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Comments on
the Taxonomy and Geographic Distribution
of North American Microtines



BY

E. RAYMOND HALL AND E. LENDELL COCKRUM

University of Kansas Publications
Museum of Natural History
Volume 5, No. 23, pp. 293-312
November 17, 1952



University of Kansas
LAWRENCE
1952

UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, A. Byron Leonard,
Edward H. Taylor, Robert W. Wilson

Volume 5, No. 23, pp. 293-312
November 17, 1952

UNIVERSITY OF KANSAS
Lawrence, Kansas

PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1952



Transcriber's Note: The symbol "^" in some numbers in Table I is used
to indicate that the number following it are printed in superscript.



Comments on
the Taxonomy and Geographic Distribution
of North American Microtines

BY

E. RAYMOND HALL and E. LENDELL COCKRUM


In preparing maps showing the geographic distribution of North American
microtines, conflicting statements in the literature and identifications
that, if accepted, would result in improbable geographic ranges have
led to the examination of pertinent specimens with the results given
below. The studies here reported upon were aided by a contract between
the Office of Naval Research, Department of the Navy, and the
University of Kansas (Nr 161-791), by funds provided by the University
of Kansas from its Research Appropriation, and by grants for
out-of-state field work from the Kansas University Endowment
Association. Grateful acknowledgment is made to persons in charge of
the collections at each of the following institutions for permission to
use the collections under their charge: Biological Surveys Collection,
United States National Museum (herein abbreviated USBS); California
Museum of Vertebrate Zoology (MVZ); Chicago Natural History Museum
(CNHM); University of Kansas Museum of Natural History (KU); Museum of
Comparative Zoology (MCZ); United States National Museum (USNM);
Department of Economic Zoology, University of Wisconsin (UWDEZ); and
Zoological Museum, University of Wisconsin (UWZM).


    Synaptomys cooperi saturatus Bole and Moulthrop

    1942. _Synaptomys cooperi saturatus_ Bole and Moulthrop, Sci.
    Publs. Cleveland Mus. Nat. Hist., 5:149, September 11, type from
    Bloomington, McLean County, Illinois.

When Bole and Moulthrop named _Synaptomys cooperi saturatus_, with type
locality in Illinois, they, in effect, divided the geographic range of
_Synaptomys cooperi stonei_ into two parts (see A. B. Howell, N. Amer.
Fauna, 50:10 (fig. 2), August 5, 1927) since Bole and Moulthrop (_op.
cit._) did not assign to any subspecies the specimens from southern
Wisconsin that Howell (_op. cit._) had identified as _S. c. stonei_.
Bole and Moulthrop's inclusion in their newly named subspecies of a
specimen from as far west as East Columbia, Missouri, left in doubt the
subspecific identity of specimens from Iowa and a specimen from
Arkansas. Howell (_op. cit._) had assigned this material from Iowa and
Arkansas to _S. c. gossii_.

Howell recognized that the one individual (168266 USBS) from Lake City,
Arkansas, was too young to be identified to subspecies with certainty
and assigned the specimen to _S. c. gossii_ "upon geographical grounds"
(_op. cit._:19). Keith R. Kelson and one of us (Hall) compared this
specimen with pertinent materials. As a result of this comparison we
refer the specimen, on the same grounds employed by Howell, to
_Synaptomys cooperi saturatus_.

Specimens from approximately the southern half of Wisconsin (from Kelly
Lake southward) were referred to _S. c. stonei_ by Howell (_op.
cit._:16). Now that _S. c. saturatus_ has been recognized, these
specimens from southern Wisconsin would be expected to be referable to
_S. c. saturatus_. When these specimens were examined and compared (by
Hall and Kelson) with other specimens in the United States National
Museum the skulls were found to be much larger than in _S. c. cooperi_,
smaller than in _S. c. gossii_, and nearly the size of those of
_Synaptomys cooperi saturatus_, to which subspecies we refer the
specimens in question.

Howell (_op. cit._:16) referred a specimen from Cassopolis, Michigan, a
locality that might be presumed to fall within the range of the more
recently named _S. c. saturatus_, to _S. c. stonei_. Bole and Moulthrop
did not mention this specimen when they described and named _S. c.
saturatus_ (1942). Neither did Burt, but Cassopolis is within the
geographic range ascribed to _S. c. cooperi_ on his map (The Mammals of
Michigan, Univ. Michigan Press, p. 213, 1946). Examination (by Kelson
and Hall) of the specimen (41777 MCZ) reveals that it resembles _S. c.
cooperi_ in shortness of hind foot (18 mm.), shortness of tail (18
mm.), narrowness across zygomata (16 mm.), and grayish pelage. In the
long braincase, heavy rostrum, greater condylobasilar length, greater
lambdoidal breadth, long rostrum, and longer incisive foramina, it
agrees closely with specimens of _S. c. saturatus_, to which subspecies
we refer the specimen.

Necker and Hatfield (Bull. Chicago Acad. Sci., 6:54, 1941) referred
specimens from Rosiclaire, Illinois, to _S. c. gossii_. These specimens
were not mentioned by Bole and Moulthrop (_op. cit._) when they named
_S. c. saturatus_ although the specimens presumably would be referred
to the newly-named subspecies. We have examined the pertinent specimens
(Nos. 15781-15786 and 16049-16054 CNHM) and find that on the basis of
dark color, long and slender skull, heavy incisors, and small
cheek-teeth, they are referable to _S. c. saturatus_ Bole and
Moulthrop. None, however, has a tail so short as the type of _S. c.
saturatus_. For that matter, the average length of the tail of six near
topotypes (5 mi. W, 2-1/2 mi. S Monticello, Piatt County, Illinois,
Nos. 32037-32042 KU) exceeds that of the type (17.4 mm., range 12-20,
as compared to 14 mm. for the type).


    Synaptomys cooperi gossii (Coues)

    1877. _Arvicola (Synaptomys) gossii_ Coues, Monogr. N. Amer.
    Rodentia, p. 235 (published as a synonym of _Synaptomys cooperi_,
    but name stated to apply to Kansan specimens of which description
    and measurements are on p. 236), type from Neosho Falls, Woodson
    County, Kansas.

    1897. _Synaptomys cooperi gossii_, Rhoads, Proc. Acad. Nat. Sci.
    Philadelphia, 49:307, June.

