OF 
SYNOPSES AND DESCRIPTIONS. 123 
blotches of brown or black, separated by narrow spaces of light color. 
Lower surface yellow, somewhat clouded posteriorly. Head spotted with 
dark on the parietal region, with a transverse band of dark in front of the 
supraciliaries through the eye to the hinder labial. Description from Bra- 
zilian specimens. Species said to occur in Southern Mexico. 
var. STENOPHRYS. 
LACHESIS sTENOPHRYS Cope, 1875, Batr. and Rept. Costa Rica, 152. 
Muzzle short, depressed; rostral an equilateral triangle. Crown-scales 
flat, hexagonal, faintly keeled. A trapezoid plate in front of the large 
superior preocular. Four rows of scales between labials and orbits. 
Labials nine, third largest, second low and not bounding the pit. Pit 
bordered by three plates; upper narrow, in contact with both preoculars ; 
lower wider, above the third labial; anterior above the second labial. 
Supraciliaries narrow, separated by twelve series of scales. Infralabials 
thirteen, first large. Submentals one pair, truncate in front, narrowly 
rounded behind. Seales in 36 rows, ten on each side of the median line 
with a central tubercle. Ventrals 200. Subcaudals 32 pairs, plus 17 
transverse series of small ones under the extremity of the tail, terminal 
spine well developed. 
Brown, with twenty-three reddish-brown rhombs on the median rows; 
the lateral angles are dark spots on the flank, sometimes isolated. On the 
middle of the body the rhombs have pale centers, posteriorly they are 
darker, irregular, confluent into a zigzag band. Tail dark brown, with 
narrow light cross-bands. Lower surfaces greenish-yellow, except the 
throat and chin, which are white (in spirits). A black band from the eye 
above the labials, broken upon the neck into a series of spots. Top of 
head uniform brown. Total length 0", 495; tail 0", 50. (Cope.) Sipurio. 
TRIGONOCEPHALUS, 
Oppel, 1811. 
Elongate fusiform, back slightly compressed; head large, distinet from 
the neck, depressed, triangular, broad behind, pointed in front; muzzle 
prominent, angular; tail short, tapering to a point. Crown-shields small, 
scale-like. Eye moderate, pupil vertical. Scales keeled. Anal entire. 
Subcaudals two-rowed, rarely simple. Mexico to Patagonia. 
