394 REPORT OF NATIONAL MUSEUM, 1898. 



SCELOPORUS MICROLEPIDOTUS Wiegmann. 



Sceloporus microlepidotus Wiegmann, Herpet. Mex., 1834, p. 51. 



aS'. grammicus var. a, Wiegmann, Isis, 1828, p. 370. — Fitzinger, Syst. Kept., 1843, 



p. 76.— BocouRT, Miss. Sci. Mex. Kept., 1874, p. 194, pi. xviii bis, fig. 13.— 



Cope, Proc. Anier. Phil. Soc, XXII, 1885, p. 395. — Boulenger, Cat. Liz. 



Brit. Miis., 2d ed., II, 1885, p. 232. 

 Tropidolepis microlepidotus Dumeril and Bibron, Erp. G^n., IV, 1837, p. 307. — 



Gray, Cat. Liz., 1845, p. 76.— Aug. Dumeril, Cat. M^th. ColL Rept., 1851, 



p. 77. 

 Sceloporus dhpar Baird and Girard, Proc. Acad. Nat. Sci. Phila., 1852, p. 127. 



Cephalic plates generally smooth, arrauged very nearly as they are 

 8. variabilis Wiegmann. Prefrontal scales ronnded; two roof-shaped 

 scales on each acanthus rostralis; occipital plate bordered posteriorly 

 by a row of thick scales a little larger than those on the anterior part 

 of the neck; supraoculars arranged in three longitudinal rows, some- 

 times in four or five, making a region of hexagonal scales rather wider 

 than long; anterior border of the auditory meatus having a serrated 

 structure, formed by flat-pointed scutella, slightly larger than those 

 immediately preceding; scales on the back small, rhomboidal and 

 keeled, arranged in from sixty-six to seventy-nine oblique rows extend- 

 ing from the luipe of the neck to a line joining the posterior borders of 

 the thighs; eighteen to twenty-one of the scales equals the length of 

 the upper surface of the head; ventral scales and those of the flanks a 

 trifle smaller; the keels of these latter scales are directed obliquely 

 upward; tail covered with scutella, strongly keeled, as large again as 

 those on the back; fifteen to twenty-two pores under each thigh. 



Upper parts of the body olive green, with a very narrow collar and 

 bands of striped brown, giving a mottled appearance to the flanks. 

 On the lateral part of the belly the males have two longitudinal black 

 bauds, very close together, bordered on the outside with blue. The 

 collar region is sometimes crossed with black; throat a blue gray, 

 thickly dotted with small, black spots. 



Measurements. — Total length, 140 mm.; length of head from the end 

 of muzzle to the posterior border of the occipital plate, 14 mm. ; width 

 of head at the temples, 15 mm.; length of trunk from chin to anus, 61 

 mm.; length of tail, 79 mm.; lenth of tibia, 15 mm. 



Sceloporus microlepidotus, regarded by Wiegmann in Isis as a variety 

 of 8. grammicus, ditters from it only iu having the dorsal scales smaller; 

 but as these are variable in size in both cases, it is very difficult to 

 distinguish always the species. 



The 8. microlepidotus is abundant on the Mexican plateau, ranging 

 north to Guanajuato, where it has been taken by Dr. Dug^s. 



Locality.— ^onth of Chihuahua. Donor, John Potts. 



