TRIBE CARDIACEA. 143 
€. Carpissa. Lin. 1121.—D. p. 110.—Lam. 45.—Ch. f. 
143, 4.—W.t. 5. f. 53.—H. t. 293. f. 3. (Young. C. Dro- 
neum, C. I. f. 1.) Heart-shaped, with the valves compressed but 
convex on both sides, white, thin, with the ribs granulated, (the 
posterior ones being the more prominent), the keel toothed and 
the umbones approximated, with a small cordiform depression under 
them; the anterior side convex near the hinge, becoming flattish 
towards the margin.— From keel to keel, 24.—Indian Ocean. 
C. Monstrosum. Chem. f. 149, 150.— Gmel. 3253.—D. p. 
112.—C. Inversum. Lam. 46.—H. t. 295. f. 1. Heart-shaped 
with the valves compressed, the anterior side convex and 
lightly grooved, the posterior concave with subgranular ribs, and 
the lower extremity of the valves curled up towards the beaks ; 
white with yellowish spots and chevrons disposed the whole length 
of the keel, which is armed with very small distant points: um- 
bones approximated from keel to keel 14.— Nicobar Isles. 
C. Humanum. Chem. f. 145, 6.—D. p.111.—W. t. 5. f. 
54.—C. Junonrex. Lum. 47.—E. t. 294. f. 20. Heart-shaped, 
the valves compressed, and the keel nearly unarmed; purplish red 
or white with rosy spots, the anterior side concave and lightly 
grooved, the posterior ribbed and somewhat granular : umbones 
approximated. — Variety. Ch. f. 147,8.—C. Roseum. D.p.112. 
—Variety. E. t. 294. f. 2.—From keel to heel, 2.—Indian 
Ocean. 
C. Linratum. Lam. 48.—C. I. f. 23. Heart-shaped, keeled, 
obliquely truncated anteriorly, very glabrous, thin, rayed with 
white and fulvous, with transverse undulating striz ; within reddish 
near the beaks and indications of ribs towards the margin. -1.— 
America. 
C. Imsricatum. Sow. Jun. Z. P. 1840.—C. J. f.48. Thick, 
ventricose, rounded posteriorly, anteriorly subquadrangular and 
angulated, white within, orange with purple spots; the twenty-eight 
ribs, (of which the nineteen ‘posterior are strong aly imbricated, the 
extreme anterior subangulated and smoothish,) are angulated and 
rough with vaulted imbrications near the umbones, near the ventral 
margin obtuse. 153,.. 14.—Smwan River.— Like Medium in shape. 
C. Fornicatum. Sow. Jun. Z. P.1840.—C. I. f. 50. Sub- 
quadrangular, angulated anteriorly, rounded posteriorly, white with 
purple spots ; within orange spotted with reddish purple at the 
margins: with thirty-five ribs, the twenty-three posterior ones 
biangulated, imbricated with most minute pointed crenulations at 
the sides. 1..1.—Like Medium in shape. 
C. Branevutatum. Brod. § Sow. Z. f. 4.—C. I. fo 2.— 
Reeve. t. 73. f. 2.—Beech. Zool. t. 42. f. 5.—C. I. f. 2. Turgid, 
obliquely subcordate, anteriorly biangulated, posteriorly rounded ; 
marbled with whitish, greyish, purple, and chesnut ; the radiating 
