Life originated in the sea, and for an immense period of time after
it commenced it was confined to the place of its origin. The
civilisations of the earth were for many millions of years
exclusively aquatic. It has, indeed, been estimated that the time
required by the life process in getting out of the water—that is,
that the time consumed in elaborating the first species of land
animals—was much longer than the time which has elapsed since
then. I presume that during a large part of this early period it
would have seemed to one living at that time extremely doubtful
whether there would ever be on the earth any other kinds of life
than the aquatic. And if those who to-day weave the fashionable
fabrics of human philosophy, and who know nothing about anything
outside the thin edge of the present, had been back there, they
would no doubt have declared confidently, as they looked upon the
naked continents and the uninhabited air and the sea teeming with
its peculiar faunas, that life upon solids or in gases, life
anywhere, in fact, except in the sea, where it had always existed,
and to which alone it was adapted, was absolutely, and would be
forever, impossible; and that feathered fishes and fishes with the
power to run and skip, and especially ‘sharks’ competent to walk
on one end and jabber with the other, were unthinkable nonsense.
Life originated in the sea for the same reason that the first of the
series of so-called ‘civilisations’ which have appeared in human
history sprang from the alluvium of the Euphrates and the Nile,
because the conditions for bringing life into existence were here
the most favourable. The atmosphere was incompetent to perform such
a task as the inventing of _protoplasm_ and there was no land above
the oceans.
The first forms of life were one-celled—simple, jelly-like dots of
almost homogeneous plasm—the _protozoa_. These primitive organisms
were the common grandparents of all beings. From them evolved,
through infinite travail and suffering, all of the orders, families,
species, and varieties of animals that to-day live on the earth, and
all those that have in the past lived and passed away. By the
multiplication and specialisation of cells, and the formation of
cell aggregates, the sponges, celenterates, and flat worms were
developed from the protozoa.[1] The connecting links between the
one-celled and the many-celled animals consist of a series of
colonial forms of increasing size and complexity, some of which may
be found in every roadside ditch and pool, while others are extinct.
The development of these many-celled organisms (metazoa) from
one-celled organisms was a perfectly natural process, a process
which takes place in the initial evolutions of every embryo. There
is no more mystery about it than there is about any other act of
association. All association is simply a matter of ‘business.’
Many-celled organisms are colonies, or societies, of more or less
closely co-operating one-celled organisms, and they have come into
existence in obedience to the same laws of economy and advantage as
have those more modern societies of metazoa known as nations,
communities, and states, the organised bodies of men, ants, and
millionaires.
The sponges are the lowest of the many-celled animals. They consist
of irregular masses of loosely associated cells, hopelessly anchored
to the sea-floor. They represent the social instinct in embryo. The
cells are but slightly specialised, and each cell leads a more or
less independent existence. The sponge stands at about that stage of
social integration and intelligence represented by those stupendous
porifera which cover continents and constitute the ‘social
organisms’ of the civilised world. The nutritive system of sponges
consists of countless pores opening from the surface into a common
canal within, through which ever-waving cilia urge the alimental
waters. In the celenterates the cells arrange themselves in the form
of a cup with one large opening into and from the vase-like stomach.
The unsegmented worms are flat and sac-like, with bilateral symmetry
and the power to move about, but not tubular, as are the true worms.
They are bloodless, like the celenterates and sponges.
From the flat worms developed the annelid worms, animals perforated
by a food canal and possessing a body cavity filled with blood
surrounding this canal. The body cavity is the space between the
walls of the body and the alimentary canal, the cavity which in the
higher animals contains the heart, liver, lungs, kidneys, etc. The
worms and all animals above them have this cavity. The worms and all
animals above them also have, as an inheritance from the flat worms,
bodies with bilateral symmetry—that is, bodies with two halves
similar. This peculiarity was probably acquired by the flat worms,
and so fastened upon all subsequently evolved species, as a result
of pure carelessness. It probably arose out of the habit of using
continually, or over and over again, the same parts of the body as
fore and aft. It has been facetiously said that if it had not been
for this habit, so inadvertently acquired by these humble beings so
long, long ago, we would not to-day be able to tell our right hand
from our left. In the worm is found the beginning of that wonderful
organ of co-ordination, the brain. The brain is a modification of
the skin. It may weaken our regard for this imperial organ to know
that it is, in its morphology, akin to nails and corns. But it will
certainly add to our admiration for the infinite labours of
evolution to remember that the magnificent thinking apparatus of
modern philosophers was originally a small sensitive plate developed
down in the sea a hundred million years ago on the dorsal wall of
the mouths of primeval worms.
