26, PROCTOPORUS. 413 
parietal narrower and a little shorter than parietals, pentagonal, 
hardly wider posteriorly than anteriorly, once and a half as long as 
broad ; three subequal occipitals ; three supraoculars ; a loreal and 
afrenoorbital ; a row of very small infraorbitals ; temples irregularly 
shielded ; chin-shields, one anterior and four pairs, the first two 
pairs entirely, the third anteriorly, in contact; gular scales sub- 
quadrangular, those in contact with the chin-shields a little larger ; 
about twelve transverse rows of scales between the chin-shields and 
the edge of the collar; about ten collar-shields. Nuchal scales 
very small, round ; dorsal scales narrow, quadrangular, feebly keeled 
or striated, the transverse series interrupted on the median dorsal 
line; a lateral line of granular scales betweeu the dorsals and ven- 
trals ; fifty-four scales between the occiput and the base of the tail, 
fourteen of which are anterior to the fore limbs. Ventral plates 
quadrangular, in twelve longitudinal and twenty-six transverse 
series. A pair of anterior preanal shields, and a second row of six 
narrow elongate shields, with a small triangular one wedged in 
between the median pair posteriorly. Limbs with smooth shields. 
Females with two or three femoral pores on each side. Tail thick, 
covered with scales like those of the body. Dark brown above, 
bluish grey inferiorly, dotted with darker. 
millim. millim. 
Total length (tail broken) 87 From end of snout to 
OGG esscarerpe ge SS eG 12°5 VElUb shania ataas ors 58 
Width of head ........ i Orem Oy eon aie gee tis 13 
From end of snout to fore Hand. Mites wsecakaces o 17 
Nim <s-vares ese wees 17°5 
Chanchamayo River, eastern slope of the Peruvian Andes. 
2. Proctoporus unicolor. 
Riama unicolor, Gray, Proc. Zool. Soc. 1858, p. 446, pl. xv. fig. 2. 
Proctoporus pachyurus (non Tsch.), Giinth. Proc. Zool. Soc. 1859, 
89 
Hisleonos (Proctoporus) unicolor, Peters, J. ce. p. 223. 
This species differs from P. pachywrus by the still more elongate 
body and weaker limbs, the less depressed head, the shorter snout, 
and in the following points :—Interparietal hexagonal, considerably 
broader posteriorly than anteriorly, longer than parietals ; a median 
occipital is frequently absent, and, if present, is very small; no 
loreal; temporal shields larger; only the two anterior pairs of chin- 
shields in contact; they are followed by several large similar shields, 
the median pair resembling an additional pair of chin-shields ; collar- 
shields more elongate, eight or nine. Nuchal scales much larger 
and more quadrangular; thirty-seven to forty-four scales from occi- 
put to sacrum inclusively ; thirty-six to thirty-eight scales round 
the middle of the body ; twenty-three to twenty-six transverse rows 
of ventrals. Praanals five or seven, a small pair anteriorly, three 
or five elongate shields forming a second row. Males with nine to 
