Baker — The Molluscan Fauna of McGregor, Iowa. 257 



Campeloma subsolidum Anthony. 

 Common. 



Family Physidae. 



Physa gyeina Say. 



Common in creek near Pictured Rocks. 



Family Pupidae. 



Strobilops virgo Pilsbry. 

 Common. 



BlFIDARIA ARMIFERA Say. 



Only one specimen collected. 



Family Succineidae. 



Succinea retusa Lea. 

 Common. 



Family Helicidae. 



POLYGYRA CLAUSA Say. 



Common. 



Polygyra thyroides Say. 

 Apparently not common. 



Polygyra multilineata Say. 

 Not common. 



Polygyra profunda Say. 

 Not common. 



Polygyra hirsuta Say. 



Only two dead specimens found. 



Polygyra monodon Var. fraterna Say. 

 Fairly common. 



Family Circinariidae. 



Circinaria concava Say. 

 Fairly common. 



