The specimens belong to a compact, rather narrowly umbilicated race 

 of ptycophora, not as large as most Idaho and Washington shells, but notably 

 larger than such Montana specimens as the writer has seen. They are 

 evidently the ones which have already been reported by Whiteaves (1906, 

 p. 119). 



Oreohelix cooperi limitaris (Dawson 1875) 

 Plate I, figures 1-5 



1875. Helix limitaris Dawson, Eep. Geol. Brit. N. Am. Boundary Comm., 



p. 347. 

 1885. P alula strigosa var., immature, Binney, Man. Am. Landsh., p. 261 



(reprints Dawson's description). 

 1895. Palula strigosa var. Taylor, Ottawa Nat., vol. 9, p. 173 



(brief note). 

 1898. Pyramidula solitaria limitaris Pilsbry, Nautilus, vol. 11, p. 140 



(merely catalogued). 

 1905. Pyramidula solitaria var. limitaris Dall,- Land and Freshwater 



Moll. Alaska, p. 49. 

 1916. Oreohelix strigosa limitaris Pilsbry , Proc. Acad. Nat. Sci. Phila., 



1916, p. 353 (merely catalogued). 



1919. Oreohelix cooperi limitaris Berry, Proc. Acad. Nat. Sci. Phila.. 

 1919, pp. 196, 201. 



Material Examined 



Description. The shell is of only moderate size, fairly elevated, with 

 an obtuse apex. The spiral sculpture is obsolete below, and on the upper 

 surface of the whorls is only moderately developed, being much broken 

 and interrupted by the very coarse and irregular lines of growth. The 

 periphery is obtusely angular in front, becoming rounded or but faintly 

 subangular on the forward part of the last whorl. The umbilicus is deep 

 and narrow, contained in the diameter seven to eight times, its circular 

 outline but little interfered with by the slightly reflexed inner lip. 



The colour of the somewhat dehiscent periostracum is a deep rusty 

 brown, irregularly clouded with brownish cream and slaty tones, and with 

 two conspicuous, encircling, seal brown bands, one on the shoulder, the 

 other just below the periphery, with sometimes a lighter and less distinct 

 band interpolated between them, or one or more similar secondary bands on 

 the basal part of the shell, and there is sometimes one just below the suture. 



The embryonic shell seems essentially similar to that of 0. c. apiarium 

 as described (cf. Berry, 1919, p. 200, f. 1), but is smaller, the spiral sculpture 

 is weaker, and the axial riblets stronger and more regular. 



