4-32 3. IGUANIDJE 



ules between. No series of peripheral spines. Tail proxi- 

 mally broad and fringed with one series of small spines, 

 distally slender, round, without fringe. Scales on front of 

 arm large, pointed, and strongly keeled. Those on chest, 

 abdomen, lower surfaces of thighs and proximal part of tail 

 smooth. Tympanum covered with scales. Femoral pores 

 varying from 1 to 1 5 on each side, usually invading preanal 

 region and there sometimes grouped in more than one series 

 or occasionally meeting the series of opposite side. Males 

 may have enlarged postanal plates. 



The general color above is grayish white, gray, pale yel- 

 lowish gray, or very light buff. There is a large dark brown 

 or black blotch on each side of the neck. There often is a 

 somewhat similar dark blotch in front of the hind leg. This 

 may be yellow, brown or black, and may be continued for- 

 ward along the side of the body to join the nuchal blotch. 

 A smaller dark blotch may be present on the side of the tail 

 behind the thigh. More or less obsolete dark dorsal spots, 

 blotches or undulate cross-bars may be present on the body. 

 The taiL and toes usually show dark cross-bars. The head 

 usually is pale yellowish gray, with a few or many black dots, 

 but maybe entirely black above. The lower surfaces are white, 

 occasionally with orange spots on single scales. 



Length to anus 35 50 53 55 63 65 



Length of tail 14 26 20 23 40 42 



Width of head 12 16 17 17 23 21 



Length of occipital 



spine 1 2*/ 2 2 1 /* 2 l / 2 5 2*/ 2 



Fore limb 17 22 24 25 30 31 



Hind limb 20 30 30 33 40 38 



Base of fifth to end of 



fourth toe 5 8 9 10 11 11 



Distribution. This small species ranges from western 

 Texas and northern Chihuahua west to Sonora (Sierra de la 



