188 MICROTUS. 



Genl. Char. Size medium, tail short. Similar to M. operarius. 



Color. Above dull fulvous brown and black; beneath whitish 

 tinged with buff; hind foot brown; toes partly whitish. Tail, dusky 

 above, whitish beneath. 



Measuretnen/s. Skin. Tail, 29; hind foot, 18.5. 



273. yakutatensis. {Micro/ iis), Merr., Proc. Wash. Acad. Scien., 



1900, p. 22. 



Type locality. Yakutat Bay, Alaska. 



Geogr. Distr. Glacier Bay to Prince William Sound, Alaska. 



Genl. Char. Size medium; tail very short, similar to M. siiken- 

 sis, but with shorter feet. Cranial characters as in J/, sitkensis. 



Color. Above grayish brown, black, and buffy fulvous; beneath 

 whitish, or buffy white; feet whitish, soles black. Tail, above black- 

 ish, beneath whitish or buff. 



Measurements. Total length, 172; tail vertebra^, 38; hind foot, 21. 



274. kadiacensis. {Microtus), Merr., Proc. Biol. Soc. Wash.. 1897, 



p. 222. 



Type locality. Kadiak Island, Alaska. 



Geogr. Distr. Kadiak Island, Alaska. 



Genl. Char. Similar to M. sitkensis, but smaller and paler. 

 Teeth as in M. sitkensis, but first lower molars with only two closed 

 loops on each side. 



Color. Above pale grizzled brownish, suffused with pale ful- 

 vous, lined with black; under parts plumbeous washed with white. 

 Tail, dusky above, white beneath. Feet grayish brown. 



Measurements. Total length: "Average of five adult males, 

 188; tail vertebrae, 50; hind foot, 21." 



275. unalascensis. {Microtus), Merr., Proc. Biol. Soc. Wash., 1897, 



p. 222. 



Type locality. Unalaska, Alaska. 



Geogr. Distr. Unalaska Island, Alaska. 



Genl Char. Similar to M. kadiacensis, but darker; audital bullae 

 shorter; first lower molar with two closed and two open internal 

 loops, and two closed external. 



Color. Above yellowish brown; bent_-ath plumbeous washed 

 with whitish. Tail, black above, white below. Feet grayish. 



Measurements. Total length, 122; tail vertebrae, 28; hind foot, 19. 



II. — uniiofrnsif^. {Microtus), Merr., Proc. Wash. Acad. Scien., 1900, 

 p. 22. 

 Type locality. Popof Island, Shumagin Group, Alaska. 

 Genl. Char. Similar externally to M. unalascensis, but cranium 



