144 TESTACEOUS MOLLUSCA. 



ribs longitudinally striated, the posterior ones subcrenated, the 

 anterior rngulose, the interstices dotted. \^^. 



C. Planicostatum. &0W. Z. P. \S3:i.— Reeve, t. 77./. 25.— 

 C. I. J". 25. Subcordate, palish, variegated with brown and 

 fulvous ; posteriorly rounded, anteriox-ly 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, if.. If. — Closehj resemhling Me- 

 dium. 



C. DoNACiFORME. Schrcetev. Ein. 3. p. 68. t. 7 . f. 14.— 

 Bruff.p. 214.— TF. t. 5./. 38.— Gmel. 3247.— D. p. 114.— Ch. 

 f. 1(55. — 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. f • . 1 • — Much resemhlin<j Donax 

 Cardioides. 



C. SUBRETUSUM. Sow. JuH. Z. P. 1840.— C I. f. 24.— 

 Reeve, t. 86.,/". 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. 



1 .■5_ _9_ 



^TO • • 10* 



CARDITA. 



Shell free, regular, equivalve, inequilateral ; hinge with two tin- 

 equal teeth. ; primary tooth short, direct, placed tinder the umbo ; 

 the other ohliqiie, marginal, and produced under the corselet. 

 * Suhcordiform or oval. 



C. Sulcata. Lam,.\. — Philipni.p. 53. Chama Antiquata. 

 Lin. U38.— D.J). 2\5.—Poli.t. 23./. 11 to 19.— 67/,./. 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 Ajar. Drug. Diet. pAO(j. — Lam. 2. — Adans. Seneg. t. 16. 

 /. 2. — Chama 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 crow^ded with rows of scale- 