From the worms developed all of the highest four phyla of the animal
kingdom—the echinoderms, the mollusks, the arthropods, and the
chordate animals, the last of which were the progenitors of the
illustrious vertebrates. The lowest of the mollusks are the snails,
and from these humble tenants of our ponds and shores sprang the
headless bivalves and the giant jawed cuttles. The mollusks were for
a long time after their development the mailed monarchs of the sea,
and shared with the worms the dominion of the primordial waters. But
after the development of the more active arthropods, especially the
crustaceans, the less agile worms and mollusks rapidly declined.
Existing worms and mollusks are remnants of once powerful and
populous races.
From the worms also developed the arthropods, the water-breathing
crustaceans and the air-breathing spiders and insects. The
crustaceans came early, away back in the gray of the Silurian
period, just about the time North America was born. North America
lay, a naked, V-shaped infant, in the regions of Labrador and
Canada. The crustaceans rapidly superseded the mollusks as rulers of
the sea, attaining, in extreme species, a length of four or five
feet. The spiders and Insects came into existence toward the latter
part of the Silurian period,[1] probably contemporaneous, or nearly
so, with the appearance of land vegetation. The spiders and insects
were the aborigines of the land and air. They are the only races of
living beings, except the original inhabitants of the sea, who ever
invaded and settled an unoccupied world. The earliest land fossils
so far found are the fossils of scorpions. But the existence of a
sting among the structural possessions of these animals indicates
that there were already others who contended with them for supremacy
in the new world. The first insects were the masticating insects,
insects such as cockroaches, crickets, grasshoppers, dragon-flies,
and beetles. They are found abundantly in the Devonian and
Carboniferous rocks. The licking insects (bees) and the pricking
insects (flies and bugs) appeared first in the Mesozoic Era, and the
sipping insects (butterflies) in the Cenozoic. The flower-loving
insects (the bees and butterflies) came into the world at the same
time as did the flowers. The wings of insects may be modifications
of the gills used by insect young in respiration during their
aquatic existence. They are, hence, very different in origin from
the wings of birds, which are the modified fore-legs of reptiles.
The most important class of animals arising out of the worms, on
account of their distinguished offspring, were the hypothetical cord
animals. The only existing species allied to these animals is the
amphioxus, a strange, unpromising-looking creature, half worm and
half fish, found in the beach sands of many seas. It has white blood
and a tubular heart. It is without either head or limbs, and looks
very much like a long semitransparent leaf, tapering at both ends.
But it has two unmistakable prophecies of the vertebrate anatomy: a
cartilaginous rod, pointed at both ends, extending along the back,
and above this, and parallel to it, a cord of nerve matter. These
are the same positions occupied by the spinal column and spinal cord
in all true vertebrates. That the amphioxus is a genuine relative of
the ancestor of the vertebrates is also shown by the fact that these
simple forms of column and cord possessed by amphioxus are precisely
the forms assumed by the spinal column and spinal cord in the
embryos of all vertebrates, including man.
From these quasi-vertebrates developed the fishes—first (after the
scaleless, limbless lampreys) the sharks with spiny scales and
cartilaginous skeleton, and after these the lung fishes and the bony
fishes, with flat, horny scales and skeletons of bone. From the
beginning of the Devonian age, when fishes first came into
prominence, till the rise of the great reptiles in the Triassic
time, fishes were the dominant life of the sea. In the fishes first
appeared jaws, a sympathetic nervous system, red blood, backbone,
and the characteristic two pairs of limbs of vertebrates.
