202 NATURAL HISTORY BULLETIN. 



a fossil, but is one of the rarer species of the local loess. 



*Circinaria concava {Say) Pits. 



Widely distributed on shaded, especially rocky, slopes, 

 but not gregarious. It is not found in the local loess, 

 but is quite common southward. It is one of the common 

 fossils at Natchez, Miss. 



**CONULUS FULVUS {Drap.) Mull. 



Not uncommon on shaded slopes in moss, and under 

 sticks, leaves, etc. Fossil shells are not rare, and as a rule 

 are better developed than the modern specimens. 



*Zonitoides arboreus {Say) Sterki. 



Very common, usually under logs in high or low places, 

 and not uncommonly in comparatively open woods. It 

 can not yet be reported from the local loess, but has been 

 found by Prof. Savage in the loess of Henry county, Iowa, 

 and it is not rare in the western loess. 



**Pyramidula alternata {Say) Pi/s. 



Locally common, usually on higher, deeply-shaded slopes 

 under logs, stones, leaves, etc. Not common in the loess 

 at Iowa City. 



**P\-RAMIDULA PERSPECTIVA {Say) Pils. 



Common on shaded banks, etc. under decaying logs. 

 This species is not generally distributed in the loess, though 

 it is very common at Natchez, Miss. At Iowa City it 

 occurs rather abundantly in but one exposure. 



**Helicodiscus lineatus (Say) Morse. 



Scattered specimens are not infrequent. They are 

 usually found in deeper shade under sticks and logs. 

 Fossil shells are quite rare. 



*PUNCTUM PYGMiGUM {Drap.) Biiiu . 



This minute shell is easily overlooked, but is quite 

 common under sticks and fallen bark on northerly shaded 



