Chapter 4

The IllustratedStory of Evolution

Our fathers, many ages ago, looked out upon the world with mingled feelings of reverence and fear. They saw the sun that dazzled their eyes with the brightness of his beams as he flamed his way across the path of day; they saw the white light of the moon, hung like a spirit lamp amid the clouds that sailed over the face of night; they saw the stars, now spangling the darkness with the glory of their sheen, now veiling their faces with the sable void; they saw the infinite variety of plants, the animals of every size and form; they saw man himself, the master of the earth; and they would know something of the mighty scheme. They did not dream of natural law, but they were curious. Destitute of science, they were full of wonder. What could be the driving power back of what they saw? Existence was a challenge. They must essay an explanation. Their minds refused to rest content in ignorance. They must know how things came to be.

It was the age of gods. Gods were in the wind and rain, in the flood and flame, in the roar of the thunder and the echo of the forest gorge, in the harvest that sustained and the disease that destroyed—in everything that helped or hurt the sons of men. Man could do things; the gods could do things too. Man could build a home; the gods could build a world. So reasoned our primitive fathers. Of this reasoning were born the creation stories of the ancient religions; and these stories, coming down to our day, have fixed the beliefs of countless generations of men.

In one of these creation myths, regarded as of divine authority because it is found in the Bible, we are naively told that the world with its myriad forms of life and the star-studded universe beyond, were created in six days; and as this childish story is inseparably interwoven with popular religious notions, millions still regard it as sacredly true.

But this is an age of science, of a growing knowledge of reality. During the last few generations, the facts of nature have been studied as they never were studied before. As a result of this study, nature has yielded to man’s inquiring mind a growing knowledge of her methods. This knowledge is now accepted by the educated world as the science of evolution.

Fig. 1.—The Great Nebula in Orion.This illustration and the four that follow are reprinted from Sir Robert Stawell Ball’s “The Earth’s Beginning,” with acknowledgments to Cassel & Co., London, and D. Appleton & Co., New York.

Fig. 1.—The Great Nebula in Orion.

This illustration and the four that follow are reprinted from Sir Robert Stawell Ball’s “The Earth’s Beginning,” with acknowledgments to Cassel & Co., London, and D. Appleton & Co., New York.

We can imagine only two ways by which the world and its forms of life came into existence. One is to suppose that all things were created out of nothing, and made perfect at once, by a being of infinite power and intelligence who never had beginning. That is the biblical, the miraculous, the supernatural way. The other is to suppose that the raw material always existed, and that all things have been developed from primitive origins, the higher forms gradually emerging by evolution out of the lower. That is the scientific, the natural way. The first view is an assumption utterly devoid of support. The evidence proves that nothing was made, that things have grown.

Not only do we know that a creating God is a mere guess; that he is unthinkable in quantity or quality, that he bears no conceivable mark of reality; not only do we know that the creation of a universe out of nothing is wholly unintelligible; but the evidence of astronomy points clearly to the conclusion that our planet has been evolved by condensation from a nebula—from the raw material of which worlds are made; the evidence of geology portrays the fact that the earth has become what it is through a process of continuous change covering many millions of years; and the evidence of botany and of biology, studied in living forms and in fossil remains, proves conclusively that the plants and animals of the world have acquired their present character and mould as a result of infinite variations from and improvements upon the first simple forms of life that arose in the primeval world.

Fig. 2.—The Great Spiral Nebula.

Not creation, then, but evolution, is the secret of the world’s infinite diversity of things. Nothing was made; everything has grown. Perfection is not at the beginning, but at the end of nature’s efforts. All things have been fashioned by a process of endless transformation—blind, boundless, staggering, stumbling—at times falling back, but on the whole moving forward, pressed by the relentless forces inherent in substance and shaped in accordance with immutable law. Such a process has covered the earth with its amazing display of vegetation, and with its strange and wondrous population of things that swim and creep and fly and run.

In sketching the story of evolution, as that story is revealed to us by science, let us begin with the evolution of the starry heavens, that we may learn how the world was born.

