CONCHOLOGY. 55 



C. fuscata. C. Caroliniensis. 



C. violacea. C. fluminea. 



C. Ceylonica. C. Bengalensis. 



7. Genus Galathea. 

 Animal. As above. 



Shell. Equivalve, subtrigonal, covered with a greenish epi- 

 dermis ; the surface beneath is white, with several violet streaks 

 radiating from the summit to the margin ; two furrowed cardinal 

 teeth upon one valve, three upon the other, the middle one 

 being largest and callous ; muscular impressions double and 

 lateral. Inhabits the rivers of Ceylon. One species. 

 Galathea radiata. 



FAMILY X. 

 Cahdiacea. Five Genera. 

 1. Genus Cardiiim. 

 Jfiimal. Body somewhat inflated ; mantle edged with tenta- 

 cular cirrhi in all its inferior part ; tubes united, of moderate size, 

 and provided with cirrhi at the extremity ; mouth transverse, very 

 wide, with moderate labial appendages ; foot very large, cylindri- 

 cal, somewhat inclined anteriorly ; branchiae thick, rather small, 

 especially the external laminae : the internal united in all their 

 extent. 



Shell. Inflated, equivalve, sub-cordiform (when viewed ante- 

 riorly, usually costated from the apex to the circumference) ; 

 summits very evident, but slightly flexed to the front ; hinge com- 

 plex, similar, formed of two oblique, conical cardinal teeth, and 

 of two distant lateral teeth, upon each valve ; ligament dorsal, 

 posterior and very short. Inhabits the European seas. Fifty 

 living species. Fourteen fossil. 



Cardium indicum. Cardium costatum. 



C. asiaticum. C. ringens. 



C. fimbriatum. C. tennicostatum. 



C. aculeatum. C. pseudolima. 



