146 



iAND AND FRESH- WATER SHELLS OF N. A. [pakT I. 



xii. — Adams, Verrnout Molhisc.i, 159 (1842).— Pfeiffer, Mou. Hel. 

 Viv. I, 317.— W. G. BiNNEY, Ter. Moll. IV, 55. — DeKay, N. Y. Moll. 

 34, pi. ii, f. 17 (1843).— Mrs. Gray, Fig. of Moll. An. pi. cxci, f. 11, 

 nodescr. (from Bost. Journ.).— Morse, Anier. Nat. I, 99, f. 6,7 (1867). 

 — Not of Pfeiffer, vol. III. — Not of Chemnitz, ed. 2 (=roeineri). 

 } 

 From Ma^e'to Yh'ginia and to Ohio. It prefers mountainous 

 country. ■^' 



Readily distinguished from the allied species by the very 

 angular and broad reflection of the peristome. 



Fig. 250. 



Helix roenieri, Pfeiffer. — Shell with a narrow, or partially 

 covered umbilicus, sometimes imperforate, depressed, rather thin, closely 

 striated, rather transparent and smooth, horn-colored ; 

 spire slightly elevated ; suture lightly impressed ; 

 whirls five, ra her convex, increasing slowly, the last 

 one subcarinate at its periphery, scarcely descending ; 

 aperture lunar, oblique, generally slightly contracted 

 by a parietal denticle which obliquely enters the 

 mouth of the shell ; peristome white, thickened, the 

 upper portion hardly expanded, reflected below, and 

 at the columellar junction spreading into a thin, 

 partial covering to the umbilicus. Greater diam. 21, 

 lesser 18 ; height 10 mill. 



Helix roenieri, Pfeiffer in Roomer's Texas, 455 



(1S49) ; Zeitschr. f. Mai. 1848, 117.— Reeve, 



Con. Icon. no. 680. —W. G. Binxey, Terr. 



Moll. IV, 55. 



Helix dentifera, part, Pfeiffer, Mon. Hel. Viv. Ill, 269 ; in Chemxitz, ed. 



II, 331, pi. cxxxi, f. 1-3, not of Binney. 

 Mesodon roemeri, Tryon, Am. Journ. Conch. Ill, 43, pi. viii, f. 4 (1S67). 



Near New Braunfels, Texas ; Washington County and Colo- 

 rado River, Texas. 



This species is confounded by Pfeiffer with H. dentifei'a, an 

 authentic specimen of which he has not seen. It is quite a dis- 

 tinct species, and inhabits a distinct geographical region. It 

 may be distinguished from dentifera most readily by attention to 

 the following particulars : Its umbilicus is generally but partially- 

 covered, while dentifera is always imperforate; its color is lighter. 



Uelix roemeri. 



