PALAEOTROPICAL REGION  .—Muchcanbe said in favour of combining the mostly tropical portion of the

great mass of land of the Old World (excluding, of course, Austrogaea or the Australian region) into one region, for which Oscar Drude's well-chosen term " palaeotropical " has been adopted (cf . Bronn's Thierreich, System Part. p . 296, 1893) . This region naturally comprises the African and Indian areas, conformably to be called subregions . Both subregions possess, besides others, the following characteristic birds: Ratitae, viz . Struthio in Africa and Arabia, fossil also in the Sivalik Hills, and Aepyornithidae in Madagascar; Pittidae, Bucerotinae and Upupinae, of which Upupa itself in India, Madagascar and Africa; Coraciidae; Pycnonotidae or bulbuls; Trogonidae, of which the Asiatic genera are the less specialized in opposition to the Neotropical forms; Vulturidae; Leptoptilus, Anastomus and Ciconia among the storks; Pteroclidae; Treroninae among pigeons . Of other families which, however, extend their range more or less far into the Australian realm, may be mentioned Otididae, the bustards; Meropidae or bee-eaters; Muscicapidae or flycatchers; Sturnidae or starlings . The Ethiopian Subregion comprises the whole of Africa and Madagascar, except the Barbary States, but including Arabia; in the north-east the subregion melts into the Palaearctic between Palestine and the Persian Gulf . Some authors are inclined to extend its limits still farther to the eastwards, through Beluchistan and even beyond the Indus . So large a portion of the Ethiopian subregion lies between the tropics that no surprise need be expressed at the richness of its fauna relatively to that of the last two subregions we have considered . Between fifty and sixty so-called families of land birds alone are found within its limits, and of them at least nine are peculiar; the typical genera of which are Buphaga, Euryceros, Philepitta, Musophaga, Irrisor, Leptosoma, Colius, Serpentarius, Struthio, Aepyornis . It is singular that only the first three of them belong to the order Passeriformes, a proportion which is not maintained in any other tropical region .

The number of peculiar genera, besides those just mentioned, is too great for them to be named here; some of the most remarkable on the

continent are: Balaeniceps, the whale-headed heron; Balaearica, the crowned crane; Podica, finfoot; Numida and allied genera of guinea fowls . The natural division of the subregion is that into an African and a Madagascar province . Subdivision of the continental portion is beset with great difficulties, and none of the numerous attempts have proved long-lived . The forest-clad basin of the Congo, with the coastal districts of the bay of Guinea, seem to form one domain in opposition to the rest . The Malagasy province comprises, besides Madagascar, the Mascarene, Comoro and Seychelle islands . It may be safely deemed the most peculiar area of the earth's surface, while from the richness and multifariousness of its animal, and especially of its ornithic population, New Zealand cannot be compared with it . In A . Grandidier's magnificent Histoire physique, naturelle et Isolitique de Madagascar, vol. xii . (Paris, 1875-1884), are enumerated 238 species as belonging to the island, of which 129 are peculiar to it, and among those are no fewer than 35 peculiar genera . Euryceros of the 976 Oscines, and-Philepitta of the Clamatores, are remarkable enough to form the types of Passeriform families, and Mesites half-way between Galli and Gruiformes is of prime importance . The Passerine Falculia, with its recently extinguished allies Fregilupus and Necropsar of the Mascarenes; the Coraciine Brachypteracias, Atelornis and Geobiastes, are very abundant, while Heliodtilus is an owl belonging to that subfamily which is otherwise represented only by the widely-spread barn owl, Strix flammea . Lastly must be noted the extinct tall Ratite species of Aepyornis with its several fancy genera .

