lo University of Michigan 



rallonia yracilicusta i-ieinhard. Devils Lake, Mauvaise 

 Coulee, Sweetwater Lake, Stump Lake, Upsilon Lake, Me- 

 dora, Buford, Williston. Abundant everywhere in the woods. 

 Sterki comments on the absence of / '. piilcliclla, costata and 

 parvula. Many bags of forest debris sorted in the laboratory 

 failed to discover any of these species. Several other curious 

 gaps are noticeable also: no Gastrocopta pcntodon, tappaniana, 

 corticaria, Pyyramidiila alternata, nor 1 1 clicodiscns parallcJns. 



I'alloiila pcrspcctiva Sterki. Devils Lake, Stump Lake, 

 Mauvaise Coulee, Medora, Buford. Not so numerous as (jra- 

 cilicosfa, but occurring with it. 



Carvcliiitiii e.vifjituni (Sayj. Court Lake. Three specimens. 



Cavychiitiii exile canadcnsc Clapp. Court Lake, Upsilon 

 Lake. 



Lymncca caperala Say. Devils Lake, Big Mission Lake, 

 Mauvaise Coulee, ditch pond near (iarske, Medora, Buford, 

 Williston. The shells show considerable variation in propor- 

 tions ; some have long spires and short apertures, others are 

 more rounded with shorter spires. 



Lymncca biiliinoides cocker clli Pils. (!v Ferr. Medora. A 

 few immature si)ecimens from drift wer-s so identified by 

 Walker. 



Lymncca dalli Baker. Court Lake, Lake at Warwick, 'i'aken 

 from grass and marshy ground. 



Lymncca obnissa cxigiia Lea. Ujjsilon Lake, (jravel Lake. 



Lymncca paluslrls Miiller. Devils Lake, Court Lake, Fort 

 Totten Lake, liig Mission Lake, Mauvaise Coulee, Wood 

 Lake, Lac aux Morts and nearby ditches and marshes, Sweet- 

 water Lake, Stump Lake pond, Sheyenne River, Upsilon Lake, 

 Gravel Lake, Lake Metagoshe, Carpenter Lake, Bottineau, 

 Buford, Williston. The shells from ditches near Lac aux 



