HELIX. 905 



umbilicus very small ; umbilical region impressed. Great- 

 est transverse diameter five-eighths of an inch, usually 

 much less. 



GEOGRAPHICAL DISTRIBUTION. Inhabits all the "West- 

 ern States, where it is common. It has been noticed 

 also in Arkansas, and in the North-western Territory. 



REMARKS. This species varies in the greater or less 

 prominence of the spire, which sometimes is considerably 

 depressed, and at other times rises into a sub-conical 

 shape. The apex is, however, always obtuse, so that 

 the young shells might be supposed to belong to another 

 species, so different are they in shape from the mature 

 shell. When fully grown, there are seven whorls com- 

 plete, but usually the number does not much exceed six. 

 The epidermis is commonly shining, and the oblique strire 

 are numerous and distinct. The young shells are pellu- 

 cid. The base of the shell within the aperture is thick- 

 ened with a very white callus, which is seen from with- 

 out. The umbilicus is very small, and sometimes quite 

 closed. The lip, at its junction with the base of the 

 shell, is slightly reflected. //. Wardiana of Lea, is 

 undoubtedly the young of this species. The distinction 

 in the animal, noticed by Dr. Ward, was afterwards 

 ascertained by him to be merely accidental. 



Mr. Say's name should be retained for this shell, as 

 his description was published several months before Fd- 

 russac's name appeared, and several years in advance of 

 his figure. 



