THE NAUTILUS. 17 



Polygyra fraterna Say. The same may be said of this as of the 

 last. From both places. 



Polygyra monodon Rack. From both places. 



Polygyra hirsuta Say. Sparingly at both places. The ordinary 

 size is of 7 mm. diameter, but one from Providence is of 9 mm. and 

 somewhat differing from the smaller ones in other respects. 



Succinea ovalis Say. A single one found at Lupus. 



Gastrodonta ligera Say. A single one was found at Lupus. At 

 some places in Boone county the living ones are plenty. 



Helicina occulla Say. In my report of the Shells of Missouri this 

 was given as Helicina orbiculata tropica. It is rather scarce on both 

 sides of the river, and has never been found living in the State. 



Vitrea indentata Say. From Lupus. 



Vitrea hammonis Strom. Some young shells from Lupus were 

 probably of this species. 



Zonitoides minusculus Binne. From Lupus. 



Zonitoides milium. From Lupus. 



Bifidaria armifera Say. At Lupus. 



Bifidaria contracta Say. These and other minute shells were not 

 found imbedded in the dirt, but in clearing the larger Polygyra of 

 the dirt that filled them a number of small shells were found. These 

 and some smaller Pupillidce that have not been identified, were found 

 at Lupus. 



Pyramidula solitaria Say. This at Providence is perhaps as 

 abundant as P. appressa, but at Lupus it is rare and somewhat 

 smaller. 



Pyramidula alternata Say. At Providence they are of good size 

 and not plenty ; at Lupus rare and smaller. 



Pyramidula perspectiva Say. A single specimen was found at 

 each place. 



Helicodiscus parallelus Say. From Lupus. 



Garychium exile H. C. Lea. From Lupus. 



An idea of the comparative number of the species may be had 

 from the results of a walk along the railroad for three miles on the 

 Providence side, during which hundreds of shells were picked up or 

 seen, among which were only four prof undo, one pennsylvanica, one 

 clausa, and one alternata, while soltiaria and appressa were abund- 

 ant, and elevata next in abundance. 



