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The Mammalia of New Guinea and the adjacent islands, yet discovered are only seventeen in number. Two of these are bats, one is a pig of a peculiar species (Sus papuensis), and the rest are all marsupials. The bats are, no doubt, much more numerous, but there is every reason to believe that whatever new land Mammalia may be discovered will belong to the marsupial order. One of these is a true kangaroo, very similar to some of the middle-sized kangaroos of Australia, and it is remarkable as being the first animal of the kind ever seen by Europeans. It inhabits Mysol and the Aru Islands (an allied species being found in New Guinea), and was seen and described by Le Brun in 1714, from living specimens at Batavia. A much more extraordinary creature is the tree-kangaroo, two species of which are known from New Guinea. These animals do not differ very strikingly in form from the terrestrial kangaroos, and appear to be but imperfectly adapted to an arboreal life, as they move rather slowly, and do not seem to have a very secure footing on the limb of a tree. The leaping power of the muscular tail is lost, and powerful claws have been acquired to assist in climbing, but in other respects the animal seems better adapted to walk on terra firma. This imperfect adaptation may be due to the fact of there being no carnivora in New Guinea, and no enemies of any kind from which these animals have to escape by rapid climbing. Four species of Cuscus, and the small flying opossum, also inhabit New Guinea; and there are five other smaller marsupials, one of which is the size of a rat, and takes its place by entering houses and devouring provisions.

The birds of New Guinea offer the greatest possible contrast to the Mammalia, since they are more numerous, more beautiful, and afford more new, curious, and elegant forms than those of any other island on the globe. Besides the birds of paradise, which we have already sufficiently considered, it possesses a number of other curious birds, which in the eyes of the ornithologist almost serves to distinguish it as one of the primary divisions of the earth. Among its thirty species of parrots are the Great Black Cockatoo, and the little rigid-tailed Nasiterna, the giant and the dwarf of the whole tribe. The bare-headed Dasyptilus is one of the most singu

lar parrots known; while the beautiful little long-tailed Charmosyna, and the great variety of gorgeously-colored lories, have no parallels elsewhere. Of pigeons it possesses about forty distinct species, among which are the magnificent crowned pigeons, now so well known in our aviaries, and pre-eminent both for size and beauty; the curious Trugon terrestris, which approaches the still more strange Didunculus of Samoa; and a new genus (Henicophaps), discovered by myself, which possesses a very long and powerful bill, quite unlike that of any other pigeon. Among its sixteen kingfishers, it possesses the curious hook-billed Macrorhina, and a red and blue Tanysiptera, the most beautiful of that beautiful genus. Among its perching birds are the fine genus of crow-like starlings, with brilliant plumage (Manucodia); the curious pale-colored crow (Gymnocorvus senex); the abnormal red and black flycatcher (Peltops blainvillii); the curious little boat-billed flycatchers (Machærirhynchus); and the elegant blue flycatcherwrens (Todopsis).

The naturalist will obtain a clearer idea of the variety and interest of the productions of this country by the statement that its land birds belong to 108 genera, of which 29 are exclusively characteristic of it; while 35 belong to that limited area which includes the Moluccas and North Australia, and whose species of these genera have been entirely derived from New Guinea. About one-half of the New Guinea genera are found also in Australia, about one-third in India and the IndoMalay islands.

A very curious fact, not hitherto sufficiently noticed, is the appearance of a pure Malay element in the birds of New Guinea. We find two species of Eupetes, a curious Malayan genus allied to the forked-tail water-chats; two of Alcippe, an Indian and Malay wren-like form; an Arachnothera, quite resembling the spider-catching honeysuckers of Malacca; two species of Gracula, the Mynahs of India; and a curious little black Prionochilus, a saw-billed fruit-pecker, undoubtedly allied to the Malayan form, although perhaps a distinct genus. Now not one of these birds, or any thing allied to them, occurs in the Moluccas, or (with one exception) in Celebes or Australia; and as they are most of them birds of short flight, it is very difficult to conceive how or when they could have

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crossed the space of more than a thousand miles, which now separates them from their nearest allies. Such facts point to changes of land and sea on a large scale, and at a rate which, measured by the time required for a change of species, must be termed rapid. By speculating on such changes, we may easily see how partial waves of immigration may have enter ed New Guinea, and how all trace of their passage may have been obliterated by the subsequent disappearance of the intervening land.

