_Comparisons._--From topotypes of _Clethrionomys gapperi wrangeli_, _C. g. solus_ differs as follows: dorsal stripe wider and slightly brighter; sides brighter; venter more heavily washed with Ochraceous-Tawny (heavy wash in all 13 _C. g. solus_ examined; in _C. g. wrangeli_ no wash in 11, slight wash in 16, and heavy wash in only one); nasals, alveolar extent of upper cheek-teeth and incisive foramina shorter; skull shallower when measured with tympanic bullae included; rostrum averages slightly broader. From _C. g. phaeus_ of the adjacent mainland, _C. g. solus_ differs in: dorsal stripe slightly darker; ventral wash more prominent; tail shorter; skull smaller in all parts measured except that nasals are approximately the same length, auditory bullae notably smaller and teeth notably narrower. _Measurements._--External and cranial measurements of adults are shown in table 1. _Remarks._--Bailey (Proc. Biol. Soc. Washington, 11:120, May 13, 1897) referred 17 specimens from Loring to his newly named species, _E. wrangeli_ [= _Clethrionomys gapperi wrangeli_] but based his description on specimens from Wrangell Island. He pointed out (_loc. cit._) that all of the specimens from Loring had the "bellies strongly washed with buffy-ochraceous, while more than half of those from Wrangell have whitish bellies." _Specimens examined._--Total, 13, all in the Biological Surveys Collection, U. S. National Museum, from the following localities: Alaska: Revillagigedo Island: Loring, 10; mouth of Fish Creek, Ketchikan, 3. Clethrionomys gapperi stikinensis, new subspecies _Type._--Male, adult, skin and skull, No. 30735, Museum of Vertebrate Zoology, University of California; from Stikine River at Great Glacier, British Columbia; obtained on August 13, 1919, by J. Dixon; original number 7691. _Range._--Known only from the lower Stikine River Valley of British Columbia and the Cleveland Peninsula of Alaska. _Diagnosis._--A medium-sized, dark-colored member of the _gapperi_ group. Dorsal stripe wide, near Auburn with mixture of black-tipped hairs; sides and venter washed with Ochraceous-Tawny. Skull small; cheek-teeth narrow; auditory bullae relatively uninflated. _Comparisons._--From topotypes of _Clethrionomys gapperi wrangeli_, _C. g. stikinensis_ differs as follows: dorsal stripe slightly wider and brighter; sides slightly duller (lacking the olivaceous wash of _C. g. wrangeli_); all cranial measurements taken averaging smaller except height of skull, which is approximately the same; alveolar length of upper tooth-row and length of incisive foramina notably shorter; auditory bullae less inflated; cheek-teeth much narrower.