54 BULLETIN 32, UNITED STATES NATIONAL MUSEUM. 



II, Piiliitiuo teetli present. 



ex. Dentitiou isidout or syucrauterian. 

 j8. Aual plato divided. ■ 



y. Augular bono enclosed by the dentary. 

 E. Teeth equal. 



Two scale-pits ; scales smooth ; rostral not produced Proterodon Hallow. 



One scale- pit ; rostral not produced Diadophis B. & G. 



No scale-pits ; rostral not produced Ehadinwa^ Cope. 



Rostral large ; produced, with acute edge in front ; two nasals ; loreal present, 



ScapliiopMs Pet. 

 EE. Teeth longer posteriorly. 



Tail short ; rostral produced Simofes D. & B. 



Tail short ; rostral not jirominent ; one scale-pit Coronella'^ Laur. 



Tail very long ; rostral not prominent PUocerciis'^ Cope. 



77. Dentary bone attached loosely to the apex of the augular. 



Teeth equal ; no scale-pits Henicognalli its D. & B. 



(i^B. Anal plate undivided. 



Rostral plate produced both anteriorly and posteriorly HoIarcJnis^ Cope. 



No scale-pits ; rostral plate not produced Megahlahes Gthr. 



Two scale-pits Oplnholus" B. & G. 



aa. Dentition Diacranterian. 



(i. Rostral plate normal. 



y. Anal plate entire. 



Eye bounded by scales below ; lores plane Cyclagras^' Cope. 



Eye resting on labial plates; lores plane Xenodon'' Boie. 



Eye on labials ; lores grooA^ed ; two scale-pits Telcolepis Cope. 



//. Aual ])late divided. >* 



d. Scale-pits present (one). • 



Head very distinct ; robust Xenodon Boie. 



Head little distinct ; slender Liophis Wagl. 



dd. No scale-pits. 

 E. Rostral plate normal. 



Tail short ; pupil erect ; lores flat Hypsujlciia? Cope. 



Tail short ; pupil round ; body robust Opluomorphus Cop(!. 



Tail short ; pnpil round ; body slender AporopMs Cope. 



Tail very long ; pupil round ; slender Diomicus Bibr. 



EE. Rostral plate produced backwards and laterally, not forwards. 



Anal divided ; loreal present Lytorliynchus^o Pet. 



/?/?. Rostral trihedral and produced. 



Anal divided ; scales keeled Heierodon Beau v. 



Anal divided; scales smooth Lystrophis^'^ Cope. 



Anal entire ; scales smooth Lioheterodon Dum. 



^ Ablabes Gunth. not J). Sz.'B. Enicognathvs Jan. sm aSeit Styporhynchus Fot.'? 



' Mizodon Fisch. 



* Elavochrus Pet. C'ostniosophis Jan. 



■•Gen. nov., embracing all species witli entire anal plato hitherto referred to Simotea. 



^Latn2)ropeUis Fitz., Cope; Bellophis Tiockingt. 



^ LejoKophis Jan. 



^ Xenodon sugpectus Co-pe ; X. cohihrinus G-thr. ; X.angitstirontris Pet.; and X.hiprceocidaris Cope; 

 anil double or single in X. rhahdocepUalus "Wied. 



* Pseudoxyrrho2nis GvcaiXw. {? Homalocephalus Jau), is probably idiinli<'al with one of the genera of 

 sect. 7Y, but the character of the scale-pits is unknown. 



^ Psrudodipsas Pet. ; Gomastcs Jan. 



'" Gatachlem>7an; Ophirhina Hooago. 



"Typo Heierodon dorhignyi quid Ilhniaspis Schl.? 



