16. C ROT A LI DM 



snake occupies the area bounded in the East by the ninety- 

 sixth meridian and the Upper Missouri Valley } by the main 

 divide of the Rocky Mountains in the Westj by the thirty- 

 third parallel in Texas and the Mexican boundary further 

 west in the South; and by the fiftieth parallel in the north. 

 Although the main divide of the Rocky Mountains in this 

 northern region seems to be the limit of its extention to the 

 west, yet in at least one place where there is no high crest to 

 obstruct its passage across, it has been found on the western 

 slope, viz.; at Lemhi, Idaho."* It has not been taken in 

 Nevada, nor in any of the Pacific States. Specimens have 

 been recorded from a number of localities in Arizona, as. 

 Cave Creek, Maricopa County, Wilcox, Cochise County, 

 Apache, Navajo County, Camp Grant, Graham County, and 

 Fort Buchanan, Santa Cruz County. 



Remarks. — The Arizonan specimens which I have seen 

 are not really typical Crotalus confluentus. Nevertheless they 

 seem to be more like that species than like Arizonan speci- 

 mens of C. oreganus. It is possible that they are merely 

 abnormal individuals of the latter species, but until more 

 specimens have been secured it seems best to continue to re- 

 gard them as C. confluentus. 



2U. Crotalus oreganus Holbrook 



Pacific Rattlesnake 



Plates 98, 101, 102, 111, and 112 



Crotalus oreganus Holbrook, N. Amer. Herpet., Ed. i, Vol. 4, 1840, 

 p. 115, pi. 29 [=XXIV] (type locality, banks of the Oregon or 

 Columbia River); Gill, Science, Ser. 2, Vol. 17, 1903, p. 910; 

 Grinnell & Camp, Univ. Cal. Publ. Zool., Vol. 17, No. 10, 

 1917, p. 194; CowLES, Journ. Entomol. & Zool., Pomona College, 

 Vol. XII, No. 3, 1920, p. 66; Stephens, Trans. San Diego Soc. 

 Nat. Hist., Vol. Ill, No. 4, 1921, p. 65; Van Denburgh & Slevin, 



•Stejneger, Report U. S. Nat. Mus. for 1893. 



