1918] Grinnell: New Mammals from the Mohave and Inyo Regions 425 
Thomomys melanotis, new species 
White Mountains Pocket Gopher 
Type.—Male adult, skull and skin (in nearly full new pelage) ; 
no. 26499, Mus. Vert. Zool.; 10,500 feet altitude on Big Prospector 
Meadow, White Mountains, Mono County, California; July 27, 1917; 
collected by A. C. Shelton; original no. 3402. 
Diagnosis—A Thomomys with characters of the ‘‘perpallidus 
group’’ in part and of the ‘‘alpinus group’’ in part (see Bailey, 1915, 
pp. 33, 63, 68). General coloration very pale, almost identical with 
that in 7. perpallidus perpallidus, differing from that form only in 
more dusky nose and mouth and in more extensive, slaty black, ear- 
patch. Ear extremely small, rounded, and densely clothed with fine 
black hairs. General size medium, about as in 7. alpinus alpinus. 
Skull relatively narrow, and with slender rostrum and unaccentuated 
ridges, thus resembling alpinus; but dentition lighter, interorbital 
constriction narrower, and auditory bullae much larger. 
Comparisons.—In coloration, much paler and grayer than any of 
its geographical neighbors (Thomomys perpallidus perpes, T. scapterus, 
T. operarius, and T. alpinus alpinus). Differs from perpes otherwise 
in smaller and more hairy ears, extensively black ear-patch, lighter 
skull, narrower interorbital constriction, narrower rostrum, slenderer 
zygomata, much smaller teeth, and larger auditory bullae. Differs 
from scapterus in larger size, extensively black ear-patch, more widely 
and more squarely spreading zygomatic arches, broader brain-ease, 
much longer nasals, and larger auditory bullae. Differs from operarius 
in conspicuously black-haired ears, extensive black ear-patch, lighter 
and slenderer skull, much narrower rostrum, more projecting incisors, 
much lighter dentition, constricted nasals, narrower interorbital con- 
striction, and more inflated auditory bullae. Differs from alpinus in 
more extensive black ear-patch, less projecting incisors, much smaller 
molar teeth, narrower interorbital constriction, and much larger 
auditory bullae. 
Measurements.—See Table 2; compare with those of various gophers 
as given in Bailey (1915). 
Distribution —The nine specimens secured (see table) were all 
taken in the Canadian and Hudsonian life-zones, 10,000 to 10,500 feet 
altitude, on, and within three miles of, Big Prospector Meadow, White 
Mountains, Mono County, California. 
Remarks.—The writer confesses his inability, with the material now 
available, to determine satisfactorily the relationships of this new 
gopher. It was thought at first to belong unquestionably to the alpinus 
group and to constitute a sequestered and far differentiated form 
within that series. A few gophers from the vicinity of Benton, Mono 
County, and elsewhere in the northern end of Owens Valley, however, 
show characters which make it seem possible that melanotis has been 
derived from the lowland perpallidus stock through altitudinal in- 
vasion. Further acquisition of specimens from the Inyo region will 
be needed to clear up the question. 
