THE NAUTILUS. 91 



Fern Glen, St. Louis County. 



This is on the Merimac river, twenty-one miles from St. Louis. 

 The rock exposures are of Chouteau and Burlington limestone, but 

 none of the shells were found in abundance. 



Polygyra zaleta Binn. These cannot be distinguished from Ohio 

 specimens, and are of about the same size, up to 29 mm. diameter. 

 From other places in Missouri I have the P. zaleta ozarkensis of 19 

 mm. or less diameter, contrasting quite sharply with these. 



Polygyra thyroides Say. I found only dead shells, but doubt not 

 that on the low ground living ones could be found. 



Polygyra clausa Say. Dead shells not differing from others in 

 the state. 



Polygyra pennsylvanica Green. A single shell that looks like a 

 postpliocene fossil, but I think it is not such. I have found it in the 

 postpliocene at Providence, Boone county, and living as noted below. 



Polygyra elevata Say. Typical shells. 



Polygyra appressa Say. With rather heavy striation, and from 

 17^ to 25 mm. diameter. 



Polygyra fraudulenta Pils. Rather more numerous than any 

 other kind, and not found in Missouri except in localities noted on 

 this trip. 



Polygyra inflecta Say. Three dead shells. The umbilicus of two 

 was not covered. Similar specimens are noted from Shepard's 

 Mountain and from Rivermines. 



Polygyra hirsuta Say. A single shell. Pilsbry says that evi- 

 dence is wanting to show that this is found west of the Mississippi 

 and south of Kansas and Pettis County, Missouri whence I re- 

 ported it some years ago. The shell from this place and those 

 from two other places, hereafter noted are of this species; they 

 certainly are neither hlandiana nor uncifera. 



Polygyra fraterna Say. With quite small umbilicus. 



Polygyra dorfeuilliana Lea. This is the farthest north that I have 

 found this species. 



Pyramidula solitaria Say. A single shell, which like the penn- 

 sylvanica looks like a postpliocene fossil but I do not think it is such. 



Oircinaria concava Say. A number of dead shells up to 29 mm. 

 diameter. 



Bifidaria armifera Say. 



