Descriptions of New Fluviatile Shells. 



robust cylindrical form, combined with its pale sutural region ; 

 compared with J/ teres Lea, it is much less slender and turret- 

 ed, much more plicate, and the whorls are less inflated. M. 

 rufa is not folded, and is a more acutely elevated species. The 

 curve in the columella resembles that of M. columella Lea, but 

 that shell is much less elongated, has only six whorls, and is 

 destitute of distinct folds. 



17. II el a ilia incrassata. 



Plate II. Fig. 17. 



T. conica, glabra, crassa ; spira elevata ; anfr. 8-9, perconvexis, vix 

 biangulatis, ultimo spiraliter striato, in medio constricto ; suturis valde 

 impressis ; apertura ovata, intus rubescente ; columella reflexa, in sinum. 

 profundum producta. 



Shell conical, smooth, thick; spire elevated; whorls 8-9, 

 very convex, somewhat bi-angulated ; sutures deeply impressed; 

 body whorl striated, with a constriction about the middle, which 

 also extends to the penultimate whorl ; aperture ovate, within 

 reddish ; columella not indented, reflected, sinus deep. 



Length 1.12 inch (29 millim.). Diam. 0.45 inch (12 millim.). 



Length of aperture 0.37 inch (9 millim.). 



Breadth of do. 0.18 inch (4i millim.). 



Habitat. . 



My cabinet. 



Obs. Only one specimen has come under my notice, which, 

 however, is so unlike any other that I cannot hesitate to con- 

 sider it new. 



It is a thick, ponderous species, with narrow, convex or bi- 

 angulated whorls, faintly banded on the angulations. 



2* 



