90 SYNOPSES AND DESCRIPTIONS. 
of small yellowish spots; front part. of the snout crossed by a yellowish 
band; a black spot on the lips below the eye; uniform yellowish below. 
(From descr.) Mexico. 
Contra. 
Baird & Girard, 1858. 
Moderately elongate, sub-depressed; head little larger than the neck, 
depressed; tail short, tapering to a point. Eyes small, pupil round. 
Crown-shields normal. Muzzle protruding. Rostral convex, broad. Nasal 
entire or divided. A loreal, sometimes united with other shields. One 
anteorbital. Generally two postorbitals, sometimes one or three. Tem- 
porals commonly 1+-2. Labials seven (6—7). Infralabials seven (6—8). 
Seales smooth, rarely keeled, in 15 series. Anal bifid. Subcaudals in two 
rows. 
(Sonora.) 
Colors in transverse bands; 
ventrals 149; bands 31 semiannulata. 
ventrals 158; bands 41 occipitalis. 
ventrals 158—167; bands 31 isozOnd. 
scales keeled on the tail aemula, 
(Contia.) 
Colors not in transverse bands; 
oculars 1—2; 
labials eight; nasal grooved; 
scales slightly keeled at the tail pygaed. 
labials seven; flank with longitudinal band ; 
scales smooth; 
entrals about 161, with black bases 
mitis. 
ventrals about 145 episcopus. 
CoNnTIA SEMIANNULATA. 
Sonora semIANNULATA Baird & Girard, 1853, Cat. N. A. Serp., 117. 
Body subcylindrical, moderate; head not very distinct from neck, nar- 
rower on the snout, muzzle produced, elongated; tail short, about one 
