115 



CROTALUS OREGANUS. 



Plate XXIV. 



Characters. Head very large, triangular, truncated anteriorly; covered above 

 with plates, and with scales on the vertex and occiput, with a broad white bar 

 between the orbits, and two others on the side of the head; one begins above the 

 pit, the other below, and are confluent behind the angle of the mouth; body thick, 

 and marked above with two zigzag white lines, that form a series of trapezoidal 

 or triangular dusky spots, with white margins. 



Description. The head is very large, triangular, broad behind, narrow and 

 truncated, or slightly rounded in front, and is proportionably longer than in other 

 Rattlesnakes; above it is covered with plates anteriorly, and with scales on the 

 vertex and occiput; the rostral plate is large and triangular, with its apex slightly 

 truncate and turned upwards; the nasal plates are two in number, the anterior is 

 quadrilateral and very large; the posterior semilunar and smaller, with a concavity 

 in front for the nostrils; the superior orbital plate is large, irregularly quadrilateral, 

 and projects over the eye; there are two anterior orbitals, nearly quadrilateral, 

 and two posterior orbitals, nearly of the same size and form, with three inferior 

 orbital plates, oblong and narrow; in front of the anterior orbital plate, and above 

 the labial range, are several small scales, making the posterior and inferior walls 

 of the deep pit between the eye and the nostril, which is completed above and in 

 front by two large plates; the nostrils are large and placed near the snout, but 

 open laterally and a little upwards;* the margin of the upper jaw is covered with 

 fifteen labial plates, those near the snout are quadrilateral, and those near the 



* Of the size of the eye and colour of the iris and pupil, and exact colour of the skin, I can 

 say nothing, as the animal above described had been for a long time preserved in alcohol. 



