ius_. Large series of specimens of this subgenus, from the
Arctic Slope of Alaska, are in the Museum of Natural History of the
University of Kansas. Study of these indicates that the differences,
which Rausch (_op. cit._:136) described as distinguishing his _M. m.
paneaki_ from _M. muriei_, result from differences in age of the
specimens, and possibly in part from differences in seasonal condition
of pelage. For example, Rausch thought that _M. m. paneaki_ was larger
than _M. muriei_ but our specimens reveal that such is not the case. The
measurements given below of the type specimen of _M. muriei_ (after
Nelson, original description) and measurements (in parentheses) of an
immature female (43807 K. U.) of _Microtus miurus muriei_ from Chandler
Lake, 68 deg. 12', 152 deg. 45', 2900 ft., Alaska, show close
correspondence in size. Total length, 119 (122); tail vertebrae, 24 (24);
hind foot, 20 (20); condylobasal length, 24.3 (24.5); zygomatic breadth,
10.7 (11.0); greatest width of braincase, 9.0 (9.0); length of nasals,
6.5 (6.0); basal width of rostrum, 4.0 (4.3). In the light of all of the
evidence now available, it seems best to treat _Microtus miurus paneaki_
Rausch as a synonym of _Microtus muriei_ Nelson.

Quay (Jour. Mamm., 32:95, February 15, 1951) identified fifty-eight
specimens from the Seward Peninsula of Alaska as _Microtus miurus
oreas_ Osgood. Through the courtesy of Dr. Charles P. Lyman, fifteen of
Quay's specimens in the Museum of Comparative Zoology at Harvard
College have been examined by one of us (Hall). These specimens are as
follows: Lava Lake (43378, 43379, 43381, 43382, 43386, 43467 and
43478); Mt. Boyan (43384, 43385, 43463 and 43477); Anvil Hill [= Peak],
Cooper Gulch (43377, 43464 and 43473); ----? Lake, 43383. Although we
are not prepared to say that these specimens are _M. m. muriei_, they
seem to resemble _M. m. muriei_ as closely as they do any other named
form and we here refer them to that subspecies.

The facts are that a critical taxonomic study of the American specimens
of the subgenus _Stenocranius_ is required in order to ascertain the
geographic variation. One of us (Hall) has examined the holotypes of
the kinds named from Alaska, and the material listed by R. Baker (Univ.
Kansas Publ. Mus. Nat. Hist., 5:109) of the two kinds named from
Canada. The degree and nature of the variation shown by these specimens
lead us to the conclusion that all are of a single species. If the
America