322 REPORT OP NATIONAL MUSEUM, 1898. 



body, wborled irregularly above and regularly below, presenting every-' 

 where the large scales imbricated and keeled. Limbs short, the length 

 of the tibia scarcely equaling the space comprised between the end of the 

 muzzle and the exterior border of the occipital plate; the front of the 

 arms and thighs and the external part of tlie legs furnished with keeled 

 and imbricated scales, nearly as large as those of the tail; the granu- 

 lations resemble those of the flanks protecting the back of the thighs. 

 The feet are covered above and below with small keeled scales. Eleven 

 or twelve pores on each thigh. Male with two large glossy scales 

 behind the arms. 



Measurements. — Total length of male, 140 mm. ; length of head above, 

 125 mm.; length of head below, taken from chin to pectoral fold, 17 

 mm.; length of head at the level of the temples, 11 mm.; length from 

 pectoral fold to arms, 38 mm.; length of tail, 83 mm.; length of tibia, 

 115 mm. 



General color, a greenish gray, with limbs and tail shaded with red- 

 dish brown; a black stripe forming a collar passes across the neck; 

 traces of the same color cross the head, back, and flanks; the limbs, 

 toes, and tail equally crossed by small brown bands. Inferior regions 

 tinted yellow lightly stippled with brown ; males have the entire abdom- 

 inal region a bluislj gray, a mode of coloration approaching that seen 

 in animals of the same sex belonging to the genus Scelojwrus. 



This species occurs throughout Mexico, as far north as the city of 

 Chihuahua, where it was obtained by Mr. Edward Wilkinson. 



UTA NIGRICAUDA Cope. 



Ufa nifjricauda Cope, Proc. Acad. Nat. Sci. Phila., 1864, p. 176; 1866, p. 312.— 

 Garman, Bull. Essex Inst., XVI, 1884, p. 16.— Boulkngeu, Cat. Liz. Brit. 

 Mus., 2 ed., II, 1885, p. 212.— Belding, W. Amer. Scientist, III, 1887, 

 No. 24, p. 98.— Van Denburgh, Proc. Cal. Acad. Sci., 1895, p. 106. 



Series of large dorsal scales narrow, embracing sev^en rows of uni- 

 form size; the scales smaller than the smooth abdominals, keeled, those 

 posterior larger than those in the anterior part of each row. Laterals 

 minute, flat; caudals largest of all, very strongly keeled; antebrachials 

 and prefemorals larger than dorsals, keeled. Two dermal folds on each 

 side, and a strong one in front of gular fold, besides a few cross folds 

 in front of shoulder. Ear large, with three small fringe scales. Lateral 

 occipitals small; frontal long, undivided, preceded by five large scales, 

 of which the posterior pair is in contact on the median line. Five 

 rather broad supraorbitals, separated from marginal row by minute 

 scales. Infralabials, five on each side, large, separated by one row of 

 smaller scales from labials; the anterior pair in contact. Eleven and 

 twelve femoral pores. End of muzzle to ear, 10.4 ram. ; from ear to vent, 

 3(5 mm.; vent to end of tail, 79 mm.; anterior limb, 19 mm.; posterior, 

 29 mm.; hind foot, 14 mm. 



Brown above, sometimes very dark, with seven short, lateral, black 



