosa. Gray.—Sotren 8. Mont. p. 565.—D. p. 70. -—lEPton S. Lurk: Bw. p. 62. 7. 6.7. 1, 2, 3. .chlatimeanly orbicular, equivalve, inequilateral, pellucid, thin, white, obscurely wrinkled, concentrically punctured in a scale-like manner, beak small and pointed. 54,..,9,.—England, rare.} MACTRA. Transverse, inequilateral, subtrigonal, sides slightly gaping : beaks prominent : one primary compressed V-shaped tooth in each valve and an adjacent heart-shaped cavity ; tivo lateral com- pressed teeth, situated near the hinge and inserted ; ligament internal and inserted in the pit of the hinge. M. Soxrpissima. Chem. f. 1656.—D. p. 140.—Gould. Mas. List. t. 308. f. 141. Transversely oval-orbicular, very thin, white, inflated, equally concentrically and regularly grooved, with very faint parallel lines within the grooves, posteriorly short, sub-cunei- form, compressed ; a marginal, longitudinal, irregular, sub-impressed line, between which and the edge the grooves become mere wrinkles; posterior dorsal edge straightish, the gape considerable; anteriorly regularly curved, the slope convex. 2..23.—U. States. ?Add C. Cyprinus. Gray. W.S.t.1.f.1. See too L. Lin- EATA. Say. Am. C. t.9,—L. (CrRypropon) Nutra. Conrad. Jour AGN Sean, Fn teal TRIBE MACTRACEA, 29 —W. t.6.f.22.—M. Gieantra. Lam. 1.—E. t.259. f.1. Solid, oval, subtriangular, nearly smooth; under a thin whitish or yellowish epidermis, pale fulvous, opaque, the ventral edge little arcuated, slopes smooth ; hinge nearly but not quite central, the lateral teeth cross ribbed and elongated. 4.—New York. M. Sreneieri. Lam. 2.—Gmel. 3256.—D. p. 132.—Ch. f. 199, 0, 1.—#. t. 252. f. 3.—Reeve. t. 42. f. 1.— Son. G. f. 1.— Pt AGS EXT. Triangular, smooth, both slopes flat; the anterior chiefly so, subdiaphanous, pale brownish ; beaks distant, separated by a transverse crescent-shaped gap, which contains the ligament. 2..3.—Cape of Good Hope. M. Srriatrevta. Lam. 3.—H. t, 255. f. 2. Large, pellucid, convex, white, anterior slope obliquely striated, bounded by an obtuse angle ; beaks substriated ; lateral teeth ahiont and smooth. — India. Larger but bearing some resemblance to the next. M. Srriatusa. Lin. 1125.—D. p. 133.—Kn. 6. t. 34. fi 1.— M Carinata. Lam. 4.—JH. t. 251. f. 1.—M. Avata. W.S. f. 7. Triangular, pellucid, white, convex; beaks smooth; hinge rather nearer the posterior than the anterior side which is bounded by an elevated plate with raised angles; anterior lateral tooth small and close, the posterior elongated.—. Indies ? M. Guauca.* Gmel. 3260.—D. p. 144.—W. t. 6. f. 30.—Ch. _ f- 232.—M. Hetvacea. Lam. 5.—NeEapouirana. Poli. t. 18. f. 1, 2, 3. Triangularly oval, dirty white rayed with fulvous becoming by age of an obscurely rayed red colour, rather depressed, striated transversely ; beaks not quite central, smooth, and recurved, with a narrow gape beneath them. 2}..3} .—Spain and Italy. M. Stutrorum. Lin. 1126. = p. 138.—Lam. 7.—Ch. f. 224, 5.—Mont. p. 94.—Turt. B. p.72.—E. t. 256. f. 3.—Don. t. 106.—W. ¢. 6. f. 18.—Tewuina Rapiata. Pen. 4. p. 87.t. 49. f. 30. Ovate triangular, thin, slightly depressed from the beaks at each extremity, subdiaphanous, nearly smooth, pale fulvous with obsolete white rays; peas nearly central, and, as well as the interior, purplish red. 1}..13.—Hurope, the Atlantic.2 2 M. Granois. han 6.—Gmel. no. 12.—D. p. 139.—E. t. 253. f.1.—Ch. f. 228.—W. t. 6. f. 19. Triangular, anteriorly the more produced and subrostrated, smooth, fawn colour with paler rays ; beaks tumid and violet-brown. 24..31.—Nem Jersey ? M. Macunosa. Lam. 8.—M. Ornata? Gray in Mag. N. H. 1837. Triangularly oval, livid rufous, speckled with white, and marked with paler rays, smooth, subinequilateral ; beaks and sides 2 The M. Cinerea* of Montagu, Pennant and Turton differs in being proportionately broader, of a pale drab with sometimes one or two obsolete white rays and never lilac internally. 30 TESTACEOUS MOLLUSCA. purplish : within, with three purple spots on the dorsal edge. 13.— China ? M. Niripa. Schroeter, vol. 3. t. 8. f. 2.—D. p. 136.—W. t. 6. f. 13.—M. Srraminea. Lam. §. Triangularly ovate, smooth, shining, diaphanous, white scarcely if at all rayed ; beaks obsoletely rufous: ligament external, in an oblique triangular groove. 13.— Cape of Good Hope. M. Guasrata. Lin. 1125.—D. p. 136.—W. t. 6. f. 12.—M. Austrautis. Lam. 10.—Ch. f. 216, 7. Triangular, thickish, diaphanous, glabrous, finely striated transversely, tawny white : umbones very smooth ; interior with two or three purple stains. 21..3.—New Holland. M. Viouacea. Gmel. no. 18.—D. p. 135.—Lam. 11.—Ch. f. 213, 4.—#H. t. 254. ff 1.— W.t. 6. f. 9. Triangularly ovate, sub- equilateral, thin, diaphanous, nearly smooth, violet within and without, but darker at the beaks and paler on the depressions of which the anterior is lanceolate, the posterior oblong, anterior lateral tooth short and approximate. 24..3.— Tranquebar. M.Fascrata. Lam. 12. Gualt.71. B. (tolerable) Triangular, ventricose, thin, smooth, subdiaphanous, white with distant violet zones ; anterior slope striated and very pale ; violet within ; variety ; with pale fulvous rays.—Atlantic ? M. Tureipa. Gmel. 3260.—D. p. 134.—Lam. 13.—Ch. f. 210, 212 —E. ¢. 255. f. 3.—W. t. 6. f. 8. Triangularly ovate, ven- tricose, thin, smooth, pellucid, pale ochraceous, finely striated, transversely and wrinkled at both ends; umbones incurved and pale reddish purple; within, white with a large purple stain under the hinge. 2..23.—T'ranquebar. M. Puicatarta. Lin. 1125.—D. p. 132.—Lam. 14.—Ch. f. 202, 3,4.—M. Susprricata. W. S. f. 6. Oblong, thin, dia- phanous, pale dull brownish-white, strongly plaited transversely - both inside and out ; hinge much nearer the anterior than the posterior extremity, both depressions flattened, the oblong posterior the most so. 13..23.—Indian Ocean. M. Rurescens. Lam. 15. Triangularly ovate, sub-equilateral, solid, rather tumid, reddish fulvous, slopes striated, smooth near the beaks which are approximate, but with coarse plait-like stricze to- wards the ventral margin, which is much arcuated but anteriorly incurved slightly ; inside opaque white, the teeth strong, the V- shaped one large, the lateral smooth, moderately distant, sub-equal. 1}..2.— New Holland. M. Macutata. Gm. 3260.—D. p. 134.—Lam. 16.—Ch. f. 208, 9.— E. t. 254. fi 3.—W. t. 6. f. 7. Obtusely triangular, slightly angulated at the anterior and rounded at the posterior depressed extremity, inflated, thin, white, with scattered reddish chesnut spots. 13..24.— Nicobar Isles. TRIBE MACTRACEA. 31 M. Suspuicata. Lam. 17.—Ch. f. 205, 6. Triangular, thin white, somewhat plaited at the sides near the beaks, dise smooth ; hinge with a lateral bilobed tooth.—A large species intermediate between Carinata and Striatella, having its anterior slope on each side bounded by an angle as in Plicataria. M. Trianeutaris. Lam. 18.—. t. 253. f. 3. Triangular, solid, white with transverse plaits and scattered chesnut spots which become larger as they approach the margin ; slopes grooved ; lateral teeth cross-ribbed and elongated.— The figure quoted by Lamare is nearly tnice as broad as it is long, depressed and marked with darker transverse bands on the depressions. 2..14. M. Lacrgea. Lam. 19.—An. Gmel. no. 11?—M. Sourpa. Payr. p. 30.—Poli. 1. t. 18.f. 13, 4. (magnified). —An.M. Corat- Lina. Lin.? Ovate-triangular, sub-equilateral, rather longer and slightly narrower posteriorly, very white, sub-turgid, thin, pellucid, delicately striated concentrically, the ventral edge much rounded. 2.— Mediterranean. Poli represents the depressions as very strong and apparently grooved. M. ApsreviaTA. Lam. 20. Obtusely triangular, transversely shortened, white with the depressions elegantly plaited. 12.—Port Jackson in New Holland. M. Ovauina. Lam. 21.—Deless. t.3. f. 7. Ovate, thin, pel- lucid, white, finely striated near the margin, anterior slope bounded by an angle; beaks very smooth. 12.—Jndian Ocean? M. Ausa. Lam. 22.—Ch. f. 220, 1?—H#. t. 254. fi 5? Obtusely triangular, turgid, diaphanous ; with minute transverse striee, anda few longitudinal obsolete lines. 2.—Indian Ocean. M. Sourpa. Lin. 1126.—D. p.140.—Lam. 23.— Don. t. 61. —Ch. f. 229, 0.—Mont. p. 92.—Turt. B. p. 67.—W. t. 6. f. 21.—Last. t. 253. f. 87. Sub-triangular, nearly equilateral, thick, opaque, slightly depressed from the beaks at both extremities, nearly smooth, witha few coarse concentric ridges, yellowish-white ; within glossy white and the lateral teeth striated. 13..13.—Hurope.! M. Sauaripa. Lam.26. Sub-triangular, tumid, ineequilateral, yellowish obscurely speckled with fulvous ; anterior side the longer, and stained with brown. 1,°,.—T'he shell I have figured agrees exactly with this brief description, but is, I fear, no more than a variety of Maculata. M. Brastni1ana. Lam. 27.—An. M. Fraciuis, Ch. f. 235.— An. D. p. 145. in part.— Turt. B. t. 4. f. 10. Ovate-elliptical, sub-equilateral, sub-triangular, nearly smooth ; anterior slope with obliquely diverging longitudinal striz, epidermis brown. 23.— Lio 1M. Castanea, Lam. 23, is a depressed and rubbed variety of this species, and M. Rufa, Lam. 24, is a rubbed Stultorum. oe TESTACEOUS MOLLUSCA. Janeiro.—-The Oblonga of Say, in Journ. A. N. 8. Phil. 2, and the Californica of Conrad, in the seventh vol. of the same work, are (to say the least) closely allied to this species.1 M. Petuucipa.* Chem. f. 234.—D. p. 144.—M. Depressa. Lam. 29.—M.Deausata. Mont..p. 95. t. 5. f. 1.—W. t. 6. f. 32. Sub-ovate, thin, pellucid, white and convex; disc smooth and depressed, the sides with somewhat plait-like strie.— Brazil. M. Lisor. °. C. Pranicostatum. Sow. Z. P. 1833.— Reeve. t. 77. f. 25.— C. I. f. 25. Subcordate, palish, variegated with brown and fulvous ; posteriorly rounded, anteriorly truncated and obtusely angulated, the centre of the anterior area rather prominent; with thirty flattened sharp-edged radiating ribs, of which the posterior ones are transversely costellated, the anterior ones anteriorly crenu- lated and all of them closely striated transversely ; the umbones prominent : a deep depression under the umbones is posteriorly conspicuous. C. America, 13..12.—Closely resembling Me- dium. C. DonacirorME. Schreter. Hin. 3. p. 68. t. 7. f. 14.— Brug. p. 214.—W. t. 5. f. 38. — Gimel. 3247.—D. p. 114.—Ch. f. 165.—C. I. f. 27. Subtriangular, thick, posteriorly rounded and attenuated; anteriorly very short, the slope flattened ; ventral edge strongly arcuated and subincurved anteriorly ; white, marbled with, and the anterior slope almost entirely, livid brown, with radiating grooves, which become obsolete at one end: inside white, the margin strongly dentated. 3..1.—Much resembling Donax Cardioides. C. Susretusum. Sow. Jun. Z. P. 1840.—C. I. f. 24.— Reeve. t. 86. f. 24.—White, obliquely subquadrangular, ventricose, anteriorly subcarinated and acuminated, posteriorly subrotund ; before the angle flattened and slightly grooved, behind the angle with six tuberculated ribs, interstices dotted: a heart-shaped eavity close under the umbones, a slight callus within it. CARDITA. Shell free, regular, equivalve, inequilateral ; hinge with two un- equal teeth ; primary tooth short, direct, placed under the umbo ; the other oblique, marginal, and produced under the corselet. * Subcordiform or oval. C. Sutcata. Lam. 1.—Philippi. p. 53. Cuama ANTIQUATA. Lin. 1138.—D. p. 215.— Poli. t. 23. f. 11 to 19.—Ch. f. 488, 9. Subcordate, anteriorly longer, white with brown and rufous mark- ings and the beaks white ; longitudinal ribs convex and transversely striated so as to give rise to numerous little tubercles. 1}.— Mediter- ranean. C. Asan. Brug. Dict. p.406.—Lam. 2.—Adans. Seneg. t. 16. <* 2.—CHama A. JD. p. 216. Somewhat heart-shaped, slightly produced anteriorly, rufous scarcely spotted with white, with from twenty-one to twenty-six angulated compressed radiating ribs, whose sides are angulated and backs crowded with rows of scale- oe TRIBE CARDIACEA. 145 like tubercules, the interstices much broader than the ribs, the lunule small and excavated.—Senegal. (Reeve. Ic. t. 6. f. 23. ood.) C.Tureipa. Lam. 3. Obliquely heart-shaped, broader than long, tumid, posterior side very short and obtuse, with from eighteen to twenty longitudinal sub-angulated crenulated ribs: anterior slope broad and the posterior depression sunken and rounded _heart- shaped. Variety, smaller with the anterior depression more elevated and the crenations of the ribs more numerous. 132..2.—Indian Ocean.} C. InrerMepiA. Lam.6. Obliquely heart-shaped, transverse, the posterior side very short; transparent, with separated rounded and crenulated ribs the posterior ones grooved at the sides.— New Holland. (Exactly resembles the fossil represented in Brocchi Conch. ¢. 12. f.15. Isit a recent shell at all?) C. Trapezia. Lam. 9.—CuHamaT. Lin. 1138.—D. p. 216.— E. t. 234. f. 7.—-Ch. f. 2005, 6.—W. t. 9. f. 8. Trapeziform, with about nineteen or twenty crenulated ribs and the margin plaited, rather tumid, reddish and transparent: paler within. +..+4. —Norway. Mediterranean ? C. Bicotor. Lam. 10.—Reeve. Ic. t. 6. f. 29 —CuHama AntI- quaTta. Lin.—H. t. 233. f. 2, 3.—Ch. f. 490, 1.— W. t. 92 f. 4. Obliquely heart-shaped, attenuated produced and subangulated ante- riorly, white spotted with rufous on the angular ribs which have their upper surface flattened and most of them smooth, but the posterior ones thickly crenulated, inside uniform whitish. Varzety, smaller, not produced but crenated also posteriorly. (Ch. f. 488, 9.) 12.—Africa. C. Depressa. Lam. 11. Oblique, oval, depressed, white somewhat ferruginous, with crowded and moderately convex ribs which become indistinct anteriorly. 12.—Looks like a fossil. C.Boreauis. Conr. Am. M. C.p. 39. t. 8. f. 1.—Beechey, Zool. t. 44. f. 1.—Gould. Mas. f.59. p. 94. Rounded, obliquely heart-shaped, thick, strong, inequilateral, beaks prominent and recurved ; with about twenty rounded radiating ribs which are broader than their rough interstices ; epidermis rusty brown ; lunule small, deep, rhomboidal ; margin strongly crenated ; inside white ; hinge with two teeth in each valve.-—N. America. C.Crassa Sow. in Beechey. Zool. p. 152. t.42. f. 4. Obovate, subquadrate, very turgid, thick, roughish, white with a brown cuticle ; posteriorly very short scarcely projecting beyond the umbones ; with fifteen or sixteen broad rounded radiating ridges, the interstices narrow ; decussated near the umbones which are in- volute : ligament in a deep depression of the dorsal edge ; inner margin irregularly undulated. 14.—Acapulco. “1C, Squamosa. Lam. 4. is alarge Trapezia.””— Desh. L 146 TESTACEOUS MOLLUSCA. C. Cuvierr. Brod. Z. P.1832.—Reeve. Ic.t. 5. f. 24. Sub- cordate, whitish, mottled with rufous ; with broad and very elevated radiating ribs which are flat above and armed with Se: nodo- sities: within white: epidermis brown. 2-1,..2-8;.—Central America. C.Tumipa. Brod, Z. P. 1832.—Reeve. Ic.t. 5.f. 26. Subtri- angular, tumid, with broad radiating somewhat depressed ribs, flesh colour or tawny variegated with purplish-chesnut and yellow spots ; the umbones recurved and subacuminated; the lunule de- pressed, and the epidermis brown. 21..2.— Central America. C. Varra, .Brod.Z. P. 1832.— Reeve. Tc.t. 5, f. 25. Subtri- angular, with depressed radiating ribs, violet-chesnut mottled by white spots: depressions excavated: beaks much recurved. 17. .1}. —Gallapagos. C. Tricotor. Sow. Z. P. 1832. Rhombic ovate, broader than long, with radiating ribs, whitish with brown bands, the anterior dorsal margin and the short posterior side, orange : anteriorly longer ; the ribs (particularly posteriorly ) subgranular. Doel cs ghee Central America.— Probably a variety of the nest. C. Laricosrata. Sow. Z. P. 1832. Ovate rhombic, turgid, broader than long, with radiating ribs, a rather tawny epidermis, and brown bands ; anterior dorsal margin rather elevated ; the ribs broad, especially the posterior, decussated by raised lines. 11, 6.. 2, 1. —Central America. C. Spurca. Sow. Z. P. 1832. Ovate-oblong, white under an olive epidermis, with prominent granular radiating ribs : anterior side angular towards the dorsal edge. -{5..1.—Peru. * * More or less oblong. C. Muricata. Son. Z. P. 1832. Oblong, whitish, with muricated radiating ribs which anteriorly are large and distant, posteriorly are smaller and closer, posterior side extremely short. 0,55 ..1, 1.—Paeific C. PHrenetica. Lam. 12.—Cuama Suporsicunata. Lin. 1188-(—D. p. ARE. t, 233. f.4:-—Ch., f, 502, 3.— We 1a J. 9. Oblong, compressed rounder and broader towards the margin, with longitudinal grooves decussated by transverse strive, reddish brown with the posterior side whitish and similarly coloured within; posterior margin crenulated. 3..2.—Red Sea. C. Crasstcosra. Lam. 13.—Adans. Sen. t. 15. f.8?’— #.t. 234. f. 7? Elongated, posteriorly contracted and sinuous, white with purple and chesnut lines or spots, the ten or twelve thick ribs armed with imbricated obtuse scales which become semi-erect towards the margin: inner margin simply waved. 21.—Senegal.1 1 JT have received specimens named by M. Deshayes, and brought from Senegal by M. Rang. Whether they are the Crassicosta of TRIBE CARDIACEA. 147 C. Rurrscens. Lam. 14.—List. t. 347. f. 185? Oblong, posteriorly contracted and sinuous, reddish fulvous with seventeen ribs armed with imbricated flattened scales ; margin waved. —Ge- neral appearance of last.)—Giulph of Nicoya. C. VariecaTa. Brug—Cuama CarycunatTa. D. p. 217.— List. t. 347. f. 184.—Ch. f. 500, 1.—W. ¢. 9. f. 10.—Caropita C. Lam. 15.—Sow. G.— Reeve. t. 89. f. 2. Oblong, anteriorly retuse, increasing in breadth towards the margin, white with brown crescent spots and twenty or twenty-one ribs of which the lateral ones are crenated, the central armed with arched imbricated depressed scales ; white within with the margin plaited by the ex- terior ribs. 2.—Atlantie Ocean.’ C. Noputosa. Lam. 17.—H. t. 234. f. 1.—Ch. f. 1999 to 2002 ?— Del. t. 11. f. 8. Oblong trapeziform, gibbous, reddish rufous with sixteen rounded ribs armed with nodose crenulations : margin entire. 1}.—New Holland.— Chinese Variety. Mottled with white and rufous. C. Carycunara. Brug. p. 408. (excluding his synonym of Adanson.)—C. Sinvata. Lam. 18.—Cuama Catycutata. Lin. 1138.—An. Gual. t. 90. F?~—Poli. 2. t. 23. f. 7, 8, 9. Oblong, whitish, posterior side with two sinuosities one deeper than the Lamarck, I know not, but as to their identity with the Squamosa of Mr. Sowerby (in Tank. Cat.) there can be no doubt. They are of an oblong shape with the ventral and dorsal edges almost parallel and little curved. The ribs are in number sixteen, armed with depressed scales, convex, and not broader than their interstices. The lunule is minute and the inside pure white. The exterior under a tawny epidermis is either dirty white or orange red. The state- ment of Lamarck, that the ribs are but ten or twelve and that it is contracted and sinuated posteriorly, would agree better with Mr. Sowerby’s Squamifera, which I will now describe. C. Squamirera. Sow. in Tank. Cat. Oblong, contracted and sinuated posteriorly, expanded anteriorly; uniform purplish red or yellow, about twelve convex ribs armed with strong erect scales, the three subanterior ribs infinitely the larger, interstices rather broad : lunule minute : uniform whitish within, the margin slightly waved. 2. °C. Supaspera, Lam. 16.—Del. t. 11. f. 9—C. Variecara. Brug. no. 6. Oblong, gibbous, whitish, with twenty-three rufous imbricated scaly ribs ; the scales arched semi-erect and subacute : margin crenated. 13.—As Deshayes declares that the Variegata of Brugiereis Lamarck’s C. Calyculata, and the latter author founds this species on the identical specimen which Brugicre has described, it is probable that this species may be only a variety of the last. L 2 148 TESTACEOUS MOLLUSCA. other, with eighteen imbricated and scaly ribs; within with a brown or violet spot anteriorly or covering the surface, the lateral tooth rather acute. 14.—Mediterranean ? C. Concamerata. Lam. 19.—Cuama C. Lin. 3304.—D. p. 219.—Ch. f. 506.—E.. t. 234. f. 6.—W. +t. 9. f. 15. Ovate oblong, whitish within and without, with longitudinal ribs which are trans- versely striated and somewhat crenated ; the inner margin con- tracted and appearing as if doubled over in the middle so as to form an opposite ovate chamber in each valve. 3§..1.—W. Indies. C. Avicutina. Lam. 20.—Del. t. 11. f. 10. Ovate oblong, with (in the largest specimens) orange spots on the ribs ; the longi- tudinal ribs armed with imbricated scales which become arched and semi-erect as they recede from the beaks ; inside white. _1.— New Holland.—(Very close to, and possibly a variety of, Lamarck’s Calyculata.) C. Cirrina. Lam.21. Oblong spatulate, citron yellow, the longitudinal ribs crowded with imbricated scales which are more erect towards the margin and at the posterior extremity ; white within. +.—New Holland.—(Probably a young Crassicosta. Desu.)! C. Sustavicata. Lam. 22. Oval oblong, with white and rufous zones and irregular rays, with very delicate transverse stricz and the margin quite entire. #.—(In shape and hinge resembling a Cypricardia.—Desu.) C. Corsutaris. Lam. 23. Oval, somewhat trapeziform, thin, smooth, posterior side very short; margin quite entire. $.—On Corallines. C. Lirnorpuacetita. Lam. 24,.—Del. t. 11. f. 11. Oblong, cylindraceous, thin, compressed towards the margin, anteriorly dilated and obtusely truncated, ventral and ligamental edges sub- parallel and straightish, whitish with the beaks fulvous, very delicately striated transversely: the angle oblique and obtuse. 3.—Hurope?— Having the aspect but not the hinge of Cypri- cardia Coralliophaga. C. Raprata. Sow. Z. P. 1832.—Reeve. Ic. t. 1. f. 5. Oblong, palish, variegated with fuscous spots and bands; the posterior side 17 have not seen this species, but from its description, it seems allied to, if not identical with, the C. Sauamosa. Sow. Tank. Cat. --An. EH. t. 234. f. 3. Oblong, variable in colour being white orange-red, &c., but never spotted, armed with sixteen scaly radiat- ing ribs; the scales semi-erect and much more crowded on the narrower and closer posterior ribs ; ventral edge but shghtly waved, not sinuated. 2..14.—Senegal.—See my note on Crassicosta of which species this is possibly a variety. TRIBE CARDIACEA. 149 short, the anterior elongated ; with a few broad radiating ribs, the posterior ones transversely decussated, the central anteriorly angu- lated, the anterior rounded, dorsal edge scaly. =9,..2+45.— West Colombia, and Panama. C. Arrinis. Sow. Z. P. 1832.— Reeve. Ic. t. 1. f. 6. Oblong, pale mottled with fuscous, posteriorly short, anteriorly elongated ; a few radiating broad ribs which posteriorly are somewhat indistinct, anteriorly prominent angular and rather scaly. +8, .. 12.— Central America.—TIs this distinct from Pectunculus? C. Pecruncutus. Brug. p. 412.—Reeve. Ic. t. 1. f.4.—CHama P. D.p. 220.--W. t. 9. f. 16.—Lis. t. 347. f. 185. Transversely elongated, oblong, rounded at both ends, posteriorly very short, anteriorly produced and rather dilated, ventral edge incurved sub- centrally : thick moderately convex, brownish, with from eighteen to twenty smooth convex radiating ribs: inside reddish. 2..14.— South America ? C. Incrassata. Sow. Tank.—W.S.t. 2. f. 3.—C. Rusr- cunpA, Menke Cat. Transversely oblong, subrhombic, the liga- mental edge being almost parallel to the scarcely curved ventral, posteriorly very short; white or orange flesh colour, with sixteen thickened, elevated, rounded, crenated ribs, the interstices narrow : uniform white within.? CYPRICARDIA. Free, equivalve, inequilateral, obliquely or transversely elongated ; primary teeth three, situated under the beaks, and one lateral tooth produced under the anterior depression. C. Guintaca. Lam. 1.—Cuama Ostonea. Lin. 1139. D. p. 219.—Ch. f. 504, 5.--E. t. 234. f. 2.—Bl. t. 65. bis. yaa | tit ta jf. 14.—Oblong, the anterior slope obliquely angulated and compressed towards its extremity, yellowish white, decussated by fine striz, apex rounded: white within. 22.— Guinea.—Has the look of a Modiola.3 C.Aneutata. Lam. 2.—Ch. f. 1993, 4.—Cuama Rostrata. W.S.t. 2. f. 2. Oblong, obliquely angulated anteriorly, trans- versely grooved and decussated by longitudinal striz, white and slightly gaping at the base of the anterior side which is obliquely 2 Probably the Venus Acuxerata of Gmelin, (Schret. Hin. t. 8. f. 13.—D. p. 198.—W. t. 8. f. 89.) belongs to this genus, being described as having two cardinal teeth in each valve. 3 C. Cattrornica of Conrad differs not in description from this species.—Add the C. Osptonea of Sowerby (not of Lin.) C. An- cotata of W.S., t. 2. f. 1. 150 TESTACEOUS MOLLUSCA. truncated and carinated with its slope more or less concave: teeth and anterior end often tinged with purple internally: anterior dorsal edge rather incurved.—-Variety. C. Rosrrara. Lam.3. With the anterior side produced attenuated and slightly beaked. 12.— New Holland. C. CoratitiopHaca. Lam. 4.— Bl. t. 76. f.3.—CHama C. Gmel. 3305.—D. p. 220.—W. t. 9. f. 17.—Ch. f. 1673, 4. Oblong, rounded at both extremities, cylindraceous, thin, white tipped with purple at the beaks, diaphonous, compressed anteriorly ; marked with decussated strize which at the margin are raised into low ridges. 2.—In Madrepores at St. Domingo. (Bears some resemblance to Mytilus Lithophagus.) HIATELLA. Equivalve, very inequilateral and transverse ; gaping at the ventral margin ; hinge with a small tooth in the right valve; and two oblique somewhat larger ones in the left valve; ligament external. H. Arcrica.* Lam.—Turt. Biv. t. 2. f. 12.—Soten Minv- tus. Lin. 1115.—W. t.3. f. 33.—D. p. 69.—Mont. t. 1. f. 4. —Ch. f. 51, 2.—Saxicava A. Phil. t.3.f-3. Oblong, produced and truncated anteriorly, white with transverse wrinkles, ligamental edge subincurved, anterior slope with two oblique ridges usually armed with spines.—Variety. Without the spines. (H. Os- tonca. Turt. Biv. t. 2. f. 13.) 3.—Atlantic and Mediter- ranean.+ ISOCARDIA. Equivalve, heart-shaped, ventricose ; beaks distant, divergent, and spirally turned to one side; hinge with two primary flattened tecth, one of them recurved and under the beak; an elongated lateral one under the ligament which is external and forked on one side. I. Cor.* Lam. 1.—Bl. t. 69. f. 2.—CHuama Cor. Lin. 1137.—D. p. 212.—Ch. f. 483.—H. t. 232. ff 1.—Don. 4. t. 134.—W. t. 9. f. 1. Heart-shaped, globose, smooth, fulvous ~ and the beaks clouded with white; epidermis reddish. 3..23.— Europe. I. MottK1ana. Lam. 3.—Cuama M. JD. p. 213.—Ch. f. 484, 5, 6, 7.—Z. t. 233. f. 1.—Carpita M. Brug. Dic. p. 404. Heart-shaped, subtriangular, inequilateral, yellowish white, ! Compare Mytixus Pracisus of Montagu. t. 4. fi 2.—-(W. ¢.-1207 1) TRIBE ARCACEA. 151 obliquely grooved, the valves carinated ; anterior side the shorter, smooth and depressed. An. Var.? Sow. G. f. 3.—Reeve. t. 78. f. 3. Ribs closer and as well as the umbonal ridge, more obtuse. 1.—China and the Indian Ocean. I. Semisutcata. Lam. 4. Heart-shaped, thin, semi-trans- parent, white, transversely striated; anterior side with ten longi- tudinal grooves.® TRIBE ARCACEA. Primary teeth small, numerous, and disposed in a line in each valve, which is either straight arched or broken, the teeth of one valve fitting into the intermediate spaces of the other valve. CUCULLEA. Equivalve, inequilateral, trapeziform, ventricose ; beaks distant, separated by the area of the ligament; anterior muscular impression elevated, its margin angulated, or with an eared produced border ; teeth of the hinge straight, very small, and set transversely, with from two to five small parallel ribs ; ligament external. C. Auricunirera. Lam. 1.—Sow. G.—Reeve. t. 81. f. 1, 2, 3.—Arca CucuLtuEa. Gmel. 3311.—W. t. 9. fP 16.—A. ConcamerRATA. D. p. 232.—E. t. 304.—Ch. f. 526, 7. Ob- liquely heart-shaped, rhombic, cinnamon colour, ventricose, decus- sated by strize of which the longitudinal ones are the stronger ; within whitish, stained anteriorly with reddish or pale violet brown, with a laminar appendage proceeding from under the beak; hinge with two large teeth at each extremity. 2}..3}.—WNicobar Isles. ARCA. Transverse, subequivalve, inequilateral ; beaks remote, separated by the area of the ligament ; hinge linear, straight, without ribs at the extremities ; teeth of the hinge numerous, arranged in a row, serrated, close set, alternately inserted into opposite valves ; ligament entirely external. 2 For this species Deshayes proposes the establishment of the genus CarpiLiA. Oval-oblong, longitudinal, heart-shaped, ven- tricose, the beaks large and prominent; hinge with a small car- dinal recurved tooth, a pit at the side and a spoon-shaped pro- jection for receiving an internal ligament: anterior muscular scar rounded and superficial, the posterior placed on a thin horizontal plate which projects from beneath the hinge. 152 TESTACEOUS MOLLUSCA. * Margin entire. A. Tortruvosa. Lin. 1140.—D. p. 225.—Lam. 1.—Ch. f. 524, 5.—E. t. 305. f. 1.—W. t. 9. f. 1. Parallelopiped, obliquely keeled one valve more so than the other, twisted and almost equally broad throughout, but rather narrower at the posterior end, dirty or reddish white, with radiating strize and the anterior triangular portion strongly wrinkled transversely ; beaks small and recurved. 1..3—Jndian Ocean. A. Semirorta. Lam. 2.—Fav. t. 51. f. C. I.—W. S. t. 2. f. 2. Rather twisted, oblong elliptic, dilated, striated, the valves obsoletely carinated and rounded at their extremities ; beaks recurved. 31.—Van Diemen’s Land. A. Nom* Lin. 1140.—D. p. 226.—Lam. 3.—Ch. f. 529.— Blo t.650 9 f. 2 Dont. 158.9 Fa 2s Ee th 208s fae t. 305. f. 2.