334 3. IGUAN1DJE 



Length to anus 50 68 88 106 109 120 



Length of tail 67 99 112 149 158 



Snout to ear 12 16 20 24 25 26 



Width of head 10 14 16 24 25 27 



Snout to back of 



interparietal 11 15 17 20 20 23 



Fore limb 28 31 42 45 53 52 



Hind limb 35 49 58 68 72 78 



Base of fifth to end of 



fourth toe 14 19 23 25 28 28 



Remarks. S. magister occurs in parts of Arizona with 

 S. clarkii. These two species were long confused, but may 

 usually be distinguished readily by the shape of the scales 

 of the ear-denticulation and by the coloration. 



S. magister is very closely related to both S. zoj- 

 teromus and S. rufidorsum, of Lower California, from 

 which it seems to differ in little but coloration and the num- 

 ber of femoral pores. S. magister lacks the parallel, dark 

 lines seen on the sides of S. zosteromus, and the mid-dorsal 

 light stripe of S. rufidorsum. It often has a dark brown 

 dorsal band not developed in those species, and seems in 

 general to be less brilliantly colored. These remarks apply 

 to adult males, the females and young being perhaps indis- 

 tinguishable. 



S. magister sometimes attains great size. Ruthven men- 

 tions one with a total length of 285 mm., 140 mm. to vent, 

 with girth 125 mm. 



Distribution. The Desert Scaly Lizard is nearly con- 

 fined to the desert regions of Arizona, western New Mexico, 

 southwestern Utah, southern and western Nevada, southern 

 California, Sonora, and northwestern Lower California. 



In Arizona, it has been secured in Pima (Tucson, Fort 

 Lowell, Santa Cruz River, Catalina Mountains, Roeble's 

 Ranch near Coyote Springs), Maricopa (Tempe, Phoenix, 



