of land and sea by which the phenomena of animal distribution in the Pacific have been brought about.

Reptiles of the Polynesian Sub-region.-The researches of Mr. Darwin on Coral Islands, proved, that large areas in the Pacific Ocean have been recently subsiding; but the peculiar forms of life which they present, no less clearly indicate the former existence of some extensive lands. The total absence of Mammalia, however, shows either that these lands never formed part of the Australian or Papuan continents, or if they did, that they have been since subjected to such an amount of subsidence as to exterminate most of their higher terrestrial forms of life. It is a remarkable circumstance, that although Mammalia (except bats) are wanting, there are a considerable number of reptiles ranging over the whole sub-region. Lizards are the most numerous, five families and fourteen genera being represented, as follows:

The first five are wide-spread genera, represented mostly by peculiar species; but sometimes the species themselves have a wide range, as in the case of Ablepharus pacilopleurus, which (according to Dr. Günther) is found in Timor, Australia, New Caledonia, Savage Island (one of the Samoa group), and the Sandwich Islands! Gehyra and Heteronota are Australian genera; while Lophura has reached the Pelew Islands from the Moluccas. The remainder (printed in italics), are peculiar genera; Brachylophus being especially interesting as an example of an

otherwise peculiar American family, occurring so far across the Pacific.

Snakes are much less abundant, only four genera being represented, one of them marine. They are, Anoplodipsas, a peculiar genus of Amblycephalidæ from New Caledonia; Enygrus, a genus of Pythonidæ from the Fiji Islands; Ogmodon, a peculiar genus of Elapidæ, also from the Fiji Islands, but ranging to Papua and the Moluccas; and Platurus, a wide-spread genus of sea-snakes (Hydrophidae). In the more remote Sandwich and Society Islands there appear to be no snakes. This accords with our conclusion that lizards have some special means of dispersal over the ocean which detracts from their value as indicating zoo-geographical affinities; which is further proved by the marvellous range of a single species (referred to above) from Australia to the Sandwich Islands.

A species of Hyla is said to inhabit the New Hebrides, and several species of Platymantis (tree-frogs) are found in the Fiji Islands; but otherwise the Amphibians appear to be unrepresented in the sub-region, though they will most likely be found in so large an island as New Caledonia.

From the foregoing sketch, it appears, that although the reptiles present some special features, they agree on the whole with the birds, in showing, that the islands of Polynesia all belong to the Australian region, and that in the Fiji Islands is to be found the fullest development of their peculiar fauna.

IV. New Zealand Sub-region.

The islands of New Zealand are more completely oceanic than any other extensive tract of land, being about 1,200 miles from Australia and nearly the same distance from New Caledonia and the Friendly Isles. There are, however, several islets scattered around, whose productions show that they belong to the same sub-region;-the principal being, Norfolk Island, Lord Howe's Island, and the Kermadec Isles, on the north; Chatham Island on the east; the Auckland and Macquarie Isles on the south; and if these were once joined to

New Zealand, there would have been formed an island-continent not much inferior in extent to Australia itself.

New Zealand is wholly situated in the warmer portion of the Temperate zone, and enjoys an exceptionally mild and equable climate. It has abundant moisture, and thus comes within the limits of the South-Temperate forest zone; and this leads to its productions often resembling those of the tropical, but moist and wooded, islands of the Pacific, rather than those of the temperate, but arid and scantily wooded plains of Australia. The two islands of New Zealand are about the same extent (approximately) as the British Isles, but the difference in the general features of their natural history is very great. There are, in the former, no mammalia, less than half as many birds, very few reptiles and fresh-water fishes, and an excessive and most unintelligible poverty of insects; yet, considering the situation of the islands and their evidently long-continued isolation, the wonder rather is that their fauna is so varied and interesting as it is found to be. Our knowledge of this fauna, though no doubt far from complete, is sufficiently ample; and it will be well to give a pretty full account of it, in order to see what conclusions may be drawn as to its origin.

Mammalia. The only mammals positively known as indigenous to New Zealand are two bats, both peculiar to it,-Scotophilus tuberculatus and Mystacina tuberculata. The former is allied to Australian forms; the latter is more interesting, as being a peculiar genus of the family Noctilionidæ, which does not exist in Australia; and in having decided resemblances to the Phyllostomidae of South America, so that it may almost be considered to be a connecting link between the two families. A forest rat is said to have once abounded on the islands, and to have been used for food by the natives; but there is much doubt as to what it really was, and whether it was not an introduced species. The seals are wide-spread antarctic forms which have no geographical significance.

Birds. About 145 species of birds are natives of New Zealand, of which 88 are waders or aquatics, leaving 57 land-birds belong

ing to 34 genera. Of this latter number, 16, or nearly half, are peculiar; and there are also 5 peculiar genera of waders and aquatic birds, making 21 in all. Of the remaining genera of land-birds, four are cosmopolite or of very wide range, while the remainder are characteristic of the Australian region. The following is a list of the Australian genera found in New Zealand: Sphenæacus, Gerygone, Orthonyx (Sylviida); Graucalus (Campephagidae); Rhipidura (Muscicapidae); Anthochara (Meliphagidae); Zosterops (Dicæida); Cyanoramphus (Platycercida); Carpophaga (Columbida); Hieracidea (Falconida); Tribonyx (Rallidae). Besides these there are several genera of wide range, as follows:-Anthus (Motacillida); Hirundo (Hirundinida); Chrysococcyx, Eudynamis (Cuculidæ); Halcyon (Alcedinida); Coturnix (Tetraonida); Circus (Falconida); Athene (Strigida).

Most of the above genera are represented by peculiar New Zealand species, but in several cases the species are identical with those of Australia, as in the following: Anthochera carunculata, Zosterops lateralis, Hirundo nigricans, and Chrysococcyx lucidus; also one-Eudynamis taitensis—which is Polynesian. We now come to the genera peculiar to New Zealand, which are of especial interest:

LIST OF GENERA OF BIRDS PECULIAR TO NEW ZEALAND,

We have thus a wonderful amount of speciality; yet the affinities of the fauna, whenever they can be traced, are with Australia or Polynesia. Nine genera of New Zealand birds are characteristically Australian, and the eight genera of wide range are Australian also. Of the peculiar genera, 7 or 8 are undoubtedly allied to Australian groups. There are also four Australian and one Polynesian species. Even the peculiar family, Nestoridæ, is allied to the Australian Trichoglossidae. We have therefore every gradation of similarity to the Australian fauna, from identical species, through identical genera, and allied genera, to distinct but allied families; clearly indicating very long continued yet rare immigations from Australia or Polynesia; immigrations which are continued down to our day. For resident ornithologists believe, that the Zosterops lateralis has found its way to New Zealand within the last few years, and that the two cuckoos now migrate annually, the one from Australia, the other from some