—W. t. 9. f. 2. Oblong rhomboidal, with fifty or sixty radiating grooves, the beaks incurved and very remote; whitish with diagonal broad parallel chesnut stripes ; the broad flat space between the beaks with a few distant grooves radiating from each apex ; inside tinged with chesnut, the hinge with more than eighty teeth; the marginentire. 1..2.—Hurope. The Atlantic. A. Navicunaris. Brug. E. p. 99.—D. p. 227.—W. t. 9. J. 5.—Ch. f. 533.—E. +. 308. f. 3. Oblong rhomboidal, pale rufous with broad wavy chesnut diagonal stripes, with not more than thirty coarse radiating ribs which become broader at the sides, and fine intermediate striz: within brownish, crenulated on the sides of the margin and the hinge with not more than seventy teeth. 2..13.—St. Domingo. A. Terracona. Poli. t. 25. f. 12, 3—Lam. 4.—Z#. t. 308. J. 3.—Phil. p. 57. Oblong, with longitudinal riblike strize, trans- versely striated, anteriorly straight not emarginated and with an acute prominent keel, pale rufous never striped. 1.—/Mediterranean. A. Impricara.* Brug. HE. p. 98.—D. p. 226.—A. Um- BonaTa. Lam. 5.—A. Fusca. Don. 5. t. 158. f. 4.—W. t. ald. Ob, of...539.-— dist. 1. 264, f 20ne sae yo: Ovate, posteriorly rounded, anteriorly forming an oblique angle with the hinge margin very ventricose brownish white within and without, with imbricated crowded decussated acute striee: liga- mental area hollow: margin gaping and quite entire. 1.— Jamaica.— Senegal. A. Srnuara. Zam. 6. Oval, obtuse at each extremity, with decussated striae, obliquely angulated, ventral margin sinuated and gaping. 12.—New Holland.—(Akin to Helbingti and probably a variety.) A. Avetuana. Lam. 7. Small, ovate, tumid, ventricose, shortened, with decussated striz, beaks arcuated, anterior slope TRIBE ARCACEA. 153 heart-shaped, white spotted internally with brown. 4.—New Holland. A. Carpissa. Jam. 8.—Del.t. 11. f. 14. Nut-shaped and transversely heart-shaped, valves keeled on the back, beaks almost obsolete so as to cause the dorsal edge to seem quite flat; the ligamental area lozenge-shaped and flat; ventral margin convex and gaping. 32.—British Channel.—A small inequilateral shell of an extraordinary shape for this genus. Placed on the pointed extremity of its elongated side, it wears the semblance of Cardium Cardissa, but without any apparent beaks. A. Sutcata. Lam. 11. Ovate, very obtuse posteriorly, and obliquely truncated anteriorly, entire, gaping ; white clouded with reddish brown, with longitudinal grooves which are transversely striated and subcrenated. 14.—New Holland. A. Ovata. Gmel. 3307.—Lam. 12.—W. t. 9. f. 12.—A. Nivea. D. p. 230.—Ch. f. 538.—H. t. 309. f. 3. Ovate, somewhat sinuated, ventricose, but depressed in the middle and rather angulated at one end, with crowded narrow decussated ribs under a scaly and brown epidermis, margin gaping in the middle, no posterior depression. 13..23.— Red Sea.—Deshayes holds this to be the same as Helbingit.2 A. Barpara. Lin. 1140.—D. p. 229.—Lam. 13.—W. t. 9. f. 3.—Ch. f. 535.—Bl. t. 65. f. 1.—H. t. 309. f. 1. Trans- versely oblong, depressed, somewhat sinuated in the middle, reddish brown becoming paler centrally under a brown epidermis which forms shaggy bristles on the crowded raised longitudinal strize, (crossed by delicate transverse ones); margin nearly closed, the umbones depressed but the beaks not distant, and the area between them covered by a brown ligament which adheres to it by means of several grooves nearly parallel to the hinge.— Variety. 1 A. Ventricosa. Lam. 9. being but a variety of Nox must be suppressed.— Deshayes. A. Retusa. Lam. 10.—Ch. f. 432. Oval, ventricose, obtuse at each end, decussated by the strie, the longitudinal grooves sub- imbricated: ligamental area brown and glabrous.— The specimens in the French Museum, being old Naviculares and the figure of Chemnitz being universally assigned to Imbricata, it is probable that this species must be expunged from our future catalogues. 2 Of this species, Deshayes considers as a variety the A. TRa- pezINA. Lam. 18.— Del. t. 11. f. 13. Ovate, elongated, subtra- peziform, depressed, pellucid, longitudinally grooved and transversely striated, the umbones smooth, the anterior edge very oblique and incurved, ventral arcuated ; area between the beaks concave and rather narrow. 14.— Timor and South Scas. 154 TESTACEOUS MOLLUSCA. A Cyuinprica. W. 8S. t. 2. f.. 3. Transversely elongated, very inequilateral, margins subparallel, scarcely at all sinuated. 13..23.—Mediterranean.— West Indies. With age the length increases more on the anterior than the posterior side, and the hinge consequently is nearer the centre in the young than in older specimens. A. Fusca. Brug.—Lam. 14.—A. Bicotorata. W. t. 9. f. 11. A. Barpata. Var. B. Gimel. 3307.—D. p. 231.— List. t. 231. f. 65.-—Ch. f. 534.—E. t. 308. f. 5. Oblong, rounded at both ends though slightly angulated anteriorly, de- pressed, covered with a woolly brown epidermis, reddish chocolate with a white ray extending from the depressed and whitish um- bones a little way down the anterior slope, with numerous fine longitudinal granulated ribs and delicate transverse striz; the margin all but closed. 13.—West Indies.—Beside the crenu- lations of the hinge, finer ones line the posterior and anterior margins. A. Macexuanica. Gmel. 3311.—D. p. 229.—Lam. 15.— Ch. f. 539.—E. t. 309. f. 4.—W. t. 9. fi 9. Transversely oblong, curved, contracted in the middle of the margin, posterior side the shorter and narrower, white or slightly ferruginous under a dark brown somewhat bearded epidermis; decussated by striz, the umbones approximated and the margin gaping. 24 —Straits of Magellan. A. Lacrea.* Jin. 1141.—D. p. 236.—Lam. 17.—List. t. 235. f. 69.—Pen. 4. t. 58. f. 59.—W. t. 9. f. 24. Oblong, subequilateral, rounded posteriorly, angular anteriorly, white with a brown velvety epidermis and crowded longitudinal grooves, merely crossed by the wrinkles of growth ; area between the beaks very sunken ; white within. }..3.—Hurope. A. Pistacuta. Lam. 19. Ovate, grey, with decussated strize, the beaks approximated and the valves internally striated and dark brown. 2.—Z%imor and South Seas. Smaller but scarcely dif- Jering from A. Fusca. A. Pisouina. Lam. 20. Very small, obovate, ventricose, decussated by strize of which the longitudinal ones are the more prominent ; beaks approximated, pearly within. 4.—New Hol- land. Not unlike Lactea in shape. A. CancrenuariaA. Lam. 21. Oval, quadrangular, violet brown within and without, with longitudinal granular furrows and transverse striz; beaks approximated. %.—Closely resembling Lactea in shape but more inequilateral and has some affinity also to Pisolina. A. Cautirera. Lam. 22. Oval oblong, rounded at each extremity, violet brown, with longitudinal transversely striated _—_ = —— TRIBE ARCACEA. 155 grooves: extremities of the hinge gibbous and callous: beaks oblique, approximated and but little prominent. +. A. Inupina. Lam. 23. Oval, tumid, with decussated striz, scaly at the margin and anterior extremity: beaks approximated and oblique. +.—(Closely resembling Venerupis Irus. A. Lacerata. Lin. mus. Tessin. p. 116. no. 2. § t. 16. if aia —D. p. 229.—Lam. 38.—W. t. 9. f. 10.—Ch. f. 536, 7.—E. t. 309. 7. 2. Transversely subovate, depressed, very inequilateral, brown under a greenish epidermis, with longitudinal radiating striz, which are ragged and ciliated, granular and unequal, the elongated hair of the epidermis disposed on them at regular distances: margin subcrenated and closed, ligamental area so narrow that the beaks touch. 2.—ZJndia. A. Reticuuata. Gimel. 3311.—D. p. 237.—Lam. 39.—Ch. f. 540.—W. t. 9. f. 25. Ovate, rhomboidal, very inequilateral, somewhat compressed, white under a brown epidermis, with fine equal decussated strize ; umbones minute and approximated ; area between the beaks narrow, and finely grooved.—Jndia. A. Gaimarpiu. Payr. Cat. p.61.t.1. f. 36. to 39. Small, whitish, quadrilateral, and equilateral, heart-shaped, ventricose, covered with a fine net work of longitudinal and transverse strie; beaks large, approximated and recurved, and the area between them forming a narrow deep channel.— Corsica and Sicily. A.Grapvata. Brod. § Sow. Z. J. 4.—Beechey. Zool. t. 43. f. 1. Oblong, anteriorly angulated: with concentric ribs which are radiatingly imbricated, forming as it were steps down to the ventral margin. ;%,. .1.—Mexico. A. Pactrica.—Byssoarca P. Sow. Z. P. 1833. Oblong, pale variously streaked with brown ; with radiating ribs: contracted in the middle, and the ribs smaller : umbones far apart: posterior side the shorter, acuminated dorsally, the ribs for the most part larger, wrinkled, the ventral margin sloping: anterior side very large, anteriorly emarginated, an obtuse keel from the umbo to the ventral margin : ligamental area very large, the margins broad: the gape in the ventral margin large. 2-3,..4.—W. Columbia. A. Dirvaricara.—Byssoarca D. Sow. Z. P. 1833. Oblong, whitish, with transverse grooves, which are radiatingly decussated; posterior side subangulated dorsally, the anterior with a spinous keel from the umbo to the ventral margin, and divaricating striae, which are elegantly decussated; ligamental area narrow. 42. .1. —Pacific. A. Sorrpa.—Byssoarca 8. Sow. Z. P. 1833. Squarish- ovate, thick, solid, equilateral, with radiating strize, most minutely decussated; posterior side rounded, anterior obtusely angulated; dorsally and obsoletely carinated ; ligamental area elongated, the ligament rhomboid, central. 2. .32.—Peru. o 156 TESTACEOUS MOLLUSCA. A. Truncata.—Byssoarca T. Son. Z. P. 1833. Oblong, boat-shaped, brown, with radiating granular striz centrally and posteriorly, anteriorly with an obtuse keel from the umbo to the margin, and radiating ribs which as well as their interstices, are obtuse and wrinkled: posterior side very short, angulated above and rounded near the ventral edge, the anterior elongated and abruptly truncated: ligamental area elongated and broad, the ligament quadrangular and only attached near the posterior portion of the area. 11..23,.—Gallapagos. A. AttTrrRNAtTA.—Byssoarca A. Sow. in Z. P. 1833. Ob- long, subcylindraceous, pale brown with radiating striz and deep grooves at the extremities : posterior side very short, obtusely angu- lated dorsally, ventrally rounded; anterior, elongated, with two strong ribs from the umbo to the ventral margin, the anterior ribs strong and wrinkled; anterior marginal teeth alternating; liga- mental area narrow, posteriorly broader. 32. .12.—W. Colombia. A. Vrevata.—Byssoarca V. Sow. Z. P. 1833. Ovate, rather compressed, with radiating ribs, decussated; dorsal edge biangulated; epidermis brown, with acuminated scales: liga- mental area narrow. 1. .3;4.— Pacific. A. Ostiauata. Gray. in W.S. t. 2. f. 4. Ovate-subcunei- form, extremely short, attenuated and almost pointed posteriorly, rounded and expanded anteriorly, beaks close: white under a fus- cous scaly epidermis, with (apparently simple) close radiating rib- like strize, hinge margin slightly curving : an internal livid stain on each side. 1..12. A. Morasitis.—Byssoarca M. Sow. Z. P. 1833. Oblong, pale brown, with decussating striee : posterior side usually shorter sometimes nearly equal, angulated dorsally, rounded ventrally ; anterior side rather long, angulated dorsally, a keel from the umbo to the lower and anterior margin: anterior area, with larger de- cussated sulci. ,9,..159,.—W. Colombia. A. Lirpopomus.—Byssoarca L. Sow. Z. P. 1833. Elon- gated, wedge-shaped, subcylindrical, with elegant decussating strize, posterior side the shorter and obliquely truncated; anterior elongated, sloping, rounded acuminate ; ligamental area deep, the ligament posteriorly ending in an obtuse angle: epidermis den- ticulated, subfoliaceous at the posterior angle, conspicuous : teeth very numerous, very small and much interrupted. 1..33. A. Guaciatis. Gray. in Parry. Sup. Thin, oval-elliptical, rounded at the sides, regularly finely and transversely striated ; epidermis silky : umbones towards the joint incurved and nearly close, the intermediate space lanceolate, yentricose ; margin even, thin: teeth very small and indistinct in the middle. 3..$.— North Pole. TRIBE ARCACEA. ay * * Inner margin crenulated. A. Hetsinen. Lam. 24.—A. Canpipa. G mel. 3311.—D. p. 228.—Ch. f. 542.—W. t. 9. f. 7. Transverse, anteriorly pro- duced, posteriorly truncated, white under a scaly epidermis, with longitudinal crenulated grooves, which are in pairs at the anterior end: beaks approximated, margin gaping and somewhat crenu- lated. 2.—Guinea and Brazil.—“ Probably a variety of Ovata.” DeEsu. A. Scapna. Lam. 25.—Ch. f. 548. Transversely oblong, ventricose, thin, white with the umbones reddish and oblique ; with from twenty-nine to thirty-four ribs, which are divided into two portions by a groove, (which is narrow but almost as deep as the spaces between the ribs,) and are narrow and prominent parti- cularly on the anterior side. 5=India ?—W. Indies ? A. AntiquatTa. Lin. 1141.—D. p. 232.—Lam. 26.—W. t. 9. f. 17.—Ch. f. 548.—E. t. 306. f. 2.— Gual. t. 87. ¢. Trans- versely ovate, obliquely heart-shaped, thick, white, ventricose, with numerous flattened ribs, which are transversely striated, unarmed and the posterior ones bifid: anterior side slightly angulated: area between the beaks not grooved. 2..3.—Mauritius, Mada- gascar, 5c. A. Ruompera. Born.—Gmel. 3314.—D. 233.—Lam. 27,.— Ch. f.553.—E. t. 307. f.3.—W. t. 9. f.19. Heart-shaped, nearly as long as broad, gibbous, white covered by a brown epidermis, with about twenty-six longitudinal transversely striated ribs, and their interstices nearly smooth: beaks incurved and distant, the area between them rhomboidal. 14..13.—W. Indies.—H. Indies? A. Granosa. Lin. 1142.—D. p. 233.—Lam. 28.—W. t. 9. f. 18.— List. t. 241. f. 78.—Ch. f.557.— Knorr. 3. t. 4. f. 2.— Som. G.—Receve. t. 82. f. 3. Heart-shaped, nearly as long as broad, very ventricose, thick, almost equilateral, with upwards of twenty rounded ribs, armed with orbicular, somewhat spinous nodules, white within, and without, tinged slightly with brown at the beaks, which are incurved and rather distant with the area between them covered with a dark brown ligament, marked with rhomboidal grooves. 12. .2.—Jndian Ocean. A. Auricutata. Lam. 29.—Del. t. 11. fi 12.—Savig. Ligyp. t. 10. f. 8. Heart-shaped, ventricose, white, under a hairy epidermis, with about twenty-eight strong radiating crenulated 1 Deshayes separates as confounded with this, a species which I propose to name in honour of that laborious savant, A. Drs» HAYESII.—Grual, t.87. B.— LH. t. 306. f. 1. Oblong, rather thin, with rounded ribs and the area between the beaks marked with lozenge-shaped grooves. 158 TESTACEOUS MOLLUSCA. ribs, which are much narrower than the interstices, umbones oblique; posteriorly, obliquely rounded ventrally, rectangular dor- sally; emarginated anteriorly: ligamental area narrow and elon- gated anteriorly. 13.—Indian Ocean.— Much resembles Rhombea. A. Ineaurvatyvis. Brug. dict. no. 16.—A. Inpica. var. D. p. 235.—Ch. f. 552.—H. t. 305. f. 3. a.—A. ImBricata. W.t.9.f.4. Obliquely heart-shaped, ventricose, inequivalve, one valve projecting beyond the other anteriorly, and at the rounded ventral margin; rather broader than long, anterior edge nearly direct, white, thin, with many nearly smooth and flattened ribs, beaks approximate. 22.—IJndian Ocean. A. Invica. Gimel. 3312.—D. p. 234.—Lam. 31.—W. t. 9. f. 21.—List. t. 232. f. 66.—Ch. f. 543. Transversely elongated ovate, inequivalve, thin, and whitish s with many ribs which are grooved in the middle, the beaks approximated and no area between them. 1..13.— Sumatra. A. Seniuis. Lin. 1142.—D. p. 234.—Lam. 32.—Ch. f. 554. 5, 6.—. t. 308. f. 1.—W. t. 9. f. 20. Obliquely heart-shaped, nearly as long as broad, tumid, thick, ponderous, white covered with a greenish brown epidermis, with about twelve broad very large unarmed ribs, of which seven or eight are much larger than the rest ; umbones large, obliquely recurved, and distant: within white and polished.— Diam. 23}.—Africa. A. Brasiuiana. Lam. 33.—W. S.t. 2. f. 7.—A. INEQUIVAL- vis. Sow. Gen. f. 3. Inequivalve, heart-shaped, tumid, anteriorly subangulated, reddish white, with many flattened ribs which at the posterior side are crenulated, at the anterior unarmed: ligamental area pectinated. 12.— Rio Janeiro. A. CorsicuLa. Gmel. 3310.—A. CorsuLa. D. p. 235.— Lam. 34.—Ch. f. 559.—E. t. 309. f. 5. Ovate, subtrapeziform, the hinge margin nearly straight, and the rest of the margin rounded, white with radiating transversely striated ribs: beaks obtuse and approximated, the intervening area very narrow. 4..1. Cape of Good Hope. A. Sqauamosa. Lam. 35.—An. Gray. in W. S. t. 2. f. 12?} Ovate wedge-shaped, with cancellated striz, beaks tumid and approximated, anterior slope oblique, and imbricated with scales. 2. —-New Holland.2 1 The shell from which this figure is taken, is again named by Mr. Gray in the British Museum A. Reticulata var. Are we to understood that these are synonymous ? 2 Of this species, A. Domincensis, Lam. 16. is at most a variety (fide Deshayes). I add however the characters.—A. Domincensis. Lam. 16.—List. t. 233. f. 67. Transversely oblong, with decussated striz, reddish brown clouded with pale TRIBE ARCACEA. 159 A. Cavennensis. Lam. 36. Obliquely oval, pectiniform, red- dish yellow, with at least thirty radiating unarmed ribs, which are angular but flattened on the surface; anterior side broad and obliquely rounded, furrows Visible within.— Variety. Smaller, obliquely heart-shaped, and the ribs slightly crenated. 14.— Guiana. A. Bisutcata. Lam. 37. Transversely oblong, anteriorly an- eulated, longitudinally grooved, the ribs transversely striated and alternately smaller, yellowish or reddish white: inner margin obscurely crenulated.—Variety. With crenulated ribs. 14.— Guiana § Brazil. A. Inconerva. Say. Jour. A. N. 8S. Phil. 2. p. 268. Somewhat rhomboidal with from twenty-six to twenty-eight close set ribs crossed by elevated obtuse equal and equidistant lines except on ten ribs of the disc of the left valve; apices opposite the middle of the hinge, distant with a narrow lanceolate area between them: dorsal edge angulated at each end, posterior edge rounded, ventral edge rounded, that of the right valve extending a little beyond the regular curve in the middle : anterior margin cordate, anterior edge nearly straight. 2..21.—U. States. Very like Rhombea, but the figure in the Encyclopedie differs. A.Ponperosa. Say. Jour. A. N. 8. Phil. 2. p.267. Some- what oblique, very thick and ponderous, with from twenty-five to twenty-eight ribs, each marked by an impressed line and as wide as the interstices ; umbones, very prominent, apices remote and op- posite the middle of the hinge; ligamental area with longitudinal lines as prominent as their corresponding teeth ; anterior margin cordate, flattened, distinguished from the dise by an abrupt angular ridge, posterior edge rounded very short, ventral nearly straight or in- curved in the middle. 22..23.—U. States. A. Lasiosa. Sow. Z. P. 1833. Inequivalve, short, of a rounded square shape; posteriorly shorter, angulated dorsally and rounded ventrally, anteriorly subangulated ; whitish under a thin brown epidermis, with radiating ribs which (especially on the larger valve) are posteriorly granular, anteriorly smooth : ligamental area narrow. 1,3,..1%.—Peru. A. Pexata. Say. Jour. A. N. S. Phil. 2. p. 268.—-Gould. Mas. p. 95. f.60.—A. Americana, W. 8. 4.2. f.1. Trans- versely ovate subquadrate, very inequilateral, heavy, with from thirty-two to thirty-six close set ribs, which are broader than their interstices ; a shaggy brown epidermis ; beaks prominent and very oblique, apices approximated : posteriorly obtuse and (save when young) destitute of a dorsal angle; anteriorly obtuse, with an angle fulvous; anterior side produced, subacute and granular; beaks approximated, margin indistinctly crenated. 13.—St. Domingo. 160 TESTACEOUS MOLLUSCA. at the termination of the hinge, ventral edge little rounded. 1,1,..2.—U. States. A. Concinna. Sow. Z. P. 1839. Oblong, inequivalve, white, with radiating ribs which posteriorly are wrinkled, the interstices decussated ; posterior side the shorter and angulated dorsally, an- terior rather produced, the angle inconspicuous: ligamental area narrow and posteriorly crenulated on each side: ligament anterior : an olive epidermis which is spinous at the grooves on both ex- tremities. 13..1,3,.—Central America. A. Osesa. Son. Z. P. 1833. Ovate, posteriorly shorter, anteriorly subangulated, ventricose, white under a brown scaly epidermis, with crowded smooth flattened radiating ribs : hinge area shortishand narrow. 1;1,..113.—W. Colombia. A. Lasrata. Sow. Z. P. 1833. Inequivalve, short, of a rounded square shape, posteriorly shorter and rounded, anteriorly subangu- lated ; white under a brown epidermis which is setose on the anterior edge of the flattened radiating ribs ; these are (particularly on the larger valve) posteriorly wrinkled, anteriorly smooth and broader : ligamental area broad, subrhomboid. 1 -1,..14.—fteal Llegos. A. Nux. Sow. Z. P. 1833. Oblique, turgid, inequivalve, with radiating ribs which armed with granules in one valve are only so posteriorly in the other; umbones distant, prominent : epidermis brown, horny, thin, and the anterior side of the ribs bristly. 13, .15.—Aipinapr. A. Braneutata. Sow. Z. P.1833. Oblong, posteriorly shorter and broader, anteriorly subacuminated, lateral margin sloping 3 ven- tricose, with radiating ribs, white under a bristly brown epidermis: dorsal margin posteriorly acute, anteriorly obtusely angulated : ligamental area elongated, posteriorly broader, flat. 13,..2.— W. Columbia. A. Formosa. Sow. Z. P. 1833. Oblong, subcylindrical, whitish, with radiating ribs which are numerous flattened and posteriorly double ; each hinge margin angulated ; posterior side the shorter ; hinge area broadish and elongated, epidermis in long pointed scales in the interstices, in bristly hairs anteriorly. 2,3,..44. —C. America. A. QuapritaTERA. Sow. Z. P. 1833. Quadrangular, with the sides angulated dorsally, the posterior dorsally rounded, the anterior obtusely angulated ventrally : ventricose, whitish under an . wolive epidermis, with radiating rounded ribs : ligamental area narrow. }%..1.—eal Llegos. A. Granpis. Sow. § Brod. Z. J. Obliquely subquadrangular, thick, white, with radiating rounded ribs, which are only crenu- lated at the posterior end, elsewhere unarmed ; epidermis smooth coriaceous. 34. .453,.—Like Senilis but longer and with more ribs. TRIBE ARCACEA. 161 A. Emarernata. Sow. Z. P. 1833. Oblong, subcylindrical, inequivalve, white, with radiating ribs : posteriorly short with the ribs narrower, and wrinkled; anteriorly elongated, with the ribs broader and smooth: anterior dorsal margin emarginated, liga- mental area narrow ; epidermis brown and bristly in the grooves. 4..13.—C. America. A. Tusercutosa. Sow. Z. P. 1833. Oval, turgid, oblique, subauriculated, with numerous radiating ribs armed especially pos- teriorly with scattered tubercles : umbones close, ligamental area narrow: anterior side the longer. 27'5..24.—/S. America. A. Carpirormis. Sow. Z. P. 1833. Inequivalve, suboval, rounded posteriorly, on the anterior side ventrally angulated : ven- tricose, whitish with radiating ribs which are smooth except on the posterior side where they are wrinkled, the interstices on the larger valve very narrow: lateral edge sloping : ligamental area small and subequal. 1,5 ..2.—California.—Aspect of the common Cockle. A. Murticostata. Sow. Z. P. 1833. Ovate-rhombic, pos- terior side angulated dorsally, and rounded ventrally ; anterior side angulated dorsally, lateral edge sloping ; a rounded keel running from the umbo to the base of the anterior margin : white under a brown almost satin-like epidermis, with numerous radiating mi- nutely decussated rounded ribs, which posteriorly are subgranular : the grooves rounded, the ligamental area broadish. 22..24,.— C. America. A. Noposa. Wood. S. t. 2. f. 8. Equilateral, tumid, ob- liquely subrhombic, white; hinge margin angulated at both ends, very obliquely so anteriorly ; rayed with about twenty-six flat ribs which angulated at their sides are rather broader than the simple interstices, and are decussated, except on the anterior slope, with transverse straight raised lines: ventral edge arcuated : ligamental arearhombic broad and short. 2.—S. America ? A. Transversa. Say. Journ. A. N.S. Phil. 2. p. 269.— Gould. Mas. p. 97. Oblong, rhomboidal, with from thirty-two to thirty-five ribs as wide as their interstices, apices separated by along narrow area (on which one or two angulated lines diverge from the apex) and situated at one-third the distance from the posterior end of the hinge margin which is angulated at each end ; of the anterior edge the superior half rectilinear, posterior edge rounded, ventral edge nearly straight. 13..11.—U. States.1 ‘See also the Compnanara of Ch. f. 544, 5. (D. p. 228.— W. t. 9. f. 8.) and his Plicata f. 2008 (D. p. 227. and f.—W. £. 9. fs 6.) M 162 TESTACEOUS MOLLUSCA. PECTUNCULUS. Orbicular, doubly convex, equivalve, subequilateral, and close ; hinge arcuated, teeth numerous, oblique, serrated, alternately inserted into the opposite valves, middle ones obsolete ; ligament external. * Surface not ribbed. Pitosus.* Lam. 2.—Philip. p.61.—Arca P. Lin.—W. t. 9. f. 37.—P. Guycimeris. Unpatus J Prnosus. Turton. Biv. t.12. f.1, 2,3,4.—P. Marmoratus. Lam.4.—ArcaP. D.p. 242.—W. t. 9. f. 36.—Arca M. Gmel. 3314.—Ch. f. 560. § 563.—List. t. 247. f. 82.—Knorr. 6. t. 14. f. 4.—Gualdt. t. 72. G.—E. t. 310. f. 3. Orbicular-ovate, becoming inequilateral by age, white with angular red streaks arranged either longitudinally or transversely (sometimes flesh colour with white spots and an- gular red ones) minutely decussated, the apices obliquely incurved, approximate : inside white or whitish : epidermis velvety. 13.— Atlantic and Mediterranean.’ P. Sicuuus. Reeve. Ic. f.41.—P. Gurycimerts. Sam. 1.— Philip. p. 60.—P. Pitosus. Sow. G'.—Reeve. Sys. t. 83. f. 1.— Ch. f. 564.—Poli. t. 25. f.17, 8 ?—List. t. 247. f. 82? Orbicular, rather broader than long, all but equilateral, rather depressed (except when aged) uniform, brownish red (usually with darker zones and the beaks often tipped with white) radiated by minute strie and delicate pale rather distant lines having the appearance of obsolete sulci : epidermis silky, brown. 3.—Medi- terranean. P. Unpuxuatus. Lam. 3.—Del. t. 12. f. 1.—Arca Unpata ? Lin.— Brug. Dic.p. 114? Ovate orbicular, tumid, inequilateral, anteriorly angulated and the longitudinal furrows very apparent : white with small waved rufous spots disposed in transverse rows : beaks with a straight inclination to each other. 13.—America? P. Scriprus. Lam. 5.—Reeve. Ic. f.6 ?%—Arca Scripta. D. p. 243.—Born. t. 6. f. 1. a.—List. t. 246. f. 80.—E. t. 311. f.8.—W.t.9. f. 39. Orbicular, rather depressed, with minute de- cussated striee, whitish with angular fulvous lines ; beaks slightly curved anteriorly : within white stained with yellow at the anterior end, crenations of the margin about fifty and only visible in the centre. 14.—S8t. Domingo. 1 From an examination of Linneus’s own specimen, I can safely assert that M. Deshayes is in error in considering this shell to be the Gilycimeris of Linneus. The specimens of the latter are the Violascens of Lamarck. TRIBE ARCACEA. 163 P. Pennacevus. Lam. 6.—Reeve Ic. f. 24. (good)— Knorr. 5. t. 30. f. 3.—Arca Decussatra. Lin. 1142?—D. p. 239? —W.t. 9. f. 31. Orbicular, swollen, decussately striated, longi- tudinal striz the stronger, whitish irregularly painted with large and small dark brown spots: umbones bent inwards to the posterior end of the ligament: lunule heart-shaped, with transverse red rays. 2.—West Indies. , P. Rupens. Lam. 7.—E£. t. 310. f. 3.—Reeve. Ic. f. 23? Orbicular, convex, decussated by very delicate strize, pale reddish with many zones and numerous small darker spots: ligamental area narrow: one large internal brown stain. 23.—M. Deshayes states that the figure quoted by Lamarck represents Glycimeris. P. Ancutatus. Lam. 8.—Reeve. Ic. f. 30.—Arca_ A. Gmel.—D. p. 2407—W. t. 9. f. 34.—Ch. f. 567.—List. t. 245. f. 76?—Brug. no. 28. Subcordate, ventricose anteriorly angulated, longitudinally sulcated and striated rich chesnut (some- times with white splotches): ligamental area rather short. 1}$.— America. P. Sretuatus. Lam. 9.—Reeve. Ic. f. 5.—Arca 8S. Brug. no. 32.—D. p. 242.—Bon. t. 2. f. 62. Orbicular-heart-shaped, yellowish violet, umbones peculiarly starred with white, ornamented with very faint rather remote longitudinal striae. 2.—Portugal. P. Pautens. Lam. 10.—Arca P. Lin. 1142.—D. p. 246. —W. ¢t. 9. f. 33. Lenticular, inequilateral, with decussated striz, of which the longitudinal are the more prominent, white clouded or spotted with very pale violet; beaks approximated and not in- clining. 13.—Indian Ocean.—Variety. With more colour, beaks not so approximated and rather oblique.— Gulf of Taren- tum. ‘* Probably only a young Violascens.” Drsu. P. Gurycimeris. (not Lam.) ArcaG. of Linnzus (fide his own specimens.) P. Vioxascens. Lam. 11.—Payr. t. 2. f. 1. —Reeve. Ic. f.9.—Del. t. 12. f. 2. Heart-shaped orbicular oblique (becoming tumid by age,) greyish or reddish violet with paler radiating lines having the appearance of sulci or obsolete ribs, and concentrically striated on the umbones: beaks directly incurved and situated nearly in the centre of the ligamental area: anterior side elongated and angulated by age: within, more or less stained with brown anteriorly. 13..2.—WMediterranean.—Young. P. Nummarius. Lam. 14.