Descriptions of New Fluviatile Shells. 



essentially a striate shell. Upon the older specimens the folds 

 are nearly obsolete on the two lower whorls, being there coarsely 

 striate only. About twelve striae on the body whorl and six on 

 the penultimate ; more elevated in the centre, which renders 

 these whorls sub-angulated ; lines of growth strong, by reason 

 of which the two last whorls have quite a varicose appear- 

 ance. 



15. Ulelauia eliminata. 



, / 



Plate II. Fig. 15. 



T. elongato-conica, tenui, castanea ; spira gracili, elevata ; anfr. 8, 

 convexis transverse plicatis et spiraliter striatis, plicis striisque in anfr. 

 inferioribus evanescentibus : suturis impressis ; apertura parva, ovata r 

 purpurascente ; labro sinuoso; columella incurva, in sinum angustum 

 producta. 



Shell conic, thin, brownish ; spire slender, elevated ; whorls- 

 about 8, convex, with transverse folds and spiral striae, both 

 of which, however, disappear towards the lower portion of each 

 whorl, and are hardly visible on the last whorl ; sutures deeply 

 impressed ; aperture small, ovate, within translucent, exhibiting 

 the exterior coloring through its substance ; columella but little 

 rounded except near its base, where with the much curved lip- 

 it forms a sharp, narrow sinus. 



Length 0.80 inch (21 millim.). Diam. 0.24 inch (6 millim.). 



Length of aperture 0.26 inch (7 millim.). 



Breadth of do. 0.15 inch (4 millim.). 



Habitat. Kentucky, near Owenboro'. 

 My cab. Cab. Lye. Nat Hist., N. Y. 



Qls. This is a very slender and elevated species, resembling 

 in this respect M. comma Con., from which it differs very ma- 

 terially by the character of its folds and striae, which are more 

 decided, being nearly as prominent, though less distant, than 



MARCH, 1854. 2 ANN. jLyc. NAT. BIST., VOL. VI. 



