no. 2078. REPTILES OF NORTHWESTERN NEVADA— RICHARDSON. 405 



Phrynosoma douglassii hernandesi. 



(Arizona and New Mexico.) 



Total length, average, mal e 

 108.8 mm. 1 

 Size larger. hjM leg, length, average, 

 male 40.6 mm. 



Species showing differences correlated with altitude 



Ph. douglassii hernandesi. 

 (Deeth, Nevada.) 

 Total length, average, female 

 Size smaller^ 



103.4 mm. 

 Hind leg, length, average, 

 female, 37.9 mm. 



PLAIN INHABITING FORM. 



Size larger 



Dorsal sea 



MOUNTAIN INHABITING FORM. 



Sceloporus graciosus. 



(Lake Tahoe, California.) 



,, [Tail length, average, male, 

 Size smaller^ & 



( 63.3 mm. 



Femoral pores less (average 12+). 



Color darker. 



Thamnophis ordinoides elegans. 

 (Lake Tahoe, California.) 



Total length, average, male, 



Size smaller 



409. 8 mm. 

 Tail length, average, male, 

 103.8 mm. 

 Dorsal scale formula smaller (19-21-19-17 



appearing most frequently). 

 Color darker. 



Sceloporus graciosus. 



(Deeth, Nevada.) 



[Tail length, average, male, 

 Size larger^ ^ ° 



° [ 71.9 mm. 



Femoral pores more (average 15+). 



Color lighter. 



Thamnophis ordinoides elegans. 



(Palisade, Nevada.) 



Total length, average, male, 



520 mm. 

 Tail length, average, male, 



132.5 mm. 

 e formula larger (21-19-17 ap- 

 pearing most frequently). 

 Color lighter. 



I have not placed, in this table the form Uta stansburiana hesperis, 

 which differs from U. s. elegans in having small scales and from U. 

 stansburiana in the possession of distinctly keeled scales. It inhabits 

 the upper Sonoran zone of the comparatively cool coastal belt of 

 Southern California, and its range is continuous with that of the more 

 truly lower Sonoran zone form, elegans. It is interesting to note that 

 here, as in the northern species, stansburiana, small dorsals scales 

 are correlated with a cool habitat. 



It is evident from the data here presented that Callisaurus ventralis, 

 Uta stansburiana, Sceloporus magister, and Phrynosoma douglassii 

 hernandesi are smaller in the northern part of their range than in the 

 southern and that reduction in size in the first three species is corre- 

 lated with a reduction in the number of femoral pores. Unfortu- 

 nately, femoral pore counts were not made on the specimens of 

 Phrynosoma from southern localities, but Ruthven (1907) gives 15 to 

 16 as the usual number, about the same as the average for the Deeth 

 specimens. Likewise a comparison of the Sceloporus graciosus from 

 Lake Tahoe, California (altitude 6,225 feet), with those from Deeth, 

 Nevada (altitude 5,342 feet), shows that the former is smaller and pos- 

 sesses a lesser number of femoral pores. Specimens of Thamnophis 

 ordinoides elegans from Lake Tahoe, California, are smaller in size 

 and have a reduced number of dorsal scales, while specimens taken at 



1 Adult males are usually smaller thau adult females. 