—Arca N. Lin. (certo.)—D. p. 243. Densely variegated with liver colour on a white ground, with prominent concentric strize.! 1 Mr. Reeve assures me (having examined Lamarck’s own specimen,) that the Zonalis is but a variety of this species. M 2 164 TESTACEOUS MOLLUSCA. P. Srriarunaris. Lam. 13.—Reeve. Ic. f. 271 Ovate heart-shaped, transverse, reddish white under a brown silky epi- dermis, with very numerous fine longitudinal strie ; beaks rather oblique ; within white with a large stain of reddish brown. 14.— New Holland. P. InrermMepivs. Brod. Z. P. 1832.—Reeve. Ic. f. 1. Suborbicular, subglabrous, subdepressed, whitish, with pale chesnut radiating zones near the umbo, with rather distant radiating decussated strive: inside white, the margins crenated: epidermis somewhat velvety. 1;%..13.—JIquiqui. P. Ovatus. Brod. Z. P. 1832.—Reeve. Ic. f. 2. Exactly oval, longer than broad, convex, glabrous with very minute trans- verse lines, whitish, the umbones pale chesnut: inside white, the margin crenulated; the epidermis somewhat downy. 13..14.— Pacific. Closely resembling the last, but much more elongated. P. Lineatus. Reeve. Z. P. 1843.—Reeve. Ic. f. 25. Orbi- cular convex, slightly auriculated, decussately striated, longitudinal strie the stronger, whitish clouded anteriorly and about the middle with chesnut spots and vividly painted posteriorly with dark lon- gitudinal lines: umbones central. 13.—West Indies. Closely allied to Pennaceus. P. Macuratus. Brod. Z. P. 1832.—Reeve. Ic. f. 4. Orbi- cular, slightly eared, subequilateral, convex, whitish spotted with chesnut, somewhat decussated with thick set radiating strize: in- terior white, margin crenated: epidermis brown and downy. 23..23.—Central America. | P. Gicantevs. feeve. Ic. f. 3. Orbicular, very convex, (depressed when young) solid, large, with longitudinal close and regular strize and almost obsolete grooves; white stained with chesnut towards the ventral edge, middle and umbonal portion profusely and vividly painted with waved reddish brown spots touching each other for the most part on both sides: interior white, margins of the adult of bright shining chesnut, crenated : epidermis thick and hairy. 4.—California. Allied to the Un- datus of Linneus. P. Muutisrriatus. Desh.— Reeve. Ic. f. 42—Arca M. D. p. 224.—A. Srriata. Gimel. 3308.—W. t. 9. f. 41:—Ch. f. 537.—#. t. 311. f. 7? Triangularly orbicular equivalve, sub- equilateral, compressed, with numerous fine longitudinal strize rufous; beaks incurved and the area between them narrow; within brown, the margin flattened and quite entire. 1.—ed Sea. Haxtremely delicate transverse strie at intervals. * * With prominent radiating longitudinal ribs, either mith or nithout transverse strie. P. Castaneus. Lam. 15.—W. t. 9.—Reeve. Ic. f. 32. TRIBE ARCACEA. 165 Arca EaquitaTeRA. Gmel.—D. p. 240.—Ch. f. 562.—E. t. ll. f. 2—W. t. 9. f. 32. Orbicular, subequilateral, chesnut, mottled with white, with numerous longitudinally striated ribs, which become obsolete towards the beaks which are not inclined ; within white. 13.—W. Indies. P. Pectinirormis. Lam. 16.—Reeve. Ic. f. 11.—Arca Pectuncutus. Lin. 1142.—D. p. 238.—W. t. 9. f. 29.—Ch. J. 568.—E. t. 311. f. 5. Suborbicular, thick, moderately convex, somewhat eared, whitish more or less tinged with flesh colour, and marked with brown wavy riband-like stripes, or spots, the ribs and interstices both broad and the surface roughened by fine raised transverse wrinkles ; beaks small and not inclining: within white stained with chesnut at the hinge and near the beaks, the margin plaited. 14.—Asiatic and American Seas. A slight incurvation of the anterior margin. P. Pectinatus. Lam. 17.—WReeve. Ic. f. 28.—Arca P. Gmel. 3313.—D. p. 239.—Ch. f. 570, 1.—#. t. 311. f. 6.— W.t. 9. f. 30. Lenticular, rather depressed, whitish with wavy brown transverse markings or small spots, and numerous smooth rather flattened ribs and narrow interstices : white within and the margin crenated. 3.—W. Indies.—Variety from Brazil. White mith rufous spots. P. Rapians. Lam.18. Suborbicular, transverse, inequilateral, rufous the umbones very white, with very numerous fine, longitudinally striated ribs.—Variety. With the ribs broader, 11.—New Holland. P. Virreus. Lam. 19. Orbicular depressed, somewhat eared, thin, pellucid, with transversely striated almost granular longitu- dinal ribs, white with a few orange dots; beaks small and acute : the hinge formed of two straight lines which almost form a right angle at the beaks. and are each furnished with from twelve to fifteen oblique teeth. 12.—South Seas. P. Mututicosratus. Sow. Z. P. 1832.—Reeve. Ic. f. 26. Suborbicular, white mottled with chesnut, rust-colour, and ashy- grey; with numerous radiating small rounded ribs which are transversely striated : umbones posteriorly inflected. 143.—South America. P. Parcieictus. Reeve. Z. P. 1843.—Reeve. Ic. f. 14, Rather. obliquely heart-shaped, radiately ribbed; ribs. flat, often grooved up the middle, interstices deep ; white sparingly variegated with yellowish chesnut undulated zones. and patches: interior white with a purple-posterior stain. 1.—‘* The ribs are peculiarly JSirm and squarely grooved out.” P. Aurirtuus. Reeve. Z P. 1843.—Reeve. Ic. f. 17. Orbicularly heart-shaped, inequilateral radiately ribbed, ribs broad 166 TESTACEOUS MOLLUSCA. and obsoletely grooved down the middle ; white richly painted with transversely flowing patches of bright orange, which on the pos- terior half of the shell are edged with blackish brown. 2.— Philippines. P. TresseLttatus. Son. Z. P. 1832.—Reeve. Ic. f. 29. Orbicular, triangularly attenuated towards the umbones, equilateral, solid, tumid, white tessellated and variegated with brownish or purplish lake; the radiating ribs depressed and rounded, smooth, equal in size to the interstices, about twenty-five in number: beaks inflexed ligamental area small. 2.—W. Colombia. P. Morum. Reeve. Z. P. 1843.—Reeve. Ic. f. 40. Some- what pecten-shaped, pale pink sparingly and irregularly painted with long ruddy spots: radiately ribbed, ribs smooth: umbones nearly central. %.—Madagascar? Allied to the last. P. Ocuuatatus. Reeve. Z P. 1843.—Reeve. Ic. f. 38. Somewhat pecten-shaped, radiately ribbed, brown sparingly and irregularly ornamented with white spots or spaces bordered with dark brown: umbones central but rather oblique. 2.— West Indies. P. Nopvosus. Reeve. Z. P. 1843.—Reeve. Ic. f. 22. Sub- orbicular, longer than broad, yellow variegated with dusky brown or chesnut, radiately ribbed, ribs distant and knobbed, the knobs nearly obsolete posteriorly: interior whitish, brown posteriorly. 1..14.— Ceylon. P. Pauurum. Reeve. Z. P. 1843.— Reeve. Ic. f. 21. Ob- liquely ovate, subtriangular, the shell being much contracted to- wards the umbones: rich brownish yellow vividly painted with scattered square dark spots: radiately ribbed, ribs nearly obsolete towards the margin. §..14.—Zanzibar. P. Brcotor. Reeve. Z P. 1843.—Reeve. Ic. f. 20.— Beechey. Zool. t. 42. f. 3. Suborbicular, inequilateral, broader than long, attenuated towards the umbones longitudinally grooved, grooves numerous and very narrow, whitish clouded with violet and irregularly painted with triangular rusty reddish spots. 2.,1. — California. P. Srrieitatus. Son. Z P. 1832.— Reeve. Ic. f. 31. Suborbicular, triangularly attenuated towards the umbones, ven- tricose, pinkish variegated and streaked with rust-colour; the radiating ribs rather distant and rounded, interstices smooth. 1..1.—South America. P. Inazauatis. Son. Z P. 1832,.—(not Beechey. Zool.)\— Reeve. Ic. f.16.—P. Pecrintrormis. W.S.t. 2. f. 11. Sub- cordate, oblique, inequilateral, longer than broad, gibbous, with obtuse radiating striee white or lilac-grey with four or five broad, rusty or blackish transverse bands, the strize disposed in rib-like clusters and their interstices striated. 13..13.—Panama. The TRIBE ARCACEA. 167 ligament is short and a very small part is posterior to the umbones.4 NUCULA. Transverse, oval-trigonal, or oblong, equivalve, and equilateral ; no ligamental area ; teeth of the hinge linear, numerous, and pectinated, interrupted in the middle by an oblique produced hollom ; beaks contiguous, posteriorly inflected ; ligament mar- ginal and partly internal, inserted in the cardinal hollow. * Lanceolate. N. Lanceouata. Lam. 1.—Sow. G. f. 1.—Conch. II. Nucula. f. 1.— Reeve. t. 84. f. 1. Extremely long, thin, fragile, hyaline, anterior side lanceolate and rather obtuse, the posterior equally long but obtuse and broader, ventral margin entire.— A ipivapt. N. Evoneata. Son. Z. P. 1832.—Con. Il. f. 2.—Reeve. t. 84. f. 2. Transversely elongated, lanceolate, thin white with a fuscous epidermis towards the ventral margin: subequilateral but rather shorter posteriorly : dorsal margin rather straight, anteriorly subreflected : anterior row of teeth divaricate. =%..2,7,.—West Colombia. N. Tevurnoipes. Sow. G. f. 2—Arca T. W. S. t. 2. f. 3. Lanceolate, transversely elongated, subequilateral, anteriorly subangulated, posteriorly rounded, sides nearly equal in depth; white, thin, the lines of growth decussated by very fine oblique striee, dorsal edges convex. #..2.—Cuwmana. N. Paraconica. D’Orbigny. Lanceolate, very narrow, de- pressed, rather fragile, equilateral, rounded posteriorly, extremely attenuated anteriorly, with very fine concentric strize ; ventral edge entire, little arcuated in the centre, and sloping, obliquely at each end; dorsal edges little sloping the anterior one incurved and excavated above; teeth very numerous, cardinal pit broadly tri- angular. }..13.—Patagonia. N. Crenirera. Sow. Z. P. 1832.—Reeve. t. 84. f. 3.— Con. Il. f. 3. Transversely elongated, lanceolate, smooth, with 1 The P. Assimiiis of Sow. in Z. P. 1832. is most closely allied (if indeed distinct from) this species. See too Spurcus, Cancellatus and Pertusus of Reeve in the Zoological Proceedings, which should be compared with the young of the other species. His Flammeus though certainly distinct is only described from worn specimens. So too is the P. Longior of Sowerby. {68 TESTACEOUS MOLLUSCA. very fine transverse striz, the dorsal margin carinated, the keel crenulated. 4..12.—Xitpixapi. * * Postrated. N. Arctics. Brod. Z. J. 4. t. 9. f. 1. Oblong, anteriorly subrostrated, the beak slightly recurved posteriorly longer and somewhat rounded; epidermis thick shining and dark olivaceous; the delicate lines of growth crossed centrally and anteriorly by strong oblique strie. 7,..13.—Kamskatchka. The edge of the anterior slope forms a sharp elevated ridge when the valves are closed.1 N. Nrcoparica. Lam. 4.—C. I. f. 4.—Reeve. t. 85. f. 4.— Arca Prexvuucipa. Gimel. 3308.—W. t. 9. f. 26.—A. Levi- Gata. D. p. 237.—Ch. f. 541.—E. t. 309. f. 8. Transverse, ovate-elliptic, or ovate oblong, anteriorly subangulated, thin, smooth yellowish, pellucid, obtuse at the extremities but anteriorly rather attenuated: margin entire. 1— Indian Ocean. N. Rosrrata. Turt. B. p. 178.—Arca R. Mont. Sup. t. 27. f. 7.—D. (in part.) p. 245. Oblong, thin, pellucid, white, smooth, rather gibbous ; posterior side rounded ; anterior acumi- nated, turned upward, with three crenated ridges; surface covered with oblique nearly longitudinal grooves, margin entire. 2.. '5.— Guinea, Sc. N. Petra. Lam. 3.—Sow. G. f. 4.—C. I. f. 6.—Reeve. t. 85. f. 6.—Arca P. Lin. 1141?—D. p, 237 ?—Ch. f. 546 ?— W.t. 9. f. 27.—N. Srriata? Philippi. p. 64. Transversely ovate subtriangular, subequilateral, yellowish olive, thin, pellucid, with regular transverse grooves: posteriorly rounded, anterior dorsal edge but little if at all incurved and forming a sharp angle with the scarcely arcuated ventral. 2%..3.—Mediterranean. N. Fruviatiuis. Sow. G. f. 3.—Arca F. Schro. Flus. t. 9. f. 2.—Ch. f. 550, 1.—H#. t. 309. f. 7.—N. Rostrata. Lam, 2.—Arca R. Gimel. 3308.—(in part.) D. p. 245.—W. t. Jj. 43. Transversely oblong, rather convex, thin, transversely striated, posterior side rounded and more than twice as short as the anterior which is attenuated beaked and its very narrow ex- tremity obtusely angulated; anterior dorsal line nearly straight, oblique : ventral edge rather arcuated. 34..14.— Baltic, N. Seas. N. Minuta.* Turt. B.p. 178.—Arca M. Gmel. 3309.— Mont. p. 140.—D. p. 245.—W. t. 10. f. 44.—A. Caupara. Don. t. 78.—Tenuisutcata. Couth. (fide Gould.) Oval, trans- versely striated, white, with three or four concentric ridges, the anterior side produced curved and truncated: beak very small 1 This is not the Arctica of Gray in Parry’s voyage. TRIBE ARCACEA. = ~ 169 with a smooth dorsal area reaching thence to the anterior ex- tremity.— England. N. Parva. Som. in Conch. Ill. f. 7.—Reeve. t. 85. f. 7. Oblong, white, thickish, with an olivaceous epidermis, transversely grooved ; posterior side rounded, anterior rather beaked, angular : dorsal area anteriorly not grooved. ;3,..3.—WN. Pole. N. Pouira. Son. Z. P. 1832.—C. I. f. 11.— Reeve. t. 85. f. 11. Oblong anteriorly beaked, white under a polished greenish epidermis, anterior dorsal edge, smooth; with some oblique an- terior striae. =%,.. 144,.—Panama. N. Cosrexuata. Sow. Z. P. 1832.—Con. Il. f. 238.— Reeve. t. 85. f. 8. Oblong, thin, covered with small concentric acute riblets; anteriorly beaked and acuminated, with two dorsal approximated and crenulated ribs. 1..4+—Panama. N. Grpposa. Sow. Z. P. 1832.—Reeve. t. 85. f. 9.—Con. Il. f. 9. Oblong, gibbous, anteriorly acuminated and beaked, transversely grooved; anterior dorsal edge depressed, with the central margin elevated. 3..11.—Peru. N. Evenensis. Sow. Z. P. 1832.—Reeve. t.85. f. 14.—Con. Il. f. 14. Ovate, gibbous, transversely grooved, anteriorly acumi- nated and beaked; anterior dorsal margin arcuated, the margins erenulated. J,..4.—W. Colombia. N. Esurnea. Sow. Z. P. 1832. Ovate gibbous, transversely grooved, glossy, ivory-like, anteriorly acuminated and_beaked. y+ -43.—W. Colombia. N. Cuneata. Sow. Z. P. 1832.—Reeve. t. 85. f. 15.—Con. Il. f. 15. Ovate, wedge-shaped, gibbous, concentrically grooved, the epidermis greenish, glossy, the posterior side rounded the anterior acuminated. 4.. 2.—Valparaiso. N. Turocarormis. Storer. Bost. J. of N. H. 2.—Gould. Mas. f. 66. Large, oblong ovate, gaping at both ends, posteriorly rounded and shorter, anteriorly broader and obliquely subtruncated so that the dorsal extends further than the ventral edge; a rib-like wave passes from the beaks to the ventral anterior angle: cuticle dark olive green : hinge with a very large spoon shaped tooth on each side of which are twelve teeth, each one folded from the centre to an angle of forty-five degrees : inside polished white. 143.,24.— North America. N. Ereutsir. Couthouy Annals Lyceum, N. H.—Say. Cat. t. 1. f. 12, 3. Subelliptical, glossy, convex, moderately thick, sub- equilateral, posterior side rather longer; anterior side very slightly and obtusely rostrated ; ventral edge entire, much arcuated; dorsal edges but little sloping, the anterior subincurved, the posterior con- vex : cuticle blackish olive, marked only by the prominent lines of growth ; no anterior depression: inside dull bluish white; hinge broad, teeth few and obtuse, cardinal pit triangular. +..14.—Jn 170 TESTACEOUS MOLLUSCA. the specimen before me three or four granular lines radiate down the posterior slope.4 N. Recurva. Conr. Jour. A. N. S. Phil. 6.t. 11. fi 21. Oblong, concentrically striated towards the beaks, and obliquely so towards the ventral edge: anteriorly rostrated and recurved, posteriorly rounded, beaks subcentral. 4.— West Indies. N. Saporitia. Gould. Mas. p. 100. f. 61. Elongated ovate, translucent, subequilateral, posteriorly rounded, anteriorly narrowed and compressed; the anterior dorsal edge straight and rendered sharp by the compression of a very narrow portion of the margin ; subrostrated, tumid at the beaks with only a slight flexure under the anterior tips; smooth, polished, pale yellowish green: teeth about sixteen on each side. 4..-9,.— North America.® N. Navicutaris. Couthouy. Bost. Journ. N. H. 2. t. 4. SF. 4.—Gould. Mas. p. 103. Small, smooth, fragile, subequilateral, greenish yellow, posteriorly rounded, anteriorly feebly beaked ; slightly truncated, ventral margin very convex; beaks prominent ; inside white and glossy, the hinge with from sixteen to eighteen teeth. +.—North America. N. Nasuta. Sow. in Conch. Il. f. 12.—Reeve. t. 85. f. 12. Oblong, white, very finely striated transversely; posterior side rather shorter than the anterior, rounded: anterior acuminated, slightly turned upwards, with an elongated transversely striated dorsal area. 2..4.—Last Indies. N. Fasuta. Som. Conch. Il. f. 13.—Reeve. t. 85. f. 13. Ovate, white, obliquely striated, nearly equilateral, posterior side rounded, anterior acuminated, slightly turned upwards, with two ridges passing from the umbones to the acuminated extremity, the upper of which is crenated, forming an anterior dorsal area. I racpege q seiee N. Srrrata. Sow. Conch. Il. f. 16.—Reeve. t. 85. f. 16. Ovate, white concentrically striated, nearly equilateral, the dorsal slopes nearly equal; posterior side slightly acuminated, rounded ; anterior side acuminated, with an indistinct dorsal area. 2 ..44.— China. N. Mavritrana. Sow. Conch. Lil. f. 17.—Reeve. t. 85. f. 17. Ovate, white, concentrically grooved, nearly equilateral, posteriorly rounded, anteriorly acuminated: dorsal slope nearly equal on both sides. }.. 2.—Mauritius. N. Limatuua. Say. Am. Conch. t. 12.—Gould. Mas. p. 98. 1 Add likewise the N. Guacrauis. Gray. in W.S. t. 2. f. 6. 2 See too the Myauis of Couthouy in Boston. J. of N. H. 2. t. 3. f. 7.— Gould. p. 99. TRIBE ARCACEA. LAl Jf. 62. Oblong, very smooth and shining, subequilateral, cuticle light green occasionally with darker zones, and two or three lighter radiations : anterior dorsal edge rectilinear nearly to the tip, which is a little recurved pointed and not truncated: ventral edge scarcely at all imcurved: inside bluish white, subnacreous, twenty-two posterior, eighteen anterior teeth. =°,..1-9,.— United States. SLE NE Upite. N. Marearitacea.* Lam. 6.—Philippi. p. 64. t. 5. f. 8. —Sow. G. f. 7. (good.)—Arca M. Brug. Dic. p. 109.— Arca Nucuevs. Lin. 1143..—D. p. 244.—Brooks. Intro. t. 3. f. 36.—Da Cost. t. 15. f. 6.—Petiv. t. 17. f. 9.—Gualt. t. 88. R.—W. t. 10. f. 42. Ovate subtriangular, moderately convex, nearly smooth, some extremely fine radiating strice being indistinctly visible near the crenated ventral edge; cuticle olive-yellow ; umbones prominent ; ventral edge rounded ; anterior side much the longer, its dorsal edge moderately sloping ; posterior edge all but direct (but not abrupt), convex: beaks acute and re- curved: lunule defined by a shallow groove, inside pearly, hinge with numerous straight sharp pectinated teeth An. Var? (N. Pou? Phil. p. 63. t. 5. f. 8.) Larger, more oblique and triangular, olivaceous, with ridges of growth, posterior edge abrupt, anterior more sloping.—Lngland, France, Sc. N. Decussata. Sow. Conch. Il. f. 18. Somewhat. tri- angular, white, decussately striated; posterior side shorter, its slope rather elevated in the middle; anterior side much longer, oblique ; ventral margin rounded, its edge crenated. 3..47,— Guinea. N. Rucurosa. Sow. Conch. Il. f. 19. Ovate triangular, with a greenish epidermis covered with rugulose strie; angles obtuse: posterior slope with a central elevation; anterior slope somewhat rounded ; ventral margin very finely crenulated. ~2.. 4. N. Niripa.* Son. Conch. Il. f. 20. Ovate, subtriangular, smooth, shining, white with an olive coloured epidermis: anterior slope somewhat rounded, posterior nearly straight, with a central elevation. 2..4. N. Ostrava. Lam. 5.—Sow. Cone. Il. f. 21. Obliquely ovate, subelliptical, thin, pellucid, olive, smoothish ; posterior side rounded, rather long in proportion to those of this division, its edge convex: anterior side rounded, its dorsal edge much arcuated, the margin very entire. }..3.— Valparaiso, South Seas. N. Tenvis.* Zurt. B. p. 177.—F. p. 402.— Gould. Mas. p. 105. f. 64.—Arca T. Mont. Sup. p. 56. t. 29. fi 1.— Pen. 4. p. 215.—D. p. 246.—Turt. D. p. 11.—W. t. 10. f. 45. Ovate-trapezoidal, thin, smooth, without radiating lines, glossy grass green; anterior dorsal line scarcely sloping, nearly bole 172 TESTACEOUS MOLLUSCA. parallel to the but slightly arcuated and entire ventral, forming an angle at its extremity and by a broadly rounded curve, united to the ventral (the tip is therefore not angular but very obtuse); beaks prominent, recurved, having a deep pit before them; pos- terior side extremely short; teeth very long and slender, about eight anterior and four or five posterior. -=3,..4.—ngland, 5 North America. N. Convexa. Sow. Conch. Il. f. 22. Ovate, turgid, whitish smooth, posterior side the shorter, slightly acuminated ; anterior side much longer: dorsal slope rounded; ventral margin entire ; hinge pit very oblique, teeth of posterior side very few. 2..144.— China. N. Pisum. Sow. Z. P. 1832.—Sow. Con. Il. f. 23. Small obliquely oval, the posterior side very short, the dorsal margin inclined. +..4.—Valparaiso. N. Exteva. Sow. Z. P. 1832.—Con. Il. f. 24. Small, obliquely ovate, whitish pellucid, concentrically grooved ; anterior side the longer, subacuminated, the posterior extremely short. 35 --2-—W. Colombia. N. Proxima. Say. Jour. A. N. S. Phil. 2. ». 270.— Gould. Mas. p. 104. Subtriangular, oblique, concentrically wrinkled, with numerous minute longitudinal striz, posterior margin very short and very obtusely rounded, a submarginal im- pressed line; anterior margin very oblique, and but slightly arcu- ated: umbo placed far back: inner edge strongly crenated ; teeth stout, posterior row very distinct and regular. j.—U. States. Very like Nucleus but wider, and the posterior row of teeth more regular. TRIBE TRIGONIACEA. Primary, lamelliform and transversely striated teeth . TRIGONIA. Equivalve, inequilateral, trigonal, and sometimes orbicular ; teeth of the hinge oblong, laterally compressed, diverging, with trans- verse furrows ; two in the right valve grooved on both sides ; and four in the left valve, grooved on one side; ligament mar- ginal and external. T. Pectinata. Zam.—T. Mareariracea. An. du. Mus. t. 67. f. 2.— Son. G. f. 1, 2.—Bl. t. 70. f. 1.—Reeve. t. 86.— Cuama P. W.S.t. 2. f.6. Suborbicular, longer than broad, with radiating roughish verrucose and elevated ribs ; margin plaited. 1.—New Holland. TRIBE NAYADES. 173 CASTALIA. Equivalve, inequilateral, trigonal ; the umbones decorticated, and inflexed before; hinge mith two lamellar transversely striated teeth, one posterior, remote, abbreviated and subtrilamellar ; the other anterior, elongated, and lateral ; ligament external. C. QuapRILATERA. D’Orb. Am. t. 73. Subquadrilateral, inflated, thick, brown, when young entirely covered with broad flat elevated ribs (which in the adult disappear near the margins) beaks prominent, and posteriorly recurved ; anteriorly with a prominent keel having the appearance of an acute angle : inside brilliant white, only the anterior tooth striated, the cardinal being infinitely divided. 1,—S. America. C. Ampicua. Lam. 1.—TreTrrapLtopon Pecrinatum. Spia. Braz. t. 25. f.3, 4. Ovate-angular, inflated, trigonal, brown, pos- teriorly short, the beaks not recurved, anteriorly with a rounded keel, at the beaks covered with irregular carinated ribs : shining white, teeth striated. 13..21.—S. America. C.Inruata. D’Orb. Am. t. 72. f. 4. to 10. Ovate, very inflated subquadrilateral, very thick, greenish brown, with strong ribs at the umbones and usually transverse strize ; beaks prominent : posteriorly very short and rounded; anteriorly elongated, smooth, having the appearance of two prominent obtuse angles: inside bluish white, teeth striated. 11..12.—S. America, Guiana. TRIBE NAIADES. Shells inhabiting fresh waters ; the hinge sometimes having an irre- gular, simple, or cleft tooth, and a longitudinal, prolonged one, and sometimes none whatsoever, or having irregular granulated tubercles the whole length of the upper part ; a compound pos- terior muscular impression; the umbo usually decorticated. UNIO. Shell transverse, equivalve, inequilateral, free ; umbones decorti- cated, and somewhat worn ; posterior muscular impression compound ; hinge with two teeth in each valve; the cardinal tooth short, irregular, simple or cleft, substriated ; the lateral elongated, compressed and produced when aged ; ligament external. 1The outline of Mr Lea’s Synopsis of the Uniones has been - filled up in this monograrh. : Vv 174 TESTACEOUS MOLLUSCA. Division A.—Unio PropeEr. With a cardinal and lateral tooth. Section A.—SymMpnHonore.! U. Inrtatus. Lea.—Symprnonora I. Lea’s Unio. vol. 1. p. 109. t. 14. Triangular ovate, inequilateral, ventricose, very thin, elevated into a broad high wing posteriorly, a small one an- teriorly, both connate; cardinal tooth single in both valves, lateral teeth bladed towards their termination; beaks slightly prominent ; ligament concealed ; nacre purple, cuticle brown with obsolete rays. 22,.43.—R. Alabama. U. Auatus. Say.—Lam. 28.—Swain. Ex. C. t. 7.—Lea on U.1.p.62.—Mya A. W.S. f.3. Triangular ovate, transversely wrinkled, rather compressed, moderately thick, elevated into a high wing and connate over the ligament; beaks scarcely prominent, cardinal tooth double in both valves, lateral tooth double in the left valve only and slightly curved : ligament concealed, nacre purple. 475. .6,%.—N. America.? U. Lavissimus. Desh. in Lam. 6. p. 558.—Sympenonota L. Lea. on U. 1. p. 58. t. 13. f. 23. Subtriangular-ovate, inequi- lateral, subventricose, finely wrinkled transversely, shining, thin, with two not very high wings, the anterior the larger, both con- nate ; beaks scarcely prominent; ligament concealed; cuticle purplish brown, nacre purple and irridescent: cardinal and lateral teeth forming a curved line. 22%,.43.—Ohio. U. Graciztis. Barnes in Sil. Am. J. 6.—Symrpn. G. Lea.— U. Puanus. Barnes.—U. Fraciuis. Swain. Z. Il. vol. 3. Sub- triangular-ovate, inequilateral, transversely wrinkled, rather com- pressed, thin, anterior dorsal edge connate, wing but little elevated, beaks scarcely prominent ; ligament concealed ; nacre pearly, violet-purple, irridescent, cuticle yellowish green. 2}! .. 334,.— Ohio. U. Compressus. Lea.—Sym.C. Lea on U.1. p. 64. t. 12. f. 22. Transverse, much compressed, elliptical, inequilateral, thin, posteriorly rounded, beaks slightly elevated, not decorticated, crowned with small double concentric elevations, tips almost white ; anterior dorsal edge rather elevated and angulated at its extremity : cuticle olive green with broad rays all over the disc, nacre pale salmon becoming bluish near the margin ; cardinal tooth promi- nent, lateral small. 24..17%5.—Ohio. 1'To this division belongs the genus Hyrtia of Lamarck. 2 Add likewise the Lymnanp1A GicGas of Swainson. TRIBE NAYADES. We NI Or Section B.—Non-SyMPHONOTE. * Plicated. U. NicxuinrAnus. Lea. Tr, Am. Ph. 5. t. 1. Subtriangular, inequilateral, very thick, oblique, very much spread out, with an elevated wing, flattened towards the beaks, very much undulated even to the point of the beak (except near the anterior and ventral edges) ; cuticle dark brown, nacre pearly white ; teeth very thick, the lateral curved. 5..54.—China? U. Caratus. Conr. N. F.W.S. of Am. p. 29.t. 3. fi 4. Subtriangular, very inequilateral, rough, much compressed, with a broad furrow from the beaks to the base, (except the umbo and posteriorly), covered with small irregular interrupted undulations which are profound behind the umbonal slope, with distant slight concentric grooves; umbones much flattened, beaks prominent ; cuticle dark olive, obscurely rayed, nacre white and irridescent : teeth thick.— Tennessee. U. Heros. Say.—U. Muutiericatus. Lea. on U. 1. p. 80. t. 4. f. 2.—U. Licgamentinus. (old) Lam?—Unov- LAtus. Say. Am. Con. t. 16. Trapezoidal, inequivalve, trans- verse, compressed ventrally and anteriorly, very thick, adorned except posteriorly with broad undulations diverging from the um- bonal slope, those near the carinated dorsal edge curving towards it; beaks slightly prominent, the umbones flattened: ligament large long and curved ; cuticle black and much wrinkled, nacre pearly white and irridescent : cardinal teeth thick, lateral long and curved. 34..53.—Ohio. U. Unputatus. Barnes. in Sil. J. 6. t. 2. f. 2.—U. Cos- ratus. Conr. Mon. U.t.7. Rhombic-ovate, thick, with nume- rous large waving oblique folds (except on the posterior side which is very short obtusely rounded and merely marked by the transverse wrinkles which become lamellar anteriorly); cuticle blackish brown; nacre pearly white, irregularly spotted with brownish green ventral edge little arcuated, not incurved: beaks not pro..nent, eroded: cardinal teeth very thick, direct, sulcated. 32. .43.—Ohio. U. Puicatus. Say. in Ency. Amer.—Barnes. § Hildr. in Sil. J—U. Pervuviana. Lam. 4.—Rarapuicata. Lam. 5.— Domperana. Valen. in Humboldt. Voy.—U. Unpnutatus & Moutriexticatus. Desh. Suboval, thick, ponderous, with two or three more conspicuous undulations, which are profound very oblique continued to the anterior ventral edge and not arising from the decorticated umbo : nacre pearly. 176 TESTACEOUS MOLLUSCA. U. Trapezorwes. Lea. on-U. 1. p. 79. t. 3. f. 1—U. InteRRUpPTUs. Say. Ann. C. t. 33.—U. Crassipens. Var. A. Lam. 3. Trapezoidal, inequilateral, thick, transverse, ante- riorly angular above and below, posteriorly obliquely rounded ; anterior portion with oblique subparallel large plaits, its slope large and keeled; beaks slightly prominent, incurved: cuticle black and wrinkled, nacre purple and irridescent: cardinal teeth double in both valves, lateral, curved, and lamelliform. 