1865.] DR. J. E. GRAY ON THE MUSTELID&. 107 
Mustela leucopus, Kuhl, Beitr. 70. 
Mustelu leucotis, Griffith’s An. K. ii. 270, t. (misprint ?). 
M. Brandt observes, “I can find no difference between the Asiatic 
and American Sables in the characters of the head, ears, tail, or feet; 
and as, even in respect to colour, the sable of the Nischnaga Tun- 
zustca, sent home by Middendorf, occupies an intermediate position 
between the dark Asiatic and the yellow American Sables, I am 
induced to consider the American animal rather as a yellowish or 
mere yellow-brown and less densely furred variety of the Asiatic 
Sable than as a distinct species or as a pure Marten (Mustela 
martes). — Beitr. Séugeth. Russland, 1855. 
Dr. Baird observes, “I am myself, however, far from admitting 
the identity of the American Marten with the Russian Sable, although 
it occupies a position intermediate between the latter and M. 
martes in size, length of tail, and coloration, as well as intrinsic 
value of fur. The white-headed varieties of New York are most like 
the Sable, and the dark-headed one of the western country like the 
Pine-Marten. I have never seen winter specimens of the latter, nor 
summer of the former, and am inclined to believe that all may ex- 
hibit more white on the head in winter than in summer.’’—Baird, 
le. 157. 
It is curious that both Brandt and Baird seem to have overlooked 
the small size of the last tubercular grinder, which separates the 
American from the Old-World Pine-Martens. 
The brain-case in the skull of the American specimen we have in 
the Museum is very thin, and so closely applied to the brain that it 
shows its convolutions on the outer surface; but this is not shown 
in the American skull figured by Dr. Spencer Baird. The same is 
to be observed in the Altaic specimen of M. abietum. 
There is a series of specimens of the American Pine-Marten in the 
British Museum, collected by Dr. Lord during his excursion with 
the Boundary Commissioners. They vary greatly in colour, from 
pale brown to nearly black; and the throat is variously mottled with 
ellow. 
The specimens from Russia have whitish heads, like the M. leu- 
copus of Kuhl. 
The stuffed Sables from Russia have short tails; but the tail of 
one of Dr. Lord’s is almost as short: the tail seems to vary in length; 
but this may depend on the skinning, and, in the stuffed skins, on 
the preparation of the animals. 
** Tail elongate, slender; skull elongate, narrow ; nose produced; 
upper tubercular grinder massive, broader on the inner side. 
Pekania. 
7. MarTEs PENNANTII. The Wood-Shock. 
Black ; head, nape, and front of back greyish ; tail elongate. 
Mustela pennantii, Erxl. Anim. 79, 1777; Baird, Mamm.N. A. 
149, t. 36. f. 1, skull. 
Mustela canadensis, Schreb. Siiugeth. 492, t. 134, 1778; Rich- 
