228 Proceedings of the Biological Society of Washington. 



head, and 60 scales between the interparietal shield and the 

 base of the tail). 



A comparison with specimens of S. microlepidotus from 

 southern and central Mexico shows, moreover, that the Hidalgo 

 specimens, although being closely related to this species, are 

 sufficiently distinct to deserve recognition nomenclatorially, as 

 is also evident from the fact that Boulenger considered the two 

 forms so distinct that he placed them in different sections of 

 the genus. I may add that I fail to realize the distinction in 

 the dorsal lepidosis implied in the description of the two forms 

 by Boulenger, S. ornatus being described as having "dorsal 

 scales forming parallel longitudinal series," while S. microlepi- 

 dotus is said to have them ' ' forming oblique longitudinal series 

 converging toward the median line." As far as I can see, the 

 scutellation is essentially alike and of the latter type. 



Sceloporus disparilis sp. nov. 



Diagnosis. — Lateral scales directed obliquely upwards and backwards, 

 and passing gradually into the dorsals; series of femoral pores widely 

 separated, not meeting on the preanal region; tail cylindrical; head 

 shields smooth ; distance between base of fifth toe and extremity of the 

 fourth slightly exceeding distance between the end of snout and posterior 

 border of ear ; 52-65 scales between the interparietal shield and the base 

 of the tail, 15-17 corresponding to the length of the shielded part of the 

 head. 



Range. — Extreme southern corner of Texas and northeastern Mexico. 



Type. — United States National Mu?!eum, No. 33,041; Lomita Ranch, 

 six miles north of Hidal;:;o, Toxas, June 17, iS'Jl Wm. Lloyd, collector, 

 U. S. Biological Snrvey. 



Description. — Tyi>e: Adnlt male. Head-siiields smooth; two canthal 

 scales between the posterior of which three larger prefrontal shields across 

 the snout; frontal shield divided transversely; posterior frontal broadly 

 in contact with interparietal; interparietal very large, much broader than 

 long and fused with the parietals; five large transverse supraorbitals 

 separated from the frontals and interparietal by a single series of scales 

 and from the superciliaries by a double row of scales; six supralabials 

 separated from the nasals and from the long subocular by a single row of 

 scales, fifth supralabial under the center of the eye ; anterior border of 

 the ear-opening protected by about five small slightly projecting scales ; 

 dorsal scales about the same size as ventrals, rounded behind, distinctly 

 keeled, forming slightly oblique longitudinal series converging towards 

 the median line back of the shoulders ; about 65 scales along the middle 

 line of the back from the shielded part of the head to the base of the 

 tail ; 17 scales in the middle of the back corresponding to the shielded 

 part of the head; lateral scales directed upwards and backwards scarcely 



