ZOOLOGY REPTILES. /} 



scales upon the back, very distinctly carinated ; several rows of large scales beneath the infra- 

 labials, the two anterior of the inferior rows much the largest ; collar scaly ; aural apertures 

 strongly denticulated anteriorly ; sides of neck folded ; a fold over the shoulder ; occipital scale 

 large, in contact on each side with the supra-orbital ridge ; scales upon muzzle for the most 

 part narrow ; behind them two transverse rows, the first containing three, the second but two 

 plates; two single plates upon the vertex, the anterior the largest; six narrow pentagonal 

 plates upon each orbit, bordered internally with a row of small scales ; 46 teeth in upper jaw, 

 44 in lower ; color of body yellowish, mixed with brownish and black spots ; extremities 

 yellowish, with dark colored transverse bands ; tail of same color above as body, under surface 

 silvery white, with blackish spots ; eleven femoral pores. 



DIMENSIONS. Length of head, -| inch ; greatest breadth, f inch ; length of head, neck, and 

 body to vent, 1^ inch ; of anterior extremities to extremity of longest toe, f inch ; of posterior 

 to extremity of longest toe, 1 inch; of tail, 4-| inches; total length, 6| inches. 



HABITAT. Southern part of Upper California. 



GENERAL REMARKS. The contrast between the large carinated scales upon the back and the 

 small ones upon the sides, resembling granulations, is striking ; the long and slender tail is 

 also remarkable. In these respects, Uro-saurus is allied to Tachydromus, but the plates upon the 

 head are very different. 



SCELOPORUS, Wiegmann. 1 



SCELOPORUS MAGISTER, Nob. 



SP. CHAR. Larger than any known species of Sceloporus, and remarkable for its large and 

 strongly carinated scales, which are very much denticulated posteriorly ; anterior margin of 

 aural apertures strongly denticulated ; upper part of head, body and extremities, and tail straw 

 color, without spots or blotches ; a black triangular blotch upon each side of the neck, in front 

 of the shoulder, the base below ; two large bluish green blotches upon the abdomen, one on each 

 side and one upon the neck ; the rest of the under surface light straw color ; tail long, very thick 

 at base, tapering near the point ; twelve femoral pores on each side. 



DIMENSIONS. Length of head, neck, and body to vent, 4f inches ; greatest breadth of head, 1^ 

 inch ; length of head, 1 inch ; of tail, 5 inches ; of anterior extremities, 1^ inch ; of anterior 

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

 longest toe, If inch ; total length 9f inches. 



HABITAT. Near Fort Yuma, at junction of Colorado and Gila, also near Tuson, in Sonora, 

 upon a rocky soil. 



GEN. OBS. This species is remarkable for its large size and greatly developed spines. It is a 

 much larger animal than S. spinosus of Wiegmann, and wants the quadruple series of dark 

 colored spots that exist in that animal. The posterior margins of the scales are strongly den 

 ticulated, which is not the case in S. spinosus, one of the characters of which is &quot; squamis pauci- 

 dentatis.&quot; From S. horridus Wieg. it differs in coloration, arrangement of plates upon the head, 

 and in the number of femoral pores, which in the latter are 4-5. 



(1) Tropidolepis, Cuvier. 



