82. IPHISA.— 33, TRETIOSCINCUS. 425 
lateral scales large, elongate-cycloid, forming oblique series ; gular 
and ventral scales like the dorsals, forming twenty-seven or twenty- 
eight pairs; three enlarged sternal shields, median triangular; 
twelve scales round the middle of the body. Three large preanals, 
median shortest and elongate-triangular. Limbs with smooth 
shields; hinder side of thighs granulate; upper surface of tibia 
with keeled scales. Male with ten femoral pores on each side. 
Tail long, tapering to a point; covered with hexagonal-lanceolate 
keeled scales forming regular imbricate annuli. Chestnut-brown 
above, with small darker marblings; a more or less distinct light 
lateral line, separating the lighter colour of the dorsal surface from 
the blackish brown of the sides of the head and body; lower sur- 
faces yellowish white. 
millim, millim. 
Total length............ 144 From end of snout to 
Fiead. eax hg ae baie eee 11 OTIC Se. 2 alee vecaiti ee Sas 54 
Width of head .......... 7 Fore limb............ 10 
From end of snout to fore Hind limb .......... 16 
NM essa ew Ges ees 19 Tail (broken) ........ 90 
N. Brazil; Guianas, 
a od. Para (Type.) 
bo. Demerara Falls, 
33. TRETIOSCINCUS. 
Tretioscineus, Cope, Proc. Ac. Philad. 1862, p. 184; Bocourt, Miss. 
Sc, Mex., Rept. p. 452. 
Tongue rather elongate, arrow-headed. Head with large regular 
shields; frontonasal separating the nasals; preefrontals and fronto- 
parietals present ; nostril pierced in the suture of a divided nasal, 
Eyelids developed, lower with a transparent disk. Ear exposed. 
Limbs well developed; inner finger rudimentary, clawless. All the 
svales roundish-hexagonal, imbricate, smooth, or feebly keeled on 
the back, arranged quincuncially. No collar fold. Tail cylindrical. 
Males with femoral pores. 
Colombia; Central America. 
1. Tretioscincus bifasciatus. 
Heteropus bifasciatus, A. Dum. Cat. Méth. Rept. p. 182. 
Tretioscincus castanicterus, Cope, J. ce. 
bifasciatus, Cope, Proc. Ac. Philad, 1864, p. 229; Bocourt, J. ¢. 
p. 453, pl. xxii. F. fig. 4. 
Body moderately elongate. Frontonasal broad; frontal much 
narrower ; parietals broad, short; interparietal subtriangular, as 
long as parietals; a loreal; a row of infraorbitals ; eight upper 
labials ; chin-shields, one anterior and three pairs, all forming a 
suture. Dorsal scales smooth on the nape, becoming gradually more 
and more distinctly keeled towards the tail; sixteen scales round 