In view of the taxonomic treatment accorded by Bole and Moulthrop (Sci.
Publs. Cleveland Mus. Nat. Hist, 5:149-151, September 11, 1942) to the
lemming mice of the species _Synaptomys cooperi_, as explained in the
preceding account, it has seemed desirable to examine Iowan specimens
of this species. Hall and Kelson examined the necessary material and
made the following conclusions. An adult male from Hillsboro (168453
USBS) has the lighter color and large skull of _S. c. gossii_ to which
Howell (N. Amer. Fauna, 50:19, August 5, 1927) referred the specimen.
The more western specimen from Knoxville, a young male (190358 USNM),
is almost exactly the same age as a male of _S. c. saturatus_ from
Bascom, Indiana (143701 USNM), and is but slightly older than a male
_S. c. gossii_ from Ft. Leavenworth, Kansas (91583 USBS). The upper
molariform tooth-row is the same length in the specimens from Kansas
and Iowa, but is longer in that from Indiana. The fact that the
specimen from Knoxville closely resembles the Kansan specimen in other
dimensions of the skull, which is larger than in the specimen from
Indiana, gives a basis for applying the name _Synaptomys cooperi
gossii_ to the specimen from Knoxville. This is the same name recently
used by Fichter and Hansen (Bull. Univ. Nebraska State Mus., 3(2):2,
September, 1947) for the Iowan specimens, although they seemingly
applied the name without being aware of Bole and Moulthrop's earlier
naming of _S. c. saturatus_ (Sci. Publs. Cleveland Mus. Nat. Hist.,
5:149, September 11, 1942).


    Synaptomys borealis sphagnicola Preble

    1899. _Synaptomys (Mictomys) sphagnicola_ Preble, Proc. Biol. Soc.
    Washington, 13:43, May 29, type from Fabyans, Coos County, New
    Hampshire.

    1927. _Synaptomys borealis sphagnicola_, A. B. Howell, N. Amer.
    Fauna, 50:30, August 5.

Howell (N. Amer. Fauna, 50:30-31, August 5, 1927) had only eight
specimens of this subspecies available when he revised the genus
_Synaptomys_. Of these eight (Maine: Mount Katahdin, 2; New Brunswick:
Near Bathurst, 1; New Hampshire: Fabyans, 1, the type; Quebec: St.
Rose, 4), only the type and one of the specimens from St. Rose are
adults. Concerning the others, Howell wrote (_op. cit._:31): "The
example from near Bathurst is not adult and has a damaged skull, so is
identified provisionally. All other specimens are too young for
positive diagnosis."

Since Howell's revision only one additional specimen has been reported.
Anderson (Ann. Rept. Provancher Soc. for 1939, p. 71, 1940) reported it
from Table Mountain, 3888 ft., Gaspé County, Quebec.

In the collection of the University of Kansas Museum of Natural History
there is still another specimen. It is an adult male topotype (No. 6483
KU, formerly No. 72 in the collection of Alfred E. Preble) obtained on
August 21, 1905, at Fabyans, New Hampshire. The measurements of this
specimen are as follows (measurements in parenthesis are those of the
type as given by Howell, _op. cit._): Total length, 135 (132); tail, 26
(24); hind foot, 22 (20); condylobasilar length, 25.1 (25.8); rostral
length, 6.5 (6.8); rostral breadth, 4.7 (4.9); interorbital breadth,
3.3 (2.8); zygomatic breadth, 15.4 (16.0); lambdoidal breadth, 12.1
(12.4); incisive foramina, 5.9 (5.7); height of skull, 9.1 (9.3).

Howell (_op. cit._:30) characterized _S. b. sphagnicola_ as: "Large and
high [skull] with narrow interorbital sharply ridged, the ridges of the
type being joined for a distance of 4 millimeters; interparietal narrow
and rectangular. The rostrum is long, tapering very little, and the
nasals, slightly constricted medially are quite narrow posteriorly. The
incisive foramina are long and wide." Howell further stated (_op.
cit._:30-31) that: "It is hard to predict what will be found to
constitute the most valuable cranial characters in distinguishing this
race from adult _medioximus_. The discernible differences now are in
the shape of the interparietals, rostral characters, and interorbital
differences that will probably not hold good when animals of the same
age are compared."

As can be seen from a comparison of the measurements given above for
the type and the topotype, some of the characteristics given by Howell
are not found in the topotype: The interorbital region is not narrow
(in fact it is wider than it ordinarily is in some other subspecies of
_Synaptomys borealis_) and the incisive foramina are not longer than in
other subspecies of _Synaptomys borealis_.

As far as present material permits us to judge, _Synaptomys borealis
sphagnicola_ is characterized, cranially, by: Skull large; interorbital
region sharply ridged (the ridges being joined for a distance of 4 mm.
in the type and of 4.5 mm. in the topotype); rostrum long, tapering
relatively little; nasals slightly constricted medially and unusually
narrow posteriorly; interparietal narrow and rectangular.


    Clethrionomys occidentalis caurinus (Bailey)

    1898. _Evotomys caurinus_ Bailey, Proc. Biol. Soc. Washington,
    12:21, January 27, type from Lund, east shore Malaspina Inlet,
    British Columbia.

    1935. _Clethrionomys gapperi caurinus_, Racey and Cowan, Rept.
    British Columbia Prov. Mus. for 1935, p. H 25.

Prior to 1935 _caurinus_ was considered to be a monotypic species. In
1935 Racey and Cowan (Rept. British Columbia Provincial Museum for
1935, pp. H 25-H 26) examined material from southwestern British
Columbia of _C. caurinus_, including a series of 24 specimens from Alta
Lake, and compared it with _Clethrionomys gapperi occidentalis_ and
_C. g. saturatus_. They found _caurinus_ to be distinct from _C. g.
saturatus_ but were "not convinced that _occidentalis_ and _caurinus_
both merit systematic recognition; should they prove to be
indistinguishable, as the little available material indicates,
_occidentalis_ will take precedence on grounds of priority. It is our
opinion that further study of the distribution of the genus in British
Columbia will lead to the recognition of _occidentalis_ as the form
inhabiting coast-line and _saturatus_ the interior of British Columbia"
p. H 26. In the face of these opinions Racey and Cowan nevertheless
recognized _caurinus_ under the name _Clethrionomys gapperi caurinus_
(Bailey).

