82 A MANUAL OF AMERICAN LAND SHELLS. 



for the North American species of this genus, the typical Macrocydis 

 being placed by him in the Relicidie. If he is correct in this latter 

 point, Selenites must be adopted for our American species. 



Macrocydis Vancouv ereiisis, Lea. 



■Shell widely umbilicated, depressed, very slightly convex on the up- 

 FiG. 44. per surface; epidermis light greenish-yellow ; whorls 



5, nearly flat above, protuberant and rounded on 

 the lower surface, lines of growth very minute, with 

 crowded, mi(;roscopic revolving striae, the outer 

 Macrocydis Yancouverensis. ^,^^^j expanding a little towards the aperture; um- 

 bilicus wide and deep; aperture transverse, somewhat rounded, flat- 

 tened above by a depression of the peristome near its junction with the 

 body-whorl, its edge tinged with rufous; peristome thin, acute, slightly 

 reflected at the base of the shell, simple above, the two extremities 

 approaching each other, and connected by a thin callus, which covers 

 the columella. Greater diameter 31, lesser 26'«'^; height, 14'"'^. 



Helix concava, Binney, Bost. Journ. Nat. Hist., iii, 372, pi. xiv (1840), not of Say. 



Helix Vancouvertiisis, Lea, Am. Phil. Traus., vi, 87, pi. xxiii, fig. 72; Obs., ii, 87 

 (1839).— Troschel, ArcL. fur Nat., 1839, ii, 21.— DeKay, N. Y. Moll. ,45 

 (1843).— Pfeiffer, Symbolae, ii, 41; Mon. Hel. Viv., i, 200; in Chemnitz, 

 ed. 2, ii, 146, pi. xciv, figs, 21, 23.— Binney, Terr. Moll., ii, 1G6, pi. xx.— W. 

 G. Binney, Terr. Moll., iv, 19.— Gould, U. S. Expl. Ex., 36, fig. 37 (1852).— 

 Eeeve, Con. Icon., No. 669 (1852). 



Helix vellicafa, Forbes, Proc. Zool. Soc. Lond. Mar. 1850, 75, pi. ix, fig. 1.— Chem- 

 nitz, ed. 2, ii, 454, pi. cliv, figs.. 42, 44.— Reeve, Con. Icon., No. 673 (1852).— 

 Pfeiffer, Mon. Hel. A^iv., iii, 155. 



MacTOcyclis J'^ancoMrerenjis, Tryon, Am. Journ. Conch., ii, 245 (1866). — W. G. Binney, 

 L. & Fr.-W. Sh., i, 54 (1869) : Terr. Moll., V, 90. 



A species of the Pacific Province ranging from lat. 60°, in Alaska, 

 to lat. 37° ; above lat. 49° it passes the Cascade Mountains, and ranges 

 southeasterly into Idaho and Montana.* In these latter localities the 

 species is reduced in size. Throughout the rest of its course it is con- 

 fined to the neighborhood of the coast. It reaches its greatest devel- 

 opment in the region of Astoria. 



Animal short posteriorly, subcylindrical, very light-colored, giving a 

 straw-colored reflection, sides pearly, marked with longitudinal lines 

 of coarse, elongated, squamose granules, about eight or ten on each 

 side. 



The species is very nearly allied to M. concava. The differences ob- 



* A most interesting paper on the distribution of the West Coast species, by Dr. J. 

 G. Cooper, will be found in Vol. IV of Amer. Journ. of Conch. 



