I dissected out the glands from the hind feet of an adult male Caribou (No. 1046). Seton (1929, +3+: 68) has discussed these structures in the Woodland Caribou and the Norwegian Reindeer; and Pocock (1911: 960-962, fig. 138B) and Jacobi (1931: 22, fig. 4), in the Reindeer. Many hairs had their base in the glands, and there was a fatty secretion on the hairs adjacent to the glands. I judged that the opening to the exterior extended in a more or less dorso-anterior direction. One of the suggested functions of these glands is anointing the velvet covering of the antlers. I was highly interested, therefore, in seeing an old buck on June 16 rub the tips of its growing antlers with each hind foot in turn. Meanwhile it inclined its antlers alternately to one side and backwards to place one of them at a time within convenient reach of the hind foot on that side. It seemed to rub its snout as well as the antler tips. In Charles Schweder’s experience this action was always carried out with the hind foot, not the forefoot. The latter contains a similar but smaller gland, according to Jacobi (1931: 22), while Pocock (1911: 960-961) gives contrary testimony. On August 27 I also saw a fawn rubbing a knob of its skin-covered antlers with a hind foot. Another function of the foot-glands is suggested by an observation of Dugmore’s (1913: 89-90), which has been mentioned in the section on _Signaling_. I could not definitely connect any of the various occasions of panic that I observed, with scent from the foot-glands of preceding Caribou that had been frightened. _References._--Caton, 1881: 265; Pocock, 1911: 960-962; Seton, 1929, +3+: 68, 105; Sutton and Hamilton, 1932: 84; Harper, 1949: 230. _Mastology_ Very little seems to have been published on this subject. Jacobi (1931: 24) merely remarks that in the Reindeer the mammae number four, or occasionally six, but that the supernumerary ones are not functional. The four rudimentary mammae in a male fawn of _arcticus_ (No. 1072) of August 20 seemed remarkable for their arrangement in a nearly straight transverse row--quite different from the more rectangular pattern in a domestic Cow or in a male Moose, as figured by Seton (1929, +3+: 221). In an adult doe (No. 1101) of September 21 the anterior pair are about twice as far apart as the posterior pair; each of the mammae appears no more than a couple of inches from the one nearest to it. The arrangement in a two-year-old buck, as shown by Seton (1929, +3+: 106), is approximately intermediate between linear and rectangular. _Fat_