52 LAND AND FRESH WATER MOLLUSKS 



Helix cooperi Binney, Proc. Acad. Nat, Sci. Phila., for 1858, p. 118; Land 



and Fw. Sh. N. Am., i, p. 78, figs. 132-137, 1869. 

 Helix haydeni GhBB, Am. Joum. Conch., v, p. 24, pi. viii, fig. i, 1869. 

 Anguispira bruneri Avic^Y, La Nature, iii, p. 468, Sept., 1881. 

 Oreohelix strigosa Pilsbry, Nautilus, xvii, No. 11, p. 131, footnote, 1904. 



Range. — Type at Spokane, Wash., also in the Rocky Mountain 

 region from northern Mexico to and somewhat beyond the 49th parallel 

 westward from the Lake of the Woods. 



Var. cooperi., Lake of the Woods, and westward to the Rockies 

 near the 49th parallel. 



Var. j/a«/o«/ Dall (1905). Thirty-three miles southeast of Medi- 

 cine Hat, Assiniboia, near top of Cypress Hills, altitude 4,700 feet; 

 latitude about 49° 30', west longitude 1 10° 10'. 



The variety stantoni is dwarfed, measuring in maximum diameter 

 lO.o, minimum 8.5, and height 8.0 mm., with about five whorls, a 

 peripheral brown band with a narrower one above and sometimes 

 others on the base, the remainder ashy, rudely incrementally striate, 

 with rounded periphery and deep narrow (i mm.) umbilicus. It is 

 very similar to some varieties of the European H. virgata Da Costa. 

 Eight specimens were collected by Dr. T. W. Stanton in 1903. 



A large number of names, varietal and other, have been given to the 

 mutations of this species, which barely enters the region covered by 

 this memoir, at its southern border near the Rocky Mountains. The 

 group is viviparous, and the young attain a large size before extrusion. 



Genus Helicodiscus Morse. 



Helicodiscus lineatus Say. 



Helix lineataSw, Journ. Acad. Nat. Sci. Phila., i, p. 18, 1819. — Gould, Inv. 



Mass., p. 179, fig. 103, 1 84 1. — Morse, Am. Nat., i, p. 546, fig. 44, 



1867. 

 Planorbis parallelus Say, Proc. Acad. Nat. Sci. Phila., li, p. 164, 1821. 

 Helicodiscus lineatus yiOKSK, Journ. Portland Soc. Nat. Hist., i, p. 25, figs. 



61, 62, pi. II, fig. 3; pi. VII, fig. 63, 1864. — Binney, Man. Am. Landsh., 



p. 75, figs. 34-37 A, 1885. 



Range. — New Mexico to Manitoba, New England to California. 

 Reported as rare in Manitoba by Hanham. 



Fig. 36. Helicodiscus lineatus, shell and animal (magnified). 



