1918 | Taylor: Revision of the Rodent Genus Aplodontia 475 
to the above considerations, however, the writer finds himself unable 
to agree with Dr. C. Hart Merriam in regarding Peters’ name as 
untenable, but is forced to consider that the balance of the evidence 
now available favors its validity. 
Specimens Examined.—A total of 75, from localities as follows: 
California: Siskiyou County—Mt. Shasta, Upper Ash Creek (alt. 7000 ft.), 
2; Mt. Shasta, Upper Mud Creek (alt. 7000 ft.), 8. Lassen County—Lassen 
Peak, upper edge Canadian zone, east side, 1; Susanville, mountains 12 miles 
west, 1. Sierra County—Salmon Lake (alt. 6600 ft.), 5. Placer County—Blue 
Cafion, 21. El Dorado County—Lake Tahoe, Emerald Bay, 3; South Fork of 
American River, 1. Alpine County—Hope Valley, 10. Mariposa County—Yo 
semite Park, East Fork Indian Cafion, 2; near Poreupine Flat, 1; head of Lyell 
Canon (alt. 9700 ft.), 5; Mt. Lyell, 4; Chinquapin (alt. 6256 ft.), 5. Mono 
County—Mammoth, 4 (2 skulls only). 
Geographic Range——The Sierra Nevada of California, from Mt. 
Shasta on the north at least to Mammoth, Mono County, on the south. 
Zonal range, Boreal. 
Cranial Characters. 
ilar, in dimensions, to Aplodontia rufa rainierit and A. 1. columbiana, 
Skull large (see measurements below), sim- 
averaging slightly larger than A. r. rufa; rostrum comparatively long, 
zygomatic arches heavy, tending to be squarer anteriorly than in any 
other aplodontia; zygomatic arches usually not so much expanded at 
the posterior root, viewing cranium on its dorsal or ventral aspect, 
as in columbiana; distinct fossa present in typical material on under 
surface of expanded portion near posterior root, unlike most examples 
of rainieri and columbiana in this respect ; postorbital processes on the 
jugal sometimes faintly indicated; temporal ridges tending to ap- 
proach to within a few millimeters of each other for their entire length, 
variously accentuated in different specimens; caliber of audital tubes 
variable, but averaging decidedly greater than in either typical rainiert 
or in columbiana, about the same as in rufa; external auditory meatus 
round or slightly flattened dorsoventrally, as in rainiert. 
External Characters—Above, in summer skins, pale ochraceous- 
buff to ochraceous-buff, in most specimens uniformly grizzled with 
blackish, and with an insprinkling of silvery tipped hairs; amount and 
concentration of black varying to a considerable extent; white spot 
at base of ear (pl. 29); underparts light mouse gray to quaker drab, 
with insprinkling of black hairs, often silvery tipped, certain speci- 
mens with indistinct wash of brown coloration near pinkish buff or 
light buff, others with a suggestion of light ochraceous-buff. Color- 
ation of winter specimens only slightly different from that in summer. 