The lung fishes (Dipneusta), a small order of strange
salamander-like creatures which live ingeniously on the borderland
between the liquid and the land, may be looked upon as
physiological, if not morphological, links between the fishes and
the frogs. They combine the characters of both fishes and frogs, and
zoologists have been tempted to make a separate class of them, and
place them between the two classes to which they are related. They
are like fishes in having scales, fins, permanent gills, and a
fish-like shape and skeleton. They resemble frogs in having lungs,
nostrils, an incipiently three-chambered heart, a pulmonary
circulation, and frog-like skin glands. There are three genera with
several species. One genus (Neoceratodus) is found in two or three
small rivers of Queensland, Australia; another (Protopterus) lives
in the Gambia and other rivers of Africa; and the third
(Lepidosiren) inhabits the swamps of the Amazon region. They all
breathe ordinarily by means of gills, like true fishes, but have the
habit of coming frequently to the surface and inhaling air. The
air-bladder acts as an incipient lung in supplementing respiration
by gills. They all live in regions where a dry season regularly
converts the watercourses into beds of sand and mud. During the
season of drought these strange animals build for themselves a
cocoon or nest of mud and leaves. This cocoon is lined with mucus,
and provided with a lid through which air is admitted. Here they lie
in this capsule throughout the hot southern summer, from August to
December, breathing air by means of their lungs and living upon the
stored-up fat of their tails, until the return of the wet season,
when they again live in the rivers and breathe water in true
piscatorial fashion. These capsules have often been carried to
Europe, and opened 3,000 miles from their place of construction
without harming the life within.
Here, in these eccentric denizens of the southern world, we find the
beginnings of a grand transformation—a transformation in both
structure and function, a transformation made necessary by the
transition from life in the water to life in the air, a
transformation which reaches its maturity in the higher
air-breathing vertebrates, where the simple air-sac of the fish
becomes a pair of lobed and elaborately sacculated lungs, performing
almost exclusively the function of respiration, and the gills change
into parts of the ears and lower jaw.
The air-bladder of ordinary fishes, which is used chiefly as a
hydrostatic organ to enable the fish to rise and fall in the water,
is probably the degenerated lung of the lung fishes.
From the lung fishes or allied forms developed the amphibians, the
well-known fish quadrupeds of our bogs and brooks. The amphibians
are genuine connectives—living links between the life of the sea
and the life of the land. In early life they are fishes, with gills
and two-chambered hearts. In later life they are air-breathing
quadrupeds, with legs and lungs and three-chambered hearts. Here is
evolution, plenty of it, and of the most tangible character. And it
takes place right before the eyes. The transformation from the fish
to the frog is, however, no more wonderful than the embryonic
transformations of other vertebrates. It is simply more apparent,
because it can be seen. The lungs of amphibians and the lower
reptiles are simple sacks opening by a very short passage into the
mouth. Some amphibians, as the axolotl of Mexican lakes, ordinarily
retain their gills through life, but may be induced to develop lungs
and adapt themselves to terrestrial life by being kept out of the
water. Others, as the newts, which ordinarily develop lungs, may be
compelled to retain their gills through life by being forced to
remain uninterruptedly in the water. The black salamander,
inhabiting droughty regions of the Alps, brings forth its young
bearing lungs, and only a pair at a time. But if the young are
prematurely removed from the body of the mother and placed in the
water, they develop gills in the ordinary way. These are remarkable
instances of elasticity in the presence of a varying environment.
In the amphibians the characteristic five-toed or five-fingered
foot, which normally forms the extremities of the limbs of all
vertebrates except fishes, is first met with. It was this
pentadactyl peculiarity of the frog, inherited by men and women
through the reptiles and mammals, that gave rise to the decimal
system of numbers and other unhandy facts in human life. The decimal
system arose out of the practice of early men performing their
calculations on their fingers. This method of calculating is still
used by primitive peoples all over the world. The sum of the digits
of the two hands came, in the course of arithmetical evolution, to
be used as a unit, and from this simple beginning grew up the
complicated system of tens found among civilised peoples. It has all
come about as a result of amphibian initiative. Our very arithmetics
have been predetermined by the anatomical peculiarities of the
frog’s foot. If these unthinking foreordainers of human affairs
had had four or six toes on each foot instead of five, man would no
doubt have inherited them just as cheerfully as the number he did
inherit, and the civilised world would in this case be to-day using
in all of its mathematical activities a system of eights or twelves
instead of a system of tens. A system of eights or twelves would be
much superior in flexibility to the existing system; for eight is a
cube, and its half and double are squares; and twelve can be divided
by two, three, four, and six, while ten is divisible by two and five
only.
