_Skull._--Male (type and 4 adult topotypes): See measurements and plates 2-4. As described in _Mustela erminea richardsonii_ except that: Weight, 1.7 (1.5-1.9) grams; basilar length, 37.8 (36.4-39.5, extremes are in subadults); length of tooth-rows more or less (usually more) than length of tympanic bulla; interorbital breadth rarely more than distance between glenoid fossa and posterior border of external auditory meatus.
Female (2 ad. and 1 ad.-sad. topotypes): See measurements, and plates 9-11. As described in _Mustela erminea richardsonii_ except that: Weight, 0.9 (0.8-1.0) grams; basilar length, 33.0 (32.0-33.6); length of tooth rows approximately same as length of tympanic bulla; breadth of rostrum approximately 30 per cent of basilar length.
From _alascensis_, _salva_ differs in that males have the preorbital region slightly wider in relation to the length of the tympanic bulla; also the braincase is smaller, actually as well as in comparison with the preorbital part of the skull. The tympanic bullae do not project so far below the squamosals and the braincase itself is shallower, in adults averaging only 11.5 mm. as against 12.5 mm. The overall depth of the braincase, including the tympanic bullae, when divided into the orbitonasal length gives an average of 93 (90-97) per cent whereas in _alascensis_ the figure is only 85 (78-88) per cent. On this basis alone, everyone of the adult skulls of the two races can be distinguished. The females and subadult males show the same tendency to reduction in depth of braincase but not every individual among them can be surely distinguished. By weight the skull of _salva_ of corresponding sex is only about 6 per cent smaller. Comparisons with _initis_ and _celenda_ are made in the accounts of those subspecies.
_Remarks._--Most of the specimens seen were collected by Allen E. Hasselborg, resident on Admiralty Island. On the basis of skulls--few skins, and measurements taken in the flesh, are available--_salva_ more closely resembles _alascensis_ than does any other subspecies so far known from southeastern Alaska. The race on Admiralty Island is only slightly differentiated from _alascensis_ of the adjacent mainland.
_Specimens examined._--Total number, 26, all from Admiralty Island, Alaska, arranged in general by localities from north to south, and unless otherwise indicated in the Museum of Vertebrate Zoölogy, University of California.