CROCODILIANS, LIZARDS, AND SNAKES. 



385 



SCELOPORUS THAYERII Baird and Girard. 



SceloporuH thayerli Baird and Girard, Proc. Acad. Nafc. Sci. Phila., VI, 1852, p. 



127.— Bairo, U. S. ami Mexican Boimd. Surv., II, 1850, Kcptilia, p. 6.— Bo- 



couuT, JNIiss. Sci. Mex., 1874, p. 176, pi. xviii, ii<f. 5. 

 Scelo2)orits coiisobrinns Baikd and diHAUO, Marcy's Kept. Nat. Hist. Red River, 



1853, p. 237. 



Cephalic plates much as in S. undulatm. Frontal undivided. Free 

 portion of long hind toe reaciiing from mouth to middle of occipital 

 plate. Dorsal, rump, and caudal scales about eipuil, tlic front rather 

 hirger than the lateral scales. Scales above angular pointed, with 

 conspicuous keel and spine, with decided lateral denticulations. Belly 

 scales are quite decidedly carinated, those ou inside of the tibia and 

 behind anus still more so. There are about forty-two oblicpio series of 

 scales on each side the back, about twenty-eight or thirty from tho cer- 



Fig. 62. 



SCELOPORUS THAYERII BAIED AND GlKARD. 



< 2. 5. 

 Texas. 



Cat. No. 5887, U S.N.M. 



vical folds. Femoral pores about twelve or lifteen. Light lines on each 

 side of the back, separated by six or .seven scales only; between these 

 two series of dark blotches. I\lale with a continuous, well-marked black 

 stripe on the sides, from above the arm, and a blue patch on each s^ide 

 the belly; black internally and behind; a black patch cm each side the 

 posterior half of chin, sometimes (not always) confluent internally, each 

 one with another always distinct one of blue. 



Tiiis species has a close resembhviice to S. undKlatus, and sometimes 

 is distinguished with great diiliculty. The interparietal is larger, the 

 parietals smaller, and two on each side instead of one. The scales are 

 more strongly cariimted. The light stripes on each side the back are 

 near together, being separated by an interval of only six or eight scales 

 instead of ten. The black lateral stripe is much more distinct. There 

 is a greatei- interval between the blue patches on the belly. The blue 

 NAT MUS 98 25 



