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EVOLUTION IN THE PAST

[To fnce Title-page

EVOLUTION

IN THE PAST

HENRY R. KNIPE, F.L.S.

AUTHOR OF "nebula TO MAN"

WITH ILLUSTRATIONS

ALICE B. WOODWARD AND ERNEST BUCKNALL

LONDON
HERBERT AND DANIEL
2 1 MADDOX STREET
W.
1912

H
Saqt

QE
111

PREFACE

In the following pages I have endeavoured to give in non-
technical language, and in some detail, an account of ancient
life as now known and understood. The wider and increasing
interest in the subject is, no doubt, in part owing to many
recent discoveries of important fossil remains. The whole
subject, however, became invested with a new interest as
soon as it came to be recognised that all modern life has been
evolved, step by step, from the life of the past.

The material for bringing ancient life into view is, it must
be admitted, still sadly deficient. Much — and of the highest
value — has been lost ; but, thanks to the labours of hosts
of workers, much has been recovered. Thousands and
thousands of extinct species of life-forms are now recorded ;
and had these not been described and classified, the student
might well have been bewildered at their multiplicity.

Fortunately for him such works as Zittel's " Text Book of
Palaeontology," Nicholson and Lydekker's " Manual of
Palaeontology," and Arthur Smith Woodward's " Vertebrate
Palaeontology " have come to his rescue. These books
represent a prodigious amount of difficult work conscien-
tiously and ably performed ; and they are indispensable to
anyone who seeks to tell the story of life through past ages.

I would also acknowledge great assistance received from
the various Catalogues and Guide Books dealing with fossil
life, which have been issued by the Trustees of the British
Museum. These valuable publications are especially helpful
to an understanding and appreciation of the vast collections
in the Natural History Museum. A full list of the principal

vii

viii

PREFACE

works which I have consulted, and to which I desire to record
my obhgations, will be found in the Appendix.

I have sought to enliven these pages by introducing
restorations of extinct forms of life. Of the fifty-six plate
illustrations fifty-one were especially drawn for this book.
The remaining five first appeared in my " Nebula to Man,"
published in 1905.

I acknowledge with gratitude the valuable expert assistance
which Miss Alice B. Woodward received at the British Museum
(Natural History). Her pictures thus possess a real scientific
value in addition to their artistic merit. Dr. Arthur Smith
Woodward, f.r.s., Keeper of the Department of Geology,
kindly advised on several of the drawings ; and I would especi-
ally mention his help in the restorations of early fishes and
fish-hke life. In regard to that subject I have also to thank
Dr. Ramsay Traquair, f.r.s., whose skilful restorations I
have been permitted to use. Dr. C. W. Andrews, f.r.s.,
rendered very great assistance. Indeed, nearly all the
restorations of reptiles and mammals drawn by Miss Wood-
ward were made under his able supervision. For this kind
help I cannot speak too gratefuUy. In the restoration of the
first known fossil bird (ArchcBopteryx) and the wingless
Cretaceous sea-bird (Hesperornis) Miss Woodward had the
highly qualified assistance of Mr. W. P. Pycraft. Dr. F. A.
Bather, f.r.s., gave valuable advice on Crinoids, Dr. W. T.
Caiman on Eurypterus, Mr. G. C. Crick on Belemnites and
other invertebrates, Mr. W. D. Lang on Sponges, and Mr.
R. B. Newton on some of the shellfishes.

My friend Dr. Henry Woodward, f.r.s., and formerly keeper
of the Department of Geology in the British Museum, not only
gave advice on some of the restorations, but also kindly read
and criticised my typescript. In my final revision I thus
had the great advantage of his observations and suggestions.

H. R. KNIPE.

CONTENTS

pa<;e

Chronology . . . . . . . xv

Introduction . . . . . . . i

Foundational Ages . . . ... 7

PALEOZOIC AGE

Cambrian Period . . . ... 16

Ordovician Period . . . . . . 21

Silurian Period . . . ... 28

Devonian Period . . . ... 38

Carboniferous Period . . . ... 50

Permian Period . . . . . . 6i

MESOZOIC AGE

Triassic Period . . . ... 70

Jurassic Period . . . ... 82

Cretaceous Period . . . ... 98

CAINOZOIC AGE

Eocene Period . . . . . . 116

Oligocene Period . . . . . . 140

Miocene Period , . , . . . 154

Pliocene Period, earlier epoch . . ... 169

Pliocene Period, later epoch . . ... 182

QUATERNARY AGE

Pleistocene Period . . . . . . 189

Present Period . . . . . . 211

APPENDIX

Authorities Consulted . . . . . . 217

General Index . . . ... 227

ILLUSTRATIONS

The plates marked with an asterisk appeared in "Nebula to Man."

Frontispiece . ... Alice B. Woodward

CAMBRIAN PERIOD

PAGE

Marine Invertebrate Life . . . Alice B. Woodward 19

ORDOVICIAN PERIOD
Marine Invertebrate Life . . . Alice B. Woodward 22

SILURIAN PERIOD

Marine Invertebrate Life . . . Alice B, Woodward 34

Ostracoderms . . . . >> ■ 36

DEVONIAN PERIOD
Ostracoderms and Arthrodiran Fishes . Alice B. Woodward 38
Sharks and Ganoids . . . ,, . 40

CARBONIFEROUS PERIOD
Vegetation . . ... Ernest Bucknall 50

Stegocephs . . . . , >> • 59

PERMIAN PERIOD

Pareiasaurus and Inostransevia . Alice B. Woodward 61

Edaphosaurus . . . . >j • 63

Ganoids and Invertebrates . . . „ . 64

TRIASSIC PERIOD
Vegetation . ... Ernest Bucknall 70

Ichthyosaurs . ... Alice B. Woodward 79

JURASSIC PERIOD
* Marine Invertebrate Life . . Alice B. Woodward 86

Vegetation . ... Ernest Bucknall 88

xii

EVOLUTION IN THE PAST

DiPLODOCUS

Stegosaurus

scelidosaurus

Ceratosaurus

Metriorhynchus

Cryptoclidus and Pliosaurus

Flying Lizards

Arch^opteryx

Iguanodon

* Polacanthus
Triceratops

* Pteranodon

* Marine Life
Hesperornis

Alice B. Woodward

Ernest Bucknall
Alice B. Woodward

CRETACEOUS PERIOD

Alice B. Woodward

90 (i)
90 (ii)
92 (i)
92 (ii)
94 (i)
94 (ii)
96 (i)
96 (ii)

98 (i)
98 (ii)

100

104

108

III

Phenacodus

Hyracotherium

coryphodon

Mceritherium

Pal^mastodon

* Arsinoitherium

EOCENE PERIOD

Alice B. Woodward

119
121
122
124
126
130

TiTANOTHERIUM

Hyracodon

Hyopotamus

Vegetation

OLIGOCENE PERIOD

. Alice B. Woodward 141

„ . 142

,, . 144

Ernest Bucknall 152

MIOCENE PERIOD

Pliopithecus

. Alice B.

Woodward

154

Mach^rodus

• • • »>

>»

156

Altecamelus

• • • >»

158

Tetrabelodon

»»

160

PLIOCENE PERIOD

HiPPARION

. Alice B.

Woodward

169

DiNOTHERIUM

• • • >>

>»

171

Cervus Sedgwicki .

' • »»

183

Megatherium

»»

185

ILLUSTRATIONS

Xlll

PLEISTOCENE PERIOD

Pithecanthropus

Elasmotherium

Mammoth

Homo Mousteriensis

HiPPIDIUM

d^edicurus
Macrauchenia
Diprotodon .

Alice B. Woodward

187
189
191
196
203
204
206
208

TEXT-FIGURES

Monobia (p. 9), Morula (p. 10), Blastosphere (p. 10), Gastrula (p. 11).

CHRONOLOGY OF THE EARTH

B.C.

Collision between extinct heavenly bodies, and forma-
tion of the Nebula . . ...

Concentrations in the Nebula, and emergence of the
Earth as a molten body . ...

Long Ages of intense heat of the whole Earth .

Surface of the Earth so far solidified as to support
vast seas . . ...

Foundational Ages extending over 70,000,000 years.

Beginning of Cambrian Period
,, Ordovician Period

,, Silurian Period .

,, Devonian Period

,, Carboniferous Period

,, Permian Period .

,, Triassic Period .

,, Jurassic Period .
,, Cretaceous Period

,, Eocene Period .

,, Oligocene Period

,, Miocene Period .

,, Pliocene Period .

,, Pleistocene Period

,, Present Period .

Palaeozoic Age-

Mesozoic Agre

Cainozoic Age

Quaternary Age

100,000,000

30,000,000
24,500,000
18,000,000
15,000,000
13,000,000
7,500,000

7,000,000
5,750,000
3,500,000

2,250,000
1,750,000
1,250,000
400,000

200,000
50,000

(The estimate of the relative durations of the Periods is founded on the thicknesses of
the successive geological strata. All dates are conjectural, and the above duration must
be regarded as a minimum.)

EVOLUTION IN THE PAST

INTRODUCTION

The conditions under which life first became manifest on
earth are quite unknown. All attempts to reproduce them
have failed ; and even if the conditions, or likely conditions,
were ascertained, the mystery of life would not be solved.
Indeed all phenomena present unfathomable problems, and
man in pursuit of knowledge must needs limit the range of
his researches. Wide fields, however, still are left him ;
and in his endeavour to trace the steps by which life, once
initiated on earth, attained its present development, he
has not been unrewarded.

No one supposes that life, when it first appeared on the
globe, presented, as now, a series of graduated forms, ranging,
from specks of animated matter to human beings. It is felt
that life-forms of simple type must have come first ; and
that these were followed in orderly sequence by organisms
becoming less and less simple, until in time forms of high and
of ever-increasing complexity appeared.

The doctrine of Evolution that the higher organisms have
been evolved step by step from lower organisms is now
generally accepted. The thought that life had developed in
some such continuous and connected manner dawned on the
mind of man centuries ago ; and Aristotle, Lucretius, and
other ancient writers gave vague expression to it. In recent
times Goethe, Erasmus Darwin, and Lamarck all believed in
Evolution, and enunciated clear ideas on the subject. They
had, however, no convincing evidence to offer. This, as the
result of long and patient observation, was supplied by

EVOLUTION IN THE PAST

Charles Darwin, and he will ever be remembered as
having first placed the doctrine of Evolution on a sound
basis.

The Evolution doctrine receives strong support from facts
ascertained in the study of embryos. Organisms in their
embryonic condition pass through stages in which they
resemble the young of animals lower in the scale of life. A
rabbit, for instance, in its immature condition passes through
a stage in which it resembles a young reptile. Rudimentary
organs also make a transitory appearance. Gill-clefts, for
instance, appear in the embryonic history of all the higher
animals. This takes the latter at least as far back as am-
phibians. And amphibians in their embryonic growth pass
through stages in which they resemble fishes. These em-
bryonic phases are only explainable on the hypothesis that,
in the origination of higher animals, lower animals took a
direct ancestral part.

The doctrine of Evolution is also supported by evidence
brought to light from the geological strata. Innumerable
fossils have been found testifying to successive developments
undergone by hfe in the course of past ages. Evidence of
this direct nature — incomplete though it is — is of the greatest
help. The sequence of hfe thus revealed is quite in accordance
with an evolutionary process — the lower forms preceding the
higher. And remains of numerous animals are found com-
bining features that became distributed in later forms.
Phenacodus of the Eocene, for instance, was more or less
closely related to deer, pigs, tapirs, horses, and carnivores.
Then remains of toothed birds with long Hzard-like tails
have been exhumed (Archceopteryx), showing that early bird
life retained some very remarkable affinities with reptiles.
Pedigrees of particular animal forms have also been recovered.
The ancestral history of elephants, for instance, would be a
matter for speculation but for fossil evidence.

Existing life also makes important contributions. In the
light of comparative anatomy creation is certainly more
suggestive of an organic whole than of an assemblage of
independently formed types. Small organisms are found
that cannot be classed satisfactorily either as plants or as

INTRODUCTION

animals (e.g. Volvox). Plants are divided into Cryptogams
and Phanerogams ; but the latter retain characters pointing
to their descent from the former ; and all recent study tends
to bring the two groups very closely together. The various
classes of Invertebrates present connecting links. Many
forms, for instance, of very different outward appearance —
crustaceans, spiders, scorpions, etc. — point to a remote
common ancestry, the members of which must have re-
sembled ringed worms. Then there are animals that cannot
properly be classed either as vertebrates or invertebrates
(e.g. Balanoglossus), and these show affinities with the fish-
like Lancelet, the lowest vertebrate now in existence. Fishes —
especially lung fishes — show affinities with amphibians;
whilst amphibians are closely related to the lizard-like
reptile known as Sphenodon. Birds retain several reptilian
features in their anatomy — some peculiarly so (Opisthocomus
cristatus, Palamedea cornufa). And the lowest forms of
mammals (Monotremes) reveal in their ribs and other parts
of their structure reptilian features not found in animals of
higher grade.

Thanks to Charles Darwin, Russel Wallace, Huxley,
Spencer, Haeckel, Weismann, Cope, and other hard workers
in the fields of Biology, the doctrine that higher life-forms
have been evolved from lower may now be said to have
passed out of the region of controversy. It must, however,
be admitted that many subsidiary problems of descent and
inter-relationship remain as yet unsolved.

All forms of life, therefore, that now abound may be
regarded as having come down, through inconceivably long
vistas of time, from an ancestry of minute one-celled or-
ganisms, possessing a power to vary. At some very remote
period this innate power became manifest in two distinct
directions by the appearance of minute plants and minute
animals. From these humble divergent forms, through
innumerable variations in the past, the whole of existing
plant and animal life has gradually obtained its present con-
dition of development. The power to vary possessed by the
earliest organisms must have been enormous. How they came
to be thus endowed is beyond the reach of knowledge.

EVOLUTION IN THE PAST

Inter-struggle in localities of congestion, temperature,
chemical action, and other forces of environment undoubtedly
prompted the putting forth of variations, but they cannot
have produced the power to vary.

The course of evolution is hard to realise. The difficulty,
however, is lessened by bearing some facts in mind. The cell
is the unit of life ; every organism of whatever degree begins
its existence as a single minute cell ; and all life-forms
above the lowest are cells in combination. All organisms,
therefore — from the highest to the lowest — are in a sense
intimately related.

In the vast majority of cases the initial variations that
led to new forms were probably extremely slight. Organisms
remained much the same as their parents. Important changes,
however, came to be chronicled when small variations of a
useful kind had been accumulated and intensified through a
series of generations. That, at least, is the view that Charles
Darwin propounded ; and it has been accepted by most
evolutionists.

From researches — chiefly botanical — pursued in recent
years by Hugo de Vries and W. Bateson, it has been claimed
that variations not infrequently are of a pronounced character.
It is also claimed — on somewhat fragile evidence — that that
is the usual method whereby new species appear. For such
substantial changes suddenly effected the name of " muta-
tions," also of " explosions " (Deperet), has been given.
There is certainly evidence that developments of this character
take place ; and the fact was admitted by Charles Darwin,
and other evolutionists of the time. It was, however — and
still is — urged that such phenomena very seldom occur ; and
that they are in fact sports and monstrosities that cannot be
perpetuated in wild Nature. Nor has this view been proved
to be incorrect, although Mendel's discoveries show that in
domesticated Nature, mutations, repressed in one generation,
reappear in another.

Although not quite in line with a portion of Darwinism,
the Mutation Theory, of course, does not affect the general
doctrine of Evolution. Should it ever be established — and it

INTRODUCTION

is as yet far from that — Evolution would be proved a some-
what less tardy process than Darwin supposed.

Whatever be the rate at which Evolution proceeds, it is
quite clear that all structural changes, except of the most
trivial description, have sooner or later to submit to a severe
test. To this testing process Darwin gave the name of
Natural Selection. " Survival of the Fittest " — suggested by
Herbert Spencer — has the same meaning.

That Natural Selection applies and must always have applied
to all forms of life was first recognised by Darwin and Wallace.
More organisms may be said to desire to live on earth and to
multiply than can be accommodated ; and which shall survive
must be determined by a principle of selection. In the in-
evitable struggle, all those forms which become the better
adapted to meet the difficulties and dangers that surround
them are the more likely to survive and leave posterity. The
fittest, in short, are selected by Nature for preservation, and
all advantageous variations in development receive encourage-
ment. In this way forms of life are slowly reconstructed,
reshaped, and recoloured ; and in course of time they become
so changed as to present a very different appearance from
that of their remote ancestors. Natural Selection, therefore,
in a sense, may be said to originate species.

This selective system — involving as it does a real progress —
does not imply that organisms of inferior rank necessarily
cease to prosper as forms of higher rank are evolved. Or-
ganisms low down in the scale have proved well able to
contend with their conditions, whilst many superior forms
have failed, and disappeared without leaving descendants.
Small shrimp-like creatures that lived in Cambrian seas are
still represented by unmodified forms generically known as
Nebalia. Those little creatures, therefore, are seen in their
watery haunts to-day, reflected, as it were, from a remote
past. Certain lampshells also give us living pictures of
times long gone (Lingula). Moreover, minute one-celled
organisms are still through sea and land in their millions,
and billions, and myriads of them are probably not very
different from the forms in being when the world was young.
Whilst humble life-forms have thus continued their annals.

EVOLUTION IN THE PAST

stegocephs, dinosaurs, plesiosaurs, toxodonts, amblypods,
and other animals of high organisation have come and
gone.

The following pages are mainly occupied with an attempt
to give a sketch of life, founded on discoveries made in the
geological strata. The record is certainly defective, but
there is the consolation of knowing that we are face to face
with facts.

FOUNDATIONAL AGES

According to the Nebular Hypothesis the solar system
was evolved from a vast gaseous mist or nebula. This rarefied
and intensely heated matter was the outcome, it is supposed,
of a collision between extinct suns or other once-luminous
bodies. In course of time, owing to loss of heat by radiation,
concentrations took place in various parts of the vapour.
And the Earth and other planets gradually emerged as
molten bodies moving round a great central concentration —
the forming sun.

As the result of radiation our planet in time became
so far deprived of heat as to gain a superficial crust or cover-
ing. The heat of the crust, however, must for long have con-
tinued so intense as to be beyond the reach of any rainfall
from the primitive atmosphere.

Owing to continued fall in temperature the crust must
have increased in solidness. And a time came when the lower
levels of the cooled and crumpled surface became the resting-
places of long-pent-up rains, no longer repulsed by an ex-
cessive heat. The Earth had its sea and land.

The heat of both elements was for a long time probably
too intense for life, as man understands it, to become manifest ;
but to what point temperature had fallen when the first
forms of life appeared, is quite unknown. In this connection,
however, it is a matter of interest that plants have been
discovered living in thermal springs of a temperature of
170° Fahr., and in heat of 260° Fahr. some spores have been
found to retain vitality.

Of the earliest life-forms nothing, of course, is known.
They probably originated in the shallow waters of the primeval
seas ; and may well have been excessively minute. Indeed

EVOLUTION IN THE PAST

if similar forms are now in existence no microscope, however
powerful, would be likely to reveal them. Food must have
consisted of simple chemical compounds ; and there is no
reason to think that the organisms disclosed any character-
istics, stamping them either as plants or animals. They may
rather be thought of as a highly generalised stock from which
plants and animals were in course of time to be evolved.
The condition of things was Utopian ; — peace abounded and
equaUty.

Very long times may have elapsed before this primitive
condition of things became varied by the emergence of
definite life-forms. Probably the earliest organisms of distinct
character were minute one-celled plants, possessing no defined
root, stem, or leaf. Here was the foundation laid of the
Kingdom of Plants.

In course of time another divergence from the vague
primeval stock took place ; and minute animals, one-celled
and shapeless, made their appearance. These probably
moved about the shallows without the aid of any definite
locomotive appliances, and subsisted chiefly on their vegetal
cousins. The foundation of the Kingdom of Animals was
laid ; but Utopia was gone.

From the primitive plant-stock, it may be supposed, minute
one-celled growths of a mixed algae and fungus description
in course of time made their appearance. Whilst the minute
animals doubtless became varied chiefly by more active forms
aided in locomotion by tiny thread-like outshoots of the cell.

All plants and animals, no doubt, for long consisted merely
of one-celled organisms. Food could be taken in, and waste
expelled at any part of the surface ; and multiplication
was effected by the cell splitting in two, and each portion
becoming a complete self-sufficing cell. Such forms of life,
indeed, still exist in great abundance.

Life on earth could clearly make no great advance towards
its destined future so long as all organisms remained in a
unicellular condition. It may be assumed, therefore, that in
course of time cases occurred in which the two portions of the
dividing cell did not become completely separated from one
another. And these two-celled forms, by continued multi-

FOUiNDATIONAL AGES

plication and the holding together of successive generations,
led to the formation of cell colonies or confederations. The
foundation of co-operation was thus laid. But although the
principle of union was in evidence, there is no reason to
suppose that any cells, excepting as regards free individual
locomotion, underwent any important change. Each cell
probably continued self-sufficing and carried on life much as
before. Loose confederations of this character are still in
existence (e.g. Monohia confluens).

Monobia confluens, after A. Schneider.
< Highly magnified.)

In course of time some of the colonies no doubt underwent
various changes of form, and some of them came to present a
ball-shaped appearance. But whatever their outward aspect
they must all have had to face the population question.
Cells were multiplying fast, and difficulties must have arisen
from want of organisation among the more or less independent
units. Resort, no doubt, was made to various expedients.
In the case of some colonies the problem was doubtless solved
by secession of cells from the union and the founding of new
colonies. If this had been the only way open, further progress
in life would have been indefinitely postponed, if not actually
imperilled. In the case of some of the ball-shaped colonies,
however, it may be assumed that the cells continued to hold
together ; and the power to vary was put to higher tests.

EVOLUTION IN THE PAST

From this point the development of animal life can be
more closely followed than that of plant hfe. Each cell having^
to support itself, the cells in a ball-shaped colony must have
striven to occupy and retain a surface position so as to be in
contact with the outer world. As cell multiplication increased,
the struggle for outside accommodation must have become
intense, and the cells whose fate it was to lie inside must have
perished and polluted the colony unless an improved economy
could be effected.

Then came the great effort to deal with this congested con-
dition, known in biology as the Mulberry stage (Morula).
The solution ultimately reached is probably represented by
the stage biologically known as the Blatosphere or Bud-hke

Morula Stage. Blastophere (in section).

(Highly magnified.)

stage. Taking this as a guide, the inner cells, by some
unknown process, were forced up to the surface, and the
vacated interior became filled with water. The colony had
now become a small ball-shaped mass overspread with a
single layer of cells.

To what extent this outward-forcing process could be
carried cannot be determined. But rapid cell-multiplication,
no doubt, brought difficulties ; and in some of the colonies
a solution was found of higher character than mere outward
expansion. Not only a physical but a psychical change was
impending. The individual cells or units of the colony had
not as yet shown a disposition to a truly united life. There
was no division of labour ; and " each cell for itself " was, so
to speak, the motto of the colony. A new modus vivendi of a
most startling description was now to be evolved. The

FOUNDATIONAL AGES

theory of it was nothing less than the gradual breaking up
of individual self-sufficiency, and forcing the cells to work
more or less with one another for the common weal of the
colony as a whole. In other words, particular functions were
to be assigned to particular cells ; labour was to be divided ;

Gastrula Stage (highly magnified).
The figures to the right are in section.

egoism (for a time) was to make way for altruism ;
interesting datum in primitive ethics.

The first attempt to this higher life was probably made
amongst colonies from which, in course of time, Sponges
were evolved. At one point in the colony certain ceUs
gradually lost their versatile powers and were more or less
drawn into the interior. As the result of continued indrawal,
a tube or cavity was formed, and the colony thus came to

EVOLUTION IN THE PAST

consist of an outer and inner layer of cells (Gastrula stage).
Some division of labour was impending and in time became
evident. The outer cells gradually took up as their duties
matters of protection, reproduction, and arranging lines of
communication with the interior. These several labours,
however, were not separately discharged by cells of different
character ; for the outer cells in great part retained their
original versatility. The duty of the inner cells was more or
less confined to promoting, by means of little lashes, a flow
of the food-bearing water through the whole body of the
colony. There was, therefore, a certain amount of labour-
division, although of primitive description. As, however,
there was no thorough differentiation and co-ordination of
the cells, the transformed colony lacked individuality.
Even to-day the cells of a sponge are far from being in a state
of complete co-ordination. The porous edifice is not the
residence of an ego.

Sponges of various forms and degrees of organisation
must have made their appearance before the Cambrian times.
Very early in their career they settled down to sedentary
lives ; and it is not supposed that they led to the appearance
of any hfe-forms of higher grade. This line of animal evolution
— savouring somewhat of the vegetable — was not, therefore,
momentous.

Sprung from the same stock as sponges, and for a time, no
doubt, retaining close affinities with them, other organisms
slowly appeared. These transformed colonies gradually
developed into hydras, jellyfishes, corals, sea-anemones,
and allied forms. These animals enjoyed the distinction of
possessing a mouth, opening into a cavity in which digestion
was carried on. This cavity had also duties to discharge
relating to circulation. Nerves — unknown to Sponges — were
in a primitive stage of evolution ; and certain cells became
transformed for stinging purposes. The various cells were,
no doubt, so far co-ordinated as to constitute an individuality.
Altruism, therefore, had resulted in a bigger ego.

The animals never gained the distinction of possessing
either heads or hearts. Becoming more or less sedentary in
habit, they developed roundness of structure — the best

FOUNDATIONAL AGES

symmetry with which quiescent Ufe can confront conditions.
Their stings were probably the organs that first raised, in an.
acute form, the puzzHng problem of pain.

From the primeval colonies which, on separate lines of
evolution, had given rise to sponges, and to stinging animals,
another line was struck destined to lead to far more important
results. This departure was evidenced by creatures which,,
in those remote times, are best classed under the comprehen-
sive appellation of Worms. As the result more or less of
boring into the mud and sands of the shallows, the bodies of
these animals became elongated and two-sided. And although
most forms, no doubt, were of a plump and stumpy aspect,
they presented a very different appearance from the sedentary
and rounded stinging animals. As regards, however, internal
organisation, some of them were probably not greatly in
advance of the latter. In course of time several internal
changes were effected. The channel used at one end as a
mouth became a complete thoroughfare through the length
of the body ; whilst the original stomach-like chamber was
rendered more complex by the formation of a second enclosed
space (cceluni). In this new apartment some of the labours
of the old cavity were carried on, and other functions were
also undertaken. Division of labour — a cardinal feature
of progress — was therefore carried farther.

Some of these more advanced worms were probably expert
swimmers ; but at one period certain of them adopted
sedentary habits. In course of time their descendants became
so sedate that the lower part of the body became fixed in
the ground. Brought to this condition, they developed
outwardly a five - sided and more or less radial symmetry.
These animals formed the parent-stock of the spiny-skinned
creatures (Echinoderms) ; and a certain amount of free
existence was in course of time recovered. Cystids, sea-lilies,
sea-urchins, starfishes, brittle-stars, and sea-cucumbers were
the outcome of this line of Evolution.

Meanwhile other of the worms pursued another evolutionary
course. A well-marked head was developed, a thick muscular
surface was formed on the under-part of the body, and the
scattered nerves underwent a considerable amount of concen-

EVOLUTION IN THE PAST

tration. These animals, it is supposed, gave rise to primitive
molluscs ; and in course of time sea-snails, mussels, nautiluses,
and allied forms made their appearance. These, however,
were the only fruits on this branch of evolution.

Certain of the worms, however, developed more in accord-
ance with primitive promise. The nerves became concentrated
in the head region ; a brain was gradually formed, and real
intelligence dawned in animal life. In some forms — long
sensitive to light only — eyes were slowly evolved. And
these animals were probably the first inhabitants of earth to
see anything of their surroundings.

In course of time some of the worms, in correspondence
with internal modifications, became ringed or segmented
(Annelids) ; and lateral outgrowths were developed for
plodding about the shallows. In ringed worms of marine
habits, worm-life reached its highest level of development.
The head, it would seem, is a more ancient institution than the
heart, for worms never developed what can be called " a seat "
for their affections.

Ringed worms played a great part in Evolution, for it
was from their ranks that important divergences took place.
One line of evolution led to brachiopods or lampshells, and
polyzoans ; another to an arthropod stock, which in course of
time branched out into a variety of forms (trilobites, king-
crabs, shrimps, scorpions, etc.). The pioneers of the several
departures were, no doubt, very small animals of their kind.

How far life advanced in the course of the Foundational
Ages cannot be definitely ascertained. But from scanty pre-
Cambrian remains, and from the known life of the Cambrian,
it may be inferred that invertebrates were represented in all
main departments before that Period commenced. Fishes
must certainly have had remote ancestors in pre-Cambrian
seas, but the ancestral forms are quite unknown. For a long
time they probably bore close resemblance to the unsegmented
worms well on the road to the evolution of the spiny-skinned
animals (Echinoderms).

In the absence of reliable evidence until much later times
it is difficult to speak of the progress of vegetation in the
Foundational Ages. But on its humbler plane it no doubt

FOUNDATIONAL AGES

pursued an evolution similar in character to that of primeval
animals. One -celled self-sufficing little plants multiplied
by sphtting into two. Then in some cases the portions of a
divided cell remained more or less in connection, and aggre-
gates of self-sufficing cells were formed. Then came the spirit
of altruism : cells lost their versatility, and passed into
various combinations severally charged with distinct and
special duties for the benefit of the plant colony as a whole.
And under this higher system, roots, stems, and leaves were
gradually evolved.

Long before the Cambrian times, the minute one-celled
growths of mixed fungus and algae description, had given
rise, no doubt, on two separate lines of evolution, to funguses
and algse. From the fungus line it is not supposed that any
plants were derived of higher type than funguses. That
excursion, therefore, from the primitive fold was not more
productive in its way than the Sponge line of evolution in the
animal world.

The minute algae had a momentous part to play. In course
of time some of them developed into seaweeds of various
kinds ; others, spreading to fresh water, gave rise in time to
land-plants. Some of these in the Foundational Ages may
well have reached an organisation not far short of that of
liverworts. Indeed, from some such stock, some small growths
with mixed affinities to ferns, " horsetails," and club-mosses
may already have arisen.

But whatever were the levels reached by Evolution, there is
no doubt that life, first manifested on Earth as mere specks
of animated matter, made great advances in the course of
the long-lasting Foundational Ages. The Cambrian world,
therefore, meets us, not as a sudden creation, but as the
outcome of millions of years of ceaseless evolution.

PALEOZOIC AGE

CAMBRIAN PERIOD

The seas in Cambrian times, no doubt, spread far more
extensively than now ; but probably only the shallows
and moderate depths were as yet the haunts of marine
life.

Tiny one-celled plants and animals must have abounded in
the waters. As to this, however, it is not likely that proof,
except of a meagre description, will ever be forthcoming.
PROTOZOANS The evidence as to seaweeds is extremely doubtful ; but
remains of some minute one-celled animals, that had for
purposes of protection secreted particles of hard substance,
have been brought to light. Some of these microscopic
creatures were foraminifers or " aperture-bearers " — the
name having reference to perforations in the body-covering,
affording outlet for fine threads used in locomotion, and as
food-collectors (Cristellaria). Others — sphere-shaped crea-
tures— with minute flinty skeletons were probably radio-
larians {Sphceroidea).
SPONGES Sponges were in the seas, and in some variety. Certain
transformed cells, it is clear, had long been at work in the
flabby objects for the purpose of providing hard internal
supports. Flinty material had been collected, and worked up
into needles or spicules from the various centres of secretion.
These structures, according to the canal system of the sponge,
took various shapes. Originally they developed, no doubt, as
tiny rods ; but, in course of time, by throwing out cross-
rays, they became four-rayed and six-rayed. Sponges, thus
fortified, were certainly living in the Cambrian (Protospongia,
ArchcBoscyphia). Two well-known existing groups of Sponges
were, therefore, already in being (Hexactinellids, Tetracti-

CAMBRIAN PERIOD

nellids). The work, however, had not ended in spicule-making.
In some cases the spicules were artistically joined together,
forming a beautifully outlined framework. The builders
were, therefore, artists as well as artisans.

Jelly-fishes have left impressions of their flimsy shapes jelly-fishes
(Medusites). Corals were in the waters, and were widely corals
distributed (Archaocyathus) ; but no reef-builders had yet
made their appearance. Some forms, however, allied to corals
were living in more or less large colonies (Cladophora). The CLADOPHORA
majority of these communities were rooted to the ground on a
stem, and the zooids or individuals were borne on one side
(only) of numerous branches and branchlets (Bryograptus).
Other colonies enjoyed a somewhat free existence, and floated
about attached by threads to seaweeds (Dictyonema). The
zooid-communities of our own time, known as " sea-firs " (Ser-
tularians), retain close aflinities with these ancient colonies.

Little bud-shaped animals, rooted in the sea-floor, were CYSTIDS
numerous. The box or cista which contained their vitals
was protected by tiny plates rudely arranged, and rendered
prickly by a deposit of lime. These little creatures — known as
cystids — were not, as a rule, provided with arms (Protocystis,
Stromacystis), and were therefore short of the facilities for
obtaining food which later cystids generally possessed.
Cystids, no doubt, dated far back into the Foundational
Ages ; for a few closely allied but more highly organised
forms, known as crinoids or " sea-lilies," were living in sea-lilies
Cambrian seas (PalcBocrinus). The " spiny-skinned " stock
was also represented on another line of evolution. Star- starfishes
fishes were a fruit of this departure (Palesterina). For long
periods during the Foundational Ages starfishes were probably
— like their cousins the cystids and " sea-lilies " — fixed to the
ground ; but by a gradual wasting away of their stalks
emancipation was in course of time obtained. The arms or
rays of the Cambrian starfishes do not appear to have been
so sharply defined as in later forms ; and the animals, no
doubt, had other peculiar features. So far as is known no
animals in Cambrian seas had become so far developed as to be
describable as sea-urchins (echinoids); but sea-cucumbers
(holothurians) were probably in existence (Eldonia).

EVOLUTION IN THE PAST

WORMS

LAMPSHELLS

BIVALVED
MOLLUSCS

UNIVALVED
MOLLUSCS

CEPHALOPODS

Worms, no doubt, were abundant ; but there is little
evidence of their existence beyond the marks of their trails
and burro wings.

Among the most flourishing animals were the brachiopods
or lampsheUs. These creatures were enclosed in two-valved
shells, more or less lamp-like in outUne. Some of them lived
almost buried in the sand (Lingula), and their line has lasted
till now. The majority, no doubt, passed their lives clinging
to rocks by means of a muscular stalk protruded through the
shell-valves. Brachiopods may have been the first animals to
possess the semblance of a heart. At some period in their
career their heads — except the mouth — certainly disappeared.
In a rock-clinging existence, an improved circulation, it
may be supposed, was a greater boon than a head-piece.

The shells of the brachiopods were in different stages of
evolution. In the simplest forms the valves were not fur-
nished with a hinge {Paterina, Oholella). Neither was there
a special opening for the protrusion of the stalk ; and for its
outlet, therefore, the valves must always have been gaped to
a certain extent. Other brachiopods were more securely
ensconced, as there was a special aperture through which the
stalk was protruded (Discinolepis, Kutorgina). The shell-
valves, moreover, of these animals could be opened and closed
with far greater precision owing to the presence of a hinge,
regulated by teeth and sockets. This mechanical contrivance
— the earliest known piece of machinery in Nature — enabled
the animals to offer a very firm resistance to would-be in-
truders.

The rocks were also the abiding-places of some forms of
bivalved molluscs — primitive mussels and arksheUs (Modio-
loides, Glyptarca). Here also were hard-clinging univalves,
shelled like modern limpets (Scenella). Other gastropods,
some in ramshorn shells, some in shells of periwinkle shape,
crawled about the shallows (Raphistoma, Holopea). Free-
swimming forms ghded through the waters, but their shells
were not of the pattern of any " winged " snails now hving
(Hyolithes). Cephalopods related to the Nautilus were also
on the scene. Their shells, however, in being either straight
or but slightly curved, were very different from the tightly

Pcilesterma

CAMBRIAN MARINE LIFE

To face fngc ig

CAMBRIAN PERIOD

coiled encasements of their now living relations (Orthoceras,
Cyrtoceras).

Exceedingly numerous and widespread were trilobites — trilobites
crusted animals with the body-covering segmented, and
thrice-ridged from head to tail. They lived more or less in
large companies in muddy waters, and were apparently the
first animals to live gregariously. They varied greatly in
size ; the smallest being but as grains of sand ; whilst the
biggest were broad-shouldered, and measured as much as
eighteen inches in length (Olenellus, Paradoxides). Some were
endowed with eyesight ; but many, having taken to a life
beneath the mud, had become blind. A few forms appear
to have been able to roll themselves up in woodlice fashion.

Small kindred forms were well shielded on the anterior primitive
part of the body, and possessed spike-like tails (Aglaspis). king-crabs
In development they appear to have been intermediate
between trilobites and king-crabs, and gave promise, there-
fore, of a new group of animals. Some small scorpion-like
forms (Eurypterids) were also in the waters (Redlichia, sea-
Strabops). SCORPIONS

Species of ostracods were to be seen (Primitia, Entomidella), ostracods
and primitive barnacles. Small phyllopods were also abroad, barnacles
resembling the modern Apus — a relation of water-fleas. phyllopods

Yet other crustaceans were long-tailed and shrimp-Uke in shrimp-like
appearance, with the fore part of the body enclosed in a bent forms
hood-like carapace (Hymenocaris). These little creatures had,
no doubt, descended from the same stock as the phyllopods ;
and they were probably ancestral forms of the higher crusta-
ceans of later times. Of animals now living the small shrimp-
like Nebalia retains the closest affinities with them, and may,
therefore, be regarded as one of the " old blood " of marine
society. Some allied forms had pod-shaped carapaces ; and
have, therefore, been termed pod-shrimps {Caryocaris).

Marine invertebrate life was, therefore, well represented
in the Cambrian ; but, in spite of a never-ceasing Evolution,
the times were not exciting. Animals for the most part
lived either buried in the mud, or rooted to the ground,
or clinging in close-drawn shells to briny rocks. Such as
indulged in locomotion moved about in most cases very slowly.

EVOLUTION IN THE PAST

Hearts were scarcely formed. In many groups there were no
separate sexes. Brains were rare, and headless life abounded.
Indeed, so far as evidence goes, the little shrimp-like forms
and the winged snails alone relieved the prevailing inertia.
LAND LIFE The rocks tell nothing of life on land, and, so far as is
known, it breathed as yet only in the waters. But there
can be little doubt that a humble land - vegetation was in
process of development. Some forms of algse from salt and
fresh waters may well have crept over the land, and even
found their way to far up-country scenes. Indeed, funguses,
liverworts, and even club-mosses and " horsetails " of primi-
tive character, may have flourished far and wide ; for, to
judge by the plants of subsequent Periods, many steps must
have been taken before the close of the Cambrian in the
evolution of a land- vegetation. Possibly the land air was
still unfit for animal breathing ; but the carbon-absorptions
of plant-life were slowly rendering it less choking and op-
pressive.

Long gone though be the Cambrian world, its scenery is not
wholly past recall. There can have been nothing peculiar
in the appearance of the sea ; for, however much its in-
habitants have changed, the general aspect of its waters must
have been the same as now. Nor can the landscapes have
been very different from scenes still to be found in many
regions of the Earth ; — vast ranges of mountains, active
volcanoes, wide rivers rushing along laden with sediments ;
and hill-sides, valleys, and plains scantily clothed with a
fiowerless vegetation.

The air, no doubt, was excessively humid ; and thick
mists must have been frequent over land and sea. As regards
life it was a world of silence ; for the stillness was broken
only by tempests, volcanic eruptions, and other disquietudes
of inanimate Nature.

PALEOZOIC AGE

ORDOVICIAN PERIOD

Life in Ordovician times exhibited many developments, but
none of a sensational character. Remains have been found
of seaweeds in part lime-hardened, as is the case with Coral-
line seaweeds of our own time (Solenopora, Rhabdoporella),
and giant forms of Laminaria were also in existence.

Sponges were extending their range {Protospongia sponges
fenestrata, etc.), and were larger, as a rule, and more
graceful than their Cambrian ancestors. Corals, simple CORALS
{Sireptelasma) and compound (Columnaria, Cyathophyllum),
were numerous, and apparently possessed but trifling differ-
ences from some corals now living. The creatures, as a rule,
appear to have been in thick-walled, non-porous cups ; and
in the compound forms there was, therefore, an absence of
that free circulation which characterised many colonies of
later times. No reefs, it would seem, had yet been formed.
A few colonies — apparently Alcyonarians — were now to be
seen (Heliolites, Syringopora). These probably were fore-
runners of blue corals (Helipora), " sea-fans " (GorgoniidcB),
and Organ-pipe coral (Tubipora).

Colonies related to corals and of " sea-fir " type were grapto-
here much as those of the Cambrian. New colonies, how- lites
ever, known as Graptolites, now come into view. These,
no doubt, were related to the older colonies (Cladophora),
but had become distinguishable by several modifications.
The branching framework of the colony was somewhat
stronger, and able to bear a double-rowed population. Vari-
ous shapes were also developed so as to afford the tiny indi-
viduals greater facilities for obtaining food. Fixed existence
— characteristic of the earlier colonies — had also ceased.

EVOLUTION IN THE PAST

Some drifted about on pieces of seaweed (Phillograptus,
Didymograptus) ; others having developed a disc to act as
a float — and looking like attenuated brittle-stars — had be-
come free of adventitious support (Dichograptus). Such
colonies, however, were no doubt more or less at the mercy
of the currents ; for it is not likely that the zooids had
developed a central navigating authority. The colony had
freedom, but was without any organised abihty to regu-
late it.

GraptoUtes attained an extraordinary development during
this Period. They seem to have been collected often in large
companies, and to have thriven best in muddy waters.
Widespread also was their range ; for traces of them have
been found in Europe, America (North and South), and
Australia.

CYSTIDS The little bud -like cystids showed some progress over
their Cambrian ancestors. The plates of the body-covering
were more symmetrically arranged ; and the animals could
better withstand the pressure of sea-currents (Echino-
sphcera, Cryptocrinus). Many of them were now provided
with small "arms," and enjoyed, therefore, greater facilities
for obtaining food. This was no small gain for animals
rooted to the ground, and incapable, therefore, of pursuing
prey. No stems, at least of any note, had as yet been de-
veloped ; and the round little creatures — seldom bigger than
walnuts — must have had a squat and dumpy appearance
beside their near relations, the " sea-lilies."
SEA-LILIES Crinoids, or " sea-lilies " — scarce in the Cambrian — were
variously developed, and easily first among the beauties
of the sea. Some, indeed, had their " arms " bare
and feebly developed, but they were by no means devoid
of grace. The arms of many, however, were long, finely
formed, and edged with feathery out-shoots (Glyptocrinus,
etc.). Utility, of course, was the object, and beauty had
come by the way. Long arms gave good reach for food,
and feathery appendages were useful for sweeping the supplies
down to the mouth, and also for aiding respiration. A few
forms had undergone changes which, no doubt, greatly
added to their enjoyment of Ufe {Ichthyocrinidce). With all

(Ceraurus)

ORDOVICIAN MARINE LIFE [To face page

ORDOVICIAN PERIOD

STARFISHES

BRITTLE-
STARS

SEA-URCHINS

crinoids save these, the mouth of the animal was not exposed
to view, but concealed under a disc of little plates stretching
across the top of the cup. By this arrangement food brought
down by the arms was conveyed to the mouth through
small tubes or passages under the disc. In the case of these
particular crinoids the mouth was brought into view by dis-
placement of the discal plates, and the tubes were superseded
by surface channels. The animal could thus take in food
more freely, and of larger size ; and in course of time
muzzled crinoids all passed away.

Starfishes, owing to reduced discs, and more sharply
defined arms, were now moving about more freely (Palceaster).
But their numerous little tube-feet were not so well protected
as those of later forms. Brittle-stars attested new develop-
ments. Some of these creatures possessed far more flexible
rays than the starfishes (Protaster) — owing, no doubt, to the
digestive system having become centralised in the disc, and
not extending, as with starfishes, into the rays. Echinoids or
sea-urchins — unknown in the Cambrian — were certainly now
abroad. These Ordovicians — ^harbingers of a multitudinous
and widespread race — were about the size of cherries ;
and their bristling body-coverings were more economically
constructed than those of any later urchins (Bothriocidaris).

Here and there in chalky tubes, cemented to the rocks, WORMS
certain worms (Ortonia) swelled the ranks of stationary life —
already considerable.

Among the shelly hosts cemented existence was also
noticeable, — some very small lampshells having developed
the less laborious method of clinging to rocks (Crania).
The vast majority of lampshells, however, retained their
mobility — such as it was — unimpaired. Many of these
recalled the forms that hved and died on Cambrian coasts.
Those, however, in hinge-worked shells had greatly increased ;
and in some cases their shells were strengthened with ribs
(Platystrophia, etc.). Their less inventive brethren neverthe-
less were still numerous. Certain of the more advanced
forms had also developed a lime framework for the " arms,"
so that the food-bearing water near the mouth could be
better kept in motion (A try pa, Rhynchonella). In later times

LAMPSHELLS

EVOLUTION IN THE PAST

this modification brought great rewards in the lampshell
competitions for survival.
BIVALVED, Bivalved molluscs do not seem to have greatly increased :

MOLLUSCS nor were they very widely distributed. There was, however,
a little more variety in their ranks, for some were now in view
with flaps to their shells {PterineidcB), as with the wing-shells
of our own time (Avicula). This development, no doubt,
provided the hinge with an extra strong basis ; and the hinge
question was as important in moUuscan as in lampshell life.
Many forms were doubtless still living in old-fashioned shells
without hinges ; and in the case of some others the hinge was
only imperfectly developed. But a few forms — forerunners
of which had appeared in the Cambrian — had shell-hinges
which were of superior mechanism to those of the most
progressive lampshells (Ctenodonta). Such animals, therefore,
were well equipped against burglarious starfishes, and other
shell-intruders in the shallows.
UNIVALVED Winged snails had less weight to carry than of old, for

MOLLUSCS their shells were now of much thinner texture (Cornularia).

New species of crawling snails were also in the seas ; but
there is no reason to suppose that they had undergone any
very important modifications of internal anatomy. Some
of them now possessed on the upper part of the foot a hard
growth (operculum), which served as a trap-door to the shell
as the animal lay coiled up within (Maclurea). Hospitality
was more rigorously denied. The more expansive forms with
well-raised towers to their shells (Cydonema) were notably
on the increase. Others (Helicotoma), to judge by their shells,
had had their flanks considerably flattened, and had probably
become more athletic.
SCAPHOPODS Scaphopods or " tooth-shells " were in existence at this
time (Dentalium) — spending their lives more or less embedded
in the mud and sand. They added nothing, therefore, to the
gaiety — little enough — of marine life.
CHITONS Other animals — equally stolid — were ancestors of the
" armour-shells " or chitons of our own time ; and, save for
their shell-plates not being so firmly secured to the margin
of the mantle, they seem to have differed but little from the
forms now living {Priscochiton).

ORDOVICIAN PERIOD

Some very small animals, distantly related to lampshells — P0LY20ANS
and more highly connected, therefore, than the coral-related
graptolites — were now in evidence. Whether any of them
lived in solitary state is unknown, but many colonies were
certainly in existence. Some of these extended themselves
over stones, shells, and other marine objects ; others had
taken root, and branched out in plant-like form, and resembled
the " seat-mats " and so-called " lace-coral " of our own
time. They certainly had a longer future before them than
Graptolites, for there is no doubt that the polyzoans of to-day
are their descendants, whilst Graptolite annals soon came to a
close. Polyzoans differed in character, for in some colonies
the zooids lived in round-mouthed and well-opened tubes
(Cyclostomata) ; whilst in other colonies — probably an off-
shoot— the tube orifice was more or less protected {Crypto-
stomata). There were, therefore, two developments competing
for Natural Selection ; and what the result would be, time
alone could show.

Descendants of the Cambrian nautiloids in straight and cephalopods
slightly curved shells were numerous in Ordovician times.
In North American waters some forms attained enormous
dimensions, possessing shells a foot in diameter in front, and
twelve feet in length (Endoceras). Such giants, suggestive in
appearance of drifted tree-trunks, doubtless took terrible
toll of various forms of marine life. Owing to their ponderous
encasements they probably remained more or less stationary,
throwing out their tentacles when prey came within reach.
It is clear, however, that in this Period modifications were in
progress towards rendering the shells of nautiloids more
portable. Some forms were now appearing in shells partly
coiled in the uninhabited portions ; and the whole structure
thus assumed the outline of a pastoral staff (LiUiites). The
shells of a few others were more or less completely coiled ;
and had, therefore, an outward resemblance to the shell of the
existing Nautilus (Trocholiies). These modifications were
destined to revolutionise this class of life ; but as yet an
immense majority of the animals lived in shells of old fashion.

Trilobites were making great progress ; and, during this TRILOBITES
Period, attained their climax. Some Cambrian genera had

EVOLUTION IN THE PAST

passed away ; but many new genera had appeared. The new
forms, with few exceptions, were endowed with eyesight, and
were more broadly developed in the region of the tail {Asaphus^
Trinucleus, Ceraurus, etc.). The power to roU up in wood-
lice fashion was also more common (Calymmene) ; but this
mode of meeting dangers was not suggestive of a grand
future.

POD-SHRIMPS Numerous " pod-shrimps " were disporting in the waters,
and of larger size than their Cambrian ancestors (Ceratio-
caris).

OSTRACODS Ostracods, some dwelling in rock-pools, others careering
in large companies about the deep, were in a vigorous con-
dition. In fact, their shells were never so varied at any other
time (Beyrichia, Bairdia, etc.). They were mostly minute
animals, but some monsters — nearly an inch in length — were
among them {Leperditiidce). In some cases — ^in the style of
lampshells and bivalved molluscs — hinges were developed
on the tiny shell ; and in some shells there was a small
perforation through which the antennas could be thrust
without disturbing the valves (Cypridma).

BARNACLES Attached to rocks, shells, and seaweeds, barnacles ex-
hibited their peculiar structure in various stages of develop-
ment. These animals had early departed from strict crusta-
ceans, and were fast becoming an isolated group, leading
lives similar to those of rock-clinging molluscs. Some were
protected by loosely-arranged shelly plates (Lepidocoleus) ;
whilst others were more or less completely encased in plates
closely set and overlapping (Turrilepas). None of these
barnacles possessed stalks for chnging to their resting-places.
They may, indeed, have been capable of locomotion, but
probably they did not much indulge in this exercise. Others
had stalks of a rude, primitive kind (Polliceps) ; and in a few
forms this organ was well developed {Scalp ellum).

SEA- There is no sign of small crustaceans with affinities to

SCORPIONS trilobites and king-crabs, such as had appeared in the Cam-
brian. But the smaU scorpion-like animals (Eurypterids)
were on the increase (Echinognathus, etc.). Sea-scorpions,
so-called, did not, however, make their presence greatly felt
in Ordovician times. Their descendants, as wiU be seen.

