The African Spur-Winged Goose, (_Plectropterus gambensis_), although of large size, is more properly a duck than a goose. A long sharp spur arises from the bend of each wing, which the birds use in fighting with each other for their mates. The Gray-Lag Goose, (_Anser anser_), is, perhaps, the most interesting of all geese, as being the wild species from which our domestic birds are descended. The white color and large size are the chief differences between the domestic and wild birds. The White-Fronted Goose, (_Anser albifrons_), is worthy of special notice because it is the handsomest of the ten species of North American geese. The breeding grounds are far to the north, and in Alaska the nests are mere hollows in the sand, lined with moss and down. The Bar-Headed Goose, (_Eulabia indica_), inhabits the mountains of Central Asia, nesting always over a mile above the sea. It is perhaps the handsomest of all geese. The Swans.—Usually at least six out of the seven known species of swans may be seen on exhibition here. The Mute Swan, (_Cygnus olor_), is the commonest swan in captivity, and is the one made famous in European history and legend. It may always be known from the other species by the black knob at the base of the bill. It breeds freely in captivity and the young birds are known as cygnets. The Trumpeter Swan, (_Cygnus buccinator_), being the largest bird in the aviary, and also snowy white, is therefore the most conspicuous. Several fine specimens are shown on the North Island, living contentedly with other species. Some of these specimens were captured in Idaho, when young enough to take kindly to captivity. The Black Swan, (_Chenopsis atrata_), of South Australia and Tasmania, is as glossy black, excepting its primaries, as other swans are white. It is a large and handsome bird, and much sought by all persons who form collections of water fowl. The Coscoroba Goose, (_Coscoroba coscoroba_), is a fair connecting link between the swans and the ducks, partaking about equally of the characters of each. In size and color it is very much like our snow goose, (_Chen hyperborea_), but it is peculiar in possessing very long legs of a bright pink color, by which it is quickly recognized. Its bill, also is pink, and the tips of its primaries are black. The Coscoroba Goose is a native of southern South America, and a few years ago specimens were so rare in captivity that a pair sold for $300. THE FLYING CAGE, No. 4. This mammoth bird-cage is one of the wonders of the Zoological Park. It represents an attempt to do for certain large and showy water birds, precisely what has been done for the hoofed animals, the beaver, otter, and other species—give them a section of Nature’s own domain. In this they can fly to and fro, build nests and rear their young in real freedom.