The outstanding features of Orcadian zoology are naturally the very restricted number of land mammals as compared with that of the neighbouring mainland of Scotland, the relatively large number of cetaceans in the surrounding waters, and, above all, the richness of the avifauna, particularly in sea-birds, and autumn and winter visitants from more northerly climes. Although the bones and antlers of the red deer have been found among the matter excavated from the sites of brochs and Picts’ houses, and their shed horns at times turn up among the peat-mosses of the Mainland, that king of British Cervidæ was unknown to Orkney during historic times until about the year 1860, when two young hinds and a young stag were introduced into Walls. There they throve perfectly, and had increased to thirteen or fourteen by 1870-72, when the proprietor of the island found it necessary to kill them off, on account of the damage which they were doing to crops. Tusks of the wild boar have been found at Skaill in the West Mainland, but the wolf, fox, badger, and in fact practically all of the larger land mammals known to Britain during historic times, or still found there to-day, have been totally unknown in Orkney during the same period. The otter is a notable exception, as it is very abundant in most of the islands, the great extent of sea-board giving it special facilities for concealment and avoidance of capture. An Orcadian proprietor who died a few years ago has recorded that in his young days he often had as many as thirty otter skins in his possession at one time.