22. . 4,35. — Louisiana. U. Foxiatus. Hildreth. in Sil. J. 14. f. 16.—U. Fuex- vosus. Conrad. in text.—Four1atus in plate 4 Monog. Com- pressed and shaped like a grape-leaf, the posterior ventral margin having a projecting lobe, on either side of which the edge is incurved anteriorly, rounded posteriorly, beaks flat and eroded, ligament more elevated than the beaks and passing between them ; dorsal margin curved: two elevated ridges from the beaks pro- jecting on the anterior dorsal and ventral margins: cuticle dark olive, waved transversely, and obscurely rayed with green across the waves: cardinal teeth small, that in the right valve deeply ‘suleated, the lateral teeth short and thick: nacre greenish white. 2.—United States. U. Puicirerus. Lea.on U.2.p. 61. t. 17. f. 53. Elliptical, inequilateral, somewhat inflated, with numerous small folds on the anterior side and slope, thicker posteriorly: ligament short and light horn coloured, cuticle blackish green, nacre purple: teeth rather large, the lateral straight. 14. .2;!,.—Mewico. U. Muttistriatus. Lea. on U. 1. p. 101. t. 12. f. 22. Subrectangular, transverse, inequilateral, slightly compressed and rounded nearly alike at both ends, rather thin; beaks slightly prominent, surrounded by wrinkles forming acute angles with each other: ligament linear; cuticle dark brown and wrinkled, nacre bluish white: cardinal tooth oblique, lamelliform, single in the left and double es he aeu valve, the lateral long and nearly straight. 1... 13,.-— Brazil. U. Susrentvs. Say. J. A.N.S. Phil. 5. §& Am. Con. t. 15. Oblong-oval, subcompressed, slightly contracted at the middle of the base, dull yellowish brown; beaks not prominent, decorti- cated: dorsal edge regularly arcuated, without any appearance of an angle: anterior margin with numerous slightly reflected ribs. 13..34.—North America. U. Conrapicus. Lea. Trans. Am. Ph. 5. t. 9. fi 23. Elongated-elliptic, transverse, rounded and short posteriorly, attenu- ated anteriorly, ligamental edge straight, ventral entire and little 1 Lamarck’s CastaL1 belong to this section: TRIBE NAYADES. 177 arcuated; thin, indistinctly folded on the anterior parts, beaks finely undulated at the tip: cuticle finely wrinkled, yellowish brown with numerous indistinct greenish rays which anteriorly are disposed to be clouded; nacre white posteriorly, anteriorly irri- descent, brownish purple in the cavity: cardinal teeth small and erect, the lateral ill defined. +.. 14. U. Acutisstmus. Lea. on U. 1. p.99.t. 10. f. 18. Small, narrow elliptical, inequilateral, transverse, very thin, acutely angu- lated anteriorly, with undulations diverging from the umbonal slope; beaks slightly prominent ; ligament linear; cuticle yellow smooth and shining, nacre salmon coloured ; cardinal teeth small, the lateral long and straight. $..151.—R. Alabama. U. Murcaisonianus. Lea. Trans. Ph. Am. 5. t.3. f. 6. —U. Doverasiz. Gray. Narrow-elliptical, transverse, thin- nish, angular and produced anteriorly, ligamental edge straightish, ventral edge incurved, beaks and umbones plicated, umbonal slope subcarinated and rough with the angles of the folds; ligament narrow and yellow: cuticle dark green, nacre splendidly pearly, slightly salmon coloured and irridescent : cardinal teeth double in both valves, the lateral straight. 4#..1-9,.—China. U. Grayanus. Lea. Trans. Am. Ph. 5. t. 9. fi 26. Lanceolate, very transverse, thin, rounded posteriorly, very produced and very acutely angular anteriorly, plicate about the beaks and the anterior «side, flattened on the sides, ventral edge slightly incurved in the middle and little arcuated; umbonal slope ridged, green, the beaks depressed: cuticle yellowish with obsolete rays, nacre pearly and irridescent: cardinal teeth double in both valves and erect, the lateral very long thin and nearly straight. +4..3,3,.— China. U. Ponperosus. JZca.—Mya P. D. p. 51.—Mya Crassa. Wood. G. C. t. 20. f. 21.—W. t. 2. f. 28. Ovate, ponderous, narrow anteriorly and truncated towards the cartilage slope, the beaks decorticated ; cuticle dark brown, longitudinally wrinkled in two different directions: primary tooth very strong shutting into a corresponding cavity. 3}..6.—China. * * Nodulous. U. Lacurymosus. Lea. on U. 1. p. 14. t. 6. f. 8. Sub- quadrangular transverse, rather depressed and rounded posteriorly, thick, anteriorly angular above and below: beaks recurved, approxi- mate ; not decorticated, covered with delicate raised points which radiate and enlarge in tear-like drops, leaving however untouched an oblique channel running anteriorly to the ventral margin; cuticle yellowish green, very smooth, posteriorly slightly rayed, nacre pearly white and silvery. 14%,.. 14.— Ohio. N 178 TESTACEOUS MOLLUSCA. U. Asperrimus. Lea. on U. 1. p. 81. t.5.f.3.—Tr. Am. Ph. 4.t.5.—U. Quaprutus. Say. Am. Con. t. 53. Subquadran- gular, thick, inequilateral; anteriorly biangular, with a broad smooth obtuse keel from the elevated beaks to the ventral margin, the slope and also the posterior edge of the keel nodulous: cuticle fuscous (in the young, yellowish brown with obsolete rays) nacre pearly and irridescent : cardinal teeth very large, lateral large and nearly straight. 33..44.—Ohio. U. Pracosus. Conr. Mon. U. p. 12. t. 6. f. 2. Suborbicular inclining to subquadrate,subequilateral, ventricose ; anterior margin direct and obtusely forming an angle with the oblique and nearly straight ligamental edge; with an indistinct narrow furrow (form- inga deep sinus at its termination) and two approximate series of very prominent irregular tubercles, anterior slope slightly concave, with a few narrow rib-like tubercles more prominent near the margin ; umbo narrow, prominent ; beaks much incurved, pointed, tuberculated : cuticle brown, usually with two or three broad, widely interrupted green rays. 2..23.—Ohio. U. Patuipst1. Conr. Mon. t. 5. f. 1. p. 9. Subovate, pos- teriorly rounded ; anterior side narrowed angulated above and below with a wide furrow and a few small tubercles, extremity subincurved : umbonal slope straight, subcarinated and tubercu- lated; anterior slope concave, indistinctly tuberculated ; ligamental edge oblique, rectilinear : ventral edge swelling centrally incurved in front ; cuticle yellowish brown, with indistinct filiform rays over the rather prominent umbo, disc with a single row of irregular tubercles in the centre, some of which are elongated and grooved : inside white, cardinal teeth rather small, direct, double in each valve. 12..2.—R. Wabash, N. America. U. Pusruzatrus. JLea.on U. 1. p. 89. +t. 7. f.9. Rounded- obovate, transverse, equilateral, inflated, thick, simply rounded posteriorly, the granulated anterior and the anterior ventral edge incurved : with two vertical rows of tubercles, one nearly central, the other along the umbonal slope; beaks elevated, ligament short and thick; cuticle yellowish brown, nacre white and irridescent : cardinal teeth large, lateral short and straightish. 159,. . 2;1,.— Ohio. U. Scnootcrarrensis. Lea. Tr. Ph. Am.t. 3. f. 9.—U. Prasinus. Conr. Transversely obovate, compressed, thickish, slightly tuberculated behind the umbonal slope, anteriorly longer and angulated above and below; beaks elevated, ligament short : cuticle yellow with the rays green and broad (particularly the central one) ; nacre pearly white and irridescent; cardinal teeth elevated, the lateral straight and lamellar. 1-1,..1,3,.—W. America. U. Aricutatus. Say. Am. C. t. 52. Subquadrate, the dia- meters subequal, obtusely subangulated, compressed and rather TRIBE NAYADES. 179 longer at the anterior side whose margin is generally retuse ; pos- terior side simply rounded, ventral margin incurved before the middle; yellowish or brownish olive, the entire surface studded with small subequal more or less rounded or transverse protube- rances arranged in lines which in front of the strongly raised umbonal ridge incline towards the ligament and anterior margin, are angulated in the groove and on the middle, and thence curve posteriorly : umbones not very prominent; within pearly white, irridescent anteriorly. —N. America. U. Asper. Lea. on U. 1. p. 95. t. 9. f. 15.—Tr. Am. Ph. 4. t. 9. f.15. Subquadrate, broader than long, inequilateral, ante- riorly angulated, thick, covered with small rough tubercles except in an oblique furrow from the beak to the ventral margin which is there arcuated ; beaks slightly prominent ; ligament short and thick : cuticle brown and wrinkled, nacre pearly white ; cardinal teeth rather large, lateral slightly curved. 12..14.—R. Alabama. U. Dorreviniianus. Lea. on U. 2. p. 73. t. 17. f. 54. Sub- triangular, inflated, tuberculated, inequilateral, very thick ; beaks large, very prominent, recurved : ligament short and thick : cuticle dark brown and transversely striated, nacre white; dorsal edge anteriorly very oblique, posteriorly very short and deeply incurved : cardinal teeth large and erect, lateral short andcurved. 23.. 2,9. — Ohio. PU esrarns) ed, on OO 9287 tl 7. of 8. Pro AM ate D, Jf. 8. Subtriangular, subequilateral, thick, rounded posteriorly ; anterior slope truncated undulated, nearly perpendicular, flat except just behind the short and thick ligament : posteriorly with trian- gular tubercles whose angle is directed ventrally ; umbonal slope tuberculated, the umbones flattened; cuticle yellow, slightly wrinkled, furnished with indistinct small pencil-like markings, nacre pearly white; cardinal teeth rather large, lateral distinct from the cardinal and pointing to the ventral margin. 1)..13.—R. Alabama. U. Meranever. Lea.—Con. Mon. U. p.10.t. 5. f. 2.—Raf. —U. Noposus (in. Sil. J. 6. t. f. 7.) and Rucosus. Barnes. Subquadrate, thick, ventricose, posteriorly rather shorter and rounded above and below ; studded except near the edge with large irregularly disposed tear-like tubercles ; anteriorly angulated above and below, the incurved edge obtusely forming a rectangle with the almost direct ligamental edge, ventral edge scarcely arcu- ated ; disc with an oblique radiating furrow; umbonal slope very prominent, broad, rounded, and rough with numerous tubercles (some very large): anterior slope wide, concave or angular, with oblique slightly recurved series of rib-like tubercles : umbo slightly prominent, beaks retuse: cuticle yellowish brown with interrupted green rays: within white. 13..2.—N. America. U. Cornutus. Barnes. in Sil. J. 6.t. 4. f. 5.—U. Rervexus. N 2 180 TESTACEOUS MOLLUSCA. Conr. Mon. t. 4. f. 1. Rounded-triangular, anteriorly angulated, posteriorly rounded and shorter, ventral edge well rounded, beaks somewhat elevated, with the ligament passing between them; anterior slope compressed, bounded by a roundish elevated ridge, marked by small transverse subnodulous wrinkles and obsolete longitudinal grooves: surface waved, a longitudinal row of large distant elevated transversely compressed tubercles divides the shell into two subequal parts: nacre pearly white and irridescent : cardinal teeth sulcated. 13..14.—N. America. U. Pusrutosus. Lea. on U. 1. p. 86. t. 7. f. 7. Quadrate, as long as broad, equilateral, inflated, anteriorly with large irregular long tubercles, thick ; beaks elevated and granular at the tip: liga- ment short and thick, epidermis bright brown with a single broad interrupted ray in the middle, nacre pearly white and irridescent : cardinal teeth rather large, lateral short thick and straight.— Odio. U. Turcipus. Lea.on U.2.. 11. ¢. 5. f. 11.—U. Morront. Conr. Mon. U. t. 6. f. 1. Subrotund, inflated, subequilateral, thick, subangular anteriorly, tubercles small crowded on the um- bones and scattered near the margin; beaks elevated, ligament short and thick : cuticle dark brown, nacre white and irridescent : cardinal teeth large and compressed, lateral short and nearly straight. 1-3, ..13.—New Orleans. U. Coorrrianus. Lea. Trans. Am. Ph. 5. t. 8. f.21. Sub- orbicular, transverse, oblique, thick, anteriorly much longer and irregularly tuberculated ; beaks thick and elevated ; ligament rather short and thick : cuticle wrinkled, dark rusty brown, rays scarcely visible, nacre flesh coloured and white ; cardinal teeth rather large, lateral rather short, thick and straight. 24..3!.—Ohio. U. Verrucosus. Barnes. in Sil. J. 6. t. 5. f. 6.—U. TuBERcu- Losa. Valen. in Humbs. voy. t. 53. f.2.—Tupercutatus. Conr. Mon. t. 22. Very inequilateral, thick, rounded posteriorly, biangu- lated and subtruncated anteriorly ; ligament deeply inserted between the valves ; hinge margin nearly straight, compressed, alated, heel- shaped, making an obtuse angle with the anterior ; ventral edge arcuated ; cuticle light green (usually tinged with reddish brown), studded anteriorly with irregular transversely compressed tubercles : cardinal teeth crenated or suleated: nacre brownish red with a tinge of blue or light chocolate (rarely pearly white,) slightly irri- descent anteriorly, posterior scar deep and rough. 147..1-%. U. Granirerus. Lea. on U. 2. p. 69. t. 19. f. 60. Subrotund, longer than broad, inflated, ponderous, sulcated on the anterior slope, tubercles not numerous rather small disposed to be erect and transverse ; beaks very prominent ; cuticle dark brown, nacre chocolate coloured ; cardinal teeth large, lateral short and straightish. 1,1, .. 2}.—Ohio. U. Noputosus. Lea.-Mya N. Wood. G. C. t. 22. f.1, 2, TRIBE NAYADES. 181 3, 4.—D. p. 52.—W. t. 2. f. 29. Suboval, thick, covered with tubercular knobs uniting into waved masses near the margin ; cuticle bottle green, umbones decorticated ; nacre pearly white, hinge with a clumsy strong crenated tooth ; scars deep, crenated. 2. U. Irroratus. Lea. on U. 1. p. 11. t. 5. f£ 5.—Tr. Am. Ph. 3.t. 5.—Katon.—Verrucosus Asus. Hildr. Suborbicular, longitudinal, inequilateral, extremely thick and swollen, dorsal edge rounded ; ventral rounded and slightly emarginated : beaks some- what elevated, recurved, decorticated ; cuticle really yellow but so covered with dark green radiating spotted lines as to appear olive ; discs transversely and deeply wrinkled, with a slight radiating furrow; tubercles slightly raised numerous and generally seated on the wrinkles : nacre pearly white and silvery : termination of the lateral tooth abrupt. 14..13.—Ohio. U. Dromas. Lea. Trans. Am. Ph. 5. t. 10. f. 29. Subtri- angularly suborbicular, suboblique, gibbous, very thick, very short posteriorly ; irregularly and transversely folded at the stages of growth, an oblique furrow before the umbonal slope ; beaks thick and elevated, ligament short and dark, umbones with a gibbosity ; cuticle yellow with numerous dark green dotted rays and posteriorly with about six rather broad ones, nacre pearly white: cardinal teeth wide, the lateral short and thick. 14.. 1,9;.— Tennessee. U. Msorus. Green. Cont. of Mac. Ly. 1827. t. 3.—U. Cicatricosus. Conr. (not Say.)—U. Varicosus. Conr. (not Lea.) Ovate, compressed attenuated and obtusely angular anteriorly, rounded and short posteriorly, ventral edge anteriorly sinuous : transversely striated and wrinkled on the disc; beaks decorticated and not prominent ;- a nearly central radiating gibbosity or nodulous ridge produced by the strice at that point becoming thick and tuberculated : cuticle glossy, tawny (in the young spotted and rayed with brown) nacre white and pearly: teeth thick and striated.—N. America. U. Varicosus. Lea. on U.1. p. 100. t. 11. f. 20.—Cricarri- cosus! Say. Subelliptical, oblique, thick, anteriorly compressed, varicose, with transverse concentric elevations ; beaks nearly terminal, elevated, incurved ; ligament long and large ; cuticle reddish brown, nacre pearly white: cardinal teeth rather small, the lateral long large and nearly straight. 3..41.—Ohio. U.Perptexus., Lea. on U.1.p. 122. t=. 17. f.42.—Tr. Am. Ph. 4. t.7.f.42.—Gissosus. Conr. Ovate, oblique, inequilateral, thick, having an irregular nodulous line near the middle which stretches obliquely from the beaks to the ventral margin: umbonal slope irregularly wrinkled, posteriorly to which is a wide slightly impressed furrow; beaks prominent rounded and close to the posterior end: ligament slender and rather long : cuticle smooth shining, yellowish, with numerous small crowded green rays cover- 182 TESTACEOUS MOLLUSCA. ing almost the whole disc, nacre milk white : cardinal teeth rather small, the lateral long and straightish. 1-9, .. 22.—Ohio. U. Granosus. Brug. Journ. H. N. 1. t. 6. f. 3, 4.—Lam. 37.—. t. 249. f. 2. Obovate, convex-depressed, reddish brown, anteriorly broader and rounded ; with oblique granular strie, the granules crowded : nacre bluish white. 12.— Guiana. U. Tusercutatus. Barnes. in Sil. J. 6. t. 7. f. 8.—Laton. —FHildr. in Sil. J. 14. Ovate-oblong, thick and rugged, anteriorly produced compressed attenuated and rounded at the tip, posteriorly short rounded and obtuse ; beaks flat and lower than the ligament : cuticle dark brown with longitudinally elongated tubercles, anterior slope bordered by a ridge from whence proceed deep and irregular nodulous undulations ; nacre white, cardinal teeth crenated, the lateral long and striated. 22..43.—N. America. U. Nova Houttanpiz. Gray. Z. P. 1834. Oblong-elon- gated, slender, solid: posteriorly subcompressed, smooth rounded ; anteriorly subventricose, produced, with large unequal tubercles disposed in curved radiating rows: the dise silvery and spotted with purple, the ventral margin posteriorly very thick: posterior cardinal tooth small, little elevated, bituberculated ; anterior teeth small and placed under the anterior edge of the cartilage: cuticle thick and black. River Macquarrie, New Holland. U. Cyuinpricus. Say. in Ene. Am. Nich. Conch. t. 4. f. 3.—-Haton.—Hildr.—U. Navirormis. Lam.— Reeve. t. 89. Transversely oblong, straight, posteriorly very short and rounded, ligamental edge very long and straight, ventral edge incurved in the middle; anteriorly angulated above and below and emarginate at the tip : beaks not prominent and as well as the anterior slope (which is bounded by a broad flattened umbonal ridge) undulated : cuticle yellow speckled with angular black marks, nacre pearly white, teeth crested. 14..3—Ohio. * * * Spimous. U. Sprnosus. Lea. on U. 2. p. 57. t. 16. f. 50.—Jay. Cat. ed. 3. pl. 5. Subtriangular, inflated, inequilateral, acutely angular anteriorly, thickish, beaks scarcely prominent, cuticle dark brown and shining, armed with afew long and thick spines: cardinal teeth inclining downwards, the lateral rather large and curved : nacre purple. 14..3-3,.—Georgia in America. * * * * Smooth. + Triangular. U. Arcawrormis. Lea. on U. 1. p. 126. t. 17. fi 44.— Nexus. Say. Am. C. t. 51. Subtriangular, very ventricose, 1 Add likewise the U. Legatr of Gray. TRIBE NAYADES. 183 transverse, inequilateral, very thick, posteriorly rounded, anteriorly attenuated and obtusely subangulated ; the beaks very broad, promi- nent and incurved ; anterior slope very wide and nearly flat, with a curved widening furrow, anterior ventral edge incurved; cuticle yellowish brown with numerous hair-like rays, nacre white : cardinal teeth thick, lateral short and straight. 2..21.—R. Tennessee. U. Trianeuraris. Barnes. Sil. J. 6. t. 13. f. 17.—KHat.— Hild.— Say. Am. C. t. 4.—Formosus. Lea. on U. 1. (male) p. 121.—T7. Am. Ph. 4. t. 17. f. 42.—Cuneratus. Sain. in Phil. Mag. 1823. Triangular, very convex, gaping at the extre- mities, the dorsal line forming a rectangle at the beaks, the ventral edge simply arcuated and subineurved anteriorly, extremitiesrounded ; anterior slope very much compressed ; beaks broad, pale yellowish olivaceous with green rays of interrupted lines and spots which are sometimes sagittate (disappearing near the margin in old specimens) ; longitudinal slightly elevated lines cross the transverse wrinkles. 14..13.—WNorth America. U. Exeegans. Lea. on U. 1. p. 93. t. 19. f.13.—T'r. Am. Ph. 4. t. 9.7.13. Subtriangular, transverse, subequilateral, thick but thinner and acutely angular anteriorly, flattened over the umbones : cuticle yellowish green with numerous rays formed of zigzag radiat- ing lines, nacre pearly white and irridescent, rarely rose coloured : beaks incurved, flattened and nearly touching: ligament short and thick : cardinal teeth large and elevated, the lateral nearly straight. 13..1,9— Ohio. U. Donacrrormis. Lea. on U. 1. p. 9. (§ Tr. Am. 3.) t. 4.f.3. Inequilateral, cuneiform, transverse, wrinkled, of moderate thickness pointed anteriorly, rounded posteriorly ; cuticle olive with green rays; nacre pearly white: beaks anteriorly angulated, not decorticated, almost touching: anterior dorsal edge subcarinated : cardinal tooth very prominent. 1..143—Ohio. U. Ziczac. Lea. on U. 1. p. 54. t.12.f.19.—Tr. Am. Ph. 3. Jf. 19.—Hat. Ovate, inequilateral, ventricose, thickish, not at all angulated : beaks rather prominent, often eroded ; ligament short and thick, cuticle yellowish covered with rays composed of fine zigzag green lines, nacre pearly white ; cardinal teeth large and erect, the lateral curved. ,9,.. 1$.—Ohio. U. Heteropon. Lea. on U. 1. p. 42.t. 8. f. 11.—TZr. Am. Ph.3.t.8.f.11. Rhomboidal-ovate, inequilateral, ventricose, thin, transverse, rounded posteriorly, anteriorly angulated and broader : dorsal edge straightish; cuticle wrinkled, greenish brown with oblique obscure rays, nacre white; beaks prominent: cardinal teeth compressed and white, the lateral slightly curved, the double tooth in the right valve. 39,..14.—Pennsylvania. UsWapruss (.Conr iN. WS. p.. 33s, 01 Sofi dy Ue- 184 TESTACEOUS MOLLUSCA. angular, very thick, ventricose, umbones flattened, beaks promi- nent and rounded, umbonal slope angulated ; anterior margin flat- tened, a broad convex elevation marked with radiating prominent lines (which dentate the margin) and concentric grooves projecting ventrally : cuticle olivaceous and wrinkled, nacre very white : liga- ment very short: cardinal teeth double in both valves, thick, prominent sulcated and granulated. 2}.—R. Alabama. U. Securis. Lea. on. U. 1. p. 51. t.11. f.17.—Hat.—v. Derressa. af. not. Lam. Subtriangular heart-shaped, in- equilateral, flattened over the umbones, thick; beaks elevated, recurved, much compressed : ligament shortish and thick : cuticle olive yellow passing into olive brown, shining and transversely wrinkled, nacre pearly white and irridescent. 14..1-9,.— Ohio. U. Cametus. Lea. Trans. Am. Ph. 5.t.15. f. 45. Trans- verse, subtriangular, thick; rounded, short and very attenuated posteriorly ; flattened over the umbones from the beaks to the ventral margin, which is little arcuated and incurved in the middle; anteriorly subcuneiform, cuticle yellowish brown with capillary rays, nacre white; cardinal teeth small, the lateral large thick and curved. 2.3, .. 32.— Ohio. U. Ovatrus. Say. in Enc. Am. Nich.—Lam.—Conr. Mon. 2. f. 1, 2, 3.—Barnes. Obovate, convex, not thick, deeply wrinkled, glossy, umbones prominent, epidermis yellowish or horn coloured, rayless ; anterior slope flattened and fuscous, some- what waved with stris, and wrinkles which become lamellar: hinge-margin making an angle with the anterior and posterior dorsal edges; nacre pearly, bluish white: beaks subcentral, recurved; teeth elevated, the cardinal compressed and crestlike. 2-3,..353,.—Ohio. ' U. Susovatus. Lea. on U. 1. p. 128. t. 18. f. 46. Sub- ovate, transverse, inflated, thick, inequilateral : beaks elevated, incurved and undulated at the tips; ligament short and thick : cuticle yellowish with numerous oblique green rays, nacre white and very pearly: cardinal teeth double in both valves and erect, the lateral short and lamelliform. 3. .41.--Ohio. U. Crassipens. Zam.—vU. Nicer. Conr. Mon. U. t. 26.—U. Cuneratus. Barnes. Elongated and subtriangular, ponderous, anteriorly narrowed wedge-shaped and compressed ; umbones somewhat elevated, beaks low and distant : anterior de- pression elongated, heart-shaped and furrowed, the ventral edge slightly rounded : cuticle blackish brown, somewhat ferruginous : an elevated ridge from the beaks anteriorly: nacre brownish purple and irridescent ; cardinal teeth deeply divided and sulcated, the lateral long curved and not thick. 2,3,..34.—North America. U. Carponarivus. Lea. on. U. 2.p. 37. (Sin Tr. Am, Ph.4.) TRIBE NAYADES. 185 t. 11. f. 32. Subtriangular, transverse, swollen, inequilateral, thick, ventral margin centrally incurved, anterior side rounded; beaks rather prominent: cuticle black and (apparently) without rays, nacre purple and irridescent : cardinal teeth rather large, lateral small and somewhat curved. 12..22.—Meaico. U. Gisper. Lea. on U. 2. p. 35. t. 10. f. 30. Triangular, compressed, inequilateral, transverse, anteriorly somewhat tri- angular and elevated on the dorsal edge, thickish, ventral edge centrally incurved : beaks rather prominent, ligament short, cuticle dark brown, (apparently) not rayed, nacre salmon coloured : car- dinal teeth small, the lateral inclined. 4. .14.— Tennessee. U. Pumitis. Lea.on U.2. p. 23. t.7. 7.17. Subtriangular, transverse, inequilateral, thinnish, anteriorly subbiangular and its dorsal edge straightish; beaks somewhat prominent: ligament short : cuticle dark brown, nacre white: cardinal teeth large, the lateral short and straight. +4. .1,.—N. Carolina. U. Rusiernosus. Lea.on. U. 1. p. 41. t. 8. f. 10.—Tr. Am. Ph. 3. t.8.f.10. Inequilateral, transverse, subventricose thickish, obovate, posterior and ventral edges rounded, anterior incurved, anterior dorsal sloping ; beaks prominent, incurved, anteriorly sub- angulated : cuticle rusty or salmon-yellow (wrayed when young,) nacre salmon coloured; cardinal tooth large, the lateral thick. 251, - 235-— Ohio. U. Barnesianus. Lea. on U. 2. p. 31. t. 10. f. 36. Sub- triangular, compressed, inequilateral thick: beaks rather promi- nent: cuticle chesnut brown with interrupted green rays and strong marks of growth; nacre white and irridescent: cardinal teeth small, the lateral nearly straight. 1..12.—T'ennessee. U. Piteus. Lea. on U. 1. p. 129. ¢. 18.f. 47.—Tr. Am. Ph. 4. t. 18. f. 47. Subtriangular, ventricose, thick, posteriorly rounded, angular anteriorly, longitudinally furrowed in front of the umbonal slope which is flattened on the ridge, the furrow causing a slight emargination on the ventral margin; beaks prominent and rounded at the tip: ligament short and thick: cuticle yellowish brown, wrinkled, rays numerous and hair-like, nacre pearly white and irridescent ; cardinal teeth large, lateral shortish and slightly curved. 1+4..14.—Ohio. U. Sowrersianus. Lea.— Trans. Am. Ph. 5. t. 10. f. 28. Subtriangular, thick, inflated, singularly compressed on the an- terior part which is filled with striz from the anterior and the anterior ventral edges, the posterior part being inflated and smooth ; slightly emarginate at anterior ventral edge: beaks large and very prominent ; ligament short and thick ; cuticle bright brown, smooth and shining behind, striate before, nacre very light purple; cardinal teeth large, the lateral thick and nearly straight. 15%, . . 14.— Tennessee. U. Triconus. Lea. on U.1. p.120. (f§ in Tr. Am. 4.) t. 16. 186 TESTACEOUS MOLLUSCA. f. 40. Subtriangular, inflated, subequilateral, depressed before the umbonal slope which is carinated, thick, anteriorly angular, the ven- tral margin emarginate : beaks prominent, incurved and slightly undulated at their tips: ligament short and thick : cuticle brown, rays obsolete, nacre pearly white and irridescent : cardinal teeth large, lateral large and slightly curved. 2 ., 2.3,.— Ohio. U. Soxipus. Lea. on U. 2. p. 13. (§ Tr. Am.) t. 5. f. 13. Oblique, inflated, very thick inequilateral : beaks very elevated and retuse ; ligament shortish and thick ; cuticle rusty green, (some- times obscurely rayed) nacre pearly white : cardinal teeth thick, lateral oblique and short. 1-%,..13.—Ohio. U. Osxiauus. Lam.—U. Unpatus. Barnes in Sil. J. 6. t. 4. f.4.—Triconus. Say. § Conr.—Corpvatvus. Conr. Mon. U.t. 25. Subtriangular, longer than broad, thick, very tumid, posteriorly obtuse and very short, anteriorly rapidly narrowed and angulated : beaks elevated and recurved, with the ligament passing between them ; ventral edge compressed in the middle ; cuticle horn coloured and glabrous, nacre pearly white : cardinal teeth deeply sulcated and crenated, two lateral ones in each valve. 21..2;1,.— N. America. U. Pyramipatus. Lea. on U. 1. p. 119. (§ Tr. Am. 4.) t. 16. f. 39.—U. Myritorpes. Faf.—Mya Osrieva. Wood. 8. t.2. f.8. Subpyramidal, longitudinal, inflated, oblique posteriorly thicker, swollen and very short, beaks very much elevated, recurved and incurved : cuticle dark brown and finely wrinkled, nacre flesh colour ; cardinal teeth large and crenated, the lateral long, distinct from the cardinal and pointing ventrally. 2,3, ..245.— Ohio. ++ Oblique. U. Troostensis. Lea. Trans. Am. Ph. 5. t. 10. f. 30.— U. Trapauis. Conr. Mon. U. p. 110. t. 60.f. 2. Oblong-ovate, yventricose, posteriorly short and rounded, anteriorly produced attenuated obtusely cuneiform, ventral edge slightly arcuated and entire: umbonal slope rounded, anterior slope flattened or concave (in old shells furrowed) ; beaks eroded and rather prominent ; cuticle smooth, polished, dark olive tinted with green, with dark green unequal rays: within dull white or slightly salmon coloured posteriorly, bluish and very irridescent anteriorly, cardinal tooth in one valve very thick and direct. 14..13.—N. America.) U. Tartianus. Lea. Tr. Am. Ph. 5. t. 4. f..11. Subtrian- gular, thick (particularly posteriorly), depressed posteriorly to the umbonal slope, beaks very thick and much elevated ; cuticle dark brown and wrinkled, nacre pearly white: cardinal teeth large and elevated, the lateral thick and slightly curved. 13..13.—R. Alabama. 1 Add likewise the U. Tigris of Ferussac. TRIBE NAYADES. 