ORDOVICIAN PERIOD

became important animals not only in the sea, but in fresh
water also.

Marine life, it will be noted, was for the most part strong
in defence ; and various animals of active and aggressive
habits — of which nothing is known — may well have been in
the seas. Fish-like forms were possibly coming to the fore,
but there is no satisfactory evidence as to this. If — as is
likely — they were already in existence, they were probably
backboneless and soft-bodied, and had, therefore, no enduring
" wrack " to leave behind.

On land, primitive " horsetails " (Protannularid) and club- vegetation
mosses (Proiostigma) were extending their range. Other
verdant forms bearing mostly wedge-shaped leaves seem
to have been combinations of these, and to have held, more-
over, affinities with ferns (Sphenophyllum). Insects were insects
certainly about the scenes (Protocimex). These creatures
were well-winged, and appear to have been a species of the
bug order (Hemiptera). Their presence leads one to suppose
that various insects of lower grade, especially wingless forms,
were already in existence. Many of them by this time may
have quite forsaken the waters, where their ancestors —
probably minute crustaceans — had long dwelt and prospered.

PALEOZOIC AGE

SILURIAN PERIOD

VEGETATION SiLURiAN life attested a well-sustained progress. Vegetation
was becoming more diversified; dub-mosses had greatly
increased in variety {Berwynia, Sagenaria) : and some plants
had now become so far evolved as to be distinguishable as
ferns (Sphenopteridium). All Silurian plants, it would seem,
reproduced by means of spores — a somewhat circuitous and
extravagant process for the end in view. The seed-bearers —
more straightforward and less prodigal in posterity matters —
were yet to come.

SPONGES The advance in marine life was necessarily attended by
the falling out of many old forms and types. Increased com-
petition, and other changes in environment, though con-
ducive to progress, were bound to bring sectional reverses.

Sponges with simple rod-like needles — so prevalent at the
present time — are first known in Silurian seas (Monaxida).
The flinty supports may in some cases have been worked
up into a framework, but probably they were more often
scattered about the porous " flesh." A rigid framework must
have interfered with a free development of canals ; and the
sponges that eschewed it developed, no doubt, highly im-
proved canal systems, and so became enabled to confront
more varied conditions. Some forms, in course of time,
entirely discarded needles. This was a hazardous proceeding,
for many animals — no longer afraid of a prickly reception —
took to preying on them. In long after-times this innocuous
condition also led to their use as bath-sponges.
CORALS Solitary corals in thick-walled cups were numerous (Zaph-
rentis, etc.) ; but what may be called reef-building was now in
evidence. Certain forms, presenting in the mass a honey-

SILURIAN PERIOD

comb appearance, were conspicuous in this activity (Favo-
sites). The body-cups, although of thick texture, were per-
forated ; and a community of Hfe was, therefore, to a certain
extent estabUshed. Other colonies, presenting a chain-like
appearance, were also much to the fore (Halysites) ; but
individualism on these reefs was more or less rigidly main-
tained. The two schools of compound corals — communicative
and close-walled — were, therefore, represented.

Graptolites were now on the wane. The more populous graptolites
double-rowed colonies seem to have died out in the early part
of the Period. The colonies with single rows of individuals
continued somewhat longer. But though their wants were
fewer, they were having a hard struggle for existence ; and
by the close of the Period they became practically extinct.

Changes had taken place in the ranks of the cystids. cystids
The progressive Ordovician families — characterised by a
more symmetrical arrangement of the box-plates, and by the
development of " arms " — were still in existence : and the
families which had shown progress only by developing
"arms" were still living, but in diminished numbers. The
more primitive Cambrian family, without " arms," and with
irregularly arranged plates, had apparently died out (Aristo-
cystidcB). Stems were but little, if at all, developed by early
cystids, but in the Silurian Period some well-stemmed forms
were to be seen. These more dignified creatures had also other
advantages. Their facilities for collecting food were increased
— as in the case of some crinoids — by the development of
feathery appendages on the somewhat diminutive arms :
and they also possessed improved channels for conveying
food to the mouth {Lepadocrinus).

Cystids seem to have been fairly prosperous during the
Silurian ; but there were signs of decline. They were, in fact,
slowly failing in their competition with crinoids or " sea-
lilies," and had, indeed, by this time, been far surpassed by
the latter alike in number and variety.

Crinoids were spreading in the seas with all the luxuriance sea-lilies
of tropical jungles ; and many large-cupped, graceful forms
were now to be seen (Periechocrinus). Those with mouths
rendered more free for the reception of food by the removal

EVOLUTION IN THE PAST

of the covering disc were in a small minority in the previous
Period (Ichthyocrinidce). During the Silurian such forms were
more in evidence. Among crinoids with covered mouths
some highly speculative developments for dealing with the
force of currents were taking place. In certain forms the
arms were joined together by means of numerous branches
resulting in a sort of network enclosure (Crotalocrinus). In
a few other forms each branching arm was compacted
into a fan-shaped petal (Petalocrinus). These experiments
were not very successful, for wicker-crowned and petalled
crinoids did not appear in any subsequent Period. Other
forms had come out as sanitary reformers. The sanitary
arrangements of many crinoids were doubtless far from
perfect, as the waste products in passing away were liable to
mix with the food supplies. To ensure against this, some
forms had evolved long tubes calculated to carry the waste
clear of the arms (Mastigocrmus, Botryocrinus).

Various modifications had been undergone in other cases,
resulting in a freer play of the " arms," greater flexibility
of the stem, increased strength of the cup or body-covering,
and the out-growth of small clinging tentacles as means of
support. Indeed, crinoids seem to have attained their
greatest development in this Period ; but they all differed as
yet, in several structural details, from crinoids now living.

BLASTOIDS Some related animals known as Blastoids were now on
the scene. So far as is known they were confined at this
time to North American waters. The most remarkable feature
about these " bud-like " creatures was the presence beneath
the body-covering of certain tubes, known as hydrospires.
Currents of water, it is supposed, passed through the tubes,
and respiration was thereby carried on. This was, un-
doubtedly, a less simple respiratory system than that of
breathing by pores, as was the general rule with crinoids ;
and it may have yielded a greater thrill of life. Some of the
animals (Troostocrinus) had the system more fully developed
than others (Codaster). And various experiments were, no
doubt, being made, for the creatures were as yet but tyros
in the maze of competitive life.

STARFISHES Old-fashioned Cambrian forms of starfishes with ill-defined

SILURIAN PERIOD

central discs were still in being. Certain forms were now
more in line with those of to-day in having a thorough
protection for their tube-feet {Lepidaster). Some of the brittle-
brittle-stars had undergone a similar modification {Lapwor- stars
thura). The latter animals were now well distinct from
the starfishes ; and by coiling round crinoids and other
acrobatic feats they doubtless displayed their superior
agility.

Various forms of sea-urchins were groping about amongst sea-urchins
the seaweeds, or lurking in rock-hollows. They all differed
from the known Ordovician forms (which had become
extinct) in having tests with more numerous vertical plate-
rows. In fact the plate-rows were more numerous than those
on the body-coverings of any urchins now living. The tests
of some were of a quite primitive character, the plates being
thin and irregularly arranged (Echinocystis). In a few cases
the under-part of the test was not perforated, and the lower
tube- feet had to be protruded between the plates (Palceo-
discus). The tests, no doubt, were highly flexible ; and a
very slight misfortune would have cracked them across
had they been otherwise. Urchins thus encased, however,
were not the best clad of the time ; for certain forms were
abroad in tests of stout, rigidly attached, and well-perforated
plates (Palceechimis). These animals were about the size of
greengages, and were more or less covered with short bristles.
They possessed, moreover — unlike their humble brethren — a
well-developed jaw apparatus, capable of gnawing into the
shells of molluscs. They were certainly the " fittest " urchins
in the seas, and proved fit enough, indeed, to continue their
line through the next two Periods.

The Ordovician worms, that had betaken themselves to worms
extremely sedentary habits in chalky tubes cemented to rocks,
had by no means entered on a fatal course. In spite of aggres-
sive sea-urchins, and other intruders on their privacy,
numerous descendants were living in this Period. Indeed, the
line has been perpetuated until the present time (Serpulites).

Brachiopods or lampshells were in a state of vigour they lampshells
had never experienced before, and were never to know
again. Not only on the coasts of Europe, Asia, and North and

EVOLUTION IN THE PAST

South America, but on Australian scenes they made a grand
display. The shells were wonderfully varied in shape, pattern,
and structural detail ; and there were differences also in the
texture and the material of their composition.

The species with hinged shells had now far outstripped the
" unhinged " {Pentamerus). Forms were arising that had
developed spines on the shell — a new means of clinging to
resting-places (Chonetes). The " arms " of some had now
become so greatly developed that the shells in order to lodge
them had assumed the shape of a butterfly with outstretched
wings {Spirifer). And there were many other displays of
originality in this plastic group. The animals, in short, were
at the height of their glory : but a great sifting-out process
was not far distant.

POLYZOANS Whilst the graptolite colonies were declining, conditions
seem also to have been unfavourable to the colonies of
higher grade, known as polyzoans. The older-fashioned
open-mouthed colonies still kept the lead, but they had now
lost their great superiority in numbers over the colonies
with zooid-tubes of greater complexity.

BIVALVED Bivalved moUuscan life still remained in a primitive ill-
MOLLUSCS defined condition ; but there were signs of progress. Some
animals were appearing in a state of development between
mussels and pearl-oysters (Myalina). Other forms were more
in line with modern wing-shells than were their Ordovician
forerunners (JPteria). A few new forms were appearing in
exceptionally pretty shells, shaped like a cockle's, and
with radiating ribs broken up into small knobs by cross
furrows (Cardiola). These creatures seem to have been more
nearly related to arks than to cockles : but their family was
not destined to a very long career. With better prospects
were certain other new forms, in shells of scallop pattern
{Aviculopecteii).

UNIVALVED Sea-snails did not exhibit much notable development.
MOLLUSCS Members of some families persisting from the Cambrian had
their sanitary arrangements in an improved condition. The
waste substance had been promiscuously discharged, and must
often have polluted the water coming to the gills. It was
now carried through a deep notch or sUt in the shell, and

SILURIAN PERIOD

kept clear of the breathing water (Pleurotomariidce, Bellero-
phontidcB).

The only new forms of importance possessed long turreted
shells with well-defined spires (Macrochilma, Loxonema).
The MelaniidcB of our own day may be descendants of these
sea-snails. If such be the case the family, in course of time,
must have migrated from the sea ; for its members now
live in fresh water only.

Scaphopods or " tooth-shells " had undergone some slight scaphopods
structural changes. They were, however, wellnigh sufficiently
modified for perpetuation through the ages ; for present-
day scaphopods differ but little from them (Dentalium).
In spite of excessively sluggish habits they have managed —
unlike some molluscs — to retain their heads. Hearts never
seem to have been a scaphopod property.

Nautiloids in more or less straight shells were still abundant, cephalopods
There were also new species of these old-fashioned forms ; the
shells having undergone modifications in the chamber-
partitions, or in the position of the tube which connected
up the various chambers. Huge animals with excessively
ponderous shells, such as had appeared in Ordovician times,
had apparently died out. Life no doubt had proved unequal
to the burdens which gluttony had entailed. Straight-
shelled nautiloids of considerable size were, however, still
conspicuous in marine life (Orthoceras annulatum, etc.).

Some peculiar forms were now appearing boxed up in egg-
like shells with a T-shaped aperture. Through this contracted
opening the " arms," no doubt, could be thrust ; but the rest
of the animal must have been held close prisoner (Gom-
phoceras). This seclusion doubtless had a protective value ;
but in the end the drawbacks proved greater than the ad-
vantages. Nautiloids, however, thus sequestered, were in
evidence during the two succeeding Periods.

The forms with coiled shells were making a decided advance
in numbers. Those in shells of the transitional pastoral-staff
pattern were certainly on the wane : but there were many
new species in shells more or less of nautilus-shape (Herco-
ceras, Trochoceras, Ptenoceras). The coiled -shell forms
were destined in time to supplant those in shells of older

EVOLUTION IN THE PAST

fashion ; and the latter seem already to have been on the
decline.

TRILOBITES Trilobites continued in considerable force, and were widely
distributed. The blind forms were still languishing, and
reverses had been sustained by several old families gifted
with eyesight. In some genera important changes were
taking place in regard to the eyes. In certain cases these
organs had been shifted to new positions ; and some forms
bore their eyes elevated on stalks. There was apparently more
need for vigilance than in times of yore.

Many of the trilobites had undergone variations in the shape
of their head and tail armour {Phacops, Sphcerexochus, etc.) ;
and the power to roll up in wood-louse fashion was still more
in evidence. Many of the modifications seem to have been
the result of a mere exuberance of energy : at any rate their
precise use and value cannot be determined. Fantastic forms
were now to be seen. Some of these had swollen unchecked
heads, covered with pimple-like excrescences (Staurocephalus).
In some species the cheek armour had been modified into
spines, suggestive of rigid fins ; and the tail armour had
followed suit (Deiphon). Several forms were appearing with
long spiky tails, enabling an animal thrown on its back to
rectify its position {Dalmanites limulurus, etc.). Trilobites,
however, though still able to adapt and re-adapt themselves
to the pressure of conditions, were coming to the end of their
resources ; and during this Period their decline commenced.
KING-CRABS Several species of small animals with head-shields and
spike-like tails, and holding affinities with trilobites and
king-crabs were now on the scene. Animals with these
double affinities had appeared as early as the Cambrian
Period (Aglaspis). The Silurian forms were certainly more in
line with king-crabs. They retained, however, a marked
trilobite character, as the segments of the middle body or
thorax were not fused together : the second shield of the
king-crab was, therefore, undeveloped (Hemiaspis limuloides,
Woodw., Neolimulus falcatus, Woodw.). King-crabs, in
short, were as yet but half made.
SEA- Sea-scorpions — of small account in Ordovician times —

SCORPIONS were now giving promise of their coming importance. As

SILURIAN MARINE LIFE

Lepidaster
[To face page 34

SILURIAN PERIOD

regards habits they had parted company ; one section con-
sisting of more or less active swimmers ; the other of forms,
capable indeed of swimming, but more or less addicted to
prowling about the sea-floor. To judge from their greater
size, and variety, the active swimmers were the more prosper-
ous. The last pair of limbs or appendages, in their case, had
been modified into powerful paddles, and the tail was some-
what short, and in some instances plate-like (Eurypterus,
Pterygotus). In the prowling forms the hind-limbs were
greatly elongated and single-clawed, and the tail was long
and slender (Stylonurus). Sea-scorpions brought forth
monsters in later times ; but the largest known Silurian form
scarcely attained two feet in length.

Animals intimately connected with sea-scorpions, and SCORPIONS
probably an off-shoot of them, were now coming into view
{PalcBophonus). These creatures seem to have closely re-
sembled the scorpions of our own time ; excepting that the
limbs terminated not with double but single claws. They
certainly possessed venomous stings ; but it is doubtful if
they resembled living scorpions in being land-dwellers.
They may well, however, have paid occasional visits to the
leafy scenes, where an increasing insect-population must have
presented an attraction.

Ostracods seem to have had a set-back after their great ostracods
burst of prosperity in the previous Period. Small crustacean
life, however, was now being enriched by the appearance of
amphipods, popularly known as " beach fleas " and " sand- amphipods
hoppers " {N ecrogammarus).

Through the greater part of the Silurian there is no satis-
factory evidence of any animals other than invertebrates ;
but towards the close of the Period there is little doubt that
animals with at least rudimentary backbones had emerged
from invertebrate ranks.

The great majority of these representatives of higher ostraco-
life, although fish-like in appearance, were much of the grade derms
of hags and lampreys — animals not regarded as true fishes.
Some, measuring about seven inches in length, had flattened
heads, big in comparison with the body, and were somewhat
skate-like in shape. Their skins, like the skins of sharks,

EVOLUTION IN THE PAST

were covered with little tubercles or prickles of a dentine
substance. There was a fin on the back, and a forked tail fin,
but apparently there were no paired fins as in the case of all
true fishes (Thelodus). In some species the skin-prickles stood
out like little spines (Lanarkia).

Other forms, similarly finned, were spindle-shaped like
most living fishes. The tubercles on the body had been fused
into well-defined scales ; but those of the head had not under-
gone the process. These creatures, unlike the flat-headed
forms, possessed on the under-part of the bod\^ a row of
spiny scutes (Birkenia). Other allied forms had a few rod-like
structures at the back of the head, and were liberally supplied
with scutes along the ventral region ; but they do not appear
to have had the other parts of the body protected (Lasanius).

Yet other odd-looking little forms had the head and the
anterior part of the body encased in shields consisting of small
shelly plates. The rest of the body — to judge from more
complete remains found in the next Period — was protected by
enamelled or ganoid scales (Cyathaspis, Palceaspis, Pteraspis).
A few forms were shielded in the region of the head only.
But this armour, less in quantity, was of better quality, for it
contained a certain amount of bony material (Tremataspis,
Cephalaspis). The appearance of bone is notable : for bone-
making cells were rare in those days. " Backbones " at best
were as yet only of a gristly, cartilaginous substance.

These various fish-like forms — known as Ostracoderms —
were probably of somewhat inactive habits, and seldom rose
much above the sea-floor. They did not, therefore, greatly
disturb the prevailing quiescence.

True fishes were also in Silurian seas. Certain small fin-
spines have been discovered, resembling in character the
spines that protect the dorsal fins of Port Jackson sharks
(Onchus). If these creatures fed on molluscs, their tables were
amply spread. There is also evidence of small sharks of
another kind (Climatius) ; and small sharks, there is little
doubt, were the first true fishes that ever swam the seas.
These small Silurian forms may have been derived from
creatures much of the type of the prickly-skinned, unshielded
ostracoderms (Thelodus). The shielded ostracoderms held

Lasanius

Lanarkia

Birkenia

Thelodus

Lasanius

Cyathaspis

Tremat-
aspis

Nautiloid
(Gompho-
ceras)

Lampshell
(Spirifer)

Hemiaspis

Chonetes

Sea-urchin
( Palaeechi-
ims)

Staurocephalus
SILURIAN i^MARINE LIFE

Deiphon
[To face page 36

SILURIAN PERIOD

strong affinities with trilobites and half-made king-crabs ;
and it is not Hkely that any of their descendants ever figured
as true fishes.

The appearance of fishes attested the rise of a new power
in the sea ; and, as after-events proved, it was not to be a
marine power only, but had wonderful destinies beyond its
native element.

Long had the waters embraced sponges, corals, sea-liUes,
molluscs, and creatures in crusty armour variously wrought ;
and now they nursed a life higher and more resourceful
than any of these. Different indeed was the land with its
humble verdant growths, and populated by animals of no
higher grade than insects.

PALEOZOIC AGE

DEVONIAN PERIOD

Fish- LIFE now abounded not only with strange types, old and
new, but also with a variety of species less quaint and prob-
lematical.

OSTRACO- Sluggish flat-headed creatures in skins dotted with dentine
DERMS were here much as those of the Silurian (Thelodus) ; and new
and apparently related forms were also in being. In the case
of the latter the scattered dentine had been collected and fused
into plates and scales ; and a protection resembling cuirass
and chain armour had resulted (DrepanaspidcB).

Shielded forms of the same character as those of the
previous Period were now in great force ; and, as a rule, of
larger size. Those, for instance, with bony head-shields
attained in some cases a length of two feet ; — ^twice the length
of the finest of their Silurian ancestors (Cephalaspidce).

There were also some forms — rarely more than a few inches
long — with only remote likeness to Silurian types (Pterichthys,
etc.). They were fully armed with bony plates and scales ;
and the eyes were well brought forward as on a human face.
The mouth appears to have been of a primitive kind, without
bony jaws. The most remarkable feature of these little
curiosities was the possession of jointed breast fins or paddles.
These plated appendages were probably used for crawhng
as well as for swimming and balancing purposes.

None of these shielded fish-like organisms — whatever may
have been the possibilities of unknown earlier and less
specialised forms — represented a progressive movement. In-
deed their total disappearance was not far distant ; for at
the close of the Period they all became extinct.

Some small vertebrates, long-tailed, and with large mouths

Proetus Puphricaris
DEVONIAN PERIOD [To face page 38

DEVONIAN PERIOD

bristling with tentacles, were also swimming about. These CYCLOSTO-
creatures were not true fishes ; for they had no paired fins ; mata
nor were their mouths surrounded with any hard material
constituting jaws. The largest of them, so far as is known,
did not exceed two inches in length : and their bodies seem
to have been unprotected by any plates or scales (Palceo-
s-pondylus). In anatomical respects they resembled lampreys ;
but they were more highly developed than those animals.
Possibly they represented that line of life before it entered on
a path of degeneracy.

Other and much larger forms were partially armoured, arthro-
and were provided with toothed jaws, and also, at least on dirans
the hinder part of the body, with paired fins (Coccosteus).
These true fishes were peculiar in being able to raise and
depress the head without moving the body — hence their
name the " joint-necked " (Arthrodirans). The nature of
their teeth suggests a relationship with lung-fishes. They
had, however, become too far specialised to be of any service
in the work of Evolution. They represented, in short, an
unsuccessful divergence, as did the armoured semi-fishes ;
and they experienced a like fate at the close of the Period,
or soon after. In North America some of the later forms
measured fully twenty feet in length (Dinidhys Herzeri).
These nodding giants were quite without teeth, and the jaws
had been transformed into a sort of nipper and nutcracker
apparatus.

These various vertebrates, therefore, were, so to speak,
in the shade. Indeed, the lamprey-like organism was the only
bright spot among them. But fish-life, though destined to
come to naught in some of its developments, had made great
advances in other directions. This state of affairs is brought
out in bold relief in the geological record : but there is a
remarkable lack of evidence as to the intervening stages of
the progress.

Shark-like fishes, in some evidence in Silurian times, were SHARKS
now represented by several species. The biggest forms
varied in length from two to five feet (Cladoselache). As
regards skull and jaws they resembled the cow-sharks (Noti-
danidcB) of our own time, but in other respects they were

EVOLUTION IN THE PAST

of primitive character. The " backbone " — composed of
cartilage — was unjointed ; but, not being stoutly developed,
it retained a fair amount of flexibility. The paired fins seem
to have been capable only of an up-and-down flapping move-
ment ; and these, though useful as balancers, can have been
but of little service for guiding purposes, or for assisting in
onward locomotion. Their character gives support to the
theory that fins originated as mere folds of flesh, strengthened
by outgrowths from the internal skeleton ; and that in time
the folds became divided up into distinct flippers, which
gradually developed increased functional powers. The tail,
however, is the great organ of propulsion ; and these fishes
were not devoid of strength in that quarter.

More advanced in development were certain small sharks,
forerunners of which had appeared in the Silurian (Climatius,
Mesacanthus). The fins of these fishes, both vertical and
paired, were well developed ; and, excepting the tail-fin,
were fore-guarded by spines. Some of these little creatures
were as much as a foot in length, and no doubt were the
elite of shark-life at this time.
CHIMJERAS Other shark-like forms, to judge by their teeth, were
developing in the direction of chimaeras (Ptydodus). But
the goal to which they were tending was as yet a long way off.
GANOIDS Other fishes of more engaging aspect were moving about
in bony scales enamelled with a glistening substance (ganoin).
This shining habiliment was doubtless the result of modifica-
tions of small tooth-like plates such as were formed in the
skin of early shark-like forms : but how the transformation
was effected is quite unknown.
CROSSOP- Most of the ganoids — as these fishes are called — possessed

TERYGIANS somewhat stiff, paddle-like fins ; and as the appendages were
bordered with thread-like structures, their owners are known
as " fringe-finned " ganoids (Crossopterygii). The median
fins — useful in keeping a fish straight on its course — had not
supports equal to the number of the rays, as is the case with
modern fishes. And the tail was not of the type best adapted
for swift straight-ahead swimming. All these features
tend to show that these ganoids cannot have been accom-
plished swimmers, at least according to modern ideas.

DEVONIAN SHARKS AND GANOIDS

[To face page 40

DEVONIAN PERIOD

Probably their habits were not much more active than those
of their contemporaries, the Ostracoderms ; and their time
was spent more or less in proximity to the shore (Osteleopis,
etc.).

Some of these ganoids possessed teeth of a complicated
pattern, brought about by an infolding of the surface enamel
(Tristichopterus). In certain forms this infolding was of an
extremely intricate nature (Holoptychius) ; and the teeth
resembled those of certain amphibians of later times. Notable
also is the fact that fishes with true backbones were at least
in promise ; the gristly spinal column in some cases having
undergone a certain amount of ossification (Tristichopterus).

Other ganoids, known as the " ray-finned " (Actinopterygii) actinop-
were better equipped for swimming purposes, as the paired terygians
fins were light and flexible. Their tails, however, were of the
same character as those of their fringe-finned relations, nor
were the median fins more efiiciently supported. No ossifica-
tion was as yet perceptible in the spinal column ; and there
was nothing remarkable in the structure of the teeth. These
undoubtedly more active fishes were apparently at the
commencement of their career ; and they were the " coming "
fishes. As yet they were few in number compared with the
fringe-finned ganoids ; and of no variety (Cheirolepis).

Other fishes, probably derived from the " fringe-finned " dipnoans
ganoids, seem to have been forerunners of the lung-fishes or
double-breathers of our own time (Dipnoans). Many of them,
no doubt, were denizens of the sea ; but some certainly
haunted lakes and rivers. The latter forms, indeed, may
have been true double-breathers ; i.e. with the air-bladder so
modified as to serve as a breathing apparatus supplementary
to the gills. A modification of this kind may have been
rendered necessary by the animals being left high and dry at
certain seasons of the 3'ear (Phaneropleuron, Dipterus).

No Devonian fishes had tails of the type that now prevails.
In the vast majority of living fishes the tail-fin radiates
from the stump-end of the spinal column. The fin, therefore,
is in a sense free of the backbone (homocercal tail). In the
■case of all Devonian fishes the spinal column extended to the
extremity of the animal, and its tapered end was bordered

EVOLUTION IN THE PAST

on either side with fin rays. In some cases the spine was
continued to its end in a straight Hne, as with lampreys
(diphycercal tail) ; in other cases the end was bent upwards
as in the case of sharks and sturgeons (heterocercal tail).
Lampreys, sharks, and sturgeons, therefore, are of antique
fashion as regards the tail, — to say nothing of other features.

In the Devonian Period, fish-life, it will be admitted, was
fairly launched on several lines of evolution : and it must
have been a great factor in the balance of power in the seas.
SEA- Among invertebrates, sea-scorpions were widely distributed.

SCORPIONS To judge by some greatly lengthened and enlarged forms,
they were exceedingly prosperous in certain districts. How
far they were indebted to fish diet for their robust develop-
ment is not clear. Some of the monsters, belonging to the
better swimmers of the fraternity, measured nearly six feet
in length (Pterygotus anglicus). The less active swimmers,
with fewer facilities, it may be supposed, for self-aggrandise-
ment, continued of more or less modest proportions.
TRILOBITES The decline of trilobites, which had set in during the pre-
ceding Period, continued, and in most regions with some
rapidity. Old families were dying out, or becoming seriously
impoverished ; and no new families were arising to fill the
vacancies. Desperate efforts were being made in some
quarters to keep pace with the times ; and the body armour
was assuming florid and fantastic characters (Terataspis
grandis, etc.). But it was all to no purpose. There was no
true energy behind it : and one is reminded of the wildness of
Gothic architecture as it passed to its decline. The soundest
family on the scene appears to have been one dating from the
Ordovician Period, consisting of small creatures with well-
developed heads, and clad in armour of simple character
(Proetus). This family was as yet far from extinction.
SHRIMP-LIKE Pod-shrimps — at no time chosen vessels for the evolution
FORMS of crustaceans of higher type — were now declining. Some
oddities, more or less closely related to them, were here and
there exhibiting themselves in round shields edged with spikes
(Pephricaris horripilata). Notwithstanding their horrific
aspect, they seem, one and all, to have disappeared after a
brief career. Far more important were other small forms

DEVONIAN PERIOD

{PalcBopalcemon), — forerunners, probably, of great develop-
ments in crustacean life.

Devonian ostracods have left no record of much importance, ostracods
The little creatures, with notches in their shells, through
which they could thrust their antennae, were certainly
prosperous (Entomis, etc.). Less fortunate were those
that could only protrude the appendages by gaping the shell-
valves.

A few isopods are first met with in this Period. This not isopods
very respectable group of crustaceans comprises sea-slaters,
louse-crabs, gribbles, woodlice, and pill-bugs. In Devonian
times, however, these isopod potentialities were concentrated
within the narrow bounds of a few indefinite creatures
(Prcearchirus, Amphipeltis).

MoUuscan life was becoming more prominent than of old.
Its numerous species for the most part greatly differed from
modern molluscs, but there were some clear signs of modifica-
tions in the direction of existing forms.

Among cephalopods there is no evidence, it is true, of
cuttle-fishes and squids which now represent so largely
this leading class of molluscs ; but great movements were in
progress.

The Nautiloids apparently were not so flourishing as in
former times. Old-fashioned forms with more or less straight
shells had become impoverished by the loss of some genera ;
and seem now to have been surpassed in numbers by those in
coiled shells of the nautilus type.

The most notable cephalopods of the time were certain ammonoids
molluscs, closely alHed to the nautilus-like creatures, and
known as Ammonoids. Their shells, as a rule, somewhat
resembled a ram's horn in shape ; and the Order for that
reason has been named after the Egyptian god Ammon,
generally represented as a man with a ram's head.

Some of the ammonoids of this Period had shells much of
the shape of those of the straight-shelled nautiloids (Bactrites).
The ram's horn name, therefore, is not strictly applicable
in their case ; but as in certain internal features of the shell
they differed from nautiloids, and resembled typical am-
monoids, they are classed with the latter. They were probably

EVOLUTION IN THE PAST

survivals of some ancient forms, that had initiated the Am-
monoid Order.

All other ammonoids may be divided broadly into two
groups, — Goniatites and Ammonites. The Goniatites were
the earlier forms. Their shells were of no great variety, and
were generally of plain outward appearance. The partition-
patterns — not, as a rule, externally visible — were in most
cases of extremely simple character. The Ammonite patterns
attained a wonderful degree of complexity.

Many of the Devonian goniatites — ammonites had
not yet appeared — were probably active swimmers
(Gastrocampyli, Microcampyli). There is no doubt, however,
that crawling habits were in course of adoption. In some
forms (Clymenidce) the partition-patterns were characterised
by a slight elaboration. And this, no doubt, had resulted
from strains on the shell caused by crawling becoming more or
less habitual.

Goniatites became very numerous in the course of the
Period, and increased in genera (Gephyroceras, Tornoceras,
Anarcestes, etc.) : but their shells continued of plain outward
appearance, being either smooth on the surface, or marked
only with delicate streaks.
UNIVALVED Gastropods for the most part were of the same character
MOLLUSCS as those of the preceding Period. A few of these snail-forms,
however, had apparentl}^ developed a lung-chamber, and
become capable of breathing out of water (Hercynella). The
humble land-population was in prospect, therefore, of obtain-
ing more recruits.

BIVALVED Bivalved molluscs exhibited considerable development.
MOLLUSCS Primitive oyster forms, belonging to the family of which the
saddle-oysters of our own day are members, were now abroad
(Limanornia). Other forms appear to have been well on the
way to becoming horse-mussels (Modiola) ; and burrowers
of the " razor-shell " type were also on the scene (Palceosolen).
Some forms had moved up from salt to brackish and fresh
water. Certain of the emigrants bore a close resemblance
to river-mussels {Archanadon).
POLYZOANS Polyzoan colonies, though suffering vast losses owing
to the rapidly increasing molluscs, and, possibly, fishes,

DEVONIAN PERIOD

were now represented by various old and new forms. The
colonies with open-mouthed zooids still seemed to be keeping
ahead (Cyclostomata) ; and one family, which had first
appeared in the preceding Period, and was notable for the
large size of its zooids, became exceedingly prosperous
{FistuliporidcB). Among the " hidden-mouthed " — the later
developed colonies — several new families were becoming estab-
lished ; but an old family of Ordovician date, whose members
resembled the " lace coral " of our own times, was dominant
in this division (FenestellidcB).

Lampshells were now dechning ; but they were by no means lampshells
descending rapidly from their zenith. Those in old-fashioned
shells, without hinges, were certainly facing the turn of events
with ever-weakening forces ; and some old families had
become fossil. But some forms of later development in hinged
shells well maintained their position. Those, for instance,
in shells of butterfly outline, were now in great force, and
widely distributed (Spirifer). And the pressure of conditions
was elsewhere eliciting responses, resulting in important
modifications. Some brachiopods, for instance, now had their
" arms " gathered up within the shell in simple loops. This
new fashion, it may be supposed, brought some advantages
relating to breathing and feeding ; for its followers made
great progress, and atoned in part for reverses incurred by
brachiopods in other divisions of the Order (Terebratella).

Sea-urchins were no longer to be seen in such primitive sea-urchins
tests as protected many of the Silurian forms. All the animals
were now in fairly strong body-coverings, and possessed,
moreover, well-developed jaws. The descendants of the
rigidly encased Silurian animals probably held the lead
{Palceechinus). In other forms the tests were made up of
stout plates, but, as these overlapped, the old feature of
flexibility — no longer urgent — was still retained {Lepido-
centrus). All the tests still notably differed from those of
existing urchins, owing to an excessive number of vertical
plate-rows. Modifications, however, were in progress in the
direction of economy, and also of greater efficiency.

Brittle-stars were giving distinct signs of progress. In brittle-
addition to those with extremely flexible arms, some forms stars

EVOLUTION IN THE PAST

were now appearing with the arms strengthened on all sides
with small plates as is the rule with modern forms (Eiio-
phiurecs). This development, no doubt, deprived the hmbs
of some flexibility ; but it considerably improved the
ambulatory powers of the animals.
STARFISHES Starfishes of Cambrian form were still in the seas ; but
were now in a failing condition, and before the close of the
Period they became extinct (PalcBasterina). Other forms, of
later evolution, but with archaic features — notably in the
construction of the arm-grooves — continued in some force
{Palceaster). Several of the new Devonian forms seem to have
been closely related to starfishes of our own time ; but their
sensitive skins were probably not so well protected {Astro-
feden, Echinasterella).
BLASTOIDS Blastoids, confined, so far as is known, during the preceding
Period to the " new " world, had now discovered the " old,"
and were in some force in European waters. The pecuhar
breathing apparatus, for which these bud-like animals were
remarkable, had undergone some modifications (PentremitidcB,
Eleacrinus). The tubes or hydrospires had been brought into
closer co-operation, resulting, no doubt, in easier breathing
and a consequent saving of energy.
SEA-LILIES Crinoids or " sea-lilies " seem to have been scarcely so
prosperous as in the Silurian seas, but they still greatly out-
numbered all other members of the " spiny-skinned " fra-
ternity.

The sanitary reformers do not appear to have been making
great progress. But in some localities they were fairly
numerous ; and certain forms had the long tube on an
exaggerated scale (Eucalyptocrinus). The apparatus was
probably efficient in working, but it may have required more
protection against hostile attack than crinoids were able to
supply.

There is no doubt that in the Devonian Period crinoids
were being seriously affected by their foes ; among which
fishes, no doubt, were to be numbered. To meet dangers and
difficulties, a few forms were appearing in which the cup or
body-covering was protected by movable spines, resembling
those of sea-urchins (Arthrocantha). As this device never came

DEVONIAN PERIOD

much into vogue, either in this Period or afterwards, its
advantages must have been more apparent than real.

Cystids were fast dying out. However illustrious in the cystids
past as the stock from which " sea-lilies " and Mastoids had
come, their glory had now quite departed. They were
destined, however, to linger on for a time, but with an ever-
diminishing horizon.

On coral reefs the colonies of honey-comb appearance corals
(Favosites) were still conspicuous ; and new colonies — also
with zooids of the more social kind — were becoming impor-
tant as reef-builders (PhillipsastrcBo). The less social chain-
coral colonies, prominent on Silurian reefs, had now become
extinct (Haly sites).

Calcareous sponges, that is, sponges with needles or spicules sponges
formed of carbonate of lime, now come into view for the
first time. They continued very few in number during the
Period as compared with sponges with flinty skeletons, and
their needles were smaller and less varied than those of the
latter. Calcareous sponges never discarded needles, and con-
sequently have always enjoyed some immunity from sponge-
eating animals.

The land population was not of much higher character
than in Silurian times ; but there were some notable appear-
ances. Myriapods, with resemblance to certain millepedes myriapods
of our own day, and descended from annelid sea-worms,
were now abroad (Archidesmus, Kampecaris). Large-winged
insects, allied to may-flies, were flitting about (Lithentomum) ; insects
and rough music was to be heard ; for some of the number
had wings adapted for emitting a scraping noise (Xenoncura).

Doubtless there were many other forms of insects of
which no evidence has been discovered. For insect-life during
this Period must have been stimulated into a varied evolution
by the development of plant-life ; and may indeed have
rendered reciprocal services.

Vegetation retained many old features, but some important vegetation
developments were in evidence. Certain climbing growths
of ancient origin, and combining affinities with club-mosses,
" horsetails," and ferns, were prominent, but were not
developing sufficient stem-strength to stand alone {Spheno-

EVOLUTION IN THE PAST

phyllum). More stalwart were the growths of less wide
relationships, and represented by existing club-mosses. The
latter, possessing an outward appearance to mosses, are in
many cases not larger than those plants. Even in tropical
regions they are at best but shrubs and bushes. Very different
was the condition of their ancestors. As early as the Devonian
Period many growths of this type were big, branching trees,
towering far above most of the other vegetation {Lepidoden-
dron, Bothrodejtdron).

Occasionally rivalling them in height other forms with reed-
like stems, ringed at intervals with leaves (generally of
lanceolate shape), adorned the scenes (Calamodadus, Archceo-
calamites). These growths, known as calamites, attained
great importance, whilst the plant world still was young ; but
they have long since dwindled, and to-day are represented
only by the humble " horsetail " (Equisetum).
FERNS Ferns were increasing in variety ; and some forms (Astero-
chlcBna) apparently were forerunners of certain tropical
species of our own time {Marattiacece).
CYCAD-FERNS In addition to ferns and other spore-producing growths,
there were several fern-like plants which through frond-
modifications had passed or were in process of passing from
a spore-bearing to a seed-bearing stage (Alethopieris, Mega-
lopteris). As the growths were in a condition of development
between ferns and cycads, they are known as cycad-ferns
(Cycadofilices). Their appearance in plant-life was a notable
event, for it indicated a safer and more economical method
of reproduction than had hitherto prevailed. A spore is in an
ill-nourished condition when it leaves its parent, and, being
without an embryo, it cannot give rise forthwith to a plant
resembling the parent-form. Owing to their starved condi-
tion, and as the production of an embryo is a roundabout
and hazardous process, spores are produced in enormous
quantities. In the case of seed-bearers such profusion is
unnecessary, as the principle of parental care is much more
pronounced. Seeds are fertilised and well-nourished before
leaving the parent, and are in a condition to give rise forth-
with to growths resembling their parents. Fern-cycads,
therefore, testified to a safer and more economical method of

DEVONIAN PERIOD

reproduction ; and, moreover, their greater parental care
exhibited a notable development in plant ethics.

Before the close of the Period plants known as Cordaites cordaites
attested further progress in the evolution of seed-bearers.
These more advanced growths — of remote ferny origin —
exhibited strong affinities both with cycads and conifers,
and were of higher order than any other known plants that
adorned Devonian landscapes. No growths now exist that
bear much resemblance to them. Their slender stems —
composed largely of pith — rose in some cases several feet in
height. At the top — and there only — branches were thrown
out, bearing long and narrow leaves ; and here and there
amid the foliage small catkin inflorescences were in display.
These modest blooms, so far as is known, were the first
flowers that appeared in Nature.

PALEOZOIC AGE

CARBONIFEROUS PERIOD

The vegetation of the " Coal-bearing " Period was similar
in character to that of the Devonian, but it attained an
extraordinary luxuriance, and species multiplied greatly.
CLUB-MOSSES Branching club-mosses of pine-like appearance abounded ;

and in some cases rose to heights of one hundred feet and
more {Lepidodendron). Some small members of the varied
throng seem to have been of a present-day genus (Selaginel-
lites). Certain of these (Miadesma) and a few of the larger
growths (Lepidocarpon) had so far advanced beyond the
spore-producing stage as to bring forth what may be termed
SIGILLARIA seeds. Other club-mosses were spiky-leaved branchless
trees with stout trunks, scarred with seal-like impressions,
HORSETAILS left by shed foliage (Sigillarid). " Horsetails " with reedy
stems, bark-covered and fortified in part with well-developed
CORDAITES wood, Were now to be seen over sixty feet in height (Cala-
mites). Cordaites or cycad-conifers of many species were in
evidence ; and, so far as is known, continued the only
CYCAD-FERNS growths with any floral pretensions. Seed-bearing cycad-
ferns greatly extended their range, and new forms vied with
the old (Alethopteris, Lyginodendron, Lagenostoma, Aneimites).
Ferns of the same type as a now living group of tropical
FERNS ferns (Marattiacece) were in great abundance — some of
them attaining tree-like proportions (Psaroniiis) ; and old-
fashioned climbing growths of mixed affinities still kept a
place in the forests (Sphenophyllum).
COAL In swampy stretches of land, notably in England, France,
Germany, and in North America, this varied vegetation
underwent a series of remarkable vicissitudes. Trees, shrubs,

CARBONIFEROUS PERIOD

and smaller growths in their generations flourished and died ;
and from their accumulated remains, deep and extensive
peat-bogs were formed.

In course of time, owing to land oscillations, these peat-
bog areas — formed mainly in large deltas and estuaries —
gradually sank below the water-level, and became covered
with muddy deposits.

Coal was therefore in promise ; but the peaty material
had to be submitted to tremendous pressure from above, and
to undergo various chemical changes, before attaining that
condition. This was to be the work of Time.

As subsidence continued, an ever-increasing pressure
resulted from the accumulations of clay, sand, and other
earthy material deposited by rivers on the buried peat. In
some cases these muddy deposits were of enormous thickness,
indicating subsidence of very long duration.

After the downward movement had ceased, river-borne
deposits must have gone on accumulating, until they ap-
peared well above the surface of the waters. Whilst in some
regions the reappearance of land was doubtless accelerated
by earth movements resulting in actual upheavals.

Vegetation, no doubt, quickly spread over the new land :
and in course of time dense brakes and forests held the ground
beneath which the earlier sylvan wealth lay buried and
compressed.

Owing to a repetition of land oscillations the peat-bogs,
formed on these scenes of renewed verdure, experienced
in their turn the same fate as those of earlier formation.
The marshy areas sank below the water-level, and were
gradually overspread with mud and sand. Thus the material
for a second bed of coal, separated from the first by river-
borne deposits, and itself buried in like manner, became
stored in the strata.

In some regions these up-and-down movements continued
for an inconceivably long time, resulting in the entombment
of a series of peat-accumulations. The intervals in the
process, no doubt, varied greatly, for the layers of coal and
the intervening muddy deposits are of divers degrees of
thickness.

EVOLUTION IN THE PAST

Finally, it must be supposed, the waters in these great
peat regions acquired a lasting predominance ; and the
series of black seams in the strata was brought to an end.
INSECTS Carboniferous brakes and forests must have swarmed with
insects, winged and wingless. Primitive cockroaches {Pro-
gonohlattina, etc.), locusts, and grasshoppers appear to have
been especially numerous (Palceacrididce). May-flies flitted
about (Palingenia, Homaloneura) ; and forerunners of dragon-
flies were also on the wing (Protodonates). Some allied forms
were enormous creatures, with bodies a foot and a half in
length (Meganeura). Other of the insects apparently were
wingless, and were probably spring-tails of primitive de-
scription (Dasypeltus). Early forms of stick and leaf insects
were also in the woods {ProtophasmidcB) ; and some relations
of present-day snake-flies (Miamia). Most of the insects,
however, although comparable with living forms, were more
intermixed in their relationships than is the case in modern
insect-life. They were all probably either predaceous in
habit or suctorial, subsisting chiefly on juices of plants.
Environment was not yet favourable for the evolution of
flower-lovers and gatherers of honey.
MYRIAPODS Millepedes — first known in the Devonian — were now
SCORPIONS represented by many species. Certain scorpions by this
time had developed lungs, and taken to living more or less
SPIDERS on land {Eoscorpius). Various ancestral types of spiders were
now abroad (AnthracomartidcB). Some speciaHsed forms
(Geralinura, Eophrynus) resembled the predaceous scorpion-
spiders of our own time (Pedipalpi) ; and true spiders were
AIR- beginning to appear (Protolycosa, Palasajtea). Land life was

BREATHING also diversified by certain snails that had completely lost
GASTROPODS touch with their briny relations (Dendropupd).

Marine life was in a condition of vigorous development.
SPONGES Sponges with simple rod-like needles and improved canal-
systems became much more prominent (Monactinellids) : and
the older known forms, rigid with artistically arranged
needles, were flourishing in quiet waters (Tetractinellids,
Hexactinellids). Some new sponges now appeared with
needles more numerously rayed than any earlier forms. The
supports for the " fleshy " organism were irregularly dis-

CARBONIFEROUS PERIOD

tributed, and apparently did not greatly redound to the
welfare of their possessors (Hexactinellids) ; for sponges with
needles so elaborately developed had no representatives in
any later Period.

" Honey-comb " corals of the kind that built up Silurian CORALS
and Devonian reefs were now declining (Favosites), but some
closely allied forms {Michelinia) were in great force in some
regions — notably in a sea that then extended over Belgium.
New colonies were also appearing with zooids enclosed in
porous body-walls ; and by means of connecting-tubes a
greater community of life was established than what had
hitherto obtained (JPalcBacis). These more communicative
corals were possibly ancestral forms of one of the great reef-
building families of the present time (PoriUdce).

Cystids, long on the wane, were now on the verge of cystids
extinction.

Although abundant and diversified in some North American sea-lilies
waters crinoids appear on the whole to have been still
declining. The sanitary reformers, it is true, continued well re-
presented (A ctinocrinus, Platycvinus, Batocrinus) ; but the elon-
gated waste-tube was by no means becoming general. Many
crinoids, without any notable safeguard against food-pollution,
continued fairly prosperous ; and some of these exhibited
remarkable robustness in the ventral region (Hydreionocrinus).

A large number of crinoids were now in evidence with
clinging tentacles developed on the stem (Woodocrinus).
Probably the stem-roots were wasting away, and the out-
growths arose as helps to meet initial difficulties attending
emancipation. A few forms indeed — at least in the adult
state — seem to have gained a complete freedom to move
from place to place (Agassizocrinus). This was an advance
to modernism : for locomotion is enjoyed by the majority
of crinoids now living. The family, whose members had the
mouth exposed in the manner in vogue at the present time,
had increased in genera ; but as regards numbers and distribu-
tion it continued insignificant {IchthyocrinidcB).

Fossils occasionally contribute to decorative art : and
Carboniferous crinoids, like Devonian corals, have been
immortalised in beautifully patterned marble.

EVOLUTION IN THE PAST

Blastoids during this Period reached their cHmax, and
some very graceful forms appeared (Orophocnnus). Their
culmination, however, was not marked by any wonderful
display ; and they descended from their humble zenith with
some rapidity. By the close of the Period they seem one
and all to have collapsed ; and their annals, therefore, were
comparatively short. Possibly the somewhat complicated
breathing apparatus, which they had developed, proved un-
workable owing to changes in surrounding conditions.
STARFISHES Very little evidence has come down of Carboniferous star-
AND BRITTLE- fishes and brittle-stars ; but as their Devonian ancestors
STARS were not far short in development of modern forms, their
evolutions can only have been of a trifling character.

EA-URCHINS Rigid-tested sea-urchins of Silurian origin were still in
some force (Pal<2echinus). At this time, however, they were
being superseded by some closely related forms in body-
coverings with the plates constituted in more modem manner
(Melonites). Urchins in flexible tests were still numerous,
but flexibility had been considerably reduced in some cases
{ArchcBocidaris). Rigidity, it is clear, had long been the
pass- word through the ranks. So far as is known the plate-
rows on all tests, flexible and inflexible, continued excessive
in number compared with what ultimately became the rule.
SEA- Holothurians or sea-cucumbers, in skins embedded with

CUCUMBERS minute wheels, anchors, and other limy products, were
certainly now in being {Archistrum). Their precise line of
descent is obscure, but there is no doubt that they and sea-
urchins and all other of prickly group had descended from a
remote common ancestry. Their nearest relations in Car-
boniferous waters were probably the fast- vanishing cystids.

LAMPSHELLS The decline of lampshells does not seem to have been
arrested ; but these persistent animals made a good display
in many parts of the world. Some forms, moreover, of
record size now made their appearance. The most successful
at this time were those clinging to resting-places in shells
provided with long spines (Productidce). dingers of this kind
had appeared as early as the Silurian, but neither in that
nor in the succeeding Period were they much favoured by
fortune. Their prosperity, therefore, was long in coming ;

CARBONIFEROUS PERIOD

and when it came, the pent-up energy expressed itself not
only in vast numbers, but in some colossal forms. The
champion of the Period dwelt in a shell measuring nearly a
foot across (P. giganteus). Brachiopods in butterfly-shells
were also numerous, and flourished on European, North
American, and Asiatic coasts (Spirifer).

LampsheU-Hfe, therefore, although long past its prime, and
robbed of much of its old variety, was by no means going to
pieces.

No notable developments appear to have taken place polyzoans
among polyzoans. Open-mouthed colonies were stiU in
force on the sea-floor at various depths ; but they had
been surpassed in number by the later-developed com-
munities in which the zooids lived in cups partially protected
at the orifice.

Marine snail-Ufe exhibited some changes : but many old univalved
genera, dating as far back as the Cambrian, still held on molluscs
their way. A few new forms were now to be seen in shells
with loosely coiled tubes, rising in spiral fashion (Vermetus).
This development of the edifice, though peculiar, was not
unsuccessful, for some marine snails — of extremely passive
character — are still in tenements of this design.

Early types of scallops, wing-shells, ark-shells, and mussels, bivalved
and various double-shelled molluscs in intermediate con- molluscs
ditions of development were more fully and widely repre-
sented. The emigrants to brackish and fresh waters were
also on the increase.

Among the creatures combining pearl-oyster and mussel
affinities some very large forms were in evidence (Aviculo-
pinna) ; and oysters were appearing with which the edible
oyster of our own time retains more or less close relationship
(0. nobillisima).

Among new forms were animals of the date-shell type
(Lithophagus) ; and primitive file-shells were also to be
seen {Lima). Other forms were appearing with the edges of
the mantle modified into tubes or siphons for conducting
water to the giUs (Allorisma). These siphons could be with-
drawn completely within the shell-valves, and were probably
developed in connection with burrowing habits.

