_Microtus pennsylvanicus drummondii_ Hollister, Canadian Alp. Jour., Special Number, p. 23, February 17, 1913.
_Specimens examined._--Total 93, as follows: _Yukon Territory_: McIntyre Creek, 2250 ft., 3 mi. NW Whitehorse, 26; W side Lewes River, 2150 ft., 2 mi. S Whitehorse, 4; 5 mi. W Teslin River, 2400 ft., 16 mi. S and 53 mi. E Whitehorse, 7; E side Teslin River, 2300 ft., 16 mi. S and 59 mi. E Whitehorse, 1. _British Columbia_: 1 mi. NW jct.
Irons Creek and Liard River, 8; Hot Springs, 3 mi. WNW jct. Trout River and Liard River, 3; N side Liard River, mi. W jct. Liard River and Trout River, 1; mi. S jct. Trout River and Liard River, 13; S side Toad River, 10 mi. S and 21 mi. E Muncho Lake, 2; Summit Pa.s.s, 4200 ft., 10 mi. S and 70 mi. W Fort Nelson, 2; E side Minaker River, 1 mi. W Trutch, 19; Beatton River, 115 mi. S Fort Nelson, 1; 5 mi. W and 3 mi. N Fort St. John, 2. _Alberta_: a.s.sineau River, 1920 ft., 10 mi. E and 1 mi. N Kinuso, 4.
_Remarks._--Adults among the specimens listed above vary but little; one female from a.s.sineau River in Alberta is notably more reddish than others taken elsewhere.
Average and extreme measurements of nine adults of both s.e.xes of _M.
p. drummondii_ from E side Minaker River, 1 mi. W Trutch, British Columbia, are as follows: Total length, 157 (148-165); length of tail, 42 (37-46); condylobasal length, 25.1 (24.7-26.0); basal length, 24.2 (23.4-25.0); length of nasals, 6.8 (6.4-7.2); zygomatic breadth, 14.4 (13.9-14.7); breadth across auditory bullae, 12.4 (12.0-12.7); alveolar length of upper molariform tooth-row, 6.1 (6.0-6.2); Nine adults of both s.e.xes from McIntyre Creek, 2250 ft., 3 miles northwest of Whitehorse, Yukon Territory, have the following measurements: 153 (147-168); 40 (33-47); 24.9 (24.2-25.5); 24.0 (23.6-24.6); 6.6 (6.2-7.2); 14.4 (13.9-15.1); 12.1 (11.7-12.5); 6.1 (6.0-6.2).
Microtus _cf._ cantator Anderson
Yukon Singing Mouse
_Microtus cantator_ Anderson, Nat. Mus. Canada, Bull. No. 102, Biol. Ser. No. 31:161, [for 1946], January 24, 1947. (Type "taken in tundra-slide above timber-line on mountain top near Tepee Lake on north slope of St. Elias Range," Yukon Territory, Canada.)
_Specimen examined._--One from _Alaska_: Fish Creek, 3400 ft., 5 mi. N and 1 mi. E Paxson.
_Remarks._--The single adult male, obtained by Alcorn, has been compared by Dr. Henry W. Setzer with specimens of _Microtus muriei_ Nelson, _M. miurus miurus_ Osgood, and _M. m. oreas_ Osgood in the United States National Museum. He reports that the specimen is related most closely to _M. miurus_ but exhibits characters by which it is, at least, subspecifically distinct from these two forms of this species.
Three specimens of _M. andersoni_ Rand and one of _M. cantator_ Anderson, borrowed from the National Museum of Canada are less mature than the specimen in question. Even so, the male from Fish Creek is less gray than _M. andersoni_ and as seen from measurements of the type, an adult male (Rand, 1945:42), is larger with longer tail and has a shorter and narrower skull and is judged to be taxonomically separable. _M. cantator_ was named from two specimens; both the paratype (seen by me) and seemingly the type are too young to show clearly subspecific characters. Alcorn"s specimen is tentatively referred to _M. cantator_ until some adult topotypes can be obtained.
Measurements of the male, No. 21539, from Fish Creek, are: Total length, 152; length of tail, 30; hind foot, 22; condylobasal length, 28.0; basal length, 26.6; length of nasals, 7.1; zygomatic breadth, 13.8; breadth across auditory bullae, 11.5; least interorbital breadth, 3.3; alveolar length of upper molariform tooth-row, 6.2.
Alcorn took this specimen in an area above timberline where a low growth of willow was the dominant vegetation. Traps were set where he had seen a mouse go into a small burrow. The next morning, August 18, 1947, he found this specimen and two _Microtus oeconomus macfarlani_ in his traps.
Microtines of the subgenus _Stenocranius_ from continental areas of Alaska and Northwestern Canada are represented in collections by a few specimens from widely separated localities. Lacking material from intermediate localities, describers have given specific recognition to several of these isolated populations. Future collecting will be necessary to disclose whether the North American mice of this subgenus belong to one or to more than one species and may disclose whether or not there has been more than one invasion of the North American continent by members of this Asiatic group.
Microtus longicaudus vellerosus J. A. Allen
Long-tailed Meadow Mouse
_Microtus vellerosus_ J. A. Allen, Bull. Amer. Mus. Nat. Hist., 12:7, March 4, 1899. (Type from upper Liard River, British Columbia, Canada.)
_Microtus longicaudus vellerosus_ Anderson and Rand, Canadian Field-Nat., 58:20, April 1, 1944.