How helpless human beings are—in fact, how helpless all beings
are! How hopelessly dependent we are upon the past, and how
impossible it is to be really original! What the future will be
depends upon what the present is, for the future will grow out of,
and inherit, the present. What the present is depends upon what the
past was, for the present has grown out of, and inherited, the past.
And what the past was depends upon a remoter past from which it
evolved, and so on. There is no end anywhere of dependence, either
forward or backward. Every fact, from an idea to a sun, is a
_contingent link in an eternal chain_.
From the amphibians (probably from extinct forms, not from living)
there arose the highest three classes of vertebrates—the true
reptiles, the birds, and the mammals—all of whom have lungs and
breathe air from the beginning to the end of their days. Gills, as
organs of breathing, disappear forever, being changed, as has been
said, into parts of the organs of mastication and hearing. In the
reptiles first appear those organs which in the highest races
overflow on occasions of tenderness and grief, the tear glands.
These organs are, however, in our cold-blooded antecedents, organs
of ocular lubrication rather than of weeping. There are but four
small orders of existing reptiles—snakes, turtles, lizards, and
crocodilians. These are the pygmean descendants of a mighty line,
the last of a dynasty which during the greater part of the Mesozoic
ages was represented by the most immense and powerful monsters that
have ever lived upon the earth. Mesozoic civilisation was
pre-eminently saurian. Reptiles were supreme everywhere—on sea and
land and in the air. Their rulership of the world was not so bloody
and masterful as man’s, but quite as remorseless. Imagine an
aristocracy made up of pterosaurs (flying reptiles), with teeth, and
measuring 20 feet between wing-tips; great plesiosaurs (serpent
reptiles) and ichthyosaurs (fish reptiles), enormous bandits of the
seas; and dinosaurs and atlantosaurs, giant land lizards, 30 feet
high and from 50 to 100 feet in length. A government of demagogs is
bad enough, as king-ridden mankind well know, but dragons would be
worse, if possible. The atlantosaurs were the largest animals that
have ever walked upon the earth. They were huge plant-eaters
inhabiting North America. It has been surmised that one of these
behemoths ‘may have consumed a whole tree for breakfast.’ It was
the mighty saurians of the Mesozoic time who brought into
everlasting subordination the piscatorial civilisation of the
Devonian and carboniferous ages.
Toward the latter part of the Reptilian Age, and somewhere along
about the time of the appearance of hard-wood forests, came the
birds, those beautiful and emotional beings who, in spite of human
destructiveness, continue to fill our groves and gardens with the
miracles of beauty and song. The bird is a ‘glorified reptile.’
How the ‘slow, cold-blooded, scaly saurian ever became transformed
into the quick, hot-blooded, feathered bird, the joy of creation,’
is a considerable mystery, yet we know no reason for believing that
the transformation did not take place. Although in their external
appearance and mode of life birds and reptiles differ so widely from
each other, yet, in their internal structure and embryology, they
are so much alike that one of the brightest anatomists that has ever
lived (Huxley) united them both into a single class under the name
Sauropsida. It might naturally be supposed that the birds are
descendants of the flying reptiles, the pterosaurs. But this may not
be true. The pterosaurs were structurally much further removed from
the birds than were certain extinct terrestrial reptiles. The fact
that birds and pterosaurs both had wings has really nothing to do
with the case. For the wings of reptiles, we almost know, were not
homologous with the wings of birds. The bird’s wing is a feathered
fore-leg; the wing of the reptile was an expanded skin stretching
from the much-elongated last finger backwards to the hind-leg and
tail. Wings, it may be remarked in passing, have had at least four
different and distinct beginnings in the animal kingdom, represented
by the bats, the birds, the reptiles, and the insects. This does not
include the parachutes of the so-called flying squirrels, lemurs,
lizards, phalangers, and fishes.
