I I . XENODON. 



5. Xenodon severus. 



149 



Coluber severus, Linn. Mus. Ad. Frid. p. 25, pi. viii. fig. 1 (1754), 



and S. N. i. p. 379 (1766). 

 Cerastes severus, Law. Syn. Sept. p. 81 (1768). 

 Coluber breviceps, Shaw, Zool. iii. p. 430 (1802). 



versicolor, Merr. Tent. p. 95 (1820). 



saurocephalus, Wied, Beitr. Nat. Bras. i. p. 359 (1825). 



Xenodon severus, ScMeg. Phys. Serp. ii. p. 83, pi. iii. figs. 1-5 (1837) ; 



Dum. 8r Bibr. vii. p. 756 (1854) ; Giinth. Cat. p. 54 (1858). 

 severus, part., Jan, Arch. Zool. Anat. Phys:vi.. 1863, p. 317, and 



Icon. Gen. 19, pi. iii. fig. B (1866). 



Maxillary teeth 10-12 + 2. Head short, much, depressed; body- 

 more or less depressed. Eostral twice as broad as deep, the portion 

 visible from above measuring one fourth to one third its distance 

 from the frontal ; internasals nearly as long as broad, as long as the 

 prsefrontals or a little longer ; frontal as long as broad or slightly 

 longer, as long as or a little shorter than its distance from the 

 rostral, shorter than the parietals ; loreal deeper than long ; one 

 prae- and two or three (rarely four) postoculars ; temporals 1 + 2 or 

 1 + 3 ; eight upper labials, fourth and fifth entering the eye ; five 

 or six lower labiEils in contact with the anterior chin-shields, which 

 are larger than the posterior. Scales in 21 rows. Ventrals not 

 angulate laterally, 128-149 ; anal divided ; subcaudals 33-42. 

 Young with angular, brown, dark-edged bands separated by 

 narrow pale brown interspaces ; usually a round white spot on the 

 nape, and light and dark curved bands on the head ; beUy brown or 

 black, with large yellowish spots on the sides. These markings 

 usually become indistinct or disappear in the adult, some of which 

 are pale brownish or greyish above and yellowish inferiorly ; others 

 have broad black bands across the body, or black edges to some or 

 all of the scales, or the upper parts may be entirely black with a few 

 small yellowish spots. 



Total length 1500 millim. ; tail 190. 



Tropical South America. 



a. Yg. (V. 149 ; C. 36). Kosario de Cucuta, Mr. C. Webber [0.]. 



Colombia. 

 b S (V. 135 ; C. 36). Venezuela. Mr. Dyson [C.]. 



c, d. $ (V. 140, 139 ; C. 38, Demerara. 



e f. d (V 131 ; C. 40) & Berbice. Lady Essex [P.]. 



9 (V. 140; C. 37). 



a Yg. (V. 134; C. 41). Berbice. 



h 9 (V 140; C. 36). British Guiana. 



».' Yg. (V. 136; C. 38). Surinam. r, n x. u rr.n 



k I nsT 2 (V. 139; Para. R. Graham, Esq. [P.]. 



'c:37)&yg. (V. 142; 

 C. 40). 



„,,n. c? (V. 134; C. 36) Para. 



t ''I' ^0^ ^13^ ^b^% Moyobamba, N.B. Mr. A. H. Roft [C.]. 

 ' &'hgr. (V. 131 ; C. 36). Peru. 



