The most successful results, however, in breeding the White-tailed Gnu have been obtained by Mr. F. E. Blaauw, Secretary to the Royal Zoological Society of Amsterdam, in his park at Westerveld, near Hilversum, in North Holland, on which he has been kind enough to furnish us with the following information:--Mr. Blaauw purchased his first pair of Gnus in 1886 from the Jardin d’Acclimatation at Paris. They arrived in winter and were kept in a covered shed without artificial warmth until the following spring, when they were turned out to a grass enclosure of about eight acres, well sheltered by plantations, and with a shed divided into compartments in one corner. The Gnus and their descendants have been kept in this enclosure ever since. In winter they are usually confined inside the house and fed on hay and oats, because the young ones are frequently born in winter and require a certain amount of protection. In the summer the Gnus never enter the shed, and subsist entirely by grazing. Treated in this fashion the Gnus in Mr. Blaauw’s possession have succeeded in a wonderful way. From the single pair originally purchased and the two young females first born, no less than fourteen young Gnus have been successfully reared, and only two have been lost, having been born in the open field during severe frost. Mr. Blaauw’s present herd consists of the original pair purchased in 1886, two adult females (the offspring of this pair born in 1886 and 1887), and two young ones born in May and June of the present year. Mr. Blaauw has ascertained by frequent observation that the period of gestation in the White-tailed Gnu varies from 8¼ to 8½ months. Only a single young one has ever been produced at a birth. The female suckles her young for seven or eight months, but it commences to eat grass when about a week old. In the ‘Proceedings’ of the Zoological Society of London, Mr. Blaauw has published an article on the development of the horns of the young Gnu, two of the figures of which we are enabled to reproduce here by the kind permission of that Society. The first figure (15 _b_) represents the first stage of the horns, in which they are perfectly straight and more or less divergent; the second figure (15 _c_) represents the horns when the animal is about 19 months old. The former straight portion has now become the terminal half, and the basal portion, though not yet quite fully developed, inclines downwards and outwards. The bases of the horns are still far apart, and there is a wide piece of hairy scalp between them. In the adult stage (as shown in Plate XII.) the basal ends of the horns become enormously swollen (especially in the male) and nearly meet together in the middle line. It should be further remarked that these swollen basal portions, which are smooth at first, become excessively corrugated and more highly developed when the animals get old. [Illustration: Fig. 15 _b_. Horns of young Gnu (11 weeks old). (P. Z. S. 1889, p. 2.)]