PROCTOTRETUS PECTIXATUS. 333 



and occasionally blended together. The space between these brown 

 spots is of an emerald-green in adult individuals : a tint which is 

 liable to turn into blue by immersion in alcohol. The upper surface 

 of the limbs is irregularly spotted with brown. The sides of the neck 

 is mottled with rusty yellow and blackish-brown. Beneath, the color 

 is of a uniform white or dull yellow. 



LOG. Specimens of this species were collected on the banks of the 

 Rio Negro, in Patagonia, being quite abundant among the sandhills. 

 A colored sketch of one of them was made, at the time, by Mr. 

 Drayton. 



Plate XIX, fig. 1, represents Proctotretus splendidus, in profile, and 

 size of life. 



Fig. 2. exhibits the inferior surface of the same animal. 



Fig. 3, the upper surface of the head ; 



Fig. 4, a front view of the same. 



Fig. 5, the left hand, from above. 



Fig. 6, a group of dorsal scales ; 



Fig. 7, a group of abdominal scales. 



Figs. 3-7, are somewhat magnified. 



2. PROCTOTRETUS PECTINATUS, Dum. & Bibr. 



SPEC. CHAR. Labial plates exceedingly narrow and elongated ; one 

 series of supralabials. Auricular aperture moderate, with two or 

 three erect scales in front. A pectinated crest on each side of the 

 body, formed by somewhat narrower and more erect scales. Grey- 

 ish-fawn above, with three series of large, ovate, blackish, white- 

 margined spots. The pectinated crest is white. Three yellowish 

 or whitish streaks across the head. Beneath white. 



Sr.v. Proclolretus pectinatus, DuM. & BIBR. Erpet. gen. IV, 1837, 292. GUICH. 

 in Gay, Hist, de Chile, Zool. II, 1848, 44. 



Liolaemus (Proctotretus) pectinatus, FITZ. Syst. Kept. I, 1843, 74. 



OBSERV. This species, though closely allied to the preceding one, 

 will appear sufficiently distinct from it, since there is but one pecti- 



84 