In spite of the treatment by Racey and Cowan (_op. cit._) of
_occidentalis_ and _caurinus_ as subspecies of _C. gapperi_, later
authors arranged _occidentalis_ as a member of the "_californicus_"
group although they retained _caurinus_ in the _gapperi_ group. For
example, Davis (The Recent Mammals of Idaho, The Caxton Printers, pp.
307-308, 1939) assigned _C. caurinus_ to the _gapperi_ group, although
he regarded _C. caurinus_ as a species (not a subspecies). He regarded
also _C. occidentalis_ as a species (not a subspecies) but assigned
it to the _californicus_ group. Dalquest (Univ. Kansas Publ., Mus.
Nat. Hist., 2:344, April 9, 1948) considered _occidentalis_ to be
conspecific with _Clethrionomys californicus_ and wrote (_op.
cit._:101): "The _californicus_ group, I feel, contains only the races
of _Clethrionomys californicus_, while the _gapperi_ group contains _C.
gapperi_ and its races, including _caurinus_, and possible other
species." Dalquest gave no indication that he had examined any
specimens of _caurinus_.

When Dalquest (_op. cit._:344) arranged _occidentalis_ and
_californicus_ as subspecies of the same species, he used the name
combination _Clethrionomys californicus occidentalis_ because he
ignored, or was unaware of, the page priority of _occidentalis_ over
_californicus_. We regard the anterior position of _occidentalis_ as
nomenclatural priority and therefore employ _occidentalis_ rather than
_californicus_ as the specific name.

Differences between the _gapperi_ group and the _occidentalis_ group
include: postpalatal bridge (complete in both groups) truncate
posteriorly in the _gapperi_ group and with a median, posteriorly
directed, spine in the _occidentalis_ group (this character is not
evident in all specimens; some _gapperi_ have a spine, and some
_occidentalis_ have the spine much reduced); dentition of the
_occidentalis_ group is heavier; enamel pattern of M3 and m1 in
_occidentalis_ more simplified--the number of salient and re-entrant
angles tends to be reduced in adults of the _occidentalis_ group.

An examination of specimens of _caurinus_ (British Columbia: Mt.
Seymour, 2 KU; Lund, Malaspina Inlet, 2 USBS; and Inverness, mouth
Skeena River, 1 USBS), reveals that, in the presence of the median
postpalatal spine and in the characters of the molars, _caurinus_
agrees with the _occidentalis_ group.


    Clethrionomys occidentalis nivarius (Bailey)

    1897. _Evotomys nivarius_ Bailey, Proc. Biol. Soc. Washington,
    11:136, May 13, type from northwest slope of Mount Ellinor, 4000
    ft., Olympic Mts., Mason County, Washington.

The red-backed mouse of the Olympic Peninsula was originally accorded
specific rank. Currently it stands in the literature as a subspecies of
the wide-spread species _Clethrionomys gapperi_ because Dalquest (Univ.
Kansas Publ. Mus. Nat. Hist., 2:343, April 9, 1948) used the
name-combination _Clethrionomys gapperi nivarius_. Taylor and Shaw had
earlier (Occas. Papers Charles R. Conner Mus., 2:23, 1929) indicated
the same status by using the name _Evotomys gapperi nivarius_. Davis
(The Recent Mammals of Idaho, The Caxton Printers, Caldwell, Idaho, p.
306, April 5, 1939), however, indicated that the affinities of
_nivarius_ were with the _californicus_ [= _occidentalis_] group,
although he treated _nivarius_ as a distinct species. We have examined
two adult females (K. U. Nos. 10707 and 10708) of _nivarius_ from
Reflection Lake, 3800 ft., Jefferson County, Washington, and on the
basis of their thick, instead of thin, pterygoid processes concur with
Davis that the affinities of _nivarius_ are with the named kinds of
_Clethrionomys_ now arranged as subspecies of _Clethrionomys
occidentalis_, rather than with the kinds now arranged as subspecies of
_Clethrionomys gapperi_. Although we are aware that Dalquest (_op.
cit._:101-102) did not find actual intergradation between _nivarius_
and _Clethrionomys occidentalis occidentalis_--a ten-mile gap separated
their ranges--we prefer to use the name combination _Clethrionomys
occidentalis nivarius_. In doing so we recognize that intergradation
ultimately may be found between the two species _C. occidentalis_ and
_C. gapperi_; in that event the name _gapperi_ will apply as the name
of the species because it has priority over _occidentalis_.

The following named kinds of _Clethrionomys_ are considered to be
subspecies of _Clethrionomys occidentalis_:

    CLETHRIONOMYS OCCIDENTALS OCCIDENTALIS (Merriam).

        1890. _Evotomys occidentalis_ Merriam, N. Amer. Fauna, 4:25,
        October 8, type from Aberdeen, Chehalis County, Washington.

        1894. _Evotomys pygmaeus_ Rhoads, Proc. Acad. Nat. Sci.
        Philadelphia, p. 284, October 23, type from mouth of Nisqually
        River, Pierce County, Washington.

        1929. _Evotomys gapperi occidentalis_, Taylor and Shaw, Occas.
        Papers Charles R. Conner Mus., Washington State College, 2:23.

        1948. _Clethrionomys californicus occidentalis_, Dalquest,
        Univ. Kansas Publ., Mus. Nat. Hist., 2:344, April 9.

    CLETHRIONOMYS OCCIDENTALIS CALIFORNICUS (Merriam).

        1890. _Evotomys californicus_ Merriam, N. Amer. Fauna, 4:26,
        October 8, type from Eureka, Humboldt County, California.

    CLETHRIONOMYS OCCIDENTALIS CAURINUS (Bailey).

        1898. _Evotomys caurinus_ Bailey, Proc. Biol. Soc. Washington,
        12:21, January 27, type from Lund, east shore of Malaspina
        Inlet, British Columbia.

        1935. _Clethrionomys gapperi caurinus_, Racey and Cowan, Rept.
        British Columbia Prov. Mus. for 1935, p. H 25.

    CLETHRIONOMYS OCCIDENTALIS MAZAMA (Merriam).

        1897. _Evotomys mazama_ Merriam, Proc. Biol. Soc. Washington,
        11:71, April 21, type from Crater Lake, 7000 ft., Mount Mazama,
        Klamath County, Oregon.

        1936. _Clethrionomys californicus mazama_, Bailey, N. Amer.
        Fauna, 55:192, August 29.

    CLETHRIONOMYS OCCIDENTALIS NIVARIUS (Bailey).

        1897. _Evotomys nivarius_ Bailey, Proc. Biol. Soc. Washington,
        11:136, May 13, type from northwest slope of Mount Ellinor,
        4000 ft., Olympic Mts., Mason County, Washington.

