48. CROTALUS 937 
however, for we have a specimen of the scutulatus type from 
the desert near Tucson, Pima County. 
In Lower California, this species is common on Los 
Coronados Islands (South Island), and has been taken in 
the San Pedro Martir Mountains, and at San Jose in the 
northern part of the peninsula. 
Remarks.—This rattlesnake is closely related to C. con- 
fluentus and C. emyo. It is the common rattlesnake of the 
far west and seems adapted to very varied conditions of soil, 
vegetation, climate and altitude. Its coloration is very 
variable, both in shade and pattern. Occasionally a few of 
the distal caudal cross-bars are blackish or even black. Some 
specimens from the desert resemble C. atrox in general 
appearance, but may be recognized by the position of the 
stripes on the side of the head. These specimens sometimes 
have large plates on the anterior part of the head. Such 
was the type of Kennicott’s C. scutulata, although more re- 
cent authors usually have applied this name to specimens of 
C. atrox. It is possible that scutulatus should be regarded 
as a desert subspecies. The snakes of Utah, Nevada and 
eastern California may perhaps deserve similar treatment 
since their color pattern is usually different from that of 
typical C. oreganus. (See plate 102 in which figure 2 shows 
the Great Basin type of coloration). 
Habits.—Dr. and Mrs, Grinnell have published the fol- 
lowing notes on this rattlesnake, as observed by them in Los 
Angeles County and in the San Bernardino Mountains: 
“Rattlesnakes are undoubtedly becoming more and more 
rare in the settled parts of the County, where formerly they 
were often met with. One was seen on the bluff west of San 
Pedro near Point Fermin, September 15, 1906; and a few 
have been reported the past year or two from the hills west 