There is nothing that the study of geology teaches us that is more certain or more impressive than the extreme instability of the earth's surface. Everywhere beneath our feet we find proofs that what is land has been sea, and that where oceans now spread out has once been land; and that this change from sea to land, and from land to sea, has taken place, not once or twice only, but again and again, during countless ages of past time. Now the study of the distribution of animal life upon the present surface of the earth causes us to look upon this constant interchange of land and sea-this making and unmaking of continents, this elevation and disappearance of islands as a potent reality, which has always and everywhere been in progress, and has been the main agent in determining the manner in which living things are now grouped and scattered over the earth's surface. And when we continually come upon such little anomalies of distribution as that just now described, we find the only rational explanation of them in those repeated elevations and depressions which have left their record in mysterious, but still intelligible characters on the face of organic nature.

The insects of New Guinea are less known than the birds, but they seem almost equally remarkable for fine forms and brilliant colors. The magnificent green and yellow Ornithopteræ are abundant, and have most probably spread westward from this point as far as India. Among the smaller butterflies are several peculiar genera of Nymphalidæ and Lycænidæ, remarkable for their large size, singular markings, or brilliant coloration. The largest and most beautiful of the clearwinged moths (Cocytia d'urvillei) is found here, as well as the large and handsome green moth, Nyctalemon orontes. The

beetles furnish us with many species of large size, and of the most brilliant metallic lustre, among which the Tmesisternus mirabilis, a longicorn beetle of a golden green color; the excessively brilliant rose-chafers, Lomaptera wallacei and Anacamptorhina fulgida; one of the handsomest of the Bupres tidæ, Calodema wallacei; and several fine blue weevils of the genus Eupholus, are perhaps the most conspicuous. Almost all the other orders furnish us with large or extraordinary forms. The curious horned flies have already been mentioned; and among the Orthoptera the great shielded grasshop

pers are the most remarkable. The species here figured (Megalodon ensifer) has the thorax covered by a large triangular horny shield, two and a half inches long, with serrated edges, a somewhat wavy, hollow surface, and a faint median line, so as very closely to resemble a leaf. The glossy wing-coverts (when fully expanded, more than nine inches across) are of a fine green color and so beautifully veined as to imitate closely some of the large shining tropical leaves. The body is short, and terminated in the female by a long curved sword-like ovipositor (not seen in the cut), and the legs are all long and strongly-spined. These insects are sluggish in their motions,

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depending for safety on their resemblance to foliage, their horny shield and wing-coverts, and their spiny legs.

The large islands to the east of New Guinea are very little known, but the occurrence of crimson lories, which are quite absent from Australia, and of cockatoos allied to those of New Guinea and the Moluccas, shows that they belong to the Papuan group; and we are thus able to define the Malay Archipelago as extending eastward to the Solomon Islands. New Caledonia and the New Hebrides, on the other hand, seem more nearly allied to Australia; and the rest of the islands of the Pacific, though very poor in all forms of life, possess a few peculiarities which compel us to class them as a separate group. Although as a matter of convenience I have always separated the Moluccas as a distinct zoological group from New Guinea, I have at the same time pointed out that its fauna was chiefly derived from that island, just as that of Timor was chiefly derived from Australia. If we were dividing the Australian region for zoological purposes alone, we should form three great groups: one comprising Australia, Timor, and Tasmania; another New Guinea, with the islands from Bouru to the Solomon group; and the third comprising the greater part of the Pacific Islands.

The relation of the New Guinea fauna to that of Australia is very close. It is best marked in the Mammalia by the abundance of marsupials, and the almost complete absence of all other terrestrial forms. In birds it is less striking, although still very clear, for all the remarkable old-world forms which are absent from the one are equally so from the other, such as pheasants, grouse, vultures, and woodpeckers; while cockatoos, broad-tailed parrots, Podargi, and the great families of the honeysuckers and brush-turkeys, with many others comprising no less than twenty-four genera of land-birds, are common to both countries, and are entirely confined to them.

When we consider the wonderful dissimilarity of the two regions in all those physical conditions which were once supposed to determine the forms of life-Australia, with its open. plains, stony deserts, dried up rivers, and changeable temperate climate; New Guinea, with its luxuriant forests, uniformly hot, moist, and evergreen-this great similarity in their productions is almost astounding, and unmistakably points to a