_Range._--Maine; possibly north locally to south side of St. Lawrence River in Quebec and possibly occurring in western New Brunswick. Zonal range Canadian and probably Transition. See figure 29 on page 221.
_Characters for ready recognition._--Differs from _M. f. noveboracensis_ by a number of average differences including larger size, relatively longer tail and relatively wider skull (see p. 225, and measurements on pp. 418, 419).
_Description._--_Size._--Male: Five adults yield average and extreme measurements as follows: Total length, 443 (430-465); length of tail, 163 (154-175); length of hind foot, 50 (47-54). Tail averages 58 per cent as long as head and body. Length of hind foot averages more than basal length.
Female: Measurements of two subadult female topotypes are as follows: Total length, 346, 318; length of tail, 116, 110; length of hind foot, 39, 35.5.
Tail amounts to 50 per cent and 54 per cent of body-length respectively. Length of hind foot more or less than (about equal to) basal length.
The average differences in external measurements of the two sexes are: Total length, 111; length of tail, 50; length of hind foot, 12.5.
_Externals._--As described in _Mustela frenata noveboracensis_.
_Color._--As described in _Mustela frenata noveboracensis_ except that black tail-tip in series of 10 males in full winter pelage 60 (45-80) mm. long; thus averaging 39 per cent of length of tail vertebrae.
_Skull and teeth._--Male (based on 3 adults): See measurements and plates 16-18. As described in _Mustela frenata noveboracensis_ except that: Weight, 4.2 (4.1-4.3) grams; basilar length, 45.7 (44.9-46.9); zygomatic breadth more or less than (about equal to) distance between anterior palatine foramen and anterior margin of tympanic bulla; least width of palate rarely less than length of P4; anterior margin of masseteric fossa behind or directly below posterior half of m2.
Female (based on 2 subadults): See measurements and plates 31-33. As described in _Mustela frenata noveboracensis_ except that: Weight, 2.0 (1.9-2.1) grams; basilar length, 37.3, 38.2.
Comparison of the skull with that of _M. f. noveboracensis_ is made in the account of that subspecies.
_Remarks._--Excepting a specimen in the Academy of Natural Sciences of Philadelphia, obtained in 1893, and two in the Boston Society of Natural History, obtained in 1925, I have seen no material of this subspecies in addition to that examined by Bangs at the time he prepared the original description in 1899.