63 
HETERODON NIGER.—Catesby. 
Plate XVI. 
Cuaracters. Head flattened, triangular, covered with plates in front and with 
scales behind; snout pointed, and turned upwards at the tip; whole animal black 
above and bluish slate-colour below. Pl. 127. Sc. 50. 
Synonymes. Black viper, Catesby, Carol., &c., vol. ii. p. 44, pl. xliv. 
Scytale niger, Dawdin, Hist. Nat. des Rept., tom. v. p. 342. 
Coluber cacodemon, Shaw, Gen. Zool., vol. iil. p. 377, pl. cil. 
Pelias niger, Merrem. 
Coluber thraso, Harlan, Med. and Phys. Res., p. 120. 
Scytalus niger, Harlan, Med. and Phys. Res., p. 130. 
Heterodon niger, Zroost, Ann. Lye. Nat. Hist. N. Y., vol. ili. p. 186. 
Description. The head is large, flattened, triangular, broader behind, narrow 
and pointed in front, covered with scales posteriorly and with plates anteriorly. 
The vertical plate is pentagonal, broadest in front; the superior orbital are 
nregularly quadrilateral, broadest behind, with their outer margins projecting. 
The occipital plates are rhomboidal; the frontal elongated, hexagonal, and narrow 
externally; the anterior frontal triangular, their bases inwards, and their apices 
reaching almost to the nostrils; between their bases is an additional long, narrow 
plate, elevated above to forma ridge. The rostral plate is triangular, the base 
directed downwards, the apex upwards and pointed, with an elevated ridge on its 
upper surface. The nasal plates are two; the anterior is round in front and 
above, and concave behind; the posterior is narrow and Junated in front, to 
complete the opening of the nostril. The loral plate is single, pentagonal, and 
