_Type._--Obtained on the Columbia River (probably on or near Sauvie Island, Multnomah County, Oregon); type in Philadelphia Academy of Natural Sciences. _Racial characters._--Size large; skull narrow in interorbital region. _Measurements._--Eight males and 5 females from Clark and Pacific counties, southwestern Washington, average, respectively: total length 208.0, 208.4; length of tail 65.7, 66.0; hind foot 26.5, 25.4; ear 15.0, 14.6; weight 80.8, 76.7 grams. Thirteen males and 9 females from Seattle average, respectively: 211.8, 209.0; 71.2, 68.6; 25.7, 26.0; 15.8, 15.4. _Distribution._--The lowlands of western Washington from Bellingham (J.M.E.) south to Puget Island (V.B.S.). =Microtus townsendii pugeti= Dalquest _Microtus townsendii pugeti_ Dalquest, Murrelet, 21:7, April 1, 1940. _Type._--Obtained at Neck Point, northwest corner of Shaw Island, San Juan County, Washington, by D. H. Johnson, on July 10, 1938; type in Museum of Vertebrate Zoölogy. _Racial characters._--Size small; skull wide in interorbital region, averaging about 4.0 mm. (3.8-4.2); basi-sphenoid truncate posteriorly; upper incisors strongly curved. _Measurements._--Two males and 6 females average: total length 182.6; length of tail 50.3; hind foot 23.2; ear 15.0. _Distribution._--Found only on the San Juan Islands, San Juan and Skagit counties. _Remarks._--The islands occupied by this race of mouse were heavily glaciated by the last continental glacier (Vashon). Mice of the species _townsendii_ apparently migrated to the islands early in the Recent era, and under isolation developed the differences which now separate them from the mainland population. =Microtus longicaudus= (Merriam) Long-tailed meadow mouse _Description._--The several races of this species vary from small to large in size. Their bodies are relatively longer and slimmer than those of the other meadow mice that occur in Washington. Their most distinctive feature is the long tail, only slightly shorter than the head and body. Their fur is rather coarse. The color varies from grayish brown to dull reddish brown with a brighter brown dorsal stripe. The tail is bicolor; black or dark brown above, yellowish below. The underparts are whitish gray. [Illustration: FIG. 116. Distribution of the long-tailed meadow mouse in Washington. A. _Microtus longicaudus macrurus._ B. _Microtus longicaudus halli._]