918 16. CROTALIDA 
210. Crotalus tortugensis Van Denburgh & Slevin 
Torruca Istanp Diamonp RatTTrLESNAKE 
Crotalus tortugensis Van DensurcH & Stevin, Proc. Cal. Acad. Sci., 
Ser. 4, Vol. XI, 1921, p. 398 (type locality, Tortuga Island, 
Gulf of California, Mexico). 
Description —tLarge. Head broad, flat-topped, varying 
in outline according to position of fangs. Rostral usually 
higher than wide, in contact with anterior nasal. Two nasals. 
Usually two preoculars and two to four internasals. A large 
scale just in front of supraocular. Supraocular large but not 
raised into a horn-like process; separated from its fellow 
by from four to five irregular rows of scales. About 14 to 
17 superior and 14 to 18 inferior labials; first pair of latter 
usually meeting on median line in front of a single pair of 
genials, but rarely divided. About three or four rows of 
scales between supraoculars and eye. Scales in 27 rows, of 
which one or two on each side are smooth. Gastrosteges 
varying from 180 to 190. Urosteges 16 to 25. 
The general color is yellowish, brownish or pinkish, with 
a series of large, darker brown blotches along the back These 
blotches often are not well defined, especially posteriorly, 
are not completely enclosed in light borders, and show much 
of the punctulate or pepper-and-salt style of coloration. The 
margins of the rhombs are much darker than the central por- 
tions which usually include on each side a group of scales 
as pale as the general ground color. These light areas in 
the rhombs may spread and be connected across the middle 
line. The sides are more or less indefinitely spotted or 
blotched with dark brown in the same punctulate manner, 
and sometimes show pinkish shades. The head is nearly 
unicolor above or mottled with darker, with a light streak 
across the supraocular plate. A yellowish or whitish stripe 
runs across the side of the face from the preocular plates to 