As the giant telescope sweeps the abysmal depths of space over a distance of at least 4,000 billion miles, it reveals here and there among the hundred million stars, vast patches of cloud-like material. This material is called nebula, and it is the original substance of which all suns and planets are made. One hundred and twenty thousand of these nebulæ come within the range of the great Crossley Reflector at the Lick Observatory. The telescope photographs the nebula—celestial photography is one of the most interesting and instructive branches of modern astronomy—and when you look at a picture of a nebula, you see an actual photograph of an object that marks the beginning of Nature’s work.

Fig. 3.—An Elongated Irregular Nebula.

According to Sir Robert Stawell Ball, the nebula in Orion (Fig. 1), one of the most beautiful objects revealed by the telescope, covers an area more than a million times larger than that occupied by our entire solar system. Many of the nebulæ are of the spiral form, which shows their whirling motion. To the astronomer, the Great Spiral Nebula (Fig. 2) represents a mighty sun and system of planets in process of formation.Fig. 3shows an elongated, irregular nebula, from the Constellation Cygnus. This sketchy streak of nebulous material, although it is still many millions of miles wide, is but the remaining thread of a once mighty nebula that has condensed and is still condensing into the surrounding stars.

The nebulæ represent various stages of evolution into suns and worlds. Some resemble great clouds of rarified matter; some are distinctly spiral in form; some show advanced condensation into stars with attendant planetary systems. The stars, too, exhibit various degrees of progress from their birth in the nebula. Some are white, which shows that they are young; some are yellow, which indicates that they have reached middle age; some are red, which is the mark of their declining years.

Fig. 4.—Lunar Craters: Hyginus and Albategnius.

So the stars, the glowing suns, grow old and die, and, lifeless, wheel in space, like mighty cinders cold and dark, reflecting, like the moon, the light that shines on them from brilliant orbs.

The moon (Fig. 4) is a dead star. Its light and heat are gone. It wheels in space, an extinct cinder, and by the borrowed light which enables us to see the craters on its surface, it prophesies for us the fate that one day will overtake the earth. But that will be millions of years from now; so we need not worry!

But how is the nebula formed? The cluster in the constellation Hercules (Fig. 5), if it is not in fact a colossal nebula, shows that some of the stars are very close together. Now, these immense objects, that in blind fury dash through space, may come into collision with one another and explode into a nebulous cloud; or they may plough through dense swarms of meteorites, with a resultant explosion on a smaller scale; or, torn by internal convulsions, they may burst into fragments and scatter their dead dust over the abyss of space. In one or all of these ways the nebula is born, to begin again the recurring cycle of Nature’s life.

Fig. 5.—The Cluster in Hercules.

Is there further evidence of this? There is. On the night of February 21, in the year 1901, a luminous object appeared in the constellation Perseus. From a region where all was darkness the night before, a new and wondrous body now blazed forth its treasures of light. To the astronomers, who with lively curiosity watched the new birth for months, it meant that a tremendous conflagration had taken place in the heavens. A new nebula had been given to the universe, not, however, on the night when its light was first seen, but when Napoleon was dazzling the world with his victories; for the glowing mass was 500 billion miles away, and its messenger light, flying across space with the awful velocity of 186,000 miles a second, had been hurrying ninety-nine years to bring the news to our world!

Science now warrants a further step—one which reveals the origin and nature of matter—the ultimate source of the nebula itself.

Ether fills all space. It penetrates even the most solid substances. The universe of matter swims in an ocean of ether. Only by the presence of ether is the force of gravitation made possible—it must have ether upon which to act. The wings of ether alone transmit to us the light of the sun and stars. Now science is telling us that this indispensable ether, this infinitely attenuated and invisible substance, is the birthplace of matter—that atoms of matter are composed of minute centres of energy, or electrons, in ether. The atom is built of thousands of electrons whirling with inconceivable velocity in the space of their tiny, invisible universe; just as the visible universe is composed of myriads of suns and planets rushing forward through the boundless etherial ocean. Matter, then, whether nebulous or solid, was evolved out of the ether.

GENERAL TABLE OF THE STRATIFIEDSYSTEM AND FORMATIONS, Etc.Fig. 6.—A Pillar of Stratified Rocks.This illustration and others in this book are reproduced from Dennis Hird’s excellent work, “A Picture Book of Evolution,” with the kind permission of the publishers, Watts & Co., London.

