CROCODILIANS, LIZARDy, AND SNAKES. 299 



UTA Baird and Girard. 



Uta Baird and Gikard, Stansbury's Exped'n, Great Salt Lake, 1852, p. 344. — 



Boui.KxVGEn, Cat. Liz. Brit. Mns., 2d ed., II, 1885, p. 210. 

 Urosaurus Hai.lowei.l, Proc. Acad. Nat. Sci. Pliila., 1854, p. 92. 

 Phymatolepia Dumeril, Arcbiv. d. Museum, VIII, 1856, p. 548. 

 Petrosaunt.s Boulenger, Cat. Liz. Brit. Mus., II, 1885, p. 205. 



A large interparietal, and the plates on rostrum and above orbits 

 large and rather regular. Scales on sides small, granular; those on 

 back imbricated, angular. Digits pectinate below. Femoral pores. 

 Tail long. Ears distinct. A well-marked gular fold of large scales. 

 Sides of neck folded; upper labials square; plane externally, not im- 

 bricate. A long infraorbital; nostrils lateral, subterminal. Tongue 

 scarcely emarginate; lip slightly free with distinct pallets beneath. 

 No palatines. Posterior teeth only tricuspid. 



The i^recediug diagnosis is intended to define a well-marked group of 

 diminutive North American Saurians, which would be taken for Scelo- 

 porus but for their very small dorsal scales and the sharp constriction, 

 or fold, on the lower throat with a band of scales larger than those 

 anterior or posterior to it. The i)lates on the head are nearly as regular 

 as in Sceloporus. It is easily known, by the presence of external ears, 

 from Holbroolia, which has a similar fold on the throat, and which has 

 also the lateral folds of neck and body less distinct, or almost wanting. 



There are three well-marked sections in this group; one with the 

 dorsal scales very small, and only gradually larger than those on the 

 sides, and another with four to six central series of very large cari- 

 nated scales, those on either side abruptly smaller and tuberculate. 

 The tyjDe species, U. stansburiana, belongs to the first; U. ornata to 

 the second division. Dr. Hallowell has proposed a genus Urosaurus 

 for the latter division based on a second sj)ecies, U. graciosus. The 

 gradation from this species, however, to the TJ. stanshuriana through 

 U. schottii and ornata is so very gentle that it is very difficult to draw 

 the line. In all external characters there is little difterence between 

 U. stanshuriana and ornata, except in the character of the dorsal scales, 

 the proportions of tail and body and other features being almost pre- 

 cisely the same. U. ornata and graciosa, on the other hand, agree per- 

 fectly in the character of the dorsal scales, and yet differ widely in 

 proportions and shape of head, body, and tail. 



The species of Uta differ as follows : 



A. Dorsal scales small, smootb, nearly uniform in size. Caudal scales small, smootb, 

 not spinous. Collar not denticulate. Tail depressed; no blue on 

 belly. (Large species.) 

 Median dorsal scales a little larger tban lateral dorsals; body stout, depressed; 



green, witb tliree dorsal black crossbars V. thalassina Cope. 



Similar to U. thalansina, but "witb bind limb much sborter, snout shorter and 

 more truncate, and four black transverse dorsal bars." 



U. rejjcns Van Deiiburgb. 



