REPTILES. 15 
are either bluish, reddish, or else of a metallic green, especially on the neck. The upper sur- 
face and sides of the head are spotted with different shades of black, or dotted with yellow and 
black. The occipital region and the back, in the male, occasionally exhibit sinuating black 
lines upon a brownish ground, which itself bears bluish, greenish, or slate-colored spots. Be- 
neath, the ground-color is whitish, vermiculated, maculated or clouded with greyish lines, 
spots, or dots. That region sometimes is unicolor in the female. 
This species appears to be quite abundant in the vicinity of Santiago, Chile, whence numer- 
ous specimens were obtained and preserved. 
Plate XX XVIII, fig. 1, represents a profile view of the female sex of Proctotretus tenuis, 
size of life. 
fig. 2, is an under view, showing the structure of that region. 
fig. 3, is an upper view of the head. 
fig. 4, a side view of the head. 
Figs. 2, 3, and 4, are slightly magnified. 
PROCTOTRETUS FEMORATUS, Girard. 
Pirate XL, Figs. 5—12. 
Spec. cHAR. Cephalic plates,rugose. Auricular aperture moderate, provided with an arched 
plate upon its supero-anterior margin, and one or two conical scales beneath and upon the 
same anterior margin. One series of supralabials. Temporal shields well developed, imbri- 
cated and carinated. Sides of neck with but one inconspicuous fold, and covered with small 
carinated scales. Dorsal scales large, carinated, posteriorly acute, and diminishing in size 
towards the sides. Abdominal scutellee smooth and entire. Posterior surface of thighs granu- 
lar. Tail elongated and slender. Brownish, with two parallel light vitte on either side, and 
two series of black spots. Abdomen whitish, unicolor; inferior surface of head with greyish, 
irregularly broken lines. 
Syn. Proctotretus femoratus, Grp. Proc. Acad. Nat. Sc. Philad. VII, 1854, 227. 
Descr. This species has the same slender aspect as P. tenuis, the limbs and tail being devel- 
Oped nearly in the same proportions. The body, mayhap, is a little shorter, and more slender 
still. The tongue and teeth present the same general shape and structure. The head is 
depressed, and quite declive from the frontal region towards the snout. Viewed from above, it 
is subtriangular, subtruncated anteriorly. The cephalic plates are of moderate development ; 
exhibiting upon their surface sinuating, subtubercular ridges, which give to that region a 
rugose appearance. The vertical, a pair of post-occipitals, and two pairs of postfrontals may 
be distinguished, amid their number, as the largest. Three postinternal surocularies hold the 
same relations towards their analogues as the former; a concentric chain being observed upon 
the inner margin of the surface of the upper lid. The perforation of the nostrils takes place 
through one single plate more towards its posterior or inferior edge than the anterior. The 
loral region being considerably reduced by the declivity of the frontal region, there are but 
one or two loral plates. The suborbital chain is composed of three narrow and elongated 
plates, provided internally with a conspicuous and sharp ridge or crest; the longest occupying 
the inferior rim of the orbit and the other two its anterior rim; whilst the posterior rim is 
formed by the anterior temporal plates. The surciliary ridge is composed of five or six obliquely 
superposed plates, smallest posteriorly. The surface of the lids is granular; their margins 
being provided with a series of very small plates. The rostral is transversally elongated and 