GENERAL TABLE OF THE STRATIFIEDSYSTEM AND FORMATIONS, Etc.

Fig. 6.—A Pillar of Stratified Rocks.

This illustration and others in this book are reproduced from Dennis Hird’s excellent work, “A Picture Book of Evolution,” with the kind permission of the publishers, Watts & Co., London.

Millions of ages ago, a collision or an explosion produced a nebula in the region now occupied by our solar system. That nebula spread out over thousands of millions of miles of space. Here and there, in its mighty body, a more solid nucleus drew to itself volumes of the surrounding substance. In this manner the planets arose, leaving the sun, with his giant mass, in the center of the field. As the nebula revolved in one direction, mathematical necessity imparted to all the forming bodies a whirling motion around the central sphere. The smaller bodies cooled rapidly, so to speak, and crusted over; but the sun, owing to his immense bulk, has continued to glow through all these countless ages, and still sends forth enough light and heat to illuminate and warm many billions of worlds like ours. How long a time has elapsed since the earth began to condense from the nebula, the human mind cannot conceive; but Sir G. H. Darwin, the son of Charles Darwin, declares it is not unreasonable to suppose that from five hundred to a thousand million years have passed away since the moon was detached from the earth.

56Fig. 7.—Segmentation of the Fertilized Ovum and Gastrulation.4, morula; 5, section through blastula showing hollow sphere; 6, gastrula showing outer layer of cells (epiblast) and inner layer (hypoblast); the 6 is at the mouth of the cavity (enteron) of the gastrula. From Dr. D. Kerfoot Shute’s “A First Book in Organic Evolution.” Courtesy of The Open Court Publishing Co.

Fig. 7.—Segmentation of the Fertilized Ovum and Gastrulation.

4, morula; 5, section through blastula showing hollow sphere; 6, gastrula showing outer layer of cells (epiblast) and inner layer (hypoblast); the 6 is at the mouth of the cavity (enteron) of the gastrula. From Dr. D. Kerfoot Shute’s “A First Book in Organic Evolution.” Courtesy of The Open Court Publishing Co.

When the moon was born, the earth was in a plastic state, and many millions of years had yet to elapse before anything like a solid surface could begin to appear upon it. When, at length, the cooling globe did begin to form a crust, that crust was from time to time shattered to fragments by violent eruptions from within. Later, the immense quantities of hydrogen and oxygen that were in the atmosphere combined into molecules of water, and torrents of rain settled upon the hot surface of the earth. Owing to the large admixture of carbonic acid gas which it contained, the atmosphere was then fifty times heavier than it is to-day; but notwithstanding this great pressure upon it, the water that settled on the hot crust of the earth could not remain, and was sent, hissing, into the air in clouds of steam. The time came, however, when the cooling surface of the planet no longer offered such vigorous resistance to the water that fell upon it, and gradually as the rain fell, the earth became almost entirely covered with a boiling ocean. But the hot earth, even under the enormous weight of its ocean and its dense air, was restless, and as time passed away, great stretches of land emerged. Upon this new land, the rain now poured down in floods. This caused a great washing of debris into the surrounding sea. There the debris settled, and beneath the tremendous pressure of the ocean, it became solidified into the oldest stratified rocks.

Fig. 8.—Cambrian Fossils(above);Upper Silurian Fossils(below).

The rock pillar (Fig. 6) represents the rock formation of the crust of the earth. It gives us an idea of what a cross-section of the earth’s crust would look like, if all the rock deposits could be found superimposed one above the other in any one place. These rocks, built up layer upon layer, by sedimentary deposits in the ocean, are believed by geologists to reach a depth of more than forty miles; and it is held that it must have required at least a hundred million years—perhaps a thousand million years—to lay down all the strata, all the series of layers of rock, that form the crust of the globe.

