The display in systematic and serial order of the external characters and internal anatomy of the leading types of living and extinct animals and plants formed, however, only a part of Flower’s scheme of exhibits for the central hall of the museum. Such specimens occupied only the “bays” or alcoves on the west and east sides, and there remained the large central floor space for exhibits of other descriptions. Advantage was taken of this to display examples of the phenomenon of seasonal colour-change in birds, accompanied in some instances, as in the ruff, by the development of special plumes round the neck, or elsewhere; the two species selected for illustration being the aforesaid ruff and the wild duck or mallard; the latter bird, together with many other members of its tribe, being remarkable on account of the assumption by the males at certain seasons of the year of an “eclipse” plumage, almost indistinguishable from that distinctive at all times of the year of the female. Other cases were devoted to showing some of the more remarkable kinds of variation produced from a single wild stock by domestication and artificial selection; the species exhibited for this purpose being several types of the common fowl, the various kinds of pigeons, and the more remarkable strains of the canary. The introduction of domesticated breeds, whose peculiarities are entirely, in the outset at anyrate, the result of man’s interference with the ordinary course of Nature, is a notable feature of this portion of the work of Flower, and indicates his sense of the important bearing of such artificial variations on the doctrine of the evolution of organic nature. “Mimicry” by animals of one group of those of another also formed an important part of this introductory series of exhibit; as did likewise the colour-adaptation of animals to their inorganic surroundings. This latter phenomenon is specially illustrated by a series of animals (mammals, birds and reptiles) from the Libyan desert, which are set up amid rocks and sand from the same locality so as to imitate as nearly as possible the natural conditions. And this case, together with one of these to be noticed immediately, affords an excellent example of Sir William’s painstaking efforts to make the exhibits in the museum as realistic as possible, and also his influence and persuasive power in inducing friends or correspondents to aid his endeavours. For in both these instances the animals and their inanimate surroundings were collected on the spot by generous and enthusiastic donors. The second instance of the adaptation of animals to their surroundings is afforded by the two cases displaying respectively a summer and a winter scene in Norway, with the birds and mammals in the one in their brown dress, and in the other in their snow-white livery. Since Sir William’s death an Arctic fox, in the appropriate dress, had been added to each case, with a decided improvement to the general effect.