14 



SYNOPSIS OF 



in 

 o 



I— I 



H 

 O 



>^ 



Ph 



>^ 



I 



o 



M 



t3 

 O 



O 



o 



WIDE. 



acutissimus. Lea. 



Merchisonianus. Lea. 

 Unio Douglasiae? Gray. 



Grayanus. Lea. 



ARCUATE. 



ponderosus. Lea. 



Mya ponderosa. Solan. Dill. 

 Mya crassa. Wood. 



QUADRATE. 



lacrymosus.* Lea. 



asperrimus.t Lea. 

 Unio quadrulus. Say. 



fragrosus.J Con. 



* It is a matter of some doubt, if this be more than a beautiful variety of 

 asperrimus, (nobis.) Future observation must determine. Ferussac and 

 some other zoologists think it is distinct. 



j- Mr. Say supposed this to be the rtigosus, Barnes. Two specimens re- 

 ferred to by Mr. B. as rugosus were under my inspection, and proved to be — 

 the one a flat metanevra, Kafin., the other a plicatus, (Lesueur.) Mr. B, 

 in his reclamation, recognises his rugosus as U. Peruviayia, Lam., which 

 shell is undoubtedly the plicatus, (Lesueur and Say.) 



t This shell has been considered the female of asperrimus, (nobis,) but I 

 am, after the examination of many specimens, disposed to think it to be dis- 

 tinct. Some of our best western naturalists think it to be the true rugosus of 

 Barnes. 



