1918] Grinnell: New Mammals from the Mohave and Inyo Regions 427 
Thomomys perpallidus mohavensis, new subspecies 
Mohave River Pocket Gopher 
Type—Male adult, skull and skin; no. 4639, Mus. Vert. Zool.; 
Mohave River bottom, 2700 feet altitude, near Victorville, San Ber- 
nardino County, California; December 26, 1904; collected by J. 
Grinnell and J. Dixon; original no. 906. 
Diagnosis—A Thomomys of the ‘‘perpallidus group’’ (see Bailey, 
1915, pp. 33, 68). Resembles 7. perpallidus perpallidus eranially, but 
color much darker above, bright cinnamon-buff (of Ridgway, 1912, 
pl. 29), and tail shorter; differs from 7. p. perpes (topotypes) in 
lighter, more cinnamon tone of coloration dorsally, in slightly larger 
size, in greater and squarer spread of zygomatic arches, in more pro- 
jecting incisors, and in much larger auditory bullae. 
Measurements.—See Table 3. 
Distribution —Abundant along the bottomlands of the Mohave 
River, in San Bernardino County, at least from Victorville down 
(north) to Barstow; also, transversely, along the southern rim of the 
Mohave Desert, from Cushenbury Springs, San Bernardino County, 
west at least to Fairmont, Los Angeles County. 
Remarks—As already stated, by Bailey (1915, p. 69), pocket 
gophers are not continuously distributed over the desert areas of the 
Southwest. Wide areas are unrepresented at all, these animals thus 
occurring in more or less remotely isolated colonies, usually where 
permanent moisture produces a continuous growth of edible plants. 
The larger valleys, like those of the Mohave and Owens rivers, well 
separated from one another by desert reaches, have evidently served 
as effective differentiation centers, and we find several distinguishable 
races of the pocket gopher accordingly. It seems equally true that 
some of the higher and more isolated of the mountain ridges of the 
TABLE 3 
MEASUREMENTS, IN MILLIMETERS, OF EIGHT ADULT SPECIMENS OF Thomomys per- 
pallidus mohavensis, ALL COLLECTED BY J. GRINNELL AND J. DIXON IN THE 
VICINITY OF VICTORVILLE, SAN BERNARDINO COUNTY, CALIFORNIA 
: a & 2 i, 
a 5 ee LE Es 
ies ee) ae ee ee Bea eee 
eee Sex Date = = is ge Be a7 58 a ieee Ba 
4639" of Dee. 26, 1904 235 75 Bal 36.4 alfay-45) 26.1 20.7 6.4 8.0 
4646 dé Dee. 29, 1904 227 76 30) 33.0 12.2 23.0 19.5 6.6 7.8 
4660 3 Dee. 31, 1904 223 75 28 34.9 12.9 24.4 20.1 6.2 7.6 
4661 fof Dee. 28, 1904 228 66 30 37.0 ye 27.8 21.9 6.7 8.1 
4644 2 Dee. 31, 1904 195 62 28 30.6 10.0 22.3 18.1 6.5 7.6 
4647 2 Jan, 1,1905 212 60 29 32.3 13.0 23.5 19.8 6.9 Tei 
4648 io) Dee. 27, 1904 230 69 30 2.2 12.4 23.4 20.1 6.5 8.0 
4650 g Dee. 27, 1904 210 70 29 31.9 13.0 23.7 20.0 6.7 Ti 
1 Type. 