EVOLUTION IN THE PAST

Changes were going on in Cephalopod life. Several old
NAUTILOIDS genera had now disappeared ; but some nautiloids of long
descent, in shells more or less straight, were stiU in evidence.
These old-fashioned creatures, however, were being rapidly
superseded by nautiloids of later development, and shelled
more in the manner of the living nautilus.

But the greatest vigour of cephalopod life was moving
AMMONOIDS on the hnes disclosed by ammonoids of the last Period.

The transitional rod-like forms had now quite disappeared
{Bactrites) ; and the field was held by a variety of the coiled
forms known as Goniatites. The shells of these animals
remained for the most part with smooth surfaces, but in a
few cases were ornamented with knobs or tubercles (Gastrio-
ceras).

Efforts to render the shell more portable for crawling
purposes — observable in some goniatites of the preceding
Period — were unrelaxed : and the shell, in consequence of
the continued strain, was developing somewhat compUcated
patterns beneath the surface (Pronorites, etc.).
TRILOBITES No change of conditions favourable to trilobites occurred.

Only one small family — and that dating from Ordovician
times — now represented that ancient and once flourishing
Order {ProetidcB). The most prominent of its members were
small forms, slightly modified from their ancestors, chiefly
in regard to the tail (Phillipsia). Surely no beings other than
trilobites ever underwent so many head and tail changes in the
course of their career. Their lateral appendages, curiously
enough, always remained of primitive character.
SEA- Neither were the sea-scorpions enjojdng much better

SCORPIONS fortune. Apparently those strange creatures — giant forms
of which had appeared in the preceding Period — were now
represented only by small animals. Some of these, pre-
ferring fresh-water life, were frequenting streams and pools in
the forests.

Sea-scorpions seem to have died out in North American
waters during this Period ; but in Europe their extinction
took place somewhat later.
SHRIMPS Pod-shrimps were still declining ; and long before the close
of the Period they became extinct. Prawns, lobsters, and

CARBONIFEROUS PERIOD

crabs were still to come ; but their advent was foreshadowed
by various forms more or less resembling opossum-shrimps
(Anthrapalcemon, etc.). Other animals, slightly carapaced,
bore a close resemblance to mantis-shrimps (Necroscylla) ;
some (PrcBanaspides, Woodward), wholly without carapace,
resembled the mountain-shrimps now dwelling in rock-pools
of Tasmania (Anaspides).

Time had brought many changes among creatures above
the rank of invertebrates. The flat-headed, prickly
skinned little fishes, and several other Devonian types,
allied probably to sharks, had now died out. All the quaintly
armoured semi-fishes had also become extinct ; and a like
fate had overtaken the armoured fishes with jointed necks
(Arthrodira). There seems, indeed, to have been a process of
disarmament in operation ; and fishes, instead of being
provided with heavy protection for the skin, were to have
their gristly internal framework strengthened, and their
swimming powers improved.

Shark-like fishes were very numerous and widespread, sharks
Some of these (Acanthodes) were small creatures, less than a
foot in length, and belonged to a family first in view in
Devonian seas. These newer forms were probably quicker
in guiding movements, owing to the enlargement of the
breast-fins. Numerous blunt crushing teeth have also been
found, which belonged probably to sharks more or less
resembhng the mollusc-eating Port Jackson sharks of our
own day (Cochliodus). There were also fishes that appear
to have been diverging from sharks in the direction of rays
or skates (T amiohatis) : and a species of the family {RaiidcE) SKATES
seems already to have been in existence (Petalodus). In
addition to these there were some strange-looking forms
that appear to have been intermediate in development
between sharks and dipnoans or lung-fishes {Pleur acanthus).

Lung-fishes were more fully represented : but the new dipnoans
forms, except in being as a rule of larger size, differed but
little from their Devonian ancestors (Ctenodus).

Numerous modifications were going on in the ranks of crossopt-
the ganoids. Among the fringe-finned forms characterised, erygian
among other things, by paddle-like fins, none of the known ganoids

EVOLUTION IN THE PAST

Devonian genera had survived : and the outlook was not
very promising. In certain localities, however, some fishes
of this type measured from five to ten feet in length, and
were giants compared with earlier forms (Megalidhys,
Rhizodus). Others were more advanced in anatomy. An
improvement had been effected in the bony structure of the
skull ; and the tail was assuming a modern character. The
backbone was still of a gristly substance ; but certain
ossifications were going on within the body (Ccelacanthus).
Fishes of this well-equipped family held their own for a long
time.

The fringe-finned ganoids, however, were fast losing,
importance in consequence of the rapid on-coming of their
ACTINOP- " ray-finned " brethren. These more flexibly finned fishes
TERYGIAN — sparsely represented in the Devonian — were now becom-
GANOIDS ing numerous and varied. Some were long, herring-like
forms (PalcBoniscidcB) ; others had deep and more or less
compressed bodies {Eurynotus, Cheirodus). In their case,,
and indeed in the case of nearly all the ganoids, the end
part of the spinal column was upturned, and extended to the
extremity of the tail. The tail, therefore, was not of the
type best adapted for fleet swimming. Improvements in
this and other respects were in store.
AMPHIBIANS Fishes, progressing though they were, had ceased to be
in the van of vertebrate life. A momentous evolution,
originating no doubt in much earlier times, was now clearly
revealed by certain vertebrates possessing ability to breathe
by lungs, at least in the adult state, and to crawl about on
land. Amphibians, in short, had been evolved ; and various-
creatures resembling in form lizards, newts, and salamanders
were now on the scene.
(STEGOCEPHS) All these pioneers of higher life are known as stegocephs,
as their skulls and cheeks were well " roofed " over with
continuous bony plates. Very little is known about the
early Carboniferous forms ; but towards the close of the
Period the animals were in evidence on several lines of evolu-
tion. Some, of salamander shape, did not measure more than
two or three inches in length. These were triangular-headed,
large-eyed little creatures, weak in the limbs, and with

Kerater-
peton

Loxomma and Dolichosoina

CARBONIFEROUS AMPHIBIANS

[To face page 59

CARBONIFEROUS PERIOD

"backbones" incompletely ossified. The under-part of the
body was well covered with scales, affording protection in
creeping over hard ground (Branchiosaurus). Others, in
some cases four times the length, with elongated heads,
tapering snouts, and long tails, possessed fairly stout hind-
limbs, and the string of gelatinous tissue (notochord) running
through the length of the body was enclosed in bony cylinders
(Keraterpeton, Lepterpeton). In more advanced stegocephs,
the vertebral column was well ossified, and had undergone
divisional processes in order to render it more flexible
(Dendrerpeton). These were strong-limbed little creatures,
and probably penetrated far into the sylvan solitudes.
Besides these, some large amphibians were abroad with
skulls a foot and more in length, and with jointed backbones
completely ossified (Loxomma, Anthracosaurus). Their teeth
were remarkable, as numerous folds of the coating enamel
invaded the dentine or inner substance of the teeth in a
labyrinthine manner. These animals, known as labyrintho-
donts, appear to have been the most formidable members of
the new life ; and in the absence of serious competition they
doubtless fared sumptuously in their watery and riverside
haunts.

Then there were other forms — about a yard in length —
that had lost their limbs (Dolichosoma) ; and must have
somewhat resembled the limbless amphibians of our own
time (Apoda). They probably preyed on the fishes and
smaller stegocephs : and may occasionally have found them-
selves between the labyrinthine teeth of the lords of the
rivers and marshes.

That the stegocephs were evolved from fishes there can
be little doubt. Even at the present time amphibians retain
many affinities with fishes, and Carboniferous amphibians
held closer relationship with the fishes of their time. Their
nearest relatives appear to have been the fringe-finned
ganoids (Crossopterygians). These they resembled in several
anatomical respects, notably in the structure of the skull,
and in the hard plates round the eyes ; whilst the labyrin-
thodonts — the most important amphibians — possessed teeth
much as those of some of the fringe-finned ganoids. The

EVOLUTION IN THE PAST

earlier forms have come down to us less their limbs, but
from footprints left in the strata it is clear that the limbs
of some of them terminated with what may be called fingers
and toes. Most of the later Carboniferous amphibians
certainly possessed well-developed digits. The breathing
difficulty had, no doubt, been overcome more or less in the
same manner as with the lung-fishes. The animals in their
youth, it may well be supposed, breathed through gills, for
even in present-day amphibians lung-breathing is seldom
developed until the adult state is reached.

The Carboniferous strata, therefore, are not only remark-
able for their coal supplies, but also for the evidence they
yield of a well-developed and varied life of higher rank than
fishes.

PERMIAN REPTILES

I To face pngc 6i

PALEOZOIC AGE

PERMIAN PERIOD

Many new species of stegocephs were now to be seen amphibians

swimming the rivers, and crawling the marshes. Some were (stegocephs)

becoming of decidedly crocodilian aspect ; but, so far as is

known, they presented no essential differences from the types

of the preceding Period. Forms, however, much larger than

those of Carboniferous date were certainly abroad, especially

among those with teeth of " labyrinthine " structure (Labyrin-

thodonts). Some of these animals attained a length of nine

feet (Cricotus) ; whilst others with broad skulls of two feet

in length must have been of colossal proportions (Eryops).

These monsters were inhabitants of North American swamps

and rivers. The largest European stegoceph — a creature of

crocodilian appearance — was hardly as big as a monitor

lizard (Archegosaurus).

Some stegocephs with teeth of simpler construction
possessed what are known as abdominal ribs, i.e. transverse
fibres of ventral tissue faced with a bony substance (Petro-
hates). A protective development of this description is
characteristic of many reptiles.

But whatever may have been the reptilian tendencies reptiles
disclosed by some amphibians, a distinct divergence from the
ranks of the latter had taken place, for primitive reptiles
were now on the scene.

Most of these new leaders of life differed notably from
the " roofed-head " amphibians owing to cranial modifica-
tions. Their skuUs were not of the blocky type, but had
been hollowed out in parts, and made lighter and more refined.
These modifications had, no doubt, been accompanied by other
important changes, mental as well as physical.

EVOLUTION IN THE PAST

The respiratory system, owing to lack of evidence, cannot
be determined. Probably the animals did not breathe in
infancy by means of gills, as did the amphibians, but were
throughout life lung-breathers.

Some of these Permian reptiles scarcely attained a foot
in length (Palcsohatteria) ; but remains of more important
animals quite five feet long have been found in England and
Germany (Proterosaurus). These various animals must have
looked very much like lizards, and crocodiles, in spite of
anatomical differences. So far as can be ascertained the
lizard-like Sphenodon of New Zealand has not much departed
from them in structure. Indeed, that now-vanishing creature
may almost be looked upon as an unmodified descendant of
the founders of all the reptile race.
(thero- Towards the close of the Period reptile-life became diversi-
MORPHs) fied by various forms with marked resemblances to mammals,
not only in tooth, but also in bodily structure. These advanced
creatures have received the name of Theromorphs, or " beast-
shaped." Some in possessing well " roofed " skulls kept
up a connection with the stegocephs (Pareiasaurus). These
heavily skulled forms were probably of gregarious habits, and
spent a good deal of their time in the waters, subsisting
chiefly on aquatic plants. Many of them were big animals,
some forms attaining a length of several feet. No doubt they
were somewhat clumsy pedestrians when out on land-
excursions ; but they could when locomoting keep the
stomach clear of the ground. This was an achievement of
which a reptile might well be proud. They appear to have
been prosperous animals. Their range was certainly exten-
sive, for remains of them are found in regions so far apart as
South Africa and Northern Russia.

Their peace, it is to be feared, was occasionally disturbed
in some regions by certain big reptiles, likewise " beast-
shaped," but of a flesh-eating disposition. These thero-
morphs had skulls of the newer type, and their teeth were
decidedly more of a mammal than reptile character. Some
of these ferocious creatures — additional and important re-
mains of which have been recently discovered in Russia
(Professor Amalitzky, of Warsaw) — had tiger-like tusks

EDASOPHAURUS
A Permian crested reptile, about the size of a large sheep [To Jace page 63

PERMIAN PERIOD

(Inostransevia). As they were probably good swimmers,
and not indifferent pedestrians, the vegetarian reptiles
must at times have had their locomotive powers severely
taxed.

Some of the tusked reptiles, living in South Africa,
resembled lions in the shape of the skull (Dicynodon).
Apparently of the same race were certain tuskless and
toothless forms (Oudenodon). These, it is thought, belonged
to the gentler sex.

Other " beast-shaped " reptiles were remarkable for crests, (pelyco-
supported by spines rising vertically from the backbone saurians)
(Pelycosaurians). The crest was probably susceptible of
being raised or depressed ; and was only at its highest
elevation in times of excitement. In some cases the spines
were branched, and the raised crest must have had a broad
and hood-like aspect (Edaphosaurus).

The animals varied greatly in dimension, some (Edapho-
saurus) being the size of sheep, whilst others (Theropleura)
were as long as full-grown tigers. They all possessed strong
and weU-clawed limbs ; and could, no doubt, keep the body
clear of the ground when walking. Their haunts, it is sup-
posed, were along the banks of rivers and estuaries. Occa-
sionally they may have taken to the water ; but they were
not well adapted to aquatic life.

The broad-crested forms, to judge by their teeth, subsisted
chiefly on molluscs and vegetables. Most of the other forms
were of fierce carnivorous habits (Dimetrodon, etc.) ; and,
no doubt, waylaid small amphibians and reptiles incautiously
coming to land. At times they certainly became engaged in
serious hostilities ; for many spine-supports have been found
marked with ugly wounds.

Some members of the crested group lived in Europe ; but
the animals were in far greater force and variety on North
American scenes. Even there, however, their career was of
no great length ; and at the close of the Period they seem
to have become extinct on both continents.

In late Permian times several forms of " beast-shaped " (therio-
reptiles — sub-classed as Theriodonts or " beast-toothed " — donts)
exhibited marked resemblances to mammals in tooth and

EVOLUTION IN THE PAST

skull, and in some cases as regards the limbs {Cynognathus ,
Tritylodon, Theriodesmus).
(CHELONIANS) Other reptiles appear to have been developing on tortoise
lines, and were protected on the anterior part of the back by
several bony plates (Diadedes, Cacops). In some of the
smaller forms the plates seem to have covered the whole
back ; and, moreover, to have curved down on either side,
affording the animals an almost box-like protection (Oto-
cceeus, Conodectes). These creatures, it is clear, were intent
on a quiet life. The world was becoming troublous and
strifeful ; and a walled existence afforded some escape from
surrounding evils.

By the evolution of amphibians, fishes had lost the leader-
ship of life, and the rise of reptiles placed them still farther
from the van. In spite, however, of their humiliation, their
evolution was proceeding with some rapidity. Fish-life, in
fact, had never lagged ; indeed, so far as evidence goes,
it had come on with leaps and bounds from the time of its
first appearance. But in spite of rapid development, fishes,
at the close of the Carboniferous Period, had not undergone
much ossification of the internal gristly skeleton, and so fell
far short of the great majority of living fishes. Bony sub-
stance they certainly possessed, but this was more in the
hard scales than in the internal framework.
ACTINOP- It is in this Period that a glimpse is gained of some flexibly
TERYGIAN finned ganoids with internal skeletons that had in great part
GANOIDS become ossified (Acentrophorus). This improvement had
probably been effected at the expense of the hard scaly
covering. These fishes, moreover, had their median fins
more adequately supported than was the case with their
forerunners ; and the tail was losing its old unsymmetrical
(heterocercal) character. The upper lobe, hitherto much
elongated by the invasion of the spine, was becoming spine-
less ; and the short lower lobe was lengthening. The two
lobes were thus becoming symmetrical, and the end of the
" backbone " was being modified so as to provide them with
a common base. In other words, the tail was becoming of
the homocercal type, such as characterises the vast majority
of fishes now living.

PhUlipsia

PERMIAN MARINE LIFE

[To face page 64

PERMIAN PERIOD

These fishes were doubtless the most highly developed of
Permian forms, and were the forerunners of great develop-
ments in fish-life. As yet they were small in size, and
insignificant in number.

Meanwhile the other flexibly finned ganoids, with more
gristly skeletons, harder scales, and old-fashioned tails, were
greatly on the increase, being represented by old and new
genera (Platysomus, PalcBoniscus, Amblypterus).

The fringe-finned ganoids were still losing ground. But CROSSOP-
if, as seems likely, their Order had been more or less bound terygian
up with the evolution of amphibians, they were not sinking ganoids
into obscurity with dishonour.

Many old genera of fishes of the lung-breathing type had now dipnoans
disappeared ; and only two or three new genera made their
appearance (Conchopoma, Sagenodus). This division of fish-
Ufe had certainly lost importance, in spite of its double-
breathing abilities.

Nor do the sharks seem to have been enjoying much sharks
prosperity. Possibly such as subsisted on finny life had been
handicapped by the increased speed and wariness of their
prey. Some forms, however, that had appeared in the
Devonian, and had descendants with better-developed breast-
fins in the Carboniferous, were now represented by species
still better off in that respect (Acanthodes). But it cannot
be said that sharks were holding any remarkable sway in
the seas. They were, no doubt, the best brained of all the
fishes ; and sharks, indeed, enjoy this pre-eminence at the
present time.

The marine invertebrate life, so far as it is known, presents
few distinctive features from that of the last Period. There
is certainly not much progress to report in its fortunes.
Indeed, for the most part, it seems to have been in a greatly
depressed condition. The plight of some of its Orders is
intelligible enough, for signs of decay had long been in
evidence : but other groups that had been more or less
prosperous, and are known, moreover, to have fared well in
later Periods, seem for the time to have been wellnigh in
extremis. Not only do they appear to have diminished in protozoans,
numbers, but to have been reduced also in size. Even the etc.

EVOLUTION IN THE PAST

minute foraminifera were smaller than many of their ances-
tors in Carboniferous seas. Sponges were very poorly
represented. In coral-life reef-building was almost brought
to a standstill. Starfishes and brittle-stars seem to have
been quite under a cloud. Cystids, long languishing, died out
early in the Period. Great havoc had been wrought in sea-
lily ranks. All the sanitary reformers apparently had been
wiped out : and crinoidal fortunes seem to have been in the
keeping of an old family that had struggled on from Ordo-
vician times (CyathocrinidcB). But it was not all a catalogue
SEA-URCHINS of woe. Sea-urchins of Devonian type, both flexible and
inflexible, had indeed been nearly exterminated ; but " rude
forefathers " of some modern urchin-families were just
beginning to appear. These were enclosed in rigid tests,
with vertical plate-rows reduced to the number that now

POLYZOANS obtains (Hemicidaris, Cidaris). Polyzoan colonies were in
great force. Those of the open-mouthed type had recovered
their ascendency ; but the rival group was well in evidence
LAMPSHELLS (Fenestello). Brachiopods or lampshells, though reduced in
variety, made a good display, especially in Asiatic waters.
Species with anchor-spines continued most prominent ; but
no giants were now in their ranks (ProductidcB). Other forms
in " butterfly " shells — also much in evidence in Carbonifer-
ous seas — were abundant (Spirifer) ; and several other
lampshells of remote lineage were still clinging to the rocks.
BiVALVED There is no great progress to report among bivalved
MOLLUSCS molluscs ; but they attested their character as a rising group
by new forms of ark-shells (Schizodus) ; and by the evolution
also of some small forms {Bakewellia), founders of a present-

UNIVALVED day family of pearl-oysters (PernidcB). Univalves exhibited
MOLLUSCS little or no progress. The most prominent at this time were
creatures in bell-shaped shells of Silurian pattern (Bel-

NAUTILOIDS lerophon). Apparently all species of nautiloids in slightly
curved shells had died out ; and those in straight shells were
represented by only one genus that had persisted from the
Cambrian (Orthoceras). Several genera, however, in shells
more or less resembling the coiled shells of the hving nautilus,
were about the seas (Stenopoceras, Pselioceras) ; and the
long competition between the " uncoiled " and the " coiled "

PERMIAN PERIOD

was thus terminated by the decided predominance of the
latter.

Ammonoids — the most recently developed cephalopods ammonoids
— were exhibiting all the adaptability of young life. Gonia-
tites were disappearing, or at least, by an increased porta-
bility of the shell, were being transformed into ammonites.
This is evidenced by the twisted and complicated patterns
which were now being wrought beneath the shell-surface
(Medlicottia, Xenodiscus). Outward ornamentation of the
shell was also becoming a feature.

Trilobites — so widespread and varied in the past — were trilobites
now represented by only one or two species that soon became
extinct (Philli-psia). Sea-scorpions were also but feebly sea-
represented (E. remipes) ; and likewise vanished in the scorpions
course of the Period. To redress the balance some very small
creatures, developing apparently in the direction of lobsters crustaceans
and crabs, were now beginning to appear {Hemitrochi-
schus).

Marine invertebrate life may not, of course, have suffered
so greatly as the geological record leads one to surmise ; and
discoveries may yet be made which will point to its having
been in a much less impoverished condition. There is,
however, good reason to suppose that in some regions,
especially in the southern hemisphere, Permian life for the
most part laboured under exceptional difficulties. At the
commencement of the Period, and more or less until its close,
severe glacial conditions prevailed over vast areas, that had
for long enjoyed mild and equable climate ; and the results
to life must have been disastrous.

Vegetation, without doubt, was greatly affected ; and vegetation
some growths, long accustomed to humid and relaxing airs,
having lost their pristine powers of ready adaptation, were
in a parlous state. The progress, however, of growths of
newer type and of more elasticity was, it would seem,
expedited.

Calamites or " horsetails " certainly suffered ; and the
branching tree-like club-mosses, and their pillar-like allies
dwindled almost to extinction (Lepidodendra, SigillaricB).
The endeavour of certain Carboniferous lycopods to steal a

EVOLUTION IN THE PAST

march on other club-mosses by producing seeds instead of
spores had resulted in complete failure ; and no ambitious
speculations in reproduction were again attempted.

Several new genera of ferns were superseding those of
earlier times. In the southern hemisphere and also in
northern Russia some hardy species with simple leaves
variously shaped became abundant (Glossopteris). In northern
Russia certain ferns by stem and leaf-stalk modifications
exhibited important advances in development, indicating a
greater division of labour {Zalesskya, Thamnopteris). Cycad-
ferns continued numerous, but were now yielding to forms
not far short of being true cycads (Pterophyllum, Sphenoza-
mites). Meanwhile the old flower-bearing cordaites were fast
succumbing.

CONIFERS The most notable Permian growths were of true conifer
character. Primitive conifers — derived from plants of the
Cordaite type (Cordaitales) — were probably, at least in sparse
numbers, in Carboniferous woodlands ; but the stability of
the line was not well established until late in the Permian
Period. Many well-developed forms then adorned the land-
scapes : and although they differed in some respects from
living conifers, they can be brought more or less into line
with them. Some were closely allied to cypresses and
araucarias ( Walchia, Ullmania) ; some to spruces and
Sequoia firs (Voltzia, Schizolepis) ; and some to yew, and
gingko or maidenhair trees (Baiera, G. primigenia). These
various growths, however, brought no bright colours in their
train ; and vegetation remained of a dull, monotonous hue.
Nor were there as yet any birds, or even butterflies, to relieve
the sombrous scenes.

This brings us to the close of what is known as the Palaeozoic
Age. This Age with its six Periods must have lasted many
millions of years ; and was probably more than thrice as
long as all the time that has elapsed since its close.

Progress, if slow, was sure. Plant-life, consisting in the
Cambrian probably of algae, funguses, lichens, liverworts,
and other humble spore-producing growths, underwent in
time various modifications, resulting in ferns, " horsetails,"
and club-mosses. Then came seed-bearing cy cad-ferns and.

PERMIAN PERIOD

cycad-conifers ; and finally shrubs and trees comparable
with cycads and conifers of our own time.

Invertebrate life at the close of the Cambrian was certainly
well represented in its existing main divisions ; and during
succeeding Periods of the Age great developments went on
within its varied ranks.

There were also some notable examples of what seems to
be the fate of all forms of life on earth. Cystids and blastoids
rose, declined, and became extinct. Lampshells reached a
grand zenith, and then entered on a downward path. Trilo-
bites, after attaining vast variety of form and world-wide
distribution, slowly declined, and utterly passed away. And
sea-scorpions experienced, on a smaller stage, a like cycle of
fortune.

From invertebrate ranks fishes gradually emerged, and,
after a rigorous Natural Selection, some forms with greatly
improved swimming powers, and with stronger internal
framework, came into evidence. In course of time amphibians
— evolved from certain of the fishes — made their appearance,
and branched out into several types. And finally from
amphibian ranks reptiles came forth, and took up the
leadership.

In spite, therefore, of retrogressions and destructions, of
waste and suffering, the main movement in Life was dis-
tinctly onward. Nor were signs wanting at the close of the
Permian of coming great developments.

MESOZOIC AGE

TRIASSIC PERIOD

VEGETATION Triassic landscapes bore witness to great conquests made
by the newer vegetation. Various growths more or less
allied to araucarias, spruces, Sequoia firs, yews, cypresses,
and maidenhair trees extended far and wide, and abounded
with species. Club-mosses and " horsetails " struggled on
with but scant success. Among the latter were some scarcely
distinguishable from the modern degraded forms {Eqiiisetum).
Pillar-like sigillariae — rampant in Carboniferous forests — had
almost disappeared : and the old-fashioned, wedge-leaved
climbing growths of mixed affinities had quite died out
(Sphenophyllum).

FERNS Ferns, however, although of ancient standing, continued
to spread with the vigour and resource of earlier days. Many
Carboniferous genera flourished as of old ; and new forms of
like character (Eusporangiates) — some closely related to the
existing " Adder's Tongue " (Chiropteris) — were also un-
rolling their fronds in the tangled undergrowth. Other
debutants exhibited improvements in spore-case construc-
tion, and produced their spores in a more speciahsed and
complex manner than did the older forms. These more
advanced ferns were undoubtedly forerunners of the now
prevailing type (Leptosporangiates). Towards the close of
the Period some (AcrosHchites princeps) but httle distinguish-
able from " Royal ferns " (Osmunda regalis) were luxuriating
in marshy lands, and adorning the banks of lakes and
streams. Others appear to have been precursors of the
Polypods — the dominant fern family of our own time
(Cladiophlehia).

TRIASSIC PERIOD

The flower-bearing cordaites had failed in their compe- cordaites
tition with other seed-producing plants, and had become
extinct ; whilst cycad-ferns had been entirely superseded cycad-ferns
by offshoot forms describable as true cycads. The latter as
a rule were short-stemmed plants, but some bore their
feathery crowns on stems ten feet in height.

Cycads, moreover, were in evidence on various paths of cycads
development. Some seem to have been on the lines of the
modern Zamia (Zamites) ; others on the lines of the Australian
Cycas. The most remarkable of all are not now represented in
the plant world (BennettitecB) ; and they were of much higher
organisation than any cycads now living. Fair-sized star-
like flowers, possibly of greenish hue, stood out among the
foliage ; and the fruit resembled in structure that of angio-
sperms — the most highly developed of living plants. The
seeds, therefore, being enclosed or " vesselled " in an ovary,
were much better protected and cared for than the " naked "
seeds of conifers. Apparently these highly developed cycads
held the leadership in the leafy world : and the greater care
they took of their seeds marked an advance in what may be
called the morality of plant -life.

How far insects were assisting in the development of insects
vegetation it is impossible to say. Doubtless these little
creatures were increasing in variety, and changing their
tastes and habits from time to time. Various kinds of beetles
were certainly now in existence {Carahidce, BuprestidcB,
etc.) ; but bees and butterflies, so far as is known, were
yet to come ; as were also the various flowering plants
to which they are specially helpful in the matter of
fertilisation.

It will be necessary to return to Triassic lands. Mean-
while our glance must be directed to the submerged
masses.

Invertebrate life — no longer in a pitiable condition —
attested the sweet uses of adversity. Sponges with lime sponges
spicules — first known in the Devonian — were flourishing in
various shapes and sizes {Eudea, etc.). They seem to have
been especially prosperous in central Europe, a large portion
of which was at this time under water.

EVOLUTION IN THE PAST

CORALS Many old forms of corals had passed away ; or, if they
can be said to have survived, it was only in modified
descendants. One family (Poritidce), which came in view in
sparse numbers in the Carboniferous Period, was now
markedly in the ascendant. The success of these corals was
probably due to their possessing perforated body-walls, and
their enjoying, therefore, a greater community of life. At the
present day their descendants are in great evidence on the
Australian barrier-reef.

Many colonies were also in existence composed of corals
in solid body-walls : and descendants of some of these less
socialistic communities are still living (Stephanocoenia).
SEA-LILIES Crinoids, or " sea-lilies," were slowly recovering from
Permian afflictions ; but their convalescence was no prelude
to a renewal of whilom vigour. They were certainly more
modern in structure. This may be gathered from the manner
in which the " arms " were attached to the cup ; and from
the fact that the exposed mouth — rare in earUer times — had
become general (EncrinidcB, PentacrinidcB).
SEA-URCHINS The lead in " spiny-skinned " Hfe was in this Period
being taken by sea-urchins. With most of these the body-
covering had been consolidated into twenty vertical rows of
plates — the regulation number at the present day. A few
reactionary forms with more than twenty plate-rows appeared
occasionally in later times ; but sea-urchins in tests of that
character practically made their last appearance in this
Period.

POLYZOANS Among Polyzoans, the colonies with zooids in open-
mouthed tubes had entirely eclipsed those in which the
zooid-tubes were " hidden-mouthed." Indeed there is little
or no evidence that the latter colonies were even in existence.
There is, however, reason to think that they were undergoing
important improvements, the installation of which was
involving them in temporary difficulties.
LAMPSHELLS Brachiopods were still on the downward path. More
families had become fossil : but some of long standing and
noted for well-beaked shells, were exhibiting no little vigour
(RhynchonellidcB, TerebratulidcB).

Bivalved molluscs retained, in great part, a mixed and

TRIASSIC PERIOD

archaic character, but fresh threads, so to speak, were bivalved
coming out of the tangle. Some forms in the last Age had molluscs
been developing in the direction of mussels ; and fresh-
water and sea mussels of modern type were now in being
{Unto, Mytilus). New forms of ark-shells were also in view ;
some of which are still represented in the mollusc world
(Limopsidce). Oysters somewhat of the " thorny " kind
were also on the scene (Plicatula) \ and cockles, which had
more or less given sign in the last Age, were now rid of old
partnerships, and established as a distinct family (Cardiidce).
Among the bivalves with long, retractile siphons, new forms
were to be seen (Corhula). These appear to have been of the
type of the " gaper " molluscs of our own time (Myadce),
with " feet " too large for their shells.

Gastropods fell far short of the bivalved molluscs in point univalved
of number : and it was a very long time before they equalled, molluscs
and finally surpassed them. The mental superiority of
snails to bivalves may not have been so great then as
now.

The most noteworthy fact in the Triassic annals of gastro-
pods was an elaboration of the breathing system in certain
species. Most of the marine snails then living probably
breathed entirely through the skin, as do some of the
fraternity at the present time. Some forms possessed gills
as additional means of respiration ; and it was in the
case of certain of the gilled snails that notable changes
had taken place. Aerated water had, of course, to be carried
to the fold in the mantle where the gills were located ; and
this had hitherto been done through the agency of modified
edges of the mantle. Under the new arrangement the work
was being done in a more cleanly and efficient manner by
means of a well-defined tube or siphon (CerithiidcB).

In spite of the multiplications and deployments of bivalves,
and the on-coming of univalves, cephalopods continued the
leading molluscs. Their adaptive powers were certainly
great, and they were probably the " intellectuals " of the
mollusc world. How far their mental development was
accelerated by the habit of walking more or less on the head
cannot be determined.

EVOLUTION IN THE PAST

NAUTILOIDS Some old-fashioned, straight-shelled forms were still in
existence (Orthoceras) ; but their protracted annals were
now about to close. Coiled nautiloids held an easy domin-
ance ; and some old species that had been slowly developing
into the condition of the living Nautilus had now almost
reached the goal.

AMMONOIDS The greatest activity in development was among the
Ammonoid cephalopods. The Goniatites had wellnigh dis-
appeared, or been transformed ; and practically all Triassic
members of the Order may be described as Ammonites. The
creatures, as a rule, had their shells in a far more portable
condition, as shown by the complicated sub-surface patterns.
These twisted markings had assumed ornate characters, and
resembled in many cases small foliage delicately indented
(Phyllocampyli). In addition to this concealed beauty, many
shells, owing to modifications on the edge of the mantle or
body-skin, were highly decorated on the exterior (Pachy-
campyli).

Conditions were extremely favourable to ammonites for
the greater part of the Period. They abounded in an im-
mense variety of forms, their shells differing not only in
sub-surface tracery, and outward ornamentation, but also in
shape and strength.

Their range was world-wide, and they certainly attained
their climax in this Period, but before its close some signs
of breakdown became evident.
BELEMNITES Just as these signs were appearing, Cephalopod-life was
recuperated by the rise of creatures not greatly differing
from squids and cuttle-fishes. They are generally spoken of
as belemnites — a name derived from the dart-like appearance
of their shells {Belemnitidce). The shell, in being straight and
tapering, exhibited a notable difference from the ammonite
shell. It had, moreover, by a reverted extension of the mantle
or body-skin, become internal.

Triassic belemnites were few in number, and small in
size — the largest not being more than a few inches in length..
As a rule they were provided, like cuttle-fishes, with ink-sacs,
for clouding the water and confusing foes.

The origin of the animals is lost in obscurity. Their nearest

TRIASSIC PERIOD

relatives in Triassic seas were probably the straight-shelled
nautiloids, rapidly passing away (Orthoceras).

The Permian promise — if promise it was — of the appear- crustaceans
ance of crabs was not fulfilled. Crustaceans, however, were
now in view with much nearer resemblance to prawns and
lobsters than were the " pod-shrimps " and opossum-shrimps
of earlier times (Pemphix).

King-crabs — called crabs by courtesy — were now in exist- king-crabs
ence with a second shield developed. These animals appear
to have been identical in structure with the modern King-
crab (Limulus). The half-formed creatures, with front-shields
only, seem by this time to have died out.

Triassic King-crabs were diminutive creatures ; but the
departure of their ancestors from the doomed and afterwards
overthrown trilobite ranks had ensured survival.

Fish-life, different though its aspect from that of modern
times, was making headway.

Sharks, after serious reverses in Permian seas, were now sharks
abroad in new genera, and in great abundance (Hyhodus,
Acrodus, Strophodus). And less predaceous fishes were enjoy-
ing prosperity, not only in spite of old foes, but in the face
of new dangers which will be noted presently.

The old " fringe-finned " ganoids with paddle-like fins ganoids
were still waning (Crossopterygii). This Order had apparently
played its part — and a great one — in giving rise to primitive
amphibians.

Among the more flexibly finned ganoids (Actinopterygii)
old and new genera were now to be seen. The most notable
absentees were certain deep-bodied forms such as had
flourished in Carboniferous and Permian seas (Eurynotus,
Platysomus). Among new forms may be mentioned some
gristly skeletoned fishes with hard enamelled scales (Catop-
terus, Dictyopyge), and akin to some fishes of Permian times
(PalcBoniscus, etc.). They, however, showed advance in
development over their forerunners in having the dorsal and
anal fins more effectively supported. Their tails, moreover,
were of less antique character, in being to a certain extent
free of the spinal column. In some closely allied pike-shaped
forms an ossification of the spine was well in progress ;

EVOLUTION IN THE PAST

but these did not exhibit in other respects notable
advance over their Permian predecessors {Belonorhynchus,
Saurichthys).

The most interesting ganoids were some highly developed
forms, a few forerunners of which had appeared in the
preceding Period (Acentrophorus). These possessed vertebral
columns well ossified, dorsal and anal fins adequately sup-
ported, and tails that were assuming modern character.
In short, they possessed all the features of progress evi-
dent in fish life ; whilst no other fishes possessed them in
entirety.

Fishes of this type — so rare in the Permian — were now
varied and numerous (Semionotus, Lepidotus). They were
for the most part of strange aspect, and not closely com-
parable with living fishes. Some very small forms bore a
resemblance to herrings (JPholidophorus). Other forms
(Caturus) in some respects strongly resembled the bow-
fins of our own time (Amia).

At the close of the Period these various members of well-
advanced fish-life became fairly abundant ; but their less
highly developed relations — suggestive of bottles too old to
hold much of the new wine — continued predominant.

Curious old forms, intermediate in development between
sharks and lung-fishes (famous in Carboniferous and not
insignificant in Permian seas), had now become practically
DIPNOANS extinct (Pleur acanthus). Among dipnoans a few forms had
now reached a point at which they differed very little from
the Australian " mud-fish " of to-day (Ceratodus). In
Triassic times " double-breathers " were abandoning salt
water for brackish and fresh. And in this Period the}^ practi-
cally made their last appearance as marine fishes.
AMPHIBIANS The lizard-like Stegocephs were now represented by a
variety of forms (Capitosaurus, Trematosaurus). Large-eyed
monsters, too, were among them, with skulls of more than a
yard in length (Mastodonsaums). Those with teeth of
elaborate structure, and named Labyrinthodonts, had greatly
increased. Indeed practically all Triassic stegocephs, it
would seem, belonged to that group. They were more highly
developed than their Permian predecessors, as their back-

TRIASSIC PERIOD

bones were well- jointed and ossified : and their tooth-enamel
was infolded in a still more complex or labyrinthine
manner.

Although hard pressed by reptiles they were able to keep
up a good front for the greater part of the Period. Towards
its close they dwindled into utter insignificance ; and the
heroic days of amphibians came to an end.

Among reptiles remarkable developments were taking reptiles
place. The creatures, however, were still in what is termed
a generalised condition ; that is to say, it was as yet un-
certain what particular forms of animals their descendants
by successive modifications might become. They stood, in
short, at the parting of the ways. New forms, not greatly
differing from the Sphenodon semi-lizard type of earlier
times, were appearing (Telerpeton, Hyperodapedon) ; and
they ranged from western Europe far into Asia. Other forms
— remains of which have been found in Europe and North
America — seem to have been developing in the direction of
long-snouted crocodiles (Belodon). At the same time they
possessed features in common with dinosaurs — the " terrible
lizards " that were just beginning to appear. Certain small
forms — ^not much more than two feet in length — seem to have
been committed to a more or less crocodilian development
{Aetosaurus).

The well-crested reptiles no more graced the scene
{Edaphosaurus, Dimetrodon, etc.). But descendants of
certain " beast-shaped " Permian reptiles, with vegetarian
tastes, were in great force (Pareiasaurus). By going about
in large companies, these animals no doubt enjoyed greater
security, but the flesh-eaters were also represented by
numerous descendants, deeply imbued with family traditions
{Inotransevia, Dicynodon, etc.). Possibly in response to this,
some small " beast-shaped " vegetarians were now to be
seen with heads grown fearsome with bony excrescences
(Elginia mirahilis).

In addition to these various reptiles, some allied but quite dinosaurs
distinguishable forms known as Dinosaurs, or " terrible
lizards," were now in existence. Their range was already
extensive, for remains of them have been found in Europe,

EVOLUTION IN THE PAST

South Africa, India, and North America. These strange
•* creatures had well-developed hind-limbs ; whilst their " arms"
were comparatively short. The latter, no doubt, were
chiefly used for seizing and holding prey ; and locomotion
was effected, somewhat in kangaroo fashion, on the hind-
limbs only. Facility for agile and speedy movement was
certainly afforded by the hoUowness of the limb-bones
{Zanclodon, Euscelosaurus, Epicampodon). The animals
varied a good deal in size : some remarkable forms, with
bird-like skulls, must have stood between five and six feet
in height (Anchisaurus).

The precise line of dinosaurian descent is unknown. All
the Triassic forms seem to have been carnivorous ; and
they haunted, no doubt, lake-banks and riversides ; and
victimised the tender and neglected offspring of amphibians
and also of fellow-reptiles.
\ Dinosaurs, so far as is known, were the first bipeds to
appear on earth — the first creatures to stand and move
about in a fairly erect position. They come, in fact, within
Plato's special definition of a man — " a biped without
feathers." Dinosaurs, therefore, were not dreamt of in his
philosophy.

PLESio- Other reptiles, now first in view and known as plesio-

SAURIANS saurians, betrayed no inchnation to bipedalism ; and when
on land must have moved about in a somewhat laboured
A manner. They were undoubtedly good swimmers, and when
afloat must have had an appearance such as swans, deprived
of feathers and suffering from stiff necks, would present.
They had probably descended from some forms that had been
more or less permanent land-dwellers. Possibly their remote
ancestors were some land-frequenting stegocephs of Car-
boniferous times. Terrestrial life, it would seem, had lost its
charm ; and these Triassic descendants were experimenting
in water, and possibly becoming experts in fishing. Many
of them were of small size ; but here and there creatures
were to be seen varying in length from four to six feet
{Lariosaurus , Nothosaurus).

Plesiosaurians were much more developed in the next
Period : and it is interesting to note that these Triassic

ICTHYOSAURS AND BELEMNITES

[To face page 79

TRIASSIC PERIOD

creatures probably still spent a good portion of their time on
land. This may be inferred from the limbs not having
acquired that complete paddle structure which characterised
the later forms.

Other reptiles known as ichthyosaurs or " fish-lizards " ichthyo-
— also probably descended from land-haunting ancestors — saurians
had certainly gone steps further from terrestrial life, and had
become whale-like in shape (Mixosaurus). They were short-
necked, long-jawed creatures, with sharp, conical teeth. The
tail in its lower lobe was possessed to its extremity by a sharp
down-curvature of the spine — a curvature reverse in direction
to that in the old-fashioned fish-tail. This novel construction,
no doubt, facilitated the ascent of the animal when seeking
the surface for fresh supplies of air ; but it cannot have been
so efficient for that purpose as the tail with horizontal
lobes such as whales possess. All four limbs to out-
ward appearance were fins or paddles ; but fingers and
toes, although undergoing modifications, were still defined
within.

The largest of the Triassic forms did not exceed a yard
in length. They were doubtless consumers of fishes ; but
they developed a great partiality for belemnites. These
they must have found highly nutritious, as will be seen
later.

Forerunners of tortoises had appeared in the Permian chelonians
Period ; and this Order of reptiles was now represented by
animals not far short in development of modern forms. The
ancestral sluggishness had been confirmed ; and an unearned
increment of armour-wealth had resulted. There seem to have
been both " hidden-necked " (Cryptodira) and " side-necked "
(Pleurodira) animals as at the present day — some that could
telescope the neck and envelop the head in the box-like
armour (Chelyzoon), and some that could only shelter the
head by bringing it round under the side-edge of the upper
shield {Proganochelys, Pleurosternum).

Triassic chelonians probably spent placid, uneventful lives
in the swamps and rivers, and never ventured out to sea.
They doubtless had foes among the less lethargic reptiles ;
but they were fairly safe within their bony walls.

EVOLUTION IN THE PAST

With primitive lizards, crocodiles, dinosaurs, plesiosaurs,
" fish-lizards," and tortoises on the scene, there was, it must
be admitted, a wonderful display of reptile life. But these
creatures, although highly and variously developed, were
not — at least in the latter part of the Period — the highest
life-forms on earth : for at that time Mammals were certainly
in being.

It is not possible to picture the appearance of these
prototheres or " first beasts " as they are named ; for there
is nothing to recall them save some jaws and teeth, and a few
bones, found in Europe and North America (Dromatherium,
Micronodon, Microlestes). They do not appear to have been
larger animals than rats and mice. Some of them were
probably constituted like the Australian ant-eater (Echidna),
laid eggs, and nourished their young with milky juice oozing
from the breast ; whilst others probably brought forth
young of minute size, and carried them about in pouches
after the manner of marsupials.

These primitive creatures must have been in frequent
danger from carnivorous reptiles ; but they doubtless sur-
passed reptiles in some important respects. Reptiles, as a
rule, are sluggish animals ; their brain power is of humble
calibre ; and their moraUty, as judged by the little or no
care they exhibit for their offspring, is equally low-pitched.
And it is probable that the Triassic reptiles had similar
shortcomings. On the other hand, these primitive mammals
were probably nimble and active little creatures, with a
relatively high intelligence, and keenly solicitous for the
welfare of their young. These attainments were bound to
tell in time, unless creation rested simply on brute force.

" Whence," one may naturally ask, " were these types of
higher hfe evolved ? " There is little or no doubt they were
evolved from reptiles, probably from some very small " beast-
shaped " forms (Theromorphs) ; and from such of those as
had teeth of a more or less mammahan pattern (Theriodonts).
At least no other descent so probable as this can be given.

The appearance of mammals was indeed an event of the
highest significance. Nature after successive stages from
marine invertebrates to fishes, amphibians, and reptiles.

TRIASSIC PERIOD

had embarked on a course destined to result in a wonderful
development of life. Here, too, was Morality in active
evolution, breaking like sunbeams through clouds. Animals
had appeared, parts of whose bodies were designed, not for
their own convenience and welfare, but for the use and
benefit of their offspring. Altruism had passed to a higher
stage ; and many virtues, hitherto obscured or undeveloped,,
were coming forth as lights in the world.

MESOZOIC AGE

JURASSIC PERIOD

SPONGES The annals of marine invertebrate life, if humble, were not
uneventful. Sponges were in great force. Some six-rayed
forms now had their needles arranged into a highly complex
network (Craticularia) ; and among the four-rayed some
thick-walled, cylinder-shaped forms of modem type were
making their appearance (Cylindrophymd).
CORALS Corals do not seem to have made much headway during
the early part of the Period ; but in the course of its long
years, reef-building corals — both perforate and non-perforate
— ^became more abundant than ever. In central Europe, a
very large part of which was submerged, they seem to have
spread far and wide over the sea-floor.

Some new non-perforate forms were in the seas with cups
divided up with numerous partitions in the manner of a
fungus-cap (Fungidce). These and other families, first known
in this Period, have persisted until the present time (Stylo-
phoridcB, TurbinolidcB).
SEA-LILIES Crinoids or " Sea-lilies," after a somewhat chequered
career ever since the close of the Silurian, were now reviving.
Modernised forms, such as had appeared in the Trias, seem by
this time to have practically superseded aU the older-fashioned
types. No trace has been found of sanitary reformers, con-
spicuous in earlier times with cumbrous waste-pipes.

Some of the fixed sea-HUes, hitherto confined to the shal-
lows, were at this time spreading out into comparatively
deep waters (Eugeniacrinus). Forms free and stemless — at
least in the adult state — were certainly on the increase
(Antedon, etc.). At the same time there were stemless
crinoids which apparently had no desire for a free life.

JURASSIC PERIOD

Although they had lost their stems, they held fast to the
sea-floor by means of a small outgrowth at the base of the
cup (Cotylederma). Crinoids of this character are still living
in the Caribbean Sea (Holopus).

Many of the Jurassic starfishes seem to have been in- starfishes
distinguishable from species now living (Asterias, Astropecten,
Luidia). Some new forms were appearing in which the
central disc was being extended into the spaces between the
arms ; and the animals presented a five-sided cushion
appearance (Goniaster). These, no doubt, were ancestors of
the so-called " cushion-stars " of our own day. Some other
forms had exceeded the numeral characteristic of the Order
— and indeed of all " spiny-skinned " animals — by develop-
ing more than five arms {Solaster). Starfishes of this
heretical description have continued until the present day,
and are represented by " sun-stars " of many genera.

Brittle-stars had undergone some trivial modifications ; brittle-
and certain of the creatures were apparently identical in stars
structure with brittle-stars now living (Ophioglypha).

Although " sea-lilies " were reviving, and starfishes and sea-urchins
brittle-stars were assuming modern aspect, sea-urchins con-
tinued predominant among the "spiny-skinned" inverte-
brates.

The most notable feature of Jurassic sea-urchin life was
the appearance of many forms no longer characterised by
globular tests. Numbers were now in existence in flattened
and four-sided body-coverings (Clypeus, Echinobrissus) ; and
the mouth was being brought forward from its old central posi-
tion on the under-part of the test. These modifications of the
test point, no doubt, to changes of habit on the part of the
animals. In locomotion, for instance, the test would neces-
sarily become exposed to special resistance from the sur-
rounding medium, and tend, therefore, to lose its globe-
shaped symmetry. This would markedly be the case where
boring and crevice-haunting habits were being adopted.
And there can be little doubt that many Jurassic sea-urchins
spent less sedentary, open-water lives than their ancestors,
and also indeed than most of their contemporary brethren.

A few new forms, reviving an old fashion, were now

EVOLUTION IN THE PAST

appearing in thin and flexible body-coverings (Pelanechinus,
Keeping). Successors of these in the next Period (Echino-
thuria, S. P. Woodward) closely resembled some sea-urchins
now living {Calveria).
POLYZOANS The annals of polyzoans have not been very well preserved
in the rocks ; but there is evidence that some of the com-
munities had undergone important modifications. Vast
numbers of colonies with individuals in open-mouthed tubes
were living in the seas ; and were very similar, to their fore-
runners. The rival colonies, however, exhibited a great
improvement. In these communities the orifice of the zooid-
tube, instead of being provided as formerly with a small
shaft, was furnished with a movable lid. The zooid, there-
fore, could at will keep the entrance to the tube open or shut
(Chilostomata), and so possessed more control over its
destinies. In some forms the lid improvement had only been
partially effected.

The " open-mouthed " colonies, however, in spite of their
more primitive tubes, were far more prominent than their
rivals. There is little doubt indeed that the latter had
undergone great trials in the course of their reconstruction.
LAMPSHELLS Brachiopods continued to decline, but several old families
maintained a stubborn front against " the sHngs and arrows "
of fortune. This was notably the case with well-beaked
brachiopods — much in evidence also in the Trias. Brachio-
pods in " butterfly " shells — with an ancestry running back
to Silurian times — were still in existence {Spiriferina) ; but
they had little enough oil, so to speak, left in their lamps ;
and before the close of the Period their feeble lights all
flickered away.

BiVALVED Bivalves were manifesting their adaptive powers in many

MOLLUSCS new developments.

Oysters of various forms were now in being ; and in some
regions they were gathered together in beds in the manner of
modern oysters (Ostrea, Exogyra). Many of them were
enclosed in shells curiously twisted by the growth of big
beaks, developed, it may be supposed, in connection with
fixation purposes (Gryphcea). Thorny oysters, vaguely loom-
ing for some time past, seem now to have reached a state

JURASSIC PERIOD

generically identical with that of their living brethren
(Spondylus). Other forms appear to have been what are now
known as " edible " oysters. They were probably relished,
at this time, mainly by whelks and starfishes.

Pearl-oysters were here, with their beady products (Melea-
grina). Clams also were to be seen ; but they did not much
resemble modern forms {Diceras). File-shells, of which
forerunners had appeared as early as the Carboniferous
Period, were now abroad of much larger size {Plagiostomd).
" Ship- worms " — molluscs so-called from their affection for
boring into floating timber — had also appeared (Teredo) ;
and doubtless gratified their tastes on flotsam tree-trunks
from the forests. Other bivalves were forerunners of Venus-
shells, and tellens ; and if their shelly coverings were as
gaily painted as those of their living descendants, their
collecting-grounds must have mirrored as flower-beds sub-
merged (Venus, Tellind).

