234 Wisconsin Academy of Sciences, Arts and Letters. 
Sub-Class Euthyisteuea. 
Order PULMOHATA. 
Sub-Order BASOMMATOPIIORA. 
Eamilj Piiysidae. 
Genus Physa Draparnaud. 
24. Physa ancillaria warreniana Lea. 
Stations II 1 , III, IV 1 , V, VI, VII, VIII, IX, X, XII, 
XIII 2 , XIV 1 , XV, XVI. 
This Physa lives in either a protected bay or on an ex¬ 
posed shore; the protected bays, however, are frequently 
subject to rough conditions when the winds are from the 
unprotected side, which is often the case. Stations VIII 
andXII, both protected bays, produced the finest specimens. 
The normal habitat appears to be a sandy shore, but logs 
and other submerged objects are resorted to. 
Warreniana appears to be a race of ancillaria rather 
than of sayii . Specimens in Tomahawk Lake vary toward 
this species (ancillaria) in the wide aperature, low spire, 
and shouldered body whorl. The specimens secured were 
mostly of small size and were very solid. 
25. Physa gyrina Say. 
Station XXI. Swamp bordering the Wisconsin River. 
All of the specimens secured are immature. 
Genus Aplexa Fleming. 
26. Aplexa hypnorum (Linne), 
Station XXI. Typical, but not common. 
Family Ancylidae. 
Genus Ancylus Geoffrey. 
27. Ancylus parallelus Hal deman. 
Stations V, XIV 1 , XVII. This species occupied two 
habitats. At stations V and XIV it was found on the 
