REPTILES. 
7 
small interrupted fascia of the same colour extends from the shoulder to the thigh. The 
belly is of an uniform dirty white. 
This species approaches considerably to Pr. cyanogaster in general form and habit, and in 
many of its characters ; but it may be at once distinguished from it not only by its colouring, 
but by the absence of even the slightest appearance of a carina on any of the scales of the 
temples or of the sides of the neck. 
DIMENSIONS. 
Inches. Lines. 
Length of the head 0 6 
of the body 1 6 
of the tail 3 4 
Total length 5 6 
Length of anterior extremity 0 7 
of posterior extremity 1 1 
Found by Mr. Darwin at Port Desire, in Patagonia. 
Proctotretus tenuis. 
Plate III. — Fig. 2. 
Capite squcvmis IcBvihus, non imhricatis ; aurihus magnis, margiue anteriore sub- 
iuherculato ; serie miica squamarum supralabialium ; temporibus sqiiamis rotun- 
datis, imbricatis ; collo granulosa ; sqiiamis dorsi parvis, obtusis, carinis minimis ; 
squamis lateralibus exiguis, non imbricatis; facie posteriore femorum omnind 
granulosa. 
Proctotretus tenuis, Bibr. 1. c. p. 279. 
Description. — General form slender: head rather short and obtuse, covered with flattened smooth 
scales ; anterior margin of the ears with one or more slight tubercles ; temples covered with 
rounded imbricated scales, some of which are slightly carinated; sides of the neck, and 
above the shoulders granular ; scales of the back small, slightly carinated, obtuse ; those of 
the sides very small, very little imbricated ; those of the belly small and smooth. The 
posterior surface of the thighs has no patch of imbricated scales, but is wholly granular. 
The colour of the two specimens brought home by Mr. Darwin is so much obliterated, 
that I am obliged to have recourse to the account given by Bibron of the colour and markings 
of this species : — “ Les deux sexes du Proctotrete svelte n’ont pas le meme mode de coloration. 
Ni Tun ni I’autre ne portent, de chaque cote du dos, une bande longitudinale verte ou jaunatre 
comme cela s’observe dans I’espece precedente, {Pr. pictus.) 
“ Le male a le dessus de la tete nuance de brun et de fauve, ou bien ponctue de jaune 
et de noiratre. La region cervicale est, ainsi que le dos, vermiculee de noir sur un fond brun. 
