LESSON XVIII.
THE BURIED REPTILES.
“Hamlet.Do you see yon cloud, that’s almost the shape of a camel?Polonius.By the mass, ’tis like a camel indeed.Hamlet.Methinks it is like a weasel.Polonius.It is backed like a weasel.Hamlet.Or like a whale?Polonius.Very like a whale.”—Shakespeare,Hamlet.
“Hamlet.Do you see yon cloud, that’s almost the shape of a camel?
Polonius.By the mass, ’tis like a camel indeed.
Hamlet.Methinks it is like a weasel.
Polonius.It is backed like a weasel.
Hamlet.Or like a whale?
Polonius.Very like a whale.”
—Shakespeare,Hamlet.
What is the chief bone in the human body? Does any one say the arm, or leg, or breast-bone? No, it is the backbone, or spinal column. That is a wonderful bone that gives the name of vertebrate or backboned animals to all creatures which possess it. This spinal column, or backbone, is made up of a number of little bones or joints called vertebræ. These are threaded together like beads on a string. The spinal cord runs through them, enters the skull, and expands or blooms out into a brain. Bend your body every way, backward,sidewise, forward, how flexible is this many-jointed spinal column! This wonderful backbone marked the creatures that possessed it as a class higher than the jointed creatures or articulates.
THE REIGN OF THE PINE.
THE REIGN OF THE PINE.
We have found that the first vertebrate animals were fishes. The fish of the Devonian age were not only numerous and greedy, but instead of scales the majority of them wore large bony plates, which served them as armor while they fought, not merely for existence, but for conquest. At present there are only about thirty species of plate-wearing or ganoid fish in the world, and nine thousand species without this heavy armor. But in the age when fishes were kings of creation, this proportion was reversed, and the plate-wearing fish were the more numerous. The fishes were the only representatives of the backboned animals until the Coal age waswell advanced. Then a new vertebrate of a still higher type arrived in the world. These new creatures aped the fish in their backbones, or spinal columns, their thick skins, and their plate armor. But they were of a higher type than the fishes; for they were in possession of legs, toed-feet, and had lungs instead of gills for a breathing apparatus.
In the earliest representatives of this higher stage of life, the lungs were an air sac associated with gills, but the next form dropped the gills entirely, and had well-developed lungs. The possession of lungs gave them power to live out of the water, which hitherto had been the home of nearly all living things. The new vertebrates were amphibians, and no doubt the earliest of them found themselves better fitted to live in the water than on the land, as their legs were feeble, and their strong tails served them well in swimming; but like the amphibians of the present, they made themselves at home in any place.
The reptiles marked the introduction of a higher animal class than had previously existed, and being of a higher type, their destiny was to live and thrive and assert themselves. Almost immediately we note in the class two branches, or fashions, which continue to distinguish them. Some became very large, had enormous heads and jaws, and terrible teeth, resembling the present crocodiles. These, living on the shore, preyed upon fish or other animals. The second division comprised smaller and more delicate reptiles. They had better developed limbs and lungs, large ribs, beautiful, brightly colored scales and skins, lived on land, and fed on insects, spiders, and snails.
Thus in the latter part of the Coal-making age, we may imagine the shores and bayous swarming with great reptiles ten feet long, furnished with thick armor and monstrous teeth; while the forests of tree-ferns, club-mosses, reeds, and other plants, were rustling with the agile feet of gayly colored, active little beasts, from a few inches to a foot in length.
Here at last was an animal with a pair of nostrils through which it could inflate a pair of lungs. The reptile with his improved breathing apparatus and convenient feet had come into creation to stay. Individuals and families would indeed perish and leave only fossil remains to exhibit their characteristics, but the class was to remain. When the Coal period passed away, we find that the first lizards accommodated themselves in improved varieties, to the demands of the new time; their teeth, limbs, lungs, and tails, were better developed, and they could claim to be highly organized creatures; in fact, the reptiles became the leading animals of the epoch, which from them is often called the age of the reptiles. The crustaceans, corals, mollusks, and fish had had their day of being the rulers or leading families of the world; now came the turn of the reptiles; while certain groups, previously chief, sank into lower places.
These crustaceans, polyps, crinoids, and others which we have mentioned, were the predecessors of the reptiles. They did not disappear when the reptiles arrived, nor have they disappeared yet. No doubt all these creatures, and others which have come into existence, will survive and share the globe, as long as the globe lasts. No researches have discoveredany animals created since the arrival in the world of man.
While the foraminifera, crabs, corals, mollusks, fish, and other creatures came successively into the world of life, there is nothing to prove that any one class descended from the class preceding. There is no evidence that any mollusk, crinoid, or fish, though in existence a few thousand years before the reptiles, could claim to be the reptiles’ grandfather, and there is no likelihood that the inside skeleton of the backboned animal was developed out of the outside skeleton of the mollusk. We must take these successive classes as we find them: we see each class in itself, developing into higher and better types; then, some maintain this improved development, some dwindle away and disappear.
There will always be many things in nature which we cannot understand, but this need not discourage us in efforts to know; for the old saying is a good one—“He who grasps after a gold coat, is likely to get at least a sleeve.” In those old ages before man arrived, there were new things in the world. Since man came, there is nothing new under the sun: the facts which we learn and call new, are all old, very old.
