66 Journal of Entomology and Zoology 
Crotalus mitchelli (Cope). 
This specimen was collected by Dr. Hilton and Dr. Munz of Pomona College, at 
Forest Home, San Bernardino Mountains, June 7, 1919. 
Crotalus cerastes (Hallowell). 
One specimen taken at Needles, California, April 1, 1920. These snakes seem to 
be almost entirely restricted to the sandy areas of the desert, rarely wandering from 
them, and then only for a short distance, its mode of locomotion admirably fits it for 
the type of country which it inhabits. The ordinary snake finds difficulty in rapid 
motion over the loose and shifting sand, since part of the tractive power comes from 
a bracing of each loop of the body against that part of the ground which is posterior 
to the loop, and through the movement of the central portion of the body against 
the surface of the ground. It can readily be seen that a shifting and loose surface 
would seriously hinder the progress of the ordinary snake. The ‘“Side-winder,” 
Crotalus cerastes, instead of progressing as do ordinary snakes, longitudinally, pro- 
gresses laterally, leaving separate tracks, each paralleling the other, and angling in the 
direction in which the snake is moving. Each track is approximately the length of the 
snake making it, and is wavy, that is, a series of “S” shaped loops. ‘The tracks 
give no sign of any part of the body moving from one mark to the other, which gives 
the impression that the snake jumps the 3 to 6 inch interval between the tracks. Such is 
not the case, however. When the snake is moving, the body is kept partially looped 
and the advance seems to be through the advancing of the head and tail, while the 
rest of the body is rested on the intervening loop, supporting the rest of the body, 
the weight then seems to be shifted to the head and tail and the rest of the body 
advanced, the whole progression being a series of graceful and continuous movements. 
This seems to be the mode of progression. 
Crotalus atrox (Baird and Girard). 
Taken at Mecca, California, April 4, 1920. Found in the arrow weed where 
it seemed to be fairly common. 
In addition to the above list of specimens from the desert region there remain 
that from the vicinity of Claremont, California, which is as follows: Uta stanshuriana 
hesperis, Richardson; Sceloporus occidentalis bi-seriatus, Hallowell; Phrynosoma 
blainvillii blainvillii, Gray; Gerrhonotus scincicauda webbii, Baird; Anniella pulchra 
pulchra, Gray; Anniella pluchra nigra, Fisher( doubtful location. Specimen not 
labeled. Another from Laguna Beach August 1, 1920); Cnemidophorus tigris stej- 
negeri, Van Denburgh; Plestiodon skiltonianum, Baird and Girard; Lichanura rose- 
ofusca, Cope (two taken from vicinity of Claremont and one from east of Victorville 
by W. M. Pierce) ; Thamnophis ordinoides hamondii, Kennicott; Diadophis amabilis, 
Baird and Girard; Lampropeltis pyromelana multicincta, Yarrow; Lampropeltis 
boylii, Baird and Girard; Rhinocheilus lecontei, Baird and Girard; Hypsiglena 
ochrorhynchus, Cope; Salvadora hexalepis, Cope (taken in Imperial Valley 10 miles 
east of Holtville) ; Coluber constrictor vetustus, Baird and Girard; Coluber flagellum 
frenatus, Stejneger; Coluber lateralis, Hallowell; Pituophis catenifer catenifer, Blain- 
ville; Crotalus oreganus, Holbrook. 
