CROCODILIANS, LIZARDS, AND SNAKES. 229 



(1) Upper labials rectangular, not imbricated nor obli(|ue; outer face 

 plane, and vertical, nearly round, or compressed, never much depressed ; 

 tail generally much longer than the head and body, except in ISauro- 

 nialns; no black spots on sides, except in Uta; nostrils mostly lateral 

 or superolateral. 



a. With palatine teeth. 



Sauromalus. — Tail shorter than the body, conical. Scales small but 

 imbricated and angular throughout. Infraorbitals in a series of small, 

 nearly equal plates. Plates above head numerous, all small; smaller 

 in the outer part of supraorbital region. Posterior cheek teeth with 

 five cusps. Claws very thick and strong, anterior larger. 



GrotaphyUis. — Tail much longer, slender, and rounded. Scales above, 

 all about equal, small, rounded, not imbricated, and with much smaller 

 ones between them. Supraorbital spaces with plates abruptly much 

 smaller than the intermediate plates. Infraorbital plates small, nearly 

 equal. Pallet beneath the tip of tongue large, ovate, very thin, sessile. 



/3. Without palatine teeth. A very long infraorbital. 



DipsosauTus. — Plates on head all very numerous, small, angular, 

 nearly equal, and in indefinite number. Tail long and compressed. 

 Body compressed. Scales on body rhomboidal. Body and tail with a 

 single median dorsal series of much larger cariuated, but not crested 

 nor spinous, scales; the others on back and sides equal and smaller 

 than the ventral. 



Uta. — Plates on the head, including occipital and supraorbitals, 

 rather large, angular, and in rather regular series of definite number. 

 Dorsal scales carinated, imbricated, larger than the lateral, which are 

 tessellated, but nearly eipial to the ventral and, like them, lozenge- 

 shaped or hexagonal. Tail rounded, longer than head a. id body. Sides 

 of belly, blue. 



(2) Upper labials lozenge-shaped, mm;h imbricated and oblique; outer 

 face with an oblique angular carina or else plane and vertical. Body 

 depressed. Tail depressed, shorter than head and body. Nostrils 

 superior. Sides of body or of belly, and generally the under surface of 

 tail, with black patches. Ears distinct, except in Holbroolda. Lowest 

 infraorbital much longest. No palatine teeth. Scales above nearly 

 equal, much smaller than ventral. Claws long, nearly straight. 



{a) Ears distinctly visible. 



TJma. — Upper labials oblique, overlapping forward. Claws exca- 

 vated on one side, turned forward, long, slender, and straight. Sides 

 with a round black spot. A series of long scales movably articulated 

 at the base to the external side of the hind foot. 



Calllmurus. — Outer face of upper labials with a long, oblique, angular 

 carina. Sides with black crescents; tail blotched beneath with black. 

 Feet simple. 



{!)) Ears concealed. 



Holbrookia. — Outer face of upper labials angular, as in the last. 

 Interorbital space with a large central and a smaller irregular lateral 

 scale on each side. 



