Tribus—EUNOTES. Bibron.
Familia—TROPIDURIDÆ. Mihi.
Tropidolepidiens. Bibr.
Genus—Tropidurus. (In part.) Weigmann.
Proctotretus. Bibr.

Character Genericus.—Pori femorales nulli. Pori præ-anales in maribus tantùm. Cristâ dorsalis nulla. Dentes palatini. Squamæ imbricatæ; dorsales carinatæ.

The genus which I take the present favourable opportunity to illustrate, formed a section or sub-genus of the genus Tropidurus, according to Weigmann, who, however, was acquainted with two species only; Pr. Chilensis and Pr. nigromaculatus. Of the varieties of the former of these, that author has made no less than three species ; but these have been very properly reduced by M. Bibron to one only. The last-named excellent erpetologist described several additional species, which had been brought from Chile, by M. D’Orbigny, and others ; and I received, some years since, from Capt. King, three or four species which were found by him in the same locality, in the course of his well-known survey. The number of species altogether, hitherto known, amounts to ten; to which I have now the opportunity of adding four entirely new, forming part of the interesting collection of Reptilia made by Mr. Darwin. One of them, Pr. Kingii, was already in my collection, amongst those which were given me by Capt. King. The genus, therefore, of which, but lately, two species only were known, now consists of fourteen ; and it is highly probable that more may yet be obtained by more prolonged and extensive investigation in the same districts.

Thus of the species now described two were known to Weigmann, and described by him, namely, Chilensis, and nigromaculatus. I received from Capt. King, Chilensis, pictus, cyanogaster, Kingii, Fitzingerii, and, from other sources, Chilensis, pictus, Weigmannii. 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, Darwinii, gracilis, Bibronii.

Although the form of the whole of the species much more nearly approximates that of the Agamidæ than most others, they are far removed from that family by several important characters, which it is unnecessary here to detail.

Proctotretus Chilensis.

Auribus margine anteriore dentato; collo non plicato; squamis dorsi magnis, rhombeis; acutè carinatis; serie unicâ squamarum supralabialium.

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 strongly 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 round, 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 ordinarily 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.

This is one of the most beautiful species of the genus. The general form is robust and solid, forming a remarkable contrast with most other species of the genus. The surface is beautifully relieved by the fine, large and prominent scales, which are ranged in rows of perfect regularity, of which there are about eighteen on the back and side.

In colour and markings the individuals differ considerably; so as to have given rise to the opinion that they form three distinct species. Monsieur Bibron mentions two principal varieties, constituting the Tropidurus olivaceus and Tr. Chilensis of Weigmann. In the former, the colour is of a more or less bronzed bright green, or yellowish, according as the green or yellow colour prevails on the scales, each of which is green, with a border of yellow on each side: this border, according to M. Bibron, in some individuals of a blood-red colour. In some, especially in young individuals, there are several waved bands running transversely across the back.

In the second variety, says M. Bibron, the upper parts are either of an olive colour, with a golden glance in certain lights, or fulvous, with more or less of a yellow tint; and these have always four brown bands running the length of the body, appearing as if formed of a series of large spots united together. “The temples are marked with a black line, which extends from the posterior angle of the eye to the ear; another divides behind the occiput into two branches, which pass to the neck there to join the dorsal bands.” There are other variations of colour, but scarcely deserving to be considered as constituting permanent or fixed varieties; the largest and finest specimen I have seen, which I received from Chile, is almost uniformly of a fine metallic green, without any markings.

This species would appear to be very common in Chile, from the numerous specimens from that country in the museum in Paris, which were brought by M. Gay, and by M. D’Orbigny. I have also received specimens from Capt. King. I find only one or two specimens in Mr. Darwin’s collection, which he found at Guasco in Chile.

Corpore gracili: capitis squamis lævibus, non imbricatis: aurium margine anteriore minutè bi-tridentato: collo vix plicato, squamis imbricatis: serie unicâ squamarun supralabialium: femorum facie posteriore omninò granulosâ.

Habitat, Port Desire, Patagonia. Mr. Darwin, MS.

Description.—This new species is more slender and graceful in its general form than any other of the genus, not excepting Pr. tenuis, which in its general proportions it considerably resembles. The head is rather short, the anterior portion including the eyes being nearly an equilateral triangle. The muzzle is rounded. The scales of the head flat, rather large, consisting behind the nose of three series of 2, 3, 3, and 2, mostly hexagons. The nostrils are small and perfectly round, the superciliary ridge is very slightly marked; there is but a single row of small linear scales between the labial and suborbitar. The ear is of moderate size, the anterior margin having two or three small projecting scales. The scales on the temples are imbricated and smooth; those of the sides of the neck also imbricated but very small. The neck is almost wholly without a fold, having merely a slight loose elevation of the skin. The scales of the back are small, rhomboidal, flat, the carina low, and not pointed at the extremity. They consist of about ten rows on each side of the median line. Those of the sides and belly are wholly without any notch on the free margin. The scales around the axillæ, and those of the posterior face of the thighs are granular. The tail is of considerable length, being more than twice the length of the head and body. The limbs are remarkably long; the anterior, when pressed against the side, reaching to the setting on of the thigh, and the posterior reaching forwards nearly to the ear. The general colour of the upper parts is greyish brown, with a yellow longitudinal fascia extending on each side from the upper edge of the orbit to some distance along the tail—and another from beneath the eye to the thigh. The middle of the back is lighter than the sides—beneath the second lateral line the colour fades, and on the belly it is pale buff or light yellow. The sides are dotted with black; and there are some dark waved lines and dots beneath the lower jaw.

This species is at once distinguished from every other by the fold of the neck being scarcely cognizable. It is however not so absolutely wanting as in Pr. Chilensis.

A single individual of this species was taken by Mr. Darwin at Port Desire.