Stejneger — A Nexo Lizard from Texas. 19 



prisingly uniform, especially the throe large prcrrontals, the frontals, 

 froMlo-puriotals and interparietals. In one specimen, No. 33,040, the an- 

 terior frontal issemi-dividcd longitudinally, and in a few there is an extra 

 fronlo-parietal due to the division of the fronto-parietal or the separation 

 of the anterior portion of the parietal. The fold across the fore neck is very 

 variable, mostly absent or merely indicated. The variation of propor- 

 tion and size of scales, femoral pores, etc., will be seen from the sub- 

 joined table, but it should be remarked that the great diversity in the 

 scales round the middle of the body is probably due to the difficulty in 

 exactly counting the lateral granules. 



The males have well-developed postanal scutes which are lacking in 

 the females. 



The variation in color is chiefly confined to the degree of distinctness 

 of the dusky markings above. Thus, No. 33,03.3 has several series of 

 blackish dorsal spots edged behind with smaller whitish spots; leg, (in- 

 cluding digits) and tail, are cross-barred with dusky; there is also a 

 well-marked dusky vertical line from eye to edge of lip and a less dis- 

 tinct line between eye and ear. From this specimen there is a complete 

 gradation to the nearly uniform color of the type. There are no indi- 

 cations of longitudinal pale bands on the back, or of any dark band on 

 the sides. 



The females lack the blue, black-edged side patch underneath, and 

 also the horseshoe mark on the fore neck; but there are faint bluish 

 marblings on the throat, and the vertical blackish mark in front of the 

 shoulder is indicated. 



Habitat. — Thus far only found in the Rio Grande Valley from the 

 mouth of Pecos River to Boquillas. This species, therefore, seems re- 

 stricted to the Rio Grande Canon. 



lieinarkx. — This exceedingly distinct species needs no detailed com- 

 parison with other species of this difficult genus. By its continuous line 

 of femoral pores across the preanal region it recalls Scelnporus scalaris, 

 but the latter has large lateral scales and is also otherwise very dif- 

 ferent. The species to which this novelty is most nearly related is prob- 

 Sceloporii.s couchii, in which the femoral pores, however, are restricted to 

 the thighs, but the relationship is not near enough to make any further 

 comparison necessary. 



It will be noted that the type is described as having a distinct cross- 

 fold under the neck, which is the character attributed by Cope to his 

 genus Lymqitychuti, based on a single specimen, from southern Texas. 

 This character is absolutely valueless, as it is absent in most of the 

 specimens, and there is nothing else to separate them from the genus 

 Sceloporux. As a matter of fact Cope's Lysaplychus lateralin is nothing 

 but a specimen of Hceloporus couchii, with the types of which I have 

 carefully compared it. I may here correct a mistake in the original 

 description of the latter (Proc. Phila. Acad., 1858, p. 254), in which the 

 number of femoral pores is given as 25. In none of the type speci- 

 mens (8) is there more than 19 pores on one side. The number varies in 

 the lot between 15-15 and 18-19. 



