CORBICULA. 447 



Genus CORBICULA, Megerlo von Miihlfeldt, 



Shell orbicular, sub-cordate, solid, closed ; valves con- 

 centrically furrowed, covered with a thick, polished epi- 

 dermis. Hinge furnished with three primary teeth in each 

 valve, the front of right, and the hinder of left valve 

 smallest; lateral teeth elongate, compressed, striated across ; 

 ligament thick and prominent. Pallial line slightly sinuated. 



Ex. C. fluminea, Midler, pi. 110, fig. G, 6, a. 



The shells of this genus are orbicular, and covered with a 

 polished epidermis. Like the species of Cyrena, they are 

 found in the mud of rivers and estuaries in various parts of 

 the world ; America, China, and India harbouring examples. 

 Very numerous extinct forms occur in the Wealden of 

 Europe and the United States. 



Species of Corbicula. 



Africana, Krauss. fluviatilis, Midi. 



atnbigua, Desk. grandis, Desk. 



australis, Desk. iucrassata, Desh. 



Bengaleusis, Desh. Largillierti, Phil. 



Bensoni, Desh. limosa, Maton. 



Brasiliana, Desh. Malaccensis, Desh. 



Cashmiriensis, Desh. Moussoni, Desh. 



compressa, Mouss. Nepeanensis, Lesson. 



consobrina, Caillaud. nitens, Phil. 



convexa, Desh. obscura, Desh. 



cor, Lam. obsoleta, Desh. 



Cumingii, Desh. occidens, Bens. 



cuneata, Jonas. orientalis, Lam. 



fluminalis, Midi. ovalina, Desh. 



fluminea, Mull. Panormitana, Eicon. 



