THE FAMILY NAIADES. 



13 



■en 



O 

 I— I 



"^ 



W 

 H 

 O 



I 

 O 





TRIANGULAR. 



ambiguus. Lea. 



Castalia ambigua. Lam. 

 Unio ambigua. Blain. Desh. 

 Mya ambigua. Wood. 



foliatus.* Hild. 



Unio flexuosa? Raf. 



Unio flexuGSus. Co;i., in text, Monograph, 



page 8. 

 Unio foliatus. Con., in plate 4, Monograph. 



OVAL. 



pliciferus. Lea. 



WIDE. 



I 



multistriatus. Lea. 



subtentus. Say. Con. 



Conradicus. Lea. 



my Memoir bears date May, 1830, while his is December, 1831. (See Tran- 

 sylvania Journal, Vol. V.) The reader will not after this be surprised to be 

 told that Mr. Say does not allow me, in his very incorrect " Synonymy," to 

 be the discoverer of a si?igle new species of Unio from our western waters ! ! 

 I may be allowed also to state, that I do not understand why he gives the 

 same name to two of his different numbers: thus, he calls No. 17, U. inter- 

 ruptiis, Rafin. ; and No. 47, U. interruptus, Say. The species are evidently 

 distinct. 



* The male oi foliatus is certainly a triangular shell — the female differs in 

 form very much, having a deep inflection on the posterior basal margin. It 

 may be doubted if this should be considered a plicate shell. I consider that 

 the folds of the growth, particularly in the male shells, requires it to be placed 

 there. 



