79. HETERODOX. !.">:{ 



Total length 285 millim. ; tail 45. 

 Southern Brazil. 



a-b. cf (V. 188; C. 33) Cio Cahy, near S. Dr. H. v. Ihering [C.]. 

 & hgr. (V. 133 ; C. 27). Joao de Monte 

 Negro. 



3. Lystrophis semicinctus. 



rixlon semicinctus, Dum. fy Bibr. vii. p. 774 (1854) ; Jan, Arch. 

 Zool. Anat. Phys. ii. 1863, p. 224, and Icon. Gtn. 48, pi. iii. tig. 5 

 (1876). 

 pulcher, Jan, II. cc. p. 222, Icon. 11, pi. iv. fig. 1 (1865). 



Frontal as long as broad, shorter than its distance from the end 

 of the snout, as long as the parietals ; usually an azygous shield 

 separating the praefrontals ; one or two prae- and two postoculars ; 

 temporals 1 + 2; eight upper labials (exceptionally seven), fourth 

 and fifth entering the eye : four or five lower labials in contact 

 with the anterior chin-shields ; posterior chin-shields small. Scales 

 in 21 rows. Ventrals 153-173; anal divided ; subcaudals 25-41. 

 End of tail rounded off. Above with black cross bars disposed in 

 pairs, the interspace between the two yellow, that between the pairs 

 red ; the red scales, and sometimes also the yellow ones, with a black 

 spot or a black edge ; head variegated with black ; a black band 

 between the eyes ; belly black, usually yellow on the sides. 



Total length 660 millim. ; tail 80. 



Uruguay, Bolivia, Argentina, Northern Patagonia. 



a. rf (V. 166 ; C. 30). Uruguay. 



b. 2 (V. 163; C. 2(5). Rio de Cordova, E. Fielding, Esq. [P.]. 



Argentina. 



c. rf (V. 162 ; C. 36). Catamarca. Lord Dormer [P.], 



d-e. Yg. (V. 159, 154 ; Argentina. E. \V. White, Esq. [C.]. 



C. 33, 30). 

 f-ff- 2 (V. 160; C. 27) Patagonia. 



&hgr. (V. 162 ;C. 25). 



79. HETERODON. 



Heterodon, Latreille, Hist. Kept. iv. p. 32 (1800) ; Baird $ Gir. 



Cat. N. Am. Rept. p. 51 (1853) ; Cope, Proc. U.S. Nat. Mas. xiv. 



1892, p. 642. 

 Heterodon, part., Schleg. Phys. Serp. ii. p. 96 (1837) ; Dum. $ Bibr. 



Erp. Gtn. vii. p. 764 (1854) ; Giinth. Cat. Col. Sn. p. 82 (1858) ; 



Jan, Arch. Zool. Anat. Phys. ii. 1863, p. 218; Bocourt, !/ 



Mes., Rept. p. 603 (1886). 



Maxillary very short, shorter than the ectopterygoid, with 6 to 

 11 teeth, followed, after an interspace, by a pair of strongly enlarged 

 fangs ; mandibular teeth subequal. Head scarcely distinct from 

 neck ; snout very short, projecting, cuneiform ; rostral very large, 

 trihedral, with sharp A-shaped edge ; eye moderate, with round 



