﻿UNITED STATES. 95 



The description of soft parts is made from specimens from Macon ; while the exte- 

 rior enveloping hard parts are described and figured from Buckhead Creek specimens. 



Remarks. — Quite a number were received from Mr. Plant, in alcohol. The species 

 belongs to the group of which angustatus may be considered the type. It is not so 

 wide, but thinner and more inflated than that shell. It is very closely allied to 

 Maconensis, (nobis,) but differs in the umbonial slope, not being so angular, and in 

 having a blunt truncate posterior margin well defined by two angles. It is also 

 thinner in the substance of the shell, and the epidermis is not so dark and is not 

 quite so smooth. There is a marked difference between the specimens from the two 

 localities, and they may be found, when better observed, to be really distinct species. 



