6 U. S. p. R. R. EXP. & SURVKYS ROUTE IN CALIFORNIA. 



SCELOPORUS BISEEIATUS, Kub. 



Sp. Chak. — Scales of the back mucb larger than those upon the sides. Five frontal plates in 

 two rows, sometimes a small one intercalated between the two outer of the second row ; the 

 middle of the anterior row largest ; four internasals ; four small plates immediately behind the 

 rostral ; two vertical plates ; one large plate on each side of the occipital, and two in front of 

 them ; posterior border of scales not denticulated. A narrow brownish vitta across the head 

 near the middle of the supraciliary plates ; coloration of head resembling that of S. undulalus ; 

 light ash gray above, with a double row of dark colored spots upon the back, on each side of 

 the dorsal line, extending a short distance upon the tail ; extremities ash colored above, banded 

 witli black ; under surface silvery gray, with two blue blotches, one on each side of the abdomen, 

 and a blue blotch upon the chin ; 20 femoral pores. 



Dimensions. — Length of head, neck, and body to vent, 3 inches ; of tail, i\ inches ; length of 

 anterior extremities, f inch ; of foot anteriorly to extremity of longest toe, -| inch ; of posterior 

 extremity, 1 inch ; of foot, posteriorly, toextremity of longest toe, 1 inch ; total length, *l\ inches. 



Habitat. — Borders of El Paso creek and in Tejon Valley. Constantly climbing up trees, 

 when scared, to a distance of twenty or thirty feet, running along the ground and up the trees 

 very quickly. 



Gen. Obs. — Wants the undulating lines or bars of S. undulatus, these being replaced by the 

 spots above described ; the scales upon the sides are also much smaller than those of S. undulatus. 

 This species resembles very closely S. variabilis of Wiegmann, and is probably the same, not- 

 withstanding certain differences in the description. In the absence of a good drawing, or 

 authenticated specimen, we cannot pronounce, positively, whether they be the same or not, 

 although inclined to the former opinion. Thus the head, according to Wiegmann, is unicolor; 

 and the plates upon the head cannot be said to be ruguloso-carinatis, for they are, for the most 

 part smooth in S. biseriatus. It wants the white lateral line beneath the spots which is observed 

 in S. scalaris Wiegmann. The arrangement of the plates upon the head appears to characterize 

 this species very well, being uniform, with unimportant exceptions, in all the specimens brought 

 by Dr. Heermann. 



Var. a. S. azureus. — Body imiformly blue above, mingled with brown, the blue color predomi- 

 natin"- ; on the sides greenish, with a metallic lustre ; head brownish above ; two large blue 

 blotches upon abdomen, one on each side ; rest of under surface silvery white with bluish tints, 

 especially about the chin ; scales large and strongly carinated, not denticulated posteriorly ; tail 

 stout at the base, much less tapering than in S. biseriatus ; the plates of the head correspond 

 l^recisely with those of the latter animal. 



Dimensions. — Length of licad, neck, and body to vent, 3-^ inches ; of tail, o| inches ; of anterior 

 extremities, 1 inch ; of anterior foot to extremity of longest toe, J inch ; of posterior foot to 

 extremity of longest toe, IJ inch ; total length, 6^ inches. 



Habitat. — Associated with biseriatus. 



Var. B. Vabiegatus. — Body light ash color, with transverse brownish bands and markings 

 coalescing with each other, so as to give the whole a marbled appearance ; head above, ash color 

 mingled with brown ; extremities ash color with transverse bands of brown ; under surface 

 silvery gray without bluish spots or blotches ; 17 femoral pores, remarkably large; tail stout, 

 thick at the base. 



