504 Mlt. G. A. BOTJLENGER ON THE [May 18, 



Scelo2)orus occidentalis, Baird & Gir. 1. c. p. 175; Grirard, I.e. 

 p. 383, pi. xix, figs. 8-14 ; Stejneger, N. Am. Faun. no. 7, 1893, 

 p. 186. 



Sceloporrxs frontalis, Baird & Grir. 1. c. ; Gir. 1. c. p. 384, pi. xix, 

 figs. 8-14. 



Sceloporus loncjipes, Baird, Proc. Ac. Philad. 1858, p. 254. 



Scelojporus hiseriatus, Hallow. Eep. U.S. Explor. Surv. E. E. x. 

 pt. iv. p. 6, pi. vi. fig. 2 & pi. viii. (1859) ; Bocourt, 1. c. p. 197, 

 pi. xviii. bis, fig. 10 ; Cope, Proc. Amer. Philos. Soc. xxii. 1885, 

 p. 395 ; Stejueger, 1. c. p. 184. 



Scelo2)orus smaragdinus (non Bocourt), Cope, in Wheeler's Eep. 

 Explor. W. 100th Mer. v. p. 572, pi. xxiv. fig. 2 (1875). 



Sceloporus undidatus, var. hocourtii, Bouleng. 1. c. p. 229. 



Some or all of the head-shields more or less rugose, rarely- 

 smooth, the scales between the enlarged supraoculars and the 

 supraciliaries nearly constantly keeled or tuberculate ; frontal 

 transversely divided, usually in contact with the interparietal; 

 latter as long as broad, a little longer than broad, or a little 

 broader than long, much larger than the parietals, which may be 

 divided ; a series of four or five more or less enlarged, transverse 

 supraoculars, bordered inwards by a complete (rarely incomplete) 

 series of scales and separated from the supraciHaries by one or 

 two series ; two canthal scales (rarely one) ; four or five pointed 

 scales, as large as or larger than those before them, form a denticu- 

 lation on the anterior border of the ear. 



Dorsal scales much larger than ventrals, as long as broad or 

 a little broader than long, strongly keeled, rather strongly mucro- 

 nate, entire or feebly denticulate, the keels forming parallel lines 

 or obliquely convei-ging towards the middle line on the posterior 

 part of the back ; 32-43 scales between the interparietal shield 

 and the base of the tail ; 7-9 (exceptionally 10) scales, taken in 

 the middle of the back, correspond to the length of the shielded 

 part of the head. Lateral scales graduating into dorsals and 

 ventrals, keeled, pointing upwards and backwards. Ventral scales 

 small, smooth, bicuspid. 36-48 scales round the middle of the 



body. 



The adpressed hind limb reaches the shoulder, the collar-fold, or 

 the ear ; tibia as long as or a little longer than the shielded part of 

 the head ; the distance between the base of the fifth toe and the 

 extremity of the fourth equals or slightly exceeds the distance 

 between the end of the snout and the collar-fold. 13-19 femoral 

 pores on each side. 



Caudal scales as large as or a httle larger than dorsals, strongly 

 keeled and mucronate. Males with enlarged postanal scales. 



The typical form, inhabiting the Eastern and Central United 

 States and the border of the Gulf of ]Mexico, is grey, brmyn, 

 or copper-colour above, with a dorso-lateral series of whitish 

 or bluish spots or lateral bands crossed by transverse dark brown 

 or black angular spots, or undulous or zigzag cross-bars, which 

 may extend across the back. In males, the sides of the belly are 

 blue or blue-green, edged with black along a whitish stripe which 



