May, 1893.] REPTILES OF THE DEATH VALLEY EXPEDITION. 199 



and Utah being - typical of the above name, while those from the great 

 interior valley of California are referable to a subspecies, 0. tigris 

 undulatus. 



Owing to the fact that nearly the entire collection of North Amer- 

 ican Cnemidopkori are inaccessible to me at the present writing, I have 

 been unable to settle the question as to the proper name of the present 

 species to my own satisfaction. It maybe that G. tigris is only a syno- 

 nym pure and simple of G. tesselatus (Say) or they may be trinominally 

 separable. I have therefore retained the name G. tigris, as the speci- 

 mens before me agree perfectly with the type of the latter. 



There is a great deal of individual variation in the amount of black 

 markings and in their intensity, the dorsal pattern being quite distinct 

 in some, while in others it looks as if it had faded out. On the other 

 hand, the black suffusion on throat and breast is equally variable, but 

 neither sex, age, season, nor locality seem to account for the variation, 

 except that it is usually absent in the very youngest. In all the speci- 

 mens the longitudinal striping is very evident, and, in fact, the differ- 

 ence between the general pattern in the only very young- specimen col- 

 lected (No. 18481) and the full-grown ones, apart from individual vari- 

 ation, is but very slight. 



[The whip-tail lizard (Gnemidopfiorus tigris) is nearly as common as the 

 gridiron-tail in much of the area traversed, but is not so strictly confined 

 to the Lower Sonoran Zone, ranging up a short distance into the Upper 

 Sonoran and consequently reaching some valleys in which the former 

 species is absent. In this respect it resembles the leopard lizard 

 (Grota/phytus wislizenii), with which it is usually found. It lives on the 

 open desert and runs with great rapidity when alarmed. 



In California it is abundant in the Mohave Desert, where it ranges 

 westward through Antelope Valley to the Canada de las Uvas (chang- 

 ing to subspecies undulatus), and southward in the wash leading from 

 near Gorman station toward Peru Creek in the Sierra Liebre. In the 

 open canon leading up to Tehachapi Yalley from the Mohave Desert 

 it ranges all the way to the summit of the pass (at Cameron) and prob- 

 ably throughout Tehachapi Valley also, but was not seen there be- 

 cause of a severe cold wind, which lasted all day at the time we passed 

 through. It ranges up from the Mohave Desert over Walker Pass and 

 down on the west slope to the valley of Kern Eiver, where it changes 

 to subspecies undulatus. It is common in Owens Valley, and ranges 

 thence up on the warm, west slope of the Inyo and White Mountains 

 to 2,130 meters (7,000 feet) or higher, opposite Big Pine; and is toler- 

 ably common also in Deep Spring Valley. It is common in Panamint, 

 Death, and Mesquite Valleys, ranging from the latter through Grape- 

 vine Canon to Sarcobatus Flat. In Nevada it is common in the Amar- 

 gosa, Pahrump, and Vegas Valleys, at the Bend of the Colorado, in the 

 valleys of the Virgin and Muddy, and reaches Oasis, Pahranagat, 

 Desert, and Meadow Creek Valleys, and from the latter ranges up 



