AMERICAN JOURNAL 



DESCRIPTIONS OP NEW FRESH-WATER SHELLS 

 OF THE UNITED STATES. 



BY GEORGE W. TRYOX, JR. 



STEEP0MATIDJ5. 



1. AxGiTREMA Wheatleyi, Trjon. — t. 2, £ 1. 



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

 conical, sharp pointed, suture 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, iialf 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. 

 HaUtat.—E\]^ River, at Winchester, Tenn., (C. M. Wheat- 

 ley.) 



My Cabinet. Cabinet of Charles M. Wheatley. 



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

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

 appearance more like an obese variety of A. verrucosa, Raf., 

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

 tubercles. The Avell-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 



