HERPETOLOGY OF ZUNI MOUNTAINS — GEHLBACH 287 



cline may be visualized (fig. 8). This gi-adient of increasing scale 

 size extends into Sonora, Mexico (cf. Oliver, 1943, fig. 1). Two rows 

 of enlarged dorsals on each side of the vertebrals are present in about 

 SO percent of U. ornatus from southern Arizona. In approximately 

 90 percent of those from northern Arizona and Utah, there is a partial 

 or complete third, outer row. 



The rock uta is abundant on mesa edges and cliffs in the Rough- 

 lands and lower Montane Life Belts. Its local distribution is 

 determined apparently by the availabihty of large boulders or by 

 areas of broken, exposed rock; hence, elevational limits are imposed 

 only by the lack of such habitat. Each mesa partially isolated by 

 level grassland is inhabited by a distinctive population marked by 

 close resemblance to local rock color. While these utas usually were 

 observed in a vertical position, they were found rarely in standmg 

 trees and shrubs. Characterization of Urosaurus as a plant-dwelling 

 genus (see Lowe, 1955b) does not hold for U. ornatus in the Zunis. 

 This is well illustrated by its occurrence in montane canyon-head 

 situations and absence from ridgetops. Arboreal vegetation is present 

 in both places, but large rocks or outcrops are not prevalent m the 

 latter. 



Data on reproduction indicates that the oviposition of U. ornatus 

 may coincide with adequate summer moisture conditions. Gravid 

 females with the following snout-vent length, date of coUection 

 (1959), and egg number and size provide circumstantial evidence: 

 54 mm., June 13, 5 avg. 6.7 mm. diameter; 47 mm., July 14, 3 avg. 

 12.8 X 7.0 mm.; 45 mm., July 16, 4 avg. 10.6 x 5.9 mm.; 48 mm., 

 July 16, 2 avg. 12.2 x 6.1 mm. Specunens taken July 23, 1959, had 

 laid their eggs as had Sceloporus graciosus and >S'. undulatus at the same 

 locality. Hatchlings, 25 and 26 mm. snout-vent, were found on 

 August 10; three more, 24, 25, and 27 mm., were collected on August 

 25, the following summer. 



Locality records : 



MCKINLEY CO.: 5.5 mi. SE Thoreau (CU 5625); 6 mi. S. Thoreau (CU 5129; 

 UMMZ 120292) ; 7 mi. S. Thoreau (CU 5610, 5628) ; 8 mi. S. Thoreau (CU 5449) ; 

 5 mi. NE. Thoreau (CU 5686) ; between Thoreau and Continental Divide (UMMZ 

 120310); 4 mi. NNE. Prewitt (CU 5451, 5599; UMMZ 120203); 14 mi. N. Gallup 

 (UCM 6092-93); Valencia cc: 8 mi. SE. Grants (UMMZ 86614); 17 mi. 

 SW. Grants (CU 5127, 5695); 25 mi, S. Grants (MCZ 62308*); 2.5 mi. E. Laguna 

 Pueblo (CU 5678); El Morro Nat. Mon. (CU 5605); 2 mi. W. El Morro Nat. 

 Mon. (CU5445). 



Comparative Material Examined: 



U. 0. linearis. — Arizona: cochise co.: Carr Canyon, Huachuca Mts. (CU 

 3539); 5 mi. SE. Sunnyside (CU 5126); Cave Creek Canyon, Chiricahua Mts. 

 (CU 2469, 5122) , yavapai cc: 1 mi. N. Yarnell (CU 3036, 3513). U. o. schotii.— 

 Arizona: pima co.: Arivaca (CU 1789); 5 mi. NE. Arivaca (CU 2461); santa 



