8 University of Michigan 



Zonitoidcs arborea (Say). Devils Lake, Court Lake, ]\Iau- 

 vaise Coulee. Sweetwater Lake, Upsilon Lake, Gravel Lake. 



Zonitoidcs uiiliitui (Morse). Devils Lake. Only two spec- 

 imens, identified by Dr. Sterki. 



Zonitoidcs niiniiscula (Binney). AJedora, Wllliston, Buford. 

 Evidently confined to the western part of the state. 



AgrioUmax cauipcstris (Say). Devils Lake, ^Nlauvaise 

 Coulee, Sweetwater Lake, Upsilon Lake. 



Pyraniidula cronkhitci anthonyi Pilsbry. Devils Lake, Court 

 Lake, Mauvaise Coulee, Sweetwater Lake, Upsilon Lake, 

 Gravel Lake, ]\Iedora. \\'illiston, Buford. An abundant spe- 

 cies, especially in the wooded area above the Mauvaise Coulee. 



Snccinca avara Say. Devils Lake, Stump Lake, Sheyenne 

 River. Only a few specimens, apparently distinct from gros- 

 vcrnorii. 



Snccinca ai'ara icrnicta Say. Big ^fission Lake, Sweet- 

 water Lake, Upsilon Lake. 



Snccinca grosvcrnorii Lea. Devils Lake, Fort Totten Lake. 

 Big Mission Lake, Mauvaise Coulee, Medora, Williston. This 

 was taken in many hot, exposed places, and seemed able to 

 withstand long periods of dry heat. 



Snccinca grosicnorii Lea, var. Devils Lake. Court Lake. 

 Fort Totten Lake, Upsilon Lake. Bottineau. "A very large 

 and obese race or form of S. grosvenorii. It . . . agrees in 

 color, texture and shape with certain lots from Colorado and 

 elsewhere, which connect with grosvenorii." (Pilsbry.) Of 

 these shells the largest measures 18:5 in altitude. The moist 

 undergrowth of SuUys Hill woods seemed a particularly fav- 

 orable habitat. 



Snccinca haydcni \\ . G. B. Big IMission Lake, Fort Totten 

 Lake, Sweetwater Lake, Sheyenne River. The largest speci- 



