but failed to mention the specimens recorded by Bailey,
and thus their subspecific identity is in doubt. We find that _T. b.
mohavensis_ differs from _T. b. perpes_ in more pallid color (light
yellowish as opposed to dark rufescent) larger size, larger and more
angular skull, angular (as opposed to more evenly bowed) zygomatic
arches, larger and deeper audital bullae, narrower interpterygoid space,
and proportionately greater mastoidal breadth. In external measurements,
size and angularity of skull, width of interpterygoid space and
angularity of the zygomatic arch, the specimens from Lone Willow Spring
seem to be intermediate between the two subspecies, but perhaps show
more resemblance to _T. b. mohavensis_. Otherwise, the specimens closely
resemble _T. b. mohavensis_ to which they are here referred. The
specimens provide a northern marginal record of occurrence for that
subspecies.

Other specimens recorded as _T. b. perpes_ by Bailey (_loc. cit._) from
Grapevine Ranch, California, have also not been mentioned in later
publications although, from a geographic standpoint, they might be
better referred to either _Thomomys bottae pascalis_ or _T. b.
mohavensis_. Comparison of specimens of _T. b. mohavensis_ and _T. b.
pascalis_ from various localities show _T. b. pascalis_ to be larger
(including the skull), darker, and to possess a more nearly vertical
occipital plane, wider-spread but less angular zygomatic arches, less
inflated tympanic bullae, wider braincase (which consequently appears to
be less inflated), proportionately longer and slenderer rostrum, and
broader nasals distally. Cranially, _T. b. pascalis_ differs from _T. b.
perpes_ in essentially the same ways, but to an event greater degree. In
color, _T. b. pascalis_ differs from _T. b. perpes_ in being duller,
less rufescent.

The series of four specimens, in the U. S. Biological Surveys
Collection, from Grapevine Ranch clearly are not referable to _T. b.
perpes_. They do, however, agree with _T. b. mohavensis_ in all
essential particulars except that in two of the four specimens the
braincase is wider and the nasals are wider distally. This width is
evidence of intergradation with _T. b. pascalis_. Seemingly, then, they
are best referred to _Thomomys bottae mohavensis_.

~Thomomys bottae muralis~ Goldman

When Goldman (Jour. Washington Acad. Sci., 26(3):112, March 15, 1936)
described and named this pocket gopher from Arizona, he arranged it as a
full