POTAMOPHILA. 



Galathea. — jBrw^\ Encycl. method, pi. 250. f. 1. a. b. c. 



TESTA crassa, transversa^ aeqiiivalvis^ subtrigona^ 

 epiderme vireiite induta. Dentes cardiiiales 

 crassi ; duo in valva dextra, basi conniventes; 

 tres in altera^, in triangulum dispositis^ inter- 

 medio minore^ distincto. Dentes laterales in- 

 distinctissimi^ remotiusculi. Ligamentum exter- 

 num^ breve^ prominens, turgidum. Ni/mphce 

 prominulae. Impressiones 7nusculares in utraque 

 valva duagj versus basis testae excavati. 



We regret that we are obliged to change the name of this 

 Genus ; this necessity arises from the circumstance of La- 

 marck's having employed the name of Galathea twice, in 

 one instance to denote a Genus of Crustacea, and in the 

 other for the shell in question ; and we find Galathea, 

 already adopted by others, as the Generic name of the 

 Crustaceous animal, for which it claims also the right of 

 prior application, having been adopted by Lamarck from 

 Fabricius. We have, therefore, applied the term Potamo- 

 phila to the shell, which will designate the predilection of 

 its animal inhabitant for River water in preference to that 

 of the Sea. 



In comparing our specimens with the Generic Cha- 

 racter and description given by Lamarck, we find we cannot 

 comprehend several expressions which he has made use of ; 

 the first, when speaking of the three teeth in the left valve, 

 he says ^"L^intermediaire avancee^grosse et c«//ew5e," whereas, 

 we find the intermediate of the three to be the smallest, 

 and the least prominent ; the second, " Dents cardinales 

 silloncesj^ whereas, we find jjo grooves on the cardinal 



