HELIX. 83 



ted, more so than the outer lip, simple, but its upper por- 

 tion is reflexed and raised so as to form a marginal Avail 

 to the aperture, as it enters the shell, and produces a 

 slight fold -where it disappears AH thin the spire ; a broad, 

 thin callus covers the left margin, which is slightly de- 

 tached anteriorly, so as to form the rudiment of an 

 umbilicus. 



Length, half an inch ; breadth, one-third of an inch. 



GEOGRAPHICAL DISTRIBUTION. Found near Lake Con- 

 cordia, in Texas. 



REMARKS. At first view this shell might be mistaken 

 for Limnea columella. Its color and texture are like 

 S. amphibia, from which it differs chiefly in the slight 

 upturning of the edge of the columella lip, the faint re- 

 volving lines, and the ruddy apex. [G.] 



GENUS HELIX, AUCT. 



GENERIC CHARACTERS. 



ANIMAL. Body elongated, semi-cylindrical, tapering 

 to a point posteriorly, convex above, plane beneath, the 

 whole area forming a locomotive disk ; integument re- 

 titmlated by furrows surrounding numerous longitudinal 

 mucus-glands ; mantle simple, not extending beyond, 

 and accurately fitting to, the lip of the shell, into which 



