THE NAUTILUS. 189 



Bythinia tentaculata L. The recent discovery of this species at 

 Holland, Michigan, by Dr. DeCamp was noticed in the Nautilus 

 for October, 1891. I am indebted to him for specimens. 



Somatogyrm isogonm Say. Cited by Miles and Currier. Stimp- 

 son's anatomical studies of this species for his " Researches upon the 

 Hydrobiinse" were made from Michigan specimens. (Loc. cit., p. 

 22). DeCamp cited it in his catalogue on Currier's authority but 

 writes : " I do not believe that it exists in this State. Have for many 

 years examined the ground where Currier said he found the spec- 

 imens sent Stimpson, but have never found anything but young of 

 Campeloma decisa." 



Amnicola porata Say. Common all over the State. A. pallida 

 Hald. and llmosa Say, which are cited in different lists as distinct, 

 are now I believe generally considered forms of this species. 



A. cincinnatiensis Anth. Not as common as the preceding spec- 

 imens, but ranges over the whole State. 



A. decisa Hald. Cited by DeCamp. 



A. grana Say. Common in the southern part of the State. 



A. lustrica Pils. Common and somewhat variable. The late Dr. 

 James Lewis, many years ago, characterized specimens from the 

 Huron river at Ann Arbor as " largest I have ever seen." 



Bythinella atlenuata Hald. Cited by DeCamp, to whom I am 

 indebted for specimens from Grand Rapids. 



B. teiiuijjes Coup. Cited by DeCamp, who writes me : " I sent 

 living specimens to Tryon and he sanctions their identity." 



B. Binneyi Tryon. Cited by DeCamp. 



B. Nichlinana Lea. Cited by DeCamp. 



B. obtusa Lea. River Rouge, Wayne County. Also cited by 

 DeCamp from Kent County. 



Poviatiopsis lapidaria Say. Common in the southern part of the 

 State. 



P. cincinnatiensis Lea. Cited by Beecher in the list of Ann 

 Arbor shells. I have received specimens from Petersburg, Monroe 

 County collected by Mr. Jerome Tronibly. 



Pleurocera subulare Lea. Southern part of the State. Common. 



P. subulare intenstim Anth. Collected by Dr. Leach in Mono 

 Lake, Muskegon. Cited also by DeCamp. 



