COLUBRID^. — ex. 189 



dd. Nasal plates 2, the nostril between them; a loral plate; no preocu- 



lar; (scales 15 or 17, V. P. 115 to 125). . . . VlEGiKIA, 271. 



cc. Prefrontal single; no pveocular; nasal single; (scales 19; V.P.170to 



205) Faeancia, 272. 



aa. Head more or less distinct from the body which is not specially rigid 



{Coronellimx,' ColubriTUz, HomalopsincB). 

 f. Rostral plate normal, not recurved nor keeled. 

 g. Anal plate divided ; head not very short, 

 A. Dorsal scales keeled more or less. 

 i. Nasal plates 2, the nostril between them. 

 _/. Prefrontals 2. 



ifc. Loral plate present. 



I. Scales on back and sides all keeled (ventral plates 130 to 170). 

 m. Posterior teeth not longer (scales 19 to 21). . Eegina, 277. 

 mm. Posterior teeth longer (scales 23 to 31). 



Natkix, 278. 



II. Scales on sides not keeled; those on back often with the 



keels obscure (V. P. 200 to 270; scales 25 to 29). 



Callopeltis, 279. 

 Wc. Loral plate absent (scales 15 to 17; V. P. 125 to 130). 



Storeria, 274. 

 jy. Prefrontal single ; nasals 2 ; loral present ; no preocular (scales 17 ; 

 V. P. 120 to 130) ; body slender, the head distinct. 



Haldea, 273. 

 M. Nasal single, pierced by the nostril ; loral plate present. 



n. Nasal plate grooved; tail short (scales 19; V. P. 130 to 



140) Clonophis, 275. 



nn. Nasal plate not grooved below nostril ; tail very long, 

 about J of length (scales 17; V. P. 150 to 360). 



Ophbodeys, 280. 

 M. Dorsal scales not keeled. 



V. Nasal single, pierced by the nostril; loral present; tail 

 long (scales 15 ; V. P. 125 to 140). Liopeltis, 281. 

 00. Nasal plates 2, the nostril between them; loral pres- 

 ent ; preocnlars 2. 

 p. Head depressed; preoculars nearly equal in size 

 (scales 15 to 17 ; V. P. 140 to 200 or more). 



DiADOPHis, 284. 



pp. Head not depressed; upper preocular much the 



larger ; lower sometimes wanting ; (scales 17 ; V. 



P. 170 to 210) Bascanion, 282. 



gg. Anal plate entire. 



J. Dorsal scales all or part of them keeled; head 

 rather long. 



1 These three sub-families are so vaguely bounded that I cannot use theb distinc- 

 tive characters in the key. Professor Cope gives the following deflnitions : — 



Homalopsinw. (Genera 273 to 278 ) " Hypapophyses spinous to caudal region; an- 

 terior teeth not enlarged; body not slender; head distinct." 



Coluirince. (Genera 279 to 283.) Head more distmct and elongate; body and tail 

 longer; teeth entire, not longer in front. 



Corondlinai. (Genera 284 to 288.) Head slightly distinct, short ; teeth entire, 

 not enlarged in front. 



