200 NATURAL HISTORY BULLETIN. 



species, also occurs on lower grounds, but both are more 

 common on drier slopes. Rare in the loess. 



**ZONITOIDES MINUSCULUS (Binn.) Pih. 



Common under stones, etc. on higher slopes, and under 

 sticks, leaves, etc. on lower grounds. Rare in the loess. 



b. Species of higher, more deeply shaded (often 

 mossy and rocky) banks and slopes, some- 

 times in deep woods. 



**Helicixa occulta Say. 



This species, though a prosobranch, is strictly terrestrial 

 in its habits. It is found living in but one locality, a 

 steep, rocky northern slope near Turkey creek, six miles 

 north of Iowa City, the locality in which it was first dis- 

 covered by the writer about twenty-two years ago. It is 

 quite abundant in this very restricted locality, being found 

 under stones and fallen leaves. It is very common in 

 the loess, and is found in nearly all the exposures. The 

 body-whorl of the fossil shell sometimes still contains the 

 operculum. 



The writer recently found this species (living) common 

 on the rocky slopes along Pine Hollow creek in Dubuque 

 county, and Little Turkey river and its small tributaries in 

 Clayton county, Iowa localities not hitherto reported. 



**Polygyra profunda (Say) Pih. 



Common under sticks, stones, leaves, etc. on higher 

 shaded slopes. It is found in but one loess-exposure in 

 this vicinity, but is very common in the loess of Natchez, 

 Miss. 



*Polygyra CLAUSA (Say) Pih. 



Widely distributed in deeper woods near Iowa City, but 

 nowhere common. As a fossil it is rare, occurring occa- 

 sionally in more southerly loess. None have been found at 

 Iowa City. 



