416 HELICID^. 



Strohila hh/rinthica, MoR'^E, Journ. Portl. Soc. i. 26, fi.ffs. 64-67 ; pi. 2, fi.2:s. a, b ; pi. 8, 

 fig. 68 (1864). — Tkyox, Am. Journ. Conch, ii. 259, pi. 4, fig. 44 (1866). 



Shell small, rounded-conical, apex obtuse ; spire elevated, whorls 

 six, separated by a well-marked suture, with conspicuous, oblique 

 lines or ridges at regular distances ; epidermis dark 

 brownish horn color ; aperture small ; outer lip thick- 

 ened, and somewhat reflected, often rose colored ; 

 inner lip with a long, raised line or tooth, which ap- 

 pears to revolve within the shell parallel to the sut- 

 ure, and sometimes a second nearer to the base, less 

 conspicuous, and terminating farther within the aper- 

 ture ; beneath flat, umbilical region impressed, and 

 . , . the umbilicus minute. Greatest diameter one tenth 



H. labyrinlhica. 



of an inch, height nearly as much. 



Animal has the head slate colored above, the tentacula quite 

 dark ; foot white as printing-paper, linear ; space between the four 

 tentacula and neck lighter colored. 



Found in various parts of this State, usually in the fissures of de- 

 caying wood, or under fragments of wood in moist places, or in beds 

 of decaying leaves. It inhabits a wide range of territory, having 

 been found as far distant as Missouri. It is not frequently found, 

 however, on account of its minuteness, and its dusky color. 



It inhabits all of Eastern North America.* Also occurs in the 

 post-pleiocene of the Mississippi Valley. 



It is readily distinguished from other species by the remarkable 

 raised lines revolving within the aperture. Usually, but one of 

 them exists ; but when both are present their parallel position gives 

 them a close resemblance to the track of a railroad. The oblique 

 plaiting of the whorls is very conspicuous, and renders the exterior 

 quite beautiful. The outer lip in fresh specimens has a rose colored 

 tint. The shell varies considerably in the elevation of the spire, 

 being sometimes much flattened, and again it has a pointed apex. 



Mr. Morse has lately given the following description of the inter- 

 nal lamin£e which characterize this species : — 



The shell has been described as having one revolving tooth within 

 the aperture, and sometimes a second one terminating farther within 

 the aperture. I have always found this second one constant, and also 



* Woochvard (Man. 384) refers an extinct English Eocene HeVix to this species. I have 

 seen no specimens of it, but cannot believe it identical. Mr. Bland writes me that he has 

 received from France a fossil shell under the name oi Helix lalnjnnthkida, apparently iden- 

 tical with our species. — W. G. B. 