The first birds had teeth and vertebrated tails. The archeopteryx,
which is the earliest toothed bird whose remains have yet been
found, was about the size of a crow. It had thirty-two teeth and
twenty caudal vertebrae. Two specimens of it have been found in the
Jurassic slates of Bavaria. One of these fossils is in the British
Museum, and the other in the Museum of Berlin. Other toothed birds
have been found fossil by Dr. Mudge in the cretaceous chalk of North
America. These last had short, fan tails like existing birds.
From the toothed birds developed the beaked birds—the
keel-breasted birds (the group to which most existing birds belong)
and the birds with unkeeled breasts, _i.e._, the ostrich-like birds.
The ostrich-like birds are runners. They have rudimentary wings, and
the keel of the breast-bone, which in the keel-breasted birds acts
as a stay for the attachment of the wing muscles, is lacking. The
ostrich-like birds are probably degenerate flyers, the flying
apparatus having become obsolete through disuse. The feathers of
birds are generally supposed to be the modified scales of reptiles.
The most brilliant offspring of the reptiles were the mammals,
animals capable of a wider distribution over the face of the earth
than the cold-blooded reptiles, on account of their hair and their
warm blood. Cold-blooded animals of great size are able to inhabit
but a small zone of the existing earth’s surface—the torrid
belt. They cannot house themselves during the seasons of cold, as
men can; nor escape to the tropics on the wings of the wind, as do
the birds; nor bury themselves in subaqueous mud, as do the frogs,
snakes, and crustaceans. During the Mesozoic period, when
cold-blooded reptiles of gigantic size flourished over a wide area
of the earth’s surface, the planet was far warmer than now.
Animals, therefore, like the mammals (or birds), capable of
maintaining a fixed temperature regardless of the thermal
fluctuations of the surrounding media, are the only animals of large
size and power capable of uninterrupted existence over the greater
part of the surface of the existing earth. The pre-eminent life of
the Cenozoic time was mammalian. But the decline and fall of the
saurian power was not wholly due to the rise of the more dynamic
mammals. It was in part due, no doubt, to adverse conditions of
climate, and also to the fact that mammals and birds guard their
eggs, and saurians do not.
The lowest of the mammals are the monotremes, animals which blend in
a marvellous manner the characteristics of birds, reptiles, and
mammals. Only two families of these old-fashioned creatures are
left, the echidna and the duck-bill (ornithorhynchus), both of them
found on or near that museum of biological antiquities, Australia.
They are covered with hair and suckle their young like other
mammals, but they have only the rudiments of milk glands, and they
lay eggs with large yolks from a cloaca, like the reptiles and
birds. The duck-bill hides its eggs in the ground, but the echidna
hatches its eggs in a small external brooding pouch, periodically
developed for this purpose. The young of the monotremes feed on the
oily perspiration which exudes from the body of the mother. The
monotremes first appear in the fossiliferous rocks of the Triassic
Age.
From the monotreme-like mammals developed the marsupial mammals,
animals possessing a purse-like pouch on the after part of the
abdomen, in which they carry their young. The young of marsupials
are born in an extremely immature state, and are carried in this
pouch in order to complete their development. The young of the
kangaroo, an animal as large as a man, are only about an inch in
length when they are born. They are carried for nine months after
their birth in the marsupium of the mother, firmly attached to the
maternal nipple. The marsupials came into existence during the
Jurassic Age, and during the next age, the Cretaceous, they arose to
considerable power. During this latter age they were found on every
continent. But they have been almost exterminated by their more
powerful descendants.
From the marsupials developed the placental mammals, animals so
called because their young are developed within the parental body in
association with a peculiar nourishing organ called the placenta.
From the herbivorous marsupials developed the almost toothless
edentates, the rodents, or gnawing animals, the sirenians, the
cetaceans, and the hoofed animals, or ungulates. The sirenians are
fish-like animals with two flippers, and are often called sea-cows.
