:>42 PROCEEDINGS OF THE ACADEMY OF 



The number of rows of scales will distinguish this species from Tropidono- 

 tus Woodhousei Hallow. Tropidonotus C o u c h i i Cope (Nerodia Couchii 

 Kennicott, Proc. Phila. Acad., Aug., 1860), has a very differently formed head, 

 but one preocular shield, and a few other distinguishing peculiarities. Tro- 

 pidonotus v a lid u s Cope (Regina valida Kenn. 1. c.) possesses a short head, 

 a rostral plate as high as broad, one preocular, and small occipitals, according 

 to Mr. Kennicott, none of which peculiarities exist in the T. tephropleura. 



The three Tropidonotes here described possess the true syncranterian type 

 of dentition. So also, does the Trop. rig i d u s Holbr., but the T. leberis 

 Holbr., and some other species included by Baird & Girard in their genus 

 " Regina," exhibit an almost constant isodont dentition. It is possible that 

 a genus intermediate between Tropidonotus and some forms of Homalopsina?, 

 may exist in nature ; that such genus be characterized by the possession of 

 teeth of equal lengths, and that the only name applicable to it be Regina : 

 yet the generic separation of the r i g i d u s from the leberis will not accord 

 with the present views of most herpetologists. 



Hekpetodryas Boie. 



H. Boddaertii Schleg. 



A variety of this species has been obtained in the vicinity of Xalapa, Mexico, 

 by Sr. R. M. DeOca. It is distinguished by the color of the tail, which is of a 

 bright salmon tint. Mus. Smithsonian Inst. 



Spilotes Wagler. 



The species of this genus may be divided into two sections, one character- 

 ized by the possession of keeled scales, the other having them smooth. To 

 the former belong the S. pullatus, poecilostoma and poecilono- 

 tus; to the latter, which Fitzinger has called Drymarchon, the S. cora'is 

 andm elanurus pertain. All the structural peculiarities of this latter group 

 are shared by the Colubri C o u p e r i and obsoletus of Holbrook's American 

 Herpetology. The latter species is not the obsoletus of Say, as supposed 

 by Dr. Holbrook, which has been correctly identified by Mr. Kennicott, and 

 shown to belong to a different genus ; vid. Scotophis obsoletus Kenn. 

 Proc. Acad. Aug., 1860. We therefore propose that Holbrook's species in 

 question be known henceforth as 



Spilotes Couperi Cope. 



Syn. Coluber Couperi Holbrook, N. Am. Herp. iii. 75, pi. xvi. 

 Georgia Couperi Baird & Girard, Catalogue, p. 92. 



Spilotes erebennus Cope. 



Syn. Coluber obsoletus Holbr. 1. c. iii. p. 61, pi. xii. 



Georgia obsoleta Bd. & Grd. 1. c. p. 158. U. S. and Mex. Bound. 

 Surv. Rept. pi. xv. 



Pityophis Holbrook. 



P. hjematois Cope. 



Scales in from thirty-one to thirty -five rows, the exterior ten or twelve en- 

 tirely smooth, the central faintly carinate ; the scales three times as wide as 

 long near the middle of the body. Head distinct, elongate, depressed, espe- 

 cially upon the region of the sutura coronalis. Occipital shield as long as the 

 vertical, but subject, as in other species of the genus, to subdivision. Length 

 of the vertical one and a half times the anterior breadth, the superciliary 

 borders concave and slightly divergent posteriorly. Posterior angle obtuse, 

 Postfrontals four, elongate, all bordering the vertical. Rostral not prominent ; 

 as broad as high, possessing six sutural borders, the nasal twice as long as any 

 of the others. Nasal shields large, loreal longer than high. Preoculars nor- 

 mally two, sometimes three, or one. Postoculars three, exceptionally four. 



[Aug. 



