148 HELICIDyE. 



apex ; aperture somewhat flattened, arcuated, contracted 

 bj a deep groove behind the lip ; lip white, narrow, a 

 little grooved on its face, reflected, extending on the 

 base to, and slightly contracting or wholly covering, the 

 umbilicus, its outer edge not projecting above the surface 

 of the whorl ; umbilicus open, deep, but not exhibiting 

 all the volutions, or partially covered by the extended 

 lip, or entirely closed ; base rounded, indented in the 

 region of the umbilicus, with a compressed, elongated 

 white tooth at the edge of the aperture. 



Greatest transverse diameter nearly one half of an 

 inch, ordinary size much less. 



GEOGKAPHICAL DISTRIBUTION. Inhabits the New 

 England States, in some parts of which it is very com- 

 mon, the States bordering upon the lakes, the Ohio River, 

 and the Mississippi as far south as Louisiana, and in Can- 

 ada. It will probably be found throughout the Middle 

 States, and in the hilly parts of the Southern States. 



REMARKS. The varieties of this shell present remark- 

 able differences in size, coloring, and in the form of 

 the umbilicus. The transverse diameter varies from one- 

 sixth to three-sixths of an inch, and the form from sub- 

 globular in small specimens to a very flattened shape in 

 the larger. The coloring exhibits every shade, from 

 light amber to dark chestnut. The whorls of some 

 revolve about the axis at such a distance as to leave a 

 deep and wide umbilicus ; while in others they are in 

 such near approximation as to permit only a small per- 



