Imagens das páginas

sent, however, our knowledge of fossils in this respect is limited to the bones of various quadrupeds, partly obtained from caverns in limestone, and partly from rolled and transported material corresponding with our gravel. There is, on the whole, a great poverty in the number of generic and specific forms in this large tract of land, not only of the fossil remains of the larger land animals, but also with regard to the existing fauna, which, as well as that now extinct, is limited to a particular group of animals, all of them exhibiting a peculiar bony apparatus in the pelvis. In the female this is connected with the presence of a pouch, where the young are received at a very early period, and carried about for some time after birth, whence the animals are called marsupials, or pouched animals.* Fossil remains of animals of this kind have been already alluded to, as occurring in the secondary and older tertiary beds of our island.

In Australia, the existing marsupials, or pouched animals, include species having almost every peculiarity of structure and habit; and they are so organized, that, while some are mere vegetable feeders, others are omnivorous, and others again carnivorous. There is doubtless some reason why the animals of this singular continent should be separated by so

Of this remarkable group some species are found in the Molucca Islands; and one genus, containing several species, is peculiar to America; and, though chiefly confined to the tropical portions, is met with as far north as the United States, where, however, only a single species is found. The number of species in islands north of Australia (New Guinea, &c.) is probably not inconsiderable.-Waterhouse's "Mammalia, vol. i. pp. 2, 3.

broad and distinctive a character from those of the rest of the world.*

The fossil animals of Australia are also marsupial, and exhibit forms which, for the most part, are not very different from those still living. Some, indeed, offer peculiarities sufficiently striking, as well in point of size as structure, and of these we may mention two genera, the former being a gigantic wombat, and the latter representing in its proportions the elephantine animals of other continents, but still retaining the marsupial character. The bones that occur in a fossil state are sufficient to indicate many interesting conclusions with regard to the ancient inhabitants of this singular and now detached continent; and, combined with the knowledge we possess of the present and former inhabitants of the existing land in other parts of the world, they lead us to suppose that different orders of the great class of mammalian Vertebrata have been fitted to inhabit, or at least have been chiefly developed in different countries; and that, while Europe, Asia, and Africa, with the adjacent islands, form one principal district, and are also connected with North America; the recently elevated continent of South America forms another, and Australia a third; but we find that, in the vast tract of land in the northern hemisphere, there is the greatest variety of types, corresponding, it may be, with a more varied character of the land, and the differences of climate thence involved.

But Australia is not entirely unconnected zoologically with the northern continents. It contains,

* I have already alluded to the possibility that this character may have reference to the physical geography of the districts inhabited by the group. See ante, p. 207.

in addition to its numerous marsupial animals, one species which is considered to be a true Mastodon. It is thus brought into relation with distant countries by a genus which forms a link between the tribes inhabiting Europe, Asia, and Africa, and North and South America. This fact is the more interesting, since the widely spread and cosmopolitan animal in question seems to have been amongst the last of those mighty tenants of the earth that ceased to exist immediately before man was introduced.

Very few of the islands near Australia, except Van Diemen's Land, and very few indeed of those other islands which form the numerous archipelagos of the eastern and southern seas, are sufficiently well known, or have such an extent of superficial detritus, that we could with any reason expect them to furnish much palæontological evidence. New Zealand is, in point of fact, the only island from which such remains have been obtained; and the condition of the bones, and the circumstances under which they are found, render it impossible to state very decidedly in what bed they there occur. It is, however, something to know that in these islands there existed formerly, and possibly not very long ago, a considerable and important group of wingless birds, of which one representative, the Apteryx, still remains, although apparently that also will soon be lost. Many extinct species of these strange animals have been found in the gravel of the northern island, and they vary greatly in size, some having been far larger than the largest ostrich, while others were very small. In all these the general character is nearly the same, the animals being much stouter and more powerful in

proportion than the ostrich, and absolutely without any trace of wings. The general outline of one of the largest of these extraordinary animals, of which a figure is given in the annexed wood-cut (fig. 144), will afford some notion of the vast proportions attained; the figure of a man being drawn to the

Fig. 144


same scale as the bird, to assist the eye in judging of the dimensions. The various species hitherto determined have all been referred to a single genus, under the name Dinornis.* The legs of the Dinornis

were powerful, and were no

doubt well adapted for

rapid locomotion; and in the Apteryx similar power

+ Aɛivos (deinos), enormously large; opviç (ornis), a bird.

ful extremities enable the animal to run swiftly, and when attacked to defend itself with great vigour. The Apteryx is nocturnal in its habits, and dwells in the deepest recesses of the forest, where gigantic trees are interwoven almost impenetrably with climbing plants, and where, deeply embayed in the mountains, there occur open swampy spots covered with bulrushes. It feeds on insects and seeds.

The islands of New Zealand, situated to the east of Australia, are still farther removed than that continent from the groups of islands in the Indian Ocean; but, in spite of their distance, it is in these latter that we find the nearest analogue to the singular wingless birds just described. The Dodo, which had been brought to England and preserved in museums more than two centuries ago, and figures of which have been given, appears to have inhabited the Mauritius and the island of Bourbon at no distant period, although for some centuries it has not been seen in a living state. Like the extinct wingless birds of New Zealand, it was nearly allied to the cassowary, also an inhabitant of the Mauritius, but it was more massive, and of more clumsy proportions.

The study of the tertiary geology of Asia, Australia, and the islands of the Pacific and Indian Oceans, assisted by broad general views of the physical geography of those countries, seems to point to them as among the chief districts which have undergone changes during the latest geological period; and there is every reason to conclude that they are still being greatly modified by undulatory movements on a grand scale, constantly going on over a large part of the earth's surface. At the commencement

« AnteriorContinuar »