187 U. Cor. Conr. N. FF. W. S. p. 28. t. 3. f.3. Obliquely cordate, thick, with concentric furrows, a slight and broad depres- sion from the beaks to the base; beaks and umbones very pro- minent ; umbonal slope subangulated, submarginal ; posterior side short, subtruncated, anterior side flattened behind the umbonal slope: cuticle rugose, olivaceous with green interrupted rays (some broad), nacre white and irridescent: teeth much elevated granulated and suleated.—F. Alabama. U. Truncatus. Smain. Z. Il. 2d series. Thick oblong, the umbones close to the posterior margin which is truncated, anterior side produced and cuneiform, ventral edge little arcuated ; very convex, nearly smooth, cuticle fulvous, nacre pearly. 12. .33. U. Decisus. Lea.on U. 1. p. 102.—Conr. Mon. U. t. 3. f. 2. Very inequilateral, oblique, wedge-shaped, scaleniform and very thick ; anteriorly subacuminated, posteriorly obliquely obtuse and inflated : beaks elevated incurved, nearly terminal, generally decorticated ; ligament rather small; cuticle yellowish brown some- times with oblique indistinct brown rays, nacre pearly white ; car- dinal teeth smallish, lateral thick. 153,..31.—#. Alabama. U. Cuavus. Lam.—Conr. Mon. U. p. 5. t. 3. f. 1.—Monio- LiFoRMIS of Say. (not Lea.)—U. Scatenius. af. Ann. de Sc. Phy. 5. t. 81. f. 24, 5. Cuneiform, very oblique ; anterior side produced, compressed, with an oblique furrow rapidly widen- ing from the umbo; ligamental margin arcuated, very oblique ; umbo elevated, narrowed, inclining posteriorly, beaks curved to a point, terminal ; epidermis wrinkled, olive yellow or brownish with interrupted rays over the umbo, disappearing by age; inside white, irridescent anteriorly : cardinal tooth in the left valve, nearly parallel with the ligament margin. 1}..13.—WN. America. > Pavonus, Lea..0n tl. \. p..55.(¢ 1r.Am. 3.) t12. fF. a0. Ovate, compressed, wedge-shaped, inequilateral, oblique, transverse, compressed on the umbones, thickish, anteriorly attenuated, sloping from the beaks on both sides, posteriorly obtuse and very short : cuticle yellowish brown, wrinkled, with more or less broad inter- rupted rays, nacre pearly white; cardinal tooth small, the lateral long and slightly curved. 12..2,3,.— Ohio. U. Ravenevianus. Lea. Trans. Am. Ph.5.t. 3. f. 5. Trans- versely ovate, short and obliquely rounded posteriorly, subangu- lated anteriorly ; ligamental edge straightish, ventral little arcuated ; ligament short and thick; cuticle dark brown, finely wrinkled, nacre pearly white, partly irridescent; teeth thick, the cardinal short, the lateral straight. .°;. . 14.—Tennessee. U. Raneranus. Lea. on U. 2. p. 95. (f° Tr. Am. Ph.) t. 18. Jf. 56. Oblique,somewhat compressed, obovate, very inequilateral, thickish, anteriorly very broad, rounded at both ends, dorsal edge straightish, ventral subincurved in the middle: beaks prominent ; 188 TESTACEOUS MOLLUSCA. cuticle yellowish, covered with green rays, nacre white; cardinal teeth small, the lateral long and straight. 11..14.— Ohio. U. Suxtcatus. Lea. on U. 1. p. 44. (§ Tr. Am. Ph. 3.) t. 8. f. 12.—Eat.— Say. Am. Con. t. 5.—Rupisunpvus (female). Say. Am. C. t.5.—EHat. Subelliptic, short very thick, inequilateral, ventricose, ventral edge incurved anteriorly by an oblique hollow running from the beaks, which are nearly terminal obtuse eroded and prominent; cuticle olive brown, wrinkled, with numerous fine radiating hair-like lines, (except posteriorly), nacre purple: the teeth large and double in both valves. 1-45 . . 243;.— Ohio. U. Haysianus. Lea. Trans. Am. Ph. 5. t. 3. f. 7. Sub- rotund, transverse, subventricose, scarcely thick, subequilateral, but rather longer anteriorly, dentated at the anterior ventral edge, de- pressed before the umbonal slope ; beaks thick and elevated: cuticle yellowish brown, very smooth and shining, the rays obsolete, nacre chocolate : cardinal teeth lobed, the lateral smooth and straight. 4..1—N. America. U. Exurpsis. Lea. on U.1. p. 10. (f Tr. Am. 3.) t. 4. f. 4. —Hat.—Breviatis? Sow. Elliptical, ventricose, very thick, rounded at bothends ; beaks all but terminal, decorticated ; surface somewhat wrinkled, the cuticle smooth and reddish brown, the nacre pearly white and silvery, teeth large and well defined, the cardinal crenulated. 1,4, . . 2-3;-— Ohio. U. Castaneus. Lea.on U.1.p.101. (f§ Tr. Am. 4.) t. 11. f. 21. Obovate, transverse, thick, oblique, inequilateral, inflated, rounded at both ends, ventral margin very convex, beaks prominent, ligament short ; cuticle dark brown, becoming yellowish, with a few rays anteriorly, nacre very pearly and irridescent: cardinal teeth large, lateral short and straightish. ¢...1.—. Alabama. titi POval: U. Tamrrcoensis. Lea. on U. 2. p. 24. (§ Tr. Am. Ph.) t.7. f. 18. Ovate, transverse, inflated, subcarinated, inequilateral, thick, beaks somewhat prominent, ligament large and Jong: cuticle blackish and (apparently) rayless, nacre white and irridescent (rarely rose colour): cardinal teeth large, lateral long straightish and large. 24...4,3,.—Mexico. U. Lecontianus. Lea. on U.2.p.40.t. 12. f. 35. Ellip- tical, transverse, inequilateral, somewhat inflated, thick, ventral and dorsal edges straightish and subparallel, anterior side subbi- angular ; beaks slightly elevated ; cuticle yellowish brown and obscurely rayed, nacre pale salmon coloured, cardinal teeth small, the lateral long and separate. 1,1,..24.—Georgia in America. U. Pervix. Lea. Trans. Am. Ph. 5.t. 11. f. 31. Trans- verse, elliptical, inflated, thickish, anteriorly subangulated and rather longer, ligamental edge straight, ventral edge entire ; beaks TRIBE NAYADES. 189 slightly elevated and without undulations at the tip; ligament short and thick: cuticle yellowish covered with irregularly in- terrupted rays, nacre pearly white and irridescent : cardinal teeth elevated, the lateral larger near their termination. Tennessee. U. Pecrorosus. Conr. N. F. W. p. 37. t. 6. f.1. Oval, ventricose, not thick, anteriorly obtusely biangulated and longer ; umbonal slope subangulated, the space behind flattened, with an impressed line from the beaks to nearly the middle of the anterior margin: ventral edge arcuated and entire; umbones wide and prominent, beaks slightly elevated ; cuticle brownish olive rayed with angular spots, nacre white: cardinal teeth direct, subpyrami- dal, prominent. 3.—T'ennessce. -U. Venrricosus. Barnes. Sil. J. 6. t. 14. f. 14. Large, thick, triangularly ovate, transverse, convex, the umbones large round and prominent, the beaks recurved, and the cavity capa- cious : smooth, anteriorly very broad and subtruncated, anteriorly rapidly narrowed, ventral edge entire and arcuated ; anterior slope longitudinally waved: cuticle yellowish olive becoming chesnut brown on the umbones (rayed when young with green) nacre dull white, cardinal teeth broad, prominent and obliquely flattened, the lateral broad elevated and abruptly ending anteriorly. 34.. 42. —North America. U. Occipens. Lea. on U. 1. p. 49. (§ Tr. Am. Ph. 3.) t. 10. f. 16.—Venrricosus. Say. Am. 6. t. 32. Inequilateral, transverse, ventricose, thick, rounded at both ends, posteriorly very narrow, anteriorly very broad ; beaks large, rounded, approximate, prominent, subundulated and rarely decorticated : ligament rather short and thick: cuticle olive yellow with oblique greenrays, which are ‘more crowded anteriorly, nacre white: teeth elevated. 2,5,..3%. — Ohio. U. Dotasrezrormis. Lea. on U.2.p. 103. (& Tr. Am. Ph.) t. 24. f. 113. Elliptical, transverse, inequilateral, thick ; dorsal edge incurved, posteriorly much lower and angulated at its extremity, ventral edge straightish in the middle ; beaks inflated and prominent: umbonal slope somewhat carinated and obscurely rayed : cuticle brown and finely wrinkled, nacre white and irridescent : cardinal teeth somewhat lamellar, the lateral long and lamellar. 3..41.— Georgia in America. U. Guososus. Lea.—Symrnonota G. Trans. Am. Ph. 5.t. 4. f. 12. Transversely obovate, very globose, inequilateral, thinnish, pellucid, ventral edge much arcuated, hinge margin much curved and angulated at the extremities ; beaks very round, incurved ; cuticle very smooth and pale yellow, nacre pearly white and irridescent ; teeth lamellar, the lateral elevated. 23..33.— Ohio. 9 aes 15... 354: 190 TESTACEOUS MOLLUSCA. U. Sprenpipus. Lea.on U. 2. p. 70. t. 19. f. 61. Ellip- tical, very inflated, thickish, inequilateral, ventral edge somewhat rounded ; beaks prominent, anterior slope with three indistinct ribs ; umbonal slope carinated: cuticle yellowish covered with numerous dark green rays, nacre rosy; cardinal teeth somewhat compressed, the lateral separate and lamellar. 1,7,..24—eor- giaim America. U. Ocuracevs. Say. in Nic. Enc. Am. Cone. t. 2. f. 8.— Conr. Mon. U. t. 17. f. 2.—Sympuonora O. Lea. on U.1: p. 69. Subovate, inequilateral, transversely wrinkled, inflated, thin, connate before the ligament which is not concealed, not winged ; beaks full and prominent, with several concentric undu- lations: cuticle glossy, varying from yellow ochre to brown ochre, with oblique rays which anteriorly are more numerous, nacre bluish white and ochraceous ; cardinal and lateral teeth forming a curved line. 1,9, ..2,9,.—Delaware. U. Carrosus. Say. Ene. Am.—Am. C. t. 3. f. 2.—Barnes. —Lam.—vU. Lureota. Conr. Ovate or oval, not very thick, anteriorly longer, (and usually dilated) discs swelled, umbones elevated ; cuticle olive brown, or greenish, usually rayed with green, nacre bluish white, often white reddish rose or salmon ; ligament elevated : cavity moderate. 2,35 .. j5.—N. America. U. Perovatus. Conr. N. F. W. p: 47. t. 2. f. 3.—WSil. Jour. 25.t. 1. f. 3. Transverse, ovate, rather ventricose, thick but thinner on the anterior side, which is longer attenuated and ob- tusely subangulated above and below; ventrally and_ posteriorly rounded, beaks rather elevated, approximated and undulated : cuti- cle olive, wrinkled on the margin, nacre white: cardinal teeth erect and prominent, not very thick. 2.—R. Alabama. U. Aurinis. Conr. N. F. W.S. p. 43. t. 2. f. 1. Transverse, suboval, thin, inflated, beaks slightly prominent and much dilated ; anteriorly longer dilated and obtusely subangulated, ventral edge arcuated and entire, umbonal slope rounded, behind which is an obscure radiating rib: cuticle blackish, rugose, olivaceous over the umbones and rayed with short vermicular lines on the anterior slope, nacre whitish and irridescent ; cardinal teeth subpyramidal, erect, the lateral distant. 2.—Alabama. U. Muxttrrapratus. Lea. on U.1. p. 48. t. 9. f.15.—U. Fas- cious. Conr. Mon. U. t. 11. f. 2.—U. Ligamentina. Desh. Elliptical, transverse, inequilateral, ventricose, thin, anteriorly ob- tuse, posteriorly and ventrally rounded ; beaks prominent and slightly undulated, cuticle olive yellow covered with green rays, nacre bluish white: cardinal teeth erect and double in both valves, the lateral lamelliform and abrupt. 1;45.. 2.—Ohio. U. Novi Esoraci. Lea. on U. 2. p. 104. t. 24. f. 114. Ellip- tical, somewhat compressed, inequilateral, thickish, posteriorly TRIBE NAYADES. 191 obliquely rounded, ventral edge somewhat rounded : beaks some- what prominent, undulated at the tip; cuticle yellow with green rays nearly over the disc; nacre white and irridescent; cardinal teeth large and erect, lateral long and straight. 1 71,..21.—New York. U. Perovauis. Conr. N. F. W. S. p. 43. t. 2.f. 2. Shortish, oval, moderately thick, inflated, transverse, inequilateral: anterior side obtusely truncated obliquely, ventral edge arcuated and entire; umbonal slope rounded ; cuticle olivaceous, obscurely rayed, wrin- kled on the margins ; nacre whitish and irridescent anteriorly: teeth prominent and granulated.—Var. Reddish brown, nacre rosy. 2.—R. Alabama. U. CarsArormis. Lea. Tr. Am. Ph. 5. t.2. f. 4. Trans- versely elliptic, shorter and rounded posteriorly, subangulated above and below, anteriorly convex, ligamental edge straight, beaks slightly elevated, ligament short and thick; cuticle yellow with numerous short green rays, nacre white and irridescent anteriorly ; teeth elevated, the cardinal double in both valves, the lateral lamel- lar. 1.3,.. 195.-—N. America. U. Greenr. Conr. N. F. W.8.32.t. 4.f. 1. Subovate, trans- verse, thickish, posteriorly not very short rounded, ligamental edge sloping, obtusely angulated at its end; beaks slightly prominent umbonal slope straight, subangulated : cuticle wrinkled, olivaceous, rayed anteriorly ; nacre bluish white ; a short obtuse elevation pas- sing obliquely from beneath the cardinal teeth which are thick, the lateral striated and minutely granulated. 13.—#. Alabama. U.,Picrus. Lea. Trans... Am. PRES St. 11s f: 322° Trams? versely elliptical, dilated and produced anteriorly, thinnish; beaks compressed and finely undulated atthe tip, ligament short and rather thick ; cuticle yellow, with numerous oblique interrupted rays which are strongly pencilled at the commencement of each stage of growth, nacre pearly white and irridescent : cardinal teeth small, the lateral long and slightly curved. 13..23.—Tennessee. U. Taniatus. Conr. N. F. W.S8. 26. t. 4. f. 2. Transverse, regularly convex and elliptical, the beaks slightly prominent, the umbonal slope rounded, ligament slope with a slightly impressed line, ventral edge rounded: cuticle wrinkled olivaceous, with green interrupted rays, nacre bluish white, teeth prominent. 2.—Zi. Alabama. U. Interrvetus. Lea. on U. 2. p. 15. Transverse, elliptical, compressed, inequilateral, thickish, ventral edge rounded, posterior dorsal sloping; beaks somewhat compressed, rather prominent, the umbones flattened; ligament shortish ; cuticle yellow, rather smooth, covered with broad green interrupted rays, nacre white ; lateral teeth rather long and curved. 15. .23.— Tennessee. U. Menxianus. Lea. on U. 2. p.76. Elliptical, rather com- 192 TESTACEOUS MOLLUSCA. pressed, thinnish, inequilateral, ventral edge somewhat rounded : beaks somewhat prominent and undulated: cuticle fulvous, covered with numerous rather large green rays, nacre pearly white and irri- descent : cardinal teeth small and erect, the lateral long and nearly straight. 14..23.— Tennessee. U. Venustus. Lea. on U. 2. p. 4. t. 2. f. 4. Elliptical, transverse, somewhat compressed, inequilateral, thickish, dorsal edge posteriorly sloping, ventral posteriorly subincurved : beaks scarcely prominent: cuticle yellowish with green somewhat sinuous rays, nacre pearly white and irridescent: cardinal teeth small, the lateral rather curved. 1.. 144,.—Missouri. U. Crassus. Say. dm. C. t. 8.—Barn. in Sil. J. 6. f. 1.— U. Ligamentina. Lam.—E.uipticus AND Cartnatus. Barnes. —Mya Gravis. Wood. S.f. 6.—U. Fasciatus. Conr. Varying in form, usually more or less oval, very thick and tumid, light brown, rounded posteriorly, slightly angulated anteriorly : surface waved, beaks projecting, nacre pearly white and irridescent ; car- dinal teeth direct, very thick, lobed, angulated and deeply sulcated; posterior cicatrix deep and rough. 34..44.—N. America. U. Orsicutatus. Hildr. in Sil. J. 14.—Asrurtus. Say.— Crassus. Conr. Mon. U.t. 16. Suborbicular, anterior margin broad and slightly rounded, posterior short and narrow: discs much inflated ; ligament thick elevated and passing between the beaks, which are broad, somewhat elevated and directed backwards ; cuticle changing from dark chesnut on the discs to light brown, nacre flesh colour and irridescent: cardinal teeth elevated and angulated. 2}.—U. States. U. Austrratis. Lam. 46. Transversely ovate, subsinuated in the middle, lateral extremities rounded: cardinal tooth small, compressed, and rather acute. 21.—New Holland. U. Hypranus. Lea. on U.2.p. 14. t. 6. f. 14. Elliptical, transverse, very inequilateral, subinflated, thickish ; ventrally sub- incurved, rounded at both ends: cuticle yellow, covered with dark green rays, nacre white and irridescent: cardinal teeth elevated, lateral long and separate. 12..23.— Louisiana. U. Cuarrsornensis. Lea. on U. 2. p. 105. ¢t. 24. f. 115. Elliptical, subinflated, inequilateral, thick; beaks somewhat promi- nent ; ligament rather long and thin: cuticle yellow, smooth, with a few obsolete rays: nacre white and irridescent: cardinal teeth small and compressed, lateral long and lamellar. 1..1;5.—W. Alabama.— Clairborne. U. Lureotvus. Lam.—U. Sin1avorpes. Barnes.—Con. Am. 6. ¢. 10. f. 1.—Inruatus. Barnes. Elliptical, ventricose, mode- rately thick, glabrous, olive yellow, with numerous green rays vary- ing much in size; posteriorly rounded, not very short; anterior edge forming an angle with the almost direct and straight ligamental TRIBE NAYADES. 193 ventral edge simply arcuated ; umbones not prominent, umbonal slope undefined ; beaks with flexuous undulations; inside bluish white, cardinal teeth oblique, lateral slightly decurved anteriorly. 14..2}.—Delanare, §'c. N. America.t U. Putcuer. Lea. on U. 2. (and Tr. Am. Ph. 6.) p. 6. t. 3. J. 6. Elliptical, transverse, somewhat compressed, inequilateral, thickish, ventral edge rounded; beaks irregularly undulated; cuticle yellow, covered with numerous dark green well defined rays, nacre pearly and pink: cardinal teeth erect, lateral enlarged near their termination. 1,3,..21.— Tennessee. U. Rapratus. Zam. 13.—U. Virerniana? Lam.39.—Mya Rapiata. G'mel. 3220.—D. p. 51.—Mya Ostoneata. Wood. JS. 2.—Ch. f. 7. Obovate, thin, convex-depressed, very finely striated transversely, the anterior side very broad, cuticle yellowish and lon- gitudinally rayed. 23.—Sarratoga. U. Mevexunus. Lea. on U. 2. (and Tr. Am. 5.) p. 39. t. 12. f.34. Elliptical, transverse, rather compressed, inequilateral thinnish, ventral margin subineurved centrally ; much narrower and obliquely rounded posteriorly; beaks rather prominent, ligament rather long and slender: cuticle yellowish covered with green rays, nacre white and irridescent: cardinal teeth small, lateral long and somewhat curved. 153,..2,3,.—Vera Cruz. U. Norarus. Lea. on U. 2.(Tr. Am.6.) p. 28. t. 8. f. 22. Elliptical, compressed, transverse, inequilateral, anteriorly subbian- gular, thin, posteriorly obliquely rounded: beaks rather prominent : ligament shortish: cuticle reddish brown, covered with interrupted rays, nacre salmon coloured and irridescent : cardinal teeth small, lateral long and slightly curved. 1. . 14.—T'ennessee. U. Vanuxemensis. Lea. on U.2. (and Tr. Am. 6.) 11. f. 31. Elliptical, transverse, compressed, inequilateral, thick, ventral edge straightish, anterior edge incurved: beaks somewhat pro- minent: cuticle dark brown and (apparently) rayless, nacre salmon coloured and irridescent : cardinal teeth large, the lateral long and somewhat curved. 11..1-2,.—Tennessee. U. Nasuvinzranus. Lea. Trans. Am. Ph. 5. t. 14. f. 43. Transversely elliptical, thickish, posteriorly rounded and short, ante- riorly produced and subacuminated, ventral and ligamental edges little arcuated: beaks slightly elevated and minutely undulated ; ligament shortish : cuticle dark brown, obscurely rayed, nacre pearly white : cardinal teeth lamelliform and double in both valves, the lateral nearly straight. 1%..2}.—Ohio. ° U. Zrecierranus. Lea. on U. 2.(Tr. Am.6.) p. 32. ¢t.10. f- 27. Elliptical transverse, inequilateral, smooth, thickish, somewhat * Add likewise the U. Curtpreni.—G@ray. oO 194 TESTACEOUS MOLLUSCA. prominent, with fine undulations at the tip; ligament shortish : cuticle yellow, anteriorly with linear green rays, nacre purple and irridescent ; cardinal teeth small, the lateral small and straightish. 1. .13.—-Tennessee. U. Lrenosus. Conr. in Sil. J. 25. t. 1. f. 4.—Con. Mon. U. t. 49. f. 1. Narrow-elliptical, ventricose, posteriorly thick short and rounded, anteriorly abruptly rounded at the ventral edge (which is little curved and entire) and subangulated at the end : beaks approximate, little elevated and corrugated ; concentric lines coarse and prominent; cuticle very dark olive, and obscurely rayed, nacre from bluish white to deep salmon or purple: cardinal teeth oblique, rather compressed and double in both valves. 24.—R. Alabama. U. Osscurus. Lea.on U. 2. (and Tr. Am. 6.)p.7.t. 3.f. 7. Elliptical, transverse, inequilateral subinflated, thickish, ventral mar- gin and anterior dorsal edge straightish ; beaks irregularly undulated : cuticle yellowish brown, with lmear darker rays anteriorly, nacre purple and white: cardinal teeth elevated, the lateral larger near their termination. 151,..2.— Tennessee. _ U. Detopontus. Lam.—vU. Lacreotvus. Lea. Tr. Am. 5. t. 8. f. 19. Elliptic, transverse, not thick, subinflated, posteriorly short narrow rounded, angulated anteriorly ; beaks rounded, having short radiating folds, ligament shortish : cuticle dark brown and wrinkled, nacre pearly and milk white; cardinal teeth long and double in both valves, the lateral long and separate. 2..31.—La Plata. U. Lamexuatus. Lea. on U.2. (and Tr. Am.6.) p. 19. t. 6. f. 16. Subovate, transverse, subinflated, glossy, very thin, dorsal edge straightish, angular at its extremities ; posteriorly much nar- rower and the ventral margin oblique and rounded : umbonal slope with two capillary subparallel raised lines : beaks scarcely prominent, minutely undulated : cuticle dark brown and rayless, nacre bluish : cardinal teeth long, thin, and lamellar, the lateral long thin and nearly straight. 13. .23.—Bengal. U. Bencatensis. Lea. on U. 2. (and Tr. Am.6.) p. 3. t. 2. f. 3. Elliptical, transverse, inequilateral, rather inflated, very thin, dorsal edge angular at both ends, ventral edge subincurved: beaks minutely undulated ; cuticle reddish brown, obscurely rayed : nacre purple: cardinal teeth thin and lamellar, the lateral rather long and linear. 1-3,.. 24.—Bengal. U. Caruxeus. Lea. on U.1.p. 105. (and Tr. Am. Ph. 4.) t. 13. f 25.— Benson. Narrow elliptical, transverse, inequilateral, subcylindraceous, thin, ventral margin centrally straightish, dorsal edge anteriorly straight; beaks rather elevated, rounded, and undu- lated ; cuticle finely wrinkled and bluish green particularly anteriorly, rays very indistinct ; anterior slope with small undulations, and two irregular rays; nacre bluish white, pearly and irridescent: cardinal TRIBE NAYADES. 195 teeth lamelliform and double in the right valve only, the lateral straight. 4..13.—R. Hoogly, Hindostan. U. Oxivarius. Lea. on U. 1. p.118. (and Tr. Am. Ph. 4.) t. 16. f. 38.—Benson. Ovate-oblong, transverse, inequilateral, very thin, pellucid, smooth, anteriorly subattenuated, ventral edge somewhat rounded; beaks slightly elevated, rounded, not undulated ; ligament very small, cuticle olive, very smooth, rays obscure, nacre white and pearly : cardinal teeth large erect and lamelliform, lateral short and lamelliform. +..1}.—India. U. Batavus. Lam. 33.—Schret. Fluss. t. 3. f. 5.—. t. 248. f. 3. Ovate, tumid, shaded off from green to yellow, rayed, posterior side very short; anterior obliquely curved, the extremity rounded. R. Seine, §'c.—Thicher and more obtuse at the extre- mities than Pictorum.+ U. Cumspertannianus. Lea. on U.2. (and Tr. Am. 6.) p. 25. t.7.f. 19. Elliptical, transverse, inequilateral, thin, ventral edge rounded ; beaks somewhat prominent, ligament short ; cuticle yellow with numerous subequidistant narrow greenish rays, nacre white and irridescent: cardinal teeth small, lateral long and straight. #..13$.—Tennessee.* U. Visex. Conr. N. F. W.S.31.¢.4.f. 3. Elliptical, ven- tricose, thinnish, anteriorly dilated, very oblique and arcuated, posteriorly rounded but angulated on the dorsal edge: ligament margin slightly elevated, umbonal slope rounded : cuticle yellowish olive, clouded with brown, anteriorly with green interrupted linear 1 Mr. Lea in his synopsis of Uniones, (a work whose outlines are but filled up in the present monograph), gives as synonyms of this deceptive species. «‘U. Batavus of Fleming, Pfeiffer, Wood, Maton, Dilwyn, Turton—Pictorum of Montagu and of Draparnand, ¢. 11. f. 3.— U. Riparia and Gibba of Pfeiffer.—U. Sinuatus and Planus of Studer.—U. Fusculus of Muhl.—U. Reniformis, Schmidt.—U. De- curvatus, Rossmasler.—U. Fuscus, Consentaneus and Amnicus Zieg.” —I am afraid that Mr. Lea is scarcely correct in his ideas of our European Uniones. Assuredly the above synonyms seem to me so strangely united, that I have not ventured to add one iota to the brief description and scanty references of Lamarck. As this shell has been generally considered British, from trusting to the figures in Wood and Turton, it may be as well to observe, that I have reason to believe that the former was copied from Schreeter’s Fluss- conchylien, ¢. 3. f. 4. (and not from a British shell), whilst the latter is stated by Mr. Gray, to have been delineated from the former. 2 Add likewise the U. Smirnu.— Gray. OFZ 196 TESTACEOUS MOLLUSCA. rays; nacre bluish white, anteriorly irridescent: cardinal teeth direct, prominent, pyramidal. 2.—R. Alabama. U. Muutretpianus. Lea. Tr. Am. 6. f. 36. p. 41. Elliptical, rather compressed, transverse, inequilateral, thickish, rounded at both ends, ventral and anterior dorsal edge straightish : beaks rather prominent, finely undulated : cuticle yellowish with dark green rays anteriorly, nacre white and irridescent ; cardinal teeth rather small and erect, lateral long and erect. 1-3, . . 2-3,.— Tennessee. U. Cresserus. Lea. on U. 2. (and Tr. Am. 6.) p. 33. t. 10. J. 28. Subelliptical, very transverse, very inequilateral, thickish, ventral edge little rounded and rather sinuated, anterior dorsal edge straightish, anterior edge incurved ; beaks rather prominent and undulated at the tip, retuse: cuticle dark green, obscurely rayed : cardinal teeth small and elevated, the lateral obscure ; nacre white. 12..2,%.—Tennessee. U. Grazer. Lea. on U. 2. (and Tr. Am. 6.) 34. t. p. 10. f. 29. LHiliptical, transverse, compressed, smooth and shining, inequi- lateral, thin; beaks somewhat prominent, with fine nearly parallel undulations at the tip ; ligament short: cuticle smooth yellow with numerous fine rays over nearly the whole disc: cardinal teeth small and elevated, the lateral long. +. .14.—Tennessee. U. Hiupretraianus. Lea. Trans. Am. Ph. 5.t. 3. f. 8.— U. Ampigua? Say. Narrow elliptical, subcylindraceous, very transverse, thin, rounded at both ends, ventral edge little arcuated, incurved, subparallel to the dorsal, cuticle dark brown, nacre above brown, below white ; ligament long and thin ; cardinal teeth single in each valve, no lateral. ,.. 13.—Ohio. U. Faspauis. Lea. on. U.1. p. 96. (and Tr. Am. Ph. 4.) t. 10. f. 16.—U. Capitius. Say. Transylv. Jour.—Lariiuvs. Say. Am. Conch. t. 41. Subelliptical, transverse, inequilateral, thick, rounded at both ends ; ventral margin incurved in the middle ; ligament short ; beaks slightly prominent ; cuticle dark, with green hair-like undulating rays (especially anteriorly) ; nacre pearly white and irridescent ; cardinal teeth small, the lateral short thick and enlarged anteriorly. 2..1.— Ohio. U. Parvus. Barnes. Sil. J.6.—Haton.—Conr. Mon. U. t. 6. f. 1. Oblong-ovate, convex, rounded at the sides, thinnish ; beaks slightly elevated and placed at one-fourth the distance from the posterior end ; ligament very narrow, and slope distinct and obsoletely ribbed; ventral edge little rounded ; cuticle brownish, an obtuse slightly elevated anterior ridge; nacre pearly white and irridescent ; the lateral tooth rectilinear, rounded at the end and parallel to the base. 3..11.—Fox River, North America. U. Girans. Lea. on U. 1. p. 92. (and Tr. Am. Ph. 4.) t. 8. J. 12. Ovate elliptical, transverse, inequilateral, inflated, rather thick, rounded at both ends; ventral edge rounded ; beaks some- TRIBE NAYADES. 197 what prominent ; ligament small; cuticle black or dark brown (sometimes rayed), nacre purple ; cardinal teeth rather large and elevated, lateral straight and lamelliform. +.. 1,3, —Ohio. U. Drvaricatus. Lea. Trans. Am. Ph. 5. t. 9. f. 24. Transversely elliptic, rather compressed, thin, ligamental edge straight and parallel.to the ventral edge ; beaks with beautiful divaricating folds ; figament rather short and slender ; cuticle greenish smooth, nacre white and irridescent ; cardinal teeth small, compressed, the lateral long and rather thin. 2, .. 12.—Egypt. U. Fasa. D’ Orbig. Mag.de Z. 1835. Ovate-oblong, com- pressed, thin, smooth, greenish brown, anteriorly subangulated and broad, posteriorly short and rounded; beaks radiated or smooth ; nacre bluish white; cardinal tooth thin, lamellar bifid, the lateral elongated and thin. %..14.—S. America. U. Burrovenranus. Lea. Trans. Am. Ph. 5. t. 10. f. 27. —D’Orb. in Mag. de Z. Obovate, transverse, compressed, thick- ish, anteriorly subbiangular and longer, posterior end dorsally sub- angulate, obliquely rounded below ; beaks with oblique folds and rather prominent ; cuticle smooth, dark brown with yellow lines of growth : nacre pearly white and irridescent ; cardinal teeth large elevated and lamelliform, the lateral nearly straight. 14..22— R.°Parana. S. America. U. Discus.* Lea.on U. 2.(Tr. Am. 6.) t. 18. f. 57. Ellipti- cal, very much compressed, inequilateral, thick, posteriorly rounded, anteriorly much attenuated and biangular; beaks prominent, liga- ment long and thick ; cuticle blackish, nacre purple and irridescent ; cardinal teeth large, the lateral long and separate. —India. U. Simus. Lea. on. U. 2. (and Tr. Am. 6.) p. 26. t. 8. f. 20. -Gvate, transverse, compressed, inequilateral, obliquely angulated anteriorly, ventral edge not much rounded, thickish, beaks somewhat prominent, ligament shortish ; cuticle yellowish and indistinctly rayed, nacre white and irridescent ; cardinal teeth small, lateral long and thick. 1.. 11;.—Tennessee. U. Corrveatus. Lam. 34.—Mya C. Muller.— Gimel. 3221. —D. p. 52.—Ch. f. 22.—W. t. 2. f.31.