Gastropods still differed in many respects from living UNIVALVED
forms. It is interesting to note that those provided with molluscs
a siphon apparatus had clearly derived health and strength
from the contrivance. Such marine snails were vastly more
numerous than in the Trias ; and among them were forms
recognisable as cowries, pelican-foot, and scorpion shells
(Cyprcea, Aporrhais, Harpagodes).

Ammonites continued predominant among cephalopods, ammonites
and indeed among all marine invertebrates. Some Triassic
families were still represented ; but most of them had either
been suppressed or transformed. Evidence of breakdown,
visible in a slight degree at the close of the Trias, was now
more marked. The adaptive powers, however, of the animals
were still far from being exhausted ; as evidenced by the
various modifications to meet increasing difficulties.

Most of the Jurassic forms possessed shells well strength-
ened with ribs. These bands of support were of various
designs, suggestive of rings (Lytoceras), straps (Aspidoceras),
loops (Stephanoceras), and wavelets (Mgoceras). In not a
few cases the shell was further strengthened by the presence
of a keel, which must also have brought advantages in the
matter of stability (Cardioceras, Harpoceras, etc.).

EVOLUTION IN THE PAST

Many ammonites, nearer the end of their resources, were
crawling about in shells with dwarfed body-chambers (Cosmo-
ceras, etc.) ; whilst some forms were beginning to uncoil,
seeking salvation, it would seem, by a reversion to the more
or less straight shell of far-back ancestors (Scaphites, Ancylo-
ceras). This retrogressive movement became a prominent
feature with ammonites, when their decline had fairly set in.
In spite, however, of their trials and adversities, ammonites
made a grand display in Jurassic seas.
BELEMNITES Belemnites, meanwhile, although handicapped by being
the much-coveted food of many fishes and sea-reptiles, were
coming on with a flood tide. They continued for the most
part of small size ; but a few forms were now abroad fully a
yard in length (B. giganteus). Their ranks were certainly
presenting a less archaic character ; as some forms differed
but little from comjnon squids or calamaries (Loligo vulgaris).

NAUTILUS The old straight-shelled nautiloids had by this time been
wellnigh weeded out : and the group, which comprised
them, was represented almost entirely by forms more or less
identical with the living nautilus. Nautiluses, although
developed on more lasting lines than Ammonites, were never-
theless quite unimportant cephalopods in Jurassic seas.

Crustaceans, by readjustments in points of their structure
that had been more or less vetoed by Nature, were moving
SHRIMPS with the times. Well-developed shrimps and prawns were
numerous (Penceus, Mger) ; and small creatures, fairly

LOBSTERS describable as lobsters, were adding distinction to the crusted
fraternity (Eryon, Mecochirus, etc.). Animals of the same
family (Eryonidce) as some of these now wander in a sightless
condition in abysmal ocean depths.
CRABS Crabs, by a series of modifications from early shrimp life,
had now become distinguishable from their long-tailed fore-
runners. For the time being, however, they were insignificant,
alike in number and variety (Palceinachus, Prosopon).
BARNACLES Bamacles for the most part pursued an undemonstrative
career : but certain forms were setting their houses in order
by reducing their shell-plates, and arranging such as remained
in a more regular manner (Archceolepas).

Up to this Period fishes had been rapidly increasing in

Stephanoceras

JURASSIC PERIOD

[To face page 86

JURASSIC PERIOD

variety : but with the exception of sharks, skates, lung-
fishes, and forms resembUng bow-fins, and herrings, fish-Hfe
was not comparable with its present-day representatives. Nor
in the Jurassic can many comparisons be drawn. Of fish-Ufe
in very deep seas nothing, it may be mentioned, is known.
It is not unlikely, indeed, that as yet fishes lived only in
shallow and moderately deep waters.

Sharks flourished in old and new forms. In addition sharks
to those allied to Port Jackson sharks of our own time,
ancestors of " comb-toothed " sharks were now roaming
about (Notidanus) ; and sharp-toothed dog-fishes were also
in the seas (ScyliidcB). Angel-sharks, so caUed from their
large wing-like fins, had also appeared (Squatina) : and
certain sharks now possessed stout " backbones " rendered
flexible by a system of joints (PalcBospinax). Skates or rays
— first known in Carboniferous seas — were now well developed
(Rhinohatus, Belemnobatis) ; and Chimseras — foreshadowed in
Devonian times — were represented by various species.

This was rather a formidable array of fishes that, for the
most part, lived and fattened on their gentler brethren.
Still, many of the latter were doubtless swifter and more
agile swimmers than their foes. They had also, no doubt, an
additional — if unappreciated — preservative in being more
prolific.

The fringe-finned ganoids (Crossopterygii) still declined, ganoids
An old family, however, somewhat prominent in the Car- (cROSSOP-
boniferous, and consisting of fishes notable for internal terygians)
ossifications, and certain tail-reforms, kept up an imposing
appearance (CcElacanthidce, Undind).

The key to a highly developed and greatly varied fish- (actinop-
life had long been held by the flexibly finned ganoids terygians)
(Actinopterygii) ; and their ranks, therefore, excite the
keenest interest.

Some members of this Order, it must be admitted, re-
mained stationary in development. They stiU possessed
hard, bony scales, and had made little or no progress as
regards internal ossification. Their tails, moreover, con-
tinued of old type, terminating with the up-curved end of
the spinal column (Chondrosteus, Gyrosteus). Some descen-

EVOLUTION IN THE PAST

dants of these fishes never advanced to structure of higher
character ; and the gristly skeletoned sturgeon, with his
bony armour, and old-fashioned tail, may be regarded as
their living representative.

Flexibly finned ganoids with tails of modern type were
now far more numerous than their primitively tailed
brethren.

Prominent among these more accomplished swimmers were
some deep-bodied fishes {Dapedius), belonging to a family of
late Permian origin (Stylodontidce), and some of spindle shape
(Lepidotus), members of a family first known in the Trias
{SemionotidcB). But although modernism was evident in their
tail-structure, their bony scales were of remarkable thick-
ness, and their internal skeletons had undergone but little
ossification.

Other forms were thinner scaled, and well ossified inter-
nally (Caturus furcatus, etc.). Some of these were salmon-
shaped (Hypsocormus) ; others resembled the bony pike
{Aspidorhynchus). The most remarkable of all were sprat-
like forms with backbones completely ossified (Leptolepis
TELEOSTEANS sprattiformis). Ganoids — protected typically by hard and
enamelled bony scales, and possessing a more or less gristly
internal skeleton — had now definitely given rise to a new
group of fishes. True bony fishes, in short, were now in the
seas (Teleosteans).

VEGETATION Fine forests adorned the land, but, so far as is known,
the leafy wealth was much the same in character as that of
the Trias. Conifers, cycads, and ferns still held the field ;
and in some regions araucarias and allied forms attained
grand proportions. Cycads were extraordinarily abundant,
and extended over vast territories in all parts of the world.
Indeed at no future time were they so widespread, and so
varied in species — a starthng contrast with their present
circumscribed limits, and impoverished condition. " Horse-
tails " showed no sign of recovering their lost importance.
They certainly stood out here and there like giant forms of
old ; but for the most part they were of very humble propor-
tions. Their old associates the club-mosses appear to have
collapsed to the size of shrubs and bushes. And the pillar-

JURASSIC PERIOD

like sigillariae had wholly succumbed. In some regions gingko
or maidenhair trees — conifers with fern affinities — were in
a condition of great luxuriance ; but the cycads with
vesselled seeds (BennettitecB) continued, so far as is known,
the most highly organised forms in plant-life. Ferns also
were in great profusion, and those of newer type were greatly
extending their range (Leptosporangiates). Among these,
Male ferns (Aspidium), Bracken (P^ms) and Hart's Tongue
(Scolopendrium) had now appeared ; and the family to
which Royal Ferns belong — still retaining some special
features of ferns of the older type — attained its zenith
(Osmundacece).

Although it is not known that any angiosperms — the most
highly organised of plants now living — had as yet appeared,
it is highly probable that grasses and other simple growths
with " vesselled " seeds were amid the vegetation. It is
thought by many that angiosperms had for some time been
in course of development in far northerly regions, where
climate had not compelled migrations southward. Genial
conditions were certainly prevailing in this Period on lands
well within the arctic circle, for cycads were flourishing in
Spitzbergen. The far north, therefore, may well have had
some surprises in store.

Insects — especially wood-eating beetles — were abundant, insects
May-flies of many species flitted about ; and dragon-flies,
more or less developed in Carboniferous times, had now
become differentiated into a distinct family (Odonata).
There were also many kinds of insects unknown in earlier
times — mosquitoes (CulicidcB), gnats (Chironomidce), ants
(FormicidcB), crickets (Gryllus), earwigs (Baseopsis), and
termites (TermitidcB). The busy bee was also now abroad
{Apiarid).

About the marshes, lakes, and rivers no amphibians of amphibians
giant size were now to be seen ; and this class of life seems
to have been represented only by small newts and salamanders
of primitive type (HylcBobatrachus). Amphibians, owing to
the wonderful developments of reptile-life, were now to play
a quite insignificant role in Nature's economy.

Reptiles rose to their zenith ; and their power was pro- reptiles

EVOLUTION IN THE PAST

claimed not only on land and sea, but also in the air. " Creep-
ing " is indeed quite an inadequate appellation for the
fraternity in Jurassic, and even in earlier times.

Dinosaurs were now the leaders. Vegetarian as well as
flesh-eating forms were extraordinarily abundant ; and they
presented the most extravagant and grotesque display of
life that has ever existed on earth.

In both hemispheres they were in their glory ; but evidence
points to the western parts of the North American continent
as the scene of their grandest and wildest development.
Here gigantic brutes were roaming, in the presence of which
the largest elephant would have cut a poor figure. Take,
for instance, the Diplodocus family, so named from certain
branched or " double-beam " bones which its members
possessed on the under-part of the tail. Some of these
creatures were over eighty feet in length, and could raise
their heads some thirty-five feet above the ground. They
seem to have possessed little or no armour : but the tail was
doubtless serviceable for dealing blows. The position of the
nostrils — high up the head — points to aquatic habits ; and
the animals, no do\ibt, subsisted mainly on the bed-herbage
of lakes and rivers. In such haunts, the long neck would be
of great service, enabling the animal to stand and browse,
even in moderately deep water ; and, when disposed, to bring
its head above the surface. It, moreover, carried up the
head as a watch-tower, and foes necessitated vigilance. The
feet were fairly well adapted for land-locomotion ; but their
construction is suggestive of a sprawUng gait. The animals
must have had to exercise great caution in swampy districts :
for if by chance they strayed into miry ground, there they
must have remained.

No remains of the Diplodocus family have been found out-
side the western area of the United States. Other very big
herbivorous dinosaurs were also living in those regions
{AtlantosauridcB). Many of these measured sixty feet from
snout to tail-end (Brontosaunis) ; whilst a few forms were
twice that length (Atlantosaurus). Remains of some animals
belonging to this family have been found in England near
Peterborough (Cetiosaurus Leedsi). In order to keep them-

DIPLODOCUS CARNEGIEI

[To face page 90 (tl

JURASSIC PERIOD

selves in condition, these enormous vegetarians must have
spent the greater part of their lives in eating.

Whilst some dinosaurs were chiefly remarkable for their
colossal proportions, others were signalised rather by their
grotesque appearance. Look at Stegosaurus, for instance,
with his pikes and battlements. His dorsal castellation, no
doubt, denied him the luxury of rolling on his back ; but it
kept him well guarded against assault in that quarter. A
number of Httle bones well shielded his throat ; whilst his
flanks, though somewhat exposed, could doubtless be covered
by a sweep of the spiky tail. The mere sight of such animals,
standing in some cases eleven feet at the highest point of their
fortifications, must have inspired some terror. They certainly
required elaborate protection, for they were bulky, heavy-
limbed, and incapable of speedy flight. Nor were they like
Diplodocus, capable of taking a wide survey, and catching
early sight of danger. As they were vegetarians in diet, they
were probably, in spite of grim aspect, peacefully enough
disposed when unmolested.

Their intelligence must have been very limited ; for their
brains were excessively small, even for dinosaurs. Curiously
enough a mass of nervous tissue — the result probably of a
block caused by the smallness of the brain chamber — was
lodged in the region of the haunches. It has been suggested
that this second accumulation was in the nature of a supple-
mentary brain — that it formed, in short, a second seat of
intelligence. No doubt the " upper chamber " was of
extraordinarily mean capacity ; and, in the interests of
good government, some check on its prerogatives may have
been desirable ; but there is really no reason to suppose that
the " lower chamber " contained any intelligence at all.

The Stegosaurus genus was confined to North America ;
but remains of distantly allied forms have been found in
England (Scelidosaurus). These animals were capable of pro-
gression, in a somewhat laboured style, without requisitioning
the " arms " ; and the tail no doubt served as a useful
appendage on which to take short rests. They possessed
well-developed shoulder-spikes ; but they were not so elabor-
ately armed as Stegosaurs.

EVOLUTION IN THE PAST

Herbivorous dinosaurs, footed like birds, were also in
existence (Camptosaurus). These, like the Triassic carnivor-
ous forms, were very short in the " arms," and effected
locomotion in kangaroo fashion. They were models of
activity in comparison with Diplodocus and Stegosaurus ;
and as they were not provided with armour, they probably
took to flight, when threatened with serious danger.

Herbivorous dinosaurs must have had to keep a cautious
look-out against their carnivorous relations, lurking in large
numbers among the cycads and gingko trees. Ceratosaurus
may be taken as a type of the flesh-eating dinosaurs. This
animal stood some eight feet in height, and progressed, like
some of the herbivorous forms, in bipedal fashion. His head
was large for a dinosaur ; and he was doubtless better brained
than his victims. He had, moreover, a weapon in the form
of a horn on his snout. His greater brain power, nasal
implement, and greater ability to move quickly from place
to place, must have given him great advantages over such a
creature as Stegosaurus. No wonder the latter required
strong armour, if he was to keep a place in creation. Megalo-
saurus was an allied carnivorous form with powerful jaws
furnished with saw-like teeth. It has only quite recently
become known that this animal possessed, like Ceratosaurus,
a horn on the snout.

Remains of an interesting dinosaur of small dimensions
have been found in central Europe (Compsognathus). This
creature was in existence in late Jurassic times ; and was
similar in shape to Ceratosaurus. Her height — the remains
are probably those of a female — was about two feet when
standing erect ; and to judge by her hollow limb-bones and
vertebrae, she was possessed of considerable agility. Birds
were making their appearance at this time ; and she and her
like were probably in the habit of chasing these incipient
aeronauts. Indeed by eliminating the feebler flyers, they
may have expedited the evolution of more powerfully winged
birds.

It is a question if any of the dinosaurs brought forth
their young alive. It certainly detracts from the dignity
of the huge dinosaurs to suppose that they were layers of

JURASSIC PERIOD

eggs. But it is very likely they were ; for such dull-witted
monsters can hardly have been equal to the parental duties
entailed by the viviparous system. If any dinosaurs brought
forth their young alive, such were to be found most probably
among the small forms. There is indeed some, though not
conclusive evidence that Compsognathus was a viviparous
creature.

Although now quite thrown into the shade by the
later developments of reptile-life, semi-lizard creatures of
Sphenodon type abounded. And there is some evidence
that true lizards were in existence before the close of the lizards
Period (Macellodus). The evidence is not undoubted ; but
it is highly probable that some primitive forms of those
creatures had by this time emerged from the Sphenodon
ranks.

Crocodiles had now assumed a definite character, having crocodiles
more or less lost the features which held their Triassic fore-
runners in close connection with dinosaurs, and lizard-like
animals (TeleosauridcB). They all seem, for the greater part
of the Period, to have been creatures with long and slender
snouts ; and they no doubt closely resembled the gavials
of our own time. They differed, however, from all croco-
diles now living in some important respects. The backbone-
vertebrae were of primitive type, being concave at both ends.
In the case of living crocodiles the vertebrae are convex-
concave, fitting into each other like ball and socket ; and
the backbone, therefore, has a firmer and more powerful
articulation. There was also greater disparity in the relative
lengths of the fore and hind limbs than is the case with
crocodiles now living. The hind-limbs were comparatively
long, and must have been in great requisition for swimming ;
whereas with living crocodiles the hind-limbs are shortened,
and swimming is effected almost entirely by movements of
the tail. These old forms, moreover, differed from living
crocodiles in not having their breathing passages so arranged
that the mouth could be kept wide open under water without
inconvenience. Hence, if seizing prey in their jaws, they
endeavoured to submerge and drown it, they ran the risk of
drowning themselves at the same time. There is some

EVOLUTION IN THE PAST

evidence that a structural modification to ensure them
against this risk was in progress ; but it is not until the next
Period that it is found in working order.

Jurassic crocodiles, although mostly of marine habits,
did not, as a rule, venture far out to sea. Some of them, how-
ever, were to a certain extent sea-rovers, and had developed
fish-like features (Metriorhynchus, Geosaurus). The Umbs of
these more venturesome animals had become modified into
paddles. The fore-limbs, moreover, had been considerably
reduced, and exhibited likeness to the pectoral fins of fishes.
The hind-limbs had undergone less transformation, and were
of good length, and retained a fair amount of scrambling
ability. The animals no doubt enjoyed visiting the shore for
a bask in the sun, and periodical visits would be necessary
for the females for egg-laying purposes.

Towards the close of the Period some small crocodiles
with broad and comparatively short snouts, and resembUng
the common crocodiles of to-day, made their appearance
{Atoposaurus , Goniopholis). In some of these creatures the
disparity between the fore and hind limbs was not so marked
as in the case of their long-snouted relations. These short-
snouted forms, it is supposed, haunted lakes and rivers, and
waylaid little mammals coming down to drink.

Crocodiles with backbones vertebrated in the modem
manner, with a ball-and-socket arrangement, were possibly
appearing at this time ; but the evidence is not conclusive
{Heterosuchus).

CHELONIANS Tortoises had now become very numerous ; and various
species of " hidden-necked " (Cryptodira), " side-necked "
(Pleurodira), and intermediate forms were to be seen in the
lakes and rivers.

There is no evidence that any tortoises had taken to
living permanently on land. On the other hand some of them
seem to have been occasionally issuing from the rivers and
estuaries, and embarking on sea life — setting out in short
to found sea-tortoise or turtle communities (Thalassemy-
didcB). This enterprise, however, was only in a preliminary
stage in this Period.

Long-necked plesiosaurs were now to be seen of much

JURASSIC PERIOD

larger size — some attaining a length of fifteen feet (Crypto- plesio-
clidus). The limbs had become completely adapted to saurians
swimming purposes, and a tail-fin — at least in some cases —
had been developed (P. macrocephalus). Some new forms,
characterised by comparatively short necks, were also in the
waters (Pliosaurus). These were formidable-looking brutes,
attaining in some cases a length of thirty feet, and their
teeth — long and sharp — no doubt occasionally met in the
flesh of plesiosaurs.

Ichthyosaurs or " fish-lizards " were now to be seen forty ichthyo-
feet in length, and with Umbs of more complete paddle-con- saurians
struction. Instead of coming to shore for egg-laying purposes,
as probably did the earhest ichthyosaurs, the females brought
forth their young alive out at sea : and it is doubtful if ichthyo-
saurs ever visited the land in Jurassic times.

Reptile-Ufe had not exhausted its powers in the evolution
of swimming, creeping, leaping, and walking forms : for
creatures capable of rising from the ground, and navigating
the air, had now emerged from the ranks.

These somewhat bird-Hke forms are variously known as flying
" flying hzards," " wing-fingered " animals, and " dragons lizards
of the air " (Pterosaurs, Pterodactyls). According to the
geological record they made a sudden appearance : but such
of course cannot really have been the case. The modification
of fore-limbs into organs for holding up folds of skin, and the
ultimate adaptation to aerial flight — accompanied as it must
have been by various bodily modifications — represented a long
process : and there is no doubt that the known Jurassic
forms were preceded by many small and imperfectly winged
creatures, of which no trace has yet been found. From what
particular group of reptiles they were derived is quite un-
known.

The wing of a flying lizard in being of a membranous
substance was hke that of a bat ; but its framework was
different. It was supported by the " arm " and a greatly
elongated " little " finger. The thumb had practically dis-
appeared ; but the first three fingers remained, and were free
and usable as claws. A bat's wing, on the other hand, is sup-
ported by four fingers, and the thumb is the only free digit.

EVOLUTION IN THE PAST

Jurassic flying lizards were furnished with teeth ; and they
subsisted, no doubt, chiefly on fish ; but dragon-flies and other
large insects were not despised. The animals varied in size ;
some being no bigger than sparrows (P. spectahilis) ; whilst
others were as large as rooks (Rhamphorhynchus, P. crassi-
rostris), and herons (Dimorphodon). Some species possessed
long tails, designed, it may be supposed, chiefly for steering
purposes (Rhamphorhynchus). The long tail, it would seem,
proved inconvenient, for apparently no forms in the next
Period possessed the apparatus.

Towards the close of the Jurassic more important invaders
of the air were in existence than flying lizards ; for there
is no doubt that on the site of Europe birds were then in
being. They differed in some important respects from
modern birds ; but they were well- developed creatures.
There is, therefore, no doubt that although they are the
first known birds, they must have been preceded by many
other forms. Their descent is lost in obscurity. They may
have come down from some small Triassic Dinosaurs ; or
there may at one time have been a common stock from which
birds and dinosaurs emerged.

The remains found consist of a few skeletons, and im-
pressions of feathers ; and all belong to one genus (Archcsop-
teryx). In body these creatures were about the size of
crows. The wing was small, but did not greatly differ from
that of a living bird. The thumb, however, was developed
as a claw ; and the two surviving fingers, although support-
ing some of the flight feathers, were not joined together as
with modern birds ; and were, moreover, armed with claws.
The bony tail — longer than the body — was a most remarkable
feature. It consisted of twenty joints, each of which
supported a pair of feathers. It was, in fact, a reptile's tail,
decorated with feathers : and very different, of course, from
the bony stump, and fan-like arranged plumage which
constitute the tail of present-day birds. These strange
creatures were also remarkable in possessing teeth — another
feature connecting them with reptiles. The body was not
lightened, as with modern birds, by a framework of hollow
bones, and this fact, taken in connection with the small size

FLYING LIZARDS
Remains found in Jurassic strata of Bavaria

[To face pu%c 96 (i)

ARCH^OPTERYX
Remains found in Jurassic strata of Bavaria

[To face page 96 (11)

JURASSIC PERIOD 97

of the wing, and its deficiency of strength owing to the non-
junction of the fingers, leads one to suppose that these birds
were not expert flyers. They, no doubt, indulged in occa-
sional flights of short duration ; but they probably scrambled
up to perching-places on the trees by the aid chiefly of their
legs and wing-claws. They must have been much persecuted
by reptiles ; for all new modes of life are sure to meet with
violent opposition from the " authorities " of the time.

Mammals had now been long in existence ; and doubtless mammals
had greatly increased in number ; but they do not seem to
have been much larger than their mouse- and rat-sized
ancestors. Some, to judge by their teeth, were primitive
insectivores, and may have been forerunners of moles (Amphi-
therium). Some forms probably did not differ very much
from living opossums (Phascolotherium) ; whilst others were
apparently developing in the direction of squirrels and other
rodents (Plagiaulax, Bolodon, etc.).

Some of the creatures had teeth far exceeding in number
those of any living mammals ; but in no case do the teeth
indicate carnivorous habits.

Primitive mammals, therefore, were still in an age of
innocence. But times were difficult ; and they probably
dwelt for the most part in holes and corners, and on high
tree-branches ; and rarely ventured from their retreats save
under cover of darkness.

MESOZOIC AGE

CRETACEOUS PERIOD

DINOSAURS The reptile boom was now subsiding. Dinosaurs, it is true,
continued fairly prosperous for some time. They had,
however, passed their zenith, and soon after the early part
of the Period their decline was somewhat rapid. Many
changes were going on in the world ; and the animals had
become too slow in adaptation. They appear to have found
some relief from high pressure by migrations. Not only in
North America and Europe were they now living, but some
had found their way to South America and India. And on
eastern lands in Africa, just south of the equator, some huge
forms were sprawling about with limb-bones twice the size of
those of the great Diplodocus.

Among the vegetarians, none of the Diplodocus family
were now to be seen ; and only a few comparatively small
forms represented the Atlantosauridce — famous, in Jurassic
times, for creatures of extensive dimensions. Stegosaurus
had left no descendants : but Polacanthus was no unworthy
representative of the type. This animal — standing between
three and four feet in height — had the anterior half of its
back protected by a double row of erect plates in Stego-
saurian style. The rest of the dorsal armour consisted of a
large shield. The tail bore ten pairs of bony spikes similar to
those of the Jurassic monster.

Other remarkable dinosaurs, flourishing in the early
Cretaceous, are known as Iguanodonts, as their teeth re-
sembled those of the Iguana lizard. Remains of the animals
have been found in England, Belgium, and Germany. They
were big bird-footed creatures, standing in some cases fifteen
feet in height. In general appearance these veritable Gogs

IGUANODONTS
Remains found in England and Belgium

[To face page gS (i)

CRETACEOUS PERIOD

and Magogs resembled the bipedal dinosaurs of the last
Period. The males were peculiar in having the thumb
modified into a spur or spike, rigidly fixed at right angles to
the palm of the hand. The thumb, in fact, had become a
weapon, capable of inflicting severe wounds. It represented,
no doubt, a retaliatory movement. Herbivorous dinosaurs
had long been obhged to seek safety from carnivorous foes
in flight, or by passive resistance under cover of heavy
armour. Some of them at least were now capable of other
tactics.

Big herbivorous dinosaurs, related to iguanodonts, were
living in North America (Claoscurus). These animals, how-
ever, were practically thumbless. Their tails were remarkably
thick and powerful. This stout appendage made with the
hind-limbs a sort of three-legged stool ; and the animals
could feed off their favourite trees, comfortably seated. They
were able to obtain much better food than hard cycads and
conifers, as will be noted presently.

Carnivorous dinosaurs were well represented in the early
Cretaceous by descendants of horn-snouted Megalosaurus of
Jurassic fame. Later in the Period several allied forms were
in existence. Some of these were remarkably light and agile,
and must have caused the bulky vegetarians considerable
discomfort (Lcelaps).

On the North American continent reptile-life, in later
Cretaceous times, was signalized by the appearance of some
wonderful herbivorous dinosaurs. And, as after events
proved, this was a last and supreme effort of the " terrible
lizards " to keep a foothold on earth.

The most notable of these heroic brutes has been named
Triceratops — " the three-horned." This quadrupedal creature
had an enormous head, but very little in it in the form of
brains. The bone of the skull did not stop at the ordinary
limit, but — as a counterpoise to the frontal heaviness — was
continued over the neck in a manner suggestive of an
Elizabethan collar. There was, however, nothing else
Elizabethan about this quaint monster. Two sharp,
good-sized horns stuck out from his forehead, and a
small horn surmounted the snout. He was therefore well

100

EVOLUTION IN THE PAST

equipped for frontal attacks ; but as his capacious body was
not protected with armour, he must have had to rely on his
tail to deal with sudden flank assaults. His horns were
doubtless of use for other purposes than fighting. If he had,
like elephants, a partiality for roots, he could use them for
digging up shrubs and trees. It is not likely that these
appendages underwent any improvement as the result of
what is called sexual selection. It would certainly be rash
to suppose that these cold-blooded, dull-witted creatures
exhibited much ardour or discrimination in their love
affairs.

Other dinosaurs also brought a lustre to the waning line.
These were remarkable for possessing duck-like bills, fitted
out with an immense number of teeth — in some cases two
thousand (Hadrosaurus). The dentition seems to have been
designed purely for feeding purposes ; at least it was iU-
adapted for hostilities. The animals had little or no armour ;
and unless they could trip up a foe, and roU over him, they
must have fared ill in a quarrel. Possibly their lines for the
most part were in out-of-the-way places, where they could
feed on the herbage of lakes and streams in peace and comfort.
Some portly creatures attained a length from snout to tail-end
of nearly forty feet.

Whilst dinosaurs were all on side-paths leading to extinc-
tion, less lugubrious was the outlook of the crocodiles.
Indications had been made in the last Period that these
reptiles were to receive some structural benefits. The im-
provements were directed to increasing the flexibihty of the
backbone ; and to so altering the breathing arrangements as
to enable the animal to drown its prey without drowning
itself. In early Cretaceous times many old-fashioned forms
were still in existence (Pholidosaurus , Goniopholis) ; but
later in the Period the improvements apparently were
possessed by a vast majority of the crocodiles (Thoracosaums,.
Holops).

The vertebrae of the backbone worked more freely, as
they were of concave-convex pattern, fitting each other Uke
ball and socket. The new breathing arrangement was still
more remarkable. Under the old system the nasal passages

CRETACEOUS PERIOD

lOI

communicated with the windpipe, by running through the
bony palate into the mouth ; and to keep the mouth open
under water would have been suicidal. To achieve the object
in view, the anatomy had been considerably modified. The
nasal passages had been carried further back ; and could,
with the windpipe, be shut off from the mouth by means of
valves at the back of the tongue. A want long felt by croco-
diles— enablement to drown prey without risk of self-drown-
ing— had, therefore, been supplied.

Alhgators seem to have been in existence at this time alligators
(Bottosaurus). These creatures were probably an offshoot
of the crocodiles. Indeed, excepting for the manner in
which some of the lower teeth bite into the upper jaw,
alligators are practically identical with short-snouted croco-
diles.

The sea-roving crocodiles {M etriorhynchus) of the last sea-roving
Period were no longer represented. Possibly they never crocodiles
became sufficiently expert swimmers for the manner of life
they had adopted.

In some parts of Europe, however, reptiles of a different dolicho-
type had betaken themselves more or less to a watery life, saurs
These were probably modified descendants of some of the
semi-lizard creatures of Triassic times. In some respects they
were developing in the direction of snakes. These dolicho-
saurs, or " long lizards " as they are called, did not, in early
Cretaceous times, exceed a yard in length ; but in the
course of the Period, forms of twice and even thrice that
length were in the waters (Dolichosaurus). They never
became so far modified in their limbs as to become completely
adapted to aquatic life.

In late Cretaceous times some thorough sea-going reptiles mosasaurs
• — probably an offshoot of the " long lizards " — were abroad.
These creatures have been named Mosasaurs, as remains of
them were first found in the valley of the Meuse, or Mosa.
Subsequent discoveries have shown that they were by no
means confined to that region ; but that they lived also in
seas of North and South America, and extended their range as
far as New Zealand. They possessed skulls lizard-like in
shape, and long, snake-like bodies. Their limbs had become

102

EVOLUTION IN THE PAST

thoroughly adapted to marine Hfe, being provided with
powerful paddles. They further resembled snakes as regards
the mouth. This organ was capable of considerable dis-
tension, as the head bones worked freely upon one another,
and the two halves of the lower jaw, joined by elastic liga-
ment, could be drawn well apart. The throat, no doubt, was
also as with snakes capable of considerable expansion, and the
animals were enabled to seize and swallow prey of large size.
They possessed also snake-like teeth, pointed and curved
backwards. Such teeth were, of course, useless for mastica-
tion, but they effectively prevented prey once seized from
wriggling out of the mouth. As, however, the mosasaurs
were also provided with masticating teeth, it is not likely
that their manner of feeding was entirely snake-like. They
attained in some instances to a length of fifty feet ; and ably
supphed the vacancy caused by the early collapse of other
sea-going reptiles.

Some distantly related forms managed to hold their own
for a time in the next Period (Champ sosaurus) ; but doUcho-
saurs, and mosasaurs, strictly so called, all disappeared in
the great reptile " slump " which set in at the close of the
Cretaceous.

CHELONIANS Tortoises meanwhile had undergone but little change.

But however stolid and conservative they may have been as
a rule, a spirit of enterprise was in their ranks. A tendency,
shown by some river-haunting forms in Jurassic times, to
take to marine life had become strengthened in the course of
years ; and in late Cretaceous times sea-tortoises or — to
speak more correctly — turtles, with limbs modified into
true paddles, abounded in some of the shallow seas. Some
of these animals seem to have been closely allied to " edible,"
some to " loggerhead " turtles (Allopleuron, Lytoloma) of our
time.

Other chelonians had become more partial to mother
earth, and buried themselves in mud more or less completely
(Trionyx).

ICHTHYO- Whilst turtles were beginning to swell the ranks of marine
SAURIANS life, the whale-shaped ichthyosaurs or fish-Uzards were
getting into a parlous condition. They had now lost their

CRETACEOUS PERIOD

103

teeth — possibly as a result of racial old age. How far this
deprivation affected their fortunes cannot be determined.
Whatever the cause, they became practically extinct long
before the close of the Period. Their career had probably
been mainly in the shallows, where the competition of
younger life may in time have become too keen. As a forlorn
hope they may have migrated to deep waters, and in their
new sphere have been starved and persecuted out of exist-
ence.

Plesiosaurs were also under great pressure ; but their plesio-
coUapse came later than that of the fish-lizards. The short- saurians
necked, sharp-toothed forms of Jurassic times had apparently
left no descendants (Pliosaurus) ; but plesiosaurs resembling
them at least as regards the teeth were in Cretaceous waters
(Polyptychodon). For a considerable time the long-necked
forms flourished greatly, and in many parts of the world ;
but they were submitted to severe tests in the latter part of
the Period. Even then, however, some forms with " record "
necks were to be seen. Elasmosaurus, for instance, had a
neck twenty-two feet in length. Many curiously modified
forms were also then in evidence. Some of these had long
heads, obtained apparently at the cost of the neck (Trina-
cromerum). In some animals the head exceeded the neck
in length (Dolichorhynchus). These modifications were, no
doubt, desperate attempts to meet changing conditions ; but
they proved of no permanent avail. Indeed they were prob-
ably reversions to a form of structure such as their far-back
unknown land-ancestors had possessed ; and manifestations
of atavism are not indicative of true energy. But however
that may have been, plesiosaurs, long-headed and short-
headed, and with necks of whatever length, were one and all
doomed. They were essentially creatures of old-fashioned
type, and without sufficient elasticity to be effectively trans-
formed. Difficulty in obtaining food, owing to the greater
wariness, keener sight, and better swimming powers developed
in fishes, may have been one of the causes which brought
about their downfall. As also may have been the increase of
large voracious fishes. But the closing portion of the Creta-
ceous is one of the darkest epochs in Geology ; and the

104

EVOLUTION IN THE PAST

precise conditions under which various forms of hfe then
disappeared cannot be ascertained.
FLYING Flying Hzards were also doomed ; but they showed
LIZARDS considerable vitality for a long time. Those of the Jurassic
were mostly of small size, but in this Period enormous
creatures were navigating the air. Take Pteranodon, for
instance. Here was an animal with an expanse of wing of
eighteen feet ; and other forms were about with even greater
wing-spread. This development had necessitated an excise,
which no doubt had been levied on the legs ; for these had
become much enfeebled. But however undignified these
creatures may have appeared as they shuffled along on land,
they must have been grand and graceful objects when sailing
in the air.

The winged lizards of earlier times were more or less
provided with teeth ; but Pteranodon, and many other
Cretaceous forms — especially on North American scenes —
were toothless. In this they exhibited a change going on in
bird-life. But in their case this breaking away from reptile
traditions was of no good augury. Indeed it must be
regarded as symptomatic of senility and decay in the no
longer youthful Order.

Notice must now be taken of fishes, which, in addition
to numberless commotions and cannibalities amongst them-
selves, were victimised by various sea-roving birds and
reptiles. But internal dissensions and havoc from without
had served in the past to bring out their wonderful adapta-
biUties ; and a brisk progress continued.
SHARKS Although sharks had undergone some modifications result-
ing in the evolution of new forms — some specialised as
Porbeagle sharks had now appeared — they were destined to
remain in a primitive condition of development. The
vertebral column continued of gristly substance, and still
extended to the extremity of the tail. These features,
indeed, have continued until the present day.

The most notable event in the Cretaceous annals of sharks
and closely allied forms was the appearance of saw-fishes
{Pristiophorus, Sclerorhynchus) ; but the rostrum-teeth, as
might be supposed, were not of so trenchant a character

FTERANODON

From Cretaceous strata of Western Kansas, U.S.A.

[To face page 104

CRETACEOUS PERIOD

105

as in later forms. Other members of the group were de-
veloping in the direction of eagle-rays, or " devil " fishes
(Ptychodus).

Dipnoans or fishes of the lung-breathing type had retired dipnoans
from the seas to take up permanent quarters in fresh waters ;
and no great future was in store for them.

Among the fringe-finned ganoids (Crossopterygii), one ganoids
family — very little changed from Devonian times — con- (crossop-
tinued in some force for the greater part of the Period, and terygians)
then dwindled to extinction (Ccelacanthidce). Other forms
remained ; but fishes of this Order were not destined to
take much part in the finny life of the future ; and it will
not be necessary to refer to them in subsequent Periods.
Their decline continued in after times ; but they have
struggled on, and are represented to-day by one small
family, whose members are found in a few rivers of Africa
(Polypteridce).

The flexibly finned ganoids (Actinopterygii) had been (actinop-
exhibiting advances in development ever since Devonian terygians)
times, and had become well established in a variety of forms
in the Jurassic. Towards the close of that Period a small
number of them had attained the condition of being true
bony fishes ; and were, indeed, the immediate heralds of a
great revolution.

During early Cretaceous times steady progress was no
doubt made ; but there is not much direct evidence as to
this. It is clear, however, that when the Period was well
advanced, bony fishes gained a decided predominance over
the ganoids that had not attained the higher anatomical
standard. Ganoids thus became reduced to the long-decadent
fringe-finned forms, the flexibly finned fishes more or less
resembling sturgeons, and bow-fins, and a few other types
not closely comparable with living fishes.

Among the bony fishes shoals of herring of various species teleosteans
were in evidence (Pseudoberyx, Histiothrissa, etc.). Some
large related forms with stout pointed teeth were also in
the seas, living probably at the expense of their small rela-
tions (Poriheus, Saurodon). These formidable fishes attained
in some cases a length of six feet ; and somewhat resembled

io6

EVOLUTION IN THE PAST

the voracious dorabs of our own time (Chirocentrus). There
were also many spiny-finned fishes. These evidently had
an excessive supply of bony substance, and the surplus
was finding its way along the fins. The most numerous of
the company were closely related to the Beryx of our own
time (Hoplopteryx). Others seem to have developed more or
less into horse-mackerel (Aipidhys), sea-perches (JProlates),
and sea-bream (Pagellus).

Fishes with the pelvic fins brought forward, and greatly
enlarged as if for flying purposes, were also to be seen
(Chirothrix). Fishes eel-shaped — and therefore degenerate
— were numerous (Echidnocephalus, Derceiis, etc.) ; and
true eels were in existence (Urenchelys). Here also were
fishes of the family to which tarpons belong (Elopidce) ; and
many other forms were abroad, belonging to families which
exist to-day {Albulidce, Halosauridce, ScopelidcB, etc.).

In addition to these, there were various bony fishes,
divers in form, and of uncertain affinities (Ctenothrissa, etc.).
Indeed in late Cretaceous times there was a decided boom
in the fish world, resulting from the new anatomy. An
analogous outburst of activity may be witnessed on a small
scale in human affairs, consequent on some great discovery or
invention.

Notice must now be taken of the lower classes of the
marine population,

CRUSTACEANS Many crustaceans in Jurassic times had become recognis-
able as shrimps, prawns, and lobsters. In the Cretaceous
Period all these differentiated creatures became more dis-
tinctly defined, and of greater variety. New forms of prawns
(Hoplophorus, etc.) and various small lobsters (Enoploclytia,
Clytia Leachii, etc.) were now in being. Among the latter
some essentially resembled the Norway lobster of our own
time (Nephrops) : other allied forms were probably in-
distinguishable from the modern Crawfish (Palinurus). There
were also numbers of lobsters that had taken to embedding
themselves in mud (Callianassa).

But it was in crab-Ufe that the greatest developments
were in progress. Crabs, although foreshadowed in far-back
times, cannot be said to have expressed themselves un-

CRETACEOUS PERIOD

107

mistakably before the Jurassic. Once established they seem
to have advanced rapidly ; and they were present in Creta-
ceous seas with carapaces variously shaped. Some of the
creatures apparently were very similar to the modern sponge-
crabs ; and possessed special limbs for holding a sponge or
other marine organism on the back for self-concealment
(Dromiopsis). Other forms seem to have closely resembled
the shore-crabs, masked-crabs, and frog-crabs of our own
time (Necrocarcinus, PalcBocorystes, Raniella).

Some barnacles were now to be seen directly fixed to their
haunts by means of cement, the stalk apparently having
gone to waste (yerruca). This method of attachment no
doubt saved the animals some exertion ; and life in barnacle
circles became more inert than ever.

Whilst crustaceans were thus advancing, hard times had ammonites
set in for most of the cephalopods. The ammonites, it will
be remembered, had a large measure of prosperity in the
Jurassic Period ; but clear signs were not then wanting of
impending trouble. Matters became far more serious in the
Cretaceous ; and the resources of these enterprising molluscs
were tried to the uttermost. Surely no creatures ever battled
more strenuously with adversity. Some appear to have
wooed Fortune with elaborate ornamentations of the shell
(Hoplites, Douvilleiceras). Many ceased indeed to be ammon-
ites in the sense of creatures with shells suggestive of a ram's
horn. Some forms had their shells twisted into little towers
(Turrilites). Others were more or less uncoiling themselves
— reversing engines, as it were, in view of dangers ahead
{Hamites, etc.). Some indeed had become completely uncoiled
(Baculites). But whatever their adaptations, ammonites con-
tinued to decline ; and in the next Period this once great
Order was represented by a mere remnant of moribund
forms.

The squid-like Belemnites well maintained their position belemnites
for a time ; and many new forms made their appearance.
Curiously enough when their arch-enemies, the Ichthyosaurs,
were in extremis, they themselves commenced to decline.
Gradually dwindling down to a few genera, they became at
the close of the Period wellnigh extinct.

io8 EVOLUTION IN THE PAST

OCTOPI The decline of the belemnites may have been in part
caused by the rise of allied and more active creatures, known
as octopuses. These voracious molluscs — now appearing —
had hardly any shelly substance to carry. A handicap to
elasticity of movement — inherited from remote sluggish
ancestors — had, therefore, been practically removed (Palce-
octopus).

NAUTILI The decay in ammonite and belemnite ranks was in part
counterbalanced by the success of cephalopods of more
ancient lineage. Some exceptionally large forms of nautiluses
now made their appearance. The old blood was reasserting
itself.

UNIVALVED Marine gastropods or sea-snails do not seem to have been
MOLLUSCS much affected by the changes going on around. Those with
the improved breathing apparatus, initiated in the Trias,
and largely in evidence in the Jurassic, were greatly on the
increase. But old-fashioned siphonless forms that carried
on respiration simply through the skin, or by means of gills
and slightly modified mantle-edges, were probably still in a
large majority.

BIVALVED Bivalved molluscs had at no time proved unequal to the
MOLLUSCS struggles of life ; nor did the Cretaceous Period find them
otherwise.

There is nothing notable to report about the mussels,
scallops, cockles, and oysters ; except that among the last
were some exceptionally large forms. Several present-day
families of bivalves with burrowing habits first become known
in this Period {Mactridce, SaxicavidcB, etc.). Other bivalves
were following out experiments made in the Jurassic ; and
they met with temporary success. The animals appear to
have been related to clams ; but they were very unlike clams
now living. Their shells had assumed a horn-like shape ;
and some rather later forms resided in long, funnel-shaped
shells, protected at the top by a lid (Hippurites). These well-
accommodated animals became very numerous and widely
distributed. But the ostentatious shelly residence was not
really significant of great wealth within. The creatures
certainly kept up appearances for a long time ; but to-
wards the close of the Cretaceous they failed to meet the

Fishes
(Clenotli
rissal

Ammonites
(Turrilites)

(Hoplite)

Enoplo-
clytia

Sea-urchin
(Salenia)

HiKpurites

Siphonia

Coscino-
pora

Ammonites
(Hamile)

(Hoplite)

Clytia
I-eachii

Baculite

CRETACEOUS PERIOD

[To /ace page io8

CRETACEOUS PERIOD

109

demands of Evolution, and were struck off the moUuscan
roU.

The most remarkable feature in the Cretaceous annals lampshells
of brachiopods, or lampshells, was the great prosperity
attending an old family, which had in Ordovician times
dissented from other brachiopods. The dissent consisted in
discarding the stalk, and developing a cement as means of
fixation (Craniidce). This persevering nonconformist family
is still living. Two other old families — notable for beaked
shells — that had taken a new lease of life in the Trias,
were also much to the fore in the Cretaceous Period (Tere-
hratulidcB, Rhynchonellidce).

Among polyzoans, the older-developed colonies, with polyzoans
zooids in open-mouthed tubes (Cyclostomata), were for a
great part of the Period keeping well ahead of the " lid-
mouthed " colonies (Cheilostomata). In late Cretaceous
times, the latter seem to have drawn abreast of their rivals.
The reformed colonies, flushed with success, were in some
cases effecting changes in their social system. Certain zooids
were losing their status by being modified into organs
(avicularia) for keeping off intruders, and for seizing food
for their fellow-colonists (Cellaria, Onychocella). Zooids in
close proximity to these transformed individuals must have
lived in great ease and luxury. A privileged class, in short,
had risen in the community. Another change was in pro-
gress in some colonies. Certain zooids were being transformed
into menial appendages (vihracula) for bringing a colony to
anchor (Lunulites).

Sea-urchins continued dominant among the spiny-skinned sea-urchins.
creatures, and underwent great developments as the Period
advanced. Old forms of more or less sedentary habits, with
circular tests, were very numerous ; and new forms of these
were making their appearance (Salenia). But it was among
the more inquisitive urchins, that had, by burrowing or more
active locomotion, lost their circularity, that a notable
increase was taking place. Heart-shaped forms — sometimes
termed heart-urchins — were very much in evidence (Holaster,
MicY aster, etc.) ; and some were becoming still more like
ordinary bilateral animals, as the mouth was well in process

EVOLUTION IN THE PAST

of being brought forward from its old central position on the
under-part of the body. These creatures must have been
living on softer food than their ancestors, for the anatomical
alterations had been accompanied by a total loss of the
teeth.

SEA-LILIES Crinoids, or " sea-lilies," after much depression, revived
somewhat in the Jurassic ; but their fortunes do not seem
to have further improved in the Cretaceous Period. The
work of emancipation, however, from a rooted existence
was in progress ; and stemless forms were becoming more
prominent (Marsupites, Uintacrinus).
CORALS Reef-building corals were still greatly in force in parts of
central Europe. In some regions gracefully branching coral-
colonies, resembling the " sea-fans " of our own time, were
now to be seen {GorgoniidcB). And red coral is first met with
in this Period (Cor allium).
SPONGES Sponges with flinty skeletons were abundant ; and the
nodules of flint, found in the Chalk formations, probably
represent their remains, increased in volume by the accretion
of other flinty materials in the rocks.

Sponges fortified with six-rayed needles were spreading
far and wide (Hexactinellids) ; and species with the needles
wrought into elaborate frameworks, and possessing strong
roots composed partly of a flinty substance, were much in
evidence {Coscinopora, etc). Some of the forms resembled
the " Venus Flower Basket " of our own time, and added
not a little to the beauty of submarine Ufe (Ventriculites).
Prosperous also were four-rayed sponges and allied forms
(Tetractinellids, Lithisda). Indeed at no other time are they
known in such variety. Some of bud-like shape were pecuHar,
having developed long stalks well rooted at the base
(Siphonia). Sponges with lime needles shared for a time
the good fortune of their flinty brethren, but towards the
close of the Period they met with checks in their onward
career.

PROTOZOANS The lowest forms of animal life — Protozoans — were weU
represented by foraminifers and radiolarians. The former
must have been as sand-grains in the sea. By appropriating
lime held in solution in order to form their shells, and

HESPERORNIS

[To face page iii

CRETACEOUS PERIOD

III

"by force of prolificness, they became true rock-builders ; for
the chalk is largely composed of their shelly coverings. It
has been estimated that one cubic inch of chalk represents
the remains of more than a million minute organisms, mostly
foraminifers.

Along the coasts and estuaries birds of various kinds were birds
in evidence, water-habits having come greatly into vogue. As
the remains found all belong to the latter part of the Period,
a wide hiatus occurs in bird history, and great changes cause
no surprise.

Toothed birds, however, continued ; but the tail had
undergone important modifications. It did not now consist
of a long lizard-like structure decked with feathers. The
bone had been considerably shortened ; and the feathers
were doubtless so arranged as to spread out more or less fan-
wise as in the case of modern birds. Another link, therefore,
with reptiles had been broken. Nor were wings, so far as is
known, provided with usable claws.

Birds exhibited still more changes. Some genera, for
instance, had been through a series of modifications resulting
in the loss of the power of flying. It would seem from this,
that in certain regions birds must have found it safe and
convenient to abandon, more or less, aerial flight ; and that
their habits had been confirmed by successive generations.
In this way, through long disuse, a posterity had in time
appeared entirely deprived of power to fly. These Cretaceous
birds had little left to show that their remote ancestors
possessed usable wings ; for the bone of the upper part of the
fore-limb alone remained to testify to this. They may be
said, moreover, to have weUnigh lost their " land legs " ;
for their limbs turned outwards from the body and pedes-
trianism must have been a laborious proceeding.

The life of these birds no doubt was spent mostly in the
water, as in the case of grebes and divers. Indeed they
were, so to speak, compounds of those birds, and pro-
bably their ancestral forms. They had doubtless become
highly expert at catching fish, for their advanced speciali-
sation for aquatic life points to long acquaintance with
the art.

112

EVOLUTION IN THE PAST

Remains of them have been found in Europe (Enaliornis) ;
but these do not indicate creatures of large size. In North
America some forms attained a length of nearly four feet

(Hesperornis).

Whilst some birds had thus lost a long-neglected endow-
ment, others, suggestive of solan geese considerably under-
sized, had greatly improved their powers of flight. These,
as a result of long-continued flying habits, had gained a strong
framework for the wing, and also well developed breast-bones,
with which to cleave the air and water (Ichthyornis). They
had by no means grown out of affinities with reptiles to
the same extent as living birds. In addition to the presence
of teeth, connecting links remained in several parts of
the anatomy, notably in the vertebrae of the back-
bone, which were concave at both ends as were those of
early crocodiHan forms. They were also, as were the
diver-grebes, small-brained creatures for the size of their
bodies.

Other birds — derived from the same stock as the semi-
solans — were modernised, especially in being toothless. Some
apparently were a complication of storks and flamingoes
(Scaniornis) : others seem to have been forerunners of
cormorants (Graculavus). Other forms had descended from
a different stock. Some of these were rail-like birds (Telma-
tornis), some possessed close afftnities with the dunlins
of our time (PalcBotringa). Doubtless many birds of
various kinds haunted the inland valleys and plains, but
their remains have perished, or at least have not been dis-
covered.

