17 



CROTALUS ADAMANTEV&.—Beauvais. 



Plate II. 



Characters. Head very large, triangular, rounded in front, flattened above, 

 covered with plates in front and with scales behind, and on the vertex; a deep pit 

 between the eye and nostril; upper jaw furnished with fangs; body above dark 

 brown or dusky, marked with a series of large, regularly rhomboidal spots, 

 continuous, and extending from the head to the extremity of the tail; abdomen 

 dirty yellowish-white. PI. 172. Caud. PI. 25. Rattles variable in number. 



Synontmes. Crotalus adamanteus, Beauvais, Trans. Amer. Phil. Soc, vol. iv. p. 368. 

 Crotalus rhombifer, Laireille, Hist. Nat. Rept, torn. iii. p. 197. 

 Crotalus rhombifer, Daudiri, Hist. Nat. des Rept., torn. v. p. 323, pi. Ix. fig. 22. 

 Crotalus durissus, Daudin, Gen. ZooL, vol. iii. p. 233, fig. 89, not the description. 

 Crotalus rhombifer, Mcrrein, Versuch eines Syst. der Amphib., p. 157. 

 Crotalus horridus, Harlan, Med. and Phys. Res., p. 133. 



Description. The head is enormously large, triangular, but rounded in front; 

 covered with plates anteriorly, and with scales posteriorly and on the vertex. 

 The rostral plate is small, triangular, larger below, narrowed above; the frontal 

 plates are small and quadrilateral. There are two nasal plates; the anterior 

 large, quadrilateral, and concave on its posterior margin; the posterior irregularly 

 triangular, lunated in front to complete the nostril. The superior orbital plates 

 are oval and large, the greatest extent being in the antero-posterior direction, 

 with their outer margins greatly projecting. There are two anterior orbital 

 plates; the upper larger and quadrilateral, the lower smaller. The inferior and 

 posterior walls of the orbit are made up with small plates. 

 Vol. III.— 3 