That these immense depths of rock have been formed by a slow process of growth, of gradual up-building, is certain. The world was not made in a day. It has grown through innumerable ages. It is still growing. At the present time, the rivers of England are carrying away thousands of tons of land every year and depositing it on the floor of the sea. Every year the Mississippi river carries four hundred million tons of solid material into the Gulf of Mexico. This one stream alone displaces more than a million tons of solid matter every day. Similar things are occurring, in greater or less degree, in every part of the world. Everywhere rivers are widening and deepening their channels, cutting their way into mountains, depositing sediment for rock formations, or overflowing and fertilizing soil; everywhere mountains and hills are being worn down by the action of the elements; continents are crumbling into the ocean; island surfaces are rising above or falling beneath the waves. Nature is ever flowing. Throughout her infinite domain there is everlasting movement. Her trademark is eternal change. Nowhere is she at rest. Her labors never cease. To-day, as in the past, she builds and destroys. In her endless process of evolution, every day is a day of creation.

Fig. 9.—The Amphioxus.This illustration and several others used in this book are reprinted from J. A. S. Watson’s “Evolution.” Courtesy of The Frederick A. Stokes Co.

Fig. 9.—The Amphioxus.

This illustration and several others used in this book are reprinted from J. A. S. Watson’s “Evolution.” Courtesy of The Frederick A. Stokes Co.

These rocks contain fossils, the skeletons of creatures that lived during the periods when the rocks were being formed. This fact is one of the keys to the temple of evolution; for when we know the kind of fossils the different rocks contain, as we rise from the lower to the higher, we know the kind of creatures that lived in the various periods when those rocks were formed. Let myth-makers say what they will, Nature does not lie.

As the crust of the earth cooled, the enveloping ocean gradually lost its high temperature, and having fallen far below the boiling point, continued to be warm for ages. In that warm primeval ocean, where the various elements entered into all sorts of combinations, the necessary elements combined in the proper proportions, and, as a result of that happy combination, life was born into the world. Just as the requisite proportions of charcoal, sulphur and saltpeter unite in making gunpowder—a high explosive, vastly different from its constituent elements—so, simple elements, uniting in due proportions, produced the phenomenon of living matter.

Fig. 10.—The Earliest Known Form of Fish(upper);Three Other Early Forms of Fishes(lower).

Whether life is still being evolved from non-living matter, or whether its origin was confined to a peculiar set of favorable conditions—very high temperature, and unusual chemical and electrical conditions—in the early world, remains as yet unknown. On this question, the most distinguished biologists entertain diverse opinions. Among those who hold that the evolution of life is still one of the ordinary processes of Nature’s day’s work may be mentioned Professor Benjamin Moore, F.R.S., whose views are set forth in his excellent little work, “The Origin and Nature of Life.”

All living things, from the blade of grass to the giant oak, from the worm to the philosopher, are composed of cells, and all cells are composed of protoplasm. Protoplasm is, therefore, the physical basis of life. This wonderful substance is a compound of carbon, hydrogen, nitrogen and oxygen, and the story of the evolution of living things spells the limitless transformations of which this vital substance is capable.

In the world of to-day, we see the finished forms that have been beaten out, as it were, upon the anvil of the evolutionary process; and if we would appreciate the progressive march that life has made, from the simple forms of early days to the highly developed and complex creatures of to-day, we must trace the story of evolution through the numberless ages of the past.

Fig. 11.—Lampreys(left).The Mouth of a Lamprey(right).

The first living things consisted of a single cell—the Protozoa. As this cell grew, it divided into two; the two, having grown somewhat, divided into four; the four into eight; the eight into sixteen, and so on. In this way, the growing cells increased their numbers by division, and what was at first a single cell became an organized group of cells.Fig. 7illustrates the process of division and growth from the single cell—the fertilized ovum—to the gastrula. This division is the law of life. Every living creature begins its existence in this way.

Gradually, some cells specialized in the performance of the simplest animal functions, like the catching of food and digestion; and in the course of time, such simple forms of life as sponges and marine worms appeared. From flat worms, life advanced to the annelid or ringed worms—little creatures with a food canal and a body cavity filled with blood. In the worm begins the first development of the brain. A few sensitive cells in the fore end of the body, that beginning of mental life, is a far-flung prophecy of the genius that will one day thrill the world. Primitive depressions, lined with pigment cells, in the worm-like head, represent Nature’s first reaching for eyes; two other sensitive nerve pits are the beginning of the nose; yet a further pair of susceptible concave surfaces are destined to develop into the ears of land animals. Creatures with these primitive structures still exist among Nature’s lowly forms.

