76 EXTINCT AND VANISHING MAMMALS 



its tributaries. In 1919, after two years of open season on 

 beavers, many of the small colonies were reduced or wiped out; 

 "a few traces of their work were found along the Missouri 

 River at Sanish and Bismarck, and there were said to be a few 

 beavers still in Apple Creek and Burnt Creek. Near the mouth 

 of the Cannonball River they were very scarce, although they 

 had been fairly common up to 1916." Where cutting of trees 

 seems too evident, the local residents often become exasperated 

 and demand the killing-off of the animals, although the loss of 

 the trees and at times that of the grain growing near at hand 

 is less than the value of the beavers. 



It is perhaps this form of beaver that was formerly common 

 on some of the rivers of northern and western Kansas. Hibbard 

 (1933, p. 241) writes of its recent status, that although once 

 common throughout the State, along the large streams, it was 

 exterminated from many parts by early trappers; a few, re- 

 ferred to this race, are still "found in small scattered colonies 

 along the Republican, and the Kaw east into Douglas County, " 

 of eastern Kansas, while a few colonies are reported along the 

 Arkansas River in the western part of the State. 



NORTHWEST COAST BEAVER 

 CASTOR CANADENSIS PACIFICUS Rhoads 



Castor canadensis pacificus Rhoads, Trans. Amer. Philos. Soc., ser. 2, vol. 19, p. 422, 

 Sept. 1898 (Lake Keechelus, Cascade Mountains, Kittitas County, Washington). 



CASTOR CANADENSIS IDONEUS Jewett and Hall 



Castor canadensis idoneus Jewett and Hall, Journ. Mammalogy, vol. 21, p. 87, fig. la, 

 Feb. 1940 (Foley Creek, Nehalem River, Tillamook County, Oregon). 



The beaver of the northwest coast from most of Oregon 

 northward into southern British Columbia was described by 

 Rhoads as a distinct race in 1898, but for many years thereafter 

 this name was considered a synonym of leucodonta, the Van- 

 couver Island race. In 1916, however, Taylor in his review of 

 the western beavers, reestablished it as a distinct subspecies. 

 Its characters are slight and relate principally to the form of 

 the nasal bones, which "in pacificus have their outlines some- 

 what more invaded laterally by the backward-extending 

 tongues of the premaxillaries, " beyond which their lateral out- 

 lines again become somewhat more parallel. This posterior 