    CLETHRIONOMYS OCCIDENTALIS OBSCURUS (Merriam).

        1897. _Evotomys obscurus_ Merriam, Proc. Biol. Soc. Washington,
        11:72, April 21, type from Prospect, 2600 ft., upper Rogue
        River Valley, Jackson County, Oregon.

        1933. _Clethrionomys mazama obscurus_, Grinnell, Univ.
        California Publ. Zool., 40:185, September 26.

        1936. _Clethrionomys californicus obscurus_, Bailey, N. Amer.
        Fauna, 55:192, August 29.


    Clethrionomys gapperi pallescens, new name

    1940. _Clethrionomys gapperi rufescens_ R. W. Smith, Amer. Midland
    Nat., 24:233, July, type from Wolfville, Kings County, Nova Scotia
    (_nec Arvicola rufescens_ de Selys Longchamps, 1836, from
    Longchamps-sur-Ger, Belgium).

The name _rufescens_, as applied by R. W. Smith (Amer. Midland Nat.,
24:233, July, 1940) to the red-backed mouse of Nova Scotia, seems to be
unavailable under the rules of the International Code of Zoological
Nomenclature, since it is a homonym of _Arvicola rufescens_ de Selys
Longchamps, 1836, which in turn is a synonym of _Clethrionomys
glareolus glareolus_ Schreber, 1780 (Ellerman and Morrison-Scott,
Checklist of Palaearctic and Indian Mammals, 1758 to 1946, p. 663,
November 19, 1951).


    Clethrionomys gapperi phaeus (Swarth)

    1911. _Evotomys phaeus_ Swarth, Univ. California Publ. Zool.,
    7:127, January 12, type from Marten Arm, Boca de Quadra, Alaska.

When Swarth (_loc. cit._) named the red-backed mouse of the mainland of
southern Alaska as a new subspecies, he characterized it as "Size
rather large. Differs from _E._ [= _Clethrionomys_] _wrangeli_, nearest
it geographically, in cranial characters and in much longer tail; from
_E. caurinus_, the species to the southward in British Columbia, in
larger size and longer tail." He remarked (_loc. cit._): "I had
supposed that the red-backed mouse occurring on the mainland coast of
this region would prove to be _E. wrangeli_, but the latter appears to
be purely an insular species. I have had no specimens of that race for
comparison, but the _Evotomys_ secured differ so widely from it in all
the essential peculiarities of the species as given in the published
descriptions that there seems little doubt of their belonging to a
different species. _Wrangeli_ has a short tail, less than twice as long
as the hind foot--in adults of _phaeus_ the tail is invariably more
than twice the length of the foot, frequently more than a third of the
entire length of the animal."

The external and cranial measurements of two subadults in the United
States National Museum (No. 217413 from Quadra Lake and No. 217415 from
Marten Arm, Boca de Quadra, taken in mid-February) and three old adults
from Fort [= Port] Simpson, British Columbia (Nos. 90263-90264, 90272
USBS), are almost the same as those given by Swarth in the original
description of _Clethrionomys phaeus_.

In cranial measurements, as well as in the structure of the palate and
last upper molar, _C. phaeus_ agrees with the _gapperi_ group (to which
it has been assigned by Davis, The Recent Mammals of Idaho, The Caxton
Printers, p. 306, April 5, 1939, and by Orr, Jour. Mamm., 26:69,
February 12, 1945) and differs from _Clethrionomys occidentalis
caurinus_ (which was assigned above to the _occidentalis_ group,
formerly the _californicus_ group).

Since the measurements of specimens examined by us, as well as those
recorded by Swarth (_op. cit._), fall within the range of those of the
species _Clethrionomys gapperi_, and since the differences between
_phaeus_ and _C. g. saturatus_ are of the kind and degree that separate
subspecies in _C. gapperi_ we employ the name combination
_Clethrionomys gapperi phaeus_ (Swarth). _C. g. saturatus_, as
understood by us, occurs to the southeast of _C. g. phaeus_ in the
Rocky Mountains of British Columbia, and in northeastern Washington,
northern Idaho and northwestern Montana.

    _Specimens examined._--Total, 23, distributed as follows: Alaska:
    Chickamin River (Behm Canal), 15 (MVZ); Boca de Quadra, 3 (MVZ);
    Marten Arm, Boca de Quadra, 1 (USNM); Quadra Lake, 1 (USNM).
    British Columbia: Fort [= Port] Simpson, 3 (USBS).


    Clethrionomys gapperi wrangeli (Bailey)

    1897. _Evotomys wrangeli_ Bailey, Proc. Biol. Soc. Washington,
    11:120, May 13, type from Wrangell, Wrangell Island, Alaska.

When Bailey (_loc. cit._) named the red-backed mouse from Wrangell
Island, Alaska, he characterized it as "A large, dull-colored species
entirely distinct from any known form," and remarked: "In no way does
_E._ [= _Clethrionomys_] _wrangeli_ show a close relationship to any
other American species. In size and relative proportions it comes
closest to _E. dawsoni_, from which it differs widely in coloration and
more widely in cranial characters. With the long-tailed species south
and east of its range there is no need of comparison."

Swarth (Univ. California Publ. Zool., 24:173, June 17, 1922) reported
that three specimens from Flood Glacier and 23 from Great Glacier,
British Columbia, and four from Sergief Island, at the mouth of the
Stikine River, Alaska, were: "All _E. wrangeli_, indistinguishable from
specimens at hand from Wrangell Island." Swarth further reported that,
although he found no intergradation between _Clethrionomys wrangeli_
from Flood Glacier and the nearly adjacent _Clethrionomys rutilus
dawsoni_, "the two species, however, resemble each other so closely in
form, and in some pelages in color also, that _wrangeli_ would seem to
be a coastal offshoot of _dawsoni_...."

Davis (The Recent Mammals of Idaho, The Caxton Printers, p. 306, April
5, 1939) and Orr (Jour. Mamm., 26:69, February 12, 1945) more recently
have shown that _Clethrionomys wrangeli_ is not a member of the
_rutilus_ group (to which _C. dawsoni_ belongs) but is a member of the
_gapperi_ group.

