Footnote 58. Proteus anguineus.

male with his crested back, the smooth mother, and the young eft-tadpole with its branching tufted gills (Fig. 16). They are much less active than the frog, for they never lose their tails, and they come less often out of the water, although they are true air-breathing animals. Then, when we go to other countries, there is the Proteus (Fig. 17), that curious half-transparent newt, with a round body and tiny helpless legs, which lives in eternal darkness in the still underground pools of the Carniola caverns near Adelsberg. He has become well fitted for his dismal life, for his tiny eyes are grown over with skin, and he never loses the feathery gills on each side of his neck, but lives like a tadpole all his life, although he has true lungs. Again, in America we

have the Siren, with its long snake-like body, and only front legs, with which it cannot walk. It, too, keeps its gills as it wanders about the stagnant waters of South Carolina, feeding on worms and insects. Then in the Mexican lakes there are the curious Axolotls, which also wear outside gills, as a rule, all their lives, and fathers, mothers, and children remain breathing in the water together, although they have real lungs. But about twenty years ago, some of those axolotls, which were kept in the Jardin

des Plantes in Paris lost their gills, came out upon the land, and astonished people by becoming true land salamanders, like some already well known and called Amblystomes, breathing only with their lungs. It was difficult for some time to make the world believe that grown-up water-breathing creatures which could lay eggs were able to turn into other creatures without gills. But at last a lady, Fraulein Marie von Chauvin, took some axolotls when they were full-grown, and kept them on land in wet moss, washing and feeding them every day, and thus succeeded in teaching them to breathe air, so that their gills shrivelled up and disappeared. Then there could no longer be any doubt that the axolotl is only the lower water-form of the amblystoma, which in the Mexican lakes, owing to the increased dryness of the surrounding country, has lost the habit of coming out on to the land, and remains in the water with its little ones all its life; but which, when brought to a moist climate where it can breathe comfortably on land, sometimes returns to its old double life.

Fig. 18.

Axolotl, a creature living and breeding for generations in the water. Amblystoma coming out of the water,—an axolotl which has lost the gills and acquired lungs.

We have, in fact, in Europe real land salamanders, which live in cool damp places, looking like lumpy soft-skinned lizards, but going down to the water to lay their eggs, that their little ones may go through their tadpole life—and one of these, the black salamander,[59] which lives high up in the mountains of Germany, France, and Switzerland, does not even go to the water, but carries the young tadpoles in her body till they can breathe air and run alone; and yet they are still true amphibia, for if they are taken out of their mother and put in water, they

Footnote 59. Salamandra atra.

go through all their changes like common efts and newts.

Lastly, there is a strange group of legless creatures called Cæcilians, which have taken refuge underground, burrowing like worms, though they are true amphibians and their young have gills in their babyhood hidden under a slit in the neck. These cæcilians are the only amphibians which have scales something like fishes, yet they never live in the water, but in the marshy ground of tropical countries, feeding on worms and insects.

* * * * *

Now when we think that these sluggish newts, and salamanders, and cæcilians, with their more nimble but comparatively unprotected relations, the frogs, are all the amphibians now living, we cannot but wonder how Life came to produce such a feeble set of creatures to fight the battle of existence.

But if we glance back to that far-off time when the ancient fishes were wandering round the shores and in the streams of the coal-forests, we shall be better able to read the riddle. For in those days it was a great step for an animal to get out of the water at all, and those that did so had a much better time of it than our frogs and newts have now, when the country is full of land enemies.

And so we find that the amphibia were not then the small scattered groups they are now, but strong lusty animals, with formidable weapons. In the hardened mud, which in those days formed the soft swampy ground of the coal-forests, but is now stiffened into the roofs and floors of our coal-mines, footprints have been left which tell us of large and formidable creeping animals, with toed feet and long flat tails, dragging themselves over the marshes of the coal-forests, and finding their way to many places which even the mud-fish with their paddles could not reach; and from time to time, in these same roofs and floors of our mines, both here and in America, we find the bones and coverings of these amphibia, buried in Nature’s catacombs for ages, and only brought to light by the rude hand of man.

These remains remind us that

“A monstrous eft was of old the lord and master of earth,

For him did the high sun flame, and his river billowing ran.

