148 HELICID^. 



apex ; aperture somewhat flattened, arcuated, contracted 

 by 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 

 aU the volutions, or partially covered by the extended 

 lip, or entu'ely 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. 



Geographical 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 difierences in size, coloring, and m the form of 

 the umbihcus. The transverse diameter varies from one- 

 sixth to thi'ee-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 

 hght amber to dark chestnut. The whorls of some 

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

 deep and wide umbihcus ; while in others they are in 

 such near approximation as to permit only a small per- 