VEGETATION The sylvan scenes of the early Cretaceous presented for
the most part much the same aspect as those of the Jurassic.
Sequoia firs were represented by primitive forms of the
" big tree " (5. gigantea), and the " red- wood " (5. semper-
virens). And these and other conifers, as well as ferns and
cycads, extended far and wide, with as yet no serious com-
petitors to dispute their long-held territories.
ANGIOSPERMS But in some unknown regions — possibly in the far north-
east of the North American continent — shrubs and trees of a
different character must for a long time have been developing.

CRETACEOUS PERIOD

113

Under the stress of climate and inter-competition these
vigorous growths had shown wonderful and varied resources
— notably in the formation of deciduous habits. The power
of adaptation, however, has its limits ; and, owing to the
increasing severity of climate, a time came when the various
species had for self-preservation to migrate to lower latitudes.
In the early Cretaceous there were distinct signs on North
American scenes of such migration. Here and there south of
Canada growths leaved like fig-trees, willows, sassafras, and
magnoUa were reconnoitring ; and as time went on, primitive
forms of oaks, poplars, birches, and other deciduous growths
joined the movement. Progress was necessarily slow. Every
inch of ground was more or less disputed by old-established
vegetation ; and the emigrants themselves naturally com-
peted with one another. But the new types pressed steadily
on, enlivening the landscapes with brighter foliage, and
greater display of flower. And so successful was the advance
that, in the course of the long Cretaceous years, they became
in some districts the dominant form of vegetation. " Horse-
tails " struggled on, and with some success, in their swampy
holdings ; but conifers and cycads — the latter especially —
disappeared from many long-tenanted positions. The most
progressive cycads (BennettitecB), that had given promise in
their well-protected seeds of plants of higher type than cycads
and conifers, (and, so far as is known, the nearest in develop-
ment to the new vegetation) became extinct long before the
close of the Period.

This invasion rather brings to mind the northern bar-
barians moving down on the Roman Empire. These Creta-
ceous hordes, however, were not barbarians of their kind.
They were true angiosperms, and in the advanced methods
they had developed for the production and welfare of their
seeds, they illustrated more strongly than any earlier growths
the principle of parental care.

In the early portion of the Cretaceous Period, though
somewhat later in time than in North America, some primitive
oaks, planes, and other angiosperms made their appearance
in what is now known as the Spanish peninsula. How the
seeds whence they sprang reached that territory — whether
I

114

EVOLUTION IN THE PAST

through the agency of birds, or by sea-transport, or by land-
connections which no longer exist — it is difficult to say.
Having, however, once obtained a footing, the invaders
gradually extended their range, being reinforced from time
to time by various other emigrants of their class. So success-
ful was the progress that in the latter part of the Period
fig trees, eucalyptus, oaks, poplars, grasses and other angio-
sperms had annexed large districts in Europe. But although
conifers were being displaced in many parts of Europe and in
America, they still flourished over vast areas on both conti-
nents. In addition to the nine points of the law in their
favour, the soil in many districts was doubtless more suitable
to them than to the new-comers.

Palms also were making their appearance. There is little
doubt they were descendants of some early forms of cycads.
This effort to confront new conditions was another sign of
the resourcefulness of that Order.
INSECTS Hosts of insects must have accompanied the new vegeta-
tion, for plants and insects, then as now, were doubtless
in many cases dependent on each other — the insects for food,
and the plants for the transference of their pollen. Bees,
butterfhes, and moths are helpful in f ertihsation ; but it is
impossible to say how far the vegetation was benefited by
insects at this time. The evidence of insect-hfe in the
Cretaceous is very meagre. Bees had appeared in the
Jurassic, but the evidence as to butterflies at that time is not
satisfactory ; nor is there better evidence in the Cre-
taceous. There is, however, good reason to think that
moths had by this time made their appearance (Tineidce,
TortricidcB).

MAMMALS Here then were trees, shrubs, and grasses as a table spread
for mammals ; but so far as is known these creatures
exhibited very little progress over their forerunners (Dryo-
lestes, Didelphops, etc.). They all appear to have been of
small size ; and no remains of forms of higher rank than
marsupials have as yet been discovered. Reptiles still held
the field. It is, however, extremely probable that in some
lands, the strata of which have as yet been very little
explored, mammals of higher type had come into being. But

CRETACEOUS PERIOD

115

whether this was the case or no, this new vegetation was not
to be enjoyed for long by grotesque plant-eating reptiles,
although they doubtless battened on it for a time. An inrush
of mammal life, no less wonderful than that of the new
vegetation, was not long to be delayed.

CAINOZOIC AGE

EOCENE PERIOD

The passage time from the Cretaceous to the succeeding
Eocene is shrouded in darkness : and the " new dawn "
follows a long night. It is as if the lights in a playhouse had
been abruptly extinguished, and after a lapse had been
restored, disclosing a stage crowded with new characters.

The transition times were doubtless of long duration, and
full of stirring events ; but their archives for the most part
have either been destroyed, or have yet to be discovered.
The results, however, of what then took place are plain
enough. There had been a great elimination of old forms of
reptile and other life ; and mammals had become dominant.
Dinosaurs, herbivorous and carnivorous, had one and all
vanished from the scene — iguanodonts with their spiked
thumbs, stegosaurs with their battlemented backs, and the
rest of the fraternity. Old Triceratops with his thrice-horned
head, and Ehzabethan frill, seems to have held out as long as
any ; but fortune failed him at last. In short, the old reptile
nobility, unable to march with the times, had been swept
away. Nor had ichthyosaurs, plesiosaurs, mosasaurs, and
flying lizards fared any better. They had all quitted the
stage, never to return.

Mammal life, now triumphant, was represented by forms
far surpassing in variety and importance the primitive
creatures known in earlier times. The predominance of
mammal over reptile life can hardly have been obtained by
brute force ; for there is no reason to suppose that primitive
mammals were either warriors or flesh-eaters. Various
geographical and climatic changes may have helped to shift
the sovereignty • but the superior intelligence and higher

Ii6

EOCENE PERIOD

117

moral qualities of the mammals were undoubtedly great
factors in the dynastic question.

So far as evidence goes none of the mammals before this
Period were of higher rank than pouched creatures, bringing
forth their young in an extremely immature condition. And
it is not until the beginning of Eocene times that remains of
placental animals are found ; i.e. of animals whose young
are well nourished and developed before birth.

There can be little doubt that the Eocene placentals
had been developed from marsupials of earlier days ; and as
might be supposed they retained close affinities with the latter.
They were doubtless more intelligent ; but the brain, as
with marsupials, was small in proportion to the size of the
body.

The animals had not become so far differentiated as to
make them closely comparable with any members of the
existing mammal Orders. But intermixed though they were
in affinities, they exhibited some notable differences. It is
clear, therefore, that some important divergences had taken
place before the " new dawn."

Some of the first-known creatures wandering about Eocene CONDY-
prairies and woodlands, are called the " knuckle- jointed " larthra
(Condylarthra), owing to a peculiarity in the structure of
their feet. The animals were of small size, and probably
bore greater resemblance to coneys (Hyrax) than to any
other creatures now living. They differed markedly from
coneys, however, in having long tails and five-toed feet.
Their toes cannot be said to have been either hoofed or
clawed ; but the horny sheaths with which they terminated
showed a tendency to become hoofs rather than claws. To
judge from their teeth, the " knuckle- jointed " creatures
subsisted on a vegetation diet, varied occasionally by feasts
on insects.

Other forms, probably suggestive of bear-cubs and baby amblypods
hippo's rolled into one, are known as amblypods, as they
possessed feet of a short and stumpy character. They also
were five-toed animals, as, no doubt, was the rule with all
primitive mammals — and the toes seem to have been guarded
by little hoofs {Pantolamhda). The " blunt-footed " creatures

Ii8

EVOLUTION IN THE PAST

may not have been averse to flesh when obtainable without
risk, but their staple fare consisted probably of vegetables.
CREDONTS Small, long-tailed creatures of more bear-hke appearance
were also abroad. These possessed teeth of a trenchant type,
showing that flesh-eating had become a habit (Arciocyon).
In the shape of the skuU, and the claw-like termination of
the feet, they were also developing in the direction of true
carnivores. Some mammals, it is clear, had passed out of the
Age of Innocence.

These primitive flesh-eaters are classed as Creodonts
(" flesh -teeth ") ; but their close relationship with the
" knuckle- jointed " vegetarians was attested by many ana-
tomical features.

Mammal life was thus in process of important develop-
ments, foreshadowing the two great Orders of ungulates or
hoofed animals, and carnivores. Nor was the promise of
future development limited to those directions. Other
contemporary animals seem to have been setting out to
EDENTATES found the Edentates — the somnolent Order which com-
prises sloths, ant-eaters, and armadillos. Edentates (" tooth-
less ") is not altogether a happy name ; for many edentates
possess at least cheek teeth. Teeth, however, are not a
strong point with any living members of the Order.

These Edentate pioneers — known as Ganodonts — were
about the size of small dogs ; were well supplied with teeth ;
and were probably not so drowsy as their present repre-
sentatives (Hemiganus). Their dentition became somewhat
reduced even during the early part of the Period. In
the course of time teeth, and it may be added toes and tails,
have frequently been in the melting-pot of Evolution ; and
edentates were destined to undergo great dental suppressions
in times to come.

INSECTIVORES Other developments in the mammal world were also taking
place Insectivores — the Order which comprises shrews,
moles, and hedgehogs — had been foreshadowed so far back
as the Jurassic Period, at least in marsupial form. In early
Eocene times shrew-like creatures of higher rank than
marsupials were certainly poking about in the thick grasses
(Adiposorex).

EOCENE PERIOD

119

Yet other creatures, living probably in densely wooded lemurs
regions, were developing in the direction of lemurs. Some of
these were as yet but little distinguishable from insectivores
{Mixodectes, Indrodon, Protoadapis) ; whilst others seem to
have had close affinities with the primitive flesh-eaters
(Chriacus).

When, therefore, the curtain rises on the first-known scene
of the " new dawn," there were not only new but highly
important characters on the stage — forerunners of hoofed
animals, carnivores, edentates, insectivores, and " four-
handed " animals. The Orders were certainly not sharply
distinguished from one another, but the evidence of progress
is not thereby deprived of its significance. It is clear that
Evolution had been busily at work ; and one may well ask
where. The remains of the " knuckle- jointed " and the
" blunt-footed " animals have been found in North America ;
the evidence of the insectivores comes from Europe ; whilst
the primitive flesh-eaters and the lemur-like animals left
their bones on both continents. It does not, of course, follow
that any of these animals originated in North America, or in
Europe. No traces of their immediate ancestors have been
found in either country ; and it is probable that they were
emigrants from other lands. Evolution had probably been
at its highest activity in parts of Asia and Africa ; and if
ever the missing links in early mammal life be forthcoming,
it will probably be from the unexplored strata of one or other
of those continents. Africa, it is thought, contains the more
hopeful strata.

Marsupials, no doubt, continued to flourish ; but they MARSUPIALS
were now to play a subordinate part in mammal Ufe.
Opossums were apparently in some force in Europe during
this Period, and also in North America. In Australia, which
in pre-Eocene times must have lost its mainland connections,
marsupial life was no doubt undergoing special developments
in the absence of animals of higher rank.

As the Period advanced, the " knuckle- jointed " (Condyl- CONDYL-
arthra) were in evidence in some variety. One of the most arthra
remarkable forms is known as Phenacodus — represented both
in Europe and in North America.

120

EVOLUTION IN THE PAST

PHENACODUS Phenacodus affords a good example of what may be called
an omnibus animal — that is, a highly generalised creature
containing in its anatomy several features, which in course
of time are not found combined in any one form. It had
affinities with deer, pigs, tapirs, horses, and apes, and was
tailed like a carnivore.

Some members of the genus did not exceed small dogs
in size ; whilst some were as big as tapirs. The fore-hmbs
had apparently some grasping power ; and the toes ter-
minated with sheaths of a mixed hoof and claw description.
The teeth were adapted to an omnivorous diet ; but they
were not of a powerful character. And as the skull indicates
but slight mental calibre, it is clear that these animals were
not forcibly endowed either in mind or body : and long
before the close of the Eocene they and closely allied forms
became extinct.

Their great foes, no doubt, were the flesh-eaters, which
greatly increased in the course of the Period, and became of
more decided carnivorous type. Nature, however, does not
leave comparatively defenceless animals without resources ;
and the phenacodi when seriously threatened must frequently
have found salvation in flight.

They were, no doubt, capable of speedy movements ; for
they were of slender build, and although they may have
walked in a more or less plantigrade manner, the limb-
construction shows that in running they no doubt raised
themselves well on the toes ; and were, therefore, capable
of the digitigrade method characteristic of fleet-footed
mammals.

LOPHIODONTS More or less closely related to the Phenacodi were other
animals known, on account of a peculiarity in tooth-structure,
as lophiodonts (" crest-tooth "). These were undoubtedly
hoofed creatures ; and when in motion the weight of the
body was thrown entirely on certain of the toes, with the
heel or hock high-raised. As a result of disuse some of the
shorter toes had become atrophied ; and the foot, thus
rendered more compact, was better adapted for fast running.
The most notable of these animals were about the size of
HORSES fox-terriers ; and they probably roamed about in herds

HYRACOTHERIUM
The most primitive horse-like form known. Remains found in the London Clay

[To face page 121

EOCENE PERIOD

121

(Hyracotherium). The fore and hind limbs were four toed
and three-toed respectively ; but in a few cases there was
a rudimentary fifth digit or " thumb " on the fore-leg
(Eohippus). The teeth were not strongly crowned, and seem
to have been adapted only for succulent vegetation. In
appearance the creatures were somewhat horse-like ; and
indeed they are generally regarded as remote ancestors of
modern horses.

In the course of the Period this branch of the lophiodont
family made distinct progress. The teeth became harder
and more like those of living horses ; and were capable,
therefore, of masticating a more varied vegetation. As a
result probably of an extended dietary, the animals in-
creased in size, and became as big as foxes (Pachynolophus,
Orohippus). The toes underwent no reduction in number.
The animals, however, were evidently rising more on the feet
in order to obtain greater speed : for the second toe — the
central of the primitive five — had become considerably
developed ; and the other toes had diminished in size.

Other members of the highly-charged lophiodont family tapirs
were developing in the direction of tapirs (Systemodon).
Excepting as regards the teeth, they can have differed but
little from the equines. They had probably the same number
of toes as those animals (4-3) ; and that indeed is the
number possessed by modern tapirs. They had, it is true,
an atrophying digit on the hind-foot, and to that extent
possessed an " extra " toe. They had, moreover, two teeth
more than their now hving descendants. These excesses,
however, were not serious obstacles in the path to modern
tapirism.

In mid-Eocene times yet other members of the lophiodont rhino-
family were, it would seem, diverging in the direction of ceroses
rhinoceroses (Hyrachyus). These animals were confined to
North America.

In late Eocene times there were certainly some big brutes
with rhinoceros-like skulls on that continent (Titanotherid).
Many of them were destitute of horns (Palceosyops) ; but
apparently the snouts of some were being prepared for those
■weapons (Telmatotherium). Their later representatives, how-

122

EVOLUTION IN THE PAST

ever, never became rhinoceroses ; nor indeed were they ever
modified so far as to bear close resemblance to any animals
now in existence. Other forms, then Uving, seem to have
been developing more steadily on the hne (Amynodon) ;
but neither did any of their descendants ever really reach
the goal. Allied to these were some European forms, of which
very little is known (Cadurcotherium).
PAL^o- The true rhinoceroses of the future were possibly derived
THERES from some animals named Palaeotheres — first known in mid-
Eocene times. These creatures, so far as evidence goes, were
confined to Europe ; and were probably another offshoot of
the great family (Lophiodonts) whence the budding equines
and tapirs had sprung. They certainly much resembled.
tapirs, especially in the shape of the skull. The Palaeothere
escutcheon, therefore, was rather confusedly charged at this
time.

In late Eocene times the palaeotheres varied greatly in
size, and some forms were to be seen as big as rhinoceroses.
The skull, so far as is known, retained in all cases its old
tapir shape ; and horns were not even in faintest promise.
A.MBLYPODS Animals with so-caUed " stumpy " feet and of bear-cum-
hippopotamus build (Amblypoda) — in view at the dawn of
the Period — made considerable progress. In course of time
forms of heavier structure than their forerunners, and in
some cases as large as oxen, made their appearance {Cory-
phodon). The heads of these animals were large, and
lightened by air chambers ; and were certainly not burdened
with brains. Some of the animals, when locomoting, were
developing a habit of rising on the toes of their broad,
spreading feet. As a rule, however, they probably walked
more or less flat-footed like a bear. Flight in times of
danger was not with them a matter of vital importance ;
for they were doubtless able to show fight, as evidenced by
their canine teeth, which had been developed into tusks.

Coryphodont prosperity in Europe was not enduring, for
the animals became extinct in that part of the world long
before the close of the Period.

The disappearance of Coryphodonts brought Amblypod
annals to a close in Europe. In North America these

CORYFHODON
Remains found in Europe and North America

[To face page 122

EOCENE PERIOD

123

creatures disappeared about the same time : but in late
Eocene times the Order was represented on that continent
by beasts, with still less brains, it is true, but of much more
imposing aspect (Dinocerata). Some of these animals were as
large as elephants, and were well armed (Dinoceras). Not
only were their upper canines developed into powerful tusks ;
but their heads were furnished with four horns, and a pair of
knobs adorned the snout. They had also improved on their
forerunners in locomotive powers, for they had become
distinctly digitigrade. One might suppose that such lordly
creatures would have held their own in the world for a long
time ; but such was not the case ; for at the close of the
Period they became quite extinct. There is little doubt that
intelligence was beginning to play a very important part in
animal progress ; and as regards brains these animals were
excessively deficient. Dinoceras is suggestive of a battle-ship
in charge of a child.

Meanwhile the Order of Rodents (which comprises squirrels, rodents
hares, rats, and other animals with chisel-shaped incisor
teeth) was coming into view. As far back as Jurassic times
certain primitive mammals were developing teeth of a rodent
or gnawing type : but so far as is known neither those
animals, nor their Cretaceous successors, were much advanced
on the way to becoming true rodents. In early Eocene
times much more clearly defined rodent mammals were in
existence (Esthonyx). These on account of their " tearing "
teeth are known as Tillodonts, and they are generally re-
garded as the ancestors of living rodents.

As regards teeth these ancestral forms were more liberally
supplied than are the living representatives of the Order.
Abundance of teeth, however, was a great feature with early
mammals. Dental modification, in course of time, resulted
in reducing the number, and increasing the efficiency of the
remainder for the various habits of life that were being
adopted. This reduction appears, geologically speaking, to
have been a rapid process in the case of the rodents ; for as
the Period advanced one pair of the upper incisors was
disappearing (Anchippodus). Provision was at the same
time being made for the continuous growth of the large

124

EVOLUTION IN THE PAST

rodent-like incisors. These teeth were, no doubt, being
submitted to ever-increasing demands, and their rapid
wearing away necessitated a new economy.

Eocene rodents were in a somewhat mixed condition of
development, but dormice and squirrels were, so to speak,
coming out of the hotch-potch.
EDENTATES Edentates of somewhat modern aspect were also appearing.

The animals, indeed, save for the absence of a bony shield,
seem to have closely resembled armadillos now living
(Metacheiromysis, N.A.).
ELEPHANTS A glance must now be taken at Africa, where some highly
important animals were in process of evolution. Valuable
knowledge on this subject has been obtained through the
exertions of Mr. Beadnell, Dr. C. W. Andrews, of the British
Museum, and other explorers.

From discoveries which he made in igoi near Lake Moeris
in the Fayum Desert (Egypt), Dr. Andrews has shown that
in mid-Eocene times forerunners of elephants were Uving in
Africa (Moentherium). These interesting quadrupeds stood
about three feet at the shoulder ; and were long enough in
the neck to get their heads to the ground. Their sloping
faces were certainly unlike the almost vertical face of living
elephants ; but the bones of the skull were falling into position
in a manner peculiar to proboscideans ; and there was at
least promise of a trunk. Certain of the incisor teeth in the
upper jaw were developed into small tusks ; and on the front
part of the lower jaw a pair of tusk-like teeth protruded.
The cheek teeth were much of the pattern of those of
elephants of later times.

These " beasts of Moeris," no doubt, wandered about in
herds ; were quite at home in the water ; and subsisted
chiefly on marsh and aquatic vegetation.

They had well-developed brains for their size ; and their
intelligence was probably much above the average of the
time.

It is a matter of no small interest to have these primitive
forms brought into view ; and the knowledge gained of
elephants " in the making " does not stop here. In later
Eocene times " beasts of Moeris " were still living in Egypt ;

MOERITHERIUM

[To face page 124

EOCENE PERIOD

125

but other forms, probably derived from them, and of a more
advanced type, were then on the scene (Palceomastodon).
These animals, like their forerunners, were fairly long in the
neck. They were certainly bigger animals, and in some
cases must have stood fully six feet at the shoulder. The
lower jaw had been elongated considerably, and terminated
— as with the " beasts of Moeris " — with tusks of small size,
usable for digging and uprooting purposes.

This lengthening of the lower jaw is perhaps the most
remarkable feature. The chief purpose of it seems to have
been to form a support for the trunk, which was in process of
development. Probably the short proboscis already pos-
sessed at its extremity a fair amount of prehensile power ;
but it was not yet sufficiently developed to be left, so to
speak, to itself. A developing organ intimately connected
with breathing and feeding must have required very careful
nursing ; and the under jaw was acting as a sort of foster-
mother.

These creatures possessed sloping faces like the Moeris
animals, but the skull was more elephantine in shape. They
were also approaching true elephants as regards teeth ; for
these were fewer in number than in the more primitive forms,
and some were considerably enlarged.

These more elephant-like beasts lived, it is supposed,
more or less habitually on land. Here they could obtain a
more varied and substantial vegetation than that which
satisfied their lake-dwelling relatives. They were certainly
more enterprising, and probably far more intelligent than
the latter.

Some doubtful remains of swine have been found in the
same district (Geniohyus Andrewsi) ; but our eyes must
revert to North America for a clearer view of porcine patri-
archs. Here in mid-Eocene times animals were certainly
living more or less distinguishable as swine (Homacodon).
Pig-life on these scenes was beginning in a small way ; for
the creatures were not bigger than hares. Although in
common with mammals of primitive type their feet were
five-toed, they were practically four-toed animals, as one of
the digits on each foot had been withdrawn from active

126

EVOLUTION IN THE PAST

service. That reduction at the extremities, however, left
them with twice as many functional toes as living pigs
possess. Tusks, characteristic of later boars, were not as yet
developed ; but the enlarged canine teeth gave promise of
these.

In later Eocene times porcine forms of larger size were
wandering about Europe {Choeropotamus). Some of these
seem to have had close affinities with monkeys, showing the
entanglements of mammal life at this time (Cebochcerus).
The toe question cannot be determined, for these quaint
creatures have come down to us minus their feet.
BATS At the time when pig-life was coming into view. North
American life was also being diversified by small mammals
that had acquired the art of flying (Vesperugo). These
" wing-handed " creatures can hardly as yet have exhibited
much variety of form, and many of them were probably poor
flyers. Still, there were forms among them that did not differ
much from some of the numerous kinds of bats now hving.
Unfortunately no forerunners of these new invaders of the
air have been brought to light ; and, so far as geological
evidence goes, bats fluttered into the world as suddenly as
the flying lizards seem to have done in earher times.
Probably their ancestors had branched off from some insec-
tivorous animals, such as were living at the very commence-
ment of the Period. The wings, it may well be supposed, had
originated as simple folds of skin stretching from hmb to
limb, resembling the parachute of the flying squirrel of our
own time (JPteromys).

Well-developed bats were also in Europe in the course of
the Period, but they made their appearance later there than
on American scenes.
PRIMATES Lemur-like creatures, holding affinities — as did the bats —
with primitive insectivores, were visible, it may be re-
membered, on the earliest glimpse of Eocene hfe. They
were followed before mid-Eocene times by various forms,
mostly of a more definite type (Tomitherium, Microsyops,
Hyopodus, etc.). Small, fox-faced, large-eyed creatures were
some of these, with well-developed brains indicating mental
powers of a comparatively high order (Anaptomorphus).

PAL.5:OMASTODON

[To /ace page iz6

EOCENE PERIOD

127

Their teeth, it may be mentioned, were thirty-two in number
— as with human beings.

All these lemurine animals were probably of more or less
arboreal habits — and " monkey-puzzlers " had ceased to be
a prominent feature of the forests. Some of the creatures
can hardly have been such accomplished climbers as forms
now living, as they were deficient in grasping power, not
being able to oppose the thumb to the other digits (Pelycodus).

Later in the Period new types of lemur-like animals
appeared. All of these were much more numerously toothed
than lemurs now living. Some of them, to judge by their
skulls, were developing into apes {Adapts).

Some quite recent discoveries in the Fayum of Egypt (Dr.
Max Schlosser, 1910) prove the existence in late Eocene
times of some transitional creatures of a more monkey
character (Parapithecus). And some forms (Propliopithecus)
may have belonged to a stock whence sprang two lines of
evolution, one leading to anthropoid apes, one to human
beings.

The peace and quiet of herbivorous mammals must often carnivores
have been disturbed by carnivores. Small " flesh-toothed,"
bear-like forms were, it may be remembered, living at the
commencement of the Period. As herbivorous mammals
increased in number and variety, so also did their natural
foes. The latter in mid-Eocene times were doubtless closely
approaching the status of true carnivores ; but they were
less effectively toothed than later forms, as none of their
back teeth had as yet been so highly modified to tearing uses.
In outward form many of them more or less resembled
wolves, hyaenas, polecats, and civets (Pachycena, Sinopa,
Stypolophus, PalcBonictis, Proviverra, etc.) ; and in the
matter of speed they were doubtless superior to their more
or less flat-footed forerunners. Their intelligence, no doubt,
was being developed owing to the skiU and cunning they had
to practise in order to get a living. They were, however,
smaU-brained animals, resembling in this respect their far-
back marsupial ancestors, and falling, therefore, far short
of the brain power of modern carnivores.

In North America strange forms were abroad. Some of

128 EVOLUTION IN THE PAST

these were long-tailed, web-footed creatures ; and appear
to have been compounds, so to speak, of cats and otters
(JPatriofelis). Being of aquatic habits they probably sus-
tained themselves chiefly on fishes and reptiles. Nothing is
known of their later history. It was at one time supposed
that they were remote ancestors of seals ; but this compli-
ment is not now paid to their remains.

Other animals, living in the same region, were long-bodied
creatures, and appear to have been an interweave, so to
speak, of wolves and hyaenas (Mesonyx). In the course of
their lives they sampled probably a great variety of meat,
fresh and otherwise ; but it is supposed they had a special
liking for turtle-flesh.

Flesh-eaters of old type still abounded in late Eocene
times ; and new forms, rather smaller than hyaenas, made
their appearance (HycBnodon). The teeth of these animals
had been modified, but they were not so much of butcher
pattern as those of true carnivores. They were small-
brained brutes, and rather weak in the limb. They ranged,
however, far and wide ; for remains of them have been found
in Europe, Egypt, and North America.

Before the close of the Period some of the flesh-eaters,
both in tooth and limb, closely resembled living members of
the Dog family (Cynodictis). They may, therefore, be
described as true carnivores. Owing to the shape of their
skulls they must have looked more like civets than dogs.
They were in a sense, therefore, an amalgam of animals now
belonging to different families.
RUMINANTS The dangers of feeding in public had compelled some of
the herbivores to adopt a new mode of living. Among the
hoofed animals of late Eocene times forms appeared who, to
judge by their teeth, bolted vegetable food and then betook
themselves to some obscure retreat, where the pabulum
was brought back to the mouth to be chewed and re-
swallowed.

Among these incipient cud-chewers, or ruminants, were
certain animals of somewhat pig-like aspect (Anthraco-
therium). Others were small, long-necked, long-tailed crea-
tures of deer-like appearance (Anoplotheria). The latter

EOCENE PERIOD

129

" defenceless " animals were, as their name suggests, not
built on martial lines, and must have trusted to flight when
disturbed in their ruminations. They were probably good
swimmers, and no doubt used their long and exceptionally
strong tails to speed their passage through the waters.

Other forms were gazelle-like in appearance (Xiphodon),
and about the size of chevrotains. They also were defence-
less animals, so far as regards actual weapons.

All these primitive cud-chewers seem to have been con-
fined to Europe ; but North America was not without
animals of similar type (Protoreodon). Those, however, were
not so far advanced in ruminancy as the European forms.

The nearest relatives at the present day of the early
ruminants are, no doubt, the chevrotains. These are the
smallest hoofed animals now living ; and are of a primitive,
composite character, holding affinities both with pigs and
deer. In possessing tusks they certainly surpass their
defenceless forerunners.

On North American scenes, in late Eocene times, animals,
more or less allied to the early ruminants, had set out,
apparently, to found the Camel family (Protylopus). They
were of diminutive size — not above a foot in height. But
all developments in Nature resulting in new types were
probably initiated by very small creatures of their kind. It
is not surprising, therefore, that Camel-life commenced in a
small way.

Some remarkable animals were living in Egypt in late
Eocene times. Coneys now are not larger than rabbits, but coneys
here were some as big as donkeys, and well-tusked to boot
(Megalohyrax Andrewsi). These giants were possibly the
wisest of the then Egyptians. Even the degenerate coneys of
Solomon's time were " exceeding wise."

But there were some far more remarkable forms in Africa
than gigantic coneys. Remains of these more notable brutes
were first found by Mr. Beadnell in 190 1. As the discovery
was made in a locality where the Egyptian Queen Arsinoe arsinoi-
had a palace, the animals have been named after that unhappy therium
lady (Arsinoitherium).

These strange creatures were in some cases as large as

130

EVOLUTION IN THE PAST

good-sized rhinoceroses, and they somewhat resembled those
creatures in appearance. Their skulls were adorned on the
forehead with a pair of small horns, whilst the greatly en-
larged nasal bones supplied a second pair of comparatively
huge dimensions. A good-sized Arsinoitherium was there-
fore an imposing figure. He certainly was the outcome of a
long course of evolution ; and was, indeed, at the end of it,
for his family is not known after this Period. As to his
ancestry zoologists as yet know little more than did the
creature himself.

Some forms of primitive elephants were living in his
neighbourhood ; and Arsinoitherium may have enjoyed the
society of these fellow-vegetarians. But he stood out in
strange contrast with them. They were in the dawn of
their history : he was hasting to his setting.

Other discoveries have been made in Egyptian strata
which show that some mammals had taken to an aquatic life,
after the manner of certain reptiles in earlier times.

SIRENIA Some of these were " sea-cows " of primitive type, and
are represented to-day by the dugongs and manatees
{Eotherium, Eosiren Andrewsi). These pioneers seem to
have been related to the small, marsh-dwelling elephants ;
but they must long have quitted the original fold. In
possessing hind-limbs they presented a notable difference
from sea-cows now living. This difference, however, is not
to be wondered at ; for the appendages, indispensable to
their land-frequenting ancestors, must have been too well-
developed to dwindle away rapidly. Nor had the hind-
limbs in the next Period entirely disappeared.

WHALES Other mammals that had taken to the water were toothed
much as the primitive carnivores, but resembled whales as
regards the skull (Protocetus). These creatures were rather
long in the neck ; but their bodies were assuming a fish-like
shape ; and their " arms " were probably being modified into
fins. The supersession of lungs by giUs was not to be expected ;
for there was no dormant gill-apparatus to be aroused to
action.

These creatures were followed during the Period by
similar forms : but these had undergone dental modifica-

EOCENE PERIOD

tions (Prozeuglodon), and in some cases the teeth had been
reduced in number (Zeuglodon).

These pioneer, whale-like forms may have been ancestors
of the toothed whales (Odontoceti), represented to-day by
sperm-whales, dolphins, and porpoises. They probably pos-
sessed, like the incipient sea-cows, usable hind-limbs. Re-
mains indeed of such appendages, although not externally
visible, are found in living whales.

Before the close of the Period these adventurous mammals
had greatly extended their range, having found their way
to North and South American seas. Here some of them
attained gigantic proportions.

Whether persecution by some carnivorous reptiles, a
gradually developed taste for the salt-water population, or
geographical changes impelled the first adventurers to put
out to sea cannot be determined. The experiment at any
rate was attended with success ; and whales — no less than
sea-cows — have never since shown a disposition to quit the
adopted element.

Eocene bird-life, as may be supposed, has its surprises birds
as well as mammaldom : and it can only be very imperfectly
linked with the bird-life of the preceding Period.

Toothed birds had become extinct at the close of the
Cretaceous, and another affinity with reptiles had been
completely lost. There were, however, some gannet-like
birds in early Eocene times with what may be called false
teeth, for their beaks were notched and serrated like the
edge of a saw (Odontopteryx).

Forms heralding the Albatross were now in being (Argil-
lornis), and geese-like birds as large as ostriches (Gastornis).
Rails, more or less foreshadowed in Cretaceous times, seem
now to have been established (Gypsornis) ; and some related
forms — apparently primitive cranes — were wandering about
the swamps (Palceogrus). Flamingoes and storks, fore-
shadowed in a composite ancestry in the last Period, had
now, so to speak, parted company (Agnopterus, Propelargus) :
and birds derived from the same stock, and resembling ibises,
were also on the scene (Ihidopsis). Some forms more or less
nearly related were herons of primitive description (Prohe-

132

EVOLUTION IN THE PAST

rodius). Descendants of the Cretaceous dunlin-like birds
were now in some force (Tringa) ; and birds of a kingfisher
type were making their appearance (Halcyornis). In far-
southern seas some relatives of the Diver-grebes of the last
Period, specialised as penguins, were hobbling about, and busy
among the fishes (PalcBeudyptes).

The feathery tribes were not living in a state of universal
harmony. Various falcony forms — descended from the same
stock as the flamingoes and herons — were now on the wing.
Some of these were blends of falcons and vultures (Lithornis),
and a few were true falcons (Falco). Other birds of prey
were compounds of eagles, buzzards, and ospreys {Palceo-
circus). Some primitive forms of owls were also making
things uncomfortable (Bubo). Among the birds of milder
manners, some apparently were godwits (Limosa) — relations
of the dunlin-like birds. Hornbills (Cryptornis), woodpeckers
(Uintornis), and swifts (Mgialornis) — all distant relatives of
the owls — were also in being. Ancestors of modern game
birds were coming into view. Some were quail and caper-
caillie of primitive character (Coturnix, Tetrao) ; others were
partridges somewhat obscured by strong guinea-fowl and
turkey features (Taoperdix). Numerous " sparrow-shaped "
birds (Passeriformes) such as nuthatches (Sitta), and starlings
(Laurillardid) were enlivening the woodlands with their chirps
and chatterings. And sounds more melodious than these may
have been heard, for remains of larks and warblers have also
been brought to light (Protornis, PalcBgithalus).
VEGETATION The sylvan scenes are met with after a break in their
history ; but no changes, comparable with those in animal
development, had taken place in the interval. The new
vegetation had established itself far and wide in the Creta-
ceous Period, and on many scenes had gained a predominance
long held by cycads and conifers. Since then it had carried
its conquests further ; and in its exuberance had become
enriched with many new varieties and species.

Grand must have been the verdant display in some regions.
In the neighbourhood of Liege, for instance, early Eocene
plant remains have been found in abundance. Here oaks
of many species, and chestnuts were luxuriating in forest

EOCENE PERIOD

133

wealth, along with cinnamon trees, camphor trees, laurels,
ivy growths, guelder-rose shrubs, and azaleas ; whilst here
and there yews, firs, pines, and cypresses recalled the sombre
sway of earlier times. In some parts of France walnut trees,
limes, alders, and willows were living in the neighbourhood of
bamboos, palms, tree-ferns, vines of Asiatic type, and many
plants of sub-tropical character.

The association of these various growths is remarkable,
for one would suppose that the climate, so to speak, could
not befriend them all. One, therefore, is led to think that
plants had more plastic constitutions then than now. Adapta-
bility, however, had its limits, and as the Period advanced
troubles began.

Much remains to be known about Eocene plant-life ; but
it is certain that, in some regions, it came to be seriously
affected by a great rise of temperature. England, for
instance — which was and had been from very early times
part and parcel of the continent — yields evidence of this.
It is clear, from remains of plant-life in the Eocene London
Clay, that before the Period was far advanced the heat must
have become excessively trying to some of the growths of
far northern origin. There is little doubt indeed that many
succumbed in consequence. Shrubs and trees well adapted to
higher temperature were ready to supply the vacancies ; and
naturally made the most of their opportunities. Sabal and
Nipa palms with fan-shaped leaves. Custard Apple trees,
and many species of Acacia extended their sway. Melons
and gourds revelled, and multiplied in the warmth. Very
different, therefore, was the vegetation from that now on
and about the site of London. And the scene was ren-
dered still more strange by the presence of crocodiles
and turtles, and the big gannet-like birds with notched
beaks.

These climatic conditions were to continue for a long time.
The leaf-beds of Alum Bay and Bovey Tracey yield evidence
of a heat-loving vegetation in mid-Eocene times. Fan palms,
and feather palms, screw pines, eucalyptus, nettle, and
spindle trees, and various kinds of climbing plants, now more
or less confined to the tropics, adorned the scenes. Similar

134

EVOLUTION IN THE PAST

evidence is found in other parts of Europe ; whilst in North
America palms and bananas were thriving in latitudes that
now are temperate.

The heat, however trying to many of the more robust
forest trees, did not wholly overcome them. Oaks, planes,
beeches and other deciduous growths, if banished from the
lowlands, could still live and prosper on neighbouring hill-
heights, and high table-lands.

The warmth was doubtless welcome to the reptiles. These
animals, it is true, had been deposed from leadership in
creation, but they continued to play a great part in Nature's
economy.

CROCODILES Crocodiles were present in vast numbers ; and many of
the waterways must have been held by them in force. The
ability to drown prey, without self-drowning, had now
become the common heritage of all crocodiles. Earth, there-
fore, was not a complete elysium, even for the most powerful
of the mammals.

ALLIGATORS Alligators, known only in North America in the last
Period, were now displaying their physiognomy in Europe
(JDiplocynodon).

CHELONIANS Chelonians were widely dispersed, and in greater variety
than in Cretaceous times. Descendants of some Cretaceous
tortoises of amphibious habits had now quitted the dangerous
vicinity of crocodiles, having taken to residing permanently
on land (Hadrianus). Here they must have competed with
birds, as well as with lemurs and other mammals, in raids
on worms, snails, and insects ; but some of them, no doubt,
were becoming vegetarians. Among those that continued
land-and-water habits, some differed very Uttle from the
marsh-tortoises of our own time (Emys). Descendants
also were on the scenes of forms that, so far back as in
Triassic times, had been experimenting with elongated necks.
The experiment was meeting with some success ; for well-
developed long-necked creatures were now in evidence
(Rhinemys). The long neck, no doubt, brought advantages in
the matter of obtaining food, and of keeping a good look-out
against dangers. But it had its risks, for it could not be
drawn back within the walls of the carapace. Long-necked

EOCENE PERIOD

135

tortoises, at the present time, are known only south of the
equator.

The move to marine hfe initiated by some Jurassic
tortoises, and further developed by Cretaceous forms, con-
tinued without serious check. And sea-tortoises, or turtles,
were now becoming a power in the seas. Leathery turtles
(so-called from the leathery skin which does duty on the
carapace for the ordinary bony plates) were in existence :
and some large forms were enjoying life on the site of London
(Eosphargis).

Lizards were now decidedly more recognisable as such lizards
than in earlier times. Not only iguanas, but monitor lizards,
and creatures of chameleon type basked in the Eocene sun-
shine {Iguanavus, Tinosaurus, ChamcBleontidcB).

Snakes were also in being. These had probably sprung snakes
from some ancient lizard-like forms that had more or less
lost their limbs. Those ancestral creatures, it may be sup-
posed, had found it more advantageous in obtaining food,
and for self-preservation generally, to move along by the aid
of their ribs ; and as the result of disuse the limbs became
atrophied. Pythons, it may be mentioned, retain vestiges of
hind-limbs.

The Eocene snakes of which remains have been found seem
to have been of aquatic habits, and closely related to the
pythons of our own time {Palceophis, etc.). In Egyptian
waters some of the animals were nearly thirty feet in length
(Gigantophis garstini). No venomous snakes, it would seem,
had as yet appeared.

The long-languishing ranks of amphibians were now amphibians
recuperated by the appearance of little creatures in a tail-
less condition. At least they were probably so as adults,
having, in juvenile days, used their tails, first for swimming
purposes, and then as food for the body.

These, the first-known of the frog fraternity, seem to have
been much of the stamp of certain small frogs now living in
India (Oxyglossus).

Fishes had meanwhile been developing into a decidedly
modern aspect. Shark-life was being further diversified sharks
by the evolution of forms to which the blue-sharks of our own

136

EVOLUTION IN THE PAST

time are closely allied (Carcharias). And eagle-rays, fore-
shadowed in the last Period, were now represented by some
gigantic specimens (Myliohatis). Electric rays were also in
evidence (Torpedo). These, so far as is known, were the first
creatures equipped with electrical organs for the battle of
life.

GANOIDS Flexibly finned ganoids, although greatly reduced at the
close of the Cretaceous Period, were in some force in the
Eocene. Deep-bodied pycnodonts, for instance, with power-
ful teeth still held their own. They apparently differed in
no respect from their Jurassic forefathers ; and they remained,
moreover, practically unchanged until the close of the Period.
In common with other part-modernised forms — suggestive
of old bottles carrying a modicum of new wine — they
then became extinct. With better outlook were the descen-
dants of the sturgeon-like fishes. Various forms of these
seem to have differed little, if at all, from species of sturgeon
now in existence. Long-nosed garpike were also abroad
(Lepidosteus). These ganoids seem to have commenced their
career in the Eocene : and they are represented to-day by
some voracious forms in North American rivers.
TELEOSTEANS Ganoid glory, however, had now quite passed away, owing
to the rapid oncoming of bony fishes. Fishes of this Order
(overwhelmingly predominant at the present time) were
already in a wonderful condition of development in Eocene
seas. To enumerate the various new forms would be to make
a list of some length, and not of general interest. Suffice it
to say that all the Orders and Sub-orders into which existing
bony fishes are generally divided were more or less repre-
sented. The approximation was even closer than this, for
many existing families of the Sub-orders were represented,
and even existing genera of some families. Remains, for
instance, have been found of present-day genera of herrings
and wrasses.

Countless genera, and many families of Eocene fishes
were destined to disappear in course of time ; but, in the
light of present knowledge, it can be said that no fishes were
henceforth to appear with any important modifications of
the skeleton.

EOCENE PERIOD

137

Owing to defects in the geological record fish-life seems
to have suddenly attained a decidedly modern aspect.
" Writ in water " largely applies to fish genealogies. And
indeed practically all life is met with in the Eocene after a
break in its history.

Among the invertebrate marine masses, crabs exhibited crabs
considerable development. Swimming crabs (Portunites),
long-beaked spider-crabs (Oxyrhyncha), sharp-nosed crabs
(Maiuta), and crabs in carapaces shaped like that of the
modern land-crab (Catometopa) were all in evidence. Hermit-
crabs — classed, on account of their long tails, with lobsters —
had also made their appearance (PaguridcB).

A remnant of Ammonites lived on, but their annals soon cephalopods
closed. Belemnites were represented only by a few forms
with the internal shell much reduced in size. Some of them
seem to have been becoming very much like the ordinary
sepia or cuttle-fish of our own times (Belosepia). Others
resembled those modern cuttle-fishes in which the shell has
almost disappeared (Spirula). Nautili continued prosperous,
and were thus restored, after a long eclipse, to a position of
importance among cephalopods.

Gastropods were assuming a modern aspect. Siphoned univalved
forms, which had been improving their position ever since MOLLUSCS
the Trias, were now the prevailing type — whelks (Buccinum),
cowries (CyprcBd), mitre-shells (Mitrd), and olive-shells
(piiva) being in great force. Some forms were living in
turreted shells half a yard in length (Ceritheum). Old-
fashioned siphonless sea-snails, although relatively quite
unimportant, were well represented by some old genera that
had held on from the Trias (Natica, etc.).

Chitons were now of modern type, with the shell plates
well attached to the margin of the mantle (IschnochitonidcB).

Many genera of bivalved molluscs had now been super- bivalved
seded by modified forms. Existing genera of mussels {Ano- molluscs
donta), sponge-borers (F^//se//a), and various burrowing bivalves
had become distinct (Cytherea, etc.) : and clams approximated
much more to living forms (Byssocardium, Lithocardium).

Lampshells, so far at least as regards reduction of families, lampshells
;now rested on the bed-rock of their depression.

138

EVOLUTION IN THE PAST

POLYZOANS Of polyzoans it may be remarked that the highly organised
colonies with zooids in lidded tubes, and with a depressed
class of slave-zooids (Cheilostomata), now far surpassed the
once dominant lidless colonies (Cydostomata). The latter
showed no sign of changing their democratic character.

SEA-URCHINS Sea-urchins were not so diversified as in the last Period ;

but bilateral forms with the mouth well brought forward
were becoming predominant ; and some present-day genera
SEA-LILIES were beginning to appear (Hemiaster, etc.). Crinoids seem
once again to have been " minished and brought low."
CORALS Corals for the most part closely resembled some of the
forms now living. Solitary corals of existing genera were
numerous (Turhinolia, etc.). Reef-building was chiefly being
carried on by the Porites — a genus still prominent in coral
life. Of Madrepora corals — the most important of the reef-
builders at the present time — there is no evidence.

PROTOZOANS Perhaps the most remarkable feature of Eocene invertebrate
life was to be found in the lowest division — the protozoans.
The wonderful amount of rock-building done in Cretaceous
times by these individually insignificant creatures has already
been referred to ; and the part played by them in the Eocene
was no less astonishing. On a great part of northern France,
then submerged, countless millions of foraminifers lived and
died {Miliola, etc.). In course of time their accumulated
shells resulted in the formation of thick layers of rock, now
known as Miolitic limestone. In modern times recourse has
been made to this vast and closely packed protozoan cemetery
for the building of many stately mansions.

Another family of protozoans was in innumerable force
in the Mediterranean — a much larger sea then than now.
These rock-builders, on account of the coin-like form of their
shells, have been named Nummulites. They varied in
dimension from minute size up to that of a crown piece ; and
their shelly wealth is now known as nummuhtic limestone.
Eocene nummulites are commemorated in the Pyramids,,
and also in mountains. The Pyrenees, Alps, Carpathians, and
Himalayas are all largely composed, even at their highest levels,
of nummulitic remains. Those lofty ranges, therefore, cannot
have been raised above sea-level before the Eocene Period.

EOCENE PERIOD

139

The Eocene world no doubt contained a great deal of
vaguely developed and highly composite life ; but it pos-
sessed a marine population — vertebrate and invertebrate —
not greatly differing from that of our own times. Quaint
reptile forms — land-dwellers, sea-rovers, and voyagers in the
air — had become extinct ; and reptiles of all existing Orders
and Sub-orders were on the scene. Various birds, comparable
with living forms, were appearing ; and divers mammals
abounded, awaiting indeed differentiation in many cases,
but more or less representative of all existing Orders. Trees
also and shrubs intimately related to growths of our own
time were spreading far and wide. Modern life had dawned.

CAINOZOIC AGE

OLIGOCENE PERIOD

INVERTE- Beyond the fact that it showed a decidedly closer resem-
BRATES blance to that now existing, there is little calHng for remark
as^to the condition of invertebrate life. The gastropods or sea-
snails with the breathing apparatus, initiated in the Trias,
were greatly increasing their predominance over species of
older fashion. In coral life ancestral forms of some very
important reef-builders of the present day made their ap-
pearance (Madrepora). Coin-like nummulites — multitudi-
nous in Eocene times — were now being called in.

There is nothing of particular note to report either about
AMPHIBIANS fishes or reptiles. In amphibian life, the frog fraternity
was diversified by the rise of forms closely related to
the Indian bull-frog (R. tigrina). And small toads — prob-
ably of the green kind — were by this time attesting
the successful development of tailless amphibians (Bufo
viridis).

MARSUPIALS Marsupials were still represented in Europe by opossums
(Didelphys) ; but there is not much evidence as to " pouched "
life in other parts of the world.

The higher mammal life had lost some of its quaint and
primitive features. The variously related Phenacodi had
become extinct ; and Lophiodonts and Palaeotheres — with
afiinities to horses, tapirs, and rhinoceroses — were passing
away, having, as it were, shot their bolts.

ANCYLOPODS But the days of strange beasts were far from being at an
end. Among other such creatures some hyaena-shaped brutes,
toothed like hoofed animals, but with clawed feet, were at
this time enjoying life in parts of Europe and North America

140

OLIGOCENE PERIOD

141

(ChalicotheYiidce). These quaint quadrupeds moved about
with the weight of the body thrown on the outside edge of
the foot, the feet being bent and twisted as in the case of some
existing ant-eaters. They were not forerunners of sloths
and ant-eaters, nor, indeed, of any animals outside their own
peculiar line. The family, however, possessed considerable
staminal qualities : for it did not leave the arena of life
until the early Pliocene.

Ganodonts — notable in the Eocene for edentate pro- edentates
clivities — had quite died out. Certain small creatures
allied to aard-varks and scaly ant-eaters were certainly
appearing in Oligocene times (Palcsorycteropus, Necromanis,
Leptomanis) : but how far ganodonts were responsible for
these cannot be determined.

Among the survivors of strange herbivores of Eocene titano-
times, the rhinoceros-like titanotheres were the most remark- theres
able. The Oligocene forms were of much less benignant
aspect than their Eocene forerunners. The latter were for
the most part unarmed beasts ; a few species only having
horns in faint sign or promise. Of very different aspect were
these later forms. Not only were they of larger size ; but
they had become grim-visaged with paired horns (Brontops).
The horns, certainly, may not have been as serviceable as they
appeared. They were located in the region of the nose — not
a very strong foundation — and were placed, not one in front
of the other as with two-horned rhinoceroses, but trans-
versely. They cannot, therefore, have been equal to great
strains.

Titanotheres, in spite of these structural achievements,
still retained no small power of adaptation ; and in the
course of the Period they received strong calls to justify their
existence. In response to these demands the skull under-
went several modifications, and the horns increased in
length. The teeth also joined in the family effort. After
this display of energy the animals met with some success.
But it was only for a short time ; for long before the close
of the Period they one and all disappeared. They never seem
to have enjoyed an extensive range, for hardly any remains
of them are found outside limited areas in North America.

142 EVOLUTION IN THE PAST

Indeed they appear to have been little more than incidental
expenses incurred by Nature in her efforts in rhinoceros
development.

RHINO- The more truly rhinoceros forms, although in advance of
CEROSES their Eocene forerunners, were as yet in experimental stages.

