16 



NORTH AMEEICAN FAUNA. 



[No. 37. 



small and nearly or quite circular. The feet are robust, witli stout, 

 slightly curved fossorial claws, those on the fore feet somewhat 

 heavier; the thumb of the front foot (in the American species) is 

 rudimentary and often very small, but bears a broad, flat nail; the 

 third digit is the longest, the second and fourth subequal, the fifth 

 decidedly shorter; the palm is naked, bearing 3 pads at the bases 

 of the digits and 2 larger posterior ones; on the hind foot the third 

 digit is slightly longer than the subequal second and fourth, the fifth 

 and first successively much shorter; the sole is naked except at the 

 heel and bears 6 pads, 4 at the bases of the digits and 2 posterior to 

 them. The mammae number 5 pairs, except in the monax group, in 

 which there are usually but 4 pairs. In M. monax, according to 

 Baird, there is a short, shallow cavity between the muscles of the 

 jaw and the cheek, attaining a depth perhaps of haK an inch or less 

 and occupying the place of the internal pouch of Tamias and Sper- 

 mofhilus [CiteUus]J^ ^ 



PELAGE AND MOLT. 



The pelage of the American marmots consists of hairs of two kinds — 

 a dense, soft, and somewhat woolly underfur, confined chiefly to the 

 back and sides; and longer, somewhat coarser hairs covering the 

 whole body, intimately mixed on the back with the underfur and 

 projecting beyond the tips of the latter. The underfm* is of two 

 colors, usually some shade of gray or dark brown tipped with a 

 lighter color, generally a shade of gray, buff, cinnamon, or reddish 

 brown. The long hairs are also of two colors, usually a shade of 

 brown, hazel, or black, tipped with a fighter shade — buff or white. 

 The tips of the underfur usually show thi-ough the long hairs, and 

 form an important element in the general color tone of the pelage. 

 The hairs on the head and feet are shorter than on the rest of the body, 

 and are unicolor to the roots; those on the tail are long and coarse^ 

 their bases of a darker shade than the tips. The hair on the under- 

 parts is shorter and sparser than on the back and is without underfur. 



The pelage is renewed annually in summer, usually in August, 

 sometimes in July or even June, Individuals taken in early spring, 

 soon after emerging from hibernation, are usually in full, long pelage, 

 but by midsummer the pelage often becomes very much worn and 

 faded. There seems to be no uniform method of molting, the new 

 pelage sometimes appearing in patches on various parts of the body. 

 In a specimen of Marmota olympus, taken August 28, the new pelage 

 was coming in in large patches, the molt being farthest advanced on 

 the nuddle of the back, with streaks of new hair along the sides of the 

 neck and body. (See PL II.) In another individual of the same 

 species, taken August 18, new hair was coming in on the rump and 



1 Baird, S. F. Mamm. N. Am., Kept. Expl. and Surv. R. R. Pacif., VIII, 1857, p. 340. The author has 

 had no opportunity to examine specimens of any of the groups in the flesh, so does not kaow whether thi§ 

 .character is possessed by all. 



