214 BULLETIN 17 7, UNITED STATES NATIONAL MUSEUM 



sides to appear very finely striped with oblique black stripes; a wide 

 light middorsal stripe involving the crest and a rather faint light 

 lateral stripe from axilla to groin; these stripes are due to the absence 

 of the black outer mark on the scales of the region in question; top 

 of head to occiput vandyke brown; sides of head, snout, and throat 

 black, this shade continuing unbroken past the ear to the origin of 

 the shoulder fold; traces of three chevron-shaped black bars across 

 the nuchal region; limbs without definite bars but with some black- 

 centered scales; tail with very faint suggestions of wide dark vertical 

 bars; entire ventral surface immaculate pale china blue, except for 

 the black throat; some of the scales on lower parts of sides, limbs, 

 and tail white-centered. 



Variations. — The head plates of this species do not appear to vary 

 much in rugosity or in arrangement. They are always ridged, the 

 occipitals rather coarsely, the supraoculars more finely and evenly, 

 and the frontals and prefrontals more lightly. There is a median 

 series of scales on top of the snout, separating the prefrontals from 

 the corresponding scales on the other side. The first one of this 

 median series appears as a small scale sometimes touching the rostral 

 and separating the supranasals entirely from each other. Next come 

 one or two single scales, and finally a pair of scales side by side, or 

 sometimes a little group of four or five scales. In every one of my 

 specimens I find three scales between the rostral and the beginning 

 of the supraorbital ring. These are separated from the canthals 

 posteriorly by a wedge-shaped scale in almost every instance; in the 

 described specimen there is a contact on one side of the head only. 

 The supraoculars are normally six in number; sometimes five or seven 

 are found. In the largest male at hand, U.S.N.M. No. 80775, which 

 measures 77 mm. from snout to vent, the tail is 1.6 times the length 

 of the head and body. The variation here is from 1.5 to 1.8, with the 

 majority falling on 1.7. Subdigital lamellae on the fourth toe number 

 from 22 to 26, always tricarinate. The great irregularity of the rows 

 of body scales makes it impracticable to give definitely the range of 

 scales at midbody or in a longitudinal series. 



The adult males are all characterized by the conspicuous black 

 throat and face, the black area always extending considerably beyond 

 the ear — in fact, it reaches halfway to the shoulder, involving the 

 shoulder folds. Frequently on young males there is a light spot below 

 the eye and another in front of the ear, as well as a larger light patch 

 behind and below the ear. The top of the head is brown, sometimes 

 with faint minute darker spots emphasizing the ridges, sometimes with 

 the dark pigment concentrated in larger spots on the central frontal 

 region or on the inner borders of the supraoculars. The older males 

 give a decided impression of striping, with the wide light dorsal stripe 

 and the two lateral stripes and frequently an additional dorsolateral 



