688 THE MONTHLY BULLETIN. 



Males seem to be a little larger than females, on an average, with proportionally 

 longer tails. We are unable to find anything in our material to indicate variation 

 in measurements with either altitude or latitude within the state of California. 



Weights. — Average and extreme weights, in grams, of twenty adult specimens 

 from Inyo County are as follows: Ten males, 104.4 (94.5-120.7) ; ten females, 104 

 (83.6-115.0). Average in ounces, for both males and females, about 3f. 



Type locality. — San Gorgonio Pass, below [east of] Banning, Riverside County, 

 California (Merriam, 1889, p. 20; Stephens, 1906, p. 75). 



Distribution area. — In general, the southeastern desert region (see fig. 24). Life- 

 zone chiefly Lower Sonoran, but extends locally up through Upper Sonoran and even 

 into Transition (see fig. 2S). More specifically, the Colorado and Mohave Deserts 

 (not, however, in some of the sandier or low-lying parts) from the Mexican line 

 on the western rim of the Imperial Valley and the vicinity of Picacho on the 

 lower Colorado River, north to the extreme head of Owens Valley in the vicinity 

 of Benton, Mono County (Mus. Vert. ZooL). 



Along the western edge of the area inhabited by this squirrel, it extends well up 

 onto the sides of the confining mountains and often far through the passes, as far as 

 arid conditions prevail ; for example, in San Gorgonio Pass, Riverside County, above 

 Cabezon, and over Walker and Kelso passes, in Kern County, down the valley of 

 the South Fork of the Kern River to as far at least as Weldon (Mus. Vert. ZooL), 

 thus well over the rim of the San Joaquin basin. There are in southern California 

 at least two outlying colonies on the Pacific side of the desert divides ; namely, in 

 San Jacinto Valley, Riverside County (Grinnell and Swarth, 1913, p. 326), and in 

 Lytle Creek wash within six miles northwest of San Bernardino, in San Bernardino 

 County (Mus. Vert. ZooL). 



Altitudinally, the species ranges from below sea-level, as at Furnace Creek Ranch, 

 — 178 feet, in Death Valley, up regularljr to 6,000 feet on most of the desert moun- 

 tains which reach that height, and in some instances to 7,500i feet, as at the north 

 base of Sugarloaf in the San Bernardino Mountains (Grinnell, 1908, p. 141), and 

 even to 8,500 feet, as near the head of Mazourka Canyon, in the Inyo Mountains 

 (Swarth, MS). 



Specimens examined. — A total of 271, from the following localities in California. 

 Mono County : Benton, and two miles south of Benton Station, 11. Inyo County : 

 Laws, 6; Silver Canyon, White Mts., 9; Mazourka Canyon, Inyo Mts., 5; Independ- 

 ence, and two miles north of Independence, 19 ; west base Kearsarge Pass, Sierra 

 Nevada, 4; Lone Pine Creek, 4,500 ft., 10; Carroll Creek, 5,500 ft., and Hockett 

 Trail, 6,500 ft, near Carroll Creek, 4 ; Keeler, 31 ; Olancha, 2; Darwin (fifteen miles, 

 and two miles, north of), 7; Panamint Mts. (Emigrant, Wild Rose, Ilanaupah, and 

 Johnson canyons), 17; Furnace Creek Ranch, and Triangle Spring, in Death 

 Valley, 13 ; Shoshone, 2 ; Little Lake, 2. Kern County : Weldon, Onyx, and west 

 slope Walker Pass, 16 ; one mile east of Warren Station, 1 ; Mohave, 12. Los Angeled 

 County : Fairmont, 8. San Bernardino County : one mile northeast of Barstow, 1 ; 

 Oro Grande, 2 ; mountains on west side of Colorado River, lat. 35°, 1 ; Blythe Junc- 

 tion, 1 ; five miles below Needles, 1 ; opposite The Needles, 5 ; Chemehuevis Valley, 

 2; Victorville, 14; San Bernardino Mts. (Cushenbury Springs, Cactus Flat, Doble, 

 north base of Sugarloaf), 17; Cajon (Lytle Creek) Wash near San Bernardino, 1. 

 Riverside County: base of San Jacinto Mts., near Cabezon, 7; Snow Creek, near 

 Whitewater, 5 ; Vallevista, San Jacinto Valley, 4 ; Palm Springs, 7 ; Carrizo Creek 

 and Dos Palmos Springs, Santa Rosa Mts., 5; Palm Canyon, San Jacinto Mts., 1; 

 Riverside Mt., near Colorado River, 1. San Diego County : San Felipe Valley, 2 ; 

 Grapevine Spring, 1; La Puerta, 2; Vallecito, 2; Jacumba, 1; Mountain Spring, 1. 

 Imperial County : Colorado River, opposite Cibola, 2 ; twenty miles north of Picacho, 

 4 ; eight miles east of Picacho, 2. 



The Antelope Ground Squirrels constitute a group distinct in many 

 ways from all our other species. They are hardly less inhabitants of 

 the ground, as compared with the tree squirrels and true chipmunks, 

 but in manner they are more vivacious than any of the other ground 

 squirrels ; they run at a much faster clip and hence can forage at greater 

 distances from safety refuges. Their coloration is distinctive, too, 

 gray, with one white stripe along each side of the back, and with the 



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