OP coNcnoLOOY. 243 



Patulinj^. Shell moderately thick, translucent to opaque, 

 epidermis opaquely colored, sometimes banded or striped in 

 the largo species, striate or ribbed, discoidal, planospiral, or 

 spire a little globoscly elevated. Umbilicus wide. Mouth 

 not toothed, (lamellately toothed in one species only. 



Linrjual dentition. — Uncini bidentate, laterals either long or 

 square, bidentatc or tridentate. 



VITRININ^. 



Genera. 



1. ViTRiXA, Drap. Shell very thin, polished, transparent, 



small, consisting of two or three depressed whorls, ra- 

 pidly increasing. Aperture very large, oblique, lunate. 

 Columellur margin a little inflated. Axis imperforate. 

 Nearly covering the contracted animal. 



2. BiXNEYA, Cooper. Shell ear-shaped, nearly flat, whorls 



two, laet whorl enormously expanded. One-third as 

 long as the animal, which it does not half cover when 

 contracted. 

 Much more depressed, with a larger proportionate aperture 

 than Vitrina. 



VITRINA, Drap. 

 1. Vitrina limpida, Gould. 



Plate 3, figure 1. 

 Globosely depressed, whorls 2|, scarcely convex, suture 

 very slightly canaliculate; plane of aperture very oblique. Co- 

 lorless. 



Diam. G mill. 



Maine to Michigan, and Northward. 



2. Vitrina Angelicse, Beck. 



Plate 3, figure 3. 

 Globoscly depressed, whorls 3|, suture crenulated, spire, 

 small, somewhat prominent; aperture lunately oval, oblique. 

 Color greanish yellow. 

 Diam. 6, height, 3-5 mill. 



Greenland. 



Moi-a globose, with one more whorl and more prominent 

 spire than No, 1, 



