And this is just what we have reason to believe has been their history; for it is exactly in Australasia that we find that curious group of pouched animals, the kangaroos and other Marsupials,[108] as they are called, which are different from all the other milk-giving animals in the world, except the opossums of America, whom we shall speak of by-and-by.

Footnote 108. Marsupium, a pouch.

And together with these marsupials we also find the simplest milk-giving animals now living. Come with me in imagination to a quiet creek in one of the rivers of East Australia. It is a bright summer day, and the lovely acacias are hanging out their golden blossoms in striking contrast to the tall graceful gum-trees and dark swamp oaks in the plain beyond. Come quietly, and do not brush the reeds growing thickly on the bank; for the least noise will startle the creature we are in search of, and he will dive far out of sight. There he is, gently paddling along among the water plants. His dark furry body, about a foot and a half long, with a short broad tail at the end, makes him look at first like a small beaver. But why, then, has he a flat duck’s bill on the tip of his nose, with a soft fold or flap of flesh round it, with which he seems to feel as he goes? Again, he has four paws, with which he is paddling along; but though these paws have true claws to them, they have also a thick web under the toes, stretching, in the front feet (C Fig. 50), far beyond the claws, yet loose from them, so that while it serves for swimming it can be pushed back when the animal is digging in the ground. His hind feet have a much shorter web, and a sharp spur behind, like that of a game cock.

And now, as this animal turns his head from side to side you can see his sharp little eyes, but not his ears, for they are small holes which he can close quite tightly as he works along in the water, pushing his bill into the mud of the bank, just as a duck does, and drawing it back with the same peculiar jerky snap; for he too has ridges in his beak like the duck family, through which he sifts his food; while, at the same time, he has in his mouth eight horny mouth-plates, peculiar to himself.

What, then, is this four-footed animal with a beaver’s fur and tail, and teeth in his mouth, and yet with a duck’s bill and webbed feet? He is the lowest and simplest milk-giving animal we know of in the world—the duck-billed Platypus or Ornithorhynchus, called by the settlers the Water-mole.

Fig. 49.

The Duck-billed Platypus[109] swimming and rolled up, with its underground nest laid open behind; on the right hand bank is an Echidna.[110]

If we could search along the bank we should find,

Footnote 109. Ornithorhynchus paradoxus.

Footnote 110. Echidna hystrix.

somewhere below the water’s edge, a hole, and again, a few feet back on the land, another among the grass and reeds; and both of these lead into a long passage, which ends in a snug underground nest—a dark hole lined with dry grass and weeds—where in the summer time (about December) we should find the mother platypus, with two or four tiny naked young ones, not two inches long, cuddled under her. How these little ones begin life we do not know. The natives talk about finding soft eggs like those of reptiles; but it seems more likely that these eggs break just as they are laid, like those of our common lizard (see p. 105), and the naked little ones come out alive into the nest.

Fig. 50.

A, Head of Ornithorhynchus, showing serrated bill; B, Hind foot with claw a, found on the males only; C, Webbed fore foot.

And how are they fed? Their mother has no teat, like the cow, to put into their mouth, for she is a very primitive creature; only in one spot amid her fur are a number of little holes, and from these she can force out milk for them to drink as they press against her with their soft flat bills. So here, in a dark underground nest, away from the world, because she cannot, like the higher animals, carry

her little ones till they are perfect, the duck-billed platypus, which may well be called “paradoxical” (see Fig. 49), enables us to picture to ourselves how, in ages long gone by, mothers first began to feed their little ones with their own milk.

And now, perhaps, you will be struck by this animal’s likeness to a bird, especially when you hear that the little baby water-moles have a soft horny knob on their nose, just where young birds have a hard knob for breaking through the shell; and you will ask if milk-giving animals came from birds. Not at all; young tortoises, too, have such a knob, and so have crocodiles; and, moreover, these duck-billed moles have many parts of their skeleton, especially the shoulder bone and the separate bones of the skull, very like our living reptiles, and still more like some which lived in ages long gone by.[111] And yet at the same time they differ essentially both from reptiles and birds in many points besides those we have been able to mention, and in one in particular, which we can understand now we have studied these groups, namely, that the platypus, like all milk-giving animals, is without that curious quadrate bone (q, Figs. 23 and 33) which we find in all reptiles and birds.