Our comparisons of a series of eight topotypes of _wrangeli_ (all in
the Biological Surveys Collection) with several subspecies of
_Clethrionomys gapperi_ (including _phaeus_, _saturatus_, _galei_,
_brevicaudus_, and others) reveal that the differences seen in
_wrangeli_ are of the kind and degree that serve to separate
subspecies. The red-backed mouse from Wrangell Island, then, should
stand as _Clethrionomys gapperi wrangeli_ (Bailey).

    _Specimens examined._--Total, 31, distributed as follows: Alaska:
    Wrangell, Wrangell Island, 27 (19 MVZ., 8 USBS); Sergief Island at
    mouth of Stikine River, 4 (MVZ).


    Clethrionomys gapperi solus, new subspecies

    _Type._--Male, adult, skin and skull, No. 74939, Biological Surveys
    Collection, United States National Museum; from Loring,
    Revillagigedo Island, Alaska; obtained on September 22, 1895, by C.
    P. Streator; original No. 4980.

    _Range._--Known only from two localities on Revillagigedo Island,
    Alaska.

    _Diagnosis._--A short-tailed, dark-colored member of the _gapperi_
    group. Dorsal stripe wide, between Chestnut and Bay (capitalized
    color terms after Ridgway: Color Standards and Color Nomenclature.
    Washington, D. C., 1912), with slight mixture of black-tipped
    hairs; sides and venter heavily washed with Ochraceous-Tawny. Skull
    flattened; rostrum proportionately short and wide; auditory bullae
    relatively uninflated.

    _Comparisons._--From topotypes of _Clethrionomys gapperi wrangeli_,
    _C. g. solus_ differs as follows: dorsal stripe wider and slightly
    brighter; sides brighter; venter more heavily washed with
    Ochraceous-Tawny (heavy wash in all 13 _C. g. solus_ examined; in
    _C. g. wrangeli_ no wash in 11, slight wash in 16, and heavy wash
    in only one); nasals, alveolar extent of upper cheek-teeth and
    incisive foramina shorter; skull shallower when measured with
    tympanic bullae included; rostrum averages slightly broader.

    From _C. g. phaeus_ of the adjacent mainland, _C. g. solus_ differs
    in: dorsal stripe slightly darker; ventral wash more prominent;
    tail shorter; skull smaller in all parts measured except that
    nasals are approximately the same length, auditory bullae notably
    smaller and teeth notably narrower.

    _Measurements._--External and cranial measurements of adults are
    shown in table 1.

    _Remarks._--Bailey (Proc. Biol. Soc. Washington, 11:120, May 13,
    1897) referred 17 specimens from Loring to his newly named species,
    _E. wrangeli_ [= _Clethrionomys gapperi wrangeli_] but based his
    description on specimens from Wrangell Island. He pointed out
    (_loc. cit._) that all of the specimens from Loring had the
    "bellies strongly washed with buffy-ochraceous, while more than
    half of those from Wrangell have whitish bellies."

    _Specimens examined._--Total, 13, all in the Biological Surveys
    Collection, U. S. National Museum, from the following localities:
    Alaska: Revillagigedo Island: Loring, 10; mouth of Fish Creek,
    Ketchikan, 3.


    Clethrionomys gapperi stikinensis, new subspecies

    _Type._--Male, adult, skin and skull, No. 30735, Museum of
    Vertebrate Zoology, University of California; from Stikine River at
    Great Glacier, British Columbia; obtained on August 13, 1919, by J.
    Dixon; original number 7691.

    _Range._--Known only from the lower Stikine River Valley of British
    Columbia and the Cleveland Peninsula of Alaska.

    _Diagnosis._--A medium-sized, dark-colored member of the _gapperi_
    group. Dorsal stripe wide, near Auburn with mixture of black-tipped
    hairs; sides and venter washed with Ochraceous-Tawny. Skull small;
    cheek-teeth narrow; auditory bullae relatively uninflated.

    _Comparisons._--From topotypes of _Clethrionomys gapperi wrangeli_,
    _C. g. stikinensis_ differs as follows: dorsal stripe slightly
    wider and brighter; sides slightly duller (lacking the olivaceous
    wash of _C. g. wrangeli_); all cranial measurements taken averaging
    smaller except height of skull, which is approximately the same;
    alveolar length of upper tooth-row and length of incisive foramina
    notably shorter; auditory bullae less inflated; cheek-teeth much
    narrower.

    From topotypes of _C. g. phaeus_, _C. g. stikinensis_ differs as
    follows: dorsal stripe and sides darker; auditory bullae less
    inflated; cheek-teeth narrower; skull smaller in most measurements
    taken (see table 1).

    From topotypes of _C. g. solus_, _C. g. stikinensis_ differs as
    follows: dorsal stripe lighter (more tawny underwash); ventral wash
    of buffy much paler (especially noticeable around mouth and on
    throat); zygomatic and lambdoidal breadths greater; skull deeper;
    auditory bullae more inflated; cheek-teeth slightly heavier.


    TABLE 1. _External and cranial measurements of Clethrionomys._

 N    |   |   |     |       |        |      |     |     |     |     |
 u    |   |   |     |       |        |      |     |     |     |     |
 m    |   |   |     |       |        |      |     |     |     |  L  |
 b    |   |   |     |       |        |      |     |     |     |  e  |
 e    |   |   |     |       |        |      |     |     |     |  n  |
 r  s |   |   |     |       |        |      |     |     |     |  g  |
    e |   |   |     |       |        |      |     |     |     |  t  |
 o  x |   |   |     |       |        |      |     |     |     |  h  |
 f    |   |   |     |   C   |        |      |     |     |     |     |
    o |   |   |     |   o   |        |      |     |     |     |  o  |
 i  r |   |   |     |   n   |        |      |     |     |     |  f  |
 n    |   |   |     |   d   |        |   L  |     | A   |  B  |     |
 d  s |   |   |     |   y   |    Z   |   a  |     | l   |  r  |  i  |
 i  p |   |   |     |   l   |    y   |   m  |  L  | v   |  e  |  n  |
 v  e |   |   |     |   o   |    g   |   b  |  e  | e  u|  a  |  c  |  H
 i  c |   |   |     |   b   |    o   |   d  |  n  | o  p|  d  |  i  |  e
 d  i |   |   |     |   a   |    m   |   o  |  g  | l  p|  t  |  s  |  i
 u  m | T |   |     |   s   |    a   |   i  |  t  | a  e|  h  |  i  |  g
 a  e | o |   |     |   i   |    t   |   d  |  h  | r  r|     |  v  |  h
 l  n | t |   |     |   l   |    i   |   a  |     |     |  o  |  e  |  t
 s    | a |   |  H  |   a   |    c   |   l  |  o  | l  t|  f  |     |
    m | l |   |  i  |   r   |        |      |  f  | e  o|     |  f  |  o
 o  e |   |   |  n  |       |    b   |   b  |     | n  o|  r  |  o  |  f
 f  a | l |   |  d  |   l   |    r   |   r  |  n  | g  t|  o  |  r  |
    s | e |   |     |   e   |    e   |   e  |  a  | t  h|  s  |  a  |  s
 e  u | n | T |  f  |   n   |    a   |   a  |  s  | h   |  t  |  m  |  k
 a  r | g | a |  o  |   g   |    d   |   d  |  a  |    r|  r  |  i  |  u
 c  e | t | i |  o  |   t   |    t   |   t  |  l  | o  o|  u  |  n  |  l
 h  d | h | l |  t  |   h   |    h   |   h  |  s  | f  w|  m  |  a  |  l

