cosmopolitian Mus, or true Mouse, numbers no less than eighteen species in Australia. The habits of the Watervoles of Europe are assumed by the species of the genus Hydromys, which are modified for aquatic life, while the species of Hapalotis are found chiefly in the dry sandy scrubs.

The Bats, with one exception, all belong to genera of considerably wide distribution, and the number of species known to inhabit Australia is not very great. Thirty only are described in Dr. Dobson's catalogue of the Bats as Australian. Pteropus, the great genus of Fruit-eating Bats, is represented by a few species; so too are the widespread insectivorous genera Vesperugo and Miniopterus. One species of the former genus, the Southern Pipistrelle (V. abramus), is found almost throughout the Old World, from Sweden to North Australia.

SECTION V.-ANALYSIS OF THE AUSTRAL

MAMMAL-FAUNA

The full list of the Mammalian Fauna of the Austral Sub-region contains the names of about 169 species, referable to fifty-nine genera. Of these genera twenty-nine, just half, are not found outside the Austral Sub-region, the greater number of them (twenty-five) being Marsupials; they include, however, three genera of Mice (Xeromys, Hapalotis, and Mastacomys) and one peculiar Bat (Rhinonycteris). Thirteen genera are confined to the Australian Region, that is, are found in the Papuan Subregion as well as in the Austral Sub-region; of these, again, the majority are Marsupials, besides which there

C

are

are two genera of Rodents (Hydromys and Uromys), and one Bat (Nyctophilus). Seventeen genera which found in Australia extend beyond the limits of the Region, to the Oriental, and in some cases range even into the Ethiopian and Palearctic Regions. Of these the greater number (fourteen) are Bats; one is a Marsupial (Phalanger), of which two species occur in Celebes; another is the widely spread genus Mus, which is found throughout the Old World; and the last is a Carnivore (Canis), of which the Australian representative is the Dingo. Canis is spread over the whole of the rest of the world, both Old and New.

Turning now to the distribution of the genera within the continent of Australia itself, it will be found that out of forty-three genera (of Monotremes, Marsupials, and Rodents), twenty are fairly represented throughout the whole area, thirteen are confined to the east (several of these ranging north into New Guinea), seven are restricted to the western and central parts of the continent (these latter are chiefly desert forms such as Perogale, Choropus, and Notoryctes), and the three remaining genera are found only in Tasmania. These are Thylacinus,

Dasyurus, and Mastacomys.

If now we reconsider the list, counting only Monotremes, Marsupials, and Rodents, it will be found that out of 130 species, thirty-five range from west to east to greater or less extent; forty-nine are confined to the eastern part of Australia, in many cases extending to Tasmania; and thirty-six are peculiar to Western Australia, while ten species out of the whole Mammal-fauna are peculiar to Tasmania.

SECTION VI.-PAST HISTORY OF THE MAMMAL

FAUNA OF THE AUSTRAL SUB-REGION

The past history of the Australian mammals is still very obscure; the only remains of extinct species yet discovered have been found in certain bone-caves and in surface-deposits generally attributed to the Pleistocene Epoch.

Putting aside the Dingo, all the Pleistocene mammals of Australia belong to the Monotremes or to the Marsupials, and, with two exceptions, can be accommodated in still existing families. These exceptions are Nototherium and Diprotodon, the latter of which was a very large animal, equalling a Rhinoceros in bulk, but both of them were probably allied to the existing Kangaroos.

Recently a deposit containing bones of these and other large Marsupials has been found in a dry salt lagoon, called Lake Mulligan, in South Australia, and when these remains have been worked out, a great deal more information as regards this pliocene or pleistocene fauna may be expected. As in South America, these extinct animals appear in many cases to have attained a size far surpassing that of their degenerate descendants.

None of the remains hitherto found in Australia throw much light on the origin of its remarkable fauna. But quite recently evidence of an extensive mammalian fauna has been discovered in certain beds, of probably Upper Eocene age, in Santa Cruz, Patagonia. In addition to a number of other forms, this series contains the remains of many Marsupials, and though the most prominent of them belong to the Didelphyida—the Marsupial

family now confined to America, and apparently distributed over the whole northern hemisphere during Tertiary times, but not found in Australia-a certain number of them show an Australian stamp. Some of them have even been relegated by Ameghino (1), to whose researches our knowledge of the Santa Cruzian fauna is mainly due, to the existing Australian family Dasyurida.

If, on further investigation, these references shall be found to be correct, the inference would seem to be that in very remote times-probably in the early Tertiary or the late Secondary Period-there has been some sort of landconnection between South America and Australia. In such case there would be no necessity to suppose that Australia was ever directly connected with the rest of the Old World at all, none of the peculiar forms of Australian Marsupials having yet been detected in any other part of the globe.

Besides the common possession of Marsupials, many other resemblances between the faunas of Australia and South America have been pointed out to occur among the Birds and Amphibians, and especially among the Fishes. Two families of freshwater fishes (Galaxiidæ and Haplochitonida) are found exclusively in these two Regions, and are not known to occur elsewhere.

Apart from speculation, however, there is no question that Australia has been isolated from all the other continents since the end of the Secondary, or at least since the beginning of the Tertiary Period of geological time.

SECTION VII.-THE PAPUAN SUB-REGION

In contrast to Australia, the great island of New Guinea, or Papua, is traversed throughout by mountains of high altitude. The rivers rising in these ranges, aided by the suns of the tropics, produce a luxuriant vegetation, and such a country as we should suppose would be especially favourable to mammal-life. Yet mammals are by no means abundant in New Guinea and in the adjacent islands which constitute the Papuan Sub-region. As is the case in Australia, the greater number of the indigenous animals of New Guinea and the neighbouring islands consist of Monotremes, Marsupials, and Rodents, together with a certain number of the cosmopolitan order of Bats (8, 10, 11).

Of the Monotremes, two species have been met with in New Guinea, both of them belonging to the family of Echidnas above referred to. Of these one species, only at present known from the south of New Guinea, is but a slightly modified form of the small Australian Echidna. But in the mountains, in various parts of New Guinea, has been lately discovered a larger representative of the same family (Proechidna), which, moreover, differs from the typical form in having only three toes on its fore limbs, and in other particulars (Fig. 6, p. 38).

The Papuan Marsupials, as yet discovered, are about thirty-three in number, and embrace representatives of the Dasyures, Bandicoots, Phalangers, and Kangaroos, which are also characteristic families of the Australian mammalfauna.

There are only two genera of Marsupials peculiar to the