198 BULLETIN 58, UNITED STATES NATIONAL MUSEUM. 



Dimensions. 



mm. 



Total length 186 



Snout to vent 64 



Vent to tip of tail 122 



Snout to ear-opening 15 



Greatest width of head 12 



Axilla to groin 34 



Foreleg 18 



Hind leg 25 



The female difTers in lackins; the swellino; at the ])ase of the tail and 

 apparent!}' also the dift'erentiated keeled scale l:)ehind each corner ol 

 the vent. 



The younger individuals differ in not havin<j!; the temporal region 

 swollen and also differ greatly in color. As exemplified by a large 

 series from Mount Fuji, they are (in alcohol) nearly blackish brown 

 above, becoming dark brownish slate on the terminal half of the tail, 

 with five pale longitudinal stripes, viz, one median; one on each side 

 proceeding from the outer edge of the supraoculars down the sides of 

 the back, two scale widths from the median stripes ; finally, a lateral 

 stripe on each side originating on the supralabials, through the ear and 

 above both fore and hind legs; all continued on the tail where they 

 gradually disappear; the median stripe bifurcates on the interpa- 

 rietal, each branch following the outer edge of the frontal to the 

 snout, which is pale brownish; underside bluish gray, except chin, 

 throat, limbs underneath, anal plate, and the subcaudal transverse 

 plates, which are pale buff'. According to Stimpson they are black 

 in life with light blue stripes and pale blue" underside. 



Variation. — There is considerable variability in the head scales anil 

 their various relations, but as it would be of little use to note all the 

 deviations from the specimen described above, it will be sufficient to 

 call attention to those which are of systematic value. 



Out of 62 specimens examined by me only one (No. 34123) has the 

 azygous postmental divided, and the abnormality of the specimen is 

 further shown by a small portion of the side of the posterior post- 

 mental being also separated by a suture. 



In 3 specimens (Nos. 34120, 34130, 34138) the posterior loreal 

 is in contact with three supralabials on both sides; in one (No. 30734) 

 on one side only, and in one (No. 34126) it barely touches the third 

 labial on one side. 



Five specimens (Nos. 34119, 34121, 34126, 34127, 34133) have no 

 postnasal at all; two lack it on one side only (Nos. 34128, 34139), 

 while in 37 specimens it is present on both sides. 



Curiously enough the variation in the postnasal is most pronounced 

 in a single series of specimens collected near Mount Fuji in September , 

 1898. Out of the 21 specimens five have no postnasals at all, two on 



