57 



HETERODON .—Palisot dc Bcauvais. 



Genus Heterodox. — Characters. Head large, flat; the rostral plate a trihedral 

 pyramid, with a ridge above and pointed at the tip; posterior maxillary teeth 

 largest; loral plate single; orbit surrounded with small plates, Avith the exception 

 of the superior orbital. Body and neck distensible. 



HETERODON S1MVS.—Lin7iceus, 



Plate XV. 



Characters. Head very short, flattened; snout elongated, turned up or slightly 

 recurved; azygous plate between the frontal, surrrounded by six or eight smaller 

 plates; body grey, with a vertebral series of sub-quadrate or rounded black spots 

 or transverse bars; tail fawn colour. PI. 132. Sc. 39. 



Synonymes. Hog Nose Snake, Catesby, Carol., &c., vol. ii. p. 56, pi. Ivi. 

 ( Coluber constrictor, Linnxus, Syst. Nat., ed. x. torn. i. p. 216. ) /yvo , 



Coluber simus, Linnseus, Syst. Nat., ed. xii. torn. i. p. 375. 



La camuse, Luc^plde, Hist, des Serp., torn. ii. p. 284. 



Coluber simus, Gmelin, Syst. Nat. Lin., torn. i. pars iii. p. 10S6. 



Description. The head is short, flattened and triangular, with the snout 



turned upwards, and rather recurved. The vertical plate is irregularly triangular, 



with its basis broad and turned forward, and its apex directed backwards; there 



is a single, very large quadrilateral superior orbital plate, projecting somewhat 



Vol. IV.— 8 



