39 



TRIGONOCEPHALUS CONTORTRIX.— L«hhjb«s. 



Plate VIII. 



Characters. Head very large, triangular, covered with plates in frout, 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. 



Synontmes. Boa contortrix, Linnseus, Syst. Nat., vol. i. p. 373. 



Angkistrodon mokeson, Beauvais, Trans. Amer. Phil. Soc, vol. iv. p. 381. 

 Cenchris mokeson, Daiidin, Hist. Nat. des Rept, torn. v. p. 358, pi. xl. fig. 3. 

 Scytalus cupreus, Rafinesque, Am. Journ. Arts and Sci., vol. i. p. 85. 

 Scy talus cupreus, Harlan, Med. and Phys. Res., p. 130. 

 Cenchris mokeson, Harlan, 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 orbital plates nearly of the same size, the upper one triangular; the 