Fig. 12.—Lung Fishes.Australian Lung Fish, Ceratodus (top); South African Lung Fish, Protopterus (middle); South American Lung Fish, Lepidosiren (bottom).

Fig. 12.—Lung Fishes.

Australian Lung Fish, Ceratodus (top); South African Lung Fish, Protopterus (middle); South American Lung Fish, Lepidosiren (bottom).

From worms and worm-like creatures, were developed snails and a great variety of small animals, covered with shells. The Cambrian Rocks, the earliest rocks that have preserved fossils, have yielded the remains of some of these shell creatures (Fig. 8, upper). The Upper Silurian Rocks, belonging to a period much later than the Cambrian, have entombed the fossils of the molluscs shown inFig. 8 (lower).

We must understand that by this time living things had been evolving for millions of years, yet these shelled animals were the highest forms that had so far appeared. We must understand, too, that only the skeletons of creatures possessing a bony frame could be preserved as fossils. The fleshy part of the body, Nature destroyed. Moreover, it must be realized that of the countless billions of creatures that have lived, the rocks have preserved the fossil remains of only a few. We must not expect too much from Nature’s mutilated record. It is enough to know that the specimens that have been preserved prove the gradual unfoldment of life, and enable us to interpret the wonderful story of evolution.

Fig. 13.—The Flying Fish.

There is a small animal known as the Amphioxus (Fig. 9). Standing midway between the worm and the fish, its distinguishing peculiarity lies in the fact that it has a rod of cartilage—the notochord—extending along its back, over which runs a line of nerve cells. This creature, the child of the worm and the parent of the fish, is of singular importance, since it foretells the coming of the vertebrates—the creatures with a backbone. In due time the fishes were evolved from the Amphioxus. The first fish appeared in the Devonian period, that is to say, when about one-third of the whole geological series of rocks had been formed.Fig. 10 (upper)represents a fossil of the earliest known fish. The skeleton shows a primitive form. The lower specimens represent other early fishes. Observe the curious worm-like resemblance of the middle one. There are still fishes of very unfinished form. Lampreys (Fig. 11) show, as it were, fishes in the making. They have strangely undeveloped heads, no jaws, and only a crude sucker-like cavity for a mouth.

The early fishes had no bones in their bodies. Their skeletons were composed of cartilage. Primitive fishes of to-day—sharks, rays, and others—have no bones. These fishes continue lines of descent from ancestors that appeared before the bony frame had been evolved.

Life was born in the sea; it moved from the sea to the land; and when this advance was made, it was the fishes that led the way. Some fishesdeveloped lungs and began, tentatively at first, to live on the shore or in marshes. Life was moving towards the amphibians, and the evidence of its advance in this direction has been preserved. As the Amphioxus is the link between the worm and the fish, so lung fishes are links between the true fishes and the amphibians.Fig. 12 (at the top)shows the Burnett salmon, of Queensland—a fish with one lung; below are two mud-fishes of Africa and Brazil—fishes with two lungs. These lung fishes, or double-breathers, have the characteristics both of the fish and the frog. To scales and gills and fins and other features of the fish, they add lungs, nostrils, the beginning of a three-chambered heart, and other features of the frog. Living in regions from which the water periodically disappears, these creatures build around themselves in the dry season a shell of mud and leaves, and there, while awaiting the return of the water, they breathe air, and live on the fat stored up in their tails.

Fig. 14.—The Climbing Perch.

These lung fishes can walk on their fins; in fact, the fins of some of them are formed more like legs than fins.

The Flying Fish (Fig. 13) is another variation. This fish can sustain itself in the air for a hundred yards or more. Yet another curious fish that will not stay in the water is the Climbing Perch (Fig. 14). This fish may be seen crossing fields in India, and with the use of its fins it even climbs trees. These strange fishes are surely links to higher forms of life.

That the amphibian has been evolved from the fish may be seen in the evolution of the frog (Fig. 15). Number 1 shows the newly-hatched tadpoles; 2 and 2a show the branching, external gills; 3 to 8 illustrate further steps in the evolutionary process. The fish-like tail, so prominent in the early stages, is finally absorbed and we have the finished frog.

