62 Notes on Species of Corbiculadce. 



cate, and somewhat inflated. The anterior side is rounded and 

 the posterior somewhat attenuated. The beaks are small, acute, 

 they curve inwardly and are approximate. The hinge is very 

 slightly curved, narrow and delicate ; the cardinal teeth are 

 very small, the lateral teeth are long, narrow, and slight. The 

 interior is whitish-lilac with a tinge of light pale brown on the 

 basal margin. The sulci are very nearly obsolete ; they become 

 more distinct, however, and less regular as they approach the 

 inferior portion of the shell. The epidermis is of a soiled yellow- 

 ish color, violet upon the beaks and with occasional spots of 

 grey, and somewhat polished on the margins. 



This species is different from all others of the genus ; its out- 

 line is more like that of a Batissa or Cyrena, and it comes very 

 near a species of Cyrena from the Basin of Paris, the Cyrena 

 compressa. The texture of the valves is remarkably delicate 

 proportionately to their size. 



Monsieur Morelet, to whose kindness I am indebted for my 

 specimens of Coroimla lutea, observes that this species is found 

 very abundantly, and that it is used by the natives as an article 

 of food. 



6. Corbicula difGcilis, nov. spec. 



Corbieula diffieilis, Prime in Htt. Cat. 4. 1865. 



C. testa ovato-trigona, insequilaterali, in medio inflata, latere antic© 

 producto, postieo brevi, subtruncato ; umbonibus pavvulis, obtusis, incur- 

 vis, oppositis, apice dermdato; valvis intus violaceis, ad margines satu- 

 ratioribus ; cardine rotundato ; epidermide fusco-virente,. subnitente ves- 

 tita ; regulariter sulcata. 



Long. 26 ; lat. 24 ; diam. 15 mill. 



Hah. — Africa Septentrionalis ? Collect. Deshayes et Prime. 



The shell is rounded, trigonal, inequilateral. The anterior 

 side is produced and the posterior is snbtruncated. The beaks 

 are small, obtuse, they curve inwardly, and when denuded show 