Now, notice the frog, which is an amphibian and therefore lower than the reptiles, has not got this quadrate bone, though his companions the newts have; and he seems to tell us that among those old amphibians which roamed in the coal-forests of ages past,

Footnote 111. Professor Owen has described a reptile from the Trias of Africa, and Professor Cope another from the Permian of Texas, both having characters closely resembling the Platypus.

there must have been some which,—while they had that great mass of cartilage which imperfect, unborn, milk-giving animals have even now, out of part of which this bone is formed,—yet never went so far as to have the bone itself. If this is so, then here at last, in the distant past—so remote that we cannot even guess how long ago it may have been—we have a point from which the earliest ancestors of the milk-giving animals may have gone off in one direction, and those of reptiles and birds in another. And this would explain how it is that they have so many points in common, while yet the mammalia are without that special bone and other characters which are found both in reptiles and birds.[112]

Be this as it may, here is our lowest mammalian form, and he has a relation, the Echidna, very like him in many respects, but who has made a decided step forward; for on the sandy shores and in the rocky gorges of Australia, creatures about a foot long, covered with prickly spines like hedgehogs, and called by the settlers “Porcupine Ant-eaters” (see Fig. 49), shuffle along in the twilight, thrusting out their long thin tongues from the small mouth at the end of their beak-like snout, and feeding on ants and ants’ eggs. These do not belong, however, to the real ant-eater family, but are near relations to the platypus; and they are well protected by their spines in the battle of

Footnote 112. This argument, which can only be stated very roughly here, must not be supposed to rest merely on the quadrate bone, though this is the easiest point to illustrate popularly. I am deeply indebted to Mr. W. Kitchen Parker for a whole flood of light thrown on these early forms, and only regret that I have neither skill nor space to do justice to his graphic illustration of a subject of which he is pre-eminently master.

life, for when attacked they either roll themselves up into a ball like a hedgehog, or burrow down into the sand so fast that they seem to sink into it, leaving only the points of their prickles sticking out to pierce the feet of their enemy. Now these creatures have a little fold of skin under their body, which forms two little pouches over the milk-giving holes, and the little echidna when very tiny is put into this pouch, and keeps its head there while its body grows larger and sticks out beyond. In this way the Echidna can carry her child about with her, and she only turns it out to shift for itself when its prickles are hard and sharp.

* * * * *

You see, then, that though we began with the simplest known milk-giving animal, we are, in the Echidna, already fairly on our way to the curious pouched creatures of Australia, the “Marsupials,” which, instead of a small fold, have indeed a large pouch of skin, into which they put their little ones when they are less than two inches long, and so imperfect that their legs are mere knobs, and they can do nothing more than hang on to the nipple with their round sucking mouths as if they had grown to it.

There the little ones hang day and night, and their mother from time to time pumps milk into their mouth, while they breathe by a peculiar arrangement of the windpipe, which reaches up to the back of their nose. Then, as they grow, the pouch stretches, and by-and-by they begin first to peep out, and then to jump out and in, and feed on grass as well as their mother’s milk. For a long time they take refuge in the pouch whenever there is any danger or they are tired, and Professor Owen has suggested that this curious pouch arrangement may be of great use in a country where water is often so far to seek that the little ones could not travel to it unless the mother could carry them.

Fig. 51.

Australian Marsupials.

Kangaroos; a flying Phalanger; and the Kaola or native Bear, with a young one on its back.

Now this race of pouched animals we find spreading all over a land where they had none of the higher four-footed animals to dispute the ground with them, for there are no ordinary land mammalia in Australia,

except bats, which could fly thither; mice and rats, which could be carried on floating wood, and a fierce native dog, the Dingo, which was probably brought by the earliest native settlers long after the marsupials had spread and multiplied. And what is more, though we find the bones of marsupials of all sizes buried in the rocks of Australia, some of them as large as elephants,[113] showing that these creatures too had their time of greatness, we do not find those of ordinary mammalia.[114] It would seem, then, that for long ages the pouched animals had the field to themselves, and they made good use of it, filling all the different situations which in other parts of the world are filled by ordinary four-footed creatures.

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