1 907 J Notes on Some Fresh Water Shells 239 



NOTES ON SOME FRESH WATER SHELLS FROM 



MANITOBA. 



By J. F. Whiteaves. 



In June, 1906, Professor Macoun collected a few fresh water 

 shells at two localities in Manitoba. The species represented in 

 these collections are as follows, those to which an asterisk is pre- 

 fixed having been kindly determined by Dr. V. Sterki. 



A. Frjm a small lake four miles and a half dice west of Hamiota. 



Pelegypoda. 



* Sphoerium (Musculium) allied to S. securis, Prime. 

 Several specimens. 



* Pisidium Roperi, Sterki. 

 Several specimens. 



Gasteropoda. 



Segmentina (Plaiiorbula) Christyi, Dall. 



Six adult and perfect, but dead specimens. This species, 

 which was first described and figured by Dall in 

 1905, in volume xiii of the " Harriman Alaska 

 Expedition " Reports, was based upon seven speci- 

 mens, from "High Bluff, Manitoba, (R. Miller 

 Christy) " and " Fort Smith, Mackenzie River (E. 

 A. Preble)." in the United States National Museum. 

 The small lake from which Professor Macoun col- 

 lected his specimens, is about 104 miles west of 

 High Bluff. 



Planorbis ( Torquis) parvus, Say. 

 Ten specimens. 



Physa gyrhia ? Say. 



Four very young specimens. 



