136 3. IGUAN1DM 



individual. Professor Cope later published descriptions of 

 Uma sco^aria, U. inornata and U. rufopunctata. The 

 various characters ascribed to these supposed species have 

 since been found in good series of specimens from single 

 localities, and there can be no doubt that the differences in- 

 dicated by Cope are individual, sexual and age variations in 

 a single species. 



Distribution. This lizard seems to be restricted to sand 

 dunes in the Lower Sonoran Zone. In such situations it has 

 been found in southeastern California, Arizona, northern 

 Lower California, and Sonora. 



In California, it has been collected in San Bernardino 

 (Mohave Desert, Mohave River near Daggett), Riverside 

 (two miles south from Blythe Junction, San Bernardino 

 Mountains east from Coachella), and Imperial (Signal 

 Mountain, New River near Salton Lake, Colorado Desert), 

 counties. 



In Arizona, it has been found on the desert near Yuma, 

 Yuma County, on the Mohave Desert, Mohave County, and 

 near Fort Buchanan, Santa Cruz County. 



In Lower California, it has been secured near Gardner's 

 Laguna, and near Mexicali. 



In Sonora, it has been secured at Tepoca Bay. 



Habits. This curious lizard has been found only on 

 dunes of loose sand. Its habits are similar to those of Calli- 

 saurus to which it is closely related. 



Mr. Heller, as recorded by Meek, states: "This species 

 was taken only in the drifting sand areas of the bed of the 

 Mohave River, where it is a common form. It has the 

 peculiar habit of burying itself in the sand when pursued. 

 The peculiar fringe of scales along the toes evidently serves 

 to give the lizard sufficient speed over the loose sand to 



