LESSON XI.

VANISHED FAUNA.

“I said: ‘When first the world beganYoung Nature through five cycles ran,And on the sixth, she moulded—man.’”

“I said: ‘When first the world began

Young Nature through five cycles ran,

And on the sixth, she moulded—man.’”

—Tennyson,The Two Voices.

The old fairy tales inform us of genii, and gnomes, and brownies that live underground, and in rocks and caves, guarding treasures of gold and of gems. Let us fancy that there are truly genii and gnomes that have lived from the time when life began until now.

In every passing age each country has had its peculiar forms of animal life: these are called its fauna. The plant-life of an age or country is called its flora. As each age of earth-building came, it brought its especial fauna and flora. As the age passed away, this plant and animal life went away with it, and returned no more.

But from every age some form or type has lingered until now. The pretty little lamp shells of the China seas comefrom the far-off second period of world-building. Some of these forms that have lived through all the ages have changed much to suit the conditions of new times; others have scarcely changed at all.

And from all these periods, hidden in rocks and earth-beds, are frail remains of things that lived and perished long ago. Let us fancy that gnomes and genii keep these wonderful treasures.

THE LOST BEASTS.

In the distribution of the plants and animals of past ages we read much of the earth’s history. For instance, when we find buried under the later soil of England, the bones of elephants and hyenas, and the leaves and fruits of palms orother tropical plants, we decide, on reasonable grounds, that at some period the climate of England has been warmer than it is to-day. Similarly, when in layers above these tropical specimens we find the relics of an Arctic vegetation, and the skeletons of elk and bears that belong only to polar or subpolar regions, we conclude that the days of tropical warmth in England were succeeded by days of polar cold. Again, when we find under the warm plains of South France the remains of animals and vegetables now belonging to Siberia, we say, “In former ages France had a reign of Siberian weather, for a period sufficiently long to permit the growth of Siberian plants and animals.”

When we trace in regular succession the remains of such organisms back to the edge of the Polar circle, we say, “This northern cold, which once dominated all the hemisphere, slowly retreated to its present limits, and with it went its appropriate flora and fauna.” In all these instances the animals afford better indications than the plants, for plants have less capability than animals of adjusting themselves to new and untoward circumstances. If exposed to unusual cold or heat the plants die out, but many of the animals take thinner or thicker coats, to suit their new environment.

Very nearly all the species of plants and animals belonging to the five cycles of earth-building preceding our own have perished. No doubt there were many of the early living organisms which disappeared and left no trace; the first ages may have been far more abundant in varieties than we imagine them to have been. Many hundred of different families have been found, and perhaps as many more flourishedand utterly disappeared. We observe, concerning all these old-world families, that when once they perished they are, as we say, “gone for good”; a type does not disappear and reappear.

As one description of animals became extinct, another was ready to take its place. This constant succession of animal types represents a constant approach to those creatures best fitted to occupy the earth with man. We have now on the earth large and destructive animals, as the rhinoceros, the hippopotamus, the lion, tiger, alligator, boa-constrictor, and others, but all of these “are tamed, or have been tamed, of mankind,” and constantly recede before the advancing demands of the human race for territory.

But many of the earlier forms of life were so enormous and so destructive, that man could by no possibility have debated with them the empire of the globe. The battle would have gone the wrong way for man. It is well that various changes removed these creatures before man appeared.

Another consideration is here of great interest; the forms of life which survived their respective cycles, and came down nearly unchanged to our day, were not the strongest and largest creatures, apparently best able to fight their battle and live; but many of the feebler and smaller creatures, which, if we had been spectators of those ancient times, we should have expected to see perish under the encroachments of monsters and dragons of their day. As, for instance, the large, strong, numerous, armor-plated trilobites[22]of the second earth-age perished ages ago, while the little lamp shells live on until now. Far back in the reptile time, little mammalquadrupeds, scarcely larger than rats, ran in the woods, and these types have been continued with various adaptations in the marsupial or pouched animals, like the opossum of our own day, while the vast scale-dressed giants have only left a few of their scattered bones to tell their story. The dragon-fly survives, very like his ancestors of the Triassic period, while the mighty pterodactyles,[23]a kind of reptile bat that pursued the dragon-flies as part of its prey, have gone never to return. The flying reptile has left us only his enormous lithograph upon the ancient rocks, while still each year the jewel-like dragon-fly, once the big beast’s defenceless prey, bursts his brown case, and comes forth informed with light and life.[24]As the poet tells his story:—

“To-day I saw the dragon-flyCome from the wells where he did lie,—An inner impulse rent the veil,Of his old husk; from head to tailCame out clear plates of sapphire mail.He dried his wings, like gauze they grew;Thro’ copse and pastures wet with dew,A living flash of light he flew.”

