98 



LAND AND FRESH-WATER SHELLS OF N. A. [pART IV. 



Fis- 185. 



between them ; spire not remarkably elevated, but acute, of a rather 

 convex outline ; whorls 8-9, somewhat convex, and with sutures not 

 prominent, but channelled; body- whorls with about four carina;, the 

 lowest one being indistinct; aperture small, subrhomboidal, with two 

 bands in the interior, distant from each other and from the edge of 

 the outer lip; outer lip much twisted, auger-like, causing the sinus, 

 which is small, to curve backwards. 



Diameter, -28 inch (7 millim.) ; length, -CO inch (15 



milllm.). Length of aperture, -25 inch (G millim.) ; breadth 



of aperture, -13 inch (3 millim.). 

 Habitat. — Tennessee. 

 Observations. — A beautiful little shell, of a singularly 



bright, lively appearance ; the colors are well contrasted, 



very distinct, and the prominent carina? add to the general 

 effect. On the upper whorls, but one band is visible, the lower one 

 being concealed, or nearly so, l)y the revolutions of the spire. It 

 cannot well be compared witli any other species. — Anthony. 



Mr. Antlioii3'''s type is figured. The following is Mr. Lea's 

 description of 



Trijpanostoma curtatum. — Shell smooth, pyramidal, yellowish, thick; 

 whorls seven, flattened, the last one impressed ; aperture rhomboidal, 

 whitish within; outer lip acute, expanded, very sinuous; columella 

 thickened, bent in, and very much twisted. 



Operculum ovate, dark brown, with polar point 

 near the base on the left. 



Habitat. — Powell's River, near Cumberland 

 Gap, East Tennessee. 



Diameter, -41 ; length, -75 inch. 



Observations. — Quite a number of this species 

 were sent to me by Major Lyon. It is a short thick species, with a 

 well-characterized aperture, the columella being much thickened, 

 drawn back and twisted. It is allied to T. pumilum and minor 

 (nobis), but differs from both in having the sides flattened and being 

 angular about the middle of the body-whorl. Very few of curtatum 

 are banded, while all I have seen of the above two species are banded, 

 and the epidermis polished. The aperture is about one-third the 

 Icucth of the shell. — Lea. 



Fig. 18G. Fig. 187. 



