144 TESTACEOUS MOLLUSCA. 
ribs longitudinally striated, the posterior ones subcrenated, the 
anterior rugulose, the interstices dotted. 8”. 
C. Puanicostatum. 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. CO. America. 13..12.—Closely resembling Me- 
dium. 
C. Donactrorme. Schroeter. Ein. 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. %..1.—Zuch resembling Donax 
Cardiotdes. 
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 
cavity close under the umbones, a slight callus within it. 
ee 
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. Suucata. Lam. 1.—Philippi. p. 53. CHama 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. 14.— Mediter- 
ranean. 
C. Asar. Brug. Dict. p.406.—Lam. 2.—Adans. Seneg. t. 16. 
f.2.—Cuama A. D. 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- 
