possess, for passing over a considerable width of sea. We must conclude, therefore, that these islands do not owe their existing fauna to an actual union with the mainland; but it is probable that they may have been formerly more extensive, and have then been less distant from the continent than at the present time.

The Nicobar Islands, usually associated with the Andamans, are less known, but present somewhat similar phenomena. They are, however, more Malayan in their fauna, and seem properly to belong to the Indo-Malay sub-region.

Formosa. This island has been carefully examined by Mr. Swinhoe, who found 144 species of birds, of which 34 are peculiar. There is one peculiar genus, but the rest are all Indo-Chinese, though some of the species are more allied to Malayan than to Chinese or Himalayan forms. About 30 species of mammalia were found in Formosa, of which 11 are peculiar species, the rest being either Chinese or Himalayan. The peculiar species belong to the genera Talpa, Helictis, Sciuropterus, Pteromys, Mus, Sus, Cervus, and Capricornis. A few lizards and snakes of continental species have also been found. These facts clearly indicate the former connection of Formosa with China and Malaya, a connection which is rendered the more probable by the shallow sea which still connects all these countries.

Hainan.-The island of Hainan, on the south coast of China, is not so well known in proportion, though Mr. Swinhoe collected 172 species of birds, of which 130 were land-birds. Of these about 20 were peculiar species; the remainder being either Chinese, Himalayan, or Indo-Malayan. Mr. Swinhoe also obtained 24 species of mammalia, all being Chinese, Himalayan, or Indo-Malayan species except a hare, which is peculiar. This assemblage of animals would imply that Hainan, as might be anticipated from its position, has been more recently separated from the continent than the more distant island of Formosa.

IV. Indo-Malaya, or the Malayan Sub-region. This sub-region, which is almost wholly insular (including only the Malayan peninsula on the continent of Asia), is equal, if

not superior, in the variety and beauty of its productions, to that which we have just been considering. Like Indo-China, it is a region of forests, but it is more exclusively tropical; and it is therefore deficient in many of those curious forms of the temperate zone of the Himalayas, which seem to have been developed from Palearctic rather than from Oriental types. Here alone, in the Oriental region, are found the most typical equatorial forms of life-organisms adapted to a climate characterised by uniform but not excessive heat, abundant moisture, and no marked departure from the average meteorological state, throughout the year. These favourable conditions of life only occur in three widely separated districts of the globe-the Malay archipelago, Western Africa, and equatorial South America. Hence perhaps it is, that the tapir and the trogons of Malacca should so closely resemble those of South America; and that the great anthropoid apes and crested hornbills of Western Africa, should find their nearest allies in Borneo and Sumatra.

Although the islands which go to form this sub-region are often separated from each other by a considerable, expanse of sea, yet their productions in general offer no greater differences than those of portions of the Indo-Chinese subregion separated by an equal extent of dry land. The explanation is easy, however, when we find that the sea which separates them is a very shallow one, so shallow that an elevation of only 300 feet would unite Sumatra, Java, and Borneo into one great South-eastern prolongation of the Asiatic continent. As we know that our own country has been elevated and depressed to a greater amount than this, at least twice in recent geological times, we can have no difficulty in admitting similar changes of level in the Malay archipelago, where the subterranean forces which bring about such changes are still at work, as manifested by the great chain of active volcanoes in Sumatra and Java. Proofs of somewhat earlier changes of level are to be seen in the Tertiary coal formations of Borneo, which demonstrate a succession of elevations and subsidences, with as much certainty as if we had historical record of them.

It is not necessary to suppose, nor is it probable, that all these

great islands were recently united to the continent, and that their separation took place by one general subsidence of the whole. It is more consonant with what we know of such matters, that the elevations and depressions were partial, varying in their points of action and often recurring; sometimes extending one part of an island, sometimes another; now joining an island to the main land, now bringing two islands into closer proximity. There is reason to believe that sometimes an intervening island has sunk or receded and allowed others which it before separated to effect a partial union independently of it. If we recognise the probability that such varied and often-renewed changes of level have occurred, we shall be better able to understand how certain anomalies of distribution in these islands may have been brought about. We will now endeavour to sketch the general features of the zoology of this interesting district, and then proceed to discuss some of the relations of the islands to each other.

Mammalia.-We have seen that the Indo-Chinese sub-region possesses 13 species of mammalia in common with the IndoMalay sub-region, and 4 others peculiar to itself, besides one Ethiopian and several Oriental and Palearctic forms of wide range. Of this latter class the Malay islands have comparatively few, but they possess no less than 14 peculiar genera, vizSimia, Siamanga, Tarsius, Galeopithecus, Hylomys, Ptilocerus, Gymnura, Cynogale, Hemigalea, Arctogale, Barangia, Mydaus, Helarctos, and Tapirus. The islands also possess tigers, deer, wild pigs, wild cattle, elephants, the scaly ant-eater, and most of the usual Oriental genera; so that they are on the whole fully as rich as, if not richer than, any part of Asia; a fact very unusual in island faunas, and very suggestive of their really continental nature.

Plate VIII. Scene in Borneo with Characteristic Malayan Quadrupeds.-The Malayan fauna is so rich and peculiar that we devote two plates to illustrate it. We have here a group of mammalia, such as might be seen together in the vast forests of Borneo. In the foreground we have the beautiful deer-like Chevrotain (Tragulus javanicus). These are delicate little