The Oriental region comprises all tropical Asia east of the Indus, with the Malay Islands as far as Java, Borneo, and the Philippines. In its actual land-area it is the smallest region except the Australian; but if we take into account the wide extent of shallow sea connecting Indo-China with the Malay Islands, and which has, doubtless, at no distant epoch, formed an extension of the Asiatic Continent, it will not be much smaller than the Ethiopian region. Here we find all the conditions favourable to the development of a rich and varied fauna. The land is broken up into great peninsulas and extensive islands; lofty mountains and large rivers everywhere intersect it; while along its northern boundary stretches the highest mountain-range upon the globe. Much of this region lies within the equatorial belt, where the equability of temperature and abundance of moisture produce a tropical vegetation of unsurpassed luxuriance. We find here, as might be expected, that the variety and beauty of the birds and insects is somewhat greater than in the Ethiopian region; although, as regards mammalia, the latter is the most prolific, both in genera, species, and individuals.

The families of Mammalia actually peculiar to this region are few in number, and of limited extent. They are,—the Galeopithecidæ, or flying lemurs; the Tarsiidæ, consisting of the curious little tarsier, allied to the lemurs; and the Tupaiidæ, a remarkable group of squirrel-like Insectivora. There are, however, a considerable number of peculiar genera, forming highly characteristic groups of animals—such as the various apes, monkeys, and lemurs, almost all the genera of which are peculiar; a large number of civets and weasels; the beautiful deer-like Chevrotains, often called mouse-deer; and a few peculiar antelopes and rodents. It must be remarked that we find here none of those deficiencies of wide-spread families which were so conspicuous a feature of the Ethiopian region—the only one worth notice being the dormice (Myoxidæ), a small family spread over the Palæarctic and Ethiopian regions, but not found in the Oriental.

The birds of the Oriental region are exceedingly numerous and varied, there being representatives of about 350 genera of land-birds, of which nearly half are peculiar. Three families are confined to the region—the hill-tits (Liotrichidæ), the green bulbuls (Phyllornithidæ), and the gapers (Eurylæmidæ); while four other families are more abundant here than elsewhere, and are so widely distributed throughout the region as to be especially characteristic of it. These are—the elegant pittas, or ground-thrushes (Pittidæ), the trogons (Trogonidæ), the hornbills (Bucerotidæ), and the pheasants (Phasianidæ); represented by such magnificent birds as the fire-backed pheasants, the ocellated pheasants, the Argus-pheasant, the pea-fowl, and the jungle-fowl.

Reptiles are very abundant, but only 3 small families of snakes are peculiar. There are also 3 peculiar families of fresh-water fishes.