Family STREPOMATIDAE, Ilaldeman. 

 STllEFOMA, Raf. 



Subgenus TRYPANOSTOMA, Lea. 



T. siihnlare, />ea. Aldricli?'" Lewis; Robinson. 



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



Subgenus GONIOUASIS, Lea. 



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



(Lewis). 

 G. (lepygis, Say. Lake Champlain (Adams) ; [querie, Uvescens f] 



G. Haldeiuani, Tryon. St. Lawrence Riv. (Tryon) ; [querie, livescens?'\ 



G. gomnia, DeKay. Mud Creek, Onondaga Co. ; [querie, livesc€ns?'\ 



G» Vil'g'iuicaj Gmclin. Aldricli ; Lewis ; Robinson. Say mentions mV- 



ginica as occurring in Niagara River. May 

 he not have had before him one of the two 

 species of Trypanostoma described by Lea 1 



Subgenus ANCULOSA, Say. 



A. carinata, Brvg. Homer, Cortland county (Dr. Green) ; Oneonta 



(Yager). 



COIS'CHIFERA LAMELLIBRANCHIATA. 



Family CORBICULADAE. 



SPHAEKIUM, Scopoli. 



S. simile, Say. Aldrich ; Ingalls ; Lewis ; Robinson. 



S. solidulum, Prime. Lewis. 



S. striatimim, ia?rt. Aldrich; Ingalls; Lewis; Robinson. 



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



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

 him at Troy. His record embraces the following species : 



" Melania virginica, Gmelin.'''' 



" Melania elevata, >Say." 



"Melania subularis? i«a." 



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

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



