196 



MEMOIRS OF THE CARNEGIE MUSEUM 



internasals (in one case slightly more); rostral a little broader than deep, visible 

 from above ; internasals broader than long, or as long as broad, much shorter than 

 the prefrontals; frontal once and two-thirds to twice as long as wide, longer than 

 its distance from the end of the snout, shorter than the parietals; loreal once and a 

 half to twice as deep as long; one preocular and two postoculars; temporals 1, 2; 

 eight upper labials, the fourth and fifth bordering the orbit; five lower labials in 

 contact with the anterior chin-shields, which are as long as, or (usually) consider- 

 ably longer than, the posterior. 



Scales in seventeen rows; anal divided; gastrosteges 156 to 161; urosteges in 

 52-60 pairs. Length of tail five and one-third to six times in the total length. 



Olive above, the scales tipped or margined with black. The younger specimens 

 have a chevron-shaped black band crossing the back of the head, the point lying 

 on the parietal shields, and the ends passing just behind the angle of the mouth. 

 This is followed by a rather distinct narrow light nuchal collar, behind which are a 

 number of distinct narrow dark bands separated by much narrower light spaces. 

 On the posterior part of the trunk and on the tail are four indistinct, longitudinal, 

 dark stripes, two being dorsal and one along the middle of each side. The upper 

 surface of the head is dark brown. The upper lip and the lower surface are yellowish, 

 the anterior margins of the gastrosteges are brown, the brown line being widest at 

 the outer ends of the scales. The markings are most distinct in the younger speci- 

 mens. The older ones are nearly uniform olive above, and yellowish beneath, 

 with only faint traces of the dark bars on the anterior part of the body and of the 

 lines on the posterior extremity. 



This species is very closely related to R. merremi. 



Type, C. M. No. 264; paratypes, C. M. Nos. 263, 265, 266, 267. 



The specimens belonging to this species form a part of the LeBoutelier Col- 

 lection presented to the Museum by Mrs. A. Marshall Bell, and are labelled as 

 from "the Sierras of Bolivia." 



Counts and Measurements. 



Anal 



Scale-rows 



Gastrosteges •. . . 



Urosteges 



Upper labials . ; 



Preoculars 



Postoculars 



Temporals 



Total length in mm. . 

 Length of tail in mm 



(No. 267 (f.) 



1/1 



17 



159 



52/52 



8(4.5) 



1 



2 



1,2 



243 



41 