“To-day I saw the dragon-flyCome from the wells where he did lie,—

“To-day I saw the dragon-fly

Come from the wells where he did lie,—

An inner impulse rent the veil,Of his old husk; from head to tailCame out clear plates of sapphire mail.

An inner impulse rent the veil,

Of his old husk; from head to tail

Came out clear plates of sapphire mail.

He dried his wings, like gauze they grew;Thro’ copse and pastures wet with dew,A living flash of light he flew.”

He dried his wings, like gauze they grew;

Thro’ copse and pastures wet with dew,

A living flash of light he flew.”

We should not forget that each one of the earth-building ages had some particular form of animal life which seemed in that age to be king, and conquer the other animals. Also in its own age each of these forms reached its greatest strength and perfection. Then in after ages, when some new type was dominant, the former types that still survived became smaller and more feeble.

We have crabs and other crustacea now-a-days, but none so enormous as in the second world-building age when they first appeared. The mollusks,[25]which you call shell-fish,[26]were largest and most numerous in the upper Silurian time. The sea-weeds that flourished with these crabs and mollusks were larger and more splendid than any sea-weeds now, for this is the age of man, and grass, and corn, not of crabs and sea-weeds.

Before man came into the world the woods and waters swarmed with great reptiles. There are none such now-a-days,—reptiles with long legs, reptiles with wide wings! Shall we see what they were like? The great objection to them is that they have such hard names. Among distinguished examples of the “vanished fauna” was the lælaps, which from its relics we conclude to have been a ferocious land-lizard, fierce and huge; but as yet its form and habits have not been fully decided.

We know more of the reptile bat, a fellow-citizen of the lælaps, and well-fitted to hold his own in the society of that grim monster, for to ferocity and size it added the accomplishment of flight. Was it then a bird? No; it was more like a bat. The largest pterodactyles found have been discovered in Kansas, and the remains suggest animals perhaps eighteen feet in extent of wing.

It is singular that the smaller forms of these creatures had teeth, and the larger ones were toothless. The legs and feet were very weak and had small claws. In our bats the tip of the wings has a claw, sharp and hooked; the pterodactylesseem to have had no claws on the wings. Some think that the bodies of these flying creatures were well covered with scales, but there is no clear evidence of this fact. The upper-arm bone was of moderate length; the forearm, of about the same length, had two bones, and had claws on the first three fingers, and then the fourth finger stretched out to several feet in length and sustained the membrane that formed the wing. The flight must have been jerky and uneven like that of bats. The famous roc, seen by Sinbad the sailor, fades into insignificance before this creature out of Nature’s wonder-book; and the great vulture of the Alps,[27]which carried off lambs and even babies, and is now happily extinct, must have been, compared with the ancient reptile bat, a small and gentle flying thing.

Another wonderful family of animals that now-a-days exists only among the rock treasures of the genii were the mosasaurs, whose nature and habits were long subjects of dispute. Specimens of these creatures have been found over eighty feet long, with a skull more than a yard long, and the jaws set with strong, cone-shaped teeth. The trunk of this reptile was ribbed like that of a snake, and it possessed two pairs of webbed feet, or paddles, to guide its course in the water. On land it must have moved with the wave-like motions of a serpent. It was covered with small scales, and was driven through the water by strokes of its mighty tail.

No animals perhaps are of more interest among the vanished forms than the ancestors of thehorse. We first trace it several ages before man appeared, as a small creature notlarger than a fox, with four toes on each foot, and the rudiments of a fifth toe; it had also two bones in the lower part of the leg. After this little creature came a horse-like animal as large as a sheep, with only three toes, the middle one being much longer and broader than the others, while the two bones of the lower leg began to unite.

The next age shows us a horse as large as a Shetland pony; the two bones of the lower leg are merged into one; the big middle toe occupies nearly all of the foot. And finally, shortly before human beings came into the world, we find a true horse. The big middle toe had come to occupy almost the whole foot. Its nail had enlarged and strengthened to a hoof. Thus we see that the horse really stands on the tip of a single toe of each foot. Meanwhile, as the lower leg and the foot thus modified, the horse gained his present size, symmetry, beauty, and strength.

FOOTNOTES:[22]For description of trilobite, see p.119.[23]PronouncedTer-o-dak’-tils.[24]Nature Reader, No. 2, Lesson 43.[25]Nature Reader, No. 1, Lesson 34.[26]Nature Reader, No. 1, Lesson 34.[27]Nature Reader, No. 3, page 238.

[22]For description of trilobite, see p.119.

[23]PronouncedTer-o-dak’-tils.

[24]Nature Reader, No. 2, Lesson 43.

[25]Nature Reader, No. 1, Lesson 34.

[26]Nature Reader, No. 1, Lesson 34.

[27]Nature Reader, No. 3, page 238.

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