_Clethrionomys gapperi solus_, Loring

Male
type  |133|33 |20   | 22.3  | 12.5   |10.9  |6.8  |5.1  |3.4  |5.3  | 9.0
Male
5 av. |131|34 |20   | 22    | 12.7   |10.8  |6.8  |5.3  |3.5  |5.1  | 9.1
  min.|128|33 |19   | 21.8  | 12.5   |10.5  |6.7  |5.1  |3.3  |5.0  | 8.9
  max.|133|36 |20   | 22.3  | 13.0   |11.2  |7.1  |5.5  |3.6  |5.3  | 9.5
Female
5 av. |128|34 |19   | 21.3  | 12.5   |10.5  |6.5  |5.4  |3.5  |4.9  | 9.2
  min.|124|31 |19   | 20.9  | 12.3   |10.3  |6.0  |5.2  |3.3  |4.8  | 8.9
  max.|140|36 |20   | 21.7  | 12.7   |10.7  |7.0  |5.6  |3.6  |5.0  | 9.5

_Clethrionomys gapperi stikinensis_, Stikine River at Great Glacier

Male
type  |145|39 |20   | 23.2  | 13.9   |11.4  |7.3  |5.0  |3.1  |5.5  | 9.5
Male
4 av. |136|35 |20   | 22.2  | 13.0   |11.1  |6.8  |5.2  |3.4  |5.2  | 9.4
  min.|132|33 |19   | 21.5  | 12.3   |10.7  |6.5  |5.0  |3.1  |5.1  | 9.1
  max.|145|39 |20   | 23.2  | 13.9   |11.4  |7.3  |5.6  |3.5  |5.5  | 9.7
Female
7 av. |134|33 |19   | 21.8  | 12.7^6*|10.9  |7.0  |5.4  |3.4  |5.1  | 9.5
  min.|125|30 |19   | 21.5  | 12.5   |10.5  |6.7  |5.3  |3.2  |5.0  | 9.2
  max.|147|35 |20   | 22.2  | 12.9   |11.   |7.1  |5.6  |3.7  |5.3  | 9.8

_Clethrionomys gapperi wrangeli_, Wrangell

Male
9 av. |139|36 |19   | 23.4^8| 13.3  |11.4^8 |7.3  | .6  | .6  | .6  | 9.6^8
  min.|130|31 |18   | 22.9  | 13.0  |10.9   |7.1  |5.5  |3.3  |5.4  | 9.2
  max.|151|43 |20   | 23.9  | 13.7  |11.8   |7.6  |5.8  |4.0  |5.8  |10.1
Female
16 av.|134|34 |18^15| 23.2  | 13.3  |11.2^13|7.3  |5.8  |3.5  |5.5  | 9.4
  min.|123|28 |17   | 22.4  | 12.6  |10.7   |6.9  |5.5  |3.2  |5.2  | 9.0
  max.|156|45 |20   | 24.1  | 14.1  |11.8   |8.0  |6.1  |3.7  |5.9  | 9.7

_Clethrionomys gapperi phaeus_, Chickamin River

Male
5 av. |148|47 |20   | 23.0^4| 13.7^4|11.3^4 |7.5^4|5.3^4|3.5^4|5.3^4| 9.7^3
  min.|138|38 |20   | 22.3  | 13.0  |11.1   |7.1  |5.3  |3.4  |4.9  | 9.3
  max.|159|51 |21   | 23.8  | 14.6  |11.8   |7.7  |5.6  |3.8  |5.6  |10.0
Female
4 av. |153|49 |20   | 23.1^3| 13.4  |11.2^3 |7.6^3|5.2  |3.7  |5.3  | 9.6^3
  min.|140|44 |20   | 22.4  | 12.8  |10.8   |7.3  |5.0  |3.4  |5.1  | 9.2
  max.|164|56 |20   | 24.2  | 13.6  |11.4   |7.7  |5.3  |3.9  |5.5  | 9.8

      *Superior numbers denote the number of individuals averaged.


_Measurements_.--External and cranial measurements of adults are given
in table 1.

_Remarks_.--Morphologically _C. g. stikinensis_ shows greater
resemblance to _C. g. solus_ of Revillagigedo Island, than to the
geographically adjacent subspecies _C. g. wrangeli_ and _C. g. phaeus_.
Possibly the original stock of _C. g. solus_ was rafted to
Revillagigedo Island from the Cleveland Peninsula.

    _Specimens examined_.--Total, 29, all in the Museum of Vertebrate
    Zoology, University of California, distributed as follows: British
    Columbia: Stikine River at Great Glacier, 22; Stikine River at
    Flood Glacier, 3. Alaska: Bradfield Canal, 1; Helm Bay, 2.


    Pitymys pinetorum scalopsoides (Audubon and Bachman)

    1841. _Arvicola scalopsoides_ Audubon and Bachman, Proc. Acad. Nat.
    Sci. Philadelphia, 1:97, type from Long Island, New York.

    1912. _Pitymys pinetorum scalopsoides_ Miller, U. S. Nat. Mus.
    Bull., 79:229, December 31.

