_Remarks._--Specimens from one mile northeast of Anchorage show little tendency toward _C. r. orca_ from the Prince William Sound area (see Orr, 1945:73). One specimen from this locality is slightly darker than the others. Red-backed mice were numerous in most localities where Alcorn trapped. A number of specimens were taken adjacent to and within abandoned road camps, where second growth vegetation was rank. As in the case of _C. gapperi_, he found _C. rutilus_ in varied habitats. Clethrionomys gapperi athabascae (Preble) Red-backed Mouse _Evotomys gapperi athabascae_ Preble, N. Amer. Fauna, 27:178, October 26, 1908. (Type from Fort Smith, Slave Lake, Mackenzie District, Northwest Territories, Canada.) _Clethrionomys gapperi athabascae_ Harper, Jour. Mamm., 13:28, February 9, 1932. _Specimens examined._--Total 14, as follows: _British Columbia_: N side Muska River, 1200 ft., 4 mi. W Fort Nelson, 1; E side Minaker River, 1 mi. W Trutch, 3; 5 mi. W and 3 mi. N Fort St. John, 4. _Alberta_: Assineau River, 1920 ft., 10 mi. E and 1 mi. N Kinuso, 6. _Remarks._--These red-backed mice were taken in various habitats: grassy areas in aspen and poplar forest, heavy spruce forest with no undergrowth excepting lichens and moss, thick underbrush in river flood plain, and at the site of an old sawmill. The northwestern distribution of this species along the Alaska Highway as found by Alcorn is approximately the same as that found by Rand (1944:44). Ondatra zibethicus spatulatus (Osgood) Muskrat _Fiber spatulatus_ Osgood, N. Amer. Fauna, 19:36, October 6, 1900. (Type from Lake Marsh, Yukon, Canada.) _Ondatra zibethica spatulata_ Miller, N. Amer. Land Mamm. 1911, p. 231, December 31, 1912. _Specimens examined._--Total 2, as follows: _Alaska_: N side Salcha River, 600 ft., 25 mi. S and 20 mi. E Fairbanks, 1; E side Deadman Lake, 1800 ft., 15 mi. NE Northway, 1. _Remarks._--One muskrat was shot in an old beaver pond on the north side of the Salcha River. A skull from a carcass, that had been left by a trapper the previous winter, was obtained at Deadman Lake. Phenacomys intermedius mackenzii Preble Lemming Mouse _Phenacomys mackenzii_ Preble, Proc. Biol. Soc. Washington, 15:182, August 6, 1902. (Type from Fort Smith, Slave River, Mackenzie, Canada.) _Phenacomys intermedius mackenzii_ Crowe, Bull. Amer. Mus. Nat. Hist, 80:403, February 4, 1943. _Specimen examined._--One from _Yukon Territory_: SE end Dezadeash Lake. _Remarks._--A subadult taken only a few miles from the Alaskan border in Yukon Territory constitutes an extension of the known range of this species to the northwest. The mouse is evidently rare or irregular in its distribution since Alcorn did considerable trapping in the area from which only one was taken. Microtus pennsylvanicus Pennsylvania Meadow Mouse