100 Descriptions of New Fluviatile Shells. 



Shell ovate-conic, smooth, olivaceous, thick; spire obtusely 

 elevated, decollate ; whorls 3-4, remaining flat or concave ; 

 sutures distinct ; penultimate and body whorl with a broad, 

 deep, concave excavation, their edges being elevated into an 

 obtuse carina, tipped with a lighter color ; lines of growth very 

 strong ; aperture not large, ovate, reddish within ; columella 

 regularly curved, thickened by a deposit of calcareous matter, 

 purplish and white, indented near its base, without any sinus. 



Length (of an eroded example) 0.84 inch (21 millim.). 



Diam. ( do. do. ) 0.44 inch (11 millim.). 



Length of aperture 0.40 inch (10 millim.). 



Breadth of do. 0.22 inch (5J millim.). 



Habitat. — Alabama. 

 My cabinet. 



Obs. — An unadorned species of a dull olive color, not easily 

 confounded with any of its congeners. Differs from M. fusi- 

 formis Lea by its broad, more elevated spire, its purple mouth, 

 unadorned with bands, but above all, by the peculiar excava- 

 tion on the lower whorls, which is so peculiar as to distinguish 

 this species from all others. 



19. Tlelania casta. 



riate II. Fig. 19. 



T. conica, plerumque glabra, crassa ; spira obtuse elevata ; anfr. 6-7, 

 subplanis, ultimo subangulato superne glabro, interne liris quinis exilibus 

 cincto ; suturis impresses ; apertura elongato-ovata, intus albida, sub- 

 margaritacea ; columella subrecta, in sinum modicum producta. 



Shell conical, nearly smooth, thick ; spire obtusely elevated ; 

 whorls 6-7, nearly Hat ; sutures well impressed ; upper whorls 

 smooth, or only modified by the lines of growth, which are 

 coarse and distinct; body whorl with five prominent striae 