—Mya Rueosa. Gimel. 3222.—D. p. 53.—Ch. f.1649.—M. Novosa ? Gmel.—Srurtra? Gmel.—U. Spurta. Lam. (fide Lea.) Ovate-rhombic, thin, green, the umbones with angularly flexuous sublongitudinal wrin- kles. 13.— Coromandel. U. Nitoricus. Cail. voy. d Meroe. 2. t. 61. f. 8, 9.—Desh. 1 T may not venture to differ from such an authority as Mr. Lea, but as the figures of Gmelin’s Mya Rugosa (W. ¢. 2. f. 33.) and Nodosa (W. ¢. 2. f. 34.) differ in many particulars from Corrugata, I have given copies of them. 198 TESTACEOUS MOLLUSCA. in Lam. 6. p.552. Ovate oblong, transverse, subdepressed, pos- teriorly obtuse, anteriorly obscurely angulated, striated, dark olive, nacre rosy ; cardinal teeth very salient and compressed in one valve, in the other short and bifid. Senegal and the Nile. U. Eeypriacus. Cail. voy. a Meroe. 2. t. 61. f. 6, 7.— Desh. in Lam. 6. p. 353. Oval-oblong, turgid, subinequilateral, thin, anteriorly broad and dilated ; cuticle olive rayed with yellow, nacre pink and irridescent ; hinge almost linear, with two teeth, the anterior lamella very narrow and acute. Egypt and Senegal. +t + ¢ Oblong. U. Brevipvens. Lea. in Am. Ph. Tr. 4. (1837.) p.75. t. 6. f. 6. Oval-oblong, subtriangular, transverse, thick, inequilateral, umbonal slope curved; beaks slightly prominent, ligament short, ventral edge subincurved in the middle; cuticle yellow and wrin- kled, rays small slightly curved and interrupted ; nacre pearly white, cardinal tooth rather small, slightly elevated and rather cleft in one valve, simple and emerging from a pit in the other, lateral teeth short and thick. 14.. 1,4.—Ohio. U. Terratasmus. Say. Am. Con. t. 23. Transversely oblong- elliptic, thinnish, convex, hinge margin parallel to the ventral and subrectilinear ; posteriorly very short and rounded, anteriorly slop- ing obliquely from the hinge margin to the rounded extremity ; anterior slope with two impressed lines ; beaks little elevated, de- corticated, umbonal slope not prominent : inside white, irridescent anteriorly and on the margin ; lateral teeth two in each valve. 33.— New Orleans. U. Campropon. Say. Am. C. t.42.—Dectuivis. Conr. (fide Lea.) Transversely oblong-oval, moderately thin, a little coni- pressed, not very inequilateral, blackish or dark brownish, dorsal _ line sinuated, obtusely angulated at each extremity ; the ventral edge incurved in the middle, and rounded at each extremity: anterior slope somewhat compressed, with two distinct compressed lines ; um- bonal slope not elevated above the level of the disc ; beaks with small undulations, little prominent ; within milk white, a single rather long oblique undivided primary tooth in each valve, the lateralteeth rather slender towards the tip, alittle arcuated. 2. .3}. — New Orleans. U. Opzsus. Lea. on U. 1. p.106.(andTr. Am. Ph. 4.) t. 13. f. 26. | Ovate-rhomboidal, oblique, inequilateral, inflated, thickish, angular anteriorly, ventral edge little rounded; beaks rather pro- minent, ligament long and large ; cuticle fuscous and much wrinkled, nacre livid white; cardinal teeth elevated and crested, lateral long and curved. 2. .353,.— Virginia. U. Horeronensis. Lea. on U. 2. (Tr. Am. 6.) p. 29. t. 9. f. 24. Suboblong, transverse, inequilateral, compressed, biangular TRIBE NAYADES. 199 anteriorly ; anterior dorsal edge rather elevated, thickish, flattened at the umbones and sides, carinated ; beaks little prominent, undu- lated at the tip; ligament thin long and straight ; cuticle dark brown, obscurely rayed, nacre purple and irridescent ; “cardinal teeth small, thick ; the lateral long and curved. 1,35. 33. — Near Darien. U. Roanoaxensis. Lea. on U. 2. (Tr. “Am. 6. ) p27: t. 8: f. 21. Oblong, transverse, inequilateral, biangular anteriorly, com- pressed, thick, ventral and dorsal edges little rounded, flattened on the umbonal slope; ligament very large and long: cuticle dark brown (apparently) rayless, nacre white ; cardinal teeth small, the lateral long and slightly curved. 21..4,%4.—N. Carolina. U. Jesunus. Lea. on U. 2. (Tr. Am.6.) p.9.t. 4. f. 9. Oblong, transverse, compressed, thinnish, inequilateral, flattened on the sides, rounded posteriorly, subbiangular anteriorly ; ventral edge little rounded, incurved in the middle: beaks compressed, scarcely prominent ; ligament thin and long: cuticle very dark brown and much wrinkled, nacre “purple or white; cardinal teeth small, the lateral long and straight. 14..24.—Roanoke. U. Compxtanatus. Lea. on U. 1. p. 62.—Mya C. D. p. 51. —U. Purpursus. Say § Barnes.—vU. Rarisutcata. Lam.— U. Coarctata. Lam.—U. Purpurascens. Lam.—U. Ruom- BuLA. Lam.—U. Carinirera. Lam.—vU. Groreina. Lam.— U. Guasrata. Lam.—Svuucipens. Lam. Oblong ovate, some- times subrhomboidal or suboval, anteriorly broader and much longer more or less angular, posteriorly rounded, ventral edge little rounded an obtuse ridge from beaks anteriorly, surface with coarse wrinkles of growth, the cuticle tar-coloured or very dark green : nacre dark peach (at times salmon to violet pearl) cardinal teeth deeply striated, pyramidal. 2..33.—Massachussets. U. Grirriraranus. Lea. Trans. Am. Ph. 5.t.15.f. 46. Trans- versely elongated-elliptic, thickish, spread out, somewhat flattened on the sides, rounded on the umbonal slope, ventral edge little arcuated, inequilateral, beaks small and scarcely elevated; cuticle yellowish with green rays, nacre purple salmon or white : igs teeth compressed, the lateral long and curved. 13..28,.— Florida. U. Arratus. Lea.—Nara A. Swain.—vU. Fraciuis. Swain. in Z. Il. \st ser. Transversely oval, rounded above and below at both extremities, thin, ventral and dorsal edge arcuated, the former not all incurved: moderately convex, smooth, the cuticle varying from black to olive green, nacre purplish near the umbones : in one valve two short obtuse and nearly obsolete cardinal teeth, a single rather sharper one in the other. 2..3.—N. America.—Liga- 1 Add likewise the Nara Aurata of Swainson. 200 TESTACEOUS MOLLUSCA. mental edge in the young, nearly straight and subangulated at the extremities. U. Conrertus. Lea. Trans. Am. Ph. 5.t.16.f.47. Trape- zoidal, transverse, inequilateral, inflated, thickish ; beaks slightly elevated and transversely wrinkled, umbones much swollen, liga- ment rather short and thin; cuticle dark brown, shining, nacre purple or salmon; cardinal teeth compressed and double in both valves, the lateral long and curved. 1 3,..2%.—S. Carolina.) U. Funvus. Lea. Tr. Am. Ph. 5. t. 13. f. 39. Icrerinus. Con. Narrow elliptical, transverse, inequilateral thinnish, subin- flated, rounded posteriorly, angulated anteriorly, ventral edge entire, dorsal straight, umbonal slope rounded, beaks slightly elevated ; cuticle yellow and yellowish brown, nacre salmon: cardinal teeth oblique, the lateral somewhat curved. -9,..13.—S. Carolina. U. Conaarmus. Lea. on U.1. p. 82.(and Tr. Am. Ph. 4.) t. 6. f. 4. Elliptico-rhomboidal, transverse, inequilateral, thin, somewhat flattened at the sides, anteriorly slightly sinuated, the slope and beaks with slight undulations ; ventral edge little rounded; ligament short: cuticle yellow and yellowish brown, with numerous green rays: nacre satinlike and irridescent : cardinal tooth oblique and compressed, the lateral long and enlarged anteriorly. 1..13— S. Carolina. U. Decuivis. Say. Am. C. t. 35.—U. Geomerricus. Say. Transverse, thickish, posteriorly short and rounded, ligamental edge rectilinear very slightly (af at all) elevated and forming a sharp angle with the anterior edge which runs down obliquely to the entire and but slightly rounded ventral edge : umbonal slope not elevated ; surface deeply wrinkled: inside just tinged with pur- plish ; cardinal teeth oblique, the lateral distant, rectilinear, oblique. 21.—N. America. U. Buanpineianus. Lea. Tr. Am. Ph. 5, t. 15. f. 44. Sub- trapezoidal, transverse, very inequilateral, thin: beaks somewhat prominent : cuticle fuscous, wrinkled, nacre dull purple: cardinal teeth compressed, the lateral long and curved. 13. . 23;.—lorida. U. Depressus. Lam. 38.—D’ Orb.—Lesson. voy. de Coq. t. 15. f. 55? Ovate-oblong, depressed, thin, roundedat the extremi- ties of the sides : cuticle brown, nacre bluish. 2.—New Holland. U. Aneustus. Lam. 42.—an Lust. t. 147. f. 3. Transversely oblong, narrow, subsinuated, anteriorly with two obsolete angles, extremities of the sides rounded; cuticle yellowish brown, slightly striated longitudinally on the depression in the middle. 22.° id Add likewise the U. Paxiatus of Ravenel’s letter, and the U. Warerensis of Lea, the Ravenjli of Conrad. 2 Add likewise the U. Moprsrus of Ferussac. TRIBE NAYADES. 201 U. Lirrrorauis. Zam. 25.—Crassus. Schr. F. 2. f. 2.— RuomsBorpEA. Schr. 2. f. 3.—BReviatis, SeEMIRUGATA, and Nana. Lam. 14, 16, § 17. (fide Lea).—Incurvus. Lea. on U. 1. p. 167. t. 13. f. 27. Transverse, oval, thick, dark brown, inequilateral, transversely striated, posteriorly rounded, anteriorly produced, ligamental edge sloping, ventral edge little arcuated, sub- incurved: anterior slope with a marginal groove on each side: beaks wrinkled: cardinal teeth thick, conical, dentato-serrated, the lateral thick. 23.—France, §c. t++tt+ Subrotund. U. Crrcuxus. Lea. Tr. Am. Ph. 3. t. 9. f. 14.—Hat.—Mya Rotunpa ?’—Wood. Circular, ventricose, subequilateral, thick, transversely wrinkled ; beaks rather elevated and somewhat re- curved; ligament short and thick ; cuticle dark brown becoming light yellowish brown anteriorly, shining and satinlike, nacre pearly white and irridescent : teeth large. Diameter, 13.— Ohio, §c. U. Lens. Lea. on U.1. p.90. (andTr. Am. Ph. 4.) t. 8. f.10. Lenticular, broader than long, subventricose, equilateral, thickish, beaks slightly prominent, undulated at the tip, igament short and thick: cuticle smooth brown but anteriorly yellowish, nacre white rarely rosy y cardinal teeth large, the lateral short and straightish. 2, .. 14.— Ohio. "°U. Rusetuus. Conr. N. F. W. S. Ds 8, t+ Oa fe Ant. SDE orbicular, transverse, ventricose, thick, subequilateral, umbones prominent, umbonal slope rounded, margined before and behind by a faint angle; beaks eroded, slightly prominent ;_ cuticle reddish brown, nacre pink or purplish: cardinal teeth direct.— R. Alabama. U. Masoni. Conr. N. F. W.S. p. 34. t. 5.f.2.—Con. Mon. U. t. 12. f. 2. Transverse, suborbicular, discs slightly flattened ; umbones broad prominent, carinated behind : beaks slightly promi- nent : umbonal slope straight and angulated, ligament slope flat- tened and broad: cuticle olive, clouded with brown and polished, nacre bluish white: cardinal teeth prominent, compressed very oblique: 3.—2. Savannah, N. America. U. Rorunpatus. Zam.—Susorsicuuata. Lam. & Bl.— U. Gresutus. Say. Am. Conch. t. 34.—Susceiososus. Lea. Tr. Am. Ph. 5. t.2. f.3. Transverse, obovate, inflated, thick, pos- teriorly rounded and shorter, anteriorly subangulated, ventral edge arcuated and somewhat sinuated anteriorly ; beaks slightly promi- nent, rounded; umbonal slope carinate, ligament thick and shortish: cuticle dark brown or black, nacre pearly pink ; cardinal teeth wide and striated, the lateral somewhat curved. 2,;)..1;%.— Louisiana. 202 TESTACEOUS MOLLUSCA. U. Paranensis. Lea. Tr. Am. Ph. 5. t. 14. f.42.—U. Sox- s1ana.—D?’ Orb. in Mag. de Z. Subrotund, inequilateral, com- pressed, thickish, umbonal slope flattened; beaks rather elevated, longitudinally folded and retuse, ligament thin ; cuticle wrinkled, shining, greenish becoming brown towards the margin, with very obscure curved rays which sweep from the beak towards the pos- terior side, nacre pearly white and irridescent: cardinal teeth recurved, double in both valves, the lateral rather long and curved. 3..33.—&. Parana. U. Memsranacea. Lea.—Mytitus M. Maton.—Lin. Tr. 10. ¢. 24. f. 11, 12.—U. Matonrana. D’ Orbig. 8. Am. t. 71. f- 1, 2. Roundish, subinflated, posteriorly shorter and rounded, anteriorly angulated, dorsal edge straight, very thin, smoothish, greenish rufous, with very small ribs diverging from the beaks, inside bluish or pink : cardinal tooth thin straight and solitary, the lateral tooth anteriorly very long and elevated. 2..22.—S. America. U. Variasiuis. Lea.—Mya V. Maton in Lin. Trans. 10. t. 24. f. 4, 5,6, 7.—W. t. 3. f. 38.—D. p. 53.—U. Rorunpvus. Wagn. in Spix. Braz. t. 26. f. 3, 4. Subrhombic gibbous, the um- bones longitudinally wrinkled ; transversely striated, the wrinkles gradually disappearing, cuticle greenish brown, dorsal edge nearly straight, and subangulated at its extremities, ventral edge poste- riorly very obliquely rounded ; nacre bluish: hinge with two teeth diverging at the apex and inserted in linear receptacles. 1..1— S. America. U. Personatus. Say.—U. Capituaris. Lea. Trans. Am. Ph. 5. t. 2. f. 2. Obtusely subquadrate, broader than long, ven- tricose, thickish, subangular and longer anteriorly: beaks thick and elevated, ligament short and thick; cuticle dark and finely wrinkled, smoother towards the beaks, rays numerous capillary and spread- ing, nacre pearly white and irridescent: cardinal teeth much elevated, the lateral lamellar and inclined to curve upwards. 1}..1,%,.— Ohio. U. Retusus. Lam.—Conr. Mon. U.t. 8.—Torsa. Raf. in Ann. de Sc. Phy. 5. t. 82. f.1, 2, 3.—Haton. Obtusely sub- triangular, ventricose, with concentric furrows : beaks subcentral, retuse, umbo very prominent and leaning posteriorly ; ligament long and prominent; umbonal slope rounded and undefined ; pos- terior and ventral edges regularly rounded; anterior side with a slight furrow ; ligamental edge curved and very oblique : within dark purple margined with white: cuticle olive. 24. .2— N. America. U. Esrenus. Lea. Tr. Am. Ph. 4. t.9. f. 14.—Mytizoripes. Conr. (not Raf.) Obliquely obovate, inequilateral, very ventricose, very thick; beaks nearly terminal and much elevated, ligament TRIBE NAYADES. 203 rather short and thick: cuticle blackish brown before the beaks and at their tip, on the second growth yellow, nacre pearly white: cardinal teeth large, lateral large and curved. 13 ..13.—Ohio. U. Macuzatus. Conr. N. F. W. 8S. p.30.t. 4. f. 4. Sub- triangular, compressed, thickish ; cuticle much wrinkled except on the smooth umbones, brown olive with a few very broad and narrow intervening interrupted green rays; a slight broad and oblique furrow from the prominent beaks to the base: umbonal slope sub- angulated, behind which the shell is cuneiform, ligament edge ob- lique, rectilinear, anterior edge obliquely subtruncated : cardinal teeth nearly transverse, subcompressed: nacre very white and irri- descent.— Tennessee. U. Kirxyvanpianus. Lea. Trans. Am. Ph. 5. t. 14. f. 41. Rounded-subquadrate, broader than long, thick, compressed, ante- rior and ligamental edges little arcuated ; beaks somewhat elevated, ligament thick and rather short; cuticle wrinkled, dark brown but yellowish near the beaks, with interrupted rays not reaching the well rounded ventral edge, nacre pearly white and irridescent : cardinal teeth thickish, the lateral short and slightly curved. Diets 2-3,.— Ohio. U. Susrorunnus. Lea. Tr. Am. Ph. 4. t. 18. f. 45.—Pott- tus? Say.—Suborbicular, subventricose, thick, subequilateral, beaks thick and elevated, ligament thick and shortish; cuticle yellow and smooth towards the beaks, becoming brown and finely wrinkled towards the margin, with interrupted rays about the umbones, nacre white and. irridescent: cardinal teeth thick, the -lateral short and slightly curved. Diameter, 12.—OQhio. U. Inrucatus. Conr. F. N. W.S. p. 45. t. 3. f. 2. Trans- versely obovate, compressed ; anteriorly dilated, the margins slightly oblique, obtusely rounded or subangulated at its extremity; umbones wide, not prominent, beaks greatly eroded; umbonal slope subangulated and hardly curved: cuticle black, nacre pearly white: cardinal teeth direct, pyramidal.—G'eorgia in America. U. Coccinreus. Lea. on U. 2. (and Tr. Am. 6.) p. 12. t. 5. Jf. 12.—Conr. Mon. U. t. 13. f. 1.—Catitius. Conr. Mon. U. t.13.f. 2. Subtriangular, oblique and slightly compressed, thicker posteriorly, posterior dorsal edge very short and sharply angulated ; beaks rather elevated retuse, with one or two undulations; liga- ment rather Jong and curved: cuticle dark reddish brown, nacre bright red: cardinal teeth thick, the lateral thick and somewhat curved. 2..21,—Ohio. tttttt+ Wide. U. SuHeparpianus. Lea. Trans. Am. Ph. 5. t. 13. f. 38.— Very elongated transversely, thickish, short and rounded poste- 204 TESTACEOUS MOLLUSCA. riorly, produced and subcuneiform anteriorly, ligamental edge straightish, ventral strongly incurved, sides and umbones flattened; umbonal slope elevated, beaks small, ligament thin and long; cuti- cle blackish brown, (sometimes with obsolete rays), nacre purple and irridescent : cardinal teeth oblique, single in one valve, double in the other, the lateral very long and straight. 12..5.—Georgia, N. America. U. Fotuicunatus. Lea. on U. 2. p. 38. (and Tr. Am. 6.) t. 11. f. 33. Transversely elongated, very narrow, rather thin, very inequilateral, rather compressed, flattened at the sides, rounded posteriorly, subbiangular anteriorly, ventral edge slightly incurved in the middle ; beaks scarcely prominent ; cuticle very dark brown, nacre purple and irridescent: cardinal teeth small, the lateral long and somewhat curved. +..22.—R. Savannah. U. Recrus. Lam.—Pratonevus. Barnes in Sil. J. 6.— Hild—Mya Pratonea. Wood. S. f. 11. Much elongated transversely, narrow, thick, tumid, the beaks flat, rounded at both ends, but anteriorly attenuated and produced, posteriorly short, ventral edge little rounded (incurved in the old): cuticle blackish brown with fine interrupted wrinkles in longitudinal rows, (in the young smooth glabrous and rayed with yellowish olive) : nacre purplish, the lateral tooth long and thin. 275...6%.—N. Ame- rica. U. Deniscens. Say. Am. Con. t. 24.—OriEns. Lea. on U.1. p. 83. (and Tr. Am. Ph. 4.) t. 6. f. 5. Elongated oblong, transverse inequilateral, compressed, very thin, anteriorly attenuated, ventrally not incurved, little rounded; beaks scarcely prominent and retuse, ligament linear: cuticle yellowish with oblique inter- rupted green rays, nacre bluish white and irridescent, purple under the beaks: cardinal teeth small and imperfect, lateral undivided and imperfect. 151,..24.—Ohio. U. Aneustatus. Lea. on U. 1. p. 124. (and Tr. Am. Ph.4.) t.17. f. 43. Transversely elongated oblong, angulated anteriorly and its dorsal edge straightish, the ventral incurved in the middle ; thin rather compressed, the beaks slightly elevated and undulated at the tips; cuticle reddish brown with the rays obsolete, nacre dull purple: cardinal teeth elevated and compressed, lateral long and nearly straight. 1,1, .. 24.— 8. Carolina. U. Lanceoxatus. Lea. Tr. Am. Ph.3.t. 3. f. 2. Trans- versely elongated, compressed, attenuated and subangular anteriorly, thin, ventral edge not incurved, beaks scarcely prominent; cuticle . lemon or olive yellow and glabrous, nacre salmon colour and irrides- cent : cardinal tooth sharp and oblique. 7%,.. 144.—Tarborough. U. Anopvontorpes. Lea. on U. 1. p. 91. (and Tr. Am. Ph. 4.) t. 8. f. 11.—U. Teres. Conr. Narrow elliptical, transverse, inequi- lateral, inflated, thickish, posteriorly rounded, anteriorly subat- Li / TRIBE NAYADES. 205 tenuated ; beaks slightly prominent, ligament long narrow and nearly straight : cuticle yellowish, very smooth and shining, anterior slope fuscous, nacre pale salmon or white ; cardinal teeth double in both valves and very erect; the lateral long, slightly curved and separate. 1-9,.. 4;15.—Missisippi. U. ParatteLoripepon. Lea. Trans. Am. Ph. 5. t. 8. f. 20.— D Orb. in Mag. de Z. Oblong, transverse, subcylindraceous, thickish, dorsal and ventral edges parallel, posteriorly short and obtuse, anteriorly inflated and obliquely angulated dorsally ; liga- ment long and thin, umbones flattened, umbonal slope carinated ; beaks somewhat elevated, retuse ; cuticle wrinkled and almost black, nacre pearly white andirridescent ; cardinal teeth oblique, crested, the lateral long and straight. 11..27,.—. Parana, South America. U. Pruatyrruincuus. Rossm. f.130. Transverse, elongated, wedge-shaped, inequilateral, anteriorly produced in a compressed beak which points downwards, ligamental edge very long, very short and rounded posteriorly : the umbones tumid; olive with brown zones : cardinal teeth very compressed, bladed. 3.—Germany.1 U. Tumipus. Retz.*—Rossm.-f. 70, 202, 3, 4.—Mya Ovara. Don. t. 122.--D. p. 50.—W. t. 2. f. 27.—Mysca Sozrpa. Turt. B.t. 16. f. 2.§ Man. f.13.—(U. Noputosa. Lam. fide Lea.) Transverse, inequilateral, ovate, elongated, the anterior side wedge- shaped tumid produced and attenuated, thick, brown, ventral edge arcuated ; umbones prominent and rugose; posterior teeth thick, high, triangular, strong, left anterior strong: nacre white, (rarely pale salmon,) the young with irregular concentric nodulose ridges roundthe umbones. Germany, §c. U. Picrorum.* Lam. 32.—Drap. t.11.f.4.—Mya P. Lin. 1112. D. p. 49.—W. t. 2. f. 26.—Mysca P. Turt. Man. f. 11.— U. Rosrrata. Lam.31.—U. Manca. Lam. 43.—U. Turrontr. Payraud.— CarierioLto. Payr.— Evoneatura. Pfeif. t. 8. f. 5,6. Oval-oblong, ventricose, anteriorly produced into a bluntly truncated beak, yellowish green, brownish zoned, greenish anteriorly, dorsal edge nearly straight, ventral rather retuse ; hinge teeth very much compressed, arched and crenated, anterior teeth of the left valve small or evanescent ; nacre white. 3.—Hurope. U. Evoneatus. Pfeif.* U. Propuctts. Conr. Mon. U.t. 14. f. 1. p. 31. Narrow- elliptical, rather compressed, posteriorly very short and rounded (the hinge subterminal,) anteriorly produced and obtusely acuminated 1 Add likewise the U. Cariuaunpi of Ferussac. 2 I find no species of this name in Pfeiffer. His ELonGATuLUs (fide Gray, ) is but a variety of Prcrorum. 206 TESTACEOUS MOLLUSCA. ligamental edge parallel to the line of the ventral which is scarcely arcuated and subincurved in the middle ; ridges of the umbonal slope obtuse, beaks not raised abovethe dorsal line : cuticle brown ; inside purplish ; teeth thick, the cardinal direct. 1..21.—R. Savannah, N. America. U. Nasutus. Say. En. Am. Nic.—Barnes.—Swain. Zool. Il. - Ist Ser.—Lis. t. 151. f. 6.—Mya Nasuta. Wood. S. t. 1. f. 4. Elongated-oblong, transverse, posteriorly short and rounded, an- teriorly very produced and obtusely acuminated ; ligamental edge straight: thin, compressed, horn-coloured brown or olive (some- times obscurely rayed with green) nacre bluish white: teeth crenated. 2}! ..23.— Delaware. U. Fisnerianus. Lea. Tr. Am. 6. t. 4. f. 8. Transversely elongated, acutely angular anteriorly, very short and rounded pos- teriorly, ventral edge not incurved, compressed and thin ; beaks and umbones flattened, ligament thin and short : cuticle dark brown and smooth: nacre purple; cardinal teeth lamellar, the lateral long and somewhat curved. 1,1,.. 275.—R. Chester, North America. U. Javensis. Lea. on U. 2. (and Tr. Am. 6.) p. 28. #. 9. f. 23. Narrow-elliptical, transverse, very inequilateral, anteriorly subangular, thin, subcarinate, ventral edge little rounded, beaks somewhat prominent, ligament rather long; cuticle brown and (apparently) rayless, nacre purple ; cardinal teeth compressed, the lateral long and straight. 14..23.— Florida. U. Lucusris. Lea. (Tr. Am. Ph. 6.) t. 9. f. 25. Elliptical, transverse, somewhat inflated, inequilateral, anteriorly biangular, posteriorly rounded, thickish, ventral edge little rounded, the beaks rather prominent, ligament thin and shortish: cuticle nearly black, (apparently rayless) ; nacre purple; cardinal teeth compressed, lateral longish and somewhat curved. 1-3, .. 24.— Near Darien. U. Marernauis. Lam. 41.— L. t. 247. f.1. Ovate-oblong, transverse, subrhombic, thin, brown with concentric yellow or tawny bands towards the margin; inside bluish, cardinal tooth small. and compressed. 3:—Bengal.1 U. Ints. Lea. Tr. Am. Ph. 3. t. 11. f. 18.—U. Nesutosus. Conr. Narrow elliptical, inequilateral, subventricose, thin, rounded at both ends, beaks slightly prominent : ligament rather long and thin; cuticle yellowish green with numerous narrow rays, nacre bluish white: cardinal teeth double in the left valve, subbifid in the right, small and erect, the lateral long and thin. #..12.—Ohio. U. Tenvissimus. Lea.—-Sympnonora T. Lea. Tr. Am. Ph. 3. t. 11. jf. 21.—Purpurascens. Swain.—U. Vetum. Say. Narrow-elliptical, inequilateral, transversely wrinkled, compressed, oe 1 U. ANopontina. Lam. 47. is the same species, fide Lea. TRIBE NAYADES, 207 very thin and fragile, obliquely rounded posteriorly : the dorsal edge connate and anteriorly rather elevated, ventral edge little rounded and not incurved; beaks depressed, but pointed; ligament con- cealed ; cuticle yellow, finely and obliquely rayed with green, nacre bluish white and purple, irridescent ; cardinal tooth a small lobe, lateral teeth acicular and single in both valves. 24..24.—Ohio. U. Bizineatus. Benson.—Sympuonora. B. Lea. on U. 1. p. 108. (and Tr. Am. Ph. 4.) t. 11. f.19. Subelliptical, trans- verse, inequilateral, compressed, very thin, dorsal edge angulated at both ends and anteriorly elevated and connate; ventral edge rounded and entire; beaks very little elevated, concentrically undulated, with two elevated lines running to the anterior margin ; cuticle glossy greenish yellow and darker on the anterior slope ; nacre slightly sal- mon-coloured ; cardinal teeth lamelliform and double in the right valve only, the lateral straight. 3%, .. 143,.—.R. Hoogly, Hindostan. U. Corritanus. Lea. Trans. Am. Ph. 5. t. 9. f. 25. Narrow elliptical, very transverse, very thin, very inequilateral, dorsal and ventral edges subparallel straightish and entire, obtusely acuminated anteriorly, beaks scarcely prominent, ligament long and slender : cuticle smooth, rayless, dark brown, nacre pearly white and irrides- cent ; cardinal teeth thin and bladed, the lateral long thin and nearly straight. 1 .. 2,45.—India. U. Puaseotus. Hild. in Sil. J. 14. p. 283.—aton. in Transylv. J. of Med. 1831.—U. Pranuuatus. Lea. on U. 1. p. 45. and Tr. Am. Ph. 3. Ovate-elliptical, transverse, mequilateral, rounded at both ends, peculiarly flattened over the umbones, thick ; beaks slightly prominent and decorticated; ligament little pro- minent ; cuticle wrinkled; yellowish brown, marked with square spots disposed in rays, nacre bluish white: cardinal tooth small, the lateral large thick and curved. 1-3, .. 24.— Ohio. U. Arcus. Conr. Sil. J. 25. t. 1. f. 8. Narrow-elliptical, thick, ponderous, transverse, posteriorly short and rounded, ante- riorly produced and attenuated, ventral edge little arcuated and in- curved ; dorsal edge forming an arched curve scarcely interrupted by the beaks ; cuticle olive and wrinkled, nacre pearly white ; car- dinal teeth thick, pyramidal and distant from the lateral. 2.—R. Alabama. North America. U. Arcratus. Conr. Sil. J. 25. t. 1. f. 9. Narrow-ellip- tical, elongated, much compressed, slightly contracted from the depressed beaks to the base, anteriorly much produced and suban- gulated at the end, cuticle very dark olive, nacre bluish white: ven- tral edge incurved in the middle, but little arcuated; cardinal teeth disposed to be single in both valves, the lateral compressed and a little prominent. 2.—R. Alabama. U. Grssosus. Barnes Sil. J. 6. t.11. f.12.—Kat. in Tr. Jour. 1831.—Hild. in Sil. J. 14.—U. Mucronatvus. Barnes.— 208 TESTACEOUS MOLLUSCA. U. Nasuta. Lam.—U. Divatatus. Conr. Transversely elongated, heavy, gibbous, anteriorly rapidly attenuated and produced, pos- teriorly narrow, rounded, ventral edge little rounded ; beaks flat ; cuticle blackish brown finely striated and deeply wrinkled trans- versely, nacre purplish, teeth crenate, the lateral rough, very thick, incurved. 12,.. 4.—N. America. U. Arctior. Lea. on U.2. (and Tr. Am.6.) p. 10. t. 4. f. 10. Narrow elliptical, transverse, obliquely rounded posteriorly, attenuated and subangular anteriorly, flattened on the sides, thin- nish, the beaks compressed and undulated, ligament rather long and slender; cuticle dark brown and wrinkled, nacre white or salmon colour ; cardinal teeth small, the laterallong. Ohio. U. Paraconicus. D’Orb. 8. Am. t.70. f.1.t04. Oblong, compressed, thickish, smooth or strigillated, blackish or yellowish brown ; posteriorly very short and rounded, anteriorly produced and attenuated at the rounded extremity, ligamental edge nearly straight and long, cardinal tooth thick and crenulated, the lateral very elon- gated, inside bluish white or pink. 13..3%.— Patagonia. U. Vaucuanianus. Lea. on U. 2. (and Tr. Am. 6.) p. 5. t.3. f. 5.—Caroxinensis. Rav. Transversely ovate, somewhat inflated, rather thin, enlarged towards the anterior ventral margin, before which it is subincurved, anterior side obtusely aciminated, its dorsal edge nearly straight; beaks scarcely prominent, cuticle blackish, obscurely rayed anteriorly, nacre salmon coloured : cardinal teeth small and erect, the lateral straight. 11..2.—S. Carolina. tttttt tt Obovate. U. Purpuratus. Lam. 6.—Arzr. Lea. on U. (Tr. Am. 3.) t. 7. f-9.—U. Luaupris. Say. Am. C. t. 43.—U. Poutsont. Conr. Transversely ovate, inequilateral, much inflated, much broader and obtusely truncated anteriorly, the ventral edge little rounded, anterior dorsal edge rather elevated; thick, the beaks slightly projecting and decorticated ; cuticle black, wrinkled trans- versely, nacre rose colour; cardinal teeth erect and crestlike, the lateral granulated and straight. 3 ..43.—Missisippi. U. Ruomseus. Wagn. Test. Braz. t. 28. f.1,2. Rounded- ovate, oblique, anteriorly dilated, and narrowed posteriorly, thick, transversely striated or grooved, rounded at both ends, dorsal edge more arcuated than the ventral; beaks depressed and decorticated, cuticle brown, nacre bluish white : cardinal tooth thick, compressed, substriate, bifid. 