DIM Y AIR A. 125 



Distiug^uished from the Cardita, with which they are closely allied in form, 

 by having three teetli beneath the apices, like the genus Venus, in addition 

 to the callous lengthened tooth or ridge. 



Cypricardia Guinaica. — The Guinea Cypricardia. Plate 

 XVI. fig. 13- Transversely oblong, oblique, angulated, white, 

 and covered with decussated stricB ; compressed before, and the 

 apex rounded ; yellowish-white. Two inches long. Inhabits 

 the coast of Guinea. 



Genus 17.— CARDITA — Lamarck. 



Generic Character. — Shell free, regular, equivalve, inequi- 

 lateral ; hinge with two unequal teeth ; primary tooth short, 

 straight, placed under the umbo ; the other oblique^ marginal, 

 and elongated. 



Some of the species require minute attention to the teeth, to distinguish 

 them from the Venericardia. 



Cardita sulcata. — The Furrowed Cardita. Plate XVI. 

 fig. 15. Subcordate, white, tessellated with brown ; having 

 longitudinal, convex transversely striated ribs ; posterior depres- 

 sion heart-shaped. One inch long. Inhabits the Mediterra- 



Genus 18.— CARDIUM.— XinwffMs. 



Generic Character. — Equivalve, subcordate ; beaks promi- 

 nent ; the interior margins of the valves denticulated or plicated ; 

 hinge with four teeth in both valves ; with two approximate 

 primary oblique teeth, mutually inserted and crossing each 

 other ; two lateral remote teeth. 



Section * Shells with no particular angle at the umbones, and the anterior 

 side at least as large as the posterior. ** With the umbones carinated or 

 angular, the posterior side oflen much larger than the anterior. 



Cardium edule. — The Edible Cardium. Plate XVI. fig. 

 14. With about twenty-six depressed ribs, and transverse ob- 

 solete scales ; outside yellowish-white, and inside white ; beaks 

 protuberant. One to one and a half inch long. Inhabits the 

 European seas. 



l3 



