10. TBOPIDONOTUS. 243 



Nerodia erythrogaster, Baird 8f Oir. I. c. p. 40. 



agassizii, Baird ^ CHr. I. c, p. 41. 



woodhouaii, Baird Sf Oir, I. c. p. 42. 



holbrookii, Baird (§■ Oir. I. c. p. 43. 



niger, Baird Sr Oir. I. o. p. 147. 



rhombifer, Baird ^ Oir. I. c. p. 147. 



transversa, Baird 8f Oir. I. c. p. 148. 



Tropidonotus pogonias, Dum. ^ Bibr. vii. p. 574. 



obliquus, Sallow. Proa. Ac. Phzlad. 1856, p. 248 ; Oarm. Bull. 



Essex Inst. xxiv. 1892, p. 103. 



cyclopion, part,, Oiinth. Cat. p. 248. 



Nerodia coucMi, Kennicott, Proc. Ac. PMlad. 1860, p. 335. 

 Tropidonotus couchii. Cope, Proc. Ac. Philad. I860, p. 342. 



woodliousii. Cope, I. c. ; Jan, II. cc. p. 222, pi. iv. fig. 1. 



Msectus, Cope, Proc. U.S. Nat. Mus. x. 1887, p. 146. 



Natrix fasoiata, Cope, Proc. U.S. Nat. Mus. xi. 1888, p. 392, and 



xiv. 1892, p. 670. 



bisecta, Cope, Proc. U.S. Nat. Mus. xiv. 1892, p. 670, 



fasciata pleuralis, Cope, I. c. p. 672. 



rbombifera. Cope, I. c. p. 673. 



Eye rather small. Eostral broader than deep, visible from above ; 

 internasals much narrowed in front, as long as broad or a little 

 longer, as long as or shorter than the prsefrontals ; frontal once and 

 two thirds to twice as long as broad, as long as its distance from 

 the end of the snout, shorter than the parietals ; loreal as long as 

 deep or deeper ; one (rarely two) pree- and three (rarely two) post- 

 oeulars ; temporals 1 + 2 or 1 + 3 ; eight upper labials, fourth or 

 fourth and fifth entering the eye ; five (rarely four) lower labials in 

 contact with the anterior chin-shields, which are shorter than the 

 posterior. Scales in 23 to 27 rows, strongly keeled, of outer row 

 more or less distinctly keeled. Ventrals 128-154 j anal divided ; 

 subcaudals 58-82. 



Total length 1100 miUim : tail 240. 



North America east of the Eocky Mountains ; Central America. 



A. (Forma typica.) Brown above, with a dorsal row of large trans- 

 verse blackish spots and an alternating series of smaller spots 

 on each side, or with dark brown cross bands ; beUy spotted 

 with black or brown. Scales in 23 or 25 rows. 



a. r? (Sc. 23 ; V. 143 ; 0. 75). Canada. J. Cruickahanks, Esq. 



^ [0.]. 



h 2 fSc 23 ; V. 146 : C. 66). Canada. Officers of the Chatham 



Museum [P.]. 



c-d. Yg. (Sc. 25 ; V. 136, Bloomington, C. BoUman, Esq. [C.]. 



135 ; C. 76, 60). Indiana. 



e. Hgr. (Sc 25 ; V. 180; C. ?). Florida. Smithsonian Institution 



f-Q. Hm. (Sc. 23 ; V. 137 ; New Orleans. 



0.72) & yg. (Sc. 23; V. 



130 ' C 77") 

 hr4. Yg. (Sc. 25, 23 ; V. 149, New Orleans. M. Salli [C.]. 



149 ; 0. 75, 80). 



