HEEPETOLOGY OF JAPAN. 411 



temporals 2 + 8, only slightly differentiated from the adjacent scales; 

 seven supralabials, third and fourth largest and entering eye, first as 

 wide above as below ; seven lower labials, of which the first pair behind 

 the small mental does not reach the edge of the lip, the labials from the 

 third backward very low, only the first three in contact with chin- 

 shields, of which only the anterior pair is clearly differentiated, the 

 posterior being represented by two scales separated by one of nearly 

 the same size; 23 rows of smooth scales without apical pits; 205 ven- 

 trals, on the posterior half of the body by a median blunt keel and a 

 corresponding notch in the posterior edge of each scute; anal divided; 

 40 pairs of subcaudals. Color (in alcohol) bluish gray, darker above, 

 paler underneath,with 43 dark brown rings around the body and seven 

 on the tail, the bands being widest on the median line of the back, viz, 

 about 3^ scales wide, and there separated by a pale interval only two 

 scales wide; the rings are about 2^ ventrals w^ide on the underside and 

 the light intervals about the same width; head uniform dark brown, 

 with a yellowish horseshoe-shaped mark, the convexity of which rests 

 on the prefrontals extending backward on the outer edge of supra- 

 0(^ulars, upper postocular and upper temporals to and joining the first 

 pale cross line on occiput a scale row behind the parietals; snout and 

 labials dark brown like the rest of the head. 



Dimensions. 



mm. 



Total length 582 



Snout to vent 507 



Vent to tip of tail "5 



The young (in alcohol) are of a light bluish gray with blackish 

 brown rings and markings. The latter as the snake grows larger 

 become lighter and the former tlarker and brow^ner, while the demar- 

 cation between them becomes more obscure until in very large speci- 

 mens the markings become almost obliterated. In the larger speci- 

 mens therefore the dark gray cross markings correspond to the whitish 

 cross markings in the j^oung. 



This species grows to a considerable size. The largest specimen in 

 our collection (No. 5546) measures 1,097 mm. in total length, with a 

 tail 136 mm. long, while the type measures, respectively, 1,118 mm. 

 and 140 mm. 



Variation. — There is very little variation in the scale formula proper, 

 for only in one specimen (No. 5546) have I seen 4 temporals on one 

 side, the normal number of 3 occurring on the other. In eastern speci- 

 mens the number of ventrals is rarely as low as 188, but ranges usually 

 between 197 and 212, while the subcaudals vary between 32 and 43 

 pairs. Sometimes anomalies are found in the internasals; thus in 

 No. 106 of the Imperial Museum, Tokyo, there is a small unpaired 

 shield behind the detached part of the rostral, broadly in contact 

 with it and with the unpaired median prefrontal, and in our No. 7515 