_Specimens examined._--Total 127, as follows: _Alaska_: N side Salcha River, 600 ft., 25 mi. S and 20 mi. E Fairbanks, 1. _Yukon Territory_: 6 mi. SW Kluane, 2550 ft., 2; McIntyre Creek, 2250 ft., 3 mi. NW Whitehorse, 10; mi. W Whitehorse, 1; SW end Dezadeash Lake, 18; 1 mi. S and 3 mi. E Dalton Post, 2500 ft., 24. _British Columbia_: Stonehouse Creek, 5 mi. W jct. Stonehouse Creek and Kelsall River, 20; Hot Springs, 3 mi. WNW jct. Trout River and Liard River, 4; mi.
S jct. Trout River and Liard River, 15; S side Toad River, 10 mi. S and 21 mi. E Muncho Lake, 27; SE end Muncho Lake, 4; Summit Pa.s.s, 4500 ft., 10 mi. S and 70 mi. W Fort Nelson, 1.
_Remarks._--Specimens from 1 miles south and 3 miles east of Dalton Post and from Dezadeash Lake in Yukon Territory and from Stonehouse Creek in British Columbia are referred to _M. l. vellerosus_ although in color of upper parts they show close relationship with _M. l.
littoralis_. These specimens are less gray and more brown than specimens more typical of _M. l. vellerosus_ from the Liard River area.
Alcorn found the long-tailed meadow mouse in widely separated areas.
Most specimens were obtained in gra.s.sy situations near water or on moist ground. The single male from Summit Pa.s.s in British Columbia was taken above timberline.
Microtus longicaudus littoralis Swarth
Long-tailed Meadow Mouse
_Microtus mordax littoralis_ Swarth, Proc. Biol. Soc. Washington, 46:209, October 26, 1933. (Type from Shakan, Prince of Wales Island, Alaska.)
_Microtus longicaudus littoralis_ Goldman, Jour. Mamm., 19:491, November 14, 1938.
_Specimens examined._--Total 29, as follows: _Alaska_: E side Chilkat River, 100 ft., 9 mi. W and 4 mi. N Haines, 9; 1 mi. S Haines, 5 ft., 20.
_Remarks._--In comparison with the series of _M. l. vellerosus_ from the Liard River area, the long-tailed meadow mice from near Haines are more reddish brown, have a longer tail, and have a smaller skull with smaller auditory bullae. This subspecies is restricted to the coastal area, and as noted under the account of _M. l. vellerosus_, intergradation between these two forms occurs a relatively short distance inland.
Microtus oeconomus macfarlani Merriam
Tundra Mouse
_Microtus macfarlani_ Merriam, Proc. Washington Acad. Sci., 2:24, March 14, 1900. (Type from Fort Anderson, Anderson River, Mackenzie district, Northwest Territories, Canada.)
_Microtus oec[onomus] macfarlani_ Zimmerman, Archiv f. Naturgesch., 11:187, September 12, 1942.
_Specimens examined._--Total 70, as follows: _Alaska_: Circle, 664 ft., 1; Chatanika River, 700 ft., 14 mi. E and 25 mi. N Fairbanks, 13; Twelve Mile Summit, 3225 ft., Steese Highway, 6; 1 mi. SW Fairbanks, 440 ft., 3; N side Salcha River, 600 ft., 25 mi. S and 20 mi. E Fairbanks, 28; Yerrick Creek, 21 mi. W and 4 mi. N Tok Junction, 9; Fish Creek, 3400 ft., 5 mi. N and 1 mi. E Paxson, 3; Glenn Highway, 6 mi. WSW Snowshoe Lake, 1. _Yukon Territory_: Jct. Grafe and Edith Creeks, 1; 6 mi. SW Kluane, 2550 ft., 2; SW end Dezadeash Lake, 1.
_British Columbia_: Stonehouse Creek, 5 mi. W jct. Stonehouse Creek and Kelsall River, 2.
_Remarks._--Alcorn found the tundra mouse in many of the localities at which he trapped in east-central Alaska. Specimens were taken above timberline, along roads, in gra.s.sy areas which had been cleared of timber, and in low vegetation bordering streams. On August 17 at Fish Creek, 5 miles north and 1 mile east of Paxson, Alaska, Alcorn obtained one of these mice in a tree in the daytime. Immature specimens taken at Stonehouse Creek are, to my knowledge, the first records for this species in British Columbia.
Mus musculus Linnaeus
House Mouse
_[Mus] musculus_ Linnaeus, Syst. Nat., ed. 10, 1:62, 1758.
(Type from Upsala, Sweden.)
_Specimens examined._--Total 6, as follows: _Alaska_: 1 mi. NE Anchorage, 100 ft., 2. _Yukon Territory_: McIntyre Creek, 2259 ft., 3 mi. NW Whitehorse, 2; 2 mi. NNW Whitehorse, 2100 ft., 1. _Alberta_: a.s.sineau River, 1920 ft., 10 mi. E and 1 mi. N Kinuso, 1.
_Remarks._--Alcorn took house mice in and near areas inhabited by man.
One mouse was taken near Whitehorse on July 10 under a building which had not been occupied for one year. Another was taken at the Whitehorse city dump. Near Kinuso, one specimen was obtained at the site of an old sawmill.
Zapus hudsonius hudsonius (Zimmermann)
Meadow Jumping Mouse
_Dipus hudsonius_ Zimmermann, Geogr. Gesch., 2:358, 1780.
(Type from Hudson Bay, Canada.)
_Zapus hudsonius_ Coues, Bull. U. S. Geol. and Geogr. Surv. Terr., ser. 2, 1:253, January 8, 1876.
_Specimens examined._--Total 8, as follows: _British Columbia_: 1 mi.
NW jct. Irons Creek and Liard River, 3; Hot Springs, 3 mi. WNW jct.
Trout River and Liard River, 1; E side Minaker River, 1 mi. W Trutch, 1; 5 mi. W and 3 mi. N Fort St. John, 1. _Alberta_: a.s.sineau River, 1920 ft., 10 mi. E and 1 mi. N Kinuso, 1.