Some small animals — not so big as Shetland ponies — were
toothed somewhat after the manner of modern rhinoceroses ;
but they had comparatively long necks, and somewhat
resembled ponies in appearance (Hyracodon). They prob-
ably roved in herds about the open country ; and as they
were footed like the early equines, and were somewhat
lightly built, they were doubtless fair gallopers. Fleetness
in flight was indeed of importance, for they were too poorly
equipped to confront formidable foes. They lived chiefly
in North America, and were probably an offshoot of the old
Lophiodont family — so rich in aflinities. Their career was
of no long span. Indeed in the course of the Period they
became extinct — wiped out, probably, by the rapidly in-
creasing carnivores. Possibly they never developed sufficient
speed for the mode of life they had adopted, and their
sentinel system may have been defective. It was never-
theless enterprising of the little creatures to seek to better
themselves by quitting the swamps and thickets of their
forefathers. And their untimely fate excites one's sympathy
even at this distance of time.

Other creatures living in Europe and North America were
more stoutly built, and more nearly resembled modern
rhinoceroses {Cadurcotherium, Metamynodon). They were,
however, hornless ; and they also differed from existing
forms in being over-toothed and over-toed. They differed,
moreover, in habits, for they haunted lakes and rivers. No
trace of these aquatic rhino's has been found after this
Period. It would seem, therefore, they were no more suc-
cessful than their relatives of the plains.

The genius of rhinoceros-life, however, was by no means
defeated. In thickly wooded regions in Europe yet other
forms were living (Aceratherium) ; and these, in the matter
of teeth and toes, were drawing near to rhinoceroses now
living. As the creatures were heavily built and hornless, they

HYkACODON

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OLIGOCENE PERIOD

143

doubtless exercised a wise discretion in living in strict retire-
ment.

At the close of the Eocene, ancestral horses had had their horses
teeth more strongly crowned, enabling them to masticate
a more varied vegetation. They had also increased from
the size of fox-terriers to that of foxes ; and their feet,
although continuing four-toed and three-toed, were more
compact than those of the earlier forms. The record of the
race in Europe in Oligocene times is unfortunately very
imperfect. It is clear, however, that the teeth of the animals,
although still short-crowned, were stouter and stronger than
those of earlier forms (^Anchilophus). From North America
fuller evidence of progress has been obtained. Here, too,
the little creatures were becoming more strongly toothed
(Mesohippus). They were also larger-headed and taller,
attaining in some cases the height of good-sized harriers.
They also exhibited progress in a greater compactness of
the feet, as they were three-toed on the fore as well as on
the hind limbs. The side-toes, no doubt, touched the ground
when the animal was grazing, but they were probably little
more than passengers in the gallop.

Pig-life was progressing, for some forms as large as wild swine
boars (Hyotherium, etc.), and much bigger, therefore, than
the hare-sized creatures of Eocene times, were now grubbing
about in the forests. All the animals seem to have had four
usable toes on each foot, as with the earlier forms ; but the
canine teeth, although not of tusky status, were now well
developed. The creatures were of a composite character,
some of them partly pig, and partly — though to a less degree —
peccary. In some North American forms the pig and peccary
characteristics were in reverse proportion (Perchoerus).

There were also various other pig-like creatures ; but
they were, so to speak, merely players of incidental music
to the main theme. Some fine-looking brutes were among
them, as large as rhinoceroses (Elotherium). These probably
had long given up frequenting boggy lands, for their feet were
more compact than those of modern pigs. Indeed the side-
toes, which would have been of service for resistance in
swamps, had all but disappeared.

144

EVOLUTION IN THE PAST

Other pig-like brutes known as Anthracotheres, and first
in view in the Eocene, became prominent during OHgocene
times. In Europe Hyopotamus was a distinguished genus
of this family, and was represented by many forms. The
skulls of most of these animals were shaped much Hke that
of an opossum ; but some forms, chiefly North American,
had skulls shorter and more pig-Hke. As anthracotheres had
four toes on each foot, and all the toes touched the ground,
they doubtless spent the best part of their time in swampy
regions. Anatomically they were certainly in a somewhat
anomalous condition ; for, to judge by their teeth, they
indulged in cud-chewing. Evidently, therefore, they were not
turning the wheel of pig-evolution ; nor were they more than
in the backwaters of ruminant life.

Primitive ruminants of small size, and deer and gazelle-
like in shape, had made their appearance in the Eocene
(Xiphodon, Anoplotherium) ; and some of their Oligocene
descendants apparently had undergone no modification.
Some forms, however, were now timidly chewing their food
with teeth of a more decidedly ruminant type (Ccenotherium).
These little creatures — they were not as a rule more than a
foot in length — became very numerous in parts of Europe.
They were decidedly of chevrotain character ; and some
indeed were probably identical in form with living chevro-
tains {Prodremotherium, Hycsmoschus).

Creatures of well advanced chevrotain type were also in
some force in North America (Leptomeryx). On that continent
also were some allied forms, long-tailed, and of the size of
sheep. These were not only primitive in respect to the teeth,
but for hoofed animals they were so far old-fashioned as to
have their front feet terminating with five toes (Oreodon).
There were also a few forms of a more decided archaic
character, with the feet clawed instead of hoofed (Agrio-
chcems).

All the ruminants so far referred to were hornless ; but
in North America the males of some allied forms were
elaborately armed (Protoceras). The skull was surmounted
by a pair of small horns ; and a comparatively large pair
adorned the snout ; whilst two good-sized tusks shot down

OLIGOCENE PERIOD

145

from the upper jaw. These animals were, therefore, able to
confront some of their difficulties with their heads, when
their fellow-ruminants had to take to their heels. Doubt-
less too they were busy with their horns in times of court-
ship.

This profusion of horns recalls some stumpy-footed brutes
of the Eocene (Tinoceras), but the resemblance ends there.
Those monsters were elephantine in size, heavy and clumsy,
and deficient in brain power ; whilst these fearsome-headed
animals were not much larger than sheep. They were,
moreover, of graceful deer-like outline, and had exceptionally
well-developed brains. Among living animals chevrotains,
deer, and giraffes all hold some affinities with them. They
were, therefore, of a comprehensive, patriarchal type.
But they were as patriarchs that had lost their fire ; for
in the Oligocene they were not on the active list of Evo-
lution.

Meanwhile out of the still tangled mammal life some deer deer
of primitive form had emerged. The largest of these did
not stand more than two feet in height — the height of the
Musk deer ; and they probably closely resembled that
animal in appearance {Dremotherium, Amphitragulns). They
were all hornless, and probably took to flight on the first sign
of danger. Some of them, indeed, had long canine teeth,
which may have proved useful in a struggle : but the fortunes
of cervine life, and indeed of all more or less defenceless
mammals, must for a time have trembled in the balance.

Ruminants were also gaining importance by camel-like camels
developments. Whilst some Eocene ruminants of this type
were only about the size of pug-dogs, Oligocene forms were at
least as large as good-sized poodles {Poebr other ium). In
form they probably resembled the Lama, and their harmless
aspect added another peaceful feature to the fauna. Indeed
with the horned titanotheres dismissed from the scene early
in the Period, with boars untusked, with rhinoceroses, and
practically all the ruminants, hornless, it looked as if a
reign of peace might arise in the mammal world. But the
sign was only surface deep ; and carnivores, moreover, were
a standing menace to a millennium.

146

EVOLUTION IN THE PAST

Carnivores in some cases were becoming quicker-paced,
and more deadly in dentition. Faster movement, no doubt,
had been necessitated by the increased fleetness of herbivores.
Mental developments were, doubtless, also going on in both
ranks. Herbivores had long been victimised ; and as a
consequence their faculties of observation must have become
sharpened, and the bump of caution developed. This mental
evolution, it may be supposed, was being matched on the
part of the carnivores by an increased cunning. On both
sides, therefore, the mental standard was being raised.

It is clear, however, that carnivorous brutes of primitive
type (Creodonts) were still able to pick up a living, although
their brains were diminutive, and their dentition not of the
most approved pattern (HycBnodon). These, however, were
now quite unimportant in comparison with the forms with
better brains, and with up-to-date cutting and crushing
teeth. Small animals of this superior stamp, toothed like
dogs, and civet-like in appearance, had, it may be remembered,
come to the fore in late Eocene times (Cynodictis). Descen-
dants of these animals were now very numerous ; and they
were supplemented by forms of wolf-size, and more resembling
dogs in aspect than civets (Cephalogale).

Other forms abroad, flat-footed and with dog-like skuUs,
seem to have been a combination of dogs and bears ; and
they probably represented a stock out of which bears were
ultimately to emerge {Amphicyon).

Some of the Eocene carnivores, although mainly canine
in structure, more resembled cats, no doubt, in some ana-
tomical features. Such-like generalised forms — skulled and
toothed as wolves but tailed like leopards, and possessing
claws that could in part be retracted — were certainly in
existence in this Period (Daphnceus, N.A.). In certain of
the Eocene carnivores, however, the cat must have become,
so to speak, the predominant partner in the body. This may
be inferred from the existence of decidedly cat-like forms in
Oligocene times. The latter animals, moreover, were evident
on two lines of evolution, that had issued, no doubt, from
a common stock. Some of them were slenderly limbed, and
fleet of foot ; and their upper canines were so far developed

OLIGOCENE PERIOD

147

as to earn them the name of " sabre-toothed " cats (Machae- " sabre-
rodonts : Mlurictis, Dinidis, Nimravus). Other forms were tooths"
heavily built (Hoplophoneus, Eusmilus), and possessed extra-
ordinarily big upper canines, finely indented along the edges.
Against these terrible weapons not even the thickest-hided
of the herbivores can have been invulnerable. The animals,
it may be supposed, were not fleet runners, and in order to
get to close quarters with their prey, they must frequently
have had to exercise considerable stealth.

In Oligocene times some of the " sabre-tooths " attained
the size of hyaenas and jaguars. Some of their descendants,
as will be noted hereafter, were much bigger animals ; and
there were not many lands which " sabre-tooths " failed to
explore.

Civets had been more or less distinctly foreshadowed in civets
some of the Eocene carnivores (Proviverra) ; and in the
Oligocene Period some of their descendants apparently were
identical in form with living civets (Viverra). This early
appearance of civets in, so to say, a completed condition is
remarkable. Mammal life, as a whole, was destined to
undergo many modifications, and to experience in some of its
departures absolute extinction. Civets, amid surrounding
change and decay, were to hold their own without practically
having to adopt any structural reforms.

Other animals, although still closely allied to the civets, weasels
had really dissolved partnership with them, and were develop-
ing into weasels. Animals of this type, however, were to
undergo important modifications ; for these Oligocene
pioneers differed in tooth and skull from existing weasels,
and in some cases were longer in the limb {Plesictis, Palceo-
prionodon, Stenoplesictis, etc.). Yet other civet allies were otters
diverging, and in no uncertain manner, in the direction of
otters {Potamoiherium).

The otter-like and weasel-like creatures were sufficiently
differentiated from the family to which the civets belonged
(ViverndcB) to constitute a new carnivore family (MustelidcB).
Their principal diet consisted probably of fishes, birds, and
small reptiles ; but their presence was doubtless felt among
mammals of a humble character.

148

EVOLUTION IN THE PAST

Carnivores were thus present in great variety ; and the
environment of the gentler animals was alive with dangers.
Some part, however, of carnivore ferocity found outlets in
its own ranks, for the animals no doubt preyed to a certain
extent on one another. Their mode of Ufe, moreover, was
conducive to internal dissensions ; and wild beasts do not
settle their differences by arbitration.
RODENTS Rodents — which may have fallen frequent victims to
incipient weasels and otters — had now spread far and wide.
Many changes had been wrought in their ranks, and the
highly intermixed condition of development, which had
characterised their Eocene forerunners, was now a thing of
the past. Unlike their predecessors — and like modern
rodents — they were without canine teeth ; and compensa-
tion had come by the development of very powerful incisors,
thoroughly adapted to gnawing purposes. The animals,
moreover, were branching out in various directions. Some of
them were practically indistinguishable from living squirrels
(Sciurus). Other forms, though closely linked with squirrels,
seem to have been developing in the direction of cavies and
porcupines (Sciuroides, Ischyromys). In yet other forms a
beaver proclivity was decidedly marked (Steneo fiber). And
rats (Eumys, Cricetodon), dormice (Myoxus), hares and rabbits
(PalcBolagus, Titanomys), all more or less of modern aspect,
were by this time in existence.
INSECTIVORES Insectivores, i.e. mammals with their teeth specially
adapted to an insect diet, were in evidence in Eocene times
in certain shrew-like forms, that had been foreshadowed as
far back as the Jurassic Period. From insectivorous creatures,
more or less of this humble description, some higher forms of
life had no doubt arisen ; but developments continued more
or less on the old lines. It is clear from the condition of the
Oligocene insectivores that consequent, it may be supposed,,
on some enforced changes of habit, important modifications
had taken place. Some of the animals had taken to living
underground, and were in fact moles, though their limbs
were not so well adapted for burrowing as in the case of
living forms (Protalpa). Others seem to have been in a
hesitating condition between moles and hedgehogs (Tetracus) ;

OLIGOCENE PERIOD

149

whilst some had so far advanced as to be real hedgehogs,
although they differed in some minor points from modern
forms (PalcBoerinaceus). Creatures almost shrews, and also
completed shrews, were now abroad (Amphisorex, Sorex),
and in some cases probably were adopting aquatic habits.

Thus underground, on the ground, and probably in the
water was this ancient line of life grappling with the problems
of existence.

It is supposed by many that from the ancestral stock of primates
these various insectivores certain forms must have diverged,
in times prior to the Eocene, and given rise to the Order of
Primates. As early mammal life was so much intermixed,
the question of the origin of particular groups is beset with
difficulties ; but it is certain that some of the Eocene
lemurs or half-monkeys held strong affinities with the insect-
eaters.

The Primate Order was represented in the earliest Eocene
by some vaguely defined lemur-like animals ; and as the
Period advanced some animals more closely resembhng
lemurs made their appearance. In Oligocene times animals
were in being that, in regard to the number of teeth and the
shape of the skull, still more resembled lemurs as now known
{Necrolemur).

Certain of the Eocene lemuroids seem to have been develop-
ing in the direction of apes (Adapts) ; and animals identical
in form with these were living in Oligocene times ; but no
remains of more advanced primates have been discovered.
Animals which have been referred to the apes were living in
European forests ; but they seem to have had quite as close
affinities with pigs as with apes, and they were probably
a disappearing race (Cebo cheer us). Some interesting primates
were living in Africa in late Eocene times, but their de-
scendants of the Oligocene have not yet been brought to
light.

Before leaving the mammals notice must be taken of WHALES
certain creatures whose far-back ancestors had quitted the
land for a seafaring life. Before the close of the Eocene
some whale-like forms, known as Zeuglodonts, were exploring
the seas in many parts of the world. Descendants of these

150

EVOLUTION IN THE PAST

were living in the Oligocene Period, but, so far as is known,
they were in a decadent condition. New forms, however,
were abroad that in respect of the skull were certainly nearer
to the whales of our own time (Squalodon). They were in fact
true whales ; but the family is now quite extinct (Squalo-
dontidcB).

SIRENIANS Sea-cows closely resembhng manatees were off the Oligo-
cene coasts (Halitherium). They, however, still retained
well-defined vestiges of hind-limbs, and differed, therefore,
in this respect from living forms. The latter also present a
difference in being more numerously toothed ; prolonged life
in the seas having, in their case, proved conducive to tooth
multiplication.

BIRDS Bird-life comes before us in the Oligocene shorn of much
antique character, and reinforced by many new forms.
Compound creatures, awaiting differentiations — or extinc-
tion— were, no doubt, still in existence ; but most of the birds
known to be then living resembled more or less closely some
of the present-day forms. It must, however, be admitted
that the annals of bird-life have not been well kept by the
rocks ; and many kinds of birds must have lived and died of
which absolutely nothing is known.

The best evidence of Oligocene birds has been obtained
from strata in France ; and it is clear that a variety of birds
disported in the waters of that region. Some were of compo-
site character, and were probably on the Une of descent to
modern grebes and divers (Colymboides). Others, related
to the albatross-like forms of the Eocene, closely resembled
the sea-skimming shearwaters of to-day (Pu-ffinus). Solan
geese quite of modem type were plunging after prey (Sula).
Cormorants — vaguely in promise in Cretaceous times — were
now completely evolved (Phalacrocorax) ; and gulls, much
resembling living forms, were also on the wing (Lams).
Pelicans and big, quaint birds with affinities to gannets and
pelicans were fish-hunting in the shallows (Pelacanus,
Pelagornis). Ibises and flamingoes of modern genera had
now taken the place of their less sharply defined Eocene
ancestors (Ihis, PhcBnicopterus). But some flamingo-like birds
with very mixed affinities were here and there — presumably

OLIGOCENE PERIOD

on their last legs — competing with the waders of more up-
to-date structure (PalcBolodus). Rails had been for some
time in existence ; and cranes — represented by primitive
forms in the Eocene — were now much as their modern
brethren.

Redshanks (Totanus), stilts (Himantopus) and other birds
of plover relationship (Camascelus) haunted seaside and
inland swamps and marshes. Here too were primitive ducks
grubbing and quacking {Anas).

Over grassy and sandy plains bustards were to be seen
and sandgrouse (Otis, Pterocles). Partridges also were abroad,
rid of strong affinities with turkeys and guinea-fowl {PalcBo-
perdix). Pheasants running about the woods attested another
divergence from a long-confused game fraternity (Phasianus).
Parrots, of unknown origin, were holding discourse in leafy re-
treats (Psittacus), and the notes of pigeon were also to be heard
(Columba). The sylvan scenes were further enlivened by
hoopoes, trogons, and crossbills (Limnatornis, Trogon, Loxia).
Woodpeckers — already distinguishable in the Eocene — had
become modernised : and crows and shrikes had emerged
from some unknown prior states of mixed affinities (Corvus,
Lanius). New songsters too had appeared : and thrushes
and finches were adding their notes to the music of the
woods.

Their music, it is to be feared, did little to soothe the
savage breasts of the birds of prey. Various forms of these
disturbers of the peace were certainly on the scene. Not
only were birds abroad well advanced to becoming eagles
(Palceohierax), but true eagles were also on the wing (Aquild).
Kites, too, were about (Milvus), and buzzards (Buteo).
Whilst these various feathery cannibals carried on, it may be
supposed, their depredations in the daylight, no little
destruction was doubtless caused in the " stilly hours " by
the owls. These nocturnal hunters were more varied than in
Eocene times, and included forerunners of the Screeching Owl
(Strix). Secretary vultures were also in existence (Serpen-
tarius). These may have preferred reptiles and insects to
other means of regalement.

The remains of vast numbers of Oligocene insects have

152

EVOLUTION IN THE PAST

been brought to light ; and insect-eating birds, and other
animals with like tastes, certainly had a variety of victims
at their mercy. Many of the insects have been found en-
tombed in amber cast ashore by the Baltic waves. As amber
is the fossilised gum of certain pine trees, the httle animals
evidently got caught in the liquid resin, and were unable to
extricate themselves. Much additional evidence of an
abundant and varied insect-life has been found in other parts
of Europe, and in the State of Colorado, U.S.A.

At the close of the Cretaceous Period all the Orders into
which insects are now divided were to a certain extent
represented ; unless indeed thrips — first known in the Oligo-
cene — are regarded as a separate Order. The Oligocene
record brings out the fact that in some of these Orders there
had been a great branching out into famiUes. Among the
" straight-winged " insects (Orthoptera) forms had appeared
of " praying " insects — so called from the devotional attitude
they occasionally assume {Mantidce). Saw-flies (Tenthredi-
nidce), gall-flies (Cynipidce), wasps (Vespa), hornets (V.
crahroniformis), and new forms of bees — apparently honey-
bees {Apis proava) and bumble-bees (Bombus) — diversified
the ranks of the " membrane- winged " Order (Hymen opt era).
The " sheath- winged " Order (Coleoptera) was reinforced
by tiger-beetles (Cicindelidce), stag-beetles (Lucanidce), pill-
beetles (Byrrhidce), and blister-beetles (CantharidcB). In the
" double- winged " Order (Dipt era) gad-flies and bot-flies had
now arisen, much to the annoyance, no doubt, of the mammals
{TahanidcB, CEstridce) ; but they were doubtless held in check
by spiders, which at this time were exceedingly numerous.
In the scale-winged Order (Lepidoptera) new forms of moths
were on the wing, including hawk-moths (Sphingidce) and
violet-moths {Noctuidce). Butterflies also were here and
there fluttering about. These greeted guests of the flowers
seem to have been allied to the " blues," " meadow
browns," and " tortoise-sheUs " of our own day {Lyccenidce,
Saty rites, Nimphalides).

The vegetation in Europe was of much the same character
as in the Eocene, indicating a continuance of high tempera-
ture. Palm trees were flourishing on the northlands of

OLIGOCENE PERIOD

153

Germany ; and tree-ferns, ebony, olive, jujube, dragon trees,
and big-leaved arums were luxuriating in scenes where to-
day they would perish with cold.

In North America the heat must have declined, as palms
were being driven from many of their old haunts, and
hardier growths, such as conifers, grasses, and deciduous
trees, were spreading over the forsaken sites.

CAINOZOIC AGE

MIOCENE PERIOD

VEGETATION The high temperature continued in Europe for some time
during this Period, and the central lands of the continent
remained rich with sub-tropical vegetation. Meanwhile the
hardier growths had pressed far to the north. Conifers,
poplars, hazels, oaks, limes, walnuts and various other trees
were now thriving in Spitzbergen, North Greenland, and
other lands within the arctic circle. Some indeed were weU
within 600 miles of the pole.

In the course of the Period, some decline of the European
temperature took place, for palms began to languish ; and
conifers, grasses, and various deciduous trees reoccupied
portions of their lost southern territory. The reduction in
the heat, however, cannot have been very great ; for
camphor and cinnamon trees continued in abundance ; and
palms, though greatly reduced in number, were not entirely
suppressed.

Remains of several familiar flowering plants have been
found in Miocene strata. Irises, pinks, clematis, poppies,
violets, and roses were here and there in bloom. Heather was
spreading over highland scenes. And plum trees, almond
trees, and pineapple plants were ripening their fruit in the
Miocene sunshine.

PRIMATES Bright and bounteous though the landscapes must have
been, and congenial the clime, lemurs or half-monkeys seem
to have deserted Europe at the beginning of the Period. The
Primate Order, however, came to be represented on the
continent by creatures of higher stamp. There had, indeed,
been promise of such in former times, although the evidence
is scanty enough. It is certain, however, that in the course

1 54

PLIOPITHECUS
Remains found in the Miocene of Sansan, Gers, France

[To face fagt 154

MIOCENE PERIOD

155

of this Period monkeys and apes existed in Europe in more
than shadowy outUnes. These creatures, however, had not
so far developed as to resemble closely any existing members
of the Order. They were, rather, combinations of forms
which now are quite distinct. Some of them seem to have
been a blend or composition of baboons and anthropoid apes
(Oreopithecus) : others to have been a combination of existing
genera of the latter, Dryopithecus, for instance, was in part
a chimpanzee, in part a gorilla. Some forms, however, seem
to have been so far developed as to approach very closely the
gibbon apes of our time (Pliopithecus).

Primates, compelled in the first instance to take to trees
for safety, had probably long before this time become more
or less permanently arboreal in habit. It was not a dignified
mode of life for the highest order of mammals. But the
creatures were, by nature, not well off for weapons ; and
they had not the wit to manufacture them. Possibly they
had not even become so far civilised as to practise the art of
throwing sticks and stones.

At this time, however, some of the animals probably did
not confine themselves to arboreal life. Indeed, by means of
their long arms, and occasional adventitious aid, they may
have pedestrianised in a fairly erect manner.

Insectivores — near relatives of the primates — were now insectivores
of little importance. The adaptabilities of these animals,
however, were great, as attested in the Oligocene by burrow-
ing moles, shrews of aquatic habits, and hedgehogs. The
Miocene yields evidence that yet another mode of living had
been resorted to, as some of the animals had taken to
haunting trees (Lantanotherium). It only remained for in-
sectivores to fly ; and it is interesting to note that the now
living " flying lemur " (Galeopitheais) seems really to belong
to the Insectivore Order.

Some developments had taken place among the rodents, rodents
Porcupines, not clearly distinguishable in the Oligocene from
squirrels, had now so far diverged as to form a distinct family
(Hystricidce) ; and beavers, " half -create " — to use a poet's
phrase — in the last Period, were now completely evolved
(Castor).

156

EVOLUTION IN THE PAST

Some of the rodents in North America were intermediate
in structure between squirrels and beavers, and were re-
markable for having a horn on the snout (Mylagaulus). As
they were of burrowing habits, the implement may have con-
siderably expedited their work underground.

Cat-dogs were still in existence in North America
{DaphcBfius, Daphcanodon), but became extinct before the
close of the Period. Other old-fashioned flesh-eaters were
also fast dying out in North America and in Europe
{Hycenodon) ; and on both continents the butcher element
was represented almost entirely by carnivores of later
type.

Among the weasel-like animals some forms had now
become specialised as martens (Mustela), and polecats (M.
putorius). Otters also had an estabhshed identity {Enhydra) ;
and before the close of the Period some seem to have been
of modern type (Lutra). Some true cats, suggestive of an
animal between a leopard and a polecat, were also appearing
(PseudcBlurus) ; and a few forms were toothed as modern
cats (Felis). The lightly built " sabre-tooths " were now
extinct (Dinictis, etc.) ; but it was probably from them that
the cats of higher grade had been derived. The new forms,
however, were not the champion felines of the time, for the
heavily built " sabre-tooths " had gone on from strength to
strength, and were now, moreover, in great force (Machce-
rodus). Whilst these and the newer cat-forms probably pre-
ferred to attack prey " sitting," other carnivores exulted in
the joys of the chase. Horses, deer, and other herbivores
were doubtless pursued over the grassy plains and up the
hillsides by wolf-like animals (Dinocyon) ; and foxes — by
this time more or less clearly defined — no doubt joined
eagerly in the hunt (C. (Eningensis).

Bears were also abroad. Such animals had in Ohgocene
times been looming in forms with well-marked canine points
in their anatomy (Amphicyon) ; and similarly compounded
animals lived through a portion of the Miocene. Some aUied
forms, however, had now so far swamped their canine
affinities as to be describable as bears (Hycenardos) ; whilst
a few creatures seem to have been true bears — the dog

MIOCENE PERIOD

157

quartering, so to speak, having been removed from the family
escutcheon (Ursavus). The habits of these various animals
were probably much as those of bears now living. At any
rate, they were too heavily built and too flat of foot to be
successful in the chase. The same may be said of certain
North American forms which at this time were developing
into raccoons {Leptarctus). The latter animals, indeed, may
have subsisted chiefly on fish.

Some extinctions and many developments had taken place
among plant-eating animals. Old families from which tapirs,
horses, and rhinoceroses had been derived, had passed away
(LophiodontidcB , PalcBotheriidce). And a like fate had over-
taken xiphodonts, and other forerunners of ruminants
(Anoplotheria).

Rhinoceroses were now represented by forms old and rhino-
new. Old-fashioned hornless brutes were still living in ceroses
Europe and in North Ameiics. {Acer atherium). On the latter
continent these animals were now supplemented by a few
creatures, whose snouts exhibited some promise of being
supplied with horns {Dicer atherium). The descendant forms,
however, were never endowed with those weapons ; and
rhinoceroses, as developed in America, proved too innocuous
for survival. Very different was the fortune of the family in
the old world. Here many of the animals had well-weaponed
snouts (R. sansaniensis) ; and thus armed were able to face
the course of events, whilst their hornless relatives dwindled
to extinction.

Deer — hornless in the last Period — were now being equipped deer
for combat (Dicroceros elegans). The antlers were not as yet
of an elaborate kind, as the shaft or beam never seems to
have borne more than one tine. The shafts were supported
on good-sized, bony pedicles ; and the appearance of the
armature must have been very much as that of the Muntjac
deer now hving in Asia. The appendages, it is clear, were
not permanent like the horns of the rhinoceroses, but were
shed and renewed periodically as in the case of modern deer.

The four-horned, deer-like animals of the Oligocene (Proto-
ceras) were now represented by a few vanishing forms
{Syndyoceras). The horns had become so big and mutually

158

EVOLUTION IN THE PAST

interfering as to be — except in appearance — quite ineffective.
The race, it is clear, was suffering from old age and conse-
quential eccentricities; and at the close of the Period it
returned to "the friendly elements,"
ANTELOPE In North America some of the ruminants were develop-
ing into antelopes {Cosoryx), some into mule and other deer
(Blastomeryx). In Europe a few small short-horned creatures
were not far short of being true antelopes (Protragoceras).
SHEEP And — ^probably from the same parent stock — some primi-
tive forms of sheep were now appearing (Criothermm).
CAMELS Camels certainly were becoming of nobler stature than
their poodle-sized forerunners. In North America — where
camel-life seems to have originated — animals were now to be
seen nearly as big as modern camels, although of somewhat
lighter build (Procamelus). Whether they were humped or
not, it is impossible to say. Masses of fat, if ever they did
rise on the back, must long ago have been demohshed by
Time, if not by quicker consumers. The backbone, it may be
mentioned, affords no information as to hump-building ; for
its outline would not have been affected by fatty super-
structure.

The cervical vertebrae of some of these forms (Alticamelus)
had become greatly elongated, resulting in a giraffe-hke neck.
The legs had also been lengthened ; and the hind-limbs were
longer than those of a giraffe. The animals could thus feed
on foliage out of the reach of most members of the family.
The adaptations were, of course, advantageous to animals
in lands where low-growing vegetation was scarce or un-
inviting. To judge from the size of the brain-case, these crea-
tures were far less intelligent than existing camels — which
places their mental calibre very low. There is no evidence of
the survival of the race in the next Period.

Giraffes, so far as evidence goes, had not yet appeared.
It is not, however, supposed that these long-necked camels
were on the Line to Giraffe evolution. It is well known that
animals of different groups occasionally develop similar struc-
tures under the stress of similar conditions.
LAMAS Some of the camel-like animals, it is clear, were develop-
ing into lamas (Pliauchenid). This humpless, and almost

ALTECAMELUS
A girafife-caniel Remains found in Miocene of Colorado, U.S.A.

[To face page 15S

MIOCENE PERIOD

159

tailless branch of the family migrated in later times to South
America, and there attained considerable prosperity.

Horses had increased in stature. Some as large as good- horses
sized Shetland ponies were now succeeding the harrier-sized
creatures of the last Period. The North American forms
probably were capable of much greater speed than their
predecessors, as their " extra " toes, though still in evidence,
were quite off the ground (Protohippus, Neohipparion). The
European forms do not seem to have attained the same com-
pactness of foot {Anchitherium) ; nor were their teeth so
strongly crowned as those of their American relations.

At the same time there were horses in North America with
well-developed and usable side-toes (Hyohippus). These
creatures probably frequented swampy regions, where well-
splayed feet must have been of advantage. Their teeth,
moreover, were of an old-fashioned, weakly crowned type —
more fitted for marsh vegetation than for the hard grasses of
the plains.

Pigs with their partiality for miry places were, like the swine
last-named horses, keeping their " extra " toes in a usable
condition. It is probable, however, that at this time the
main weight of the body was being thrown on the two inner
toes of the four. Some of these marsh-dwellers were becoming
more decided pigs as regards the shape of the skull (Lis-
triodon) ; but in some respects their dentition was rather that
of tapirs than of pigs ; and, at best, they were uncanonical
pigs. The most modern-like forms on European scenes were
some diminutive creatures (Sus chceroides) that must have
closely resembled little pigs that now haunt the forests of the
Andaman Islands. And as they embraced the essential
articles of pig anatomy, they may be spoken of as orthodox
pigs.

Like rhinoceroses, pigs in North America never made much
progress ; and it was reserved for the old world to bring
porcine life into importance. The highest forms in America
in Miocene times seem to have developed into peccaries ; and
swine of higher stamp than peccaries were not destined to
explore the forests of that continent. Big, two-toed pig-
like brutes, such as were in evidence in the last Period, were

i6o EVOLUTION IN THE PAST

still living in America and in Europe (Elotherium). But these
were distinctly heretical pigs ; and towards the close of the
Period they were roasted, one and all, in the inquisition-fires
of Natural Selection.

Animals of far more lordly appearance than pigs were now
in European forests, for thither had elephant-Hke creatures
found their way. It is interesting again to meet this form
of Hfe, as its fortunes during the Ohgocene are unknown —
unless certain strata of doubtful age in the Vienna
basin are to be referred to that Period. It seems safer, on
the whole, to refer those deposits to the Miocene ; and
elephant-hfe thus reappears after a somewhat long break in its
history.

It will be remembered that towards the close of the
Eocene Period this branch of life was represented by some
small, marsh-dwelling forms (Mcdritherium), and also by
some medium-sized and more truly elephant-hke creatures
(PalcBomastodon). A notable feature of the latter was the
lengthened lower jaw, one of the purposes of which was to
afford support for the trunk in process of development. This
elongation of the mandible must have continued during the
Oligocene, for some European elephants of Miocene times
possessed under-jaws of enormous length (Tetrahelodon).
This, coupled with the fact that like their forerunners the
animals were rather long-necked, shows that it was possible for
the animal when standing to get its mouth to the ground.
The trunk had doubtless become longer, and had increased
in grasping power, but it was not, it may be supposed,
sufficiently developed to render the projecting lower jaw un-
necessary. At this stage, however, the trunk and the long
mandible must have been getting somewhat in each other's
way. And if one was to go, it was clearly the elongated chin,
which had served chiefly as a scaffolding.

These animals stood rather over six feet, and were there-
fore about the size of the larger forms of earlier times. They,
however, more closely resembled modern elephants in the
shape of the skull. The tusks, moreover, excepting that they
were partly enamelled, were of modern type.

Elephants, as now known, were not yet in existence.

TETRABELODON
Restored from skeleton found in the Miocene of Sansan, France

[To face page 160

MIOCENE PERIOD

i6i

They were still in the making ; and in the process some
curious brutes had incidentally appeared, as had Titano-
theres in the gradual evolving of rhinoceros life. These
elephantine by-products are known as Dinotheres. They had
long sloping faces, much unhke those of modern elephants ;
and they possessed also elongated lower jaws. This jaw,
instead of shooting straight out, had a strong downward
curve, as if the trunk no longer required its support. The
upper jaw seems to have been tuskless, but the bent chin
terminated with a pair of powerful sabre-shaped " ivories."
The animals doubtless used these implements in self-defence,
and also industrially, such as for rooting up plants ; and in
times of drought they may have employed them in turning
over big stones in dried-up river-beds, in hopes of finding
water.

Dinotheres wandered about Europe, Africa, and Asia in
this and part of the succeeding Period. So far as is known
they never found their way to America. The straight-chinned
forms, on the other hand, discovered North America at the
close of this Period (Tetrabelodon). They had probably
travelled from Asia by means of a land connection existing
on or near the site of Behring Strait.

South America was not at this time connected with the south
northern continent, and its mammal life was for the most America
part of a peculiar and sleepy character. Sloths, armadillos,
and such-like unenterprising animals here held an important
position. They were, moreover, far from their zenith ; for
in later times, as will be seen, they developed to an astonish-
ing extent.

Ground-sloths abounded in a variety of forms ; but their ground-
anatomical differences were naturally not so marked as sloths
were those of later species. The nearer the source the greater
the resemblance. Many of them were quite diminutive
creatures — mere pigmies in comparison with later forms ; nor
do they seem to have walked so much on the outer side of
the feet as did succeeding ground-sloths. Some large forms
were also abroad — five feet and more in length ; and by
raising themselves on their hind-limbs they must have been
able to get the pick of the foliage {Hapahps). Many of the

EVOLUTION IN THE PAST

Miocene species of ground-sloths failed to survive the Period ;
but it is probable that some of those of which remains have
been found (Prepotherium, Nematherium, Analcitherium) were
forerunners, if not actual ancestors, of some of the gigantic
ground-sloths of later times.
ARMADILLOS Armadillos of various types were about the land. Some
were very small animals (Prozaedius) \ others (Stegotherium,
Proeutatus) attained a length of two feet, and therefore nearly
rivalled in size the largest of armadillos now living. They
probably differed but little in appearance from existing forms ;
and like the latter their carapaces had movable bands,
enabling the animals more or less to roll themselves up for
protection,

GLYPTODONTS Other forms, closely allied to the armadillos, are known on
account of their " carved " or fluted teeth as Glyptodonts.
They differed in some parts of their anatomy from armadillos,
and were not, Uke the latter, adapted for burrowing. Their
carapaces, moreover, were far less flexible. Except in a
few cases they did not exceed the biggest of the armadillos
in length, great though be the disparity in nomenclature
(PropalcBohoplophorus). Glyptodonts were destined to make
a mark in South American mammal Hfe ; and some of the
known Miocene forms (M etopoxotus) probably were ancestors
of the monster glyptodonts that subsequently appeared.

No remains of ant-eaters or tree-sloths have been found ;
but ground-sloths had some strong points of resemblance to
tree-sloths, and also to ant-eaters. Ground-sloths, tree-
sloths, and ant-eaters, therefore, were probably all derived
from a common ancestry. Moreover, it is probable that at
one time there was a still older stock which held potentially
not those animals only, but also armadillos and glypto-
donts.

Many kinds of creatures besides ground-sloths and arma-
dillos were at this time in South America. The most notable
of these were hoofed animals ; but it is not possible to bring
them into close line with any ungulates now living.
TOXODONTS Some of them are grouped together as Toxodonts, as the
typical forms had " bow "-shaped grinding teeth. These
strange animals were for the most part about the size of

MIOCENE PERIOD

163

sheep, with an outward appearance of coneys grown to
gigantic dimensions (Nesodon).

Other allied forms have been named Astrapotheres, or astrapo-
" lightning-beasts " ; and they must have presented a start- theres
ling appearance. They were as large as rhinoceroses ; and,
though not related to those animals, they probably bore an
outward resemblance to them. Some of the brutes were
provided with a pair of long and powerful tusks in the lower
as well as the upper jaw ; and the tusks were so brought into
contact as to ensure a mutual sharpening. As the monsters
were vegetarians, one may suppose that their well-stropped
blades were chiefly used in quarrels about females.

Here also were other hoofed animals known as Litopterns litopterns
— a name having reference to an anatomical feature of the
heel-bones. They were for the most part long-necked crea-
tures, nearly as big in some cases as lamas, and the majority
of them were not unUke those animals in general appearance
{Oxyodontotherium). Their feet, as a rule, were three-toed,
and all the toes were in use. In some rather short-necked
and somewhat horse-like forms the " extra " toes had be-
come dwarfed and useless (Proterotherium), as was the case
with many of the horses then living on the northern con-
tinent. There is, therefore, no doubt that, in regard to the
feet, these animals and the horses were converging in de-
velopment. Indeed, a few of them were in that respect in
advance of the horses ; for they had quite lost their side-
toes, and were toed, therefore, like the modern horse
(Thoatherium). They were, however, far inferior to the
horses on the neighbouring continent not only as regards
flexibility of limb, but also in tooth-structure and brain-
power.

Yet other animals, known as Typotheres, were perhaps typotheres
the most curious of all (Pachymcus). They were about the
size of hares, and probably looked like guinea-pigs much
overgrown. Mr. Lydekker has shown that they were more or
less closely allied to the Toxodonts, and so belonged to the
hoofed Order. They had, however, by a series of modifica-
tions, converged to the rodent type, as regards teeth and
toes, and also in other respects. The squirrels, hares, and

EVOLUTION IN THE PAST

other rodents that were then in the world had reached their
condition of development quite independently of the hoofed
animals. But here were rival forms that had issued from
the ranks of the ungulates. In other words, creatures were
climbing into the rodent fold by another way. This intru-
sion, as after events proved, was not to be tolerated.

No animals describable as elephants seem to have been
in the fauna. But brutes were here (Pyrotherium) some-
what of the type of the hippopotamus-bears that in other
parts of the world had long since passed away {Amblypoda).

Life in South America was thus developing in a somewhat
peculiar manner ; and a fairly tranquil environment ensured
it a large measure of prosperity. Apparently no true carni-
vores were here to disturb the somnolence of the sloths, and
the long feeding hours of the toxodonts and other quaint
herbivores. Boisterous scenes there doubtless were among
the " lightning-beasts " ; but these, after all, were occa-
sioned by a laudable affection for the fair sex.
CARNIVORES Lovers of meat, however, were in the land (Prothylacinus,
SPARASSO- Borhycena). These long-tailed and somewhat wolf-Uke
DONTS animals, in being dull-witted, were to that extent in harmony
with the prevailing tone. They possessed strong affinities
with marsupials, and are classed as such by some good
authorities. Their powers for scenting prey were exception-
ally well developed ; and some of them seem to have been
adapted to arboreal habits (Cladosictis). Their teeth, it must
be admitted, were not of up-to-date type ; but the animals,
no doubt, fared sumptuously on the sleepy herbivores. Their
feasts — probably indulged in at night — led not infrequently
to squabbles among themselves, and there is evidence that
ugly wounds were inflicted in altercations.
MONKEYS The highest class of the population consisted of feeble-
minded, flat-nosed monkeys of the " howler " type (Homun-
culus). The first comers had probably arrived by chance
from lands north of the existing isthmus, having been carried
across the dividing sea on drifting tree-trunks. Their advent
was, no doubt, much resented by the old quiet-loving resi-
dents.

MARSUPIALS Undoubted marsupials seem to have been limited in

MIOCENE PERIOD

165

variety, consisting chiefly of small opossums (Microhiothenum),
and somewhat phalanger-toothed opossum-rats (PalcBothentes,
CanolestidcB).

Marsupials seem also to have been but scantily represented
on the northern continent. In Europe they had long been
on the decline ; and the opossums of the Ohgocene Period
were, so far as is known, the last of pouched life on that
continent.

In Australia this ancient Order was probably full of vigour
and abounding in a variety of forms, as its development
had not been complicated by mammals of higher type.
Evidence, however, is wanting as to the condition of Miocene
marsupials in that part of the world.

If, as there is every reason to believe, no mammals of whales
higher rank than marsupials were living in Australia, such,
in the form of whales, were flourishing off her coasts. These
were creatures of the newer fashion, such as had come into
view in the last Period {Prosqualodon, Squalodon). The
Zeuglodonts — the earliest known whales — apparently had
now quite died out. During the last Period they had been
dwindling in numbers, and the new divergent forms, more
nearly resembling the toothed whales of to-day, had become
well established. In South American waters some forms of
a still more advanced type were in existence. These may be
described as sperm whales, although they differed from
their present-day descendants in having their teeth ena-
melled, and, moreover, in possessing teeth in the upper as
well as the lower jaw (Physodon). Other forms apparently
were in a condition between toothed whales and whalebone
whales (Argyrocetus) ; and a few seem to have reached a
stage constituting them whales of the latter category {Ceto-
therium). In European waters some members of the " white
whale " genus of the Dolphin family were in evidence (Del-
phinapterus). Here also were whales, some qualifying for
" Bottle-nose," some for " Hump-back " distinction ; but
the special features, it would seem, were not fully developed
until the next Period {Hyperoodon, Megaptera).

The success of the seaward move of some ancient land-
mammals was, it will be admitted, beyond question. Con-

EVOLUTION IN THE PAST

gratulations, though not feasible, were well deserved, for the
animals were insusceptible of any essential modification of
their land-designed machinery for breathing, and for the
bringing forth and suckling of young.

SEALS Other mammals, it is clear, had followed the example of
the whale-ancestors by relinquishing land for a sea hfe. The
exchange of elements in this case had resulted in seals, a
few species of which were now in view (Prophoca). Their
tangled course of descent is quite unknown. Their nearest
relatives in the Miocene were probably the otters.

BIRDS More remarkable than the evolution of seals and whales
from land-mammals was the rise of birds from reptiles, and
their subsequent development into a vast variety of forms.

Deficient though be the record, several glimpses of the
progress have been yielded by Miocene strata.

In river-swamps and fenny solitudes heron quite of modern
type were seeking their miscellaneous food {Ardea). Storks
were much more in line with present-day forms. Some,
indeed, seem to have been of the same genus as the Adjutant
Stork (Leptotilus) ; others were primitive wood-ibises (Tan-
talus). New forms of more or less plover origin had become
specialised as auks, guillemots, and curlew (Alancalla, Uria,
Numenius). Gulls, an earlier offshoot of the stock, probably
consisted at this time of many species.

Turkeys, hardly semi-existent, so far as is known, in the
Eocene, had now become completely evolved in North America
(Meleagris). And plantain-eaters (relatives of parrots) aug-
mented bird-life in Europe, where a genial clime provided
them with bananas and other fruits they loved (Necrornis).
CROCODILES The continuance of a widespread warmth enabled crocodiles
and alligators to thrive in scenes which are now denied
them ; and crocodiles, indistinguishable from long-snouted
forms now confined to the tropics, were haunting European
rivers (Tomistoma).
CHELONIANS Huge tortoises, allied to the Greek Tortoise, were creep-
ing about the inland scenes. Water-haunting forms, known
as alligator terrapins, were in the lakes and tidal waters
(Chelydra) ; and turtles closely allied to the Hawksbills or
tortoise-shell-bearers were also in evidence (Chelone girondica)*

MIOCENE PERIOD

167

Tortoises, turtles, crocodiles, and alligators, however,
seem to have been less rich in species than of old, and prob-
ably in most parts of the world they were in a declining
condition.

Lizards and snakes, on the other hand, were steadily lizards
advancing. Of the former reptiles, in addition to creatures
closely resembling those of earlier times, various new kinds
abounded. Some of these are not identifiable with living
genera ; but spotted or " eyed " lizards, skunk lizards, and
so-called " glass snakes " seem now to have issued from the
more or less hotch-potch condition of old lizard-hfe
(DraccBnasauYus, Locellata, Ophisaurus). Snakes — comprising snakes
hitherto innocuous forms only — were now diversified by
cobras, rattle-snakes, and other purveyors of venom (Naia,
Neurodronicus, Bitis).

Amphibian life had for a long time been on the decline, amphibians
and from once possessing huge warriors had come down to
a humble representation consisting of frogs, toads, newts,
and salamanders. In this Period, however, some revivaUsts
of lost glory appeared in the form of big frogs and sala-
manders. The largest of the frogs were some eight inches
in length. These giants of their kind were probably ancestors
of the venomous horned frogs now living in Brazil (Latonia).
Some of the salamanders attained a length of over three feet
(Cryptohranchus). They were certainly big for salamanders,
but they fell far short of the " roofed-head " giants of Triassic
and still remoter times (Stegocephs). Indeed, the total
length of the largest of them did not equal the skull-length
of some of the old " roofed heads." Nor did they hold any
close relationship with those amphibious monsters. Like
the big frogs, they were not without an elixir of life ; and at
the present day salamanders are to be found in Japanese
waters quite as big as their Miocene forefathers.

Although fishes had in the Eocene attained the main fishes
features of their modern development, numerous new species
had doubtless since arisen in the various famihes. Not very
much is known on this subject, but it may be mentioned
that hammer-headed sharks and thresher sharks were now
in the ranks of the long-established non-bony fishes (Sphyrna,

i68

EVOLUTION IN THE PAST

Alopecias). As regards fresh- water fishes geological history
is extremely slight. From discoveries made in Swiss strata
((Eningen) it is clear that pike, perch, loach, tench, and carp
were all in existence in this Period.
INVERTE- Invertebrate Ufe caUs for little notice. The known mol-
BRATES luscs, as in the last two Periods, consisted mostly of species
of a tropical character ; and a large proportion of them
belonged to species still in existence.

Europe, with its palm trees, apes, elephants, crocodiles,
and turtles — to say nothing of the absence of human beings
— was very different in its life aspects from what it is to-day.
Nor was it geographically the same ; for the Mediterranean
was flowing over many parts of the continent which are
now dry land. The Alps, however, and Carpathians — in the
making of which the Eocene nummulites had played so
important a part — were now well in view above the surface
of the waters.

HIPPARION [Tofa.e/^agc .69

CAINOZOIC AGE

PLIOCENE PERIOD

EARLIER EPOCH

Owing to various earth-movements in the course of this
Period the Mediterranean Sea was gradually forced back,
and the continent of Europe attained a shape and extent not
differing greatly from that of to-day. The climate, although
still of higher temperature than now, was becoming less
warm. Signs of a change were evident towards the close
of the Miocene in the decline of the palms. At the com-
mencement of the PUocene these warmth-loving growths
had almost disappeared ; and the climatic changes were
driving crocodiles from old European haunts. Meanwhile
the lowering of the temperature had stimulated the growth
of deciduous trees ; and grasses, spreading more freely, were
now displayed as rich and extensive pastures.

Herbivorous animals were enjoying the verdant scenes in antelope
vast numbers ; and the antelopes of primitive type were
succeeded by various, though for the most part small forms.
Most of these were of mixed affinities. Some, with spirally
twisted horns, combined kudu and eland features (PalcBorias) :
others, also of twofold character, gave promise of the oryx
and the sable antelope (PalcBoryx) ; whilst certain forms in
some points were decidedly goat-Uke (Tragoceros). Some of
the animals were more specialised, and may be described as
harnessed antelopes. Gazelles, more or less indistinguish-
able from modern forms, had also been launched on their
career (Protragelaphus).

Whilst antelope herds fed and prospered on the grassy giraffes
grounds, other animals browsed on the foliage of the trees.

169

EVOLUTION IN THE PAST

These ruminants are the first known members of the Giraffe
family. A few of them, excepting that they were shorter
Hmbed, seem to have borne a more or less close resemblance
to modern forms (G. attica). Most of them, however, held
strong affinities both with antelope and deer, and were far
from having attained the stately and unique appearance of
modern giraffes. They were much shorter in the neck ; and
the limbs were not only shorter, but of nearly equal length.
Well-developed horns, moreover, crowned the heads of some
of the animals (Samotherium, PalcBotragus). These weapons,
no doubt, were manageable, but as the neck became elon-
gated their efficiency must have been reduced. Indeed, in
some of the longer-necked Pliocene forms, living in Europe,
the horns had become insignificant (Helladotherium). It is
not surprising, therefore, that modern giraffes — extremely
necky animals — possess horns only in vestigial condition. Not
one of the known primitive species seems to have survived the
Phocene Period. But it is an interesting fact that at the
present time animals closely allied to them are Uving in
primeval forests of the Congo. This discovery was made by
the intrepid traveller Sir Harry Johnston in 1901. The
name of " Okapi " has been bestowed on the animals by
Sir E. Ray Lankester, who has no doubt of their relationship
to primitive giraffes. Their outward appearance is certainly
very different from that of other giraffes now Hving, as they
are striped, not spotted ; and, like Pliocene forms, they are
comparatively short in the neck. They Uve, it is stated, in
the deepest recesses of the forests — victimised, it may be
supposed, by civilisation.

HORSES Horses were now to be seen on the plains with more com-
pact feet than the Miocene forms (Hipparion). The " extra "
toes were quite off the ground, and dangled at the sides of
the well-developed central toe as useless appendages. Simi-
larly developed horses were certainly in North America in
Miocene times, so the European animals were only following
in the wake of the American. Horses more highly developed
were living elsewhere in this Period, as will be noted shortly.

