440 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4TH SEr. - 
EXPLANATION OF PLATE XX 
Crotalus oregonus Holbrook: Pactrrc RaTTLESNAKE—Photograph from 
alcoholic specimen (No. 34683) collected on Mt. Lemon, Santa Catalina 
Mountains, Arizona, June 12, 1912. 