21,..3.—Brazil. U. Cuprinus. Lea. on U.1. (Tr. Am.4.) t. 12. f. 24.—Me- TALLICUS.—Say. Ovate, transverse, inequilateral, inflated, thin, rounded at both ends, broader anteriorly, the ventral margin little rounded and much incurved in the middle ; the beaks small, pointed, with concentric undulations, ligament long and lanceolate: cuticle TRIBE NAYADES. 209 reddish brown and wrinkled ; cardinal teeth small, lateral thin and lamellar. 1-3, .. 24.—Mewico. U. Mopiouirormis. Lea. Tr. dm. Ph. 5. t. 13. f. 40.— U. Dextumsis. Conr. Elongated-ovate, very thin, inflated, trans- verse, rounded at both ends, very narrow and short posteriorly : dilated anteriorly ; beaks small, ligament rather long and thin; cuticle brown and shining, rays indistinct, nacre slightly purple, very irridescent : cardinal teeth small, compressed, the lateral long and curved. 13..2,1,.—S. Carolina. U. Tenerus. Rave.—Teneprosus. Conr. F. W.S. p. 42. t.7.f.1. Elliptical, ventricose, thickish posteriorly, beaks pro- minent, anteriorly dilated, the edge descending eblique and recti- linear from the ligament, and subtruncated at the extremity, ventral edge simple and little rounded ; cuticle olivaceous with linear rays: the margins dark brown, nacre irridescent bluish or pink, teeth moderately thick.— Virginia. U. Tarpanranus. Lea. on U. 2. p. 62.¢. 17. f. 55. Ovate, rather inflated, inequilateral, thin, anteriorly dilated, ventral margin subincurved, umbonal slope rounded and inflated ; beaks somewhat prominent, with double undulations, ligament slender and shortish; cuticle yellowish brown, with dark rays and the border dark ochre- brown, nacre somewhat salmon-coloured : cardinal teeth compressed and curved, lateral thin. 1515 ..2.—Hollidaysburg. U. Conrrapens. Lea. on U. 2. p. 75. t. 18. f. 58. Ovate, rather inflated, inequilateral, thin, smooth, ventrally and posteriorly rounded, obtusely angulated anteriorly, and the dorsal edge elevated; beaks rather prominent and undulated, ligament thin and longish : cuticle yellowish green becoming green on the anterior slope, nacre white and irridescent: cardinal teeth linear, the double one in the right valve, the lateral thin and somewhat curved. 1-5. . 1-9. U. Srraminevs. Conr. in Sil. J. 25. t. 1. f. 6. Suboval, convex, anteriorly longer, wider and rounded above and below, ven- tral edge incurved in the middle, beaks slightly prominent, with irregular undulations, umbones convex ; concentric lines remarkably coarse and prominent: cuticle straw colour, rayed only on the ante- rior slope, nacre pearly white and irridescent; cardinal teeth double in both valves and subcompressed. 23.—R. Alabama. +t+ttttttt+ Arcuated. U. Crasstssimus. er.—Sinvatra. Lam. 1.—Desh. (not Pfeif. nor Blainv.)—Drap. p. 132. t. 10. f. 17. to 19.—E. t. 248. Jf: 1.—Rossm.f. 195. Ovate-oblong, ponderous, thick, dark brown, breadth about twice the length, very inequilateral, posteriorly rounded, anteriorly obliquely and obtusely subtruncated, ventral edge retuse, dorsal arcuated: cardinal teeth thick, the lateral P XR 210 TESTACEOUS MOLLUSCA. lamelle thick and slightly exserted, ligamental sinus large and oval. 2..4—Rhine, Loire, §c. U. Monopontus. Say. Am. C.t.6 —EKat.in Tr. Jour. Med. 1831.—U. Sotentrormis. Lea. on U.1.p. 97. Elongated, trans- verse, thin, inequilateral, compressed, rounded and sloping from the beaks at both ends, ventral margin strongly incurved in the middle; the beaks slightly prominent : cuticle very dark brown and wrin- kled, the nacre bluish white and irridescent: cardinal tooth a simple small tubercle in both valves, the lateral long straight and very im- perfect. 14, ..443;,— Ohio. U. Emareinatus. Lea. Trans. Am. Ph. 5, t. 9. f. 22. Transversely elongated-oblong, thickish rounded and very short posteriorly, anteriorly obtusely subbiangulated, ligamental edge straightish, the ventral strongly incurved in the middle and com- pressed ; beaks rather elevated and undulated at the tip: ligament long and thin, cuticle greenish yellow, becoming green on the ante- rior slope, nacre pearly white and irridescent: cardinal teeth small oblique and double in both valves, the lateral long and slightly curved. 1,3,..24. Division B. Having one cardinal tooth. Section A.—Plicate. U. Compranata.—Axtasmoponta C. Barnes § Hild.— Sympnonota C. Lea. on U. 1. p. 62. Triangular-ovate, inequi- lateral, transversely wrinkled, compressed, thick; anterior dorsal edge winged connate and obscurely undulated at right angles to the wrinkles: the beaks compressed and scarcely projecting, undulated, the ligament concealed with an oblique callous plane under it: cuti- cle dark brown, nacre white and irridescent : a large cardinal tooth in each valve. 3..5.—Ohio, &c. U. Conrracosa.—ALasmoponTa C. Say. Am. Con. t. 21. Transversely suboval, dark olive or blackish, inequilateral, anterior edge forming an angle with the scarcely sloping ligamental one; convex, with oblique irregular abbreviated undulations not directed towards the beak, and numerous more or less abbreviated, slightly raised lines from the umbo becoming obsolete towards the base, those in front divaricating towards the hinge margin: beak with a groove and a double series of three or four tubercles: inside white margined with opaque whitish or violaceous. 33.—-N. America. U. Arcuta.—Mare. A. Lea. on U. 2. p. 71. t. 22. f. 69. Triangular, very inflated, very thin, with about eight transverse curved folds, dorsal edge much sinuated and angulated posteriorly : ventral edge little rounded and not incurved, the umbones very TRIBE NAYADES. 211 large, the umbonal slope acutely carinate, the anterior slope very much flattened, having an indistinct furrow along the edge of the carina, cuticle dark green, with numerous green rays over the whole surface, nacre bluish: teeth lamellar and irregular.— Georgia im America. U. Marernata.—Mare. M. Lea. Tr. Am. Ph.6.—Varicosa. Lam.—Mya Rucutosa. W. 8. f.7.—Avasmoponta M. Say. in J. A. N. S. Phil. 1.—Barnes in Sil. J. 6.— Gould. Mass. p. 116. f. 77. Transversely ovate, thin, inequilateral, gaping ante- riorly, posteriorly narrow, rounded at both extremities above and below ; ligamental edge scarcely sloping, ventral subincurved in the middle ; umbonal ridge elevated and well defined, anterior slope with coarse rounded wrinkles running oblig’ ely dorsally and ante- riorly, beaks at the posterior third, rather s/ all but elevated : cuti- cle olivaceous, shining, obscurely rayed with broken lines : nacre bluish white, with a chalky white margin ; tooth small, compressed, looking backwards. 1-1; ..2.—Massuchusets, Se. U. Rucosa.—Axasmoponta R. Barnes in Sil. J. 6. t. 13.f. 21.— Eat. § Hild.—U. Aspucta. Say. Oblong, thick, rounded at both ends, posterior side not quite so long nor broad as ante- rior, ligamental edge nearly straight, not sloping, ventral edge little curved, anterior slope with deep divergent folds, the ridge little elevated, the folds indenting the edge; cuticle chesnut with a silky lustre; nacre flesh colour, becoming at the margin pearly white, with a narrow margin of dark chocolate: teeth large and elevated with afold behind. 2..3,3,.—N. America. Section B.—Smooth. U. DetroipEa.—Mare. D. Lea. on U. 2. p. 43. t. 13. f. 38. Ovate, inequilateral, compressed, thin, obliquely rounded posteriorly, obtuse anteriorly, the anterior ventral margin incurved ; beaks pro- minent, undulated at the tip and devoid of the green rays which elsewhere adorn the yellow cuticle: cardinal teeth erect, the lateral obsolete: nacre white and irridescent. -9,.. 12.— Ohio. U. Unpurata.—Axtasmoponta U. Say. Am. C. t. 16.— (Young.) A. Scutrtizis. Say.—Mya Unpounrata. Wood. S.t. 1. f. 5.—U. Grasratus. Sow. Transversely ovate, inequilateral, strong, much inflated, widely gaping, anteriorly attenuated and angulated, posteriorly and at the ventral edge rounded; beaks tumid elevated and undulated: cuticle shining dark green, with obscure linear rays alternately yellow and dark, nacre white; one cardinal tooth in each valve supported by a strong internal rib. 12..2.—Massachusets, §c. : U. Swananoensis.—Mare. Raveneviana. Lea. Trans. Am, Ph. 5, t. 17. f. 50. Transverse, oblong, anteriorly longer and P 2 212 TESTACEOUS MOLLUSCA. subcuneiform, posteriorly rounded, ligamental edge straight, ventral incurved in the middle; inflated, thin, beaks small, ligament shortish, umbonal slope large and rounded ; cuticle brown with rays ante- riorly, nacre bluish white: cardinal teeth small, rather compressed. 15... 2,4.—LV. Carolina. U. Rapiata.—Axasmoponta R. Conr. in Sil. J. 25. t. 1. ff. 10. Elongated-ovate, transverse, ventricose, posteriorly narrow and obtusely angulated, anteriorly produced and pointed at the end, ventral edge entire and rounded at the sides: beaks prominent and pointed at the apex which has two or three profound undulations, cuticle light. olive with beautiful dark green rays, nacre waxen yellowish: cardinal teeth elongated, in one valve distant, close under the beak in the other. 23a—S. Alabama. U. Caucrota. Lea. on U. 1. p.7.t. 3. f. 1.—ALASMODONTA. Trunecata. Conr. Transverse, suboval, inequilateral, ventricose, subcylindrical, thin, posteriorly rounded, anteriorly obtusely angu- lated both above and below, ventral edge not incurved, dorsal straightish and anteriorly ascending : beaks slightly undulated and touching, not decorticated : cuticle dark green, lighter towards the beaks, with indistinct rays, nacre white and silvery : cardinal tooth prominent., 4..14.—Ohio. U. Bonetui.—Axasmoponta B. Ferussac.—Derressa. Pfeif. t.8. f. 3, 4.—Rosm. f. 134. Oblong, compressed, thin, posteriorly attenuated, rounded and very short, anteriorly produced and dilated, ventral edge simple and scarcely arcuated : cardinal teeth coarse, a single one in each valve, no lamellar ones : ligamental sinus ovate. 24.—S. Germany. U. Paracuayana.—Monoconpyiea P. D’Orbig. Am. t. 70. f. 5, 6, 7. Ovate-subquadrilateral, inflated, thick, strigillated, posteriorly rounded short and narrow, anteriorly dilated, with an elevated sulcus radiating from the beaks and angulating at its extre- mity the arcuated ventral edge: beaks prominent, rounded, the cuticle thick, greenish brown: nacre greenish white, the tooth thick, elevated and obtuse. SS. America. U. Parcuarpiu. Lea.—Monoconnyxra P. D’ Orbig. S. Am, t, 68. f. 1, 2, 3. Ovate-oblong, compressed, striated, an- teriorly dilated, posteriorly short and rounded, ligamental edge straight, ventral entire and little arched; beaks eroded and not pro- minent, an indication of a lunule; the cuticle greenish brown ; inside rosy, the tooth prominent thick rounded and obtuse. 12..13.—S. America, U. Corrtentesinsis.—Monoconpytea C. D’Orbig. BS. Am. t. 68. f. 8, 9,10. Rounded-ovate, compressed, strigillated, greenish, posteriorly narrow short and rounded, anteriorly dilated rounded and with one or two green lines ; ventral edge strongly arcuated, beaks not prominent, no lunule, inside bluish white: tooth thick, broad, and prominent. 13..14.—S. America. TRIBE NAYADES. Ns U. Guarayana. Lea.—Monoconpyiea G. D’Orbig. S. Am. t. 68.f. 4, 5, 6, 7. Ovate, inflated very thick, striated, pos- teriorly short and rounded, anteriorly marked with two deep sulci, a prominent upper keel, and a large groove in the middle of the shell: beaks little prominent; with a lunule: inside pink, tooth little elevated, almost obsolete in one valve: 1}..132.—S. America. U. Fosstcutirerus. Lea—Monoconpyiea FF. D’Orbigq. in Mag. de Z. 1835. Ovate, compressed, thickish, wrinkled by striz, greenish brown, posteriorly much shorter and rounded, an- teriorly very broad and extremely dilated, seeming almost winged, the ligamental edge being above the level of the beaks and angulated at its extremity, umbonal ridge sharp, ventral edge much arcuated, beaks obtuse : within irridescent, white with violet spots, a tooth and fossicle in each valve. 3.—S. America. - U. Minuanus. JLea.—Monoconnyiea M. D?’ Orbig. S. Am. t. 70. f. 8,9, 10. Ovate-oblong, thick, inflated, smoothish or wrinkled, posteriorly short, rounded, and the dorsal edge incurved, anterior dorsal edge straight and angulated at its extremity : beaks prominent and lunate ; cuticle greenish, marked anteriorly with one or two greenish lines: inside greenish white, the tooth lamellar elevated obtuse. 14..12.—S. America. U. Marcaritirrrus.* Drap. 132. t. 10. f. 17, 8, 9.—Pfeif. t. 5. f. 11.—Ross. f. 72. 74. 129.—Turt. M. f. 9.—Mya M. Lin.—D. p. 52.—W.t. 2. f. 30.—List. t. 149.—Schre. F. t. 4. JF. 1.—U. Sinvata. Lam. § Pfeif.—U. Evoneata & Rorssyt. Michel. Elongated-oblong, transverse, inequilateral, rather com- pressed, thick, ‘heavy, black: brown, umbones usually eroded, and the ventral edge (save in the young,) incurved centrally and little arcuated ; anterior side twice as long as posterior ; its dorsal edge short with an obtuse angle at its end rounded posteriorly ; a short crested irregular posterior tooth in one valve, shutting between two inthe other. 3.—Hurope. U. Hotsroniranus. Zea.—Mare. H. Lea. on U. 2. p. 42. t. 13. f° 37. Transverse, very inequilateral, thinnish, oblong, rounded at both ends and the ventral edge incurved in the middle ; the beaks somewhat prominent and undulated; cuticle brown, wrinkled and apparently rayless ; nacre white "and irridescent : cardinal teeth large. 14..22.—R. Holston. U. Fasuza. ZLea—Mare. F. Lea. on U. 2. p. 442t. 13.:f- 39. Transverse, inequilateral, somewhat inflated, thickish, flattened on the side, suboblong, ventral edge incurved, umbonal slope raised ; beaks rather prominent, ligament short ; cuticle greenish with in- digninick rays, nacre salmon coloured : cardinal teeth small and erect. 2 ..4.— Tennessee. 214 TESTACEOUS MOLLUSCA. Division C. A linear tooth under the dorsal edge. U. Bravata. Desh. in Lam.—Diesas Puicatus. Leach.— Mytitus Dusrus. Gmel.—Anovon Dresas. Blain.t. 66. f. 3. —A. Atatus. Sow —Sympuonora B. Lea. on U. 1.p. 59. t.14. Triangular-ovate, inequilateral, subventricose, transversely and finely wrinkled, dorsal edge suddenly raised at its extremities into two wings, the anterior one the largest : valves thin, connate before and behind the beaks which are not prominent but undulated as well as the base and summit of the anterior wing: sides and ventral edge simply rounded : cuticles having yellow and purple brown with green oblique rays, nacre pearly and irridescent: one lamelliform curved tooth in each valve. 2 (from beak). .33.— Canton. U. Discoipevus. Lea.—Symrnonota D. Lea. Trans. Am. Ph. 5. t 11. f. 33.—U. Tenuis § Anov. T. Grif. Cuv. Transverse, subrhomboidal, dorsal edge nearly straight, ventral strongly arcuated; very thin, compressed, inequilateral, finely wrinkled, connate anteriorly : beaks very slightly undulated, com- pressed, ligament linear; cuticle dark brown, nacre white and irridescent ; teeth in both valves forming a simple line. 22. . 3-8; — Java? HYRIA. Equivalve, obliquely triangular, auriculated, the dorsal edge trun- cated and straight: hange with two little elevated teeth, the posterior or cardinal one divided into numerous diverging por- tions, (the inner portions being the smaller); the anterior or lateral tooth very elongated and lamellar, Ligament external and linear. H. Syrmaropuora. Sow. G. f. 1.— Reeve. t. 90. f. 1.—Mya S. Gronov. t. 18. f. 1.—D. p. 54.—W. t. 2. f.36.—List. t. 160. J. 16.—H. Avicutaris. Var. B. Lam. Ovate-subrhomboidal, dark olive, nearly smooth, hinge margin straight and forming short wings at its extremities, anterior edge almost direct and straight so as nearly to form a rectangle with the ventral : posterior side nar- row, the edge uniting with the ventral in an oblique curve : tumid, the anterior slope very flattened and bounded posteriorly by an obtuse ridge. 22.. Guinea ? H. Avicutartis. Lam. 1.— Del. t. 12. f.9.—H. Exoneara. Swain. Hx. Con. t. 24. Oblong-subtriangular, hinge margin with produced and narrow wings at its extremities : anterior edge form- ing an acute angle with the ventral edge, which forms one uninter- rupted line with that of the very attenuated posterior extremity : convex, nearly smooth, the cuticle brown and the anterior slope simple. 33.—Guiana. TRIBE NAYADES. yale H. Corrueata. Lam. 2.—E. t. 247. f. 2.— Reeve. t. 90. f. 2. —Mya Anocurata. W.S. t. 1. f. 12. Triangular, posteriorly narrower and obliquely rounded, the beaks with longitudinal wrinkles, which anteriorly become coarser and subdivided, with transverse groove-like striz; the ears short, the anterior one obtuse. —Variety. Sow. G. f. 2. The anterior ear sinuous at the base and somewhat plaited : cuticledark brown. 33.— Guiana. H. Brown1ana.—Unio B. Lea. on U. 2. p. 108. t. 24. f. 116. Triangular, inflated very inequilateral, winged anteriorly, thick; beaks prominent; epidermis striated, dark brown, nacre white ; cardinal teeth rather large and striated, lateral long and nearly straight. 1..2.—. Amazon. ANODONTA. Equivalve, inequilateral and transverse; hinge linear, without teeth ; dorsal edge glabrous, adnate and anteriorly either trun- cated or forming a sinus ; two lateral, remote, twin, muscular impressions ; ligament linear, external, sunk in a cleft at the anterior extremity. * No distinct angle at the posterior extremity of the hinge margin. SyMPHONOTE. A. Wanuamatensis. Lea. on U. 2. p 78. t. 20. f. 64. Obtusely triangular, winged, somewhat inflated, thin, inequilateral, connate over the ligament ; beaks rather compressed, yellowish and undulated at the tip, cuticle rather smooth and shining, having a small dark band at the line of growth near the margin : nacre white. 14..23.—Near the Rocky Mountains. A. Maentrica. ea.—Sympnonota M. Lea. Am. Ph. Tr. 1837. p. 43. t. 5. f. 14. Rounded-ovate, inequilateral, thin, very inflated near the beaks, the dorsal edge almost straight and sharply angulated at the extremities, the anterior edge obliquely sloping, the ventral simply but strongly arcuated ; beaks inflated and near the tips undulated ; cuticle smooth, yellow, with numerous green rays, nacre pearly and highly irridescent (sometimes tinged with salmon and pink); scars scarcely perceptible. 23,..3%.— Canton. A. Wooprana. JLea.—Sympnonota W. Lea. Am. Ph. Tr. 1837. f. 42. t. 5. f. 13. Transversely-ovate-subpentangular, thin, turned over the umbones, posteriorly very short, narrower and obtuse, anterior edge almost forming a right angle with the sinuated ventral which curves outwards near the middle ; anterior slope cari- nate ; ligamental edge nearly straight and direct: cuticle dark 216 ; TESTACEOUS MOLLUSCA. brown and obscurely rayed; beaks undulated, nacre pearly-white and irridescent. 24..3}3.— China. A. Brenepictensis. Lea.—Sympuonota B. Lea. in Am. Ph. Tr. 1837. t. 16. f: 48. Trapezoidal, transverse, inequilateral, rather compressed, very thin; dorsal line nearly straight ; forming an obtuse angle at each extremity, ventral edge scarcely arcuated ; beaks somewhat prominent and granulated at the tip; cuticle shin- ing yellowish olive; nacre bluish white and irridescent, scars scarcely perceptible, 21..33.—Lake Champlain. A. Nurrauiana. Lea.on U. 2. p.77.t. 20. f. 62." Winged, elliptical, flattened on the side and enlarged on the umbonal slope, ventral edge subincurved ; inequilateral, smooth, thin: beaks com- pressed and undulated at the tip: umbonal slope furnished with several impressed lines : cuticle smooth, polished, having a dark broad band at the line of growth near the margin: nacre white. 13... 2,3,. Non-Sympuonote.—A. Oval. A. Cyenea.* Lam. 1.—Myrtitus C. Lin. 1158.—D. p. 315.—W. t. 12. £32. Oval, tumid, rounder and ventricose pos- teriorly, compressed and more or less angular anteriorly, cuticle olive green; in the young the anterior slope is more dilated and compressed.— Variety 1. Myr. Cetuensis. Schre. t. 2.f. 1.— A. Sutcata. Lam. 3.— Turt. Man.t. 1. f. 8. Large, ovate- oblong, very ventricose, thin, brittle, rather produced anteriorly, upper and lower edges nearly parallel and straight.—Variety 2. Very like the last; but shorter and the lower edge rather more rounded.— Variety 3. Pen. 4. t. 67. f. 78. Very like the two former, but shorter and the lower edge still more rounded.— Variety 4. A. Piscrnauts. Drap. t. 12.f.2. Moderate, rather rhombic- oval, ventricose, rather thick, often beautifully coloured, produced anteriorly with the wing more compressed and elevated.— Variety 5. Rossm. t. 20. f. 284. Moderate, oblong, rather rhombic, rather compressed, brownish, much produced anteriorly, very short and rounded posteriorly.—Variety 6. InrERMepDIA. Lam. 10. Ross. t. 3.f. 68. Moderate, obovate, obliquely truncated anteriorly, compressed, striated, brownish green, and yellow zoned.—Variety 7. A. Ponprrosa. Rossm. 4. t. 20. f. 282. Moderate, ovate, rather rhombic, ventricose thick, solid rough, internally white, anterior slope subangular and rather truncated at the anterior ex- tremity, covered with a calcareous deposit.—Variety 8. Small elliptical ovate, brittle, rather produced anteriorly: short and rounder posteriorly. 7.—Hurope. A. Anatina. Lam. 22.—Myrtintus A. Lin. 1158.—D. p. 317.—Ch. f. 763. Ovate-oblong, fragile, posteriorly rounded, anteriorly subangulated, with unequal transverse grooves; beaks “TRIBE NAYADES. pall i retuse. Lurope.— Closely resembling Cygnea, but never so dilated posteriorly. A. Fraeruis. Lam. 4.— Del. t. 13. f.2. Narrow ovate, thin, very fragile, rhombic and compressed, anteriorly short and pos- teriorly rounded; with distant transverse grooves, ventral edge entire : beaks slightly prominent and undnlesing!y wrinkled; cuticle, greenish olive: inside bluish. 23.—Nemfoundland.— — Ohio. A. Fuuviatiuis. Lea.— Gould. Mas. p. 117. f. 80.—Myti- tus F. D.p. 316.—List. t. 157. f. 12.—W. t. 12. f. 35.—A. Cararacta. Say. in Nich. Enc. Amer. 4. t. 3. f. 4.—Lam. 5.—A. Mareinatus. Say.—A. Terres. Conrad. Suboval, thin, inflated ; hinge margin straight, posteriorly imperfectly angu- lated and nearly as high as it is anteriorly where it forms an obtuse angle at the termination of the ligament and declining in a straight line forms a somewhat produced blunted point (this margin is com- pressed into a sort of crest); ventral edge much arcuated ; beaks moderately elevated, situated at the posterior two-fifths of the shell, minutely undulated at the tip : cuticle deep grass green, obscurely rayed, darker above the anterior ridge ; nacre silvery or tinged with bluish or yellowish. 23..43}.—Massachusets, j'c.—Very like Cygnea. A. Crispata. Lam. 7.—E.t. 203.f.3. Oblong-ovate, rather depressed, thin, yellowish brown, contracted in the middle, with small crowded radiating flattened ribs decussated by numerous’ arched and undulated furrows. 2.—Beaks situated at two-sevenths from the narrowed and rounded posterior extremity. A. Untorsts. Lam. 8. Oblong-ovate, anteriorly subangulated, brown, transversely striated ; beaks rather prominent with the ligament passing between them and the hinge: within bluish to- wards the margin and the hinge plate thickish and terminated posteriorly by a somewhat prominent callus. 23. A. Unputata. Say. in Nic. Enc. Am. 4.t. 3.f. 6.—Gould. Mass. p. 120. f. 79.—A. Pensytvanica. Lam. 9.—Del.t. 13. f. 4.—A.Rueosus. Swain. Zool. Il. t. 96. Oblong-ovate, thick, posteriorly rather shorter and rounded, anteriorly very obtusely bi- angulated, dorsal and ventral edges subparallel and but little arcuated: beaks prominent, with four or five small undulations ; cuticle dark brown, radiated, coarsely wrinkled towards the ventral edge; inner disc pale salmon, inner margin broad, olive; hinge margin undulated and with the vestige of a tooth. 2..33.—Mas- sachusets. A. Exotica. am. 12.—Del.t.13.f.1. Ovate-oblong, thick, transversely grooved and the cuticle olive green, much attenuated posteriorly ; posterior end of hinge margin terminated by an angle ; ventral edge posteriorly A bes ok beaks prominent, cardinal sinus large ; irridescent within. 53 -— Peru. 218 TESTACEOUS MOLLUSCA. A. Epentuta. Jea.—Arasmoponta E. Say.—An. AREo- Latus. Swain. Zool, Ill. 2d series. Transversely-oval, inequi- lateral, sides rounded both above and below, convex, ventral edge arcuated, ligamental edge direct; umbones small, bent, not touch- ing; with a short undulated projection of the hinge margin in one valve and a corresponding concavity in the other, both placed beneath the umbones ; cuticle dark olive, smooth. 2.—N. America. A. Pavonia. Lea. on U. 2. p. 78. t. 21. f. 65. Elliptical, in- flated, inequilateral, thin: beaks somewhat prominent and with rather large undulations at the tip : ligament rather short and thin: cuticle smooth shining, with numerous dark green rays which diverge to the whole margin: nacre bluish. 13..3.— Ohio. A. Limnorca. D’Orbig. in Mag. de Z. 1835. Oblong, sub- inflated, rather smooth, thin, green, short and rounded posteriorly, elongated broad, almost angulated, yellowish, anteriorly ; nacre pink. 14..2.—S8. America. A.Trigona. Spix. Test. Braz. t.22.f.2. Ovate-triangular inequilateral, compressed solid, transversely grooved, with a longi- tudinal gibbous elevation in the middle; anteriorly somewhat beaked and acuminated, posteriorly rounded, ventral edge anteriorly incurved; dorsal edge straight anteriorly angulated and winged : beaks depressed and decorticated, umbones flattened. 1..13.— Brazil. A. Purpurea. Valen. Zool. to Humb. voy. t. 48. bis. f. 3. Transverse, elliptic, rich brown, transversely striated; dorsal edge nearly straight ; anterior side compressed, the edge obtusely angu- lated, the slope not ridged ; ventral edge incurved in the middle : beaks decorticated ; inside purple. 13..21.—Philippines. A. Ferussacciana. Lea. Am. Ph. Tr. 1837. t. 6. f. 15. p. 45. Oblong-subcylindraceous, thin, inequilateral, inflated, ventral and ligamental edges nearly straight and subparallel (the former very slightly incurved,) dorsal margin curved immediately under the point of the beak; posteriorly rounded shorter and narrower, an- teriorly somewhat angulated: cuticle dark olive, shining, with obsolete rays ; beaks somewhat prominent, very slightly undulated ; nacre bluish white and irridescent : scars perceptible. 14..3}.— Ohio. A. Satmonia. Lea. on U. 2. p. 45.t. 14. f. 41. Elliptical, transverse, inflated, very inequilateral, within salmon colour, and usually very rough ; thin, ventral edge subincurved; beaks some- what prominent and slightly undulated at the tip, the ligament rather short ; cuticle dark brown, sometimes with yellow bands. 12... 2455-— Ohio. A. Incerta. Lea. Am. Ph. Tr. 1837. t. 6. f. 16.—ImpBr- cituis? Say. Elongated-elliptic, very thin, inflated, posteriorly shorter and rounded, anteriorly subangulated ; dorsal line nearly TRIBE NAYADES., 219 straight subparallel to the ventral which is scarcely at all arcuated : beaks flattened and minutely undulated : cuticle very smooth, green and olive green with obsolete rays (the three anterior more distinct) nacre bluish white and irridescent, scars nearly perceptible. 12... 31, — Ohio. - A. Newronensis. Lea. on U.2. p.79.t. 21. f. 66. Narrow elliptical, inflated, thick, ventral edge entire, inequilateral ; beaks somewhat prominent and rather largely undulated at the tip: liga- ment rather short : cuticle dark brown, shining, apparently ray- less : nacre white, sometimes salmon. 2;3,..43.—New Jersey. A. Mortoniana. Lea. Am. Ph. Tr. 1837. t. 13. f. 37.— A. Cusauitana. D’ Orb. in Mag. de Z. 1835. Transversely sub- elliptical somewhat inflated, thick, the ventral and ligamental edge nearly parallel and scarcely curved, anteriorly subbiangulated, pos- teriorly very short and narrow : grooved along the umbonal slope ; beaks retuse and scarcely prominent : cuticle intensely brown and slightly wrinkled ; nacre silvery white and irridescent. 12. .3.— R. Parana, S. America. A. Ovata. Lea. on. U. 2. p. 2.t. 2. f. 2. Ovate, somewhat compressed, transverse inequilateral, thinnish, ventral edge rounded; beaks somewhat prominent and granular at tip; ligament rather short : cuticle greenish brown, wrinkled, apparently rayless ; nacre white or bluish. 21..4.—Ohio. A. Piana. Lea. Am. Ph. Tr. 1837. t.7.—Decuivis. Conr. -Ovate-oblong, inequilateral, thick, rather compressed, anteriorly subangular, dorsal line slightly curved, ventral edge but slightly arcuated, posterior side but little narrower ; beaks elevated, granular at the tip; cuticle smooth, olive to dark green, brighter on the beaks, rays obsolete; nacre white (rarely salmon near the beaks,) sears perceptible. 3,1,..53.—Louisville, N. America. A. Decora. Lea. on U. 2. p. 64. t.20.f. 63. Elliptical, thin, nearly straight on the dorsal margin, inequilateral, angular an- teriorly ; beaks rather prominent and undulated in a double series at the tip; ligament rather long and straight; cuticle smooth and shining, rayed with green beyond the subcentral dark band; anterior slope dark, with three rays: nacre white just tinged with salmon in the cavity. 23..3-9,.— Ohio. A. Gigantea. Lea. on U. 2. p.1. t. 1. Ovate oblong, inflated, thick, posteriorly broad, anteriorly very produced and subcuneiform from the great slope of the ligamental margin ; beaks prominent, granular at tip ; cuticle dark brown, smooth ; ventral edge incurved anteriorly ; nacre white and richly pearly. 44..74.—-Port Gibson.) A. OrEGoNENSIS. Lea. on U. 2. p. 80. t. 21. f. 67. Some- 1 Add likewise the A. Susvexa of Conrad. 220 TESTACEOUS MOLLUSCA. what winged, rather inflated, elliptical, inequilateral, thin: beaks scarcely prominent and undulate at tip; cuticle olive somewhat shining and striate; nacre white. 14..31.—Near the Rocky Mountains. A. Peprntana. Lea. on U.2.p.96. t. 16. 