Hanson (Trans. Wisconsin Acad. Sci., Arts, and Letters, 36:124, 1944)
reported two pine mice from near Prairie du Sac, in Westpoint Township,
Columbia County, Wisconsin, as _Pitymys pinetorum scalopsoides_ but
cast doubt upon their subspecific identity. He also reported pine mice
from Blue Mounds, Dane County, Wisconsin. We have examined these
specimens (Westpoint, Columbia County, 2--No. 544, skin only, UWDEZ,
and No. 521, skin only, H. C. Hanson's private collection; Westpoint,
Dane County, 1, No. 11620, UWZM; Vermont, Dane County, 2, Nos. 11674
and 11694, UWZM) and have compared them with topotypes of _P. p.
schmidti_, and with specimens of _P. p. nemoralis_ and _P. p.
scalopsoides_. The specimens from Columbia and Dane counties differ
from _P. p. schmidti_ in the greater zygomatic breadth, and lesser
height of skull. They differ from _P. p. nemoralis_ of comparable age
in shorter tooth-row and generally smaller skull. The interorbital
region, however, is wider. In all of the features mentioned above, the
specimens in question agree with _Pitymys pinetorum scalopsoides_, to
which subspecies they are here referred.


    Microtus pennsylvanicus aztecus (Allen)

    1893. _Arvicola (Mynomes) aztecus_ Allen, Bull. Amer. Mus. Nat.
    Hist., 5:73, April 28, type from Aztec, 5900 ft., San Juan County,
    New Mexico.

Allen (_loc. cit._) described this species on the basis of two
specimens from Aztec, New Mexico, and three from La Plata, New Mexico.
He characterized it as "Size large; pelage very full and soft; tail
short; skull very narrow.

"Above grayish brown with a tinge of pale buff; fur blackish plumbeous
beneath the surface, tipped with pale yellowish brown, and varied with
longer, projecting, black-tipped hairs; below grayish white, the fur
plumbeous beneath the surface and tipped with white, giving a whitish
gray effect. Feet dusky; tail dusky brown above, dull white below."

Allen identified as this species "a large _Arvicola_ from Estes Park,
Colorado, which I have before been unable to allocate. I am unable to
find that it differs in any particular from the specimens from New
Mexico." He pointed out also (_op. cit._:73-74) that "The type and only
positively identified specimen of Baird's _Arvicola modesta_ [=
_Microtus pennsylvanicus modestus_ (Baird)] from Sawatche Pass,
Colorado, is a very young specimen in poor condition. An examination of
a series of adult and young examples from the type locality will be
necessary in order to determine its relationships to _A. alticolus_ [=
_Microtus longicaudus alticolus_ (Merriam)] and _A. aztecus_."

Bailey, in his revision of the American voles of the genus _Microtus_
(N. Amer. Fauna, 17:20), showed _Arvicola modesta_ Baird to be a
subspecies of _Microtus pennsylvanicus_ but retained _Microtus aztecus_
(Allen) as a distinct species. In describing _M. aztecus_ he wrote "the
size similar to _M. pennsylvanicus_, but with shorter tail and larger
hindfoot; skull long; braincase narrow; interparietal long ..." and
remarked that "_Microtus aztecus_ belongs to the _pennsylvanicus_
group. Externally it is not very different from _modestus_, but none of
the specimens show any signs of intergradation; and the skull
characters are so well marked that there seems no doubt of its full
specific rank."

Subsequent to the publication of Allen's (_op. cit._) account and
Bailey's account (_op. cit._), additional material was collected that
helps to clarify the relationships of _Microtus aztecus_. A comparison
of six adult topotypes of _Microtus aztecus_ with a series of nine
adults of _M. p. modestus_ from 1 mi. S, 2 mi. E Eagle Nest, 8100 ft.,
Colfax County, New Mexico, with three adults from 1-1/2 mi. E Manassa,
Conejos County, Colorado, and with four adults from Saguache County,
Colorado (all in KU), reveals that the supposed "well marked" external
and cranial differences between the two forms are not nearly so evident
as was indicated by Bailey.

The cranial differences that exist between these two forms (narrower
nasals, slightly longer interparietal, slightly longer and narrower
skull in _aztecus_) are evident only as averages. Although
geographically intermediate specimens are lacking, the morphological
differences between the two kinds of animals are of the degree and kind
that separate subspecies, rather than species. We therefore judge _M.
aztecus_ (Allen) to be only subspecifically distinct from _M.
pennsylvanicus modestus_ and employ the name _Microtus pennsylvanicus
aztecus_.


    Microtus pennsylvanicus funebris (Dale)

    1940. _Microtus pennsylvanicus funebris_ Dale, Jour. Mamm., 21:338,
    August 14, type from Coldstream, 1450 ft., 3-1/2 mi. SE Vernon,
    British Columbia.

Taylor and Shaw (Occas. Papers Charles R. Conner Mus., State College
Washington, 2:24, December, 1929) list under _Microtus nanus_ [=
_montanus_] _canescens_ material from Calispell Peak, Washington.
Probably the basis for this record is a specimen in the Biological
Surveys collection (adult male, 236474) taken on May 9, 1921, by G. G.
Cantwell, and labelled as Calispell Peak, 9 mi. W Locke, 3500 ft., Pend
Oreille County. An examination (by Hall and Kelson) of the specimen
discloses that it is of the species _Microtus pennsylvanicus_, and that
it falls within the geographic range ascribed to the subspecies
_Microtus pennsylvanicus funebris_ by Dalquest (Univ. Kansas Publ.,
Mus. Nat. Hist., 2:346, April 9, 1948).


    Microtus oeconomus amakensis (Murie)

    1930. _Microtus amakensis_ Murie, Jour. Mamm., 11:74, February 11,
    type from Amak Island, Bering Sea, Alaska.

When Murie (Jour. Mamm., 11:75, February 11, 1930) named the meadow
mouse from Amak Island, Alaska, as _amakensis_, he arranged it as a
separate species. One of us (Hall) and K. R. Kelson examined the type
and topotypes of _amakensis_ in the Biological Surveys collection in
the U. S. National Museum and compared them with series of _Microtus
oeconomus operarius_, _M. o. sitkensis_, _M. o. elymocetes_, _M. o.
yakutatensis_, and _M. o. kadiacensis_. Among the specimens examined of
the latter subspecies were 17 from Izambek Bay, Kodiak Peninsula, on
the mainland opposite Amak Island, the type locality of _amakensis_.
The characters given by Murie (_op. cit._) serve to separate
_amakensis_ from closely related neighboring kinds of meadow mice, but
are of the degree and kind that, in this group of meadow mice, separate
subspecies rather than species. Although actual intergrades are
lacking, the animals from Amak Island are considered to be only
subspecifically distinct and to belong to the _oeconomus_ complex. The
name _Microtus oeconomus amakensis_ is applied to them.


