is.12.] Shell-Bearing Mollusca. 



Physa ampullaeea Gould. 



Rare. This seems distinet but is said to' 



Physa niagarensis Lea. 



Reported by Streator from Camp Creek i 

 ville but I have not seen the shells. Shells t 



size of hctrroxtropha. Very uniform in size 

 Genus Pfcmorta Guettaid. 

 P. trivdvis Say. 



Common but docs not develop its full size 

 P. bicarhiatus Say. 



Common. Also small. 

 P. catupanulatus Say. 



Not uncommon. 

 P. corpvlmtus Say. 



Doubtfully determined. 



Section Gyraulus Agass. 

 P. aZ6ws Mull. 

 P. defect us Say. 

 P. pomta Say. 

 P. c.mcntus Sav. 



All common. 



Section Segmentina Fleming 



