Baker — The Molhiscan Fauna of the Dells of Wisconsin. 101 



III. Comparison of the material. 



A comparative study of the fauna of the different canons 

 and glens is of some interest. Several species, as Pyramidula 

 alternata, were abundant everywhere, while others, as Euco- 

 nulus fulvus and Cochlicopa lubrica, were found only in one 

 caiion or glen. It will be seen by comparing the annexed 

 table that the restricted species are Bifidaria corticaria, Philo- 

 mycuscarolinensis, Euconulus fulvus and Cochlicopa lubrica. 

 Strobilops aiBnis was the most abundant small mollusk, and 

 was found under almost every stick or log. The large snail, 

 Polygyra multilineata, seemed to be very rare, scarcely a dozen 

 specimens being found during the eight days of collecting. 



