The class of animals to which the restrictive laws of geographical distribution might seem least applicable is that of birds: their peculiar power of locomotion, associated in numerous species with migratory habits, might seem to render them independent of every influence, save those of climate and of food, which directly affects the conditions of their existence. Yet the long-winged albatross is never met with north of the equator; nor does the condor soar above other mountains than the Andes. The geographical range of its European representative, the strong-winged lammergeyer, is similarly restricted. The Asiatic Phasianidæ and Pavonidæ are represented by turkeys (Meleagris) in America; by the guinea-fowl (Numida Agelastus, Phasidus) in Africa, and by the Megapodiæ or mound birds in Australia. Several genera of finches are peculiar to the Galapagos Islands; the richly and fantastically ornate birds of paradise are restricted to New Guinea and some neighboring isles. Mr. Sclater, who has contributed the latest summary of facts on the distribution of birds, reckons seventeen families as peculiar to America and sixteen families as peculiar to Europe, Asia, and Africa. Some species have a singularly restricted locality, as the red-grouse (Tetrao scoticus) to the British Isles; the owl-parrot (Nestor productus) to Philip Island, a small spot near New Zealand. When birds have wings too short for flight, we marvel less at their restricted range; and particular genera of brevipennate birds have their peculiar continents and islands. The long and strong-limbed ostrich courses over the whole continent of Africa and conterminous Arabia. The genus of three-toed ostriches (rhea) is similarly restricted to South America. The emeu (Dromaius) has Australia assigned to it. The continent of the cassowary (Casaurius) has been broken up into Sumatra, Java, Banda, and other islands, extending from the southeastern peninsula of Asia to New Guinea. A second species of cassowary has recently been imported to our zoological gardens from the more southern island of New Britain. The singular nocturnal wingless kivi (apteryx) is peculiar to the island of New Zealand. Other species and genera which seem to be like the apteryx, as it were mocked with feathers and rudiments of wings, have wholly ceased to exist within the memory of man in the islands to which they were respectively restricted. The dodo (Didus ineptus) of the Mauritius, and the solitaire (Pezophops solitaria) are instances.