FAMILY 7. NYMPHACEA. 77 



The Psammobire, which serve to connect the genera Sanguinolaria and 

 Tellina, are chiefly characterized by their shell being always more or less 

 angular at one end, with the cardinal teeth short and mostly bifid. The 

 species which constitute the genus Psammotaa of Lamarck were separated 

 from his Psammobise on account of an assumed deficiency of the cardinal 

 teeth, but this was purely accidental*; they were therefore reunited by 

 De Blainville, Sowerby and others, the first of whom proposed the new 

 title of Psammocola. 



The shell of Psammobia is described as being transverse, oblong, or 

 ovately oblong, gaping a little at the sides, and covered with a thin 

 horny epidermis. The hinge consists of two short bifid teeth in one 

 valve, and one in the other, with an external ligament. 



The palleal impression exhibits a very large sinus. 



Examples. 



PI. LIII. Fig. 1. 



Psammobia rugosa, Sowerby, Genera of Shells, No. 35. 

 Venus dejlorata, Gmelin. 

 Sanguinolaria rugosa, Lamarck. 

 Psammocola rugosa, De Blainville. 



PL LIII. Fig. 2. 



Psammobia violacea, Sowerby, Genera of Shells, No. 35. 

 Psammotcea violacea, Lamarck. 

 Psammocola violacea, De Blainville. 



PI. LIII. Fig. 3. 



Psammobia cerulescens, Lamarck, Anim. sans vert., new edit., vol. vi. 



p. 174. Sowerby, Genera of Shells, No. 35. 

 Psammocola carulescens , De Blainville. 



* Sowerby asserts that the Psammotace were characterized from broken specimens : this is 

 most probable ; Lamarck himself, indeed, pronounces them to be " Psammobies d&gtn&ries" 



