=Ondatra zibethicus osoyoosensis= (Lord) _Fiber osoyoosensis_ Lord, Proc. Zoöl. Soc. London, p. 97, 1863. _F[iber]. z[ibethicus]. osoyoosensis_ Hollister, Proc. Biol. Soc. Washington, 23:1, February 2, 1910. _Ondatra zibethica osoyoosensis_ Miller, U. S. Nat. Mus. Bull., 79:231, December 31, 1912. _Type._--Obtained at Osoyoose Lake, British Columbia, on British Columbia-Washington boundary at head of Okanogan River, by J. K. Lord, in 1861 or 1862. _Racial characters._--Color of the upper parts rich, dark brown. _Measurements._--Two males and a female from Seattle, King County, average and measure respectively: total length 565, 555; length of tail 262, 257; hind foot 80.5, 79; weight 2 pounds 13 ounces and 2 pounds 3 ounces. _Distribution._--Eastern Washington generally and all but the southern part of western Washington. Specimens from as far southwest as Tenino (W.W.D.) are typical of _osoyoosensis_. =Ondatra zibethicus occipitalis= (Elliot) _Fiber occipitalis_ Elliot, Field Columb. Mus. Publ. 74, zoöl. ser., 3:162, April, 1903. _Ondatra zibethica occipitalis_ Miller, U. S. Nat. Mus. Bull., 79:231, December 31, 1912. _Type._--Obtained at Florence, Lane County, Oregon, by E. Heller, in 1901; type in Chicago Natural History Museum. _Racial characters._--Similar to _osoyoosensis_ but redder; fur shorter and interpterygoid spaces of skull narrower. _Measurements._--A male from Chinook, Pacific County, measures: total length 580; length of tail 248; hind foot 78; ear 21; weight 863 grams. _Distribution._--The southwestern corner of the state, extending north to Aberdeen (V.B.S.) and east to Cathlamet (V.B.S.). =Rattus rattus= (Linnaeus) Roof rat _Description._--Size large, total length approximately 400 mm.; tail long, naked, comprising 50 per cent or more of total length; color sooty black or brown; in brown phase, whitish beneath. The roof rat became established in Central America some 350 years ago, and entered the United States (English Colonies) late in the seventeenth century. Subsequent to the introduction of the Norway rat the roof rat decreased in numbers and is now found only in restricted areas. =Rattus rattus rattus= (Linnaeus) _[Mus] rattus_ Linnaeus, Syst. Nat., 1 (ed. 10):61, 1758. _Rattus rattus_ Hollister, Proc. Biol. Soc. Washington, 26:126, June 6, 1916. _Type._--From Uppsala, Sweden. _Remarks._--In Washington I have taken specimens of the roof rat in the San Juan Islands and in the coniferous forests on the west slope of the Cascades. In the latter area it seems to be widely spread and to live in the wild. =Rattus rattus alexandrinus= (Geoffroy) _Mus alexandrinus_ Geoffroy, Catal. Mam. du Mus. Nat. d'Hist. Nat. Paris, p. 192, 1803.