HELIX. 419 



Stenotrema monodon, Morsk, Journ. Portl. Soc. i. 10, fig. 13 ; pi. 2, fiif. 2 ; pi. 4, fig. It 

 (1864). — TuYON, Am. Journ. Conch, iii. 56, pi. 9, figs. 18-20 (1867). 



Var. FRATERNA. 



Helix fraU-rna, Say, Long's Exped. ii. 257, pi. 15, fig. 3 ; Binney's ed. 30, pi. 74, fig. 3. 



— Mrs. Gray, Fig. Moll. An. pt. 193, fig. 5, no descr. — Binney, Bost. Journ. iii. 



363, pi. 10, fig. 2, not of Wood. 

 Helix monodon, De Kay, 1. c. part, pi. 3. fig. 21, a, 6 (1843). — Wood, Index, Suppl. pi. 



7, fig. 15. 

 Helix conivxn, Chemnitz, cd. 2, i. 86, part; — var. Reeve, Con. Icon. 1. c. — ^ ; Ffeif- 



FER, Mon. Hel. Viv. i. 420. 

 Hdix moncdon /*, Pfeiffer, 1. c. iv. 320. 



Var. LEAH. 



Helix convexa y, Pfetffer, 1. c. ; var. Chemnitz, 1. c. pi. 66, figs. 24, 25. 



Helix monodon y, Pfeiffer, Mon. Hel. Viv. iv. 320. — part Binney, Terr. Moll. pi. 41, 



central figures. 

 Helix Lcaii, Ward, MS. teste Binney. 

 Lister, Syn. Conch, pi. 93, fig. 94. 



Shell slightly convex ; whorls five or six, narrow, diminishing 

 very gradually in breadth from the outer whorl to the apex, 

 marked with very fine lines of growth, and covered with a ^'^^' " 

 dark russet or chestnut colored epidermis, which is beset 

 with very minute, hair-like projections ; aperture contracted 

 by a deep groove behind the lip; lip white, narrow, reflexcd, 

 a little grooved on its face, extending on the base to the 

 umbilicus and slightly contracting it, and its outer edge 

 not projecting beyond the surface of the whorl ; umbilicus ^/i","""' 

 deep, not exhibiting all the volutions, partially covered by 

 the lip ; base rounded, very much excavated at the umbilical region, 

 with a compressed, elongated white tooth at the edge of the aper- 

 ture. Greatest diameter nearl}^ half an inch. 



Animal yellowish-brown, darker on the head and tentacula. Foot 

 narrow, cylindrical, half as long again as the diameter of the shell, 

 terminating in a point. Eyes black. 



Found in the middle and western parts of this State, sometimes 

 in forests with other species, but more commonly on the hill-side 

 pastures under stones, where other species rarely occur. Two indi- 

 viduals are commonly found together. It is also found in the North- 

 ern and Northwestern States ; indeed, through all of Eastern North 

 America, and through Canada. Also in the post-pleiocene of the 

 Mississippi Valley. 



The varieties of this shell present remarkable differences in size, 

 coloring, and in the form of the umbilicus. The transverse diam- 



