13. cROTALUS. 583 
light-edged cross-bands narrowing on the sides; two dark spots or 
a V- or heart-shaped black marking on the nape; a dark streak 
behind the eye present or absent ; beneath dirty white spotted with 
brown. : 
In C. palmeri, Garm., which appears to be based on a colour 
variation of this species, the markings are much effaced on the 
body and altogether absent on the head. 
Total length 350 millim.; tail 60. 
Western Texas, New Mexico, Arizona, North Mexico. 
a. 3 (Sc. 23; V. 169; C.31). Milpas, Durango. Hr. A, Forrer [C.]. 
11. Crotalus cerastes. 
Crotalus cerastes, Hallow. Proc. Ac. Philad. 1854, p. 95, and Rep. 
U.S. Surv. R. R. x., Williamson’s Rep. p. 17, pl. iv. fig. 1 (1859) ; 
Kennicott, Rep. U.S, Mex. Bound. Surv. ii. Rept. p. 14, pl. iii. 
(1859) ; Cope, Proc. Ac. Philad. 1859, p. 337 ; Jan, eon Gén. 46, 
pl. iii. fig. 5 (1874); Garm. N. Am. Rept. p. 116 (1883); Cope, 
Proc. U.S. Nat. Mus. xiv. 1892, p. 689; Steyneger, N. Am. Faun. 
no. 7, p. 216 (1893), and Rep. U.S. Nat. Mus. f. 1893, p. 450, 
figs. (1895). 
Caudisona cerastes, Cope, Proc. Ac. Philad. 1866, p. 309, and 1867, 
p. 85. 
——  (AXchmophrys) cerastes, Cowes, Wheeler's Surv. W. 100th 
Mer. v. p. 609 (1875). 
Canthus rostralis rounded. Rostral as broad as deep or a little 
broader than deep, in contact with the nasal, which is single ; snout 
and vertex covered with small scales; supraocular produced into:a 
raised horn-like process; two or three series of scales between the 
eye and the labials; 11 to 13 upper labials. Scales in 21 or 23 
rows, dorsals feebly keeled, each scale along the middle of the back 
with a central tubercular swelling. Ventrals 146; anal entire; 
subcaudals 17. Yellowish above, with a dorsal series of rather 
indistinct brown blotches; a narrow brown streak from the eye to 
the angle of the mouth. 
Total length 250 millim. ; tail 20. . 
Desert regions of Southern California, Nevada, Arizona, and Utah. 
