30 NORTH AMERICAN BATRAOHIA AND REPTILlA. 



]j. Anteorbitals present. 



fSuperciliaries small, narrow, width nearly uniform;- 



eye small 7. Contia. 



:}:Snperciliaries quite large, broadest posteriorly; eye 



large 13. Cyclophis. 



h. Nasals two. 



1. Loral absent 4. Tantilla. 



2. Loral present. 



X. Anteorbitals present. 

 fOne anteorbital. 



■'^Dorsal rows 17 12. Dromicus. 



**Dorsal rows 25 to 29 14. Coluber. 



:}:Two anteorbitals. 



■^liead depressed; anteorbitals nearly equal in 



size 11. Diadophis. 



**Head deep; upper anteorbital much the largest, 



17. Bascaniuin. 

 y. Anteorbitals absent 2. Virginia. 



B. Dorsal scales smooth ; anal entire. 



a. Loral absent .9. Osceola. 



h. Loral present. 



1. Rostral acute, produced forwards, causing a sharply 

 pointed snout 8. Ce7noj)hora. 



2. Rostral not produced. 



X. Superciliaries moderate; scales scarcely overlapping; 



head depressed 10. Ojyhiholus. 



y. Superciliaries broad ; scales imbricate'; head deep. 



15. Spilotes. 



C. All or part of dorsal scales carinate; anal entire. 



a. Postfrontals two pairs 16. Pityophis. 



h. Postfrontals one pair 18. Eutmnia. 



D. All or part of dorsal scales carinate; anal divided. 

 a. Nasals two. 



1. Rostral produced, recurved and keeled . 23. ^e^e7'(9^6>?^. 



2. Rostral not produced. 



X. One prefrontal 3, Haldea. 



y. Two prefrontals. 

 fLoral present. 



*Scales on back slightly carinate; sides smooth; 



G. 200-235 14. Coluber. 



*"A11 dorsal scales carinate ; G. 130-170. 



21. Tropidonotus. 

 :{;Loral absent 19. Storeria. 