In the evolution of the frog we have a most suggestive illustration of the transformation of a creature during a single lifetime. The fish becomes an amphibian; the gilled, water-breathing creature becomes a lunged, air-breather; a water animal leaves its habitat for a home on land; a vegetable diet is abandoned for one of flesh. Truly a striking summary instance of the power of evolution!

Fig. 15.—The Evolution of the Frog.

All that man has become, all the wealth and worth of the civilization he has achieved, has been due to the fact that he has possessed a hand which could obey the command of his brain. Without a hand, without fingers, man would still be a wild beast of the forest. It was in the amphibian that Nature first produced the five divisions of the foot, which, inherited by the reptiles and then by the mammals, in the end became specialized into the human hand. The beginning of the hand is seen in the foot of the frog.

In the Carboniferous period, when the coal measures were laid down, appeared the wedge-headed amphibian, shown inFig. 16 (above)and later, in the Permian period, the roof-headed amphibian (Fig. 16, below) was born into the world. This roof-headed amphibian is all the more interesting, for from some of these creatures were born the reptiles, from which, in turn, arose the mammals.

From the amphibians were developed the true reptiles, and these branched out into many forms. Some lived in the water, some roamed on the land, some flew in the air. In a warm climate, and where food abounded, some of these creatures, like the Ceratosaurus (Fig. 17), the Atlantosaurus and the Diplodocus, grew to a prodigious size. Some were fifty, some a hundred, some a hundred and fifty feet long; some had a hundred teeth, and eyes fifteen inches across; some weighed ninety tons, and made footprints a yard square. It was in the Mesozoic times, millions of ages ago, when these ungainly monsters were the monarchs of the earth. Happily, they have long since been extinct, and to-day their colossal, though harmless, skeletons may be studied in the museums of the world.

Fig. 16.—The Head of the Famous Archaegosaurus.The wedge-headed Amphibian (above);the Branchiosaurus—the roof-headed Amphibian (below).

Fig. 16.—The Head of the Famous Archaegosaurus.

The wedge-headed Amphibian (above);the Branchiosaurus—the roof-headed Amphibian (below).

From the reptiles came the birds. The first birds had teeth, claws on their wings, and bony tails of many joints (Fig. 18). The fossil remains of two of these reptile-birds—the earliest birds known—were found, some years ago, in the Jurassic limestone strata of Bavaria. These creatures had thirty-two teeth, three clawed fingers on each wing, and a lizard-like tail of twenty joints, with two long feathers growing out of each vertebra. Occupying the ground midway between the reptile and the bird, having the characteristics of both—the link between the four-legged animal and the feathered songster of the air—the Archaeopteryx, as this ancient bird is called, was about the size of a crow.

Another line of development led from the reptiles to the mammals—the hair-clothed creatures that suckle their young. This was the most promising line of Nature’s advance, for at the end of this line, man was destined to appear.

Fig. 17.—The Ceratosaurus.A giant reptile of the Jurassic Period.

Fig. 17.—The Ceratosaurus.

A giant reptile of the Jurassic Period.

An amazingly curious link, which connects the reptile with the bird on the one hand and with the mammal on the other, is the Duck-bill (Fig. 19). This creature, whose home is in Australia, is covered with dense fur and suckles its young, like a mammal; but, on the other hand, it lays eggs like the reptile and the bird. The eggs have large yolks, like those of birds; are hatched by the warmth of the mother’s body; and when the young is born, it lives on milk drawn from its mother’s breast. Observe, too, that the mother Duck-bill has no nipples, but mere depressions in the breast, from which the milk oozes out among the fur, to be sucked up by the young. Think of a fur-covered, five-toed, web-footed, duck-billed, flesh-eating, swimming animal, housing itself in a burrow in the bank of a stream, being born from an egg, like a bird; formed in part like a reptile, and deriving its early sustenance by sucking the milk-ooze from its mother’s teatless breast! This link between reptile, bird and mammal, this crude combination of three forms of life, shows finished forms in the making. It is the living proof of the manner in which Nature has accomplished her work—of the steps by which evolution has advanced. It is what Darwin called “a living fossil.”

