Notes on the MoUuscan Fauna of Northern Illinois. 321 



For C. pyramidata (James), see page 152, April number of this 

 Journal. 



Cyclonema varicosa — (Hall). 



Shell turbinate ; height and greatest breadth about equal. Spire 

 consisting of about four volutions, which increase rapidly in size, the 

 last one extremely ventricose ; the lower side somewhat flattened near 

 the upper part of the columella, which is straight and thickened. 

 Aperture as wide as high, transversely semi-oval. 



Surface marked by strong revolving striae, about three of which on 

 the upper volutions and four or more on the last volution become more 

 strongly developed, and give a subcarinate form to the volutions ; 

 between these the striie are fewer and unequal. The revolving striaj 

 are crossed b}' finer lines of growth, which on the upper volutions are 

 nearly uniform, but toward the aperture become crowded, unequal, 

 and sublamellose. 



This species resembles the Cyclonema percarinata, but is more ventri- 

 cose, with different surface markings. It is larger, more ventricose, and 

 very differently marked from C. bilix. It is regarded by some, how- 

 ever, as merely a variety of C. biliv. It is found on the hills back of 

 Cincinnati, but is not common. 



Cyclonema percarinata — (Hall). 



Somewhat obtusely conical, ventricose ; spire short, obtuse ; volu- 

 tions three or four, rounded, marked by numerous spiral carina, which 

 are crossed by vertical or undulating striee ; aperture not distinctly 

 visible, but apparently it is broadly oval or rounded ; umbilicus none. 



It is distinguished by the numerous spiral, elevated ridges or carina?, 

 which mark the surface. 



It is found at Cincinnati, from low water-mark to about 250 feet 

 above, though it is not abundant at any known locality. 



Notes on the Mollnscan Fauna of Northern Illinois. — By W. W. 



Calkins. 



The author hopes to publish at some future time a complete mono- 

 graph of all the mollusk species of Illinois, giving a figure of each, and 

 embracing in the work such new facts as he may obtain in regard to 