They resemble whales in many respects, and are sometimes classed
with them. They are plant-eaters exclusively, and are found grazing
along the bottoms of tropical estuaries and rivers. They have tiny
eyes, teeth fitted for grinding (not spike-like as in the whales),
and a strong affection for their young, the mother, when pursued,
often carrying her little one under her flippers. An immense
sirenian, known as Steller’s manatee, was discovered on the
Behring Islands, along the Kamschatka coast, in 1741. Twenty-seven
years afterwards not one of them was left, all having been murdered
by the Russian sailors. The sirenians are probably degenerate forms
of land quadrupeds, having lost their hind-limbs and developed the
fish-like shape in adapting themselves to aquatic conditions. They
appear first in the Eocene Age.
Among the most interesting derivatives of the herbivorous
marsupials, because the most aberrant, are the whales. They are true
mammals—have warm blood, breathe the air with lungs, and suckle
their young like other mammals. But, like the sirenians, they live
in the surface of the waters, and have flippers and a fish-like tail
and form. They differ from the sirenians, however, in being
carnivorous, in having inguinal instead of pectoral milk glands, and
in being structurally less like quadrupeds. They probably
degenerated from land quadrupeds during the Jurassic period, and,
owing to their longer residence in the waters, have become further
removed from the quadrupedal type than the sirenians. Whales have
two limbs, the hind-limbs having disappeared as a result of the
pre-eminent development of the tail. The tails of whales and
sirenians are flattened horizontally, not vertically, as in fishes.
Out of generalised forms of hoofed animals now extinct developed the
odd-toed and even-toed races of existing ungulates. The original
ungulates had five hoofs on each foot, and were highly generalised
in their structure. From these original five-toed forms have arisen
the variously hoofed and variously structured tribes of existing
ungulates: the five-toed elephant, the four-toed tapir and
hippopotamus, the three-toed rhinoceros, the two-toed camel, sheep,
swine, deer, antelope, giraffe, and ox, and the one-toed horse and
zebra.
The carnivorous branch of the placental animals came from the
carnivorous branch of the marsupials. From early forms of
carnivorous placentals developed the ape-like lemurs and those
generalised forms of rapacious animals from which arose the
insect-eaters, the bats, and the true carnivora. The seals represent
a by-development from the main line of the carnivora, a third
defection, and a comparatively recent one, from land faunas. Seals
live at the meeting of the land and the waters rather than in or on
the waters, as do the cetaceans and sirenians. They have retained
their fur and their four limbs, but have almost lost their power of
land locomotion by the conversion of their feet into flippers. The
two front-limbs of seals are the only ones used as ordinary limbs
are used. The hind-limbs in most seals stretch permanently out
behind, the webbed digits spreading out fan-shaped on either side of
the stumpy tail, and constituting a rowing apparatus functionally
homologous with the tail of fishes and whales. According to Jordan,
the fur seals and the hair seals are descended from different
families of land carnivora, the former probably from the bears, and
the latter from the cats.
The lemurs are of especial interest to human beings, because in them
are found the first startling approximation in looks and structure
to the ‘human form divine.’ The lemurs are monkey-like creatures
living in trees, but differ enough from true monkeys to be often
placed in an order by themselves. Their milk glands are abdominal
instead of pectoral, as in the monkeys, and the second digit of each
hand and foot ends in a claw. The most of them live in Madagascar.
They are generally nocturnal in their habits, although some species
are diurnal. They appear first in the Eocene rocks, and Haeckel
thinks they may have developed from opossum-like marsupials in the
late Cretaceous or early Eocene Age.
From lemurs or from some other similar sort of semi-apes developed
the true apes—the flat-nosed (platyrhine) apes of the New World
and the narrow-nosed (catarhine) apes of the Old World. There is
considerable difference between the New World apes and those of the
Old World. The differences between the two classes is, in fact, so
striking that they are thought by some to have developed
independently of each other from distinct species of semi-apes. The
apes of the New World have flat noses, and the nostrils are far
apart and open in front of the nose, never below. The Old World apes
have narrow noses, the nostrils being close together and opening
downwards as in man. The tail of (nearly) all New World apes is
prehensile, being used regularly as a fifth limb, while among Old
World apes the tail is never so used. The Old World apes all have
the same number and kinds of teeth as man has, while the New World
apes (excepting the Brazilian marmosets) have an additional premolar
in each half-jaw, making thirty-six in all. The catarhine apes are,
therefore, structurally much nearer to man than their platyrhine
cousins. All tailed apes probably sprang originally from a single
stirp of semi-apes, and spread over the earth at a time when the
eastern and western land masses of the southern hemisphere were
connected with each other. The earliest remains of apes appear in
the Miocene Age.
