FAMILY CROTALIDiE. 53 



FAMILY CROTALID^. 



With poisonous movable fangs in the upper jaw ; no other teeth in the upper jaw . A pit or 

 fossa hetioeen the eye and nostril. Terrestrial. 



Obs. In tliis State we have but two venomous serpents belonging to this family; and neither 

 of them, except in the unsettled districts, are numerous. 



GENUS TRIGONOCEPHALUS. Oppel. 



Head large, triangular ; covered luith plates in front and on the vertex to behind, the orbits, 

 and beyond, this with scales. A deep fosset between the eyes and nostrils. Body robust. 

 Tail with plates, simple, unarmed.; its plates occasionally divided. 



THE COPPER-HEAD. 



Trigonocephalus contortrix. 



PLATE IX. FIG. 18, a. Summit of the heae. - (CABINET OF THE LYCEUM.- 



Boa contortrix. LiN. Syst. Nat. 12 Eri. p. 373. 



Anghstrodon mokeson. Pal. de Beauv. Am. Transact. Vol. 4, p. 381. 

 Ceiickns coKturtnx. Daud. Hist. Reptiles, Vol. 5, p. 358, pi. 50, fig. 25, (Head.) 

 Scyiale cuprtiis. Harl. Med. and Phys. Res. p. 120. 



Tngomcephahis contortrix. Holbrook, N. Am. Herpetology, Vol. 2, p. 69, pi. 14, Ed. prima ; Vol. 3, p. 39, pi. 8, Ed. 

 secunda. 



Characteristics. Copper-colored. Reddish brown blotches over the back, dilated on the sides. 

 Senes of irregular rounded black blotches on each side of the abdominal 

 plates. Length two to three feet. 



Description. Body robust and thick, and covered with oblong hexagonal carinate scales ; 

 those on the flanks larger and smooth. The posterior part of the head covered with smooth 

 oval scales, which become carinate on the neck. Head large and very distinct from the neck, 

 (in the plate, the head is represented disproportionately small,) and flattened above. Rostral 

 plate emarginate beneath ; the two pair of frontal plates four-sided, the posterior pair largest ; 

 supra-orbital plate oblong, obscurely triangular, prominent over the eyes ; vertical plate sub- 

 pentagonal, with an acute process directed backwards, and separating the occipital pair. 

 Rostral plate large, triangular. The fosset or pit lies between the second labial and one of 

 the anterior orbitals. Mouth very large, with long yellowish white venomous fangs in the 

 upper jaw. Abdomen wide and flat. Tail short, one-eighth of the total length, tapering 

 rather suddenly, and ending in a solid horny tip : the caudal plates irregularly bifid ; and 

 this division occurs either at the commencement, middle, or more rarely near the end- of the 

 tail. Ventral plate wide, subquadrate. 



