69 



TRIGONOCEPHALUS CONTORTRIX. 



Plate XIV. 



Characters. Head very large, triangular, covered with plates in front, and on 

 the vertex, with scales behind; a pit between the eye and nostril; upper jaw with 

 poisonous fangs; body thick, light hazel-nut brown, with transverse bars of dark 

 brown, narrowest on the mesial line, broader and bifurcating on the flanks; tip of 

 the tail corneous. PI. 150, caud. pi. 42, sc. 4. 



Svnonymes. Boa contortrix, Lin., Syst. Nat, vol. i. p. 373. 



Angkistrodon mokeson, Beauv., Tran. Amer. Phil. Soc, vol. iv. p. 381. 

 Cenchris mokeson, Daud., Hist. Nat. des Rept, torn. v. p. 35S, pi. lx. fig. 3. 

 Scytalus cupreus, Rafin., Am. Jour. Art. and Sci., vol. i. p. 85. 

 Scytalus cupreus, Harl., Med. and Phys. Res., p. 130. 

 Cenchris mokeson, Harl., Med. and Phys. Res., p. 128. 

 Copperhead, Vulgo. 



Description. The head is very large, triangular, and broadest posteriorly; the 

 mouth large, with the upper jaw strong, and furnished with poisonous fangs; the 

 vertical plate is regularly pentagonal, with an acute angle directed backwards; the 

 superior orbital plates are irregularly triangular, with their apices turned inwards, 

 and their bases outwards, projecting over the eye; the occipital are rhomboidal; 

 the frontal plates are large and quadrilateral; the anterior frontal are of the same 

 form, but smaller; the rostral is large, triangular, with its basis downwards, and 

 its apex upwards and truncate. There are two nasal plates, the anterior 

 quadrilateral with its posterior margin hollowed, the posterior trapezoid with 

 its anterior border lunated to complete the nostril. There are three posterior 



