174 NORTH AMERICAN FAUNA. pSTo.7. 



specimen had evidently been lost by the animal when alive), and yet 

 there is no approach whatever towards the distinctive characters of 

 8. hispid us. 



There is great individual variation in the coloration of this species, 

 especially in the amount of black on the lower parts and in the dark 

 cross bars on the upper surface, and although the latter are particu- 

 larly well developed and denned in the young specimens, several of the 

 older ones are by no means deficient in this respect. It is a curious 

 fact, however, that the distinctness — or even the presence or absence — 

 of these cross bars, especially on the tail, is changeable in the same in- 

 dividual and apparently dependent upon the intensity of the light to 

 which the animal is exposed, an observation which I was able to make 

 on a specimen which was sent to Washington alive. 



I am informed that observations in the field show this species to be 

 a vegetable eater as has already been demonstrated for the 8. Mspidus. 



Beyond rather vague statements as to the general distribution of the 

 present species very little exact information in regard to its range has 

 been published. It is evident that the localities from which the expe- 

 dition brought home its specimens — almost four times as many as in 

 any museum before — form the center of the geographical range of the 

 i chuck- walla.' From here it extends southward along the Colorado 

 Eiver for an unknown distance, ranging westward into the Colorado 

 Desert, and eastward along the Gila into Arizona. Dr. Merriam has 

 now for the first time definitely demonstrated its occurrence in south- 

 ern Nevada and southwestern Utah. 



[The l chuck-walla,' by which name this remarkable lizard is univer- 

 sally known to both Indians and whites (except the Mormons), inhabits 

 many of the Lower Sonoran Desert ranges in the southern part of the 

 Great Basin from the Mohave and Colorado Deserts easterly across 

 southern Nevada to Arizona, and north to the southwestern corner of 

 Utah. It is the largest lizard of the desert region except the Gila 

 monster (Seloderma), which only slightly exceeds it in size. The broad 

 body is black or blackish, and the large blunt tail is usually marbled 

 with white or entirely white. It was generally found on lava or other 

 dark rocks with which its coloration harmonizes. It is a vegetarian, 

 feeding entirely, so far as our observations go, on the buds and flowers 

 of plants, with the addition sometimes of a few leaves. It is much 

 prized by the Panamint Indians as an article of food. A number were 

 eaten by members or onr expedition, and their flesh was reported to be 

 tender and palatable. 



Specimens were secured in the Panamint Eange, the Amargosa Canon, 

 on a lava knoll on the west side of Pahrump Valley, Calif., and in the 

 Lower Santa Clara Yalley in Utah. In the latter locality, they are com- 

 mon both along the canon of the Lower Santa Clara and among the red 

 sandstone cliffs near the village of St. George, and are called ' alligators ' 

 by the Mormons. Dr. Fisher found them in considerable numbers in the 



