14 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 



sides of the neck, above and behind the shoulder small, granular, and some of them having a 

 minute pore. Scales of the back of moderate size, larger than in Fitzingerii, rhomboid, having 

 a rather prominent carina, and terminating in a distinct point. Scales of the under parts 

 smooth and rhomboidal. The posterior surface of the thighs is for the most part granular, but 

 a small portion near the groin is covered with larger imbricated scales ; to a much smaller 

 extent, however, than in Fitzingerii, and other species which possess this character. 



The general colour of the upper part of this species is a rich dark brown, with whitish 

 transverse bands and spots, having a black margin. I have figured in fig. 2, of Plate VL, a 

 remarkable variety in which the bands are alternate black and white, and a broader and a 

 narrower longitudinal fascia of a yellowish-white colour, run the whole length of the body on 

 each side. The under parts are yellowish-white, with dark or almost black spots ; under the 

 throat bluish-gray with white spots. 



DIMENSIONS. 



Inches. Lines. 



Length of tlie head 8 



of the body , 2 3 ' 



of the t.ail S 4 



Totallength C 5 



Length of anterior extremity 1 1 



of posterior extremity 1 4 



This species much resembles Pr. Fitzingerii in many of its characters, as 

 well as in its size. It may, however, be at once distinguished from it by the charac- 

 ter of the scales of the back, which in this species are very distinctly carinated, 

 of a rather elongated form, and pointed at the extremity ; whereas in the other 

 they are shorter, smaller, the carina is very slight, almost indistinct, and the pos- 

 terior extremity is obtuse. 



The tail in the larger figure of our plate is deformed, having been renewed. 

 The specimen figured at (2,) in the same plate, is so remarkably distinct in the 

 colours and marking, as to lead me to suppose that it may possibly be a different 

 species. 



Proctotretus Darwinii. 



Plate VII.— Fig. 1, 2. 



Corpore subdepresso ; capita squamis numerosis, parvis, subelevatis, IcBvibus non imbri- 

 catis ; aurium margine anleriore integro ; temporibus colloque granulatis ; serie 

 unicd squamarum supralabialium ; facie posteriore femorum partim granulosa, 

 partini squamis imbricatis tectd. 



Habitat, Bahia Blanca, Northern Patagonia. Mr. Darwin. 



