6. CROTAPHYTUS 129 



small plates larger than gulars. Symphyseal plate very- 

 large, with several series of slightly enlarged plates. From 

 one to three transverse gular folds, only the posterior one 

 well-developed. Back and sides covered with small 

 granules, largest centrally, and passing gradually into the 

 larger scales on the belly. Latter imbricate and sometimes 

 keeled. Irregular dermal folds usually present on sides. 

 Tail conical, about twice length of head and body, and 

 covered with whorls of small scales. Femoral pores vary- 

 ing in number from about 15 to 20 in specimens examined. 

 Males with enlarged postanal plates. 



The head is dark brown above, with cream-colored lines 

 and irregular spots and marblings about the snout, occiput, 

 temples and supraocular regions. The back is grayish 

 brown or dark hair brown with white or cream-colored 

 cross-bars, which may either meet or alternate, on the me- 

 dian line, with those of the opposite side. Between each 

 pair of these cross-bars the ground color may be unmarked 

 or may show rounded spots of darker brown. The tail is 

 marked like the back, but less regularly and usually is 

 spotted. The limbs are brown with irregular spots of 

 brown and lines of white or cream. The lower surfaces 

 are yellowish white, marked on the throat with longitudinal 

 lines or spots of gray or pale brown. The whole coloration 

 resembles that of young individuals of C. wislizenii, but 

 usually with less evident brown spotting. 



Length to anus 90 91 92 95 100 105 



Length to tail __.180 177 170 175 178 193 



Snout to orbit... 8 8 8 8 9 9 



Nostril to ear 18 18 19 19 20 20 



Width of head 18 19 19 20 21 21 



Fore limb 36 38 3 8 4-0 39 42 



Hind limb 76 73 75 77 76 79 



Base of fifth to end of 



fourth toe 28 28 27 29 26 30 



