32. II'HISA.— 33. TRKTIOSCINCUS. 425 



lateral scales large, elongate-cycloid, forming oblique series ; gular 

 and ventral scales like the dorsals, forming twenty-seven or tweutj'- 

 eight pairs ; three enlarged sternal shields, median triangular ; 

 twelve scales round the middle of the body. Three large prseanals, 

 median shortest and elongate-triangnhir. 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 anuuli. Chestnut-brown 

 above, with small darker marblings ; a more or less distinct liglit 

 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. 



laillim. millim. 



Total length 144 From end of snout to 



Head 11 vent 54 



Width of head 7 Fore limb 10 



From end of snout to fore Hind limb 16 



limb 19 Tail (broken) 00 



N. Brazil ; Guianas. 



a. J. Para (Type.) 



h. 2 . Demerara Falls. 



33. TRETIOSCINCUS. 



Tretioscincus, Cope, Proc. Ac. P/iilad. 1802, p. 184 ; Bocourt, Miss. 

 Sc. Mex., Rept. p. 452. 



Tongue rather elongate, arrow-headed. Head with large regular 

 shields ; frontonasal separating the nasals ; pra3froutals 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 

 scales roundish-hexagonal, imbricate, smooth, or feebly keeled on 

 the back, arranged quiucuucially. No collar fold. Tail cylindrical. 

 Males with femoral pores. 



Colombia ; Central America. 



1. Tretioscincus bifasciatus. 



Ileteropus bifasciatus, A. Diim. Cat. Meth. Rept. p. 182. 

 Tretiosciucus castanicterus, Cope, I. c. 



bifasciatus, Cope, Proc. Ac. Pliilad. 18G4, p. 220 j Bocourt, I. c. 



p. 453, pi. 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 infraorl)itals ; eight ujjper 

 labials ; chin-sliields, one anterior and three pairs, all forming a 

 suture. Dorsal scales smooth on the na]ie, becoming gradually more 

 and more distinctly keeled towards the tail ; sixteen scales round 