The reptiles were of the improving classes of animals. To be in full harmony with their habitations, and not miss any of the possibilities of their kingdom, we find the reptiles accommodating themselves to the earth, the air, and the sea. There was, for instance, the hadrosaurus, a two-legged reptile, which had long, strong hind legs, and a strong, pointed tail. These legs and the tail formed a tripod, like the threelegs of a milking-stool, or the two legs and cane whereon an aged man supports himself. The enormous body of the hadrosaurus was upheld by the strong hind legs, and it paced slowly about: then when it wished to rest, or seat itself at ease, while with its small, hand-like fore-paws, it picked fruits and leaves from the tree-tops, it brought its strong tail into play, and rested on this and its legs. Thus we see the lucky hadrosaurus always carried about its own camp-stool. This creature was a land-living, herb-eating reptile.
One very great reptile of the sea was the ichthyosaur, or fish reptile. This creature had paddles and a very strong tail-fin for swimming. The ichthyosaur could roll in the heavy billows like a porpoise, and liked to be far out on the sea busy at fishing. As it chased fish at sea, it held its head high above the water and breathed air with true lungs. Probably no fish could hold its own against a monster twenty-five feet long and protected by broad, solid plates of armor. The empire of the fish had finally departed.
A third wonderful reptilian form was fitted for airy flights; the pterodactyl was the reptile monarch of the air. While its cousins, the biped reptile and the fish reptile, were ravaging the land and sea, the flying reptile, or bat reptile, whichever we choose to call it, spread its parchment-like wings, lifted itself far above the trees, and swooped from its height upon fish, land animals, or the few stray insects of the period. The flying reptile was a prophecy of the coming bird, which arrived in the middle part of this period.
When true birds came, they introduced a class that was very closely related to the reptiles. The lady whoholds a pet canary on her finger, offers it sugar with her lips, kisses its pretty yellow head, and considers it one of the most dainty and delightful of living things would, perhaps, shriek wildly if a lizard ran across her foot, or upon her sleeve, and would call the innocent little reptile, hideous, disgusting, hateful. Some one says the bird is a “glorified reptile.” There is similarity of structure, but the bird class is not descended from the reptile class.
The backboned animals are divided into the class of the fishes; the amphibians; the sauropsida, or class containing birds and reptiles, which you see are put together; and the highest class of all—the mammalians—to which we ourselves belong.
Some years ago it was usual to class together as “four-legged creatures that lay eggs,” all turtles, tortoises, newts, salamanders, snakes, toads, frogs, lizards, and crocodiles. The great naturalist, Linnæus, named all these creatures amphibia, because they can live with equal ease in the water or on the land. After this some of the French naturalists concluded that the creeping method of locomotion of these animals was a more general characteristic than their amphibious habit, and called them reptiles, or crawling creatures. But as these animals have been more closely studied, wider differences have been noted between them, and the toads, frogs, newts, and salamanders have been set in a class by themselves.
The study of nearly all forms of life has two branches, the investigation of living objects, and the similar investigation and classification of fossil specimens. Thus the study of fishes embraces not only the examination of those speciesnow to be found in the waters of the world, but of the fossil fish found whole or in parts, in the treasure-house of the rocks, and these fossil fish have very numerous varieties. Botany also regards not only plants now growing, but the varieties which have become extinct, during the five earlier earth-building periods. Of the ten orders into which it is common among scientists to divide reptiles, five are now extinct, and remain to us only as fossils. But so learned and accurate do some ardent students of fossil remains become, that from only a single bone, tooth, or scale, they are able to decide to what class and family the creature of which it was a part belonged, provided, of course, that the creature itself has become known.
No ancient creature seems to have accommodated itself more closely to its circumstances than the reptile. It appeared to be equally at home in the water, on land, or in the air; it ate fish, flesh, and vegetables; walked on two legs, or crawled on four. The biped land reptile had many of the characteristics of the present kangaroo; the bat reptile had many of the qualities of a bird; and the sea reptile was probably more like a whale than a fish. In fact the reptile seems to have been as complaisant as Polonius the courtier-friend of Prince Hamlet in Shakespeare’s play.
Let us now write out a little table for reference, showing the improving scale of life in plants and animals, from their first appearance until the reptiles came.
ANIMALS.
Amoeba.Foraminifera.Crustaceans.Polyps.Mollusks.Fishes.Amphibia.Reptiles.Crinoids.Spiders.Scorpions.Dragon-flies.Cockroaches.Kangaroo-rats.
PLANTS.
Sea-weeds.Mosses.Ferns.Reeds.Pines.Cycads.
The amphibia and reptiles brought into the world not only those famous backbones, but lungs and noses. The amphibia had at first gills and lung-sacs, but the reptiles had true lungs and drew air through their nostrils. Try it: draw in your breath and fill your lungs until your chest rises and expands; now breathe it forth again. Very simple that, do you say? So it seems; it is very common now-a-days, but there were many ages when not a living creature had a pair of lungs and a pair of nostrils, when such breathing apparatus would have been a marvellous affair. These reptiles introduced a brand-new fashion.
Each advancing age was richer in both flora and fauna than the ages that had preceded it, because the soil, climate, and atmosphere of the earth became more and more favorable to both animal and vegetable existence. Nothing in all this succession lived or died in vain. The plants freed the air of carbon and enriched it with oxygen;[41]the decay of animal and vegetable matter increased and enriched the soil.
FOOTNOTES:[41]Nature Reader, No. 3, Lessons 6, 7.
[41]Nature Reader, No. 3, Lessons 6, 7.
[41]Nature Reader, No. 3, Lessons 6, 7.