522 VIPERID ®. 
ap pep ety bilineatus, Bocourt, Miss. Sc. Mex., Rept. pl. xxvii. 
fig. 1 (1882). 
Snout obtusely pointed, not turned up, flat above, with sharp 
eanthus. Rostral,as deep as broad or slightly broader than deep ; 
a pair of internasals and a pair of prefrontals ; frontal shorter than 
its distance from the end of the snout, as long as or shorter than 
the parietals; upper preocular separated from the posterior nasal 
by a loreal; two postoculars and one or two suboculars, separating 
the eye from the labials; 8 or 9 (rarely 7) upper labials, second 
forming the anterior border of the loreal pit. Scales more or less 
strongly keeled, in 23 (rarely 25) rows. Ventrals 135-141; anal 
entire; subcaudals 52-64, anterior single, posterior divided, the 
divided shields usually more numerous than the single. Yellowish 
or reddish to dark brown above, with more or less distinct darker 
eross-bands or alternating transverse blotches with interrupted 
yellow edges; a vertical yellow, black-edged line on the rostral and 
symphysial shields, a fine yellow line round the snout on the 
canthus, continued behind the eye to the neck, and a broader 
yellow, black-edged streak on the upper lip from the anterior nasal 
to the last labial ; brownish to blackish beneath, with white, black- 
edged markings. 
Total length 1100 millim.; tail 200. 
Mexico, Guatemala, Honduras. 
a. Hgr. 2 (Se.28; V. 141; Pacific Coast of 0. Salvin, Esq. [C.]. 
O, 52). Guatemala. (Type.) 
b. ¢ (Sc. 23; V.135;C. 61). Belize. Pr * Sclater, Esq. . 
P.). 
c. Q (Se. 25; V. 140; 0.54). Yucatan. 
d, e. Hgr. (Sc. 23, 23; V.137, Presidio, nr. Hr. A. Forrer [C.]. 
137 ; C. 64, 62). Mazatlan. 
f-g. 3 (Se. 28; V. 141; TresMariasIds., Hr. A. Forrer[C.]. 
©. 59) & yg. (Sc. 24; W. Mexico. 
V. 187; C. 85). 
3. Ancistrodon contortrix. 
Boa contortrix, Linn, S. N. i. p. 373 (1766). 
Agkistrodon mokasen, Pal. Beauv. Tr. Amer. Philos. Soc. iv. 
1799, p. 370. 
Seytale contortrix, Latr. Rept. iii. p. 159 (1802). 
Cenchris mokeson, Daud. Rept. v. p. 358, pl. lx. figs. 8 & 4 (1802) ; 
Harl. Med. Phys. Res. p. 128 (1835). 
Seytalus cupreus, Rajfin. Amer. Journ. Se. i. 1819, p. 84; Harl, 1. ¢. 
30 
. 130, 
Seytale mokeson, Say, Amer. Journ. Se. i. 1819, p. 257. 
Cenchris marmorata, Bote, Isis, 1827, p. 562. 
P Acontias atrofuscus, Troost, Ann. Lye. N. ¥. iii. 1836, p. 181. 
Trigonocephalus cenchris, part., Schleg. Phys. Serp. ii. p. 558, pl. xx, 
figs. 10 & 11 (1837). 
—— contortrix, Holbr. N. Am. Herp. ii. p. 69, pl. xiv. (1888), and 
2ud ed, iii. p, 89, pl. viii, (1842); De Kay, N. Y. Faun. iii. Rept. 
