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THE MONTHLY BULLETIN. 



DEATH VALLEY ROUND-TAILED GROUND SQUIRREL. 

 Citellus tereticaudus eremonomus Elliot. 



Other names. — Death Valley Spermophile ; Citellus eremonomus. 



Field characters.— Exactly as for the Yuma Round-tailed Ground Squirrel. 



Description.— -As for the Yuma and Palm Springs Round-tailed Ground Squirrels, 

 but coloration decidedly darker than in either, near wood brown. This feature is 

 characteristic in all of the eight skins of eremonomus at hand. 



Color variations. — The time of the spring molt is indicated by a specimen of date 

 April 10, in which new summer pelage shows on the head and rump ; an example of 

 May 3 is in absolutely new summer pelage except, of course, for the tail. One speci- 

 men has a bobbed tail, with an abnormal tuft of hairs at the end, showing con- 

 spicuously a band of black and then a terminal band of white. Most of the skins 

 show a curious spotting of the rump which is clearly not due to color markings on 

 the hairs, but to places where hairs are absent, so that the dark-colored skin and dark 

 bases of adjacent hairs show through. These may indicate scars from insect bites. 



Measurements. — Average and extreme measurements, in millimeters, of eight adult 

 female specimens from Death Valley are as follows: total length, 249 (240-255) ; 

 tail vertebrae, 91 (87-93) ; hind foot, 35 ( 34-36) ; ear from crown, 2.1 (2.0-3.0) ; 

 greatest length of skull, 36.0 (34.8^-36.6) ; zygomatic breadth, 22.5 (22.0-23.4) ; 

 interorbital width, 8.7 (8.3-8.8). No males are available. 



Weights. — Average and extreme weights, in grams, of eight adult females from 

 Death Valley are as follows: 144.3 (121-158). The average, in ounces, is 5.1. 



Type locality.— Furnace Creek [Ranch], Death Valley, Inyo County, California 

 (Elliot, 1903, p. 243). 



Distribution area. — Floor of Death Valley, in Inyo County. Life-zone, Lower 

 Sonoran. Only known locality of occurrence, vicinity of Furnace Creek Ranch 

 (Greenland Ranch) , — 240 to — 175 feet altitude. Apparently cut off from its nearest 

 relative, tereticaudus proper, by the elevated rim of the Death Valley basin. 



Specimens examined.— A total of 8, all from the near vicinity of Furnace Creek 

 Ranch, — 178 feet, Death Valley, Inyo County. 



As far as known, this race of Round-tailed Ground Squirrel is limited 

 in its distribution to the bottom of the deep sink known as Death Valley, 

 and even there to the belt of mesquites immediately around the margin 

 of the alkali flats at the lowest level. The entire habitat of this Death 

 Valley subspecies thus lies below sea level, a distinction probably not 

 shared by any other rodent in America. 



Our experience with this squirrel was obtained during April and 

 early May, 1917, in the immediate vicinity of old Furnace Creek Ranch, 

 now known as Greenland Ranch. The animals at the time of our visit 

 were not invading the cultivated land, though we were assured by the 

 foreman that they had come into the alfalfa fields in previous seasons. 

 Since this was the type locality of the subspecies, special efforts were 

 made to obtain a series of specimens. The animals were not abundant, 

 and proved practically impossible to trap. Shooting was resorted to, 

 though with but little better results. The following notes were made 

 on April 10 by the senior author while hunting them. 



During a two hours hunt at midday at least five individuals were 

 heard on the mesquite-crowned sand dunes within a mile southwest of the 

 ranch. The warmth had seemingly brought them out, for the previous 

 two or three days had been relatively cool, and none had been seen. 

 A temperature of over 100° in the shade seemed to be necessary to 



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