484 Binney^s Monograph of the Helices 



ShelL Convexj elevated : epidermis^ brownish horn- 

 color : whorls, nearly six^ rounded, with crowded, ele- 

 vated; oblique striae : suture distinctly marked : aperture, 

 sub-triangular, contracted by the lip : lip white, reflect- 

 ed, with soQietimes a slight thickening on the inner side 

 near the base : umbilicus, closed ; umbilical region in- 

 dented. 



Extreme transverse diameter three fourths of an inch. 



X 



Geographical distribution. Inhabits the western 

 parts of Pennsylvania, and Ohio, and is probably found 

 in all the States bordering on the Ohio river. 



r 



Remarks. A very well marked species, distinguished 

 chiefly by its triangular mouth and elevated spire. The 

 volutfons are usually about six ; the shell is thin, and the 

 lip but narrowly reflected. Some individuals resemble 



s 



shell. 



ru 



usual 



with our helices. The color of all the thinner shells of 

 this genus appears darker when the animal is retracted, 

 and this species has often, in this situation,"a purplish 

 tinge, which is well represented in the plate. 



The animals of this, and of many other species, is 

 often overrun with great numbers of Acari, resembling 

 AcARus Kmdcum of Europe. There appears to be at 

 least two species of them. They are very minute, of a 

 flesh color, and move with great rapidity, frequently enter- 

 ing and coming out of the respiratory foramen. Their 

 presence does not seem to cause any uneasiness or even 

 to be felt by the snail. 



This shell varies in being more or less elevated : in 

 some individuals the spire is much flattened. It differs 

 greatly m size also, some perfect shells not attaining more 

 than one half of the size of others. Some persons have 



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