4-8. 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. enyo. 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 1 02 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, 1906j and a few 

 have been reported the past year or two from the hills west 



