SCELOPORUS FRONTALIS. 385 



mediano, modico, subheptagonali ; loreo uno. Scutis supralabiaUbus 

 et infralabialibus in unam et dimidiam seriei partem ordinatis. Scutis 

 mentalibus in quinque paria dispositis. Sqnamis postanalibus modicis, 

 rotundis, leviter carinatis. Femorum facie posteriori squamis parvis, 

 acutis, et carinatis, cooperta. Supra cinereo-caerulescente ; abdominis 

 lateribus nigro-caerulescentibus ; regione mediana flavescente vel albes- 

 cente. 



SPEC. CHAR. Vertex plate larger than the anterior parietal ; two 

 pairs of postparietals, smaller than the anterior parietal : foremost 

 pair largest of the two. One pair of latero-occipitals. Middle occi- 

 pital moderate, obtusely heptagonal. One loral plate. One, and a 

 part of another, series of supralabials; one and a half series of infra- 

 labials. Mental shields in five pairs. Postanal scales moderate, 

 rounded, slightly keeled. Posterior aspect of thighs covered with 

 small, acute, and keeled scales. Bluish-grey above ; abdomen 

 bluish-black on the sides, yellowish or whitish upon its middle 

 region. 



STN. Sceloporus frontalis, B. & G. in Proc. Acad. Nat. Sci. Philad. VI, 1852, 175. 



DESCR. The most prominent specific character which distinguishes 

 this species from the preceding ones, consists in the convexity of the 

 frontal region, and, as a consequence, in the bluntness of the snout. 

 The cephalic plates, in their shape and disposition, partake of both 

 S. undulatus and S. occidentalis : the vertex plate resembles that of 

 the former, and the supraoculars those of the latter. Again, the 

 mental shields recall to mind the same parts in S. undulatus. The 

 scales are smaller than in S. occidentalis, and the dorsal ones are not 

 so quadrangular than in either of the species just alluded to, though 

 provided with conspicuous keels. The abdominal scales are slightly 

 notched upon their posterior margin, instead of being tricuspid, as in 

 S. undulatus. The scales under the hind limbs are smooth, as in S. 

 occidentalis: those on the sole of the feet being likewise keeled. 



The color is but imperfectly preserved : the upper regions exhibit 

 a bluish-grey or slate hue ; the sides of the abdomen are bluish-black, 

 whilst its middle region is yellowish or whitish, as well as the inferior 

 surface of the limbs. The throat is bluish-black. 



97 



