1886.] 4b7 [Cope. 



Maxillary more robust ; scales smooth ; a frenoorbital plate 



Rhabdosoma* D. & B. 

 Maxillary more robust ; scales keeled ; a frenoorbital plate 



Elapoides\ Boie. 

 TjrjTjrj. Two nasal and two anal scuta. 



A loreal ; no preocular ; two pairs geneials Virginia B. & G. 



A loreal ; no preocular ; one pair geneials Adelphicus% Jan. 



A loreal and a preocular ; two pairs geneials Sonora B. & G. 



No loreal ; a preocular ; jaws weak Brachyorrhos Kuhl. 



ee. Palatine bones without teeth. 



Two anals and nasals ; a loreal and a preocular Oligodon Boie. 



Two anals and nasals ; a loreal and no preocular Colobognat7ms Pet. 



ff. Nasal scutum minute. 



No internasals; preoculars present Calamaria Boie. 



Two internasals ; a preocular , Pseudorhabdium Jan. 



Two internasals ; no preocular Oxycalamvs Cant. 



fff. No nasal scutum. 

 No loreal, nor pre- nor postocular TypMogeophis Giinth. 



COTtONELLIN.E. 



I. No palatine teeth. 



Anals two ; one internasal ; scales smooth Tripeltis% Cope. 



Anal plate divided ; two internasals; scales smooth Oligodon} Boie. 



II. Palatine teeth present. 



a. Dentition isodout or syncranterian. 

 j3. Anal plate divided. 

 y. Angular bone enclosed by the dentary. 

 e. Teeth equal. 



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



No scale-pits, rostral not produced Rhadincea^ Cope. 



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



presen t Scaphiophis Pet. 



es. Teeth longer posteriorly. 



Tail short ; rostral produced Simotes D. & B. 



Tail short ; rostral not prominent, ; one scale-pit Coronella** Laur. 



Tail very long ; rostral not prominent Pliocercus\\ Cope. 



yy. Dentary bone attached loosely to the apex of the angular. 



Teeth equal ; no scale-pits Henicognathus D. & B, 



/3/3. Anal plate undivided. 



* Rhabdium, D. & B. 



t Geophis Wagl. Catastoma Wagl 



% Rhabdosoma Boc. not D. & B. Rhpgnops Cope. 



gGen. nov. type Oligodon brevicauda Gthr. 



|| ? Rhynchocala mus Gthr. 



If Ablnbes Giinth. not D. & B. Enicognathus Jan. 



** Mizodon Fisch. 



tt Elapochrus Pet. Cosmiosophis Jan. 



