62 HELLER 



above and on sides with imbricate, keeled scales about size of dorsal 

 tubercles ; covered interiorly with a median series of enlarged scales. 



Coloration in Life. Above pinkish-gray with dusky blotches and 

 spots; a median light pinkish stripe from nape to tail forking into 

 several faint narrow cross bars on back. Head lighter grayish with 

 irregular dusky blotches above, snout faintly dusky spotted, labials 

 more heavily spotted, a dusky stripe beginning at tip of snout, passing 

 through eye above ear opening and becoming obsolete on shoulder, 

 widest and most distinct just posterior to eye ; sides lighter, dusky, 

 spotted. In perfect specimens the tail is light like the head, the dark 

 cross-bands narrower than the light areas and anteriorly broken up 

 into spots. Limbs above barred and blotched with dusky. Under- 

 parts cream or whitish, the scales with minute dark dots. 



Variations. Longitudinal series of dorsal tubercles varying from 

 two to six, the tubercles in the outer rows often little larger than the 

 granules and only partly juxtaposed. Rows of ventral scales between 

 axilla and groins forty-four to forty-eight. Superior labials eight or 

 nine, inferior usually seven. One specimen has the internasals sepa- 

 rated by a median row of scales, in all the others they are contiguous. 

 Transverse lamella? under fourth toe twelve to fourteen. 



Coloration above varying from thickly dusky blotched with distinct 

 median light stripe to light grayish, faintly dusky shaded without evi- 

 dent light stripe and with dark stripe through eye almost obsolete. 



Young with the median dorsal light stripe beginning sharply at base 

 of head and extending to beginning of tail ; widening out into six 

 light cross-bars on back, the light areas narrower than the dark ones, 

 the latter splitting on the sides into short forks. Tail light grayish 

 with twelve wide dusky bars. Stripe through eye pronounced, extend- 

 ing to above shoulder. Top of head and snout dusky spotted. Limbs 

 above with oblique dusky bars. Under surfaces whitish, the scales 

 minutely dark spotted. 



This species is unique among those possessing keeled tubercles in 

 the possession of less than ten rows of dorsal tubercles on the dorsum. 

 Its derivation from a form possessing ten or more rows is evident as 

 shown by the ten rows on the sacrum. The shape and size of the 

 digital pallets and the median series of enlarged scales on inferior sur- 

 face of the tail ally it to P. tuberculosus from which it differs in the 

 size and number of rows of dorsal tubercles, the smaller size and 

 lighter coloration and in the absence of larger granules on the occiput 

 and limbs. 



Named for Dr. C. H. Gilbert, of Stanford University. 



