120 THE NAUTILUS. 



Punctum pygmceum (Drap.). Thief River Falls. 

 Succinea retusa Lea. White Earth Lake, var. Thief River Falls. 

 Succinea oralis Say. Thief River Falls, var. Minneapolis. 

 Succinea avara Say. Thief River Falls, Cannon Lake. 

 Succinea avara vermeta Say. White Earth Lake. 

 Strobilops virgo (Piis.). Thief River Falls, White Earth Lake. 

 Bifidaria contracta (Say). Thief River Falls, White Earth Lake. 

 Bifidaria pentodon (Say). Thief River Falls. 

 Bifidaria tappaniana (C. B. Adams). White Earth Lake. 

 Bifidaria hohingeri Sterki. White Earth Lake. 

 Cochlicopa lubrica (Miiller). Thief River Falls. Also a form 

 which seems to be C. I. morsea/ia Dolierty. 



Vollonia cosUita (Miillei). Thief River Falls, White Earth Lake. 

 Carychium exile canadense Clapp. Tliief River Falls, White 

 Earth Lake. 



Lampsilis hileola Lam. Thief River Falls. 

 Anodonta kennicotti Lea. Thief River Falls. 

 Vnio gibbosus Barnes. Thief River Falls. 

 Quadriila Idchrymosa Lea. Thief River Falls. 

 SphcBiium simile Say. Lake Harriett. 

 Sphceriiim occidentals Prime. Thief River Falls. 

 Musculium jayanum Prime, Thief River Falls. 

 Pisidium sp. Thief River Falls. 



Gampeloma subsolidani Anthony. Mississippi River, Minneapolis. 

 Canipeloma riifum Hald. Lake Harriett. 

 Gampeloma milesii Lea. Thief River Falls. 

 Vahata sincera daniehi Walker. Cannon Lake. 

 Valvuta tricariiiata Say. Cannon Lake. 

 Valvata tricarinata simplex Gld. Cannon Lake. 

 Aynnicola limosa Say. Var. Cannon Lake. 

 Pliysa ancillaria Say. Lake Harriett. 

 Physa gyrina Say. Lake Harriett. 

 P/iysa gyrina liildrelhiana Lea. Thief River Falls. 

 Physa gyrina oleacea Tryon. White Earth Lake. 

 Aplexa hypnorum (Linn.). Thief River Falls, Halma. 

 Lymncea stagnalis appressa Say. Thief River Falls, White Earth 

 Lake, Halma, Lake Harriett. 



Lymncea stagnalis var. Lake Harriett. 



Lymncea ohrussa Say. Thief River Falls, Cannon Lake. 



