62 HETERODON. 



much greater than in any other species : the 6th highest, centre of 

 eye over the junction of the 5th and 6th. 



Dorsal rows of scales 23, outer row smooth, rest all distinctly cari- 

 nated, the keels extending to the ends of the scales; those just be- 

 hind the occipital plates truncated, with obsolete carinas. Scales on 

 the hind part of the body rather broader and shorter than anteriorly ', 

 the inequality scarcely evident in large specimens. 



Ground-color light brown, or yellowish gray, with about 50 dorsal 

 blotches from head to tip of tail; the 39th opposite the anus. These 

 blotches are quite small, rather longer transversely, subquadrate, or 

 rounded, indistinctly margined with black, (obsoletely on the out- 

 side) ; they cover 7 to 9 scales across, are 2 to 2 J long, and sepa- 

 rated by interspaces of 1 J scales, which are pretty constant through- 

 out, though rather narrower on the tail. On each side of the dorsal 

 row may be made out, under favorable circumstances, four alternat- 

 ing rows of blotches ; the first on the contiguous edges of the scales 

 of the first and second exterior dorsal rows ; the second on the scales 

 of the 3d row, and the adjacent edges of those in the 2d and 4th ; 

 the third on the scales of the 4th, 5th, and 6th, and the adjacent 

 edges of the 3d and 7th ; and the fourth on the scales of the 6th, 

 7th, and 8th rows, and the adjacent edges of those of the 5th. This 

 last is opposite the intervals of the dorsal series ; the rest alternate 

 with it. The central inferior surface of the abdominal scutcll^ is 

 black, sharply variegated with quadrate spots of yellowish white ; 

 the portion of the scutellce entering into the side of the body is yel- 

 lowish white, with that part opposite the dorsal intervals dark brown, 

 thus, in fact, constituting a fifth lateral series of blotches, alternating 

 with the lowest already mentioned. The throat and chin are un- 

 spotted. The head is light brown, with a narrow whitish line finely 

 margined before and behind with black, which crosses in front of the 

 centre of the vertical, and through the middle of the superciliaries : 

 a second similar but more indistinct line runs parallel to this, jus* 

 behind the rostral, and ^extending down in front of the eye. A third 

 equally indistinct and similar line crosses the posterior angle of the 

 vertical, and runs back on the side of the neck, behind the labials 

 and temporal shields. There is a broad brown patch from the back 

 part of the eye to the angle of the mouth, across the penultimate and 

 last labial. The coloration is thus very diiferent from that of //. 

 simns, where there is a distinct narrow black band across the fore- 

 held scarcely involving the vertical, and passing through the eye to 



