204 NATURAL HISTORY BULLETIN. 



more common form, lives on wooded alluvial bottom-lands 

 which are not too dry, and may be found abundantly creep- 

 ing or hiding among the smaller plants, under fallen 

 leaves, etc. Four fossil specimens only were found in one 

 of the exposures at Iowa City, and it is rare in the loess of 

 the Missouri river in eastern Nebraska. The smaller form, 

 discussed under {d) , is much more common in the loess. 



*BlFIDARIA CONTRACTA {Say) Stcrki. 



Very common on rather low grounds, under logs, etc., 

 sometimes ascending to higher slopes. Absent from the 

 local loess and rare westward. It is more common in the 

 southern loess. 



BlFIDARIA PROCERA {Gld.) Stcrki. 



Only one local specimen was collected on rather low 

 ground. Westward this species is quite common in drier 

 situations, under sticks and leaves in clumps of bushes, 

 etc. None have yet been found in the loess. 



**YlTREA HAMMONIS {Strum.) PUs. 



This name is used for the species commonly known as 

 Zonites viridulus Mke. on the authority of Pilsbry. Bin- 

 ney refers Helix hammonis Strom, to Zouitcs fabricii Beck, 

 — a species from Greenland.* Our species is quite 

 common under logs, etc. on rather low, more or less 

 wooded, grounds. Rather rare in the local loess, but 

 more common westward. 



**PVRAMIDULA STRIATELLA (Allt/l.) PUs. 



Quite common on scantily timbered alluvial bottom- 

 lands, under logs, fallen leaves, etc. Also on higher 

 slopes. As a fossil it is very common, and is widely dis- 

 tributed, appearing almost universally in our northern 

 loess deposits. Fossil eggs, agreeing exactly with recent 

 eggs of this species, are also frequently found. 



* W. G. Binney: Terr. Air-Breath. Moll. U. S., vol. v, p. 127, 1878. 



