208 THE CLASSIFICATION OP THE OPHIDIA. 



II. Calyculate and not capitate. (Calyculati.) 

 f. Hemipenis divided. 



Rostral recurved Rhinostoma 



Rostral normal ; pupil erect Oxyrrhopus Wagl. 



Rostral normal ; pupil round PMlodryas Wagl. 



(pip. Hemipenis undivided. 

 Rostral normal Thamnodynastes Wagl. 



III. Capitate (also calyculate). (Capita ti.) 



Hemipenis undivided ; colubriform Coniophanes Hallow. 



Hemipenis undivided ; fusiform Hydroealamus Cope. 



IV. Spinous to apex (divided). (Spinosi.) 



Two nasal plates TacJiymenis Wiegm. 



One nasal plate Tomodon D. & B. 



V. Bands of spines extending to apex. (Calycispinosi.) 



Spines of bands minute ; caudal scuta one-rowed Scytale Wagl. 



The groups into which this subfamily is divided correspond closely with those 

 which are found in the subfamily Dromicinse. The group VI, including only the 

 genus Heterodon, is the only one of the latter which is not represented in the former. 

 Apart from penial characters, the genera of the corresponding groups sometimes 

 resemble each other, but frequently they do not. Thus Alsophis resembles Philodryas, 

 and Rhadinaea resembles Coniophanes, and Acanthophallus resembles Tomodon in 

 general characters. 



dipsadin^:. 



I. Apex flounced. (Flabellati.) 

 a. Fusiform. 



Internasals distinct ; flounces spinous ; subcaudals one-rowed Lrieclds Pet. 



Internasals distinct ; flounces spinous ; subcaudals two-rowed Urobelus Rhdt. 



Internasals and nasals fused ; flounces not spinous ; subcaudals two-rowed Stenorhina D. & B. 



aa. Attenuate. 

 Calyces large, irregular ; gastrosteges angulate Ohrysopelea Boie. 



II. Calyculate, not capitate. (Calyculati.) 



a. Dipsadiform (head short, very distinct from neck). 



/5. No spines on hemipenis. 

 Calyces numerous * Dipsadomorphus Gthr. 



/?/? Spines present. 



Calyces numerous Dipsas Laur. 



Calyces very few Crotaphopeltis Fitz. 



aa. Attenuate. 



ft. No diverticulum. 



Pupil horizontal Cladophis Dum. 



Pupil round Oxybelis Wagl. 



/5/?. Hemipenis with a diverticulum. 

 Pupil round Dryophis. 



* Liophallus Cope, Proceeds. Acad. Phila., 1894, p. 437. 



