HERPETOT.OGY OF JAPAN. 



423 



onal, slightly longer than its distance from rostral, shorter than 

 parietals, half as wide as long, wider than supraoculars; parietals as 

 long as frontal and prefrontals together; noloreal; one preocular; one 

 postocular; one large anterior temporal; 7 supralabials, second in con- 

 tact with prefrontal, third and fourth entering eye, sixth very small; 

 3 lower labials in contact with anterior chin-shields; posterior chin- 

 shields nearly as large as anterior, separated by a small scale; 25 rows 

 of smooth, imbricate scales 

 round the neck, 35 rows 

 round the middle of the 

 body, the scales on the body 

 being imbricate and pro- 

 vided with a short keel 

 which reaches neither base 

 nor tip of scale; about 340 

 ventrals which often are so 

 reduced as to be distin- 

 guished with difficulty from 

 the scales, each ventral with two incomplete keels; anal divided, with 

 an elongated smaller shield on each side; 40 subcaudals; terminal scale 

 of tail small, only differentiated on. one side. Color (in alcohol) 

 above cinereous, white below, with 50 blackish rings round the body 

 and 5 on the tail; head black with superciliary region and snout 

 irregularly paie, the posterior supralabials being likewise light colored 

 with a brownish tinge. 



Dimensions. 



Head very small; neck and anterior part of body very slender, increasing in thick- 

 ness backward, the greatest height of the body being nearly 4 times the diameter of 

 the neck. mm. 



Total length 1, 125 



Snout to vent ], 027 



Figs. 345-347.— Disteira. melanocephala. nat. size. 

 345, TOP OF head; 346, side of head; 347, underside 

 OF head. No. 14, Imper. Mus. Tokyo. 



Vent to tip of tail 



Width of head 



Diameter of neck 



Greatest height of body. 

 Greatest height of tail . . 



98 

 15 

 11 

 42 

 26 



The male is relatively much slenderer posteriorly. 



Adult male; Imperial Museum, Ueno Park, Tokyo, No. 29; Oki- 

 nawa shima, Riu Kiu Archipelago (figs. 348-350). Rostral nearly as 

 high as broad, somewhat projecting, the portion visible from above 

 longer than interprefrontal suture; nasals long, the suture between 

 them twice as long as the one between the prefrontals, nostrils semi- 

 lunar close to the outer posterior angle; frontal long and narrow, the 

 length equaling distance from tip of snout and length of parietals, the 

 width at the middle equaling that of the supraoculars; parietals long, 



