228 CALIFORNIA ACADEMY OF SCIENCES. 



five black rings or cross-bars. The lower surfaces are 

 yellowish, often faintly clouded with light brown. 



Length to anus 935 1080 



Length of tail to rattle 55 75 



Distribution. This, the largest rattlesnake of the 

 West, was first described from a specimen of unknown 

 origin. It has since been found on the western slopes 

 of San Diego and Riverside Counties, at Twin Oaks, 

 San Jacinto, and De Luz. 



