139 



Family STREPOMATIDAE, Haldeman. 

 STKEPOMA, Raf. 



Subgenus TRYPANOSTOMA, Lea. 



T. subulare, Ze«. Aldricli?!^ Lewis ; Robinson. 



T. pallidum^ Lea. Niagara River (Lea). 



Subgenus GONIOBASIS, Lea. 



G. livescens, Menke. Niagara River (Robinson) ; Central New York 



(Lewis). 

 G. depyg-iSj Say. Lake Champlain (Adams) ; [querie, liveseens .?] 



G. Haldeinani, Tryon. St. Lawrence Riv. (Tryon); [querie, Imescensl^ 



G. gemma. Be Kay. Mud Creek, Onondaga Co. ; [querie, livescens^\ 



G. Virginicaj G'wc'^i/i. Aldricb ; Lewis ; Robinson. Say mentions mr- 



ginica as occurring in Niagara River. May 

 lie not bave had before him one of the two 

 species of Trypanostoma described by Lea ? 



Subgenus ANCULOSA, Say. 



A. carinata, Brug. Homer, Cortland county (Dr. Green) ; Oneouta 



(Yager). 



CONCHIFERA LaMELLIBRANCHIATA. 



Family CORBICULADAE. 



SPHAERIUM, Scopoli. 



S. simile, ^«y. Aldrich; Ingalls ; Lewis; Robinson. 



S. solidiilum, Prime. Lewis. 



S. striatiuum. Lam. Aldrich ; Ingalls ; Lewis ; Robinson. 



S. rliomboideum, Say. Ingalls ; Lewis ; Robinson. 



16 Aldrich seems to have been in doubt as to the identity of some of the species observed by 

 him at Troy. His record embraces the following species : 



" Melania virginica, GhTielin." 



" Melania elevata, Say." 



"Melania subularis? Lea." 



It is reasonable to suppose that the species he called " elevata" may have been that which is 

 tabulated here as G. liveseens, Menke. The other two species are probably correctly surmised. 



