THE CLASSIFICATION OP THE OPHIDIA. 201 



XENODONTIN^E. 



After the subtraction of the Dromi'cinse, a limited number of genera are referable 

 here. They are all Neotropical. 



<p. Rostral plate not recurved. 



Hemipenis undivided ; no scale-pits Aporophia Cope. 



Hemipenis divided ; no scale-pits Opheomorplius Cope. 



Hemipenis divided ; one scale-pit * Xenodon Boie. 



<p<p. Rostral plate recurved. 

 Hemipenis divided ; one scale-pit Lystrophis Cope. 



DROMICIN.^. 



A. No proximal diverticulum of the left lung. 



I. Hemipenis transversely plicated (divided) ; (Flabelluti). 



Plica: not papillose ; diacranterian ; colubriform Eelicops Wagl. 



Plica; not papillose ; isodont ; fusiform Pseudoeryx Fitz. 



Plies papillose ; isodont ; fusiform Rhabdosoma D. & B. 



II. Calyculate and not capitate (Calyculati). 

 <p. Hemipenis undivided. 



Fusiform ; isodont , ■ ■ • ■ Oarphophiops Gerv. 



Colubriform; isodont; two nasals Eiadoplris B. & G. 



Colubriform ; diacranterian ; one nasal. Amastridium Cope. 



Colubriform ; diacranterian ; two nasals ' Hyp&irhynchus Gthr. 



<p<p. Hemipenis double. 



Fusiform ; isodont Farancia Gray. 



Colubriform ; diacranterian ; no scale-pits Dromicm Bibr. 



Colubriform ; diacranterian ; one scale-pit. iMonobothru Cope. 



Colubriform ; diacranterian ; two scale-pits Halsophis Uope. 



III. Capitate (or pocketed at base of calyculate portion) (Capitati). 

 <f<p. Hemipenis undivided. 



Scale-pits single ; scales smooth Plioeercus Cope. 



No scale-pits ; scales smooth Rhadinaa Cope. 



Scales keeled ; prenasals in contact Tretanorhinus D. & B. 



<p<p. Hemipenis divided. 

 Rostral normal ; isodont Ninia B. & G. 



IV. Calyculate with spinous bands to apex (Calycispinosi). 



Hemipenis bifurcate ; spines not ossified to apex ; diacranterian ; colubriform % Tamiophallus Cope. 



Hemipenis bifurcate ; subisodont ; attenuate Uromacer D. & B. 



V. Exclusively spinous to apex ; (diacranterian) (Spinosi). 



Anterior teeth wanting Enulius Cope. 



Anterior teeth present ; internasals fused ; fusiform § Hydrops Wagl. 



Anterior teeth present ; anal divided ; no scale-pits ; colubriform ; not bifurcate. . .|| Echinanthera Cope. 



Anterior teeth present ; anal entire ; one scale-pit ; colubriform ; bifurcate Aeanthophallus Cope. ■ 



AA. Left lung with a proximal diverticulum extending to the throat. 



VI. Calyculate and capitate. 



Rostral recurved ; hemipenis divided ; diacranterian . .■ Eeterodon Beau v. 



* Includes Liophis Wagl. t T yP e Eromicus chamissonis Auct. 



X Type Lygophis nicagus Cope. Pockets separate the spinous bands from the calyces. 



§ H. martii Wagl. examined. II Type Aporophis cyanopleurus Cope. 