    Microtus longicaudus mordax (Merriam)

    1891. _Arvicola_ (_Mynomes_) _mordax_ Merriam, N. Amer. Fauna,
    5:61, July 30, type from Sawtooth (= Alturas) Lake, 7200 ft., east
    base of Sawtooth Mountains, Blaine County, Idaho.

    1938. _Microtus longicaudus mordax_, Goldman, Jour. Mamm., 19:491,
    November 14.

Dalquest (Univ. Kansas Publ., Mus. Nat. Hist., 2:353, April 9, 1948)
assigned all the meadow mice of the species _Microtus longicaudus_ from
approximately the eastern half of Washington State to _Microtus
longicaudus halli_ Hayman and Holt and, in doing so, excluded the
subspecies _Microtus longicaudus mordax_ from that state. This
assignment of specimens in Washington had the effect of separating the
geographic range of _M. l. mordax_ into two parts. One part was in
south-central British Columbia and the other part was mainly in the
Rocky Mountain region of the United States. Hall and Kelson examined
specimens in the Biological Surveys collection in the U. S. National
Museum in an attempt to determine more precisely the ranges of the
subspecies in southern Canada, Washington, and Idaho.

_Microtus longicaudus angustus_ [= _M. l. halli_] was described by one
of us (Hall, Univ. California Publ. Zool., 37:13, April 10, 1931) as
differing from _mordax_ in narrower braincase, higher skull near the
anterior end of the frontals, darker coloration, and seemingly smaller
size. After examining the material in the U. S. National Museum no
reason is seen at the present time to amend this characterization,
except to add that some specimens of _M. l. mordax_ are as dark as
seasonably comparable specimens of _M. l. halli_.

Examination of specimens of _Microtus longicaudus_ from Washington east
of the Cascade Range (those from the Blue Mountain area excepted)
discloses that the skulls do not differ essentially from those of
topotypes of _M. l. mordax_, but do differ, as outlined above, from
near-topotypes of _M. l. halli_. There is considerable variation in
color among the Washington-taken specimens of _Microtus longicaudus_.
Animals from the eastern flanks of the Cascades average darker than
those taken, north of the Snake River, still farther east in
Washington. Possibly Dalquest (_op. cit._) relied mainly upon this
darker color in assigning the specimens from eastern Washington to _M.
l. halli_. Relying principally upon cranial characters, we conclude
that most of the specimens are better referred to _M. l. mordax_ and
that _M. l. halli_ is restricted, in Washington, to the Blue Mountains.

    _Specimens examined of Microtus longicaudus mordax._--Total, 74,
    all in the Biological Surveys Collection, distributed as follows:
    Washington: _Okanogan_ _County_: mouth of Holmar Creek, W Fork
    Paysaten River, 4700 ft., 1; Conconully, 3; Twisp, 1; Omak Lake,
    1200 ft., 3. _Stevens County_: 5 mi. N Colville, 1. _Pend Oreille
    County_: 9 mi. N Metalina, 2600 ft., 1; Sullivan Lake, 3000 ft., 3.
    _Chelan County_: Sethekin, 1079 ft., 3; head of Lake Chelan, 900
    ft., 12; Hart Lake, Railroad Creek, 3900 ft., 1; Entiat, 20 mi from
    mouth of Entiat River, 1680 ft., 13; Wenatchee, 4. _Douglas
    County_: Waterville, 1. _Jefferson County_: Cleveland, 2. _Kittitas
    County_: 2 mi. S Blewett Pass, 3000 ft., 6: Ellensburg, 1500 ft.,
    4. _Whitman County_: Colfax, 2. _Yakima County_: McAllister
    Meadows, Tieton River, 3000 ft., 3; Gotchen Cr., 5500 ft., near
    Sava Spring, Mt. Adams, 2. _Klickitat County_: 8 mi. S Glenwood,
    base Mt. Adams, 2. _Asotin County_: Anatone, 3300 ft., 4; Bly, 1000
    ft., 2.


    Microtus miurus muriei (Nelson)

    1931. _Microtus muriei_ Nelson, Jour. Mamm., 12:311, August 24,
    type from Kutuk River (tributary of Alatna River), Endicott Mts.,
    Alaska.

Rausch (Jour. Washington Acad. Sci., 40:135, April 21, 1950) proposed
the name _Microtus miurus paneaki_, with type locality at Tolugak Lake
(lat. 68° 24' N, long. 152° 10' W), Brooks Range, Alaska, for a meadow
mouse of the subgenus _Stenocranius_. This place is only approximately
forty miles east and north of the type locality of the earlier named
_Microtus muriei_, also a member of the subgenus _Stenocranius_. 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° 12',
152° 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
American mouse is specifically distinct from any of the previously
named Asiatic species--at this writing we lack material to decide this
question--the named kinds from the mainland of the New World may stand
as follows:

    MICROTUS MIURUS ANDERSONI Rand.

        1945. _Microtus andersoni_ Rand, Bull. Nat. Mus. Canada, 99:42,
        prior to June 20, type from near headwaters of Little Keel
        River, 5500 ft., 82 mi. W Mackenzie River on Canol Road,
        Mackenzie.

    MICROTUS MIURUS CANTATOR Anderson.

        1947. _Microtus cantator_ Anderson, Bull. Nat. Mus. Canada,
        102:161, January 24, type from mountain top near Tepee Lake,
        61° 35' N, 140° 22' W, N slope Elias Range, Yukon Terr.

    MICROTUS MIURUS MIURUS Osgood.

        1901. _Microtus miurus_ Osgood, N. Amer. Fauna, 21:64,
        September 26, type from head of Bear Creek, in mts. near Hope
        City, Turnagain Arm, Cook Inlet, Alaska.

    MICROTUS MIURUS MURIEI Nelson.

        1931. _Microtus muriei_ Nelson, Jour. Mamm., 12:311, August 24,
        type from Kutuk River (tributary of Alatna River), Endicott
        Mts., Alaska.

        1950. _Microtus miurus paneaki_ Rausch, Jour. Washington Acad.
        Sci., 40:135, April 21, type from Tolugak Lake (lat. 68° 24' N,
        long. 152° 10'), Brooks Range, Alaska.

    MICROTUS MIURUS OREAS Osgood.

        1907. _Microtus miurus oreas_ Osgood, Proc. Biol. Soc.
        Washington, 20:61, April 18, type from Toklat River, Alaskan
        Range, Alaska.


    _Transmitted July 8, 1952._