Page:EB1911 - Volume 28.djvu/1037

Rh appear to be the west Indian solenodons. The bats are likewise different from those of the mainland; a notable feature being the occurrence of flying-foxes of the Asiatic and Australian genus Pteropus. Of the countless rodents of Africa, all are wanting; while the only members of that group inhabiting the island are certain rat-like animals collectively constituting the family Nesomyidae.

The birds are scarcely less remarkable than the mammals, such common Ethiopian types as the ostrich, secretary-bird, honey-guides {Indicator), wood-hoopoes, ground-hornbills, ox-peckers, barbets and glossy starlings being entirely unknown. On the other hand, the Malagasy region, inclusive of the Mascarene islands, comprises quite a number of distinctive bird-genera, such as Mesites, Tylas, Artamia, Calicalicus, Euryceros, Philepitta, Atelornis and Leptosomus; the first of these representing a peculiar family of game-birds, while the last, including only the kirombo, forms a subfamily of rollers (Coraciidae). In the Pleistocene the ostrich group was represented by various species of Aepyornis, probably the original of the legendary roc; while within historic times Mauritius and Reunion were the respective homes of the two species of dodo (Didus), and Rodriguez was inhabited by the solitaire (Pezophaps), the three constituting the family Dididae. The guinea-fowls, on the contrary, form a group common to the Ethiopian and Malagasy regions and are unknown elsewhere.

Many of the features of the reptilian fauna are alluded to under the headings of Neogaea and the Ethiopian region. Among lizards, the absence of Agamidae, Veranidae, Lacertidae, Amphisbaenidae and Anguidae is very remarkable, since all these except the last are Ethiopian. In addition, Madagascar possesses, apart from the cosmopolitan skinks and geckos, only Gerrhosauridae, Zonuridae and chameleons (Chamaeleontidae), which are essentially African groups. Affinity with Neogaea is indicated by the presence of a few iguanas, of snakes of the boa group (especially the genus Boa), and of Podocnemis among the tortoises. The other pleurodiran tortoises are, however, of an Ethiopian type. The same may perhaps be said with regard to the giant land-tortoises of the genus Testudo, which in Pleistocene or modern times were spread over all the islands of the region, while they existed in Africa in the Eocene, as well as in India in the Pliocene. The spider-tortoise (Pyxis) is a peculiar cryptodiran Malagasy genus. In the matter of batrachians the Malagasy region lacks both coecilians (Apoda) and tongueless toads (Aglossa), while it has abundance of true frogs (Raninae), among them the Oriental genus Rhacophorus. Of fishes, the peculiar Ethiopian types are absent from the present region, although the community of the Cichlidae to Neogaea and the Ethiopian, Malagasy and Oriental regions is noteworthy. It may be added that Madagascar differs from Ethiopia in possessing one fresh-water cray-fish, the representative of a genus by itself.

The radical distinctness of the Malagasy fauna is thus demonstrated from all sides. That the island has been separated from Ethiopia during the greater portion of the Tertiary period is self-evident. The interpretation of its relationships with other regions is, however, exceedingly difficult. It is generally considered that the Comoro and Seychelle groups mark the line of a former connexion between Madagascar and India, and also with South Africa; but it is evident that this line must have been closed to the passage of mammals since a very remote date, as is exemplified by the fact that the lorises of Ceylon and southern India are quite distinct from the Malagasy lemurs, and much nearer to the African pottos. Whether the occurrence of South American types of reptiles (boas, Podocnemis, and iguanas) in Madagascar and not in Africa can be held to indicate a late connexion with Neogaea by way of the Pacific, cannot yet be decided. The occurrence of iguanas in Fiji is, however, as noteworthy as is the community of Miolania to Patagonia and Queensland. Moreover, Polynesia is evidently a subsiding area. In the opinion of Captain F. Hutton the land-shells of the genus Endodonta, which range all through Polynesia, New Zealand, eastern Australia, New Guinea and the Philippines, with an outlier in Ceylon, afford the best evidence in favour of a Polynesian continent, the Singhalese outlier pointing to the conclusion that this group of molluscs originally came from the north. The molluscan evidence will not, however, explain the South American connexion.

Zoological evidence of the latter connexion, by way of Antarctica, is afforded by the earthworms of the family Acanthodrilidae, which are unknown north of the equator, although their occurrence in Madagascar may point to a northern origin. Additional evidence of a connexion with Patagonia is afforded by the occurrence in the Tertiary strata of South America and New Zealand of a number of shallow-water marine invertebrates. Further, the occurrence of these forms in older strata in South America than in New Zealand suggests that the migration took place from the former to the latter area.

