156 



Venericardia. Shell equivalve, inequilateral, suborbicular, mostly with 

 longitudinal, radiating ribs. Two oblique cardinal teeth, standing the same 

 way. 



V. australis, V. Tankervillii, V. crassicosta, 10 fossil species. 



' flammea, (N. S.) 



CARDIACEA.— Five Genera. 



Cardinal teeth irregular, either in their form or in their situation; and in 

 general accompanied by one or two lateral teeth. 



Cardium. Shell equivalve, rather heart-shaped; the beaks prominent; 

 the internal margins of the valves dentated or plaited; hinge with four teeth in 

 each valve; the two cardinal approximate and oblique, articulating cross- 

 wise with the two in the other valve; and two rather distant, entering, lateral 

 teeth. 



costatum, 



Indicum, 



ringens, 



Asiaticum, 



tenuicostatum, 



fimbriatum, 



Brasilianum, 



apertum, 



papyraceum, 



bullatum, 



ciliare, 



echinatum, 



pseudolinia, 



C. aculeatum, 

 erinaceum, 

 tuberculatum, 

 isocardia, 

 muricatum, 

 angulatum, 

 marmoreum, 

 elongatum, 

 ventricosum, 

 rugosum, 

 sulcatum, 

 serratum, 



C. Isevigatum, 

 biradiatum, 

 seolicum, 

 pectinatum, 

 rusticum, 

 edule, 



Grcenlandicum, 

 latum, 

 crenulatum, 

 exiguum, 

 minutum, 

 roseum, 



C. scobinatum, 



' unedo, 



' medium, 



' fragum, 



' retusum, 



' tumoriferum, 



' hemicardium, 



' cardissa, 



' inversum, 



' Junoniae, 



' lineatum, 

 14 fossil species. 



Cardita. Shell free, regular, equivalve, inequilateral; hinge with two 



