1198 REPORT OF NATIONAL MUSEUM, 1898. 



We have but few specimens of this species, five only having come 

 under my observation. It is ne?:est the G. tigris Kennicott, but has 

 even fewer scales on the body, presenting the smallest number known 

 in the genus. The labial plates are fewer, and the gastrosteges mate- 

 rially less numerous (28). The partial fusion of the nasal plates is also 

 characteristic of the G. cerastes as of the G. lepidus. 



A small rattlesnake has been long known to the Arizonians as the 

 "sidewinder," from its habit of progressing sidewise instead of in 

 the usual way. It has been ascertained by Dr. J. L. Wortman that the 

 species which possesses this peculiarity is the Grotalus cerastes. Dur- 

 ing an ethnological exploration of the valley of the Salt River, a tribu- 

 tary of the Gila, in Arizona, he frequently observed the snake and its 

 habits. 



In his report on the results of the Death Valley expedition Dr. Mer- 

 riam gives the distribution and habits of this species as follows : 



The horned rattlesuake, or "sidewinder," as it is locally known throughout the 

 region it inhabits, is the characteristic snake of the Lower Sonoran deserts of the 

 Great Basin, from southern California easterly across southern Nevada to Arizona 

 and southwestern Utah. It inhabits the open deserts, while its congener of the 

 same region {C. tigris) lives in the desert ranges. Its local name is derived from its 

 peculiar mode of progression. When disturbed it moves away sideways, keeping 

 its broadside toward the observer instead of proceeding in the usual serpentine 

 manner. Its bite is said to be fatal, which is probably not the case under ordinary 

 circumstances. A large number were secured by the expedition, and many others 

 were killed, but no one was bitten by it. It was found on both sides of Pilot Knob, in 

 the Mohave Desert (April 5 and 6) ; in Pahrump Valley, where four were caught in a 

 space of a mile and a half (April 28 and 29) ; in Vegas Valley (May 1) ; in Vegas Wash 

 (May 3); in Indian Spring Valley (May 29), where one was shot containing a kan- 

 garoo rat (Dijmdomys) and two pocket mice {Pero(inailius); in the Amargosa Desert 

 (May 31), and in Sarcobatus Flat (June 2). It was common in the valley of the 

 Virgin and Lower Muddy (May 6 and 7), and was said to inhabit Pahranagat 

 Valley, though we did not find it there. 



During the latter part of April and the early part of May these rattlesnakes were 

 often found in pairs, and were doubtless mating. At such times they remained out 

 in plain sight over night instead of retreating to holes or shelter under desert brush, 

 and on two occasions they were found by us on cold mornings so early that they 

 were too chilled to move until considerably disturbed. I stepped on one of these by 

 accident as it lay in a compact coil with its head in the center, but it was held so 

 firmly by my weight that it was unable to strike. A moment before, I had killed its 

 mate. I killed three on the mesa east of St. Joe, in the valley of the Muddy, in 

 eastern Nevada, May 7. 



