Plate 18. Photographs, retouched, of skulls in lateral view of ten subspecies of Mustela frenata. Natural size.
a. Mustela frenata noveboracensis, ♂ ad., 77112, U. S. Nat. Mus., Wilmington, Mass.
b. Mustela frenata occisor, ♂ ad., 7267, M. C. Z., Moosehead Lake, Maine.
c. Mustela frenata primulina, ♂ ad., 3325, Mus. Nat. Hist., Univ. Kansas, Clinton, Kans.
d. Mustela frenata arthuri, ♂ ad., 37515, Mus. Vert. Zoöl., type, Remy, Louisiana.
e. Mustela frenata olivacea, ♂ ad., 180802, U. S. Nat. Mus., type, Biological Surveys Collection, Autaugaville, Alabama.
f. Mustela frenata peninsulae, ♂ ad., 49387, Florida State Mus., Apopka, Florida.
g. Mustela frenata spadix, ♂ ad., 53795, Mus. Vert. Zoöl., Elk River, Minnesota.
h. Mustela frenata longicauda, ♂ ad., 15875, Amer. Mus. N. H., Red Deer, Alberta.