SNAKES. 23 



Synopsis of the Genera. 



1. SiMOTES. Rostral conical, protruding, extending backwards 



between the anterior frontals. Scales in seventeen or nine- 

 teen rows. East Indies ; North America ; Algiers. 



2. Ablabes. Rostral moderate. All teeth equal. All scales 



smooth. United States ; Africa; Asia. 



3. Trachischium. Scales of the ischiadic region provided 



with granulated keels. Sikkim. 



4. PsAMMOPHYLAX. Rostral rounded, not protruding, with 



a long posterior process. South Africa. 



5. Tachymenis. Either two anterior oculars and a separate 



loreal, or loreal united with lower ocular. Posterior max- 

 illary tooth grooved. South Europe ; Chili. 



6. Coronella. Rostral moderate ; one anterior ocular. Pos- 



terior maxillary tooth either smooth, longer, and in a con- 

 tinuous row with the anterior ones, or grooved. Almost 

 every part of the globe. 



7. LioPHis. Rostral moderate; posterior maxillary tooth 



longest, smooth, and separated from the anterior ones by 

 an interspace. Warmer parts of America. 



8. Erythrolamprus. Body encircled by black rings. Pos- 



terior maxillary tooth grooved. South America. 



9. Hypsirhynchus. Forehead concave ; muzzle pointed and 



raised. Barbadoes. 



1. Si motes, Dum. ^ Bibr. 



Head short, conical, not distinct from neck ; rostral shield 

 as in Oligodon, rather flat in front, pointed behind, and far 

 produced backwards between the anterior frontals ; two nasals, 

 nostril between ; one anterior ocular (in one species three), two 

 posterior oculars. Scales smooth, in seventeen or nineteen rows 

 (Dumeril's S. trinotatus twenty-one ?). Posterior maxillary 

 teeth longest, smooth. Crown of head with regular, generally 

 arrow-shaped marks. East Indies. (North America; Algiers.) 



Simotes, Dum. Sf Bibr. vii. p. 624. Heterodon, sp., Dum. Sf 

 Bibr. vii. p. 778. Coronella, sp., Schleg. Ess. ii. p. 77, 79, and 

 Heterodon, sp., id. p. 102, and Xenodon, sp., id. p. 90. Rhino- 

 stoma, sp., Holbrook, N, Amer. Herpet. iii. p. 125 ; Baird, 

 Girard Catal. p. 118. Coronella, sp., Boie, Isis, 1827, p- 539. 

 Elaps, sp.. Coluber, sp., auct. prior. 



