682 THE MONTHLY BULLETIN. 



ashy, head less richly coppery, and under surface of body and upper surfaces of feet 

 whiter ; under surface of tail medially ochraceous-tawny. Because the lighter colors 

 are paler in tone, the jet black side-stripes stand out with greater sharpness than in 

 the Sierran race. 



Color variations. — As in the Sierra Golden-mantled Ground Squirrel. In some 

 specimens in fresh pelage the throat is pure white without a tinge of buff. Half- 

 grown young just out of their nest-burrows show the characteristic paleness of their 

 subspecies to as great a degree as adults in new coat. The pallidness of the adults 

 in old worn breeding dress is greater in degree than in the Sierran race, evidently 

 due to the greater bleaching effects of the more intense sunlight and dryness to which 

 the Inyo animals are exposed. The innate paleness of the Inyo race is thus accentu- 

 ated by external factors. 



Measurements. — Average and extreme measurements, in millimeters, of twenty full- 

 grown specimens from the White Mountains, Mono and Inyo counties, are as follows : 

 Ten males: total length, 26S (260-279) ; tail vertebrse, 92 (8(K105) ; hind foot, 40 

 (38-43) ; ear from crown, 13.4 (11.0-15.0) ; greatest length of skull, 42.9 (42.0- 

 44.0) ; zygomatic breadth, 26.2 (25.0^26.9) ; interorbital width, 10.0 (9.0-11.3). Ten 

 females: total length, 264 (254-286); tail vertebrae, 85 (78-89); bind foot, 38 

 (36-42) ; ear from crown, 13.3 (10.0^-16.0) ; greatest length of skull, 41.4 (39.6- 

 42.3) ; zygomatic breadth, 25.9 (25.0-26.6) ; interorbital width, 9.8 (9.3-10.2). 



As will be seen from the above measurements in comparison with those given for 

 the Sierran race, there are no important size differences between perpallidus and 

 chrysodeirus; indeed it seems likely that, with large enough series, such discrepancies 

 as are here in evidence would disappear altogether. The same variations due to age 

 and sex seem to be present. 



Weights. — Average and extreme weights, in grams, of twenty full-grown specimens 

 from the White Mountains, Mono and Inyo counties, are as follows : Ten males, 182 

 (166.5-199.5) ; ten females, 160 (141.0-200.1). Averages, in ounces: males, about 

 6i ; females, about 53. 



There were no gravid females in this lot. All were taken before August 10 and 

 so none had become very fat. These facts may account for the lesser weights than 

 shown for the Sierran race. 



Type locality. — White Mountains at 10,300 feet altitude, near Big Prospector 

 Meadow, Mono County, California (Grinnell, 1918, p. 429). 



Distribution area. — The upper portions of the arid mountain ranges of extreme 

 eastern California lying east and north of Owens Valley, namely the Inyo and White 

 Mountains, and the mountain mass lying southeast of Mono Lake. Northernmost 

 station. Mono Craters, Mono County (Mus. Vert. Zool.) ; southernmost, summit of 

 Inyo Mountains east of Lone Pine (Elliot, 1904, p. 288). Along this extent of 

 territory the distribution of the animal is^ not continuous but is interrupted at the 

 lowermost gaps between the Inyo and White Mountains and at the extreme head of 

 Owens Valley. Zonally, this race belongs to Boreal, but it extends down locally as 

 low even as Upper Sonoran (see fig. 23). In other words, it extends from above tim- 

 berline down to as low as 7,000 feet altitude (lower edge of pirions), the latter level 

 for it being recorded from the bottom of Silver Canyon east of Laws. The highest 

 observed station of occurrence is McAfee Meadow, 11,600 feet, near White Mountain 

 Peak (Mus. Vert. Zool.). 



Specimens examined. — A total of 50, from the following localities in California: 

 Mono County : Mono Mills, 4 ; Mono Craters, 1 ; McAfee Meadow, White Mts., 7 ; Big 

 Prospector Meadow, White Mts., 22; Cottonwood '^reek. White Mts., 1, Inyo 

 County : Roberts Ranch, Wyman Creek, White Mts., 2 ; Silver Canyon, White Mts., 4 ; 

 Black Canyon, White Mts., 5 ; Mazourka Canyon, Inyo Mts., 4. 



This is simply a pale desert-range race of Golden-mantled Ground 

 Squirrel, probably cut off but incompletely from its near relative, 

 chrysodeirus, of the Sierra Nevada. There can hardly be expected to 

 be any decided differences in habits between the two; yet the different 

 "setting" of perpallidus — exceedingly dry, rocky slopes, with only 

 sparse timber at best — has left in our minds an impression of distinct- 

 ness. This only goes to show that we cannot conveniently, nor should 



90 



