12 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 



Var. C. Le dessus du corps est uniformement peint d'un vert olive. Le dessus du cou, Ie 

 milieu de la poitrine et celui du ventre sont d'un noir profond. 



DIMENSIONS. 



Inches. Lines. 



Length of the head 7 



of the body 2 8 



of the tail 4 2 



Total length .... 7 7 



Length of anterior extremity 1 2 



of posterior extremity 2 



This species agrees with Pr. Darwinii and Weigmannii, and in some degree 

 with Pr. Kingii, in having a portion of the posterior face of the thighs covered 

 with imbricated scales. This is a character, which although existing in all those 

 which I have named, is found to obtain in very different degrees ; in TV. Weig- 

 mannii being very distinctly marked, and in TV. Kingii very slightly so, and in 

 some specimens scarcely notable. It is probable, that var. B., and possibly A. 

 also, of Mons. Bibron, may be Pr. Kingii ; but I have not had the opportunity of 

 ascertaining this from the actual examination of the specimens. 



Found by Mr. Darwin at Port Desire, and at Santa Cruz, in Patagonia. 



Proctotretus cyanogaster. 



Plate V.— Fig. 2. 



Squamis capitis neque imbricatis nee carinatis ; temporum imbricatis, subcarinatis, 

 margine rotundato ; aurium margine anteriore simplici ; squamis dorsalibus rhom- 

 beis, laxis, carina postice acuta ; femorum facie posteriore omnind granulosa ; 

 corpore supra olivaceo, fascia utrinque longitudinaliflavescenti; abdomine cceruleo. 



Proctotretus cyanogaster, Bibr. 1. c. p. 273. 



Habitat, Valparaiso, and Valdivia, Chile. 



Description. — It has been well observed by M. Bibron that this species offers at first sight some- 

 what the general aspect of the genus Algira ; the acute points of the dorsal and lateral scales 

 and the general form giving very much that appearance. 



The head is of moderate size, somewhat deflexed ; the scales moderate, flat and smooth ; 

 those of the temples are slightly carinated, imbricated and rounded : those of the sides of the 

 neck small, not granular, but rhomboidal and imbricated. There is but a single series of oblong 

 scales between the labial ones and the orbit. The margin of the ear is entire and simple ; the 



