726 13. COLUBRIDZ 
Description——Head somewhat flat-topped or rounded 
with snout projecting and rather narrow. Temporal regions 
not swollen. Rostral plate very large, prominent not very 
narrow but often recurved between internasals on top of 
snout; bounded behind by internasal, anterior nasal, and 
first labial plates. Plates on top of head are a pair of 
internasals, a variable number of prefrontals (normally 
four), a frontal, supraocular of each side, and a pair of parie- 
tals. Anterior and posterior nasals usually distinct, some- 
times united. Loreal usually elongate. One or usually two 
preoculars; and three or four, usually three, postoculars. 
Tips of some labials may be cut off forming suboculars or 
loreals. Supralabials usually eight, sometimes nine or 10. 
Infralabials usually 13, sometimes 12 or 14. Temporals of 
first row varying from two to six, usually four. Genials 
in two pairs, anterior much larger than posterior. Scales on 
body in 29 to 37 rows, usually 33 or 31, keeled except in a 
varying number of rows on each side. Anal plate not di- 
vided. Gastrosteges varying in number from 223 to 263, 
males having from 224 to 252, females from 223 to 263. 
Urosteges in two series of from 50 to 72, males having 
from 58 to 72, females from 50 to 67. 
The ground color is pale yellow or grayish yellow, some - 
times more or less obscured by the spreading of the blotches 
or the presence of dark keels on the scales, especially later- 
ally and anteriorly. Along the middle of the back, from 
the head to a point over the anus, is a series of from 46 to 
66 (average 55) dark brown blotches. These blotches may 
be blackish or actually black on the neck and toward the 
tail, and may be more or less margined with black through- 
out. On the upper surface of the tail are from 12 to 21 
(average 15.4) dark brown or black blotches or cross-bars. 
The dorsal blotches on the anterior part of the body may 
be rounded, but they soon become more or less quadrate 
