8 University of Michigan 



30. Phxsa intcgra Hald. var. — Schoolcraft: Most of the 

 specimens from this county are distinguished from the typical 

 form by the presence within the aperture of a heavy reddish 

 varix, and by the more shouldered and less expanded char- 

 acter of the whorls. They were found on sand and grass in 

 Bear Creek and on sticks in the Manistique River. 



31. PJivsa aplcctoidcs Sterki. — Schoolcraft: Several speci- 

 mens were collected on rotten leaves in a wooded swamp. The 

 first record for this species was made in Ohio by Dr. Sterki ; 

 the second (first for Michigan) on Isle Royale by Dr. Walker. 

 This is the second Michigan record and adds a connecting link 

 for the two localities. 



32. Physa sp. — Schoolcraft, Chippewa. In this division 

 are placed all the shells too young for specific identification. 



33. Aplcxa hypnornm (L.). — Schoolcraft: In a wooded 

 pond, the bed of a brook, and a slough, several specimens were 

 taken. 



34. Planorhis trivolvis Say. — Schoolcraft: From dead 

 leaves in a pond, and from submerged brush in a glacial lake 

 surrounded by a cranberry marsh. Alger : A good series of 

 specimens was obtained in Whitefish Lake and in Silver Lake. 

 The typical form grades into the following variety. 



35. Planorhis trivolvis hinncyi Tryon. — Alger: From 

 Whitefish Lake. The intergradation of this form with the 

 typical trivolvis seems again to bear out the opinion of Dr. 

 Walker that binncyi is a variety, and not a distinct species 

 (Baker, p. 277). One specimen agrees in surface malleation 

 with the shell figured by W. G. Binney (p. 115, fig. 193) as P. 

 corpulentus and noted as "a curiously indented form from the 

 west coast." The same specimen, which is the largest of the 

 lot, measures as follows: greatest diameter 27.25 mm., lesser 



