48. CROTALUS O55 
or vinaceous tinge, with a series of rather small and indefinite 
blotches of grayish or yellowish brown. There usually are 
from 31 to 33 of these blotches between the head and anus, 
and from three to nine on the tail. Smaller blotches or 
spots usually are present on the sides and on the tips of the 
gastrosteges. The supraocular shows an indistinct trans- 
verse streak. A brown streak runs from the eye to the cor- 
ner of the mouth. The tail is ash-color with half rings of 
brown, which are much darker near its tip than anteriorly. 
The lower surfaces are yellowish white, sometimes faintly 
clouded with brown or gray. 
Length to anus_..__.._- 404 415 428 440 450 592 
Length of tail to rattle... 30 38 42 42 31 38 
Distribution —The Sidewinder occupies the lower levels 
of the Colorado and Mohave Deserts in California, where 
the Tiger Rattler occurs in the mountainous districts, and 
ranges thence across Arizona and southern Nevada to “south- 
western Utah.” 
It is known to occur in southern Nevada in Pahrump, 
Vegas and Indian Spring Valleys, at Sarcobatus Flat, in the 
Amargosa Desert, and in the valleys of the Virgin and 
Lower Muddy, and in Cottonwood Canyon. 
In Arizona, it has been found at Yuma and Chrystoval, 
Yuma County; Salado Valley near Tempe, Maricopa Coun- 
ty; Fort Buchanan, Santa Cruz County; and at Vulture. 
It is said to be common in northeastern Lower California, 
where it is confined to the lower gulf strip, and has been 
secured at San Felipe. 
In California, it has been taken at Chalput, Mono Coun- 
ty; Keeler and Lone Pine in Owen’s Valley, Borax Flat, 
Panamint Valley, Mesquite Valley, Ballarat, Echo Canyon 
in the Funeral Mountains, Furnace Creek Ranch and Ben- 
nett Wells in Death Valley, Inyo County; Barstow, Daggett, 
