MERETRIX. 



423 



astartoides, Beck. 



cor, Sow. 



elegautina, Lam. 



gallina, Linn. 



hiantina, Lam. 



Japonica, Gmel. 



rnesodesrna, Quoy and Gaim. 



pallida, Turt. 



Perouii, Lam. 



Philippii, Desk. 

 polita, Quoy and Gaim. 

 recens, Chem. 

 regularis, Desk. 

 rimularis, Lam. 

 scalariua, Lam. 

 striata, Chem. 

 striatula, Da Costa. 

 tristis, Lam. 



Sub-gen. makcia, H. and A. Adams. 

 Shell with the surface of the valves smooth. 



ainbigua, Desk. 

 Ceylonensis, Soiv. 

 Crepliui, Dkr. 

 exalbida, Chem. 

 fumigata, Sow. 

 interrupta, Koch. 

 Kochii, Phil. 

 Kraussii, Desh. 

 leuticularis, Sow. 



marmorata, Lam. 

 obovalis, Desh. 

 piuguis, Chem. 

 quadraugularis, Adams and 



Reeve. 

 radiata, Chem. 

 undulosa, Lam. 

 ustulata, Desh. 



Genus MERETRIX, Lamarck. 



Mantle-margins plain; siphons united half-way. 



Shell ovately suh-triangular, thick, smooth ; margins of 

 valves simple, entire. Hinge thickened, tri-dentate, the 

 anterior lateral tooth contiguous, heneath the lunule, the 

 hinder lateral teeth crenulated. Pallial line simple, or pos- 

 teriorly slightly sinuated. 



Syn. Cytherea, Lamarck. Nympha, Martini. 



Ex. M. impudica, Lamarck, pi. 107, fig. 6, 6, a. 



The shell in this genus is solid, usually more or less 

 transversely ohlong, with slightly prominent heaks ; the 