After the Duck-bills came the marsupial mammals—mammals whose young, born not yet fully developed, are carried for a time in a pouch attached to the body of the mother. The kangaroo (Fig. 20) belongs to this class. Here the advance is from an egg-laying mammal to one whose young is partly formed in the body of the mother. I say partly formed, for, although the kangaroo is as large as a man, its young, when born, though it is no larger than the little finger, is still a fœtus, so imperfectly formed that it must be carried for months in the mother’s pouch, so that it may complete its development as a babe. Meanwhile, being unable to feed itself, the mother, by an exercise of her muscles, forces milk down its throat. Once more Nature, in her forward march, is blazing a new trail. Life, by employing crude makeshifts and adaptations, is fashioning for itself a higher mould.

Fig. 18.—The Archaeopteryx.The lower picture shows the jointsof the tail with the tail feathers.

Fig. 18.—The Archaeopteryx.

The lower picture shows the jointsof the tail with the tail feathers.

The marsupial mammals were followed by the placental mammals, animals whose young are nourished before birth by a disc-like organ, called the placenta—the after-birth.

The Pariasaurus Baini (Fig. 21) shows Nature, the apprentice, trying to make a quadruped. I say trying, for see what a crude, raw specimen this monster was. The best thing that can be said of this fellow is that he had his day of fighting for a place in the sun and was then supplanted by higher creatures.

Many ages of progress, during which life assumed a rich variety of forms, including the early stages of most of the hoofed animals, brought the process of evolution to the lemurs, the monkey-like creatures that make their home in trees (Fig. 22). The lemurs differ from monkeys in that the milk glands of the female are on the abdomen instead of the breast, while the index finger of each hand, and the second toe of each foot, are furnished with claws, all the other fingers and toes having flat nails. Here again is a link between the lower and the higher life. Nature is stumbling and bungling, but getting there.

Fig. 19.—The Duck-bill,known in Australia as the Platypus.

After the lemurs came the Slow Loris (Fig. 23). This species of the Loris has no tail, and its front foot bears a strong resemblance to the human hand. From these creatures, or possibly from similar creatures, were evolved the true apes (Fig. 24), and from these came the anthropoid or man-like apes.

There are still in existence four genera, or kinds, of these anthropoid apes—the gibbon, the gorilla, the orang, and the chimpanzee. The gibbon (Fig. 25) shows an alert, human-like expression, which is fully borne out in his pose. The picture of a female gorilla (Fig. 26) suggests with even greater force that we have here a human being in the making. Yet this creature, be it understood, may be separated from the lowest living human being by millions of years of development. The giant gorilla (Fig. 27), shot by Paschen, in the Cameroons, differed from the ordinary gorilla in the development of the skull and in size. He was six feet, eight inches tall from the crown of his head to his middle toe; the span of his arms was six feet, nine inches; his chest measurement was twice as great as that of a strong man. Yes, a dangerous gentleman to meet!

Fig. 20.—A Kangaroo with her Young One in her Pouch.The illustration to the right shows a young Kangaroo shortly afterbirth. That the creature is a quite unfinished fœtus is obvious.

Fig. 20.—A Kangaroo with her Young One in her Pouch.

The illustration to the right shows a young Kangaroo shortly afterbirth. That the creature is a quite unfinished fœtus is obvious.

The approach to the human look on the face of the bald-headed chimpanzee (Fig. 28) is nothing less than remarkable. The form of the skull shows a decided advance towards the human. The countenance is, of course, a little open, but—well, the whole head so strongly resembles the human that he might almost be mistaken for one who believes the story of Jonah and the whale!

That man is related to the anthropoid apes becomes evident when his anatomical structure is compared with theirs (Fig. 29). While these creatures differ from one another as do the different races of men, as, for example, in the color of the skin, in the size and shape of the skull, and in the length of the arms and legs, they are all essentially man-like. And while all these creatures are like human beings in the formation of their skeletons, in their anatomical structure, and in their physiological functioning, each of them approaches more closely to man than any of the others in the development of some part of its body. Thus, “the orang approaches closest to man in the formation of the brain, the chimpanzee in the shape of the spine and in certain characteristics of the skull, the gorilla in the development of the feet and in size, and the gibbon in the formation of the throat and teeth.” Prof. Ernst Haeckel, in the “Riddle of the Universe,” sums up man’s relation to the anthropoids as follows:

Fig. 21.—The Pariasaurus Baini.This skeleton was found in thePermian Strata of South Africa.

