Although the Pronghorn is here described after all the more ordinary hollow-horned Ruminantia, it is far from impossible that it is much more intimately related to some one of the above-mentioned families than to the others. It must either have originated direct from the earliest type of Bovine Ruminant, and from that time continued isolated until the present day, or it may have been a straggler from some already differentiated group, like the Gazelles, for instance, that, arriving in a land so unlike the haunts of its progenitors, took on itself from altered circumstances peculiar modifications in its horn-growth and foot-form which have resulted in its present characteristics. THE MUSK [DEER].[27] This interesting animal, from the male of which is obtained a powder contained in a pouch about the size of an orange, on the surface of the abdomen, and which is one of the most fragrant of perfumes, is generally included among the Cervidæ. Nevertheless, there are many reasons in favour of its being considered an Antelopine animal. Apart from the fact that it has a gall-bladder, which is not found in any Deer, but in almost all Antelopes, its pale grey hair is peculiarly coarse and Goat-like, and the absence of antlers or horns in both sexes tells in neither direction, for, as in the Brockets of South America and the Chinese Muntjac, the antlers are rudimentary, so are the horns in the Bush-bucks of Africa, and in some domestic Sheep as well as Oxen. The presence of enormous canine tusks, three inches long, would at first sight seem to be in favour of its relations with the Deer, because in the Muntjacs they are also found. Nevertheless there is no _à priori_ reason why these formidable weapons should not be developed in a hollow-horned ruminant; for, cropping up independently in genera so distant as the Deerlets, the Muntjacs, and the Water Deer, why should they not do so in the Antelopes as well? [Illustration: SKULL OF THE MUSK [DEER].] The Musk is twenty inches in height, its ears large, and its tail rudimentary. Its hoofs are small, but their spread is large, because of the yielding attachment of the false hoofs, as in the Reindeer. The coarse and brittle hair is grey and slightly brindled. Its habitat is Central Asia, from the Himalaya Mountains to Pekin, at elevations above 8,000 feet.