At the present time the musk-ox inhabits only arctic America, from Greenland westward nearly to the Mackenzie River, but its range was formerly circumpolar, and in Pleistocene times it inhabited Europe as far south as Germany and France.  The musk-ox of Greenland has lately been set aside as a distinct species.  The most we can say is that Ovibos is a unique form, standing perhaps somewhere between oxen and sheep, and descended from an ancient ruminant type through an ancestry of which we know nothing, for the only fossil remains which are at all distinguishable from the existing genus, are yet closely similar to it, and are no older than the Pleistocene of the central United States; in earlier periods its history is a blank about which it is useless to speculate.

The last of our three anomalies, the white, or mountain goat (Oreamnos montanus), is not as completely orphaned as the other two, for it seems quite surely to be connected with a small and peculiar series consisting of the European chamois and several species of Nemorhaedus inhabiting eastern Asia and Sumatra.  These are often called mountain antelopes, or goat antelopes.  So little is yet known of the soft anatomy of the white goat that we are much in the dark as to its minute resemblances, but its glandular system is certainly suggestive of the chamois, and many of its attitudes are strikingly similar.  In all the points in which it approaches goats it is like some, at least, among antelopes, while in the elongated spines of the anterior dorsal vertebrae, which support the hump, and in extreme shortness of the cannon bone, it is far from goat-like.  The goat idea, indeed, has little more foundation than the suggestive resemblance of the profile with its caprine beard.  It is truly no goat at all, and should more properly be regarded as an aberrant antelope, if anything could be justly termed “aberrant” in an aggregation of animals, hardly any two of which agree in all respects of structure.  No American fossils seem to point to Oreamnos, and as Nemorhaedus extends to Japan and eastern Siberia, it is probable that it was an Asiatic immigrant, not earlier than the Pleistocene.

From this intricate genealogical tangle one turns with relief to the deer family, where the course of development lies reasonably plain.  If the rank of animals in the aristocracy of nature were to be fixed by the remoteness of the period to which we know their ancestors, the deer would out-rank their bovine cousins by a full half of the Miocene period, and the study of fossils onward from this early beginning presents few clearer lines of evidence supporting modern theories respecting the development of species, than is shown in the increasing size and complexity of the antlers in succeeding geological ages, from the simple fork of the middle Miocene to those with three prongs of the late Miocene, the four-pronged of the Pliocene, and finally to the many-branched shapes