CROCODILIANS, LIZARDS, AND SNAKES. 1183 



The distribution of this species is commented on by Dr. Stejneger in 

 his report on the reptiles of the Death Valley expedition as follows: 



The "tiger rattler," of which the expedition has l)roiight home quite a series, is oue 

 of the rarest species in collections. Discovered during tlie survey of the boundary 

 between the United States and Mexico, and described by Kennicott, the habitat of 

 the species was given in general terms as "Deserts of Gila and Colorado," but I can 

 find no evidence of specimens recorded from anywhere except from the Sierra del 

 Pozo Verde,' in Arizona. A specimen was afterwards collected by Dr. Irwiu at Fort 

 Buchanan, Arizona, and recorded by Dr. Yarrow in his Catalogue of the Rejttiles and 

 Batrachians in the U. S. National Museum (No. .5271). Dr. .J. G. Cooper has since 

 enumerated C. tujris from the California side of the "Colorado Valley," but whether 

 he based his record upon specimens actually collected (in which case, probably near 

 Fort Mohave), or only upon the general statement in the report of the Mexican 

 Boundary Survey, I do not know. 



It does not appear to have been collected by any of the many parties of the Pacific 

 Railroad Surveys, nor was it brought home by the herpetologists of the Wheeler 

 expedition west of the one hundredth meridian. 



The extension of its known range by the present expedition is therefore very 

 material, and is the more interesting since it was found almost over the entire desert 

 area visited. So far from being restricted to the Colorado Valley proper, as sur- 

 mised by Dr. Cooper, it seems to be chiefly confined to the desert mountain ranges, 

 in which it ascends to a considerable altitude, as shown by the table below, while 

 horizontally its range has been extended over quite a considerable area of southern 

 Nevada. 



A study of the present series convinces me that the nearest affinity of the " tiger 

 rattler" is with the true Crotaliis conjluentus of the plains, in spite of the rather 

 striking and, in many respects, peculiar aspect of the former. 



Dr. Merriam gives the following note in his report on the results of 

 the Death Valley expedition : 



The known range of this exceedingly rare rattlesnake has been greatly extended 

 by the expedition, specimens having been secured at frequent intervals from Owens 

 Valley, in California, to the Great Bend of the Colorado, on the boundary between 

 Nevada and Arizona. It was usually found in rocky places in the desert ran<'es — 

 rarely in the intervening valleys. 



When i)assing through Emigrant Canyon, in the Panamint Mountains, in California, 

 April 15, two large rattlesnakes of this species were killed at one shot by Mr. 

 Stephens, at an altitude of 1,400 meters (1,600 feet). They were on a ledge of rock, 

 and were standing erect with their heads near together, apparently playing. In Indian 

 Spring Valley, north of the Charleston Mountains, in Nevada, one was found in a 

 wood rat's nest that was dug open to secure a large scaly lizard {Scelojwrus magister) 

 which had taken refuge there. Its stomach contained a kangaroo rat {Dqiodomi/s) 

 and a pocket mouse ( Per of/nat hits), indicating nocturnal habits. Others were killed 

 in the upper part of Vegas Valley (near Cottonwood Springs) and Vegas Wash, 

 Nevada, and in Owens Valley (on Independence Creek), Coso Valley, the Argus Range 

 Slate Range, Pauamint Range,»and (Grapevine Mountains, California. In the Argus 

 Range nineteen were killed in or near Shepherd Canyon, during the latter part of 

 April and first week of May, by Dr. Fisher's party. 



'The name is written both Sierra del Pozo Verde and Sierra Verde in the Rept. 

 U. S. and Mex. Bound. Snrv. (See I, Pt. 1, p. 121, and Pt. 2, p. 70). This range 

 is situated on the boundary between Arizona and Sonora, nearly due south of Babo- 

 quivari Peak, and about 50 miles northwest of Nogales. A spring known as Agua 

 del Pozo Verd«! (Green Well) is situated at the foot of the western slopo near the 

 southern end of the range. 