The relatively small and wholly tropical or subtropical Oriental region was originally taken to include the Punjab; but in a memoir, of which an abstract appeared in the Proceedings of the Royal Society of London for 1900 (vol. Ixvii. p. 484), Dr Stanford came

to the conclusion that the Punjab differs so remarkably in its fauna from the rest of India that it cannot be included in the Oriental region, and must be assigned to the Mediterranean oriental transitional region. To the latter belongs also the Himalayan area above the forests, as does Tibet. India proper, together with Ceylon, is regarded as a single subdivision of the Oriental region, under the title of Cisgangetic, while the Himalaya and Burma form a second subregion, the Transgangetic, which also includes southern China, Tonquin, Siam and Cambodia. A third subregion, the Malayan, includes southern Tenasserim, the Malay Peninsula, and the Malay Archipelago exclusive of Celebes. In the map in the present article the last-named island is included in the present region, although, as stated, it is by preference referred to an Austro-Malay transitional region. Wallace drew the main line dividing the Oriental from the Australian region between the islands of Bali and Lombok, and between Borneo and Celebes: "The strait [between Bali and Lombok] is here fifteen miles wide, so that we may pass in two hours from one great division of the earth to another, differing as essentially in their animal life as Europe does from America. If we travel from Java or Borneo to Celebes or the Moluccas, the difference is still more striking." The hydrographic results obtained by the Dutch Siboga Expedition show, however, that although there exists a line of great depth separating the two areas, this line on no point corresponds to "Wallace's line." On the contrary, it passes east of Timor and through the Banda and Molucca seas, separating Sula from Buru, Obi and Halmaheira. For this line which replaces "Wallace's line," Dr A. Pelseneer has proposed the name of "Weber's line." It is this "Weber's line" which marks the real division between the Arctogaeic and the Notogaeic faunas, although it has been convenient to make Celebes the centre of an intermediate transitional region.

The Oriental region agrees with the Ethiopian in being inhabited by elephants, rhinoceroses, buffaloes, several large representatives of the Felidae (among which the lion, leopard and hunting-leopard are common to the two areas), and numerous civets and mungooses. The elephant and the three species of rhinoceros are, however, subgenerically distinct from their Ethiopian relatives, and the buffaloes are also widely different from those of Africa. Wild cattle (of the subgenus Bibos), as represented by the gaur and the bantin, are peculiar to this region; and, with the exception of gazelles, antelopes are poorly represented, although the three genera Antilope (blackbuck), Tetroceros (chousingha), and Tragocamelus (nilgai) are restricted to the area. Southern India has one tahr (Hemitragus) in its mountains, and this genus also occurs in the Himalaya, where serows (Nemorhaedus) and gorals (Urotragus)—goat-like antelopes ranging through the Malay countries—are likewise met with. Deer (Cervidae) are abundant, and include three peculiar subgenera of Cervus, namely Rusa, Hyelaphus and Rucervus, to the exclusion of the typical red deer group. The typical Tragulus represents the chevrotains; and the pigs, unlike those of Ethiopia, belong to the typical section of Sus. In addition to Neogaea, the Malay subregion is now the sole habitat of tapirs (Tapiridae). A notable distinction from Ethiopia is the presence of bears, which are, however, distinct from the typical Ursus arctus group of the north. Borneo and Sumatra form the home of the orang-utan (Simia), the sole Oriental representative of the Simiidae, while the gibbons (Hylobatidae), which range as far west as the eastern Himalaya, are restricted to the region. The monkeys are all generically distinct from those of Ethiopia. The tarsier represents a family (Tarsiidae) by itself; and the lorises a subfamily (Nycticebinae) peculiar to the forest-tracts. Fruit-bats of the genera Pteropus, Rousettus and Cynopterus help to distinguish the region from Ethiopia; while among the Insectivora the tupais, or tree-shrews (Tupaiidae), .with three genera, and the rat-shrews (Gymnurinae), also with three generic modifications, are likewise solely Oriental. The cobegos, or flying-lemurs (Galeopithecus), represent an ordinal group (Dermoptera) peculiar to this region; while there are several distinctive genera of rodents, especially in the mountains of the Philippines, where some approximate closely to the Australian type represented by Hydromys.

Pangolins, of a type different from those of Ethiopia, alone represent the Edentata. A striking feature of the mammalian fauna of the region is the presence of so many peculiar and probably archaic types in the Malay subregion, and the affinity of the fauna of this area to that of western Africa. Both districts may be said to be highly conservative in the matter of their faunas.

The birds are extremely abundant, and include a number of peculiar genera to which detailed reference is impossible. There is no representative of the ostrich group; and the place of guinea-fowls is taken by pea-fowl (Pavo) and argus-pheasants (Argusiana), while francolins (Francolinus) abound. Attention may be directed to the abundance of pheasants, pigeons, king-fishers, sunbirds, flycatchers and starlings. The babblers (Timeliidae) are especially numerous, the group allied to the hill-robin (Liothrix) being peculiar to the region, as are also the green bulbuls (Chloropsis). True