TRIBE CARDIACKA. 129 



VENERICARDIA. 



Equicalve, inequilateral, suhorhiadar, generally with longitudinal, 

 radiating ribs : hinge nith two oblique teeth in each valve, turned, 

 in the same direction. 



V. AusTRALis. Lam. Sow. Tank. — Ast. t. 78. f. 12, 3, 4. — 

 Cham A A. W. S. t. 2. f. A. 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, ij'c. 



Y. Megastropha. Gray. Ann. Phil. 25. vignette j). 138. 

 Obliquely heart-shaped, thick, white variegated with rufous, with 

 convex wrinkled ribs : hinge margin very thick. 1 . — New Holland ? 



V. Crassicosta. 8om. Tank. Cat. Heai-t-shaped, tumid, 

 anteriorly angulated, with twenty-two thick depressed ribs which 

 are angulated at their sides, irregularly cvenated, variegated witli 

 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, sid>cordate ; beaks proijiinent ; the interior margins of 

 the valves denticidated or plicated ; hinge with four teeth in both 

 valves ; with two approximate j^rimary oblique teeth, vwfually 

 inserted and crossing each other ; two lateral ronote teeth. 



* No particular angle on the beaks, and the anterior side at least 

 as large as the 2>osterior. 



C. CosTATUM. Lin. 1\2\.—D.p. lOO.—Lam.l.— TFood. G. 

 C. t. 56.f. 1.— TF. t. 5./. 34.— List. t. 327. f \G4.— Ch.f. 151, 

 2.—E. t. 292. f. 1. a7id 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..3|. — Guinea and Senegal.— (From the straightness of the 

 hinge-margin the shell seems auriculated.) 



C. Indicum. 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, 



