10, TROPIDOXOTUS, 201 



I. Tropidonoxus. — Maxillary teeth not more than 30, the hinder 

 gradually enlarged (see fig. 11, p. 170). Eyes and nostrils 

 lateral; iuternasal shields broadly truncate anteriorlj'. 



1. Tropidonotus leptocephalus. 



Eutainia leptoeephala, Baird (§• Gir. Cat. N. A^n. liept. p. 29 

 (1853) ; Oil: U.S. Rrplor. Expecl, Jlerp. p. 151, pi. xiii. tigs. 7- 

 13 (1858); Cooper, Rep. U.S. Krplor. Surv. li. It. xii. pt. ii. 

 p. 297 (1860) ; Cope, in Wheeler's Rep. U.S. Surv. IF. lOOth 

 Mer. V. p. 550 (1875), and Proc. Ac. Philad. 1883, p. 23, and 

 Proc. U.S. Nat. Mus. xiv. 1892, p. G60. 



Tropidonotus ordiuatus, part., G'nnth. Cat. p. 73 (1858). 



Eutaiuia cooperi, Kennicott, Rep. U.S. Kvplor. Surv. R. R. xii. 

 pt. ii. p. 296, ])1. XV. fig. 1 (1860) ; Cope, Wheeler s Rep>. p. 551. 



atrata, Kennicott, I. c. p. 296 ; Cope, I. c. 



Tropidonotus cooperi, Jan, Arch. Zool. Anat. Rhys. ii. 1865, p. 212. 



sirtalis, var. leptoeephala, Jan, Icon. Gen. 35, pi. iv, tig. 2 



(1867) ; Gar7Ji. N. Am. Rept. p. 139 (1883). 



sirtalis, var. infernalis, part., Gann. I. c. p. 24. 



Eye rather small, considerably smaller than in T. ordinatns; head 

 rather elongate, but slightly distinct from neck, llostral broader 

 than deep, visible from above ; internasals as long as broad or 

 broader, a little shorter than the praefrontals ; frontal once and a 

 half to once and two thirds as long as broad, as long as its distance 

 from the end of the snout, shorter than the parietals ; loreal 

 usually longer than deep ; two (rarely one) pra)- and three post- 

 ocuLirs ; temporals 1 + 2; seven (rarely six or eight) upper labials, 

 third and fourth entering the eye ; four lower labials in contact 

 Avith the anterior chin-shields, which are shorter than the posterior. 

 Scales in 17 (rarely 19) rows, sti'ongly keeled, outer row smooth or 

 feebly keeled. Yentrals 139-152 ; anal entire ; subcaudals 54- 

 70. Olive or brown above, with small black spots, with or without 

 three more or less distinct light longitudinal streaks, the median 

 yellow or orange, the laterals greenish yellow ; upper lip yellowish; 

 usually a black streak behind the eye, and sometimes a black blotch 

 on each side of the occiput ; usually a pair of yellow dots close 

 together on the suture between the parietal shields ; lower parts 

 olive or plumbeous grey, with or without black dots. 



Total length 600 millim. ; tail 140. 



North America west of the llocky Mountains, from British 

 Columbia to North California. 



A. Scales in 17 rows; light dorsal stripes distinct. 



a-h. c? (V. 145, 149, 147, 148 ; Sumass Prairies, Boundary Commis- 



(;. 66, 60, 62, 64), $ (V. 139 ; Brit. Columbia. sion [C.]. 



C. 60), hgr. (V. 146; C. 54), 



& yg. (V. 146, 141 ; C. 56, 



60). 

 i-ni. c? (V. 149, 147 ; C. 6-3, Vancouver Id. H.M.S. ' Plumper.' 



68), 2 (V. 150; C. 56), & 



yg. (V. 139; C. 58). 