From the Old World tailed apes were developed the tailless,
man-like, or anthropoid apes—the gorillas and chimpanzees of
Africa, and the orangs and gibbons of Asia and the East Indies. The
anthropoids arose from the tailed apes by the loss of the tail, the
thinning of the hairy covering, the enlargement of the fore-brain,
and by structural adaptations to a more nearly vertical position. No
remains of anthropoids are found earlier than the Pliocene Age.
The man-like apes are the nearest living relatives of the human
races. It is not probable that man has been derived directly from
any of the existing races of man-like apes. For no one of them in
all particulars of its structure stands closer to him than the rest.
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. The earliest human races probably sprang from man-like races
of apes now extinct, who lived in southern Asia or in Africa during
the Pliocene Age (possibly as early as the Miocene), and who
combined in their structures the various man-like characters
possessed by existing anthropoids.
The earliest races of men were speechless—the ape-like
‘Alali’—beings, living wholly upon the ground and walking upon
their hind-limbs, but without more than the mere rudiments of
language. The vertical position led to a much greater development of
the posterior parts, especially of the muscles of the back and the
calves of the leg. The great toe, which in the ape is opposable,
lost its opposability, or all except traces of it, after the
abandonment of arboreal life. It must have been a sight fit to stir
the soul of the most leathern, these children of the night, with low
brows, stooping gait, and ape-like faces, armed with rude clubs,
clothed in natural hair, and wandering about in droves without law,
fire, or understanding, hiding in thickets and in the holes of the
earth, feeding on roots and fruits, and contending doubtfully with
the species around them for food and existence.
From the ‘Alali’—the speechless ape-men—we may imagine the
true men to have evolved—talking men, men with erect posture and
mature brain and larynx, the woolly-haired ulotrichi and the
straight-haired lissotrichi. There are four existing species of
woolly-haired men: the Papuans of New Guinea and Melanesia, and the
Hottentots, Caffres, and Negroes of southern, equatorial, and north
central Africa respectively. They all have long heads, slanting
teeth, very dark skin, and black, bushy hair, each individual hair
in cross-section being flat or oval in shape. In the straight-haired
races the skin is much fairer than in the woolly-haired races, being
seldom darker than brown, and each individual hair in cross-section
is round like the cross-section of a cylinder. The principal species
of straight-haired men are the sea-roving Malays of the East Indies
and the Pacific, the round-faced Mongols of eastern and northern
Asia, the aboriginal Americans of the western hemisphere, and the
incomparable Aryans, including the ancient Greeks and Romans and the
modern peoples of India, Persia, and Europe.
Man is to-day the pre-eminent animal of the planet. The successive
ascendancies of the Worm, the Mollusk, the Crustacean, the Fish, the
Reptile, and the Mammal, are followed triumphantly by the ascendancy
of the Children of the Ape.
A large part of the life of the earth has remained steadfastly where
it was cradled, beneath the waves. But more restless portions have
left the sea and crept forth upon the land, or swarmed into the air.
One migration, the most numerous, is represented by the insects.
Another, the most enterprising, was the amphibian. After ages of
evolution the amphibian branch divided. One branch acquired wings
and sailed off into the air. The other divided and subdivided. One
of these subdivisions entered the forests, climbed and clambered
among the trees, acquired perpendicularity and hands, descended and
walked upon the soil, invented agriculture, built cities and states,
and imagined itself immortal. Human society is but the van—the
hither terminus—of an evolutional process which had its beginning
away back in the protoplasm of primeval waters. There is not a form
that creeps beneath the sea but can claim kinship with the eagle.
The philosopher is the remote posterity of the meek and lowly amoeba.
1. See ‘Genealogy of Animals,’ at the end of the chapter.
2. See table of geological ages, at the end of the previous chapter.