66 AN ANNOTATED CATALOGUE 



a wide distribution, being found in nearly all of eastern 

 North America, and three of them are also circumpolar. 

 The wide geographical distribution of certain species of 

 mollusca, especially land forms among which it is so un- 

 common, points to a high antiquity for the group; and 

 in this instance, it is fully corroborated by palaeontological 

 evidence, in the occurrence of the subgenus Conulus, to 

 which Z. fulvus belongs, in the Carboniferous shales of 

 Nova Scotia. 



Family PHILOMYCID.E. 



Tebennophorus carolinensis Bosc. Common throughout 

 the state. 



Family HELICID^. 



Patula alternata Say. Abundant everywhere in damp 

 woodland ; often gregarious in hibernation. The loss in 

 the vicinity of Des Moines furnishes depauperate shells of 

 this species and also of P. strigosa with the red markings 

 still visible. A remarkable feature of the molluscan shells 

 occurring in this deposit throughout the state is a peculiar 

 chalky whiteness by which they are easily distinguishable 

 from "dead" shells of the same species now living in the 

 region. 



Patula perspecliva Say. Common at Iowa City and 

 elsewhere in eastern Iowa. 



Patula striatella Anthony. Abundant in the central 

 and eastern portions of the state. This species is also 

 very abundant in the loss at Des Moines. 



Microphysa pygmma Draparnaud. Polk, Johnson, Scott 

 counties : a minute but rather abundant species, formerly 

 more generally known under Morse's name Punctum mi- 

 nutissimum. 



Helicodiscus lineatus Say. Kather common in central 