Fig. 21.—The Pariasaurus Baini.

This skeleton was found in thePermian Strata of South Africa.

“Thus comparative anatomy proves to the satisfaction of every unprejudiced and critical student the significant fact that the body of man and that of the anthropoid ape are not only peculiarly similar, but they are practically one and the same in every important respect. The same two hundred bones, in the same order and structure, make up our inner skeleton; the same three hundred muscles effect our movements; the same hair clothes our skin; the same groups of ganglionic cells build up the marvellous structure of our brain; the same four-chambered heart is the central pulsometer in our circulation; the same thirty-two teeth are set in the same order in our jaws; the same salivary, hepatic, and gastric glands compass our digestive process; the same reproductive organs insure the maintenance of our race.”

Like human beings, these apes stand from three to six feet tall; like human beings, they weigh from one hundred to three hundred pounds; like human beings, they have only a rudimentary tail of from three to five joints imbedded at the extremity of the spine; like human beings, they stand on their hind legs and grasp things with their hands; like human beings, they live in families; like human beings, they are brave, quarrelsome, impulsive, emotional, and capable of a limited exercise of reason.

In their native forests, apes laugh, sing, dance, and converse with one another. Their language is a series of sounds with definite meanings.

Fig. 22.—The Ring-tailed Lemur of Madagascar.

Yet it is not held that man has descended from any of these existing anthropoid apes. What is held is that these creatures and human beings represent two different lines of development from the same ancestors.

But what of the “missing link” between the early ape-like creatures and primitive man? In 1891, Dr. Eugene Dubois, a Dutch military physician, found near Trinil, in Java, some interesting bones and some teeth. The International Zoological Congress, held at Leyden in 1894, voted that these bones had belonged to a form intermediary between ape-like creatures and men. The creature was named the Pithecanthropus Erectus—the erect ape-man.

Fig. 30 (upper)shows a restoration of the skull of this ape-like human being, placed, to facilitate comparison, above the skull of a modern man. The formation of the skull of this creature represents a decided advance over any existing anthropoid ape; but the prominent supra-orbital ridges, the low, retreating forehead, and the massive, prognathous jaws, which gave a brutish angle to the face, are distinctly ape-like characteristics.

Fig. 23.—The Slow Loris—another type of Lemur.There are fifty known species of lemur, of which thirty-six belong to Madagascar. The others are found in Africa and South-Eastern Asia. They were formerly much more widely distributed, and many fossil lemurs have been found in North America.

Fig. 23.—The Slow Loris—another type of Lemur.

There are fifty known species of lemur, of which thirty-six belong to Madagascar. The others are found in Africa and South-Eastern Asia. They were formerly much more widely distributed, and many fossil lemurs have been found in North America.

The most interesting feature of this primitive creature’s approach to man was the volume of his brain. The quantity of the brain of the highest ape measures about 600 cubic centimetre units. In some Australian “black fellows” the brain capacity runs as low as 900 units, while in others it reaches 1500. The brains of civilized men vary in bulk from 1000 to 2000 units, which gives 1500 cubic centimetres as the brain capacity of the average man. Now the skull of the Pithecanthropus Erectus shows that his brain measured nearly a 1000 cubic centimetres. In other words, the brain capacity of this primitive ape-man was about equal to that of some of the exceptionally low existing savages, and somewhat less than midway between that of the highest anthropoid ape and the average civilized man. This man lived some 500,000 years ago.

Men of science believe that the first human beings arose in Southern Asia, if not, indeed, in a region still more southerly than the present Asiatic boundary—in Lemuria, the former land extension now submerged beneath the Indian Ocean. The evidence of fossils supports this view. And it is significant that the bones of the ape-man of Java were found on the very edge of the Indian Ocean.

From Asia, the rude forefathers of our race migrated over the earth. Asia was then united to Africa, and joined hands with Europe at the Dardanelles and Sicily, and with North America at Behring Strait. Other land connections joined Africa to Europe at Gibraltar and flung a broad thoroughfare from the Dark Continent to Australia. Over these land routes and others some of our naked ancestors in humanity’s early dawn wandered from the cradle of the race in Asia and took up their habitations in the different continents and in the islands of the seas.

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