vaemus_ on the eastern Asiatic mainland are subspecies of one or
another of the species of western Europe, _A. flavicollis_ or _A.
sylvaticus_. Ellerman (in Ellerman and Morrison-Scott, 1951:564) states:
"The majority of the forms I distribute in a somewhat arbitrary manner
between _sylvaticus_, average smaller skull, and _flavicollis_, average
larger skull; occurring together nearly throughout the Palaearctic. I
feel fairly sure that there are some errors of judgment in my
arrangement, and equally sure that there is no other way to define
species in this very large and difficult group." I have compared the
specimens of _peninsulae_ available to me from central and southern
Korea with specimens of _A. f. flavicollis_ from Denmark, Germany and
Sweden and find, although the two are similar in many ways, that
_peninsulae_ differs from _flavicollis_ in several important characters:
Mammae 1-2=6 in _flavicollis_, and 2-2=8 in _peninsulae_; incisive
foramina reaching level of alveoli of M1, or nearly so, in
_flavicollis_, but ending conspicuously short of that level in
_peninsulae_; posterior palatine foramina large in _flavicollis_ and
opposite a point where M1 and M2 meet, but small in _peninsulae_ and
situated farther back on the palate, opposite M2. Moreover, _peninsulae_
lacks the characteristic buffy throat patch of _flavicollis_, has a much
reduced posterointernal cusp on the M1, a relatively (frequently
actually) larger M3 and, on the average, a broader mesopterygoid fossa.
In view of these differences, all of which appear to be constant, I
consider _peninsulae_ specifically distinct from _flavicollis_.
Throughout its known geographic range (see below) _peninsulae_ is
evidently confined to wooded terrain, either scrub or brush types or
forested areas, and the vernacular name wood mouse, therefore, seems
appropriate for this species.

The type specimens of _Apodemus praetor_ Miller (type from Sungari
River, 60 mi. SW Kirin, Manchuria) and _Apodemus nigritalus_ Hollister
(type from Tapucha, Altai Mountains, Siberia) agree with _peninsulae_ as
concerns the above characters and differ from it only in minor external
and cranial features. They are, therefore, here considered as subspecies
of the latter.

Ellerman (1949:32) and Ellerman and Morrison-Scott (1951:567) regarded
_nigritalus_, like _peninsulae_, as a subspecies of _flavicollis_. The
subspecies _praetor_, on the other hand, has generally been regarded as
a synon