Oc. Papers, Cat. Acap. Sci., VoL. X [Van Denpurcu Pirate 101 
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Fig. 1. Crotalus confluentus, Prairie Rattlesnake 
Section of skin of specimen collected at Cave Creek, Maricopa County, Arizona, 1910 
Fic. 2. Crotalus oreganus, Pacific Rattlesnake 
Section of skin of specimen collected on Mount Lemmon, Santa Catalina Mountains, Pima 
County, Arizona, June, 1912 
