228 CALIFORNIA ACADEMY OP SCIENCES. 



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

 yellowish, often faintly clouded with light brown. 



Length to auus 9.35 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. 



