REPTILES. 227 



Ops. Tlie species of this genus may he arranged into two groups, according to the number 

 of longitudinal series of abdominal scutellas, some having eight, the others ten of such series: 

 the species described below belonging to the latter groiip. 



CNEMIDOPHORTJS PEiESIGNIS, B. & G. 

 Plate XXXVIII, Figs. 1—5. 



Spkc. char. Abdominal scutellfe disposed upon ten longitudinal rows; dorsal scales very mi- 

 nute. Postsubgular fold provided with small plates upon its edge. Ground-color greenish, 

 blotched with black, and exhibiting laterally two narrow^ light vittje. 



'"v CnemidopJwrus prcesignis, B. & Gr. Proc. Acad. Nat. Sc. Philad. VI, 1852, 129. 



iJBBCR. The head, which is contained twice and three-fourths of a time in the combined length 

 of the neck and body, is subpyramidal in shape, slightly arched upon the occiput. The plates 

 which cover its upper surface are well developed. The vertical is hexagonal, broadest ante- 

 ■.-■ - ■■" "^ is preceded by a pair of postfrontals, narrowest upon the line of their junction, dilated 

 ■J': and rounded upon the latter margin. A large and unique prefrontal occupies nearly 



.le width of the snout, being irregularly octagonal in its outline, touching posteriorly the 

 jL lis, exteriorly the loral and postnasal, and anteriorly the prenasals. The rostral oc- 



cupii -^ entire width of#ie snout, advancing in a conical form towards the prefrontal, Avhich, 

 however, it does not reach. The prenasal is elongated and subquadrangular, being slightly 

 curved backwards owing to its oblique situation on the sides of the snout, extending from the 

 margins of the labials to the upper surface of the snout, where it meets its fellow from the op- 

 posite side, separating entirely the rostral from the prefrontal. The postnasal is not quite as 

 high, though a little broader than the prenasal. It is anteriorly subconvex, and posteriorly 

 concave, exhibiting a portion of its surface in an upper view of the head. The nostrils are 

 large, situated at the inferior margin of the nasal plates, close to the labials, encroaching more 

 upon the prenasal than upon the postnasal. The loral is very large, its convex anterior margin 

 fitting the concave one of the postnasal. It is broadest anteriorly, and three-sided, offering 

 points of contact to a surciliary and two anteorbitals, the lowermost being the largest, angu- 

 lar, and five-sided, whilst the upper one is elongated and narrow. There are two suborbitals, 

 the anterior being twice as large as the posterior one. The postorbitals are numerous, small, 

 and polygonal. Four surocularies and six surciliaries constitute the upper roof of the eye, the 

 surciliaries forming a prominent ridge, between which and the surocularies a series of small 

 scales may be observed, extending from the anterior margin of the second suroculary and pos- 

 terior margin of the second surciliary backwards, enclosing the posterior oiitline of the surocu- 

 laries halfway between the third of the latter group and the anterior occipitals. The anterior 

 three surciliaries are much longer than the posterior three. The eyelids, upper and lower, are 

 densely covered with small scales, the largest of which constituting a row along the inner mar- 

 gin of the orbitals. On the edge of the lids is another series more conspicuous than upon the 

 intervening space. The middle surface of the lower eyelid is provided with a horizontal series 

 of five or six quadrangular plates; the latter being higher than long.' The occipitals are seven 

 in number, the anterior two being somewhat larger than the others, broadest upon their poste- 

 rior half, and in contact anteriorly with the vertical. The posterior five are disposed ujjon a 

 sublinear and transverse row, the central one being placed immediately behind the middle line 

 of the anterior two; the adjoining two, the largest of the five, are in contact anteriorly with 

 the first pair of occipitals; the exterior two occupy a somewhat retreated situation along the 

 external margin of the internal pair. An area of small plates surrounds posteriorly and exteri- 

 orly the postoccipitals. From the posterior extremity of the surciliary ridge to the upper mar- 



