41. SONORA 867 
Description—Head wide, with flattened top and rather 
narrow but not greatly depressed snout. Temporal regions 
not swollen, but head a little wider than neck. Rostral 
prominent, broad, high, rounded in profile, projecting con- 
siderably beyond lower jaw, hollowed below, not much re- 
verted on top of snout, and bounded behind by internasal, 
nasal and first labial plates. Plates on top of head are a 
pair of internasals, a pair of prefrontals, a frontal, supra- 
ocular of each side, and a pair of parietals. Anterior and 
posterior nasals usually united into a single plate. Loreal 
often quite small. One preocular. Two postoculars. Tem- 
porals one followed by two, rarely 1+1. Supralabials 
normally seven, sometimes six, third and fourth reaching 
eye, sixth largest. Inferior labials six or seven, second 
small, fourth largest, first pair meeting on median line be- 
hind the small triagonal mental. Genials in two pairs, the 
posterior very small. Scales on body smooth, in fifteen rows. 
Anal plate divided. Gastrosteges in western specimens vary- 
ing in number from 157 to 183. Urosteges in two series of 
from 44 to 57. 
The head is pale yellowish brown or orange, with or 
without a definite or indistinct large dark brown blotch on 
the parietal and frontal plates. A light vinaceous rufus, 
pink, or orange band extends along the back from the occi- 
put to the tip of the tail. This band is about four or five 
scales wide on the body, and two or three on the tail. The 
scales of the central two or three rows usually show only 
very faint darker markings, but those of the more lateral 
rows are marked each with a central dash of dark hair brown, 
while their margins are whitish. These dark dashes there- 
fore appear as a brown line along the middle of each row 
of scales, with the exception of a few of the dorsal rows, 
while the ground color is reddish or pink dorsally and white 
laterally. The reddish dorsal band may be rendered less 
