PHYSA. 167 
Subgenus ISIDORA, Ehrenberg. 
46. PHYSA INTEGER, Haid. 
Monog. p. 33, t. 4, f 7—8. 
Physa Niagarensis, Lea.—Plate 8, fig. 5. 
I cannot detect the slightest difference 
between Mr. Lea’s species and the previously 
published integer. It is a very common shell 
in the Great Lakes and St. Lawrence River, 
but becomes rarer to the southward, and has 
not been reported south of Tennessee. 
47. PHYSA DISTORTUS, Haldeman. 
Monog. p. 35, t. 5, f. 1—3. 
Subgenus AMERIA, H. Adams. 
(83) 
