h. Mustela erminea alascensis, ♂ ad., 74665, Mus. Vert. Zoöl., Windham, Alaska.

i. Mustela erminea salva, ♂ ad., 74641, M. V. Z., Mole Harbor, Admiralty Id., Alaska.

Plate 4. Photographs, retouched, of skulls in lateral view of ten subspecies Mustela erminea. Natural size.

a. Mustela erminea arctica, ♂ ad., 178405, U. S. Nat. Mus., Tanana, Alaska.

b. Mustela erminea semplei, ♂ sad., 6499, Carnegie Mus., Southampton Island.

c. Mustela erminea kadiacensis, ♂ ad., 107496, U. S. N. M., Kodiak Island, Alaska.

d. Mustela erminea richardsonii, ♂ ad., 133847, U. S. N. M., Ft. Franklin, MacK.

e. Mustela erminea cicognanii, ♂ ad., 53788, Mus. Vert. Zoöl., Lopez, Pennsylvania.

f. Mustela erminea bangsi, ♂ ad., 18130, Field Mus. Nat. Hist., Aitkin, Minn.