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former arms stretched upwards and embraced New Zealand, Eastern Australia, Tasmania, Madagascar, the Mascarene Islands, and part of South America. The grounds for this bold assumption, which, although by no means new, has not been previously developed to so great an extent, rest chiefly on the finding of the remains of a large ocydromine rail in the Chatham Islands, allied to the now extinct Aphanapteryx of Mauritius, and the fossil bones of a large coot (Fulica) allied to F. newtoni of the same island. Other evidence adduced is that of the occurrence of the Ratite, or Struthious birds, in New Zealand, Australia, Madagascar, and Patagonia. But the distribution of Struthious birds is probably to be explained much in the same way as the distribution of other archaic forms, such as the lemurs and tapirs. They are remnants of what were formerly widely spread groups. That this is likely to be the case is shown by the recent discovery, in other parts of the world (such as the Sewaliks of India, and the Eocenes of England and France) of the remains of other extinct Ratite birds.
Another piece of evidence brought forward by Dr. Forbes is the occurrence of Didunculus in the Samoan group, and of the Dodo (Didus), to which Didunculus was once supposed to be nearly related, in Mauritius. But it is now allowed that Didunculus has little near affinity to the Dodo, and that it is in fact a mere strongly modified member of the family Columbida.
Mauritius, as a matter of fact, is in every way a typical oceanic island, and there seems to be little evidence, either physical or zoological, of its having been ever connected with any other land.
SECTION X.-THE POLYNESIAN SUB-REGION
The Polynesian Sub-region includes all the numerous and scattered island groups of the Pacific, from the Ladrones and Carolines in the west to the Marquesas in the east, with the exception of the Sandwich Islands, which, owing to their many peculiarities, must be kept apart as a separate Sub-region.
There is very little to be said concerning the Polynesian Sub-region so far as mammals are concerned. As is always the case with oceanic islands-that is, islands that do not seem to have ever been directly connected with any of the great land-masses of the globe-the Mammal-fauna of Polynesia is practically non-existent, the only exception being a certain number of Bats, which are creatures able to traverse the intermediate sea-areas, and so more resembling birds than ordinary mammals in their distribution.
There are, however, besides the Bats, three or four species of the cosmopolitan genus Mus (Mice and Rats), recorded to occur in Polynesia, whether truly indigenous or the modified descendants of introduced species it is impossible to say.
Of the eleven species of Bats which have been registered as Polynesian, eight are peculiar to the Sub-region, two extend into Papua, and one ranges even as far as the Oriental Region.
But, looking to the extreme poverty of the Mammalfauna, it is evident that, to ascertain the general character of the Sub-region, we must turn to the Birds. These, as shown by the excellent summary of Polynesian Ornithology
recently compiled by Mr. Wiglesworth (15), are, considering the number of islands, not numerous, but on the whole show distinctly Australian affinities.
SECTION XI. THE HAWAIIAN SUB-REGION
The Hawaiian Sub-region includes only the Sandwich Islands. This group of islands is situated in the northern part of the Pacific Ocean, and is very isolated, not only from the great land-masses of Asia and America, from which it is separated by a very deep ocean more than 2000 miles across, but also from the other larger groups of the Polynesian islands such as Samoa and the Marquesas, from which it is parted by nearly the same distance.
The larger islands composing the group are seven in number, all of purely volcanic origin.
As would be naturally expected, there are no indigenous land-mammals in the Hawaiian Sub-region, but a single species of bat (Atalapha semota) occurs there. This bat belongs to a genus found in America, and has, no doubt, reached the Sandwich Islands from that continent. The birds, however, to which we must turn for a moment in ́order to gain some idea as to the composition of the Hawaiian fauna, show extreme specialisation. The greater number, not only of the species but even of the genera of this Sub-region, are peculiar and wholly restricted to these islands. It is, of course, among the smaller landbirds (Passeres) that this individuality is most marked; but even in the other groups, where the distribution is generally wider, the Hawaiian birds are, in many cases, local. We shall, however, be able to form a better general
idea upon this subject when Mr. Scott Wilson's new work on the Hawaiian Avifauna (16), now in process of issue, has been brought to a conclusion.
As is the case with the Birds, so with the Landshells, which have been carefully studied by the Rev. J. T. Gulick, a wonderful specialisation is found in the Hawaiian fauna.
There are, therefore, ample grounds for making a separate Sub-region for this remote island group, notwithstanding its small size and the complete absence of mammalian life.
LIST OF THE PRINCIPAL AUTHORITIES REFERRED TO IN
(1) AMEGHINO, F.-"Revista Argentina de Historia Natural.' Tomo 1 (1891).
(2) COLLETT, R.-"On some apparently New Marsupials from Queensland." P. Z. S., 1884, p. 381, pls. xxix.-xxxii.
(3) DOBSON, G. E.-"Catalogue of the Chiroptera in the Collection of the British Museum" (1878).
(4) FORBES, H. O.—“The Chatham Islands: their Relation to a Former Continent." R. Geogr. Soc. Suppl. Papers, III., pt. 4 (1893).
(5) GOULD, J.-"The Mammals of Australia." 3 vols. London (1845-63).
(6) LUMHOLTZ, C.-"Notes upon some Mammals recently discovered in Queensland." P. Z. S., 1884, p. 406.
(7) OGILBY, J. D.-" Catalogue of Australian Mammals." Sydney (1892).
(8) PETERS, W., and DORIA, G.-" Enumerazione dei Mammiferi raccolti da O. Beccari, L. M. d'Albertis ed A. A. Bruijn nella Nuova Guinea propriamenta detta." Ann. Mus. Civ. Stor. Nat. Genov., XVI., p. 665, pls. v.-xviii. (1881).
(9) STIRLING, E. C.-" Description of a New Genus and Species of Marsupialia, Notoryctes typhlops." Trans. R. Soc. S. Austr., XIV., p. 154, pls. ii.-ix. (1891). See also op. cit., p. 283, pl. xii.
(10) THOMAS, O.-" On the Bats collected by Mr. C. M. Woodford in the Solomon Islands." P. Z. S., 1887, p. 320, pls. xxv. and xxvi. "The Mammals of the Solomon Islands, based on the