TAPIRS Tapirs of the Eocene notably differed from tapirs now
living merely in regard to teeth and toes. As the toe differ-

DIXOTHERIUM

[To fine f'iiKC 171

EARLIER PLIOCENE EPOCH

171

ence had been adjusted in the Miocene, and the tooth dis-
similarity had now disappeared, the animals were practically
indistinguishable from modern tapirs. They were certainly
prosperous in Europe at this time. At the present day their
descendants, like the okapi, lead obscure lives in very limited
areas.

Herds of elephants were still enjoying life in Europe elephants
amid the high grasses and in woodland scenes. They appear
to have been identical in form with those of the last Period —
the four-tusked animals with greatly elongated lower jaws
(Tetrahelodon), and the still quainter creatures with down-
ward-bent chins terminating with sabre-like " ivories "
(Dinotherium). The latter animals were of larger size than
earlier forms ; but, beyond that fact, no European probos-
cideans showed any advance in development. Elephants,
however, had made considerable progress elsewhere, as will
be seen when we reach India.

Rhinoceros-life in Europe presented some fresh phases of rhino-
evolution. The oncoming horned animals were more modern- ceroses
ised, and variously developed. Some of them seem to have
been close-allied to the now living Sumatran species (R.
Schleiermacheri) ; whilst others were intimately related to
the so-called Black Rhinoceros now confined to Africa
(R. pachygnathus). Hornless male rhinoceroses, with a line-
age dating to a remote past, were now on their last legs
(Aceratherium) ; and long before the close of the Period
they became extinct. The only hornless rhinoceroses of the
future were of the gentler sex. If any female rhinoceroses
in early Pliocene times were horned is doubtful. A cry of
" horns for women " certainly came in later times, and was
to a certain extent successful.

Here and there a few hyaena-shaped beasts, with claws bent ancylopods
like a scaly ant-eater's, were grinding grassy food with teeth
much as those of a rhinoceros. These and some fellow-forms
that had found their way to Asia were, no doubt, survivors
and also final representatives of an old family well in view
in the Ohgocene Period (ChalicotheriidcB).

Away on the hills deer of various kinds were roaming, deer
Some of them had antlers simply forked like the modern

172

EVOLUTION IN THE PAST

muntjacs, and were therefore in this respect not in advance
of Miocene deer {Cervulus dicranoceros). Many of them,
however, were antlered more elaborately. Some of these
with three-tined antlers were, no doubt, closely related to
the spotted deer now living in India (C. pardinensis). Others
were abroad with four-tined antlers, of a pattern now quite
unknown (C. ietraceros). However long they lived, deer do
not seem at this time ever to have possessed antlers with
more than four tines or points,
SWINE Other animals belonged to the swine family. This branch
of life ever since it commenced in a small way in Eocene
times had been progressing ; but it was not until the Miocene
that animals appeared describable as true pigs. Those
were all small forms, and were closely allied to the pigs
now living in the Andaman Islands. Several pig-Uke brutes
of much larger size had certainly appeared before then ;
but they were unorthodox in some of their tooth or toe
tenets. In early Pliocene times orthodox pigs of small size
were in some force in the forests ; but the family was now
dignified by pigs of much larger dimensions. Some of these,
although not so well tusked as the Wild Boars of our own
time, were bigger than those animals (5. erymantheus).
They were not, however, so big in the body as some of the
old unorthodox forms, and were feebly tusked in com-
parison.

PRIMATES The most important tenants of the woods were undoubtedly
the apes. Their importance was, of course, mainly morpho-
logical ; for it is not to be supposed that they were
primates in the sense of being chiefs or rulers. Some of the
creatures were anthropoid or man-like apes, but their re-
mains are too fragmentary for more precise identification
(Paidopithex). Others had affinities with the Langurs, or
" Holy Apes " of India, as well as with the Macaque apes,
a species of which now lives at Gibraltar (Mesopithecus) ;
whilst a few, although sanctification was as yet a far-off
event, seem to have been " holy " apes pure and simple
(Semnopithecus).

CARNIVORES Heavily Hmbed " sabre-tooth " cats were still the most
formidable of the carnivores (Machcerodus) ; and new flesh-

EARLIER PLIOCENE EPOCH

173

eaters were now on European scenes in the form of hyaenas.
Some of the latter were of primitive description, retaining
close affinities with civets (Palhyana, Iditherium). But
Nature had produced more than prehminary hysena sketches ;
for some of the animals were not far short of being hyaenas
as now known (LycycBua, HycBnictis). Certain of them,
indeed, seem to have been closely allied to the existing
striped species {H. striata). Whether scavenging was at this
time the family profession, it is difficult to say. There must
have been carrion in plenty, and some of the animals may
have disposed of it, and with no little advantage to public
health.

Bear-life in Europe, so far as is known, consisted only of bears
old-fashioned brutes that either retained strong affinities
with dogs (Simocyon), or in which certain canine features
had not been quite obliterated (HycBnarctos). Some de-
scendants, however, of the true bears of the Miocene may
well have been about the scenes.

A glance must now be taken at early Pliocene life in India. INDIA
This has been rendered possible by extensive discoveries
made in the Siwalik Hills ; and a very interesting picture
is brought in view. The ubiquitous " sabre-toothed " cats carnivores
(Machcerodus) were about the land as might be supposed —
especially as elephants, their favourite prey, were there in
plenty. Various other cats, large and small, abounded.
Some of these seem to have been intermediate in develop-
ment between tigers and jaguars (F. cristata) ; others had
developed into cheetahs or hunting leopards (Cyncelums
hrachygnatha) ; and some small forms had reached the
status of true tigers. Civets were numerous ; and here and
there big forms prowled about, unequalled in size by earher
or later relatives. The Dog family was represented by wolves
and jackals, not differing much from forms now living {Canis
Cautleyi, C. aureus).

Whilst the land was thus haunted by carnivores of a
more or less modern aspect, flesh-eaters of a very ancient
race — extinct in other parts of the world — still lingered on
{HycBonodon). So far as can be gathered, these animals
remained in just the same condition of development as their

174

EVOLUTION IN THE PAST

Eocene ancestors — small-brained, weak-limbed, and with
teeth less efficient than those of true carnivores. Once in
the very front rank of flesh-eating animals, their line had
now sunk into utter insignificance. It was long since they
had enjoyed " uppermost rooms at feasts," and they had
probably by this time come down to subsisting entirely on
carrion. Even in that field of regalement they must have
had keen competitors ; and it is not surprising that during
early Pliocene times their annals came to a close.

Bears with vanishing affinities to dogs and indistinguish-
able from forms in Europe were about the land, but in
dwindling numbers (Hycenarctos). Other forms abroad no
longer laboured under the suspicion of being partially dogs
(Ursus Theohaldi). Indeed, they seem to have been closely
allied to the modern sloth bear.

Badgers were certainly in existence in parts of Asia at
this time ; but from what holes or burrows of the misty
past they had found their way into creation is quite un-
known.

Trunky life was well in view in India in forms new and
old. Here, as in Europe, were quaint but stately brutes,
some with protrusive under-jaws (Tetrabelodon), others with
chins bent and sabre-tusked (Dinotherium). The career,
however, of these old-fashioned types was fast drawing to a
close, and the antiqueness of the animals was accentuated
in India by the presence of various species more advanced
in development. Among these were some imposing brutes
which, on account of the character of their molar teeth,
have received the name of Mastodon, or " nipple tooth "
(M. sivalensis). The molars of these animals were ridged
across the surface much as in the case of modern elephants ;
but the ridges were not so numerous, and the inter-ridgeal
spaces, instead of being filled with cement, were usually
raised up into little knobs or nipples. But it was not merely
in possessing teeth which, by reason of their ridged surfaces,
resembled in character the teeth of modern elephants, that
mastodons were remarkable ; for the long-jawed brutes of
earher appearance had their teeth more or less ridged in
the same manner. Distinguishing features of the new forms

EARLIER PLIOCENE EPOCH

175

consisted of the shortening of the neck (in consequence of
which the animal, when standing, could not get its head to
the ground) ; the great reduction of the scaffolding under-jaw ;
the verticalising of the sloping face ; and the development
of the trunk into a powerful grasping organ, with free play-
in all directions. Mastodons, however, were not elephants
as strictly defined ; for the teeth of elephants, although
ridged, are not " nippled." Mastodons differed also from
true elephants, as did the earlier long-chinned forms, in
having their tusks partly banded with enamel.

In certain districts some of the proboscideans possessed
teeth that had undergone further modifications. The ridges
were sharply defined into gable shapes ; and the name of
" roof tooth " has accordingly been bestowed on these
animals (Stegodon). The bosses or nipples had disappeared ;
and the spaces between the ridges were beginning to be filled
with some of the inner tooth substance known as dentine,
modified into a cement. The teeth thus resembled very
closely those of modern elephants. The tusks, moreover,
were no longer enamelled ; and the animals may fairly be
regarded as having passed out of the Mastodon stage and
become true elephants.

Even these were not the most advanced of the trunked
animals on India's scenes. Other elephants were munching
their food with teeth still more modified {E. planifrons,
Euelephas). Their teeth, in fact, were of a quite modern
character — very deeply ridged, with the interspaces filled
up with cement. The teeth thus had rough though fairly
level surfaces, and were excellently adapted for grinding
purposes. As after events proved, elephants toothed in this
manner were alone destined to survive. Teeth, it need
hardly be said, have been an important factor in mammal
fortunes.

Horses in vast numbers were on the plains and hill-sides.
Most of them were identical in form with those that were
living in Europe at this time — three-toed animals about the
size of Shetland ponies, and with grinding teeth of inferior
construction to those of modern horses (Hipparion). Evolu-
tion, however, in India had proceeded farther ; for animals

176

EVOLUTION IN THE PAST

were in the herds with teeth of modern type, and the " extra "
toes — only dwarfed in other forms — had practically dis-
appeared. The animals, in fact, although of humble stature,
were true horses {E. sivalensis). Professor Ewart considers
that Arabs, barbs, thoroughbreds, and other modern breeds
have mainly sprung from these Indian Pliocene forms.
RHINO- Many must have been the paths made through the grasses
CEROSES and brushwood by the heavy tread of rhinoceroses. Fre-
quent, too, must have been their conflicts with sabre-toothed
cats, to say nothing of love-quarrels among themselves.
In addition to some members of the moribund, hornless line
(Aceratherium), there were certain two-horned forms (R. pia~
tyrhinus), ancestors probably of the so-called " white rhino-
ceros " of Africa. Other animals were of a species no members
of which ever seem to have wandered beyond the limits of
Asia {R. sivalensis, R. palceindicus). These animals are gener-
ally regarded as having been the ancestors of the one-
horned rhinoceroses now living in India. In course of time
the one-horned forms entirely supplanted the two-horned
in that country,

SWINE Pigs, resembhng for the most part those in Europe, were
common in the woods and swamps ; but the Indian animals
of the wild boar type were, as a rule, of larger size than
their European relations. In some cases, indeed, they were
as big as mules (5. titan). Others (5. punjahie^isis) were
extremely small ; and probably were ancestors of the pigmy
hogs of our own time (5. salvanius). There were also pigs
— not found in Europe — that seem to have been developing
in the direction of the Wart-hog, whose forbidding physiog-
nomy is now confined to Africa (Phacochcerus).

In addition to these various true pigs there were a number
of unconventional, though allied, forms. Old-fashioned
swamp-loving brutes with opossum-shaped skulls, and teeth
of a partly ruminant character, were surviving here, although
they had long been extinct in Europe (Anthracotherium) ;
and other uncanonical pigs were grubbing about with tooth-
peculiarities still more pronounced (Merycopotamus etc.).
All these anomalous creatures were shortly to disappear.

It is possible that some of the pig-like brutes of earlier

EARLIER PLIOCENE EPOCH

177

times had adopted more or less aquatic habits, and that their hippo-
descendants underwent various modifications, and finally potamuses
issued as hippopotamuses. However that may have been,
hippopotamuses of primitive type — with more teeth than
modern forms — were certainly at this time puffing and
grunting in Indian waters (H. sivalensis, H. iravaticus).

Long-necked giraffes were here and there plucking the giraffes
foliage of mimosa and acacia trees. So far as can be ascer-
tained these animals did not differ from modern giraffes.
The giraffe family, however, was not represented in India
solely by these highly developed forms. As in Europe there
were many short-necked and heavily built animals more
or less representative of earlier stages of evolution. These
vanishing types were well-armed beasts, and in some cases
almost attained the dimensions of elephants. Sivatherium,
the most notable of this strange company, was crowned
with stout antlers, and further armed with a pair of horns,
just above the eyes. Such beasts, though unable, like their
long-necked relatives, to note the approach of danger at
great distances, were of course much better able to take care
of themselves when pressed at close quarters. In spite,
however, of their bulk and elaborate armature, they were
not on the roll of Evolution's effectives.

In the desert regions camels, content with poor fare, camels
wandered in comparative safety {Camelus). They were
doubtless descendants of North American forms, that had
found their way to Asia by a land connection existing on
or near the site of Behring Strait. The animals of which
remains have been found in India more nearly resembled
modern camels than did their Miocene ancestors of the
American continent, as their teeth were reduced to the
present regulation number. The character, however, of
their molars shows that their distinction from lamas was
not so great as is the case with camels of our own time.

Goats were scrambUng about the heights, preferring, goats
like the camels, peace and simple fare to the luxurious but
risky life in lowland pastures. This is the first appearance
of these animals in geological history ; but as there were
several species, their annals must have commenced in much

178

EVOLUTION IN THE PAST

earlier times. For a long time their forerunners probably-
remained but little distinguishable from primitive antelopes ;
but in the earlier Pliocene goats had so far progressed as to
resemble species now Hving in the Himalayan mountain
ranges. Some with back-curved horns seem to have been
closely related to the Thar (Capra sivalensis, Hemitragus) ;
others, similarly horned, were forerunners apparently of
ibexes (C. sihirica) ; whilst yet other forms resembled, at
least in their straight spiral horns, the bearded Markhors —
the champions of the goat-world (C. Falconeri).
GOAT-OXEN Other related animals — that possibly had not taken to
a mountain life — were of less pronounced development,
being goat-like as regards the head, but toothed as oxen
(Bucapra). In common with the short-necked giraffes, the
ruminant-toothed pig-Uke animals, the hornless rhinoceroses,
the three-toed horses, and the long-chinned, and the bent-
chinned elephants, these animals stood out in strange con-
trast with the more modernised mammals. Nor were they
OXEN harbingers of oxen, for animals closely allied to the living
Yak had already appeared (Bos sivalensis). Primitive bison
were also about in herds, and small animals closely allied to
our domestic cattle (B. flanifrons).
ANTELOPE Whatever horned ruminants may have branched off from
primitive antelopes, antelope-life was well developed in
the linear direction. The evidence of this in Europe is more
than confirmed by that derived from India. Nilgai-looking
animals (ancestors of the cow-like short-horned antelopes
now living in that country) were certainly on the scene
(Boselaphus). Kudus and elands, more or less in an inter-
volved condition in Europe, were in India separately es-
tablished (Strepsiceros, Orias). Sable antelopes were also to
be seen, no longer characterised, as in the West, by strongly
marked affinities with the Oryx (Hippotragus). Whilst four-
horned antelopes (Tetraceros), hartebeests (Buhalis), and
small forms of water-buck (Cobus) bore further witness to
the varied development which antelope-life had undergone.
No nilgai ever seem to have left their Indian habitats ;
but in course of time kudus, elands, sable antelopes, harte-
beests, and water-buck all forsook their ancient haunts ;

EARLIER PLIOCENE EPOCH

179

and, excepting some hartebeests which did not proceed
further than Arabia, wandered away into Africa.

Chevrotains had by this time become almost extinct chevrotains
in Europe and North America, but in India many of these
hornless deer-like animals were haunting the jungles {Tra-
gulus). Owing to their small size, and defenceless condition,
they were probably of shy habits, keeping, like their living
descendants, in strict retirement during the daytime. Certain
species closely allied to water-chevrotains were also on the
scene ; but these were not destined for a prolonged career in
any part of Asia (Dorcatherium).

Some early ancestral species of deer, which had become deer
extinct in Europe in the last Period, were still living in
parts of India ; but they were now fast drawing to their
end (Palceomeryx). Small antlerless creatures were numerous,
and some of these were probably the immediate ancestors of
musk-deer (Moschus) ; whilst other forms, adorned with
antlers, were closely allied to the living Swamp deer (C,
sivalensis). Deer do not appear at any time to have found
their way to the continent of Africa.

Ape-life comes out more distinctly than in Europe, primates
" Holy " apes were carrying on their pranks in the woods ;
and macaques, more or less obscured in the West by strong
affinities with the " holies," were here of no doubtful identity
{Macacus). Baboons, by the suppression of features which
had closely connected their forerunners with man-like apes,
had also gained an individuality (Papio). Chimpanzees
were no longer in dubious condition by reason of gorilla
characteristics (Anthropopiihecus) ; and forms closely allied
to gorillas were now in view (Sivapithecus). WeU- developed
orangs were also abroad, and of more cheerful countenance,
it is to be hoped, than their descendants of to-day (Simia).

Here and there, in more open country, small parties ostriches
of ostriches were to be seen — their first known appearance in
life {Struthid). To judge, however, by primitive features
in its anatomy, the " camel-bird " may weU have strode the
earth long before Pliocene times.

Animals coming down to slake their thirst at lakes and crocodiles
livers had need of caution, for crocodiles, long-snouted,

i8o EVOLUTION IN THE PAST

and short-snouted, abounded. Among long-snouted forms
ancestors of the modern Ganges gavials were to be seen (G.
gangeticus). Some members of this species were formidable
creatures, much larger than their present-day descendants.
But they were surpassed in their day by monsters over
fifty feet in length, belonging to a species now long extinct
(Rhamphosuchus). Hippopotamuses, one might suppose,
must have found such giants unpleasant bathing companions.
It is stated, however, by recent travellers that hippopotamuses
and crocodiles live on excellent terms with one another.
Possibly this " mixed " bathing was innocently carried
on in Pliocene times.
TORTOISES No less remarkable for size were some of the tortoises.

Remains have been found of one of these animals whose
shell was eight feet in length (Colossochelys atlas). This huge
creature, safe in some insular habitat, must have died full
of years — possibly at an age of three hundred.
NORTH A journey must now be made from Asia to North America.
AMERICA This, as already stated, could be accompUshed entirely on
land. Unfortunately but httle is known of the " new
world life at this time. As in India, among horses with
diminishing " extra " toes some one-toed forms were to be
seen. Rhinoceroses — never successful in this part of the
world — were dying out. By reductions in number both of
teeth and toes these animals had certainly drawn nearer
to modern rhinoceroses, but they all continued hornless
(Aphelops). American rhinoceros-life, therefore, went down
to its grave with no slight imperfections on its head. Some
descendants of the early camel-like creatures had now
definitely developed into lamas (Auchenia). Descendants
of some of the Miocene pig-like creatures had distinctly
emerged as peccaries (Dicotyles) ; and old-fashioned elephants,
long-chinned and four-tusked (Tetrahelodon), were now sup-
plemented by forms of Mastodon type (Dibelodon).

Burrowing beaver-squirrels, horned on the snout — such
as appeared in North America in the Miocene — were still
in being (Mylagaulus), and new species had arisen {Epigaulus).
From some unknown cause all these curious underground
workers became extinct at the close of this epoch of the

EARLIER PLIOCENE EPOCH

i8i

Pliocene. Nor did they ever extend their range beyond
their native continent.

In South America the record is almost a blank ; but the south
peculiar fauna was doubtless prosperous, as may be inferred America
from its condition in the later part of the Period. This
continent had for a very long time been separate from its
northern neighbour, and its animal life had lagged far behind.
By the upheaval, however, of the Isthmus of Panama in
early Pliocene times, great additions to the native fauna
became possible. The tariff wall, so to speak, had ceased
to be ; and Southern American mammal-products were no
longer " protected." Northern mammals were now finding
their way to the long-inaccessible continent ; and, as a counter-
move, a few armadillos embraced the opportunity of
trying their fortunes in the North (Carioderma).

CAINOZOIC AGE

PLIOCENE PERIOD

LATER EPOCH

Later Pliocene strata record many changes in animal life,
both in development and distribution. The old-fashioned
long-chinned elephants (Teirabelodon), and the brutes with
tusks curving down from a bent under-jaw (Dinotherium),
seem to have become quite extinct, not only in Europe, but
in other lands.

EUROPE Europe was now invaded by mastodons (M. arvernensis,
elephants M. Bofsoni), and thither also had true elephants made their
way. Among the latter were some fine beasts (E. meridion-
alis), standing fully fourteen feet high — three feet taller
than " Jumbo " of recent fame.
HORSES One-toed horses which, so far as is known, were con-
fined in the earlier Pliocene to Asia and North America,
were now grazing on European pastures. Some seem to
have been of zebra character (E. stenonis) ; others were
possibly ancestors of Exmoor and other ponies of the so-
called Keltic type {E. ligeris). Old-fashioned horses with
" extra " toes were still to be seen, but they were insignificant
in number, and fast disappearing (Hipp avion).
tapirs Tapirs — numerous on the continent in earlier PHocene
times — were evidently finding conditions unfavourable, for
rhino- they were much reduced in numbers. Rhinoceroses, how-
CEROSES ever, still continued in force ; and some of them were now
furnished with big horns, effectively supported by increased
HIPPO- ossifications on the snout (R. etruscus). Hippopotamuses
POTAMUSES were bathing in the waters. These European forms, owing
to a reduced dentition, were more in fine with modern hippo-

CERVUS SEDGWICKI
Remains found in later Pliocene of Great Britain and Northern Italy

[To face fmge 1S3

LATER PLIOCENE EPOCH

183

potamuses than their Indian forerunners of the early PUocene

(H. amphibius). Ancestors of the modern wild boars of swine

Europe were now to be seen among the swine (S. scrofa) ;

also some new pig-forms (5. arvernensis). The latter seem

to have been related to the Bush pigs of Africa, and had,

it may be supposed, come from that continent — probably by

land-routes that have long since been submerged. Giraffes giraffes

had migrated to other scenes. Antelopes were still in Europe, antelopes

but, like the tapirs, they were greatly diminished in number.

Many of them, doubtless, had crossed to Africa. Ruminants,

however, were well represented by oxen, and several species oxen

of deer. Some of the latter were simply antlered, and appear deer

to have been descendants of the muntjac-like deer of the

earlier Pliocene (Cervulus). Whilst other forms possessed

antlers of roe-deer pattern (C. cusanus) ; and forefathers of

the red deer were also exploring the plains (C. elephus).

Remains have been found of a wonderfully antlered
form (C. Sedgwicki). This animal — probably broad-footed
like the Marsh Deer, and well-tailed like the Eland — ^possessed
antlers of excessive size and elaboration. Indeed, the arma-
ture must have been too cumbersome and complex for
effective service. As exaggerated development is often a
symptom of racial old age, this over-antlered form probably
represented a race of deer approaching extinction. The
history of the race in its youth and prime is quite unknown.
Indeed, almost in a single breath, one gives greeting and
farewell to these picturesque creatures.

Oxen, although in Asia in the earlier Pliocene, do not oxen
appear to have invaded Europe during that epoch, but they
were certainly there in the latter part of the Period. They
may well have been of more active habits than our domestic
cattle ; but probably they differed very little from them in
structure (Bos primigenius). It is doubtful, however, if
any of the females on either continent had as yet been pro-
vided with horns.

Wolves abounded in Europe ; but the " sabre-toothed " carnivores
cats still continued the most formidable of the carnivores
(MachcBYodus). The latter, however, doubtless paid most
attention to mastodons, elephants, and rhinoceroses, whose

EVOLUTION IN THE PAST

tough integuments they were specially quahfied to penetrate.
Among numerous other cat-forms some were shaping, so to
speak, into lions, some into lynxes. True bears were numerous
at this time in Europe, where also hyaenas were still to be
seen.

PRIMATES Carnivores in quest of prey no longer caught sight of anthro-
poid or man-like apes, for these had now deserted Europe.
Primates of lower rank were still represented, at least in the
southern parts of the continent, by " Holy Apes " (Semno-
pithecus). Macaques or Barbary Apes were also in the
forests {Macacus) ; as well as some long-headed apes of a
kind now quite unknown (Dolichopithecus).

CLIMATE The departure of many animals from Europe was doubt-
less owing to a fall in the temperature, and not a few that
remained in the northern regions were finding themselves in
" the winter of their discontent." A moist and almost
tropical climate had prevailed on the continent during the
Eocene and Oligocene Periods, and had continued through
the greater portion of the Miocene. Towards the close of
the last Period it is clear that climatic changes were in pro-
gress, as the palms ceased to flourish. That the temperature
was still declining in the early Pliocene is shown by the
continued dwindling of the palms, the suppression of much
warmth-loving vegetation, the increase of grasses and de-
ciduous trees, and the retreat of crocodiles. In the later
Pliocene, palms and other tropical and subtropical growths
seem to have disappeared entirely, and the verdant scenes
presented an aspect much as that of to-day.

Further evidence of a falling temperature in Europe is
afforded by the migrations of moUuscan life. In Eocene
and Oligocene times the molluscs more or less resembled or
belonged to species that now thrive in tropical regions.
Towards the close of the Miocene various warm-water
species had moved southward. This migration continued in
the Pliocene, and the relinquished haunts were occupied by
hardier molluscs from northern latitudes.
NORTH Little has as yet been discovered of later Pliocene life

AMERICA in North America. Some remains have been found which
suggest lion-like animals ; and there is evidence that some

MEGATHERIUM
A gigantic ground-sloth

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LATER PLIOCENE EPOCH

185

of the horses were taller than the pony-sized creatures of
earlier times. Ground-sloths of South America had now
crossed the Isthmus (Megalonyx), adding a new feature to
the fauna.

Many animals had quitted the northern for the southern south
continent, availing themselves of the recently raised land America
connection. Horses, mastodons, tapirs, lamas, and other
herbivorous emigrants were now well south of the isthmus ;
and carnivores, dog-like and cat-like, were not losing sight
of their commissariat. Marsupial life was augmented by
the arrival of some good-sized opossums.

This invasion cannot have been without effect on the
southern fauna. But the continent was of vast extent, and,
so far as can be gathered, the development of the native
animals was not as a rule seriously checked. In some regions,
indeed, it progressed remarkably. Ground-sloths of larger
size than the Miocene forms were now in the forests {Mega- edentates
therium, Mylodon) ; and other Edentates were abroad,
resembling ant-eaters at least as regards the skuU (Scelido-
therium). Armadillo-life was not only characterised by much
larger animals, but by a great variety of forms rigidly en-
cased. Some of the new kinds were shielded more elaborately
than their forerunners, and their tails were protected by
bony tubes and rings (Dcedicurus, Panocthus). Ground-sloths
and armadillos were, therefore, rising to the occasion ; and,
as their later history will show, they had by no means ex-
hausted their adaptabilities.

The various strange types of hoofed animals, such as
lived in South America in the Miocene, had by this time
undergone many changes and some losses. The astrapotheres, astra-
Temarkable for doubly-tusked brutes of rhinoceros size, had potheres
become extinct. As some animals more or less allied, but
less formidably armed, were still in existence, the " lightning-
beasts " can hardly have perished from lack of brute force.
Brute force, however, had long been a declining power in
creation ; and it was probably owing in the main to mental
deficiencies that the astrapotheres failed to survive.

Among their relatives, known as toxodonts, and suggestive toxodonts
in appearance of coneys overgrown, new species had arisen.

EVOLUTION IN THE PAST

These for the most part consisted of larger animals than their
Miocene forerunners ; and it is evident from their teeth that
they were converging more closely to creatures of the rodent
TYPOTHERES type (Toxodontotherhtm). The still more rodent-like typo-
theres, with an aspect of guinea-pigs grown to giants, had
also increased in size.

LITOPTERNS The lama-like litopterns do not seem to have improved in
stature ; but it is of interest to note that in the case of some
of the animals the breathing aperture in the skull was located
higher up than in the Miocene forms (Scalahrina). This
suggests that a proboscis was in process of evolution. The
nasal modification, as will be seen, was carried still further in
litopterns of the next Period. The small forms, which had
anticipated horses in developing one-toed feet, seem by this
time to have been on the verge of extinction {ProteYotheriidcB) ;
whilst the antiquated hippopotamus-bears had quite passed
away (Pyrotherium).

Although there were losses, it must be admitted that
the native fauna, at least in some regions, continued to
prosper. In parts of the continent, however, the quaint
aborigines were experiencing different treatment. Alien car-
nivores were levying heavy tributes, and extensive areas of
fertile land were being appropriated by hordes of new herbi-
vores. In short, a state of affairs was in prospect analogous
to that experienced by the South American natives when the
Spaniards invaded their dominions.

AUSTRALIA Whilst the native fauna of South America had, as a whole,
lagged behind the animal-development in most parts of
the world, a still more backward condition existed in Australia.
Indeed, no mammals of higher rank than marsupials in-
habited that territory. This was doubtless owing to its
having become enisled before the commencement of the
Eocene Period. It had thus been cut off from the great
originating countries ; and the mammal life — already far
committed to marsupiahsm — proceeded with limited ana-
tomical resources.

MARSUPIALS These resources, though restricted in scope, came weU into
play, as testified by the variety of the fauna. Generahsed
creatures with affinities to wombats as well as to kangaroos

PITHECANTHROPUS

( I u uue page 1S7

LATER PLIOCENE EPOCH

187

were about the land (Diprotodon) ; and also animals specialised
into one or other of those forms (Phascolomys, Macropus).
There were also creatures somewhat of phalanger type, and
known as " pouched lions " (Thylacoleo) ; and animals civet-
like in outward appearance were roaming about (Dasyurus).
But it was in the next Period that Australian marsupials
reached the climax of their development.

As anthropoid or man-like apes had emerged in the Miocene, apes
it would cause no surprise if proof were found of contemporary and man
creatures of still higher type. It is not, of course, supposed
that man is descended from gorillas, chimpanzees, or other
of the anthropoid apes ; but it is generally thought that man
and the anthropoids have come down from a common stock,
represented possibly by Propliopithems of the late Eocene.
Some members of the stock had at some time diverged,
and resulted in the Miocene as man-like apes. And it is not
unreasonable to suppose that there had been another diver-
gence from the stock in the direction of human beings.
If such were the case it may fairly be assumed that these
more progressive creatures — having possibly developed a
taste for meat — had gained greater brain power, and were
no longer so intimidated by their surroundings as to pass
most of their lives in the trees of the forests. Although at
first indifferent pedestrians, such individuals, as their walking
habits became confirmed, would tend naturally to assume
the erect posture.

There is, however, no satisfactory evidence of such superior pithec-
animals either in OUgocene or Miocene times ; but it is clear anthropus
from remains found by Eugene Dubois in 1894 in Java that
such were living in the latter part of the Pliocene {Pithec-
anthropus eredus). These Javan remains are very scanty,
consisting only of the upper portion of a skull, a thigh-bone,
and three teeth. These are presumably all relics of one in-
dividual, that stood probably about five feet in height.
The skull has massive ape-like brow-ridges ; but it must
have contained brains larger than those of any anthropoid
ape now existing, and, indeed, equal in amount to those
of some of the lowest savages of to-day. The thigh-bone
cannot be described definitely as that of a human being,

EVOLUTION IN THE PAST

as it has some simian characters ; and the same remark
appHes to the teeth. It seems, therefore, that Pithecan-
thropus fell short of being a human creature, but was some-
thing above an ape. He may, therefore, be regarded as a
member of the more progressive section that had diverged
from the stock in which anthropoids and men had existed
as intermixed possibilities. He may, in short, be termed a
super-ape.

As to his manner of life but little can be surmised. His
food probably consisted of small mammals, eggs, roots,
and berries. Big game certainly haunted his neighbourhood
— elephants, rhinoceroses, and hippopotamuses ; and there
were also wild boar and oxen. But it is doubtful if he had
the wit or the power to overcome any of these animals. The
particular individual of which remains have been found
cannot, it may be mentioned, have been of very active
habits ; for the state of his thigh-bone shows that he was a
martyr to rheumatic gout. This affliction, it is to be feared,
he had to abide without remedy.

Whether he and his fellows — for there must have been
others of his kind — had learned to manufacture tools and
weapons cannot, for want of evidence, be determined. It is
highly probable they had some skill in chipping stones, for
rude flint implements, known as eoliths, have certainly been
brought to light from later Pliocene strata. These relics,
however, have not been found in Java.

Many eoliths, indeed, have been discovered in equivalent
strata of France and England. It would seem, therefore,
that in the later Pliocene, super-apes, if not men, were living
in western Europe. No other signs, however, of such beings
have been discovered. The increasing coolness of the climate
leads one to suppose that these explorers, if not astute enough
to clothe themselves with the skins of animals, must have
had their bodies well covered with hair. In any case, their
conditions must have become exceedingly trying as the
Great Glaciation approached.

QUATERNARY AGE

PLEISTOCENE PERIOD

The temperature of the northern hemisphere had been
more or less dechning ever since the later Miocene. This,
no doubt, had in great part been owing to long-sustained
land-upheavals. At the close of the Pliocene and the com-
mencement of the Pleistocene the cold was steadily increasing.

Apes and tapirs, it would seem, had migrated from Europe
by this time ; and climate had doubtless caused many other
migrations, and also some extinctions. The temperature,
however, had not sunk so low as to prevent hippopotamuses
making excursions to the continent, at least in the summer
months. Huge elephants of the same species as those of the
last Period were also still able to find suitable accommodation
(E. meridionalis) ; and the presence of some straight-tusked
forms testified to fresh arrivals of proboscidean life {E.
antiquus). Horses of a new species were now on the plains
(E. cah alius), as well as descendants of the zebra-like forms
of the PUocene (E. steno7iis). The new-comers had migrated
probably from some inhospitable scenes in the north of Asia ;
for they bore close resemblance to the wild horses now living
on the deserts of that continent {E. Przewalskii). Other
forms appear to have been intermediate between the last-
named and the zebra-like animals (E. Heidelbergensis).

Climate, however, in the more northern latitudes was
fast driving life down from old abodes. Many of the trees
and other growths in those regions must have been suffering
from the cold, for even the hardy Spruce Fir (Abies excelsa)
was beginning to retreat from its far northern ground. And
wolves, gluttons or wolverines (Gulo), elk {Alces latifrons),
musk-oxen (0. moschatus), mountain sheep (0. Savigni), and

189

I90 EVOLUTION IN THE PAST

grizzly cave-bears (U. spelceus) were wandering far south of
ancient haunts.

PRE-GLACIAL There is some scanty evidence of the presence of man
MAN in Europe at this time {Homo Heidelhergensis). The remains
are too imperfect to afford much information as to his con-
dition of development. The evidence points to an ape-hke
physiognomy — an under -jaw massive and chinless, and
characterised by other pithecoid features. The roots of
the teeth were remarkably stout and strong, but the crowns
were of human character. The powerful jaw must have
had great crushing power, and the man, one may well suppose,
was much better at biting than at talking. His speech
indeed, such as it was, probably required considerable gesture
and grimace in order to render it intelligible. It seems to
have been the custom of the race to bury flint flakes with the
dead. Possibly, therefore, belief was held in an after-life in
which implements would still be required. Physically these
people may not have differed much from the contemporary
anthropoid apes — fellow-descendants from a common stock ;
but in the matter of culture the difference, one may infer,
was already well pronounced.
GLACIATION As the Period advanced, land-upheavals continued, and
refrigeration of the climate became more marked. Vast
elevated areas, especially in Scandinavia, became the gather-
ing grounds of immense quantities of snow ; and huge glaciers
issuing from the snow-fields streamed through the valleys,
and over the plains. They even invaded the Atlantic ;
but here they were soon undermined and broken up into
bergs. Great migrations of the fauna must have ensued
in all the affected lands, and much of it doubtless perished.
Forlorn enough must have been the look of the landscapes.
Trees withered away, or grew scarcely bigger than bushes ;
and on once genial and fertile scenes of lower latitudes,
polar willows (Salix polaris), dwarf birches {Betula nana),
boreal mosses (Hypnum turgescens) and other arctic migrants
alone possessed the ground.
ASIA Similar conditions prevailed in parts of Asia. Great
glaciers were travelling from the Ural Mountains in an
easterly direction ; and Siberia was threatened with ex-

PLEISTOCENE PERIOD

191

ceptionally severe conditions. Thick-haired mammoth-
elephants with big curhng tusks (E. primigenius), and rhi-
noceroses in woolly apparel (R. tichorhinus), that had long
gathered sustenance in those frosty regions from spruces
and junipers, were now seeking new feeding grounds. Many
of the mammoths, no doubt, were moving to less inhospitable
parts of Asia ; some were seeking European pastures ; others
were migrating to North America on the land-way then
existing in the Behring Strait region. Some of the woolly
rhinoceroses wandered into Europe — among them a few
curious forms with a huge horn rising unicorn-like from
the forehead (Elasmotherium). So far as is known no rhi-
noceroses faced the terrible north-eastern journey, under-
taken by some of the mammoths.

Nor were the central and southern parts of Asia wholly
exempt from great ice visitations. The Himalayas certainly
formed a centre for ice dispersal ; and numerous glaciers
rolled to the south and west from the snow-hidden mountains.

From elevated lands of Labrador in the east, from central north
snow-fields amassed in Keewatin, and from half-buried America
" Rockies " away in the west, glaciers were bringing vast
stretches of North America much into the condition of that
of northern Europe.

The increase of the cold had been gradual ; and many
animals by timely retreat had doubtless escaped suffering
and death. The destruction of life, however, in North
America must have been very great, as well as in Europe
and Asia.

In the long course of years the glaciers, increasing in europe
volume, rose high up the mountain-sides that hemmed them
in. Finally the heights were overridden ; and numerous
glaciers, uniting across the topmost ridges, formed vast
sheets of continuous ice. An ice-sheet seems to have ex-
tended practically over the whole of northern Europe ;
for evidence shows that Ireland, Wales, Scotland, England
(as far as the Thames Valley), the North Sea, Norway,
Sweden, Denmark, Holland, Germany (as far south as
Dresden), the greater part of Russia, and the whole of the
Baltic Sea were covered with ice and snow. Switzerland

192

EVOLUTION IN THE PAST

also was completely overspread ; but the ice-sheet here
seems to have been formed independently by local glaciers.
Over scenes in Germany, where in earlier times palms and
cinnamons had flourished, polar bears were roaming. Great
indeed had been the change.
NORTH The moraines show that the southern extension of the
AMERICA sheet in North America was much greater in the east than
in the west ; but more than half the continent was covered
with thick ice from the Atlantic to the Pacific. The massive-
ness of the ice in some regions was enormous. In parts of
North America (and in parts of Scandinavia) the thickness
must have been fully 3000 feet. And in regions far beyond
the limits of the ice-sheets the cold must have been
intense.

EUROPE These conditions, varied by occasional relaxations, con-
tinued for a long time. At length in Europe, owing chiefly
to land subsidences in the more northern latitudes, a steady
change towards mild conditions set in. Exposed masses of
pushed-on debris now marked the lost frontiers of the icy
sway. Traversed rocks reappeared, scratched and polished
after long entombment ; and huge glacier-transported boulders
were to be seen perched on mountain-tops, hundreds of miles
away from their pre-glacial abodes.
INTER- We now reach in Europe what can only be called an Inter-

GLACIAL glacial Epoch, for in course of time a second Great Glaciation
EPOCH IN took place. Although there were several relaxations of the

EUROPE intense cold in North America, it is not at all clear that
there was any inter-glacial epoch of importance such as
occurred in Europe.

The gradual melting of the ice, and an abundant rainfall,
resulted in great floods, and the removal of vast amounts of
surface earth from place to place. New lakes were formed
in basins hollowed out by the glaciers ; and in some cases
old rivers, finding their former channels blocked by glacial
debris, were making their way by new routes to the sea.

The change of climate in Europe, involving the recession
of the ice, was followed naturally by many migrations of
life. Polar willows, dwarf birches, hardy forms of saxifrage,
and other cold-climate growths were gradually advancing

PLEISTOCENE PERIOD

193

over the ice-vacated lands. Spruces and junipers were
also northward bound, and grasses were once more carpeting
desolated valleys and plains. Poplars, oaks, hornbeams,
sycamores, and other deciduous trees were also coming up
from southern exile ; and old landscapes, open again to
sunshine, slowly recovered a long-lost wealth and beauty.

Many vigorous species long survived in the southerly
latitudes to which they had been driven ; and as the warmth
increased they sought and found congenial conditions on
hill and mountain altitudes.

Northward, too, was animal life pressing, with seals and
polar bears in the van, followed by mammoths, woolly
rhinoceroses, wolverines, musk-oxen, elk, and other hardy
animals.

What, it may be asked, had become of the descendants
of the European Pliocene fauna when the Great Glaciation
was prevailing — the elephants, rhinoceroses, hippopotamuses,
horses, deer, " sabre-toothed " cats, and other forms of
life ? Some species had, no doubt, died out. Some had
found congenial quarters in the south of Europe, others
had crossed to Africa. As the refrigeration increased great
migrations must have taken place to the latter continent ;
for it was easy of access, being connected at that time not
only with Spain across the Gibraltar Strait, but with Italy
also by continuous land now represented only by Malta
and Sicily. As genial conditions returned, the exiled species
sought out the haunts of their forefathers ; and straight-
tusked elephants (E. antiquus), rhinoceroses of a non- woolly
kind (R. etruscus), hippopotamuses, and other descendants
of the earlier fauna were to be seen well north of the Medi-
terranean. The species of zebra-like horses which had
arrived in Europe in the later Phocene (E. stenonis), and
was represented there in the early Pleistocene, seems to
have become extinct at the time of the Great Glaciation.
The later species arriving in Europe in the early part of
the Pleistocene, and resembling the wild horses now living
in Asia, was certainly again in Europe when the ice was
in retreat (E. cah alius). The species of elephant in view
in the early portion of the Period, and notable for extra-
o

194

EVOLUTION IN THE PAST

ordinarily big animals, appears to have become extinct
(E. meridionalis). " Sabre-toothed " cats were certainly
in Europe at the commencement of the Period, but it is
not clear if they formed a part of the inter-glacial fauna.
The principal butchers on the continent seem to have been
big lions of African type (Felis spelcea).

SIBERIA The condition of Siberia during the Inter-glacial Epoch
cannot, for want of data, be determined. It seems probable
that its chmatic fluctuations had not been moving pari passu
with those of Europe. At any rate an influx of animals from
western Siberia to Europe took place during the Inter-glacial
Epoch ; and the various emigrants formed a significant
portion of the fauna. There may have been some important
changes in Siberian chmate to prompt this movement ;
or it may have been the result of greater facilities for migra-
tion, owing to some redistribution of land and water on the
border lands. The route of the emigrants seems to have been
between the Ural Mountains and the Caspian Sea, across
the site of the moss-clad, treeless plains now known as the
Kirghiz Steppes. From these dreary scenes herds of rein-
deer (Rangifer tarandus), and saiga antelope (Saiga tartarica)

EUROPE were now appearing in various parts of Europe. Arctic
foxes (C. lagopus), and badgers (Meles) were also among
the new arrivals ; and elk, musk-oxen, wolverines, and
" cave " bears — frequenters of Europe during the Glaciation —
were greatly reinforced. The so-called Gigantic Irish Deer
(C. giganteus) was also in Europe at this time. It is not
clear if the species originated in Europe ; in later times
it was represented in Ireland in great numbers. These
animals were closely allied to the fallow deer, and must have
been magnificent creatures. The antlers in some instances
measured as much as twelve feet across, and weighed over
a hundredweight.

There was thus a strange collection of life on the continent
during the Inter-glacial Epoch. The chmate, however,
was of course not uniform, and must have varied from warm
and temperate to an intense cold in the plateaux and moun-
tainous regions. A great deal of the land, released from ice,
probably had only a scanty covering of mosses and scrub

PLEISTOCENE PERIOD

195

vegetation ; but such forlorn scenes were well suited at least
to the steppe-loving reindeer and the saiga antelope.

Here was a happy hunting-ground for man, and there is
evidence of his presence. Indeed, the pursuit of prey may
well have drawn him to this well-stocked scene. As to his
abihties as a hunter, it is impossible to form a precise idea.
Many of the animals were probably too formidable for him
or too fleet of foot ; and except in the case of sickly animals,
and those disabled by accident, capture of big game must
have required considerable strategy. He certainly possessed
pieces of flint chipped down to a sharp edge, and in some
cases rudely wrought into scraper-form. How far these
implements — known as palaeoliths — were useful in the chase
it is impossible to say. One cannot imagine their effective-
ness to have been great ; and as a rule it was probably by
means of cunningly concealed pits that big game was cap-
tured. When, however, the prey had been secured, the
implements, no doubt, proved highly serviceable for cutting
up the carcase for food, and scraping out the skin for clothing.

These implements, although rudely manufactured, exhibit,
nevertheless, more skilful workmanship than the eoliths of
the last Period. And the better workmanship tends to
show that the possessors were more highly cultured than
the men or super-apes of the Pliocene. The human race
was progressing, but its hardships and dangers must have
been very great.

If the remains discovered in the Neander Valley near
Stuttgart may be taken as relating to this time, these inter-
glacial hunters were sturdily built, and stood about five and
a half feet in height. Their skulls were of a low type, much
depressed at the top ; and their foreheads were receding,
and without width or depth. Their brow-ridges, like those
of Pithecanthropus, were massive and projecting ; and
this must have given them an ape-hke physiognomy. Their
cranial capacity was, however, much greater than that of
the Javan super-ape. Some parts of the skeleton — notably
the outer bone of the forearm and the shoulder-blade —
possessed simian characters. The thigh-bones in being
slightly curved resembled those of human beings, and so

196

EVOLUTION IN THE PAST

differed from the straight, ape-like thigh-bone of Pithecan-
thropus. As regards hands, the individuals were quite
human.

It is clear from the remains that one of these inter-glacial
hunters met with a severe accident, resulting in the dislo-
cation of his elbow-joint. This injury had been neglected,
owing probably to sheer ignorance as to how to deal with it.

Other remains recently (1907) discovered also probably
belong to this epoch (H. mousteriensis Hauseri). These
men had markedly receding foreheads. Their jaws were
much protruded, giving the face an ape-hke muzzle, such as
is possessed by some of the Australian aborigines. They
also resembled those savages — and, indeed, all negroids —
in possessing wide and flattened noses. Their dentition
was of a powerful character; and the teeth, in being very
strongly rooted, possessed a simian character. In dis-
quieting circumstances these were doubtless displayed in
true animal style.

The aborigines of Australia probably come nearest to
these old wandering hunters, both as regards physiognomy
and culture. But even they — the lowest of living savages —
possess skulls of higher type.

Thus then Europe revived, and became the scene of a
miscellany of brute hfe such as had never before been
gathered within her borders. Man, too, was there ; destined
to kingship, but as yet far from the establishment of his
sovereignty.

These inter-glacial conditions, including minor fluctua-
tions, may have lasted some thousands of years ; but it is
impossible to ascertain their duration. Certain it is that
in course of time, owing chiefly to land-upheavals, there was
a persistent lowering of temperature ; and great glacial
streams once more overran northern Europe.
RE-GLACIA- Gradually Ireland and Scotland were re-buried under ice
TION OF and snow ; so also were parts of northern England. The
EUROPE North Sea was frozen over from coast to coast ; and Norway,
Sweden, Finland, and Denmark were once again overwhelmed.
The ice-sheet, however, never became so extensive as at the
maximum of the first glaciation. The greater part of England,

HOMO MOUSTERIENSIS
Remains found (1908) in Lower Grotto of Le Moustier, Dordogne

[To face pa£e igS

PLEISTOCENE PERIOD

197

and the whole of Holland, escaped it ; its southern reach was
less in Germany : and nearly the whole of Russia seems to
have been free. Switzerland, however, was again entombed
by locally formed glaciers.

This second glaciation, though less widespread than
the first, must have entailed many migrations, and some
extinctions of life. Where retreat was not cut off, animals,
that had penetrated to the north, naturally moved down
to lower latitudes, and elephants and hippopotamuses
probably migrated as far south as Africa. At the same time
northern species of plants spread in southerly directions,
following in the wake of temperate species seeking congenial
conditions further south. The cold must, at times, have
been very great, even in central Europe, for reindeer, arctic
foxes, and wolverines occasionally came as far south as the
Mediterranean.

As the conditions in Siberia seem at this time not to have SIBERIA
been exceptionally severe, and as most of Russia was free
of the ice-sheet, some of the mammoths, woolly rhinoceroses,
and other descendants of Siberian emigrants in Europe
may have returned to the lands of their forefathers. It
is likely, however, that most of them remained in Europe,
as in many parts they must have found the climate quite
tolerable and food sufficient. And if they remained in
force, so also would carnivores.

Long was the greater part of northern Europe under EUROPE
the icy mantle ; and, save for the sweep of air currents,
the silentness of vast expanses of country remained unbroken.

But all things, however unpleasant, come to an end.
Upheaved lands in course of time subsided ; the accumulation
of snow on the great gathering grounds grew less and less ;
the vast ice-sheet was again in retreat, and great migrations
of life ensued. This retreat of the ice may be spoken of as
final, for the earth has not since experienced a glacial visita-
tion.

There is no evidence to show if the descendants of the
inter-glacial hunters remained in Europe during the second
great glaciation. But as soon as the ice commenced to retire
men were roving about the continent.

198

EVOLUTION IN THE PAST

POST- GLACIAL Taking the remains discovered at Spy in Belgium as belong-
HUNTERS IN ing to this time, some of these men seem to have been of
EUROPE the same race as the inter-glacial hunters. Their heads
were very similar — narrow, depressed at the top, heavily
browed, and low-foreheaded ; whilst in the outer bone of
the forearm, and in the shoulder-blade, there were the same
simian characters. The remains further bring to light that
they were large-footed individuals, and possessed massive
chinless jaws with projecting incisor teeth, and molars of
simian character. The adults were probably not far short
of having attained an erect posture when walking ; but from
the construction of the leg-bones below the knee, the body
must have had a distinctly forward bend. The children
may have had to wait for some years before dispensing with
the arms in locomotion.

But although physically these people closely resembled
the inter-glacial hunters, they were in the enjoyment of a
somewhat higher culture. Their stone implements, though
rudely wrought, were better fashioned and more varied in
shape. In addition to flints roughly chipped for cutting
and scraping purposes, they possessed hand-hatchets and
borers ; and also " duck and drake " stones with chipped
edges for use as missiles. It is doubtful, however, if they
possessed any weapons which would make them successful
hunters of big game.

