32 



BIVALVES f AUDIU3I. 



Reticulata. 



Scobitina. 



Lactea. 



*Carnaria. 



*]Mniacvilata. 



Balthica. 



Pisiformis. 



Divaricata. 



Digitaria. 



* Cornea. 



*I^aciistris. 



Amnica. 



Papyracea. 



riinninalis. 



FUiniinea, 



Fluvialilis. 



Iberica. 



Adrialica. 



Siuuosa. 



Purpurata. 



Candida. 



Galiica. 



Senegalensis. 



Aiiguiosa. 



Polvffona. 



CARDIUM.— Cockle or Heart-shell. 



Animal— a Tctlii/s: Shell hivahe^ nearly equilateral, equi- 

 valve, fjenerally convex, longitudinally ribbed, striated, or 

 grooved, with a toothed margin; hinge with two teeth 

 near the heak, and a larger remote lateral one on each 

 sidCf each locking into the opposite. 



This genus, though not so numerous as the last, contains 

 gicat variety of structure and coloring. There are fifty- 

 two species. 



Tlie valves of the Cardium are for the most part of a 

 convex, swollen, or gibbous construction, and often 

 spherical : yet, in sonic instances, their form is elongated 



