696 THE MONTHLY BULLETIN. 



Type locality.— Tiptou, Tulare County, California (Merriam, 1S93, p. 129). 



Distribution. — Occupies the floor of the southern end of the San Joaquin Valley, 

 and adjacent arid hills and included vallej^s immediately to the westward (see fig. 24). 

 Life-zone Lower Sonoran. More specifically, extends from vicinity of Bakersfield 

 (S miles northeast) and Poso, in central Kern County, west to the Carrizo Plains 

 and Cuyama Valley, in southeastern San Luis Obispo County, south to the mouth 

 of San Emigdio Creek, 12 miles due east of Maricopa, Kern County, and north to 

 Huron, Fresno County, and Tipton, Tulare County. 



Specimens examined. — A total of 43, from the following localities in California. 

 Kern County : eight miles northeast of Bakersfield, 32 ; twelve miles due east of 

 Maricopa, 5 ; McKittrick, 3. San Luis Obispo County : Carrizo Plains, 3. 



The Nelson Antelope Ground Squirrel is called Antelope Chipmunk 

 by many of the people who live in the southern San Joaquin Valley. 

 No distinction is made by them between the present species and the 

 Antelope Squirrel of the Mohave and Colorado deserts. This is not 

 surprising when we consider the rather close general resemblance 

 between the two. When specimens of the two animals are in hand, 

 tone of coloration alone suffices for distinguishing them. The ground 

 color of the Nelson Squirrel is distinctly clay color, while that of the 

 Desert Antelope Ground Squirrel is pinkish buff. In the former, too, 

 the under side of the tail is crearay buff, while in the latter it is pure 

 white. In bulk the Nelson is approximately 50 per cent the larger. 



The Tehachapi Mountains on the south and the Greenhorn Mountains 

 to the east help to form a continuous barrier between the range of 

 these two near-related squirrels. We find the Nelson Squirrel to be 

 restricted for the most part to the Lower Sonoran life-zone in that 

 portion of the San Joaquin Valley which lies south of Tulare Lake. 

 It is notably numerous in the oil districts. The Nelson Squirrel may 

 be distinguished from all other rodents that occur in this region by 

 having a very short, flat-haired tail (less than 3 inches in length) and 

 by the presence of a single white stripe on each side of the body. The 

 name borne by this species was given to it by its original degcriber 

 (Merriam, 1893, p. 129) as a recognition of the contributions to mam- 

 malogy of Edward W. Nelson, now chief of the United States Bureau 

 of Biological Survey. 



During the rainy season many of the smaller streams in the southern 

 and western foothills around the San Joaquin Valley cut deep and nar- 

 row channels, but when the flood waters of such streams reach the upper 

 plains of the great valley their course is marked by broad washes with 

 low, perpendicular banks. The silt-bearing waters finally spread out, 

 forming broad, alluvial fans, and often sink into the thirsty soil before 

 they reach the lower alkaline plains. The lower reaches of such stream 

 courses, dry and desertlike most of the year, are the preferred haunts 

 of the Nelson Ground Squirrel. Here burroAvs are easily dug between 

 the hard layers of the stratified banks of the washes, affording safe 

 retreats from such predators as the coyote and badger. A luxurious 

 though brief -lived growth of vegetation results from the thorough 

 natural irrigation of the rich soil of the alluvial fans and the squirrels 

 are thus afforded an abundant food supply the rest of the year. Indi- 

 viduals and even colonies are to be found along the little gullies and 

 ridges of the upper slopes between the mouths of the streams and the 

 foothills, while a few may be found along the edges of the alkali ground 



