Siuromsilus and Crotapbytus 



in colour, being dull brown, olive or black above; abdomen 

 rusty red, dotted with black. 



The young are usually olive, marbled or spotted with black 

 on the back; some are banded with reddish, this intermixed 

 with yellow dots. The pattern is more pronounced on the tail. 



Dimensions. — The measurements given are from a specimen 

 taken a few miles south of Phoeni.x, Arizona: 



Total Length 12 inches. 



Length of Fail 5 



Width of Body 3 



Width of Tail, at base ij 



Width of Head if " 



Distribution. — Desert regions of the southwestern United 

 States — southern Nevada and Utah, .\rizona, eastern California, 

 Lower California, and northern Sonora, Mexico. 



Habits. — Little is known about the habits of the Chuck- 

 awalla or "Chuck-walla." It inhabits rocky places in the deserts. 



The single living specimen in the writer's collection lived 

 but a few months. When sleeping it was dark brown, but as 

 the sun shone upon the sand of its cage and it became more 

 active the body hue grew much lighter — almost yellow. This 

 lizard had a very poor appetite. It occasionally nibbled at 

 tender leaves of lettuce and celery. Dissection of the stomachs 

 of preserved specimens shows the Chuckawalla to be quite her- 

 bivorous. 



The Genus Crotaphytus: The three species are confined 

 to the southern United States and northern Mexico; they are 

 of moderate size. 



Body stout, head large; tail very long, cylindrical and slen- 

 der. Above and beneath, the scales are fine and granular. Top 

 of the head covered with small, granular scales — larger than 

 those of the body; scalation of the tail in narrow rings. Ear 

 drum large; a fold of skin on the throat. 



Key to the Species 



I. Head very large; body short and stout. 



Pale, with numerous white or yellow dots; a double 

 black collar on neck. 



COLLARED LIZARD, Crotaphytus collaris. 

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