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four genera, of which sixteen, or nearly half, are not known elsewhere. There are also five peculiar genera of waders and aquatic birds in New Zealand, making twenty-one indigenous genera in all. Among its few reptiles, also, New Zealand numbers the very remarkable Tuatera (Sphenodon punctatus), which, though externally resembling a lizard, differs from all other lacertians in so inany points of its skeleton and internal structure that it is usually considered to belong to a separate and distinct order of reptiles. The nearest allies of this form are found among three extinct families which make up the order Rhynchocephalia. Remains of these families occur in beds of Permian age in Germany, in the Keuper of Elgin (Scotland), and in the (probably contemporaneous) Gondwana beds of India, as likewise in the lower Eocenes of North America and Northern Europe.
All these facts indicate a great amount of individualism in the Maorian Sub-region. But on the whole they betray an affinity to the tropical parts of Australia and to the Papuan Sub-region rather than to the temperate portion of Australia, to which New Zealand is now nearest in point of actual distance. This connection is further confirmed by the soundings of the seas round the islands, which show that, although on the west, south, and east deep water extends all round, a long submerged bank, with a depth of less than 1000 fathoms, stretches along to the north-west, and connects the shallow waters round Australia with those round New Zealand.
It is probable that the land connection between the two areas, if it ever actually existed, took place somewhere along this line.
As already mentioned in the first chapter of this volume, some writers on Geographical Distribution, especially Professor Huxley and Professor Newton, are inclined to give to New Zealand and its islands the rank of an independent Region among the primary divisions of the globe. There is, no doubt, as has just been shown, a good deal to be said for this proposal; but, on the other hand, there are even stronger reasons for retaining New Zealand as a Sub-region of the Australian Region. In the first place, we are here dealing with Mammals alone, and it seems rather absurd to assign the value of a primary Region to a group of small islands characterised by the almost entire absence of that class of animals with which we are most concerned. In the second place, looking at Regions from a more general point of view, there is a great practical convenience (as Mr. Wallace has pointed out) in keeping the more or less equal divisions of the globe as primary divisions. It seems, therefore, to be quite unnecessary to elevate so small a portion of the world into a Primary Region. Other small insular areas might, with some justice, put forward nearly similar claims. In the third place, although New Zealand possesses no indigenous terrestrial Mammals, yet the fauna, such as it is, shows an unmistakable affinity of various degrees to that of Australia, and more especially to the tropical part of that continent. It is, indeed, probable that the whole of the fauna of New Zealand has been originally derived from that source, although in the greater number of cases it has undergone considerable modification.
Dr. H. O. Forbes (4) has lately published a speculative article on the former existence of a (now mostly submerged) southern continent, the remains of which are represented by the land round the South Pole, while
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 Ratitæ, 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 Columbidæ.
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