TRIBE CARDIACEA. 129 
VENERICARDIA. 
Equivalve, inequilateral, suborbicular, generally mith longitudinal, 
radiating ribs: hinge with two oblique teeth in each valve, turned 
in the same direction. 
V. Austrauis. Lam. Sow. Tank.—Ast. t. 78. f. 12, 3, 4.— 
Cuama A, JW. S. t.2. f.4. Rounded and obtusely cordate, 
posteriorly short and rounded, anteriorly angulated at the ventral 
edge which is strongly arcuated ; thick, convex, whitish, transversely 
variegated with chesnut brown on its numerous narrow angulated 
and crenulated ribs: inside stained with brown anteriorly, margin 
coarsely toothed. 1.—Australia, Sc. 
V. MeeastropHa. Gray. Ann. Phil. 25. vignette p. 138. 
Obliquely heart-shaped, thick, white variegated with rufous, with 
convex wrinkled ribs: hinge margin very thick. 1.—New Holland ? 
V. Crassitcosta. Sow. Tank. Cat. Heart-shaped, tumid, 
anteriorly angulated, with twenty-two thick depressed ribs which 
are angulated at their sides, irregularly crenated, variegated with 
pink orange crimson and dark brown : inside white. 
TRIBE CARDIACEA. 
Primary teeth irregular, either in form or situation ; and 
accompanied by one or two lateral teeth for the most part. 
CARDIUM. 
Equivalve, subcordate ; beaks prominent ; the interior margins of 
the valves denticulated or plicated ; hinge with four teeth in both 
alves; with two approximate primary oblique teeth, mutually 
inserted and crossing each other ; two lateral remote teeth. 
* No particular angle on the beaks, and the anterior side at least 
as large as the posterior. 
C. Costatum. Jin. 1121.—D. p. 109.—Lam.1.—Wood. G. 
Ox6 [561 FV 8 6.50 NBA Tiist. 4) 3272 EON Ff. V5, 
2.—H. t. 292. f. 1. and t. 293. f.1. Gibbous, sub-globose, thin, 
nearly equivalve, with high keeled membranaceous longitudinal 
white ribs, the interstices reddish tawny ; anterior side gaping ; 
within white, with grooves corresponding to the exterior ribs. 
3..33.—Guinea and Senegal.—(Krom the straightness of the 
hinge-margin the shell seems auriculated.) 
C. Inpicum. Lam. 2.—C. I. f. 46. Heart-shaped, tumid, 
sub-equilateral, with obtuse ribs, which at the margin of the an- 
terior end are covered with spines resembling the teeth of a saw, 
of the posterior with rather distant trumpet-like scales; white, 
K 
