Plate 9. Photographs, retouched, of skulls in dorsal view of 9 subspecies of Mustela erminea. Natural size.
a. Mustela erminea arctica, ♀ ad., 35895, Field Mus. Nat. Hist., Point Barrow, Alaska.
b. Mustela erminea semplei, ♀ ad., 6600, Carnegie Mus., Southhampton Island.
c. Mustela erminea kadiacensis, ♀ ad., 98042, U. S. Nat. Mus., Kadiak, Alaska.
d. Mustela erminea richardsonii, ♀ ad., 129703, U. S. N. M., Fort Resolution, MacK.
e. Mustela erminea cicognanii, ♀ ad., 7460, Carnegie Mus., Pymatuning Swamp, Pa.
f. Mustela erminea bangsi, ♀ ad., 8679, Univ. Wisconsin, T. 61N, R. 26W, Minn.
g. Mustela erminea invicta, ♀ ad., 90820, M. V. Z., 1-1/2 mi. W Iron Mtn., Idaho.
h. Mustela erminea alascensis, ♀ ad., 74422, U. S. Nat. Mus., Juneau, Alaska.
i. Mustela erminea salva, ♀ ad., 74655, Mus. Vert. Zoöl., Mole Harbor, Alaska.