AMERICAN JOURNAL 



DESCRIPTIONS OP NEW FRESH-WATER SHELLS 

 OP THE UNITED STATES. 



BY GEORGE W. TRYOM", JR. 



STREPOMATID.E. 



1. Axgitrema Wheatleyi, Try on. — t. 2, £ 1. 



Description. — Shell conoidal, inflated, rather thin; spire 

 conical, sharp pointed, snture not much impressed; whorls 

 about 6, those of the spire flattened, the body whorl large, 

 rather flattened above the somewhat angled periphery, convex 

 below, and somewhat attenuate at the base; the periphery is 

 ornamented with a single prominent row of slightly com- 

 pressed tubercles, and above is rugosely wrinkled, with a 

 tendency towards tuberculation ; aperture large, sub-rhom- 

 boidal, half the length of the shell, somewhat attenuate below, 

 columella nearly perpendicular, a little twisted. Bright horn- 

 color, with four broad, equidistant brown bands. 



Dimensions. — Length 25 mill., diam. 16 mill. 



Habitat. — Elk River, at Winchester, Tenn., (C. M. Wheat- 

 ley.) 



My Cabinet. Cabinet of Charles M. Wheatley. 



Observations. — This species is much more inflated, and has 

 more numerous tubercles than A. Duttoniana, Lea; it is in 

 appea-rance more like an obese variety of A. verrucosa, Raf., 

 but that species is heavier in texture, and has several rows of 

 tubercles. The well-developed tubercles and inferiorly con- 

 tracted aperture will readily distinguish this species from Li- 

 thasia fuliginosa, Lea. 



2. Pleurocera bicinctum, Tryon. — t. 2, f. 2. 



Description. — Shell elevated conical, somewhat cylindrical, 

 thick, smooth and shining; spire elevated, obtuse, suture dis- 

 tinctly but not deeply impressed; whorls about 6, somewhat 

 flattened, the last with an angular periphery, which is cari- 

 nate, and a second carina, less distinct, below it; lines of 



