cies of chipmunks of western North
America, see the accounts of those species.

The structure of the baculum most closely resembles that of _E.
speciosus_ and the geographic ranges of these two species are in
juxtaposition.

_Specimen examined_: One from Coal Kilns, Panamint Mountains,
Inyo Co., California (CN).

#Eutamias umbrinus# (J. A. Allen)

Figures 17-18

General tone of upper parts dark; size medium to large; skull of
medium size; braincase narrowed.

Baculum: Shaft thick; keel low, 1/4 of length of tip; tip 36 to 50 per
cent of length of shaft; angle formed by tip and shaft 100 deg.; distal 1/2
of shaft markedly compressed laterally; base markedly widened; shaft
short to medium, 2.51 to 3.03 mm.

Differs from _E. bulleri_, in shaft shorter, keel smaller, ridges on
either side of tip distinct; distal 1/2 of shaft strongly compressed
laterally. Does not differ from _E. palmeri_.

For comparisons with all other species of chipmunks of western North
America, see the accounts of those species.

Specimens of _E. umbrinus montanus_ from north-central Colorado have, in
the past (Howell 1929:82), been referred to _E. quadrivittatus
quadrivittatus_. In many features these two kinds of chipmunks resemble
each other closely; their bacula, nevertheless, differ markedly (compare
figs. 8-9 with 17-18).

_Specimens examined_: 25.

_E. umbrinus umbrinus_: Wyoming: _Uinta Co._: 10 mi. S and 1 mi.
W Robertson, 8,700 ft, 1. Utah: _Uintah Co._: Paradise Park, 21
mi. W and 15 mi. N Vernal, 10,050 ft., 12.

_E. u. adsitus_: Utah: _Beaver Co._: Britts Meadow, Beaver Range
Mountains, 8,500 ft, 1 (BS). _Wayne Co._: Donkey Lake, Boulder
Mountain, 10,000 ft., 1 (UU). _Garfield Co._: Wildcat R. S.,
Boulder Mountain, 8,700 ft., 1 (UU).

_E. u. sedulus_: Utah: _Garfield Co._: Mount Ellen, Henry
Mountains, 1 (BS).

_E. u. inyoensis_: California: _Tulare Co._: Mount Whitney, head
of Big Cottonwood Creek, 2 (BS). Nevada: _Elko Co._: W side Ruby
Lake, 3 mi. N Elko County Line, 1.

_E. u. nevadensis_: Nevada: _Clark Co._: Sheep Mountains, 1
(MM).

_E. u. fremonti_: Wyoming: _Sublette Co._: 31 mi. N Pinedale,
8,025 ft., 1; 19 mi. W and 2 mi. S Big Piney, 1.

_E. u. montanus_: Colorado: _Boulder Co._: 3 mi. S Ward, 9,000
ft., 1; 1/2 mi. E and 3 mi. S Ward, 9,400 ft., 1.

#Eutamias palmeri# Merriam

Figures 17-18

General