360 THE CHICAGO ACADEMY OF SCIENCES. 



a trifle inflated, about two-fifths the length of the shell ; peristome thin, 

 sharp, with a slight internal rib, chestnut colored on the edge; inner 

 lip narrow, reflected and appressed to the columellar region leaving a 

 very narrow chink; the parietal callus is thin and narrow; a distinct, 

 sharp but not heavy plait extends across the columella in an upward 

 direction ; the axis is slightly twisted. 



Length. Width. Aperture length. Width. 



21.00 8.50 8.50 4.00 mill. Type, proxima. 



24.00 10.00 11.00 5.50 " San Francisco, Cal. 



27.50 11.50 12.00 6.50 " San Mateo, Cal. 



28.00 12.00 13.00 7.00 " 



18.00 8.00 7.50 4.00 " Wyoming. 



TYPES: Proxima, Lea, two specimens, Smithsonian Institution, 

 No. 29082; cotypes, Philadelphia Academy of Sciences, No. 58503; 

 calif 'arnica, Sowerby and interstriata, Sowb., British Museum of Natu- 

 ral History, London, England. 



TYPE LOCALITY : Proxima, Arroya, San Antonio, Cal. ; calif ornica, 

 California ; interstriata, California. 



ANIMAL, JAW, RADULA and GENITALIA : Not examined. 



RANGE: (Figure 42) California to Wyoming; Washington south 

 to Southern California. The regional map shows that proxima is 

 common to the Columbian, Coloradoan, Great Basin and Californian 

 regions. It is also characteristic of two great river systems, the Co- 

 lumbia and the Colorado. The records show that proxima has a wide 

 range in Western America from the 35th to the 48th degree of North 

 latitude. It seems to thrive from near the sea level to a height of over 

 7,000 feet. 



RECORDS. 



CALIFORNIA : Mountain stream near San Francisco, San Francisco Co. 

 (Button; Cooper; Nason; Rowell; Stearns; Walker); San Mateo Co. (Hemp- 

 hill) ; South Fork Pitt River, Modoc Co. (McGregor) ; Arroya, San Antonio, 

 San Bernardino Co. (Lea; Trask). 



OREGON: Dallas, Polk Co. (Dall; Stearns); southeast Oregon (Gabb) ; 

 Steins Valley, Harney Co. (Tryon). 



UTAH : Near Salt Lake City, Salt Lake Co. (Hemphill) ; near Logan, 

 Cache Co. (Hemphill; Keep; Walker); Beaver City, Beaver Co., high up in 

 Wasatch Mountains (Palmer); Bear Lake, Rich Co. (Walker). 



WASHINGTON: Spokane, Spokane Co. (Smith. Inst) ; Columbia River 

 (T. B. Wilson). 



WYOMING: Alkali Springs, forty miles north of Almond, Sweetwater Co. 

 (W. C. Knight). 



GEOLOGICAL DISTRIBUTION: Unknown. 



ECOLOGY: In mountain streams or small lakes, generally at high 

 altitudes. 