But, as

Newton charmingly puts it (Dict . Birds, p . 353), the avifauna of Madagascar is not entirely composed of such singularities as these . We have homely genera, even among the true Passeres, occurring there—such as Alauda, Acrocephalus, Motacilla and Pratincola, while the Cisticola madagascariensis is only distinguish-able from the well-known fan-tailed warbler, C. schoenicola of Europe, Africa and India by its rather darker coloration . But there are also species, though not Passerine, which are absolutely identical with those of Britain, the barn owl, common quail, pigmy rail, and little grebe or dabchick, all of them common and apparently resident in the island . Mauritius had the dodo (q.v.), Lophopsittacus and Aphanapteryx . Rodriguez had the solitaire, Necropsittacus and Necropsar . Bourbon or Reunion had Fregilupus . Some of the Malagasy avifauna is certainly ancient, aboriginal, and even points to India; other forms indicate clearly their African origin; while, lastly, such strikingly characteristic Indo-African birds as hornbills are unaccountably absent . The Oriental Subregion comprises all the countries and numerous islands between the Palaearctic and Australian areas; it possesses upwards of seventy families, of which, however, only one is peculiar, but this family, the Eurylaemidae or broadbills, is of great importance since it represents all the Subclamatores . Of the many characteristic birds may be mentioned Pycnonotidae or bulbuls, of which the Phyllornithinae are peculiar, Campephagidae or cuckoo-shrikes, Dicruridae or drongos, Nectariniidae or sunbirds; pheasants, together with Pavo and Gallus . Some of the similarities to the Ethiopian and the great differences from the Australian avifauna have already been pointed out .

Naturally no

line whatever can be drawn between the Oriental and the Palaearctic subregions, and many otherwise essentially Indo-Malayan families extend far into the Australian realm, far across Wallace's line, whilst the reverse takes place to a much more moderate extent . Certainly the Oriental area, in spite of its considerable size, cannot possibly claim the standing of a primary region . It is a continuation of the great Arctogaea into the tropics . Following H . J . Elwes we subdivide the whole subregion into a Himalo-Chinese, Indian and Malayan province . These divisions had the approval of W . T . Blanford, who proposed the terms Cis-and TransganFetic for the two first . The Himalo-Chinese or Transgangetic province shows the characteristics of its avifauna also far away to the eastward in Formosa, Hainan and Cochin China, and again in a lesser degree to the southward in the mountains of Malacca and Sumatra . Indo-China is especially rich in Eurylaemidae, China proper and the Himalayas in pheasants.[CLASSIFICATION The Indian or Cisgangetic province is the least rich of the three so far as peculiar genera are concerned . The Malayan province comprising the Malay islands, besides the Malay peninsula, and the very remarkable Philippines, possess an extraordinary number of peculiar and interesting genera .

The

influence of the Australian realm is indicated by a Megapode in Celebes, another in Borneo and Labuan, and a third in the Nicobar islands (which, however, like the Andamans, belong to the Indian province), but there are no cockatoos, these keeping strictly to the other side of Wallace's line, whence we started on this survey of the world's avifauna . D . CLASSIFICATION OF BIRDS Furbringer's great work, published in the year 1888 by the Natura Artis Magistra Society of Amsterdam, enabled Gadow not only to continue for the next five years the same lines of morphological research, but also further to investigate those questions which were still left in abeyance or seemed to require renewed study . The resulting " classification is based on the examination, mostly autoptic, of a far greater number of characters than any that had preceded it; moreover, they were chosen in a different way, discernment being exercised in sifting and weighing them, so as to determine, so far as possible, the relative value of each, according as that value may vary in different groups, and not to produce a mere mechanical ` key ' after the fashion become of late years so common " (Newton's Dictionary of Birds, Introduction, p . 103) . It is not the quantity but the quality of the anatomical and bionomic characters which determines their taxonomic value, and a few fundamental characters are better indications of the affinities of given groups of birds than a great number of agreements if these can be shown to be cases of isomorphism or heterophyletic, convergent analogy . Nature possesses three great educational or develop-mental schools—terrestrial, aquatic and aerial life . Each of these affords animal, vegetable or mixed diet . Animal diet implies the greatest variety with regard to locality and the modes of procuring the food . Each of these schools impresses its pupils, in the case of the birds, with its own stamp, but there are many combinations, since in the course of phyletic development many a group of birds has exchanged one school for another . Origin-ally terrestrial groups have taken to an entirely aquatic life, and vice versa; others, originally endowed with the power of flight, have become, or are transforming themselves into, absolutely cursorial forms; some members of one group live entirely on seeds, while others have become fierce fishers, and so forth . Only by the most careful inquiry into their history can their relationship or pedigree be unravelled .

A statement may now be given of Gadow's classification of birds, in which the extinct forms have been intercalated so far as possible .