CROCODILIANS, LIZARDS, AND SNAKES. 779 



yy. Calyces numerous, or when few replaced by spines. 



5. Calyces mingled with large pockets. x- b^:„ 



■^ ,,x Dendrophi8 Boie. 



Isodont; attenuate 



5(5. Calyces without large pockets. 



E. Rostral normal or compressed; pupil round. 

 Z. Anterior teeth not larger than jtosterior. 

 ?;. Two median rows of scales. 



Coiubriform; isodont Herpetodryas ^ Boie. 



v7]. One median row of scales. 

 ' 6 Trachea enormously expanded transversely. 



Subisodont; attenuate Tftra«Oi>s Hallowell. 



00. Trachea normal. 



i. Calyces numerous; fringed, 

 fc. One nasal plate. 

 Isodont; colubriform; anal divided . ..Ci/cioi)fii8 C4unthpr. 

 Isodont; coronelliform ; anal divided. 



Contia Baird and Girard. 

 Afc. Two nasal plates. 



Anal divided; no epiglottis ; attenuate; a loreal. 



Leptophis Bell. 



As Leptophis, but no loreal Hapsidophryn Fischer. 



Anal divided; no epiglottis ; colubriform; a loreal. 



Coluber Linnii'us. 



As Coluher, but anal entire Spilotes Wagler. 



As Spilotes, but an epiglottis Epiglottophis Cope. 



As Spilotes, but rostral prominent and compressed. 



Bhinechis Wagler. 



Anal entire ; plates normal ; coronelliform. 



Osceola Baird and Girard. 

 Anal entire; rostral prominent, produced backwards; 



four prefrontals; an epiglottis Fityophis Holbrook. 



i L Calyces numerous ; not fringed. 



Attenuate, dipsadiform ; isodont Bucephalus A. Smith. 



Coronelliform ; anal divided ; one scale-pit. 



Coronella Laureuti. 



Coronelliform; anal divided; two scale-pits. 



Proterodon Hallowell, 



Colubriform; anal divided; internasal and nasal united. 



SymphiviKS Cope. 

 Hi. Calyces few; apical. 



Subisodont; coronelliform; two nasals; a loreal; anal 



gQ^ij.^ Ophibolus Baird and Girard. 



Isodont; fusiform; one nasal; no loreal; anal entire. 



Stylosoma Brown. 

 ZZ- Anterior teeth longer than posterior. 



Coronelliform; pupil erect; calyces not fringed. 



Dinodon Dum^ril and lUbron. 



£ £. Rostral plate produced or recurved. 

 Z. Rostral not free laterally; pupil round. 

 77. Subcaudals one-rowed. 



Internasals distinct; calyces fe^^ . Bhinochilus Baird and Girard. 

 j/rj. Subcaudals two-rowed. 



0. Internasals fused with nasals. 



Fusiform; isodont; rostral depressed; calyces fringed. 



Chilomenisous Cope. 



^Zaocys Cope is apparently allied to this genus, but 1 do not know the penial 

 structure. 



