ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 
2 
Thus of the species now described two were known to Weigmann, and de- 
scribed by him, namely, Chileusis, and nigromaculatus. I received from Capt. 
K ing, Chilensis, pictus, cyanogaster, Kingii, Fitzingerii, and, from other sources, 
Chiletisis, pictiis, Weigmcmnii. Bibron describes the whole of these, excepting 
Kingii, and in addition to them tenuis, pectinatus, signifer. In Mr. Darwin’s 
collection are found all those described by Bibron, excepting signifer; and in 
addition Kingii now first described, and the following species never before 
observed, namely, Dartvinii, gracilis, Fihronii. 
Although the form of the whole of the species much more nearly approximates 
that of the Agamidae than most others, they are far removed from that family by 
several important characters, which it is unnecessary here to detail. 
Proctotretus Chilensis. 
Plate I. — Fig. 1. 
Aurihus margine anteriore dentato; collo non plicato ; squamis dorsi magnis, rhom- 
heis ; acuth carinatis ; serie unicd squamarum supralabialium. 
Calotes Chilensis, Less, et Gain. Voy. de la Coqullle, Zool. Rep. t. i. f. 2. 
Tropiduriis Chilensis, Weigm. Act. Acad. Gees. Leop. Carol. Nat. cur. xvii. pp. 233. 268. 
Proctotretus Chilensis, Bilir. Hist. Nat. des Rep. IV. p. 269. 
Sun. Tropiduriis nitidus, Weigm. 1. c. p. 234, t. xvii. f. 2. 
Var. Tr, olivaceus, Ib. 1. c. p. 268. 
Habitat, Guasco in Northern Chile. 
Description. — Head short and broad, rostrum rounded, obtuse. Scales of the head large, and 
slightly raised, separated by distinct grooves. Superciliary ridge strongl}" marked, forming a 
distinct carina, composed of five or six narrow, elongated, obliquely imbricated scales. Nostrils 
large, nearly round. A single series of narrow scales between those of the upper lip and the 
orbit. Scales of the temples imbricated, rhomboidal and carinated. The opening of the ear 
oval, rather large, furnished anteriorly with three or four projecting scales, of which the upper 
one is the largest. The neck is short, robust and I’ound, and without any lateral fold ; in 
which it differs from every other species of the genus. The trunk is thick, rounded on the 
back and sides, flattened beneath, diminishing toward either extremity. The tail is ordinaril}'^ 
almost twice as long as the body, thick at its origin, and tapering regularly to the extremity, 
nearly round, excepting near the base, where it is slightly quadrilateral. The anterior feet 
when placed against the sides, extend backwards little more than mid-way between the 
shoulder and the groin ; the posterior ones, stretched forward, reach the arm-pit. 
The scales of the whole upper and lateral parts of the body, tail, and limbs, are loosely 
imbricated, large, rhomboidal, and furnished with an elevated carina, terminating in an acute 
point : those of the under parts are large, smooth, and obtuse. 
