522 



TIPEKID^. 



Trigonocephalus bilineatus, Bocourt, Miss. Sc. Mex., Kept. pi. xxvii. 

 fig. 1 (1882). 



Snout obtusely pointed, not turned up, flat above, with sharp 

 eanthus. Eostral as deep as broad or slightly broader than deep ; 

 a pair of internasals and a pair of priefrontals ; frontal shorter than 

 its distance from the end of the snout, as long as or shorter than 

 the parietals ; upper prseooular 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 

 sfrongly 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 

 cross-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 

 eanthus, 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. $ (Sc. 23 ; V. 141 ; Pacific Coast of ' O. Salvin, Esq. [C.]. 

 0. 52). Guatemala. (Type.) 



b. d (So. 23 ; V. 135 ; 0. 61). Belize. P. L. Sclater, Esq. 



[P.]. 



c. $ (Sc. 25 ; V. 140 ; 0. 54). Yucatan. 



d. e. Hgr. (Sc. 23, 23 ; V. 187, Presidio, nr. Hr. A. Forrer [C.l. 

 ■ 187 ; C. 64, 62). Mazatlan. 



f-ff. d (Sc. 23; V. 141; Tres Marias Ids., Hr. A. Forrer [0.]. 

 0. 59) & yg. (Sc. 24; W.Mexico. 



V. 137 ; 0. 55). 



3. Ancistrodon contortrix. 



Boa contortrix, Linn. S. N. i. p. 873 (1766). 



Agkistrodon mokasen, Pal. de Beauv. Tr. Amer. Philos. Soc. iv. 



1799, p. 370. 

 Scytale contortrix, Latr. Sept. iii. p. 159 (1802). 

 Cenchris mokeson, Duud. Rept. v. p. 358, pi. Ix. figs. 3 & 4 (1802) ; 



Rarl. Med. Phys. Bes. p. 128 (1835). 

 Soytalus cupreus, Bafin. Amer. Jcmrn. Sc. i. 1819, p. 84 ; JIarl. I. c. 



p. 130. 

 Scytale mokeson. Say, Amer. Journ. So. i. 1819, p. 257. 

 Cenchris marmorata, Bote, Isis, 1827, p. 662. 

 P Acontias atrofuscus, Troost, Ann. Lye. N. Y. iii. 1836, p. 181. 

 Trigonocephalus cenchris, part., Schley. Phys. Serp. ii. p. 653, pi. xx. 



figs. 10 & 11 (1837). 

 contortrix, Holbr. N. Am. Herp. ii. p. 69, pi. xiv. (1838), and 



2ud ed. iii. p. 39, pi. viii. (1842) y De Kay, N. Y. Faun. iii. Rept. 