And he felt himself in his force to be Nature’s crowning race;”

for they show us huge and powerful creatures[60] which sported in the water or wandered over the land with sprawling limbs, long tails, and bones on which gills grew, while their heads were covered with hard bony plates, and their teeth were large, with folds of hard enamel on the surface. Some of these were fish-like, with short necks and broad flat tails, but they had true legs and toes; others, more like crocodiles, and sometimes ten feet long, were able to walk firmly, but still dragging their bodies and long tails over the swampy ground on which their footprints are still found; some were small and more like lizards, with simple teeth, scaly armour, and light nimble bodies; and these, probably, ran about quickly on the land, and have sometimes left their skeletons in the hollow trunks of the old coal-forest trees.

All these plated and formidable creatures were amphibia or double-lived animals, and this was their Golden Age, as they preyed upon the fishes in the

Footnote 60. See Picture-heading, p. 70.

swamps and ponds, probably not sparing even their nearest connections, the mud-fishes, who, less fortunate than themselves, had followed the road of fish-life instead of coming out upon the land. They lived so long ago that we can tell but little of their daily lives, but it is clear that they played a very different part from our small frogs and newts of to-day, and in their well-formed limbs were worthy forerunners of land and air-breathing animals.

But like the old race of fishes these large amphibians were only to have their day, for as other branches of the family tree grew up, and reptiles grew strong and mighty, and other true land animals began to flourish, these huge plated forms dwindled away, and we lose sight of them; and when we find any of their relations again it is only as our present frogs and newts, salamanders and cæcilians, which have taken up their refuge in lakes, ponds, ditches, underground waters, or damp mud. And, curiously enough, those forms of to-day which are most like the huge Labyrinthodonts,[61] as they are called, of the old coal-forests, are the feeble cæcilians, with their horny scales and their numerous ribs, although they have now fallen the lowest of all amphibians, and, with their sightless eyes and ringed and legless bodies, have taken to burrowing in the ground like worms.

Not so the frogs, which, like the bony fishes, began their career in later times, and have known how to fit themselves into many nooks and corners in life. In almost all countries of the globe they hop merrily about the ponds and ditches, never wandering far from the water, into which they

Footnote 61. Labyrinthodonts (Laburinthos, spiral; odontas, teeth).

jump and dive whenever danger threatens. It is true they are eaten by thousands, both as tadpoles and frogs, by birds, snakes, water-rats, and fish, and even by each other, but they multiply fast enough to keep up the supply, and find plenty of insects both in and out of the ponds. Nor have they kept entirely to a watery life, for their near relations, the toads, which have toothless mouths and toes less webbed, have ventured much farther on to the land, protected partly, no doubt, by the disagreeable acrid juice which they can throw out from a gland behind the eye whenever they are attacked.

It is curious to notice the quiet leisurely waddle of the sluggish toad, as he spreads out his short fat legs and puffs out his warty skin, and to compare him with the nervous, anxious, little frog, starting at every danger. And still more curious is it to see him getting out of his skin, as he does several times a year. For his skin does not peel off in pieces as it does in the watery frogs, but splits along his back; then he wriggles about till it lies in folds on his sides and hips, and, putting one of his hind feet between the front ones, draws the skin off the leg like a stocking off a foot. With the other leg he does the same, and then, drawing out his front legs, pulls the whole skin forward, and stripping it over his head, swallows it; thus deliberately putting his old coat inside him, and appearing in one that is glossy, fresh, and new. The toad has many enemies in spite of his acrid taste, and he shows his wisdom by hiding in walls and under stones in the daytime, and coming out in the dusk of evening to hunt the beetles and grubs so often out of reach of the water-loving frog.

Fig. 19.

The Flying Tree-Frog of New Guinea[62] (Wallace).

But the toad is not the only land relation of the frog; there are others of the group that venture even farther from water; for in most parts of the world (though not in England), tree-frogs, with sucking disks at the ends of their toes and fingers, climb the trees and hunt for insects among the leaves and branches; while in Borneo Mr. Wallace found one (Fig. 19) with

Footnote 62. Rhacophorus Rheinhardii.

webbed feet, which it spread out, and so flew down from the trees. There are plenty of the ordinary tree-climbing frogs to be seen in the south of France, their small green bodies peeping out from under the dull gray olive-leaves; and to be heard, too, in an endless chorus all night long when the spring arrives.

But how can these tree-dwellers bring up their little ones in water? Some of them come down and lay their eggs in the ponds, and even sleep down in the mud in winter. Others lay their eggs in little puddles of water in the hollows of the trees, and there the young ones live their tadpole life; while in one curious tree-frog of Mexico, called the Nototrema, the mother has a pouch in her back, and the father places the eggs in it for the little tadpoles to live in a moist home till they leap out as perfect frogs.

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