21 
CROTALUS OREGONUS.—Holbrook. 
Plate II. 
Cuaracters. Head very large, triangular, truncated anteriorly; covered above 
with plates, and with scales on the vertex and occiput; upper jaw armed with 
fangs; 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 sub-triangular dusky spots, with white 
margins.—P]. 177. Caud. Pl. 22. Rattles, 3. 
Descrirtion. ‘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 quadri- 
lateral, and projects over the eye; there are two anterior orbital, nearly 
quadrilateral, and two posterior orbital plates, nearly of the same size and form, 
with three inferior, 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. 