7.51. Trapezoidal, inequilateral, rather inflated, flattened on the sides, thin, transverse, carinate anteriorly: beaks prominent: umbonal slope rather elevated and rounded : cuticle transversely striated, with the lines of growth strongly marked and apparently without rays ; nacre white. 11..2.—Ohio.! A. Warpiana. Lea. on U. 2. p. 46. 4.14. f. 42. Elliptical transverse, thin, somewhat inflated, inequilateral, at the base sub- emarginate, dorsal margin curved under the beak : umbonal slope rounded : beaks prominent, concentrically undulated at the tip: ligament rather short; cuticle green, disposed to be yellow on the anterior slope and the beaks: nacre bluish. 1-4,..3.—Ohio. A. Stewartiana. Lea. on U. 5: in Amer. Phil. Tr. 6. ‘Rounded-ovate, very thin, much inflated, anteriorly subangulated, posteriorly short and narrower, dorsal line rather short, nearly straight and forming obtuse angles at both extremities, ventral edge convex ; beaks prominent and granulated at the tip in a short double series ; cuticle roughish, olive green, obtusely rayed; nacre bluish white, irridescent, sometimes tinged with salmon colour about the beaks. 2.. 3 1,.—Louisiana.? A. Granpis. Say. in Transylvania Journal.—A. Corpu- LENTA. Cooper. Very large, subovate ; disc unequally wrinkled and undulated transversely, dark yellowish brown : umbo elevated; beak slightly elevated, with generally two or three small sinuous acute undulations ; hinge margin slightly arcuated, sometimes nearly rectilinear, somewhat angulated at its anterior termination, thence the edge descends by a nearly rectilinear or slightly concave line to the anterior margin, which is considerably narrowed; sinus of the hinge margin concave ; posterior margin widely rounded ; within white margined particularly in front, with dusky. 5..7%. —R. Wabash. B. Obovate. A. Trapeziatis. Lam. 11.—Ch. f. 762.--E. t. 205. fi 1.— Exot. Conch. t. 36. Ovate, fragile, tumid, posterior slope elevated compressed and more winged than the anterior, pale yellowish olive subradiated posteriorly by darker lines: umbones broad, 1 Add likewise the A. CHarziana. Rang. ® Add likewise the A. Gipposa of Say. TRIBE NAYADES. 221 smooth, and prominent: within pearly, with purple stains beneath the hinge. 34. A. Grauca. Lam. 13.—Del. t. 13. fi 3.—Valen. in Hum. Zool. Obovate, tumid, thin, fragile, obsoletely rayed, with green on an olive ground, compressed and winged anteriorly, posteriorly very short, narrower and obliquely rounded at the ventral margin. 33.—Acapuleo in America. A. Paraconica. Lam. 15.—E. t. 203. f. 1. Obovate, anteriorly angulated, compressed and carinated on the anterior slope, yellowish or brownish green, with concentric transverse strive and grooves ; beaks slightly prominent; sides rounded ; ventral edge simply arcuated, not incurved ; sinus of posterior hinge margin very short, incurved and angulated at its extremity. 3.—Patagonia and La Plata. ! A. Ostusa. Spia. Test. Braz. t. 22. f. 3,4. Oblong-ovate, obtuse, very slightly dilated anteriorly, solid, transversely grooved : dorsal edge straightish, winged and angulated at each extremity ; beaks prominent and decorticated: umbones flattened and smoothish, edges thin and sharp: cuticle olive with obsolete radiating blackish lines, (in the young with additional angularly flexuous transverse ones ;) nacre bluish and irridescent. 13..2.—Brazil. A. Srrronos. D’Orbig. in Mag. de Z. 1835. Obovate, compressed, thin, olive coloured, very inequilateral, the posterior side narrowed, ligamental edge elevated and angulated at the extre- mity, the posterior dorsal edge short and incurved, posterior edge obliquely sloping to meet the much arcuated ventral margin : nacre greenish. 23..4.—Bolivar. A. Latomarainata. Lea. Am. Ph. Tr. 1837. t. 12. f. 34.— D Orb.—A. Trarezius? Spix.—A. Rorunpus? Spia. Trans- versely obovate, inflated, thick, posteriorly very short and narrow, anteriorly dilated and obtuse, dorsal line little curved: cuticle reddish brown, finely wrinkled ; nacre pearly white and irridescent, with a broad horn-coloured border at the rounded ventral edge; sinus long and pointed to the interior of the disc. 2}..33.—R. Parana, 8S. America. A. Sprxir. D’ Orb. in Mag. de Z. 1835.—A. TRAPEzIUM. Spix. Braz. t. 20. f. 1. Ovate-trapeziform, ventricose, anteriorly dilated and rounded, posteriorly much narrower, thick, trans- versely striated ; dorsal line somewhat curved, the anterior slope elevated and obtusely angulated, posteriorly terminated by an acute angle ; margins attenuated and acute: beaks prominent, inflexed, decorticated ; umbones inflated ; hinge-lamina somewhat curved and terminated anteriorly by an angular sinus: cuticle olive green, nacre smooth, bluish-white irridescent. 2..24.—Brazil. A. Porcirer. Gray. Z. P. 1834. Ovate, subventricose, thick, 20° TESTACEOUS MOLLUSCA. solid, posteriorly convex and rounded, anteriorly produced, with an angular ridge near the depression of the anterior margin ; ventral margin anteriorly roundish ; disc very glossy, irridescent, pearly, cuticle black with green rays. Paraguay. A. AnserinA. Spix. Test. Braz. t. 21. Ovate-oblong, anteriorly dilated, posteriorly somewhat narrowed, solid, transversely grooved : dorsal edge straight, the anterior slope elevated, com- pressed and winged, posteriorly ending in an acute angle: beaks decorticated and rather prominent, hinge margin ending anteriorly in atriangular sinus ; cuticle olive, nacre bluish and irridescent. 1. .45%.— Brazil. A. Parisuit. Gray. Z. P. 1834. Ovate, ventricose, solid posteriorly compressed, somewhat produced and rather slender ; anteriorly expanded, dilated and rounded; hinge margin straight, equalling in length the half of the ventral: disc pearly white ; cuticle blackish brown. 32..73.—Paraguay. A. Buainviniiana. Lea. Am. Ph. T'r. 1837. t. 12. f. 35.— Trapeziatis. Crouch. Lam.—-Iripina F. D’ Orb. Subovate, transverse, inflated, thickish ; posteriorly very short and extremely narrow, the straight dorsal line forming an acute angle with the arcuated ventral ; anteriorly much dilated, obtusely biangulated ; gaping at both ends; beaks somewhat prominent ; palleal scar broad and much incurved anteriorly ; cuticle greenish ? nacre salmon and pearly. 1,9,.-.3. Chili? A. Crassa. Swain. Z. Ill. 1st. ser. ¢t. 167. Oval, broad, thick, hinge margin subarcuated, raised anteriorly, and sharply angulated at both extremities ; ventral edge much arcuated, rounded anteriorly and meeting the posterior in an uninterrupted very oblique sweep; umbonal slope elevated and somewhat angulated, umbones thick and prominent, but obtuse at their apex ; cuticle dark grass green, nearly smooth, except anteriorly where the lines of growth are coarse. . A.Anouuata. Lea. on U. 2. p.97. t. 16. f. 52. Subcunei- form, posteriorly shorter, compressed, attenuated and rounded at the tip, anteriorly inflated, winged angulated above and below: the dorsal edge ascending, ventral edge nearly straight: cuticle green and smooth ; (but the anterior slope is rugged and strongly carinated:) nacre salmon. 2$.—California. C. Round. A. Susorpicutata. Say. Am. Con. t. 11. Ovate orbicular, rather compressed, inequilateral, pale olivaceous tinted with flesh- colour, with very slender and numerous almost capillary obsolete greenish radii (sometimes with more or less obvious transverse yel- TRIBE NAYADES. 223 lowish bands towards the base :) beaks not elevated: hinge margin rectilinear compressed posteriorly, and anteriorly compressed. 3 almost to a wing, ligament almost concealed: posterior margin rounded, anterior a little prominent obtusely angulated, ventral much arcuated ; inside as much undulated as without, pale bluish varied with pale flesh. 4..95,3;.—N. America. D. Wide. A. Exoneata. Swain, Z. Il. 1st. ser. Transversely elongated oblong, convex, thick, posteriorly very short and rounded above and below, anteriorly produced compressed attenuated but rounded at the tip, ventral edge little arcuated and incurved subcentrally ; cuticle fulvous, nearly smooth, umbones convex, remarkably thick and deeply eroded : inside pearly and irridescent with a tinge of flesh colour, hinge plate rather convex. 1}..23.—S. America? A. Enstrormis. Spix. Test. Braz. t. 24.—D’ Orb. Trans- verse, four times as broad as long, posteriorly rounded and very short, anteriorly produced into a long attenuated beak, thick, transversely furrowed, ventral edge incurved ; beaks retuse, decorticated, um- bones depressed ; cutile olive, nacre bluish and _irridescent. 13 ..43.— Brazil. A. Cytinpracea. Lea. on U. 2. p. 45. t. 13. f. 40. Subcylindrical, very transverse, posteriorly very short and rounded, anteriorly produced and rounded biangular, the ligamental edge straight and long, ventral incurved and little rounded: thin, the cuticle dark brown covered with capillary rays: umbonal slope rounded : beaks somewhat prominent : nacre blue and irridescent. 13,..235.—Vera Cruz. A. Suscyyinpracea. Lea. on U. 2. p. 106. t. 24. f.117. Ellip- tical, twice as broad as long, subcylindraceous, very thin, posteriorly short and rounded, anteriorly produced and obtuse, ligamental and ventral edges nearly straight, the latter subincurved : beaks some- what prominent and minutely undulated at the tip: cuticle brown and rayless: nacre bluish and irridescent. 21.— Nem York. A. Bucuanensis.' Lea.on U. 2. p. 47. t. 14. f. 23. Trans- verse inflated, thin, subcylindrical, posteriorly short and rounded, anterior very produced and obtuse, ventral edge incurved, sides flat- tened ; umbonal slope elevated and rounded ; beaks somewhat prominent and minutely undulated : cuticle greenish, darker on 1 Add likewise the A. ArcuaTA of Ferussac, the A. Esuxa of Cristofori and Jan’s Catalogue (I7ridina E. of D’Orbigny) and the A. Georgine of Gray figured (Mollusca, t. 19. f. 23.), but not described in Griffith’s edition of Cuvier. 224 TESTACEOUS MOLLUSCA. me anterior slope: nacre white, bluish anteriorly. 1,..3.— v0. A. Stnvosa. Lam. 14.—Z£. t. 203. f. 2. Oval, transversely striated, contracted at the ventral margin, hinge margin waved and sinuous, being concave at the posterior extremity, with whose edge it forms a sharp angle: beaks moderately prominent, smooth, and spotted with violet: brilliant and irridescent within. 341. A. Exinis. Lea. on U.2. p. 81.1. 22. f.68. Wide, very much compressed, very thin, slender, rounded and very short posteriorly, produced and angulated anteriorly: beaks scarcely prominent ; ligament long and thin ; cuticle smooth brown, apparently rayless : nacre bluish and irridescent. 12..62. A. Tenesricosa. Lea. in Am. Ph. Tr. 1837. t. 12. f. 36.— D> Orb. in Mag. de Z, 1835. Subelliptic, transverse, thick, rounded above and below at both extremities, dorsal line little curved, ventral edge incurved in the middle; posterior side short and nar- rower, ligament long and thick: cuticle dark olive brown, wrinkled, obscurely rayed on the anterior slope ; nacre pearly white, clouded with bluish purple, irridescent, with a broad horn-coloured border : sinus incurved. 1,%,..3,3,. &. Parana, S. America.’ 1 However closely approximating Anodon, the genus Mycetopus, cannot (being subequilateral,) be strictly included under Lamarck’s definition of that genus. MYCETOPUS. D’Orsreny. Thin, extremely elongated transversely, subarcuated, equivalve, subequilateral, gaping at both ends, (chiefly so posteriorly) clothed mith an olive green cuticle, bluish internally ; umbones central, biangulated, curving inwards: hinge linear, straight, toothless ; ligament marginal and thin: muscular impressions rather indistinct, compound. M. Sotentrormis. D’ Orb. Mag. de Z. 1835. p. 41.—Reeve. Sy.t.94. Extremely elongated, subcylindraceous, subarcuated, in- flated, thin, rather smooth, greenish brown; beaks central, anteriorly rounded ; posteriorly biangulated broad ; ventral edge concave ; bluish within. 2..9.—Bolivar. M. S1ziquosus. D’Orb. in Mag. de Z. 1835.—Anopon 8. Spic. Test. Braz. t. 23. f. 2.—A. Lonernum. Spi. t. 22. f. 2. A. Pyamaum. t. 23. f. 34. Elongated, compressed, straight, extremely thin, smooth, pellucid, yellowish green ; beaks thrice as near the posterior as the anterior, anteriorly truncated and rounded, posteriorly long and broad, subrhomboidal; ventral edge convex : inside bluish white. 14..6.— Bolivar. SYSTEMATIC LIST OF THE SHELLS FIGURED IN THIS WORK, WITH REFERENCES TO THE DESCRIPTIONS. ASPERGILLUM. Javanum p. 1, t. 38. f, 34. Vaginiferum p. 1. sup. t. 9. f.23. Nove Zelandiz p. 2. sup. t. 9. f, 54. Agglutinans p.2. sup.t.10.f. 19. CLAVAGELLA. Aperta p. 2. sup. t. 9. f. 21. Elongata p. 2. sup. t. 11. f. 1. 2. Lata p. 2. sup. t. 11. f. 4. Melitensis p. 2. sup. t. 11. f. 3. Australis p. 2. sup. t. 9. f. 22. Balanorum p, 2. sup. t. 10. f. 21. FISTULANA. Clava p. 3. sup. t. 11. f. 5. Gregata p. 3. t. 38. TER. f. 4. Lagenula p. 3. sup.t. 13.f. 59. SEPTARIA. Arenaria p. 3, t. 38. rr. f. 1. TEREDO. Navalis p. 3. t. 38. TER. f. 2. Palmulata p. 4. sup. t, 11. f. 13 Bipennata p. 4. sup. t. 9. f. 50. Corniformis p. 4. t. 38. TER. f.3. and sup. t. 9. f. 49. Nana p. 4. sup. t. 11. f. 22. Malleolus p, 4. sup, t. 11. f. 23. PHOLAS. Dactylus p. 5. t. 2. f. 1. Orientalis p. 5. t. 2. f. 2. Candida p. 5. t. 2. f. 3. Parva p. 5, t. 2. f. 6. Silicula p, 6. sup. t. 9. f. 58. Costata p. 6. t. 2. f. 4. Truncata p. 6. sup, t. 9. f. 26. Crucigera p. 6. sup. t. 11. f. 53. Campechensis p. 6. sup. t. 9. f. 44, Clausa p. 6. sup. t. 11. f. 8. Crispata p. 7. t. 2, f. 5. Clavata p. 7.%: 2. f. 7. Ovum p. 7. sup: t. 1. f. 4. Paleatap. 7. t.72.4.78; Acuminata p. 8. sup, t. 9. f. 30. Californica p. 8. sup. t. 9. f. 43. Papyracea p. 9. sup. t. 1. ies Oe Tuberculata p. 9. sup. t. 1. f. 3. Xylophaga Dorsalis p. 10. sup. te Ud teas Xylophaga Globosa p. 10. sup. t Set -5 1. GASTROCHENA. Cuneiformis p. 10. t. 2. pHoL. ode. Mytiloides p. 10, sup. t. 9. f.37. Modiolina p. 10. t, 2. f. 23, Truncata p. 10. sup, t. 9. f. 40. Ovata p. 10. sup. t. 9. f. 42. SOLEN. Vagina p. Il. t. 3. f. 3. Corneus p. 11, sup. t. 10, f. 42. Vaginoides p.11.sup.t. 1. f. 2. Siliqua p. 11. t. 3. f. 1. Ensis p. 11. t. 3. f. 6. Linearis p. 12, t. 3. f. 5, Scalprum p. 12. sup. t. 11. f. 26. Sloanii p. 12. sup. t. 11. f. 18, Truncatus p. 12. t. 3. f..4. Guinensis p. 12, sup. t. 13. f, 28- Brevis p. 12. sup. t. 13. f. 42. Thuelcha p. 13, sup. t. 10. f. 30. Pygmeus p. 13. t. 3, f. 7. Ambiguus p.13. sup. t. 11. f.17. Cultellus p. 13. t. 3. f. 9. Planusp.13. t..3. f.17% Legumen p. 13. t. 3. f. 8. Dombei p. 13. sup. t. 9. f. 19. Javanicus p.14. sup. t. 11. f. 19. Caribeus p. 14. t. 3. f. 15. Coarctatus p. 14. t. 3. f. 10. Strigilatus p. 14. t. 3. f. 12. Radiatus p. 14. t. 3. f. 14. Politus p. 14. sup. t. 1. f. 6. Candidus p. 15. sup. t. 11. f. 29. Solidus p. 15. sup. t. 9. f. 16. Inflexus p. 15. t. 3. f. 18. Orbiculatus p. 15. sup. t. 1. f. 4. Costatus p. 15. sup. t.9. f. 28 Medius p. 15. sup. t. 10. f. 18. Maximus p. 15. t. 3. f. 16. Bidens p. 16. t. 3. f. 11. Tenuis p. 16. sup. t. 1. f. 5. Novaculina p16, sup. t. 10. f. 7. Californianus p. 16. sup. t. 10. f. 4. Acutidens p.17, sup. t. 11. £.36. Acuminatus p. 17. sup. t. 11. f. 35, Niveus app. sup. t. 12. f. 40. Cylindraceus app. sup.t. 12. f.41 Philippinarum are. sup. t. 12. f. 42. GLAUCONOME. Chinensis p.17. sup. t. 10. f. 17. Rogosus app. sup. t. 10, f. 24. SOLENELLA. Norrisii p. 17. sup. t. 10. i PANOPZEA. Aldrovandi p. 18. t. 3. f. 41. Zelanica p. 18. sup. t.9.f.59. Australis p. 18. sup. t.9. f. 24, Arctica p. 18. sup. t. 10. f. 43. PHOLADOMYA. Candida p. 18. sup. t. 9. f. 57. GLYCIMERIS. Siliqua p. 19. t. 2. f. 10. Membranacea : (Anatina. M. p- 23.) t. 2. f. 14. MYA. Truncata.p. 19. t. 2. f. 1. Arenaria p. 19. t. 2. f. 2. Cancellata p.20. sup, t.13. f. 60. Semistriata p.20. sup. t.10. f, 16. ANATINA. Lanterna p. 20. t. 3. f. 30: Truncata p, 20. sup, t. 11. f. 24. Subrostrata p. 20, t. 3. sox. f. 1. Globulosa p. 20, t. 2. mya. f. 6. Globosa p. 23. t. 2. mya. f. 5. Elliptica p. 23. sup. t. 9. f. 46. Pretenuis p. 23. t. 2. mya. f, 3. Distorta p. 23. t, 2. f. 15. Papyracea p.23.sup.t.10.f. 12. Leana p. 24. sup. t. 9. f. 33. Elongata p. 24, sup.t. 10. f. 15. MYODORA. (aprP.) Brevis (Anatina B. p, 24.) sup. t.. 10. fda. Ovalis ( O. p. 25.) sup. t.9. f. 53. Pandoriformis (Anat. P. p, 25.) sup. t. 10. f. 9: Crassa (Anat. C, p. 25.) sup. t. 1) 8 eR Striata (Pandora S. p. 50.) sup. trie fk. Ia. PERIPLOMA. Argentaria p.21. sup. t.10.f. 11. Planiuscula p, 21. sup. t, 10. £. 33% Obtusa app. sup. t. 13. f. 50. Trapezoides (Anatina T. p.20.) sup. &.. 105 £32; THRACIA. Pubescens p. 21. t. 2. mya. f. 4. Plicata p. 21. sup. t. 10. f.37. Declivis (Phaseolina p.22.) sup. 4, 10, f., 350. Similis p. 22. sup. t. 9. f. 52. Conradi p. 22. sup. t. 10. f. 34. Convexa p. 22. t. 2. mya. f. 3. Corbuloides p.22. sup. t.9. f. 20. Curta p. 22. sup. t. 10, f. 1. LYONSIA. (OstrEopEsma.) Nitida (Corbuloides p. 24.) t.2. £7033 Hyalina p. 24. sup. t. 10. f. 10. Elongata p. 25. sup. t. 13. f. 27. Cuneata p. 25. sup. t. 10. f. 14. LUTRARIA. Solenoides p. 26. t. 6. f. 37. Elliptica p. 26. t. 6. f. 36. Rugosa p. 26. t. 6. f. 33. Egyptiaca p. 26. t. 6. f. 34. Ensis p. 27. sup. t. 10. f. 26. Compressa p. 27. t. 6. f. 25. Tellinoides p. 27. sup. t. 11. f. 33. Papyracea p. 27. sup. t. 1. mac. f; 2. Canaliculata p. 27. sup. t. 1. f.3. Complanata p. 28. t. 6. f. 35. Cottardi p. 28. sup. t. 9. f. 56. Vitrea p. 28. t. 6. f. 4. Squamosa p. 28. sup. t.9. f..47. Nicobarica (Anatina N. p. 23.) t. Qa de 1, Cyprinus p. 28. sup. t. 1. f. 1. MACTRA. Solidissima p. 28. t. 6. f. 22. Spengleri p. 29. t. 6. f. 1. Striatula p. 29. sup. t. 1. f. 7. Glauca p. 29. t. 6. f. 30. Stultorum p. 29. t. 6. f. 18. Grandis p. 29. t. 6. f. 19. Maculosa p. 29. sup. t. 11. f. 27. Nitida p. 30. t. 6. f. 13. Glabrata p. 30. t. 6. f. 12. Violacea p. 30. t. 6. f. 9. Fasciata p. 30. sup. 10. f. 39. Turgida p. 30. t. 6. f. 8. Plicataria p. 30. t. 6. f. 2. Rufescens p. 30. sup. t. 10. f. 20. Maculata p. 30. t. 6. f. 7. Subplicata p. 31. sup. t. 1. f. 6. Triangularis p. 31. sup. t. 10. f. 40. Lactea p. 31. sup. t. 107 f. 41. Ovalina p. 31. sup. t. 10. f. 23. Alba p. 31. sup. t. 10. f. 27. Solida p. 31. t. 6. f. 21. Squalida p. 31. sup. t. 11. f. 30. Brasiliana p. 31. sup. t. 10. f.60. Pellucida p. 32. t. 6. f. 32. Lisor p. 32. sup.t. 11. f. 54.55. Truncata p. 32. sup. t. 9. f. 1. Subtruncata p. 32. t. 6. f. 23. | Australis p. 32. sup. t. 10. f. 36. Elegans p. 33. sup. t. 11.f. 16. Vitrea p. 33. sup. t. 10. f. 28. Cygnea p. 33. t. 6. f. 6. Exoleta p. 33. sup. t. 11. f. 51. Elongata p. 33. sup. t.10. f. 2. Similis p. 33. sup. t. 1. f. 5. Aspersa p. 33. sup. t. 1. f. 4. Saulii p. 34. sup. t. 13. f. 24. Nucleus p, 34. sup. t. 12. f. 11. Cuneata p. 34. t. 6. f. 10. Achatina p. 34. t. 6. f. 20. Mulinia Bicolor p. 34. sup. t. 10. f. 31. Mulinia Lateralis p. 34. sup. t. 10..f. 25. Mulinia Donaciformis p. 34. sup. t. 10. f. 29. Mulinia Byronensis p. 35. sup. €40.4.88: GNATHODON. Cuneatus p. 35. sup. t. 10. f.22. GRASSATELLA. Kingicola p. 35. sup. t. 12. f.17. Donacina p. 36. sup. t. 10. f. 58. Sulcata p. 36. sup. t. 12. f. 22. Rostrata p. 36. sup. t. 9. f. 31. Subradiata p.36. sup. t. 12. f.14, Contraria p. 36. t. 8. f. 95. Castanea p. 36. sup. t. 12. f. 23. Decipiens p. 36. sup. t. 11. f. 9. Pulchra p. 36. sup. t. 12. f. 18. Lapidea p. 36. sup. t. 10. f. 59. Jubar p. 37. sup. t. 12. f. 25. Corbuloides p. 37. sup. t. 12. f. 15. Triquetra p. 37. sup. t.10. f. 54. Ornata p. 37. sup. t. 12. f. 13. Undulata p. 37. sup. t. 12. f. 24. Gibbosa p. 37. sup. t. 12. f. 16. Radiata p. 37. sup. t. 11. f.15. MESODESMA. Donacium p. 38. sup.t. 10. £.56. Glabratum p. 38. sup. t. 1. mac. f. 12? Complanatum p. 38. sup. t. 10. f, 55. Cuneatum p. 38. sup. t. 1. mac. f..8. Erycineum p.38. sup. t.12. f. 26. Striatum p. 38. t. 6. mac. f. 16. Chemnitzii p. 38. sup. t. 1.f. 11. Donacillum p.39. sup. t.11. £.39. Corneum p. 39. sup. t. 11. f. 40. Glabellum p. 39. sup. t. 11. f. 6. Solenoides p. 39. sup. t. 10.f. 3. Arctatum p. 39. sup. t. 9. f. 55. Deauratum p. 39, sup.t. 1. mac. f. 9. Castaneum p. 39. t. 6. f. 10. Triquetrum app. sup. t.12.f.20. Planum arp. sup. t. 12. f. 19. ERYCINA. Cardioides p. 40. sup. t.10. f.57. Geoffroyi p.40. sup. t. 12. f. 1. MONTACUTA. Ferruginea p. 40. t. 2. f. 19. KELLIA. Rubra p. 43. sup. t. 9. f. 48. Suborbicularis p. 43. t. 3. f. 37. ERVILIA. Nitens p. 43. t. 3. f. 37. UNGULINA. Oblonga p. 40. sup. t. 10. f. 44. SOLEMYA. Australis p. 41. sup. t. 11. f. 25. Mediterranea p. 41. sup. t. 1. soLEN. f. 1. AMPHIDESMA. Variegatum p. 41. t. 3. f. 17. Boysii p. 41. t. 6. f. 27. Tenue p: 41. t. 6. f. 26. Prismaticum p. 41. t. 6. mac. f 21" Decussatum p. 43. t. 4. f. 81. Solidum p. 43. sup. t. 12. f. 32. Cordiforme p. 43. t. 4. f. 82. Corrugatum p. 44. sup. t. 12. f.5. and var. t. 12. f. 21. Australe p. 44. sup. t. 12. f. 8. Rupium p. 44. sup. t. 12. f. 50. Leeve p. 44. sup. t. 12. f. 10. Purpurascens p. 14. sup. t. 12. f. 45. Formosum p. 44. sup. t. 12.f.48. Pallidum p. 44. sup. t. 12. f. 44. Roseum p. 44. sup. t. 12. f. 35. Lenticulare p.44.sup.t.12.f.49. Rubrolineatum p. 44. sup. t. 12. BS) Decisum p. 44. sup. t. 12. f. 52. Pulchrum p. 45. sup. t. 12. f. 4. Punctatum p. 45. sup.t.12.f.46. Zebuense arp. sup. t. 12. f. 7. Scabrum app. sup. t. 12. f. 9. CUMINGIA. Tellinoides app. p.42. sup. t.12 f. 38. Coarctata app. sup. t, 12. f. 37 CORBULA. Sulcata p. 45. sup. t. 13. f. 48. Tahitensis p. 46. sup. t.12.f. 30. Nucleus p. 46. t. 3. f. 40. Porcina p. 46. sup. t. 12. f. 47. Cuspidata (erroneously Rostrata of Desh.—p.46. ) t.2.f.12? Bicarinata p. 46. sup. t.12.f.31. Rostrata of Sow. p.46.sup.t.10. f. 53. Labiata p. 47. t. 3. f. 39. Contracta p. 47. sup. t. 9. f. 34. Mediterranea p. 47. sup. t. 12. f. 43. Biradiata p. 47. sup. t. 10. f. 51. Ovulata p. 47. sup. t.1. f. 52. Binghami p. 47. sup. t. 2. f. 4. Rupicola p. 47. sup. t. 11. f. 32. Crassa App. sup. t. 12. f. 29. Rosea arp. sup. t. 12. f. 33. Quadrata app. sup. t. 12. f. 36. Trigona app. sup. t. 12. f. 39. Fasciata. Var. app. sup. t. 12. er is Nimbosa app. sup. t. 13. f. 25. Pygmea app. sup. t. 12. f. 34. MYOCHAMA. Anomoides p. 48. sup. t. 12. f. 3. PANDORA. Obtusa p. 48. t. 3. f. 35. Rostrata p. 48. t. 5. f. 97. Oblonga p. 49. sup. t. 10. f. 46. Depressa p. 49. sup. t. 10. f. 47. Glacialis p. 49. sup. t. 10. f. 48. Flexuosa p. 49. sup. t. 10. f. 49. Unguiculus p. 49. sup. t. 10. f. 50. Trilineata p. 49. sup. t. 9. f. 32. Ceylanica p. 50. sup. t. 10. f. 45. SAXICAVA. Rugosa p. 50. t. 12. myv. f. 9. —var. Gallicana. p. 50. sup.t. 9.1 7.-5. Guerini p. 51. sup. t. 12. f. 2. Carditoides p.51. sup. t.12. f.53. Californica p. 51. sup. t. 12. f. 54. PETRICOLA. Ochroleuca p. 52. sup. t.1. TEL. £6. Semilamellata p. 52. sup. t. 11. f. 41. Lucinalis p. 52. t.8. f.73. Striata p. 52. sup. t. 11. f. 42. Costellata p. 52. sup. t. 11. f.43. Roccelaria p. 52. sup. t.11.f.44. Ruperella p. 52. sup. t. 11. f.45. Pholadiformis p. 52. sup. t. 13. £,,9. Costata p. 53. t. 8. f. 72. Nivea p. 53. t. 12. f. 16. Dactylus p. 53. sup. t. 18. f. 26. VENERUPIS. Perforans p. 54. t. 8. f. 108. Crenata p. 55. sup. t. 12. f. 58. Trus p. 54. t. 6. von. f. 21. Exotica p. 54. sup. t. 9. f. 29. Lajonkairii p. 55. sup. t. 12. f. 55. Monstrosa p. 55. t. 8. f. 112. SANGUINOLARIA. Occidens p. 55. t. 3. f. 29. Rosea p. 56. t. 3. f. 28. Nuttalii p. 56. sup. t. 12. f.56. Californiana p. 56. sup. t. 12. f. Bike Biradiata p. 56. t. 3. f. 26. Livida p. 56. sup. t. 11. f. 52. PSAMMOBIA. Rugosa p. 56. t. 8. f. 64. Ferroensis p. 57. t. 4. f. 36. Vespertina p. 57. t. 3. f. 27. Maculosa p. 57. sup. t. 11. f. 28. Cerulescens p. 57. t. 3. f. 31. Elongata p. 57. sup. t. 11. f. 46. Flavicans p.57. Var. sup. t. 1. f. 5. Squamosa p. 57. sup. t. 11. f.47. Cayennensis p.58.sup.t.11.f.48. Tellinella p. 58. sup. t. 11. f.11. Pulchella p. 58. t. 3. f. 6. Fragilis p. 58. sup. t. 11. f. 49. Rostrata p. 58. t. 3. sox. f. 22. Violacea p. 59. sup. t.11.f. 20. *Costata p. 59. sup. t. 11. f. 12. * TI have given the wrong habitat. It comes from Senegal. Lineolata p. 59. sup. t. 14. f. 1. Variegata p. 59. t. 3. f. 32. Castrensis p. 59. t. 3. f. 25. Pacifica p. 60. sup. t. 12. f. 59. Laskeyi p. 60. t. 4. f. 65. GALEOMNA. Turtoni p. 59. sup. t. 9. f. 41. Aurantia(PsammobiaA.) p. 58. sup. t. 9. f. 26. PSAMMOTZAA. Violacea p. 60. sup. t. 12. f. 60. Zonalis p. 60, sup. t. 11. f. 50. Pellucida p. 60. sup. t. 14. f. 26. Candida p. 60. sup. t. 13. f. 44. Tarentina p. 60. sup. t. 11. f. 56. Donacina p.€0. sup. t. 11. £.57. Rosea p. 60. t. 3. f. 23. TELLINA. Radiata p. 61. t. 4. f. 26. Semizonalis p. 61. sup. t. 11. f. 58. Maculosa p. 61. t. 3. f. 4. Virgata’ p. 61. t. 3. f. 3. Staurella p. 61. sup. t. 11. f. 31. Spengleri p. 62. t. 4. f. 35. Rostrata p. 62. t. 4. f. 28. Sulphurea p. 62. sup. t. 9. f. 9. Foliacea p. 62. t. 3. f. 20. Operculata p. 62. t. 4. f. 37. * Elegans p. 62. sup. t.1. f. 5. Margaritina p.63. sup. t. 13 f. 1. Albinella p. 63. sup. t. 14. f. 3. Strigosa p. 63. t. 4. f. 61. Planata’p! 63.\t. 3. £. 24. Punicea p. 63. t. 4. f. 64. Depressa p. 63. t. 4. f. 48. Flavescens p. 63. t. 4. f. 88. Pulchella p. 64. sup. t. 1. f. 4. Fabula p. 64. t. 3. f. 23. Tenuis p. 64. t. 3. f. 22. Exilis p. 64. sup. t. 13. f. 2. Donacina p. 64. t. 4. f. 31. Nitida p. 64. sup. t. 14. f. 4. Psammotella p. 65. sup. t. 14. f. 6. . Lantivyi p. 65. sup. t. 14. f. 5. Oudardi p. 65. sup. t. 14. f. 8. Clathrata p. 65. sup. t. 14. f. 12. Polita p. 65. sup. t. 9. f. 39. Tenera p. 65. sup. t. 9. f. 38. Tenta p. 65. sup. t. 14. f. 10. + Oblonga p. 65. t. 34. Alternata p. 66. sup. t. 14. f. 9. Chrystallina p. 66. t. 3. f. 10. Sulcata (Serrata erroneously p. 66.) t. 4. f. 63. ® Perfectly distinct from that very rare shell, the Crucigera of Lamarck. + Perfectly distinct from Psam- motella. LIST OF ILLUSTRATIONS. PLATE I. 1. Aspergillum Javanum 31. Pholas Truncata. 2, ————— Vaginiferum. 32. Crucigera. 3. ——- Novee Zealandiz. | 33. Campechensis. 4. Agglutinans. 34. Clausa. 5. Clavagella Aperta, (tube). 35. Crispata. 6. ———_—- —-——, (valve). 36. Clavata. 7 ito Blongata, (tube). SPs Ovum. 8. ———_—— —~——-, (valve). | 38. Falcata. 9, ————. Lata. 39. Acuminata. 10. Melitensis. 40. —— - Californica. Ly: Australis. 4] Papyracea. 12. — Balanorum. 42. —-— — (young). 13. Fistulana Clava. 43. — Tuberculata. : Gregata. ie : = Tabentla: eh ¢ Xylophaga Dorsalis. 16. Septaria Arenaria. 46. Globosa. 17. Teredo Navalis. 47. Gastrochzena Cuneiformis. 18 Palmulata. 48. ————— Mpytiloides. 19. Corniformis. 49, ——— Modiolina. 20. ——— (fide Blain- | 50. ——— Truncata. ville.) ol. Ovata. 21. —-—- Bipennata. 52. Solen Vagina. 22. ———- Nana. 53. Vaginoides. 23. magnified. 54. Corneus. 24. —-—— Malleolus. 55. —— Siliqua. 25. Pholas Dactylus. 56. —— Ensis. 26. Orientalis. oe: Linearis. 27. ——— Candida. 58. —— Scalprum. 28. Parva. | 59. Sloanii. 29 Silicula. | 60. Truncatus. 30, ——— Costata. | . Solen Guinensis. ; Brevis. . —— Thuelcha. — Pygmeus. . — Ambiguus. Cultellus. — Planus. —— Legumen. Dombei. 10. ——-- Javanicus. 11. ——- Caribeeus. 12. —— Coarctatus. 13. —— Strigilatus. CONAORWDH 14. Radiatus. 152 Politus. 16. —— Candidus. 17; Solidus. 18. Inflexus. 19. Orbiculatus. 20. ——-~- Costatus. 21 Medius. 22: ——— Maximus. 23, ——= Minimus. 24, —— Bidens. 25; Tenuis. 26. —-— Novaculina. 27. —— Californianus. 28. Acutidens. 29. Acuminatus. * The shell from which this figure is copied is, I find, perfectly distinct, though PLATE $i. 34. Panopea Aldrovandi. Bap Zelanica. 36. — Australis. 3/% Arctica. 38. Glycimeris Siliqua. 39. Mya Truncata. 40. —— Arenaria. 41. —— Cancellata. 42. Semistriata. 43. Anatina Lanterna. 44, —-—— Truncata. 45.>= Subrostrata. 46 Globulosa. 47. Periploma Trapezoides. 48. Argentaria. ~ 49. Planiuscula. 50.* Obtusa ? 51. Thracia Pubescens. 52, ——— Plicata. 4c Similis. 54, Conradi. 55. —-—— Convexa. 56. Corbuloides. O75 Curta. 38. . Glauconome Chinensis. - Rugosus. Solenella Norrisii. . Pholadomya Candida. Anatina ? Nicobarica. not at first sight to be distinguished from the remaining species of this genus. now describe, suggesting for it the name of Obtusa :—Very obtusely trapeziform, its outline totally devoid of angularities, very inequivalve, very fragile, dull yel- lowish white: very inequilateral, the sides rounded, edge of the longer posterior one obliquely and continuously united to the somewhat arcuated ventral ; anterior side very short, roughened by minute punctures, and very much narrowed by the sudden declivity of the dorsal edge ; anterior slope with minute and crowded concentric wrinkles, and bounded posteriorly in the more convex valve by a slightly impressed radiating hollow. 1}..14.—America. California? PLATE IIl. 1. Thracia Phaseolina. 32. Cyprinus. 2. Anatina! Membranacea. 33. Mactra Solidissima. 3. Globosa. 34. Spengleri. d. Elliptica. 35. ————NStriatella. B. Preetenuis. 36. Alata ; erroneously 6. Distorta. Striatula, 7. Papyracea. 37. ———— Glauca. 8. Leana. 38. —————Stultorum. 9: Elongata. | 39. — Grandis. 10, Myodora Brevis. 40. ————— Maculosa. 11. Ovalis. 4], ————-Nitida. 12. Pandoriformis. 42. ————— Glabrata. 13. Crassa. | 43, ————_—- Violacea. 14, Lyonsia Nitida. 44, ————Fasciata. 15 Hyalina. 45, ——— Turgida. 16, ————Elongata. 46, ————Plicataria. 17. ———Cuneata. 47, ——Rufescens. 18. Lutraria Solenoides. 48. Maculata. 19. Elliptica. | 49, ——-——Subplicata. 20. Rugosa. 50, ————Triangularis. 9) Egyptiaca, 51. ——— Lactea. 92. Ensis. 52, ———Ovalina. $3, Compressa. | 53, ————-Alba. “4, Tellinoides. 5A, Solida. 95. Tellina Angulata of Wood. | 55. —_———Squalida, 96. Lutraria Papyracea. 56, ———_—— Pellucida. 27, ————-Canaliculata. BE me LROR: 28 Complanata. 58, ——_—_— 99. —————Vitrea. 59, a Truncata. 30. Cottardi. 60, —_——_—-Subtruncata. 31, ———— Squamosa. The Work was discontinued in its present form owing to the difficulty of obtaining clear transfer impressions from such delicate engravings as the original copper-plates in the Index Testaceologicus. i ‘ PR SRE AE e Se OR Tet: SAO Ma Plate I . “ SS