=South Dakota.= _Pennington County_: Rapid City, 1. =Wyoming.= _Goshen County_: Fort Laramie, 2. =Mustela frenata oribasus= (Bangs) Long-tailed Weasel Plates 16, 17, 18, 31, 32, 33 and 40 _Putorius (Arctogale) longicauda oribasus_ Bangs, Proc. New England Zoöl. Club, 1:81, December 27, 1899. _Putorius longicauda_, Coues, Fur-bearing animals, p. 136, 1877 (part). _Mustela longicauda oribasus_, Miller, U. S. Nat. Mus. Bull., 79:98, December 31, 1912. _Mustela longicauda oribasa_, Hall, Univ. California Publ. Zoöl., 40:368, November 5, 1934. _Mustela frenata oribasa_, Hall, Carnegie Instit. Washington Publ. 437:105, November 20, 1936. _Type._--Female, adult, skull and skin; no. 9058, collection of E. A. and O. Bangs, but now in collection of Mus. Comp. Zoöl.; source of Kettle River, 7500 feet [the summit between middle fork of Kettle River and Cherry Creek at Pinnacles--oral information from the collector, Feb. 12, 1936], British Columbia; September 10, 1898; obtained by Allan Brooks; original no. 1368. The skull (plate 40) is complete and unbroken. The teeth all are present and entire except right I^3 which has the anterior half broken away. The skin is complete, fairly well made, and in summer pelage. _Range._--Canadian and Hudsonian life-zones from near 56°N in the Rocky Mountains of British Columbia and Alberta and Ootsa Lake along the Fraser and Chilcotin rivers south to Alta Lake, in the Caribou and Monashee mountains, probably in the Selkirks and Rockies, and through the Rockies of Montana into extreme northern Wyoming. See figure 29 on page 221. _Characters for ready recognition._--Differs from _M. f. longicauda_ by near (14 _n_) Brussels Brown rather than near (_h_) Clay Color of upper parts and in males by relatively shallower occiput in which the depth of the skull, exclusive of the sagittal crest and taken at the anterior border of the basioccipital, amounts to less than 59 per cent of the mastoid breadth; from _M. f. nevadensis_ by greater average size, see measurements. _Description._--_Size._--Male: Two adults from Florence, Montana, measure as follows: Total length, 440, 440; length of tail, 165, 161; length of hind foot, 47, 49. Corresponding measurements of an adult male from Quesnel, British Columbia, are: 443; 168; 55. Tail amounts to 60, 58, and 61 per cent as long as head and body. Length of hind foot averages more than basal length. Female: The type specimen, the only typical adult or subadult specimen of this sex of which external measurements are available, measures: Total length, 392, length of tail, 150, length of hind foot, 46. Tail is 63 per cent as long as head and body. Length of hind foot amounts to more than basal length.