FAMILY 9. CARDIACEA. 103 



Chama antiquata, Linnaeus. 

 Venericardia sulcata, Payrandeau. 



PI. LXXIX. Fig. 4. (fossil.) 



Cardita imbricatus, Sowerby, Genera of Shells, No. 20. Deshayes, 



Enc. Meth. vers, vol. ii. p. 199. 

 Venus imbricata, Gmelin. 

 Venericardia imbricata, Lamarck. 



CYPRICARDIA, Lamarck. 



Testa sequivalvis, insequilateralis, oblique vel transversim elongata, latere 

 postico brevissimo. Dentes cardinales tres infra umbonem utrius- 

 que valvar impositi ; cum dente unico laterali subelongato, antice 

 porrecto. Impressio muscularis pallii indistincta. Ligamentum 

 externum. 



The shell of Cypricardia may be distinguished from that of Cardita by 

 its more oblong or elongated form, and lateral tooth ; De Blainville, how- 

 ever, is unwilling to distinguish the former but as a subgenus. Both 

 genera are intimately allied to the Chamacea, and might with equal pro- 

 priety be referred to that family : a transition may, nevertheless, be traced 

 from the Veneres to the Cardita with great accuracy. 



We may describe the shell of Cypricardia as being equivalve, inequi- 

 lateral, and obliquely or transversely elongated, with the posterior side 

 very short. There are three cardinal teeth placed beneath the umbo 

 in each valve, with a single, rather elongated, lateral tooth extending 

 along the anterior side. The palleal impression is indistinct, and the 

 ligament is external. 



