104 Trans. Acad. Sci. of St. Louis. 



Family Pupidae. 



Bifid aria corticaria Say. 



This species was very abundant in old logs on the sides of 

 Artists' Glen. All of the specimens collected had a single 

 tooth on the parietal wall. They were most abundant under 

 "started' bark, a single piece of bark often concealing a 

 dozen specimens. 



Strobilops affinis Pilsbry. 



This was the most abundant small snail and was found 

 everywhere. 



Strobilops virgo Pilsbry. 



Apparently quite rare and seemingly restricted to Cold 

 Water Canon and Witches Gulch. While trying to identify 

 these small shells the writer hit upon the plan of moistening 

 the base of the shell and holding it near the light, so that the 

 number and position of the small lamellae within the last 

 whorl could be distinctly seen. This has proven quite suc- 

 cessful and does away with breaking the shell to see the 

 lamellae. 



Family Endodontidae. 



Helicodiscus lineatus Say. 



Found only in Cold Water Canon and at Cold Spring, and 

 not common at either place. The few specimens collected 

 were very large. 



Pyramidula alternata Say. 



Abundant everywhere. The jelly-like eggs of this species 

 were very common. In many places the young snails, about 

 3 mm. in diameter, had hatched and were actively crawling 

 about. 



Pyramidula striatella Anthony. 



Abundant in Cold Water Canon, Witches Gulch, the Lower 

 Dells and at Cold Spring. 



