BatracMans of the Province Rio Grande do 8ul. 429 



Miss. Sc. Mex., Rept. p. 407, pi. xxii. c. fig. 2 ; Bouleng. Aun. & Mag. 



Nat. Hist. (5) xvi. p. 87. 

 Euprepes (Mabuia) virqatus, Peters, Mon. Berl. Ac. 1874, p. 627. 

 ? Mabuia Joberti, Tliomin. Bull. Soc. Pliilom. (7) viii. 1884, p. 148. 

 Mahuia tetratcenia, Boettg. Zeitsclir. f. Naturw. Iviii. 1885, p. 227. 



B. M. : V. I. 



r H I D I A. 



Colubridae. 



I. A single shield between the nasal and the eye ; a 



pair of internasals ; eye small, with round pupil ; 

 tail very short. 



a. No grooved fangs ; a pair of preefrontals, in contact 



with the eye ; anal single Geophis. 



b. Grooved fangs present ; a single prsefrontal, sepa- 



rated from the eye by a prjeocular ; anal divided. Elapomorphus. 



II. Loreal and prseocular shields present * ; a pair of 



internasals ; pupil round. 



A. No grooved fangs ; maxillary teeth equal or 



siibequal. 



a. Nostril pierced in a single nasal ; tail not one fourth 



of the total length Ablabes. 



b. Nostril between two nasals ; tail not one third of 



the total length ; scales smooth ; eye moderate . . Curonella. 



c. Nostril between two nasals ; tail not one third of 



the total length ; scales smooth ; eye large Fti/as. 



d. Nostril between two nasals ; tail not one third of 



the total length ; scales keeled ; side of belly an- 

 gular Spilotes. 



e. Nostril between two nasals ; tail more than one third 



of the total length Herpetodryas. 



B. No grooved fangs ; posterior maxillary teeth 



much enlarged and separated from the others 

 by an interval. 



a. Tail not more than one fourth of the total length ; 



snout and scales normal Liophts. 



b. Tail more than one fourth of the total length Dromicus. 



c. Tail short ; dorso-lateral scales narrow, diagonal . . Xenodon. 



d. Tail short ; snout pointed, turned up ; rostral shield 



keeled above Heterodon. 



C. Grooved fangs present. 



a. Grooved fangs moderate, not more than twice as 



long as the solid ones Philodri/as. 



b. Grooved fangs very large Tomodon. 



III. A single shield between the nasals ; nostrils and 

 eyes turned upwards ; latter small, with round 

 pupil , Helicops, 



Except in Tvmodon dorsatns. 