Contemporary more or less with these rude hunters were
men of another race [Galley Hill skeleton (1888), Homo
Aurignacensis Hauseri (1910)]. These individuals — if the
remains are typical — were about five feet in height, and
possessed disproportionately long thighs. Their heads were
long and narrow ; the face was short but well foreheaded ;
whilst the neck was that of a gorilla for thickness. As regards
brains they were certainly better off than the men of the
other race. Moreover, they were graced with chins, although
not of high type ; and their under- jaws were of lighter struc-
ture. From the development of the mandible it is supposed
they were able to talk with far greater facility than the big-
jawed, chinless hunters. Indeed, the speech of those men
was probably little better than a confused jabber.

PLEISTOCENE PERIOD

199

These races flourished in Europe for a time ; but long
before the mammoth and woolly rhinoceroses had quitted
the scenes, and whilst herds of reindeer still roamed over
the central lands, they were superseded by another race of
men. If we may take human remains discovered at Mentone,
at Engis on the Meuse, and at Cromagnon in the Dordogne
as typical of the new men, there was no close relation-
ship between them and the earlier races — certainly
not with the big- jawed hunters. Their skulls were well-
pitched — not depressed — at the top. The brow-ridges, it
is true, were strongly developed, but not to an ape-like
extent. Moreover, the forehead was not receding ; the
nose, though flattened at the root, projected well from the
face ; and the chin was considerably developed.

These new-comers to Europe are generally known as the cave
" Cave Men," as our knowledge of them is derived chiefly men
from deposits in ancient caves. The implements which
they had in use were still of the type known as palaeo-
Uthic or " old stone " — rudely fashioned, and showing no
signs of having been ground or polished. There is, how-
ever, evidence that the implements were better adapted for
use.

How far it had occurred to the earlier races of men that
their implements might be made more effective by being
fixed to shafts and handles is not certain ; but these men
undoubtedly had the knowledge, and made no little use of it.
Handled hatchets were taking the place of hand-hatchets.
Lances and javelins were in use, and greater success in
the chase must have been obtained. Moreover, there was
thus better provision against ferocious animals. Lions,
wolves, and bears were abroad ; and " sabre-toothed " cats
were certainly again in Europe at this time.

These men were mighty hunters, and they seem to have
coveted the reindeer beyond all other beasts. Indeed, the
reindeer was a good " all-round " animal for the men of those
days — the flesh and marrow-bones for food, the horns for
tools and weapons, the skin for clothing and cave-curtains,
and (when cut into strips) for binding on lance-heads and
hatchet-handles. They were able, if necessary, to saw the

200

EVOLUTION IN THE PAST

horns and bones, as they possessed — what the earlier men
lacked — flakes of flint toothed on the edge.

Besides reindeer, horses (E. cahallus) were slain and eaten.
Bison also were dragged back to the caves in triumph. Woolly
rhinoceroses were now and again victimised ; and even
mammoths were at times secured, and their curly tusks no
doubt set up as trophies.

In some cases fishing was undertaken, apparently with
a sort of harpoon made of bone ; and salmon coming up
the rivers to spawn were occasionally captured. Fowling
was also carried on ; and the cave evidence shows that
ptarmigan, willow-grouse, capercaillie, and other species
of northern birds fell to the craft of the fowler.

The Cave men, therefore, at least during some parts of
the year, lived well ; and as they were acquainted with fire,
they probably cooked their food.

The remains of bone needles prove that the art of sewing
was known. Probably reindeer sinew — another use of the
animal — furnished the thread.

There are grounds for believing that in some districts
the people daubed themselves with a mixture of grease and
red chalk. Pierced teeth and sea-shells give further evidence
of a love for personal decoration. Some of the shells used
were fossil, and may, indeed, have been prized on account
of their rarity.

The artistic tastes, however, of the people were not ex-
pressed only in necklaces and body-painting. They were
well able to scratch pictures on horn, bone, and ivory ;
and numerous clever and spirited representations of mam-
moths, reindeer, and other animals of the chase have been
brought to light. There is also evidence that fresco-painting
was attempted in the cave-dwelhngs (Gretas, and Cogul in
Spain).

It will be admitted, therefore, that the Cave men had
got well beyond the evolutionary stage in which attention
is focussed almost entirely on eating, drinking, and multiply-
ing.

Quarrels may have been frequent. From remains dis-
covered in the Dordogne it is clear that one of the women

PLEISTOCENE PERIOD

201

had been the recipient of a blow on the head, probably
from a hatchet. " First Aid," apparently, was available,
for medical experts, after careful examination of the skull,
declare that some rude sort of operation was performed.
What success attended this primitive surgery is unknown.

A glance must now be taken across the Atlantic, where north
North America was left under thick ice. As the ice-sheet America
extended its range, a course of events similar to that of
Europe must have taken place, involving great migrations
to lower latitudes.

Not far south of the fringe of the ice-sheet arctic willows,
dwarf birches, and other cold-chmate vegetation furnished a
meagre adornment to the landscape. Here, too, were mam-
moths, musk-oxen, reindeer, and other animals inured to
cold. Further south, horses, lamas, bison, and mastodons
found quarters pleasant enough, save for the wolves and
" sabre-toothed " cats that followed them to exile. Cali-
fornia, there is reason to beUeve, became a great rendezvous
at this time for glacial refugees. Some of the tapirs, peccaries,
mule-deer, and many of the mastodons probably migrated
across the Isthmus into South America. In that direction
also — towards the ancestral home — must many descendants
of the Pliocene emigrant sloths and armadillos have been
retreating. Even in southern latitudes the cold must
occasionally have been very severe ; for mammoths —
denizens of chilly regions — were at times down south as far
as Mexico.

Numerous must the migrations have been ; and there is no
reason to suppose that the destruction of animal life was
absolutely appalling. The oncoming of the ice was gradual,
and the facilities for migration were great.

In course of time, after several occasional relaxations, ice retreat
a persistent rise of temperature set in, and better days were in north
in dawn. America

At no time had the thick ice originating in Canada advanced
very far into the western States of North America. But in
the eastern States it travelled down over five hundred miles.
As the ice yielded, Illinois, Iowa, Indiana, Ohio, Michigan,
Wisconsin, Minnesota, Pennsylvania, New York, and other

202

EVOLUTION IN THE PAST

States long buried gradually reappeared ; and in course
of time vast tracts of Canada were relieved of their load.

What has been said about Europe at the time of the ice
retreat applies more or less to North America. Great floods
followed — more destructive, perhaps, to animal life than had
been the gradual extension of the ice-sheet. The Missouri and
Mississippi Rivers, with vastly widened courses, must have
fairly plunged along. New lakes were formed in many parts
of the country ; and desolated scenes were slowly clothed
with a northward-bound scrub vegetation of arctic character.
Forests, in time, began to form in favoured districts ; and a
general trend of animal life set in from the congested southern
areas.

In course of time so genial did the climate become that
mastodons roamed over the northern States, and even entered
Canada. Mastodons had become extinct in the old world in
Pliocene times ; and they are not known anywhere after the
Pleistocene. Many of them were ending their days in America
somewhat ingloriously — wandering into boggy lands (ap-
parently in search of salt), and perishing after vain efforts to
extricate themselves. Mammoths, by this time, must have
wandered far away north.

There is no satisfactory evidence that man was in North
America in pre-glacial times. Nor is it certainly known that he
was there during or even soon after the glaciation. Imple-
ments, apparently palaeolithic, have been exhumed ; but
there is no general consensus of opinion as to the date of the
beds in which they have been found. Indeed, it is affirmed
by some authorities that these so-caUed palseoliths are the
refuse flakes of well-finished implements made by Indians in
much later times. But whatever be the true date of the
reUcs, the human race was probably represented in Europe
much earlier than in North America.
SOUTH South America was also visited with an exceptional amount
AMERICA of ice ; but this may have been later in the Period than the
time of the great northern glaciation. In the region of the
Andes the valleys were blocked with ice. There was also
an ice-invasion from the far south, but this did not extend
north of Patagonia. The ice, however, never seems to

HIPPIDIUM

South American desert horses of the Pleistocene Period

[To face page 203

PLEISTOCENE PERIOD

203

have assumed appalling dimensions in any part of the
continent.

By the upheaval in the Pliocene of the land now known
as the Isthmus of Panama the animal life of South America
had been greatly enriched. And horses, mastodons, tapirs,
lamas, and other animals had come to mingle with the native
fauna. The exports of South America fell far short of her
imports, for, beyond some armadillos and ground-sloths,
she seems to have sent but little in return to her northern
neighbour. Great gain, moreover, had resulted to her from
the migrations of North American life consequent on the
great glaciation. As the glaciation relaxed, counter-migra-
tions led, no doubt, to some losses in her fauna. She had,
however, been permanently enriched. Horses, mastodons,
peccaries, and mule-deer did not wholly desert her ; whilst
some forms of life — notably lamas — never recrossed the
isthmus, and became lost to North America.

Some of her horses now exhibited certain differences from
their emigrant ancestors of the last Period. The most
notable of these modified forms were about the size of Shetland
ponies ; and their heads were disproportionately large for
their bodies {Hippidium, Onohippidium). The most striking
feature of the animals was the elongation of the nasal bones,
giving the head greater depth than that of the other horses.
And the nostrils, it may be assumed, were somewhat drawn
back. The scenes which these animals frequented were
probably different from those of their relations Uving on grassy
plains. Mr. Lydekker considers that the nasal modification
was probably a special adaptation to desert life ; and that by
its means particles of sand were prevented from reaching
the organ of smell. Towards the close of the Period horses
became extinct in South America. Professor Fairfield
Osborn considers this to have been caused by some wide-
spread epidemic.

South America, as has been seen, was not merely a collector
of animals from other lands ; and some of her whilom native
products have acquired considerable posthumous fame.

Her ground-sloths and armadillos — first in view in the
Miocene Period — had gone on steadily from strength to

204

EVOLUTION IN THE PAST

strength, or at any rate from size to size. This progress was
noticeable in the Pliocene, and, in the course of the Pleistocene,
the animals assumed in some cases colossal proportions.
Sloths raised upon their hind-legs were gathering foliage
twenty feet from the ground (Megatherium Americanum).
In order to take their meals in comfort, they doubtless
arranged the limbs and long bony tail in old Dinosaurian
style so as to constitute a sort of three-legged stool. Thus
seated they proceeded, we may suppose, to bend down the
tree-branches with their arms, and to tear off the foUage with
their long, curling tongues. Most of the time not spent in
eating was probably devoted to sleep. Some of them (Mylo-
don) possessed a certain amount of bony armour embedded
in the hide, and thus protected slept, no doubt, all the more
soundly.

Some imposing representatives of armadillo-life were
now on the scene in the form of gigantic glyptodonts. Daedi-
curus stands out as the most extraordinary of these. His
length from nose to tail-end was about twelve feet. The top
of his head was protected by a bony cap, and his body by a
rigid carapace. The tail, which contributed five feet to his
total length, was encased partly by rings of bone and partly
by a tube of like substance, enlarged and well-spiked at the
end. The tail, with its armour, must have been of immense
weight, and it is difficult to imagine that it ever left the
ground. Elaborate armature was, no doubt, a much-needed
protection to Daedicurus, for he was poorly endowed with
brains, phlegmatic in temperament, and probably wholly lack-
ing in courage.

Other glyptodonts were abroad that equalled Daedicurus
in total length, but they were longer in the body, and
shorter in the tail (Glyptodon clavipes). Their tails, moreover,
tapered to a point. It is not likely that the appendage
responded to happy sensations of head or heart, but it was
certainly more manageable than the heavy, battle-axe tail of
Daedicurus.

The peculiar South American hoofed animals had also
increased in stature. Toxodonts — in Miocene times looking as
though coneys had grown to the size of sheep — were now in

PLEISTOCENE PERIOD

20$

some cases as large as rhinoceroses (Toxodon). The guinea-
pig-shaped typotheres were also much bigger, some of the
animals having skulls a foot in length (T. cristatum). These
creatures had further converged to true rodents by the loss
of their canine teeth. Among the lama-like litoptems, forms
were now to be seen as large as camels (Macrauchenid). In
the Pliocene Period some of the litopterns were remarkable in
having the nasal aperture much higher up the skull than in
the earlier forms. This shifting process had been continued,
and the aperture was now located between the eyes. This
leads one to suppose that a short trunk had been evolved.
Macrauchenia, the typical form, was, so to speak, playing
many parts. In bodily shape and the length of the neck it
resembled a lama ; its limbs — the fore being longer than the
hind — were suggestive of a giraffe ; its head resembled in
structure that of a horse ; its proboscis that of a primitive
elephant ; its teeth, those of a rhinoceros ; whilst its feet
were much as those of the primitive three-toed horses.

There was thus in South America a remarkable medley of
animals savouring of primitive times in mammal evolu-
tion. The mosaic anatom}^ of Macrauchenia was quite out of
date. The dissipated constitution of toxodonts exhibited a
want of concentration almost as anachronic. Animals, small-
brained and heavily armoured — represented by glyptodonts —
had long been more or less condemned in other parts of the
world. Brain power had come well to the fore, and heavy
armour was being discarded. Had not man been evolved ? — a
well-brained creature with practically no armour to shield him
from his foes. It is, therefore, no matter for surprise that as
soon as South America became, as it were, opened up, a good
deal of the native fauna failed to hold its own. It was
victimised, in short, by what may be called mammal free
trade. Litopterns, toxodonts, typotheres, and glyptodonts
slowly passed away ; and are not known after this Period.
Carnivores from the north had, no doubt, much to do with this;
for to judge by the size of the " sabre-toothed " cats (Smilo-
don), and certain wolf-like animals (C. moreni), these brutes
were living well. Ground-sloths survived the other forms, for
they were certainly in existence when in later times man

2o6

EVOLUTION IN THE PAST

found his way to the continent. All ground-sloths, however,
have now gone to their long sleep — a condition for which
they were well prepared.

The " sabre-toothed " cats, big and bloated though they
had become in a land of plenty, were, however, now drawing
to their end. Carnivores better brained, and less enormously
tusked, such as jaguars and ocelots, were already in the
land ; and pumas were probably working their way down
from North America. " Sabre-tooths " had certainly had a
long and widespread career. Originating apparently in
Europe in the Oligocene Period, they had spread to Asia,
thence to North America, and were now making havoc among
the fauna of the Southern continent. Their end seems to
have been somewhat abrupt, as no trace is found of them in
any country after this Period. Professor Flower expressed an
opinion that the tusks ultimately became so inconveniently
long as to render it almost impossible for the animals to eat.
Creatures in such predicament, with palatable prey near but
not negotiable, bring to mind the fate of Tantalus.

Australia had long been cut off by the sea from the benefits
of what may be called advancing civilisation ; and her vast
territory of over 3,000,000 square miles was dominated by
marsupials. Here, far away from the "madding crowd," these
creatures had branched and re-branched in various directions ;
and whilst their relatives in other lands had sunk into utter
insignificance, they themselves were enjoying a golden age.

A great part of the island-continent was probably then,
as now, more or less desert in character ; but the coastal
regions, refreshed by heavy rains, doubtless abounded with
rich feeding grounds. And there is geological evidence that
some of the now arid central lands were in Pleistocene times
well watered and fertile.

Favoured in some districts by vegetation ample and
nutritious, the animals were of huge dimensions. Creatures
of wombat form, but as large as hippopotamuses (Diproto-
don), and kindred brutes, suggestive of tapirs overgrown
(Nototherium), testified to a prosperity continued through
many generations. Kangaroos with skulls nearly a yard in
length were here, looking as if some old bipedal dinosaurs had

MACRAUCHENIA

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PLEISTOCENE PERIOD

207

risen from earth glorified as mammals (Macropus titan),
Phalanger-like animals, as large as big bears and sometimes
termed " pouched lions," were also about the scenes (Thy-
lacoleo).

The prosperity of the vegetarians was naturally reflected
in the carnivores. Tasmanian "devils," or sarcophiles, were
abroad, much larger than their modern badger-sized repre-
sentatives (Sarcophilus). Pouched wolves prospered greatly
(Thylacinus) ; and — to judge by their teeth — the "pouched
lions," in addition to vegetables, indulged occasionally in
animal food (Thylacoled).

The fauna was rendered additionally grotesque by the
presence of gigantic birds, wingless and small-skulled. Some
of these carried their diminutive heads twelve feet up in the
air (Moa, Dinornis).

It might well be thought that by this time some of the
mammals would have developed into creatures of higher
grade. It must be concluded, therefore, that their remote
ancestors who invaded the land, and were then isolated by the
sea cutting off continental connections, were so far anatomi-
cally committed to marsupialism as to be inconvertible. It is,
however, interesting to note that the idea, if one may so
speak, worked out in the higher rank of mammals was more
or less expressed in Australia on the lower plane. An approach
to ungulates was evidenced in kangaroos, to rodents in
wombats, to insectivores and carnivores in " native cats "
and thylacines. And had marsupialism continued free to
develop, some pouched animals with resemblance to anthro-
poid apes, and even to human beings, might have appeared.

These prospects, however, were probably at an end as soon
as man invaded the island-continent. When this event took
place is quite unknown. The first arrivals were probably
wandering hunters from New Guinea. Savages of low type
they may well have been according to modern ideas ; but in
order to reach Australia they must have known how to
construct rafts or canoes. Indeed, they must long have had
some seafaring knowledge, for without it New Guinea could
not have been reached.

As to what race of men the invaders belonged opens up

208

EVOLUTION IN THE PAST

DISPERSAL the difficult question of the early dispersal of mankind. It is
OF MANKIND generally supposed that mankind originated on the mainland
of Southern Asia, formerly of vaster extent by the inclusion
of territory now submerged by the Arabian Sea. Owing to
increase of population a dispersal, in course of time, must
have taken place ; and men, brought under various climatic
and other conditions, gradually differentiated into three
groups, known as Negroid or Black, Mongolian or Yellow,
and Caucasian or White.
MIGRATION One migratory movement from the cradle-land pursued,
TO AUSTRALIA ^lo doubt, a south-easterly direction across the East Indian
Archipelago. In course of time some of the wanderers, it
may be supposed, reached New Guinea, and thence crossed
the Torres Strait to AustraHa. These emigrants, at the time
of their arrival in Australia, may not have been already
" blacks " ; but it is reasonable to assume that they were
well on the way to becoming so.

In the opinion of many, the Tasmanians, who became
extinct in 1876, were descendants of the men that first
reached Australia. Their presence in Tasmania was caused,
it is supposed, by their ancestors having been gradually
forced south by the arrival in Australia of a second Asiatic
horde or race. These second invaders — blended possibly with
some of the earlier race — are now represented, it is thought,
by the Australian aborigines.

These migrations did not bring any laurels to humanity.
The Tasmanians never showed any signs of becoming civil-
ised ; and the Australian aborigines are the lowest of savages.
Indeed, it is doubtful if they are in a much higher state of
culture than were the inter-glacial hunters. The cause is not
far to seek. By long isolation the animal Hfe of Australia had
remained in a lowly condition of development ; and so the
aborigines of old, away from " the great world," with its
denser populations, and keener competitions, lost all share in
its evolving civiHsation.
MIGRATIONS Another migration from the cradle-land led to the peophng
TO CENTRAL of Africa south of the Sahara. These wanderers, coming
AND SOUTH- across the land now submerged by the Arabian Sea, spread
ERN AFRICA over various districts of the " dark " continent, and gave

DIFROTODON
A gigantic wombat living in Australia in the Pleistocene Period

[To face page soS

PLEISTOCENE PERIOD

209

rise in time to many scattered tribes and races of negroids.
But it cannot be said that any of these ever adorned humanity.
The conditions, owing to the vastness of the land area, and
the nature of the climate, were not, it may be supposed,
sufficiently stimulating.

In the more enclosed and salutary regions to the north of migrations
the Sahara more important movements were in progress, to north
From the quantities of palaeoUthic implements found in the Africa
ancient limestone and gravel formations of Egypt, it is
clear that that country was occupied in Pleistocene times,
and probably very much earlier. The Pleistocene Egyptians,
no doubt, had become very different from their fellow-
creatures south of the Sahara. Indeed, they may well have
become so far differentiated as to be describable as primitive
members of the Caucasian or White group — destined to great
fame in times to come. How long these " dark whites "
remained in Egypt cannot be determined ; but doubtless
they were driven in course of time along the coastal regions of
North Africa by other and more civilised " dark whites,"
sweeping into Egypt from the East. In occupying Egypt
they themselves, no doubt, had driven on less civiUsed tribes
along the coasts in the direction of Tunis, Tripoli, Algeria,
and Morocco. And it was probably under this more or less
constant pressure of emigration from the east that the
inter-glacial hunters and the Cave men had been forced along
the coast, until in time they crossed from Africa to Europe
by one of the old and long since submerged land connections.

Another migration from the cradle-land led to the occupa- migrations
tion of China and Siberia ; and the differentiation of the to central
Yellow group of races. It was, doubtless, an offshoot of this and north-
migration which brought the " new " world its first human ern Asia,
beings. and to

Unfortunately but little is known as to how humanity America
was faring in the cradle-land during Pleistocene times.
In the alluvial plains of the Tigris and Euphrates, fertile the cradle
soil and abundance of food must have led many people to live land
not as scattered and wandering families, but in tribal settle-
ments. And a civiUsation must have been forming, which
had, as yet, been but faintly reflected in Europe,
p

210

EVOLUTION IN THE PAST

Of this higher civilisation Egypt was undoubtedly an
outpost ; but it was not from that quarter that Europe was
to derive her vigorous races.
EUROPE AT Before the close of the Period the climate of Europe became
CLOSE OF so warm as to drive mammoths, woolly rhinoceroses, and
PLEISTOCENE other hardy animals to distant scenes. Lions, leopards, and
jungle-cats multiphed on the continent ; and hippopotamuses
and straight-tusked elephants {E. antiquus) penetrated far
into Britain, which still formed part of the European main-
land. The high temperature, however, was not greatly
prolonged ; and the warm-climate animals gradually with-
drew to more congenial scenes, excepting the straight-tusked
elephants {E. antiquus), which appear to have become
extinct.

QUATERNARY AGE

PRESENT PERIOD

The climate of Europe had now settled down to much as
it is at the present day ; and the same may broadly be said of
the fauna and the vegetation. This state of things may date
back fifty thousand years or more ; but until historic times
are reached all dates are conjectural.

No trace, artistic or otherwise, is to be found in this Period
of the Cave men. Some of them may have been absorbed
by new invaders of Europe. In any case pictorial art on
the continent had declined ; for the artist-work of the
new lords of the soil was far inferior to that of the " old
masters."

The earliest chronicles that have been found of man in DANISH
Europe in the Present Period consist of the ancient shell- shell-
mounds of Denmark. On the coasts of Jutland, and along mounds
some of the fiords of Zealand, men were living in more or less
permanent settlements. The fact best recorded about these
people is that they were great consumers of oysters, cockles,
mussels, and periwinkles. From the size of the shells it is
evident that the molluscs were in "fine" condition; and
it may be presumed that the Baltic waters then contained
more salt than now.

These settlers, however, did not subsist entirely on molluscs.
They were also lovers of pork and venison. In the neigh-
bouring forests numbers of wild boar, red deer, and roe deer
fell to their skill and cunning. In the art of hunting they
certainly surpassed the Cave men, as they possessed dogs
of a jackal type trained to be of service in the chase. Their
diet was further varied by fish and fowl ; and there is evidence
that the wild swan and the great auk occasionally enriched

212

EVOLUTION IN THE PAST

their repasts. There is no reason to suppose that they ever
cultivated the soil.

Weapons and implements they had in plenty ; but although
these in a few cases were poUshed, and, therefore, of neolithic
or " new stone " type, they were as a rule little superior to
those of the Cave men. Pottery, roughly made, was certainly
in use. This is a luxury which, it is believed, the Cave men
did not possess.

Unfortunately no human remains have been found in the
shell-mounds. There are numerous burial-mounds, belonging
to a round-headed race of men, in the neighbourhood, but
none of these can be assigned definitely to the consumers of
the molluscs.

The domestication of the wild dog is a fact of the highest
significance. Indeed, the discovery — made many thousands
of years ago — that wild animals could be brought into man's
service is one of the greatest triumphs in the history of
mankind. The mollusc-eaters, it may safely be said, did
not make the discovery, nor had they put it much in practice.
Doubtless it had originated, and had already been considerably
developed, in the East, where also other highly important
discoveries had been made.
EARLY LAKE- Among the many tribes that were arriving in Europe,
DWELLERS whilst the mollusc-eaters were enjoying life in Denmark,
some certainly had not only jackals in a domesticated con-
dition, but also goats and oxen. Nor were these men merely
wandering shepherds and graziers ; for there is evidence that
at least some of them cultivated the soil, and raised crops of
wheat, barley, and millet.

Some of these agriculturists, as may be gathered from the
evidence of the earliest lake-dweUings of Switzerland, Uved
on the borders of lakes in rude huts, resting on piles driven
into the mud. This peculiar kind of habitation was adopted,
it may be supposed, as a protection from wild beasts
and incursions of hostile tribes. It was certainly much
in use, and greatly elaborated in later times. Even the
earUest lake-dwellers did not wholly rely on skins for
their clothing, for they were acquainted with the art of
spinning. This, as well as their pottery, rudely manufac-

PRESENT PERIOD

213

tured though it was, testified to a well-advanced standard
of culture.

The mollusc-eaters and the lake-dwellers both probably
came more or less directly from the East, having worked
their way up the valley of the Danube. And they were doubt-
less forerunners of that division of the White or Caucasian
group, known in history as Aryans.

Other very distantly related tribes came in time from SEMITICS
Africa, having availed themselves of the land connection
which obtained on the site of the Strait of Gibraltar. These,
it is supposed, were a dark-skinned people, belonging to the
Semitic division of the Caucasian group. And there is little
doubt that they had been pushed on by the great migratory
movements that had been proceeding along the coast-lands of
northern Africa.

These men do not seem to have settled to any great extent
in the north of Europe, but they became numerous in Spain
and France. Like the early lake-dwellers, they tilled the soil,
but they were in a higher state of culture than those men.
They were well acquainted with the art of grinding and
pohshing stone implements, and were certainly, therefore,
in what is known as the neolithic or new stone age of culture.
They were also, it would seem, in possession of bows and
arrows. Their domestic animals consisted of dogs, horses,
oxen, goats, and deer. And they were well acquainted with
spinning, and with the potter's art.

In addition to these accomplishments, they were able to
construct canoes ; and this enabled some of the more adven-
turous spirits to visit Britain — separated at this time from
the mainland.

They buried their dead in regular graves — a practice not
pursued, so far as is known, by the mollusc-eaters and the
early lake-dwellers. As they deposited various articles in the
tombs, they believed probably in an after-life, more or less
occupied with human pursuits.

The warlike Silures, who so long resisted the Roman arms
in Britain, were, it is supposed, descendants of these
swarthy tillers of the soil. And the latter are probably still
represented in Europe by the Basques of France and Spain.

214

EVOLUTION IN THE PAST

Some Welshmen of to-day may also be inheritors of the
blood.

KELTS Successive waves of emigration from Asia brought in
time various so-called Keltic tribes to Europe, and a know-
ledge of bronze. But here we must draw to a close. Indeed,
while the dark-skinned agriculturists from Africa were
bringing new ideas to Europe, historic times were beginning
to run at least in Egypt. For on that long-trodden soil in
4400 B.C. — more than two thousand years before the time of
Abraham — Menes founded a dynasty. And there he reigned
over a well-civilised people, until a hippopotamus brought
his rule abruptly to an end.
DECLINE OF The Undignified death of the monarch was not portentous
BRUTE-LIFE of a turn in the fortunes of brute-life. Indeed, that life
had long been steadily declining, and it continued to do so.
This decline commenced probably in the Pliocene Period, was
accelerated in the Pleistocene, and has continued ever since.
To-day brute-Ufe, except in a domesticated condition, is at
a very low ebb. This long-continued downward course is
doubtless in part ascribable to climatic changes and disease ;
but in its later stages it has beyond question been brought
about chiefly by man. The helplessness of wild-brute life has
been forcibly brought out of late. In some territories wild
beasts only continue to exist owing to Government
protection.

How great the fall has been may also be gathered from
the present distribution and condition of some famiUar
animals. Elephants, at one time consisting of many species,
were prosperous in Europe, Asia, Africa, and North and
South America. Now they are reduced to one African and
one Indian species. As the family has shown itself wilUng
enough and able to co-operate with man, the majestic old
line may long continue. Rhinoceroses, once ranging freely
over several continents, are now known only in restricted
areas of Africa, India, and the Malayan countries. Their
range, too, is bound to diminish, for the animals have no
stomach for civilisation, and are never likely to be seen
drawing the plough, or otherwise toiling in man's service.
Camels exist no longer in a truly wild state. Tapirs, once

PRESENT PERIOD

215

dwellers in Europe, Asia, and both continents of the new
world, are to-day found only in isolated districts of Central
and South America, and the Malayan countries. Horses
in a wild state exist only on the arid plains of Central Asia,
and are rapidly approaching extinction. Zebras, resentful
of domestication, lead precarious lives in parts of Africa.
The closely allied Quagga has recently become extinct. Wild
asses have sought safety in sandy deserts, or amid mountain
snows, in Africa and Asia. Lions, leopards, and other
ferocious carnivores are being rapidly exterminated ; and a
like fate is overtaking the innocuous giraffe. Man-like apes
at the present time possess very limited territories, and are
ending their days in strict retirement. Orangs and chim-
panzees flourished in India, and probably in many other parts
of Asia, in Pliocene times. The former are now found only
on the islands of Borneo and Sumatra ; and chimpanzees
are restricted to equatorial forests in Africa. Gibbons alone
survive in south-eastern Asia. Gorillas — the most man-like
of the apes — have found a last retreat on the west coast
of Africa in French Congo territory.

Man meanwhile has made a wonderful progress. Master of
brute-life, he has also acquired no small control over the
blind forces that pervade the universe ; and in various other
ways he has travelled far from a purely animal condition.
It cannot, however, yet be said that he has gained complete
mastery of the brute passions and impulses which he has
inherited from a remote past. The achievement of this, so far
as can be seen, is an immediate purpose in his further evolu-
tion.

AUTHORITIES CONSULTED

ABBREVIATIONS

A.A.A.S.

American Association for Advancement of Science.

A.B.

Annals of Botany.

A.M.N.H.

American Museum of Natural History (publications)

A.N.

American Naturalist.

A.N.H.

Annals and Magazine of Natural History.

B.A.

British Association for Advancement of Science.

B.G.

Botanical Gazette.

B.M.

British Museum.

CM.

Century Magazine.

C.N.H.

Cambridge Natural History.

E.B.

Encyclopaedia Britannica.

G.A.

Geological Association.

G.M.

Geological Magazine.

I M

LVl lid Lll^iiCll JlTXUII LJLU. y .

J.L.S.

Journal Linnean Society.

L.T.Z.

Sir E. Ray Lankester's " Treatise on Zoology."

Nature.

N.P.

New Phytologist.

N.S.

Natural Science.

Palaeontographica.

P.L.S.

Proceedings Linnean Society.

P.M.S.

Proceedings Malacological Society.

P.S.M.

Popular Science Monthly.

P.T.R.S.

Philosophical Transactions of the Royal Society.

QJ.G.S.

Quarterly Journal of the Geological Society.

R.M.S.

Royal Microscopical Society.

217

2l8

EVOLUTION IN THE FAST

R.P.S.
S.T.Z.
T.R.S.E
T.Z.S.

Reports Palaeontographical Society.
Sedgwick's " Text Book of Zoology."
Transactions Royal Society, Edinburgh.
Transactions Zoological Society.

U.S.G.S. United States Geological Survey (publications).
Z.T.P. Zittel's " Text-book of Palaeontology."

Abbot, Miss. P.T. 1895.

Ameghino, F. Mamiferos de la Republica Argentina. 1889.
Amalitzky, W. (Warsaw) . See page 62.

Andrews, C. W. Catalogue of Tertiary Vertebrata of the Fayum,
Egypt. B.M. 1906.
Systematic Position of Moeritherium. N. September 9, 1909.
Evolution of the Proboscidea. P.T.R.S. 1903.
A Descriptive Catalogue of the Marine Reptiles of the Oxford
Clay (Part I). B.M. 1910.
Arber, E. A. Newell. Origin of Angiosperms. J.L.S. July, 1907.

Fossil Plants, 60 photographs of Flora of Coal Measures. 1909.
Avebury, Lord. Prehistoric Times. 1900.

Balfour, Francis M., and Foster, M. Elements of Embryology. 1902.
Bateson, W. Materials for the Study of Variation. 1894.

Mendel's Principles of Heredity. 1909.
Bather, F. A. The Echinoderma. L.T.Z. 1900.

British Fossil Crinoids. A.N.H. 1890-92.
Baur, G. The Stegocephali. Anat. Anzeiger. 1896.
Beadnell, H. J. L. See pp. 124, 129.
Beddard, F. E. Mammaha. C.N.H. 1902.

Structure and Classification of Birds. 1898.
Beecher, C. E. Collaborator, Trilobites. Z.T.P. 1900.
Bonney, T. G. The Story of our Planet. New edition, 1898.
Boulenger, G. A. Fishes (Teleostei). C.N.H. 1904.
Bourne, G. C. Anthozoa, and Ctenophora. L.T.Z. 1900.
Bower, F. O. Origin of a Land Flora. 1908.

Brongniart, C. Recherches pour servir a I'histoire des insectes fossiles.
1894.

Caiman, W. T. Crustacea. L.T.Z. 1909.

AUTHORITIES CONSULTED

219

Campbell, Douglas. Evolution of Plants. 1902.

Carpenter, P. H. Catalogue of Blastoidea. B.M. 1886 (pars.).

Morphology of Cystidea. J.L.S. 1894.
Case, E. C. Revision of the Pelycosauria of North America. 1907.

A Great Permian Delta. P.S.M. December, 1908.

Revision of Amphibia. Z.T.P. 1902.
Chamberlin, T. C. (University of Chicago), and Salisbury, R. D.

(University of Chicago). Geology. 1906.
Clarke, J. M. Part-collaborator, Crustacea. Z.T.P. 1900.
Claus, C. Text-book of Zoology, trans, by Adam Sedgwick. Vol. I,

4th ed., 1892. Vol. II, 1897.
Cooke, A. H. Molluscs. C.N.H. 1895.
Cope, E. D. Primary Factors of Organic Evolution. 1896.

Condylarthra, Amblypoda, Creodonta. A.N. 1884.

Vertebrata of the Tertiary Formations of the West. U.S.G.S.
1884.

Crick, G. C. Belemnites. P. M.S. 1896, 1907.

Dall, W. H. Collaborator, Pelecypoda. Z.T.P. 1900.
Dana, J. D. Manual of Geology. 4th ed., 1895.
Darwin, Charles. Origin of Species (first published 1859).

Descent of Man (first published 1871).
Davidson, T. British Fossil Brachiopoda. R.P.S. 1851-86.

Recent Brachiopoda. J.L.S. 1886-8.
Dawkins, W. Boyd. Early Man in Britain. 1880. Cave-Hunting.
1874.

Dawson, Sir J. W. Geological History of Plants. 1888.
Dendy, A. Origin of Vertebrates. P.L.S. October, 1910.
Deperet, C. Transformations of the Animal World. 1909.
de Vries, Hugo. Die Mutationstheorie. Leipzig. 1902.

Species and Varieties. Their Origin by Mutation. 1895.
Dubois, E. Pithecanthropus erectus. Batavia. 1894.
Duckworth, W. L. H. Morphology and Anthropology. 1904.

Eastman, Charles R. (Harvard College, U.S.A.). Translator and
Editor Zittel's Text-book of Palaeontology (Vol. I, Inverte-
brates, 1900. Vol. II, Fishes, Amphibians, Reptiles, Birds,
1902. Vol. Ill not yet published).

220

EVOLUTION IN THE PAST

EUes, G. L, British Graptolites. R.P.S. 1901-8.
Etheridge, R. Catalogue of Blastoidea. B.M. 1886 (pars.).
Ettingshausen, C. B. British Eocene Flora. R.P.S. 1879, 1880, 1882.
Evans, A. H. Birds. C.N.H. 1900.

Ewart, J. Cosser. Possible Ancestors of Horses living under Domesti-
cation. G.M. August, 1909.
The Celtic Type of Horse. N. 1903, p. 239.

Falconer, H. Palaeontological Memoirs. 1868.
Farmer, J. B. Part-collaborator, Protozoa. L.T.Z. 1903.
Flower, W. H., and Lydekker, R. Mammals Living and Extinct.
1891.

Foster, M., and Balfour, F. M. Elements of Embryology. 1902.

Physiology, General View. E.B.
Fowler, G. H. The Hydromedusae, and Scyphomedusae. L.T.Z.
1900.

Fraas, E. Die Meer-Crocodilier. P. 1902.

Gadow, Hans. Amphibia and Reptiles. C.N.H. 1901.
Gamble, F. W. Part-collaborator, Protozoa. L.T.Z. 1901.
Gardiner, Stanley. P.L.S. October, 1910.

Gardner, J. S. British Eocene Flora. R.P.S. 1879, 1880, 1883,
1884, 1886.

Gaskell, W. H. Origin of Vertebrates (1908), and discussions thereon

at meetings of the Linnean Society. P.L.S. October, 1910.
Gaudry, Albert. Les Enchainements du Monde Animal. 1878-90.
Gegenbaur, Carl. Vergleichende Anatomic der Wirbelthiere. 1898.
Geikie, Sir A. Text-book of Geology. 4th ed., 1903.
Geikie, J. The Great Ice Age. 4th ed., 1903.

Prehistoric Europe. 1881.
Goodrich, E. S. Cyclostomes and Fishes. L.T.Z. 1909.

Origin of Vertebrates. P.L.S. October, 1910.
Gregory, J. W. British Palaeogene Bryozoa. T.Z.S. 1893.

Catalogue of Fossil Bryozoa. B.M. 1896, 1899.

Palaeozoic Ophiuroidea. P.Z.S. 1896.
Giinther, A. Study of Fishes. 1880.

Haeckel, Ernst. History of Creation. Trans, by Ray Lankester.
4th ed., 1899.

AUTHORITIES CONSULTED

221

Evolution of Man. 1883.

The Last Link. 2nd ed., 1899.
Harmer, S. F. Joint-Editor Cambridge Natural History. 1895-1909.

Polyzoa. C.N.H. 1901. Hemichordata. C.N.H. 1904.
Hartog, M. Protozoa. C.N.H. 1906.
Hatcher, J. B. Part-collaborator, Reptiles. Z.T.P. 1902.
Hay, O. P. (American Museum of Natural History, New York.)

Part-collaborator, Reptiles. Z.T.P. 1902.
Heer, 0. Primeval World of Switzerland. Ed. by J. Heywood. 1876.
Heilprin, A. The Distribution of Animals. 2nd ed., 1894.
Herdman, W. A. Phylogenetic Classification of Animals. 1885.

Ascidians and Amphioxus. C.N.H. 1904.
Hickson, S. J. Coelenterata and Ctenophora. C.N.H. 1906.

Part-collaborator, Protozoa. L.T.Z. 1903.
Hinde, G. J. Catalogue of Sponges. B.M. 1883.

British Fossil Sponges. 1887-93.

Collaborator, Vermes. Z.T.P. 1900.
Holland, W. J., Director of the Carnegie Museum, Pittsburg, U.S.A.

Carnegie Museum publications.
Hutchinson, Rev. N. Extinct Monsters and Creatures of Other Days.

New and enlarged edition, 1910.
Huxley, P. H. Man's Place in Nature, 1860-63.
Hyatt, A. Collaborator, Cephalopoda. Z.T.P. 1900.

IngersoU, E. Life of Mammals. 1906.

Johnston, Sir Harry. See page 170.

Joly, N. Man Before Metals. 5th ed., 1892.

Jukes-Browne, A. J. Stratigraphical Geology. 1902.

Kayser, E. Text-book of Comparative Geology. Translated and

edited by P. Lake. 2nd ed., 1895.
Keane, A. H. Man Past and Present. 1900. Ethnology. 1901.
Kellogg, V. L. Darwinism To-day. 1907.
Kingsley, J. S. Part-collaborator, Crustaceans. Z.T.P. 1900.
Lake, P. See Kayser.
Lang, W. D., see Preface.

Lankester, Sir E. Ray. Editor of Treatise on Zoology (in course of
publication).

222

EVOLUTION IN THE PAST

Extinct Animals, ist ed., 1905.
Zoology. E.B.

Origin of Vertebrates. P.L.S. October, 1910.
Lapworth, C. British Graptolites. R.P.S. 1901-8.
Lister, J. J. Foraminifera. L.T.Z. 1903.

The Arthropods. S.T.Z. 1909.
Lock, R. H. Variation, Heredity, and Evolution. 1906.
Lucas, F. A. (Washington Museum). Revision of Aves. Z.T.P. 1902.

Animals of the Past. 1901.
Lydekker, R. Catalogue of Fossil Mammalia. B.M. 1885-7.

Catalogue of Fossil Reptiha and Amphibia. B.M. 1888-90.

Catalogue of Fossil Birds. B.M. 1891.

Mostly Mammals. 1903.

Geographical Distribution of Mammals. 1896.
Editor of The Royal Natural History. 1894-6.
Extinct Edentates and Ungulates of Argentina. 1894.
(With Nicholson) Manual of Palaeontology. 3rd ed., 1889.
(With Flower) Mammals Living and Extinct. 1891.
Lyell, Sir C. Principles of Geology. 12th ed., 1875.
Antiquity of Man. 4th ed., 1873.

MacBride, E. W. Echinodermata. C.N.H. 1906.

Origin of Vertebrates. P.L.S. October, 1910.
Marsh, O. C. The Dinocerata. 1884.

Introduction and Succession of Vertebrate Life in America.

A.A.A.S. 1878.
The Dinosaurs of North America. U.S.G.S. 1896.
Matthew, W. D. Fossil Mammals in Tertiary of Colorado. A.M.N.H.
1901.

Puerco Fauna. Bull. A.M.N.H. 1897.
Mendel, G. J., referred to, page 4.

Milne-Edwards, A. Oiseaux Fossiles. Paris. 1867-71.
Minchin, E. A. Sponges ; and collaborator. Protozoa. L.T.Z.
Mitchell, P. Chalmers. Origin of Vertebrates. P.L.S. October, 1910.
Morgan, C. Lloyd. The Interpretation of Nature. 1905.
Moodie, Roy L. (Kansas University, U.S.A.) The Microsauria.
G.M. May, 1909.

Neumayr. M. " Erdegeschichte." (New impression, 1897.)

AUTHORITIES CONSULTED

223

Newton, R. B. See Preface.

Nicholson, H. A. (with Lydekker). Manual of Palaeontology. 1889.

O'Harra, Cleophas C. Badland Formations of the Black Hills Region.

South Dakota School of Mines. Bulletin, November, 1910.
Oliver, F. W. Pteridosperms and Angiosperms. N.P. igo6.
Osborn, H. Fairfield, Professor Columbia University, Curator of Ver-
tebrate Palaeontology, American Museum of Natural History.
Rise of the Mammaha in North America. A.A.A.S. 1893.
The Ancylopoda. A.N. 1893.

The Evolution of the Horse in America. CM. November, 1904.
Hunting the Ancestral Elephant. CM. October, 1907.
Ichthyosaurs. CM. 1905.

The Dinosaurs of the Bone-Cabin Quarry. CM. September,
1904.

Collaborator on Reptiles. Z.T.P. 1902.
The Age of Mammals. 19 10.
Owen, R. Palaeontology. 2nd ed., 1861.

Parker, T. Jefferey. Elementary Biology. 3rd ed. reprinted 1900.
Parkin, John. Origin of Angiosperms. J.L.S. July, 1907.
Pelseneer, P. Mollusca. L.T.Z. 1906.
Pilsbry, H.A. Collaborator, Gastropoda. Z.T.P. 1900.
Poulton, E. B. Essays on Evolution. 1908.

Pycraft, W. P. Archaeopteryx. N.S. October, 1893. March and
April, 1894. December, 1895.
Story of Reptile Life. 1895.
A History of Birds. 1910.

Reed, F. R. C. Brachiopods (Fossil). C.N.H. 1895.
Ridgeway, W. Origin and Influence of the Thoroughbred Horse.
1905.

Salisbury, R. D. (University of Chicago), with T. C. Chamberlin.

Geology. 1906.
Salter, J. W. British Trilobites. R.P.S. 1864-83.
Saporta, Le Comte. Le Monde des Plantes. 1879.

(And A. F. Marion) L'Evolution du Regne vegetal. 1885.
Sargant, Miss Ethel. Early History of Angiosperms. B.G. 1905.
Scharff, R. F. History of the European Fauna. 1899.

224

EVOLUTION IN THE PAST

Schlosser, Max. See page 127.
Schmidt, O. Mammalia. 1886.

Schoetensack, Otto, Der Unterkiefer des Homo Heidelbergensis.

Leipzig. 1908.
Schubert, C. Collaborator, Brachiopoda. Z.T.P. 1900.
Schwann, Theodor. Microscopic Investigations in the Structure of

Plants and Animals, 1839. English trans., 1847.
Scott, Dukinfield H. Studies in Fossil Botany. 2nd ed., 1909.

" What were the Carboniferous Ferns ? " Address R.M.S. 1905.

The Flowering Plants of the Mesozoic Age. Address R.M.S. 1907.
Scott, William B. Introduction to Geology. 2nd ed., 1909.

Evolution of the Mammalia. I.M. 1901.

Editor of Reports Princeton Expeditions to Patagonia. 1901-11.
Scudder, S. H. Fossil Insects of the World. U.S.G.S. 1891.

Fossil Insects of North America. 1890.
Sedgwick, Adam. Text-book of Zoology. 1898-1909.
Seeley, H. G. Ornithosauria. 1870.

Seward, A. C. Fossil Plants. Vol. I, 1898. Vol. II, 1910.

Catalogue of Mesozoic Plants. B.M. 1895.
Sharp, D. Insects. C.N.H.

Shipley, A. E. Joint Editor Cambridge Natural History. 1895-
1909. Brachiopods (Recent). C.N.H.
Insecta and Arachnida. S.T.Z. 1909.
Sinclair, F. G. Myriapods. C.N.H. 1901.

Sladen, W. P. Collaborator, Asterozoa, Echinozoa. Z.T.B. 1900.
Smith, Geoffrey. Crustacea. C.N.H. 1909.
Sollas, I. B. J. Porifera. C.N.H. 1906.

Sollas, W. J. Silurian Echinoidea and Ophiuroidea. Q.J.G.S. 1899.
Spencer, Herbert. Principles of Biology (first published 1864-7).
Starling, E. H. P.L.S. October, 1910.

Stebbing, Rev. T. R. R. Amphipoda (Challenger Report). 1888.

Crustacea (Int. Sc. Series, Vol. LXXIV).

Essays on Darwinism. 1871.
Sternberg, C. H, Life of a Fossil Hunter. New York, 1909.
Stopes, Miss M. C. Ancient Plants. 1910.

Suess, Eduard. Das Antlitz der Erde. Trans. (1904-8) by Hertha
Sollas.

AUTHORITIES CONSULTED

225

Thomson, J. Arthur. Outlines of Zoology. New edition, 1910.

Heredity. 1908. See also Weismann.
Traquair, R. H. Fossil Fishes. T.R.S.E. 1881.

Extinct Vertebrata of Moray Firth Area. 1896.

Ulrich, E. O. Collaborator, Bryozoa, Ostracoda. Z.T.P. 1900.

Wachsmuth, C. Collaborator, Crinoidea, Blastoidea. Z.T.P. 1900.
Walcott, C. D. Fossil Medusae. U.S.G.S. 1898.
Wallace, A. Russel. Darwinism. 1889.

Speech Darwin-Wallace Celebration Lin. Soc. 1908.
Walther, J. Geschichte der Erde und des Lebens. 1908.
Weismann, August. The Evolution Theory. Trans, by J. Arthur

Thompson and Margaret R. Thompson. 1904.
Weldon, W. F. R. Crustacea (pars.). C.N.H. 1909.
Wiedersheim, R. Structure of Man. Trans, by H. and M. Bernards

1895.

Wieland, G. R. American Fossil Cycads. 1906.

Williston, S. W. (Kansas University, U.S.A.). Part-collaborator,

Reptiles. Z.T.P. 1902.
Wood, E. M. R. British Graptolites. R.P.S. 1901-8.
Woods, Henry. Palaeontology (Invertebrate). 4th ed., 1909.

Trilobites and Eurypterids. C.N.H. 1909.
Woodward, Arthur Smith. Vertebrate Palaeontology. 1898.

Catalogue of Fossil Fishes. B.M. 1889-1901.

Modern Methods in the Study of Fossils. Pres. Ad. G.A. 1905.

Relations of Palaeontology to Biology. Ad. Int. Con. St. Louis,
U.S.A., September, 1904.

Evolution of Fins. N.S. 1892.

Revision of Fishes. Z.T.P. 1902.

Study of Fossil Fishes. Pres. Ad. G.A. February, 1906.
Address to Geological Section B.A. 1909.
Origin of Vertebrates. P.L.S. October, 1910.
Woodward, Henry. Catalogue British Fossil Crustacea. B.M. 1877.
Crustacea. E.B.

Some Coal-Measure Crustaceans and Modern Representatives.

G.M. December, 1908.
Some Ideas on Life. Pres. Ad. R.M.S. January, 1903.

226

EVOLUTION IN THE PAST

Evolution of Vertebrate Animals in Time. Pres. Ad. R.M.S.
January, 1904.

Further Notes on Arthropoda of Coal-Measures. G.M. Decem-
ber, 1907.

The Merostomata. R.P.S. 1866-78.
Wright, G. F. Man and the Glacial Period. 2nd ed., 1893.
Zittel, K. A. von. Handbuch der Palaeontologie. 1876-93.

English Edition. See Eastman.

GENERAL INDEX

Aard-varks, 141
Abdominal ribs, 61
Acentrophorus, 64
Actinopterygian Ganoids —

Devonian, 41

Carboniferous, 58

Permian, 64

Triassic, 75

Jurassic, 87

Cretaceous, 105

Eocene, 136
Africa, 119, 208
Agriculture, 212, 213
Albatross, 131
Alcyonarians, 21, 110
Algae, 8, 15, 20
Alligators, 1 01, 134
Almond trees, 154
Alps, 138, 168
Alticamelus, 158
Amber, 152
Amblypods, 117, 122
America, North, passim —

Pliocene, Earlier, 180

— Later, 184

Pleistocene, 191, 192, 201
America, South —

Miocene, 161

Pliocene, 181, 185

Pleistocene, 202
Amia, 76

Ammonites, 44, 67

{See also Ammonoids)
Ammonoids —

Devonian, 43

Carboniferous, 56

Permian, 67

Triassic, 74

Ammonoids (cont.) —

Jurassic, 85

Cretaceous, 107

Eocene, 137
Amphibians —

Carboniferous, 58

Permian, 61

Triassic, 76

Jurassic, 89

Eocene, 135

Oligocene, 140

Miocene, 167

Ancestry of, 59
Amphicyon, 146, 156
Amphineura. See Chitons
Amphioxus. See Lancelets
Amphipods, 35
Anaspides, 57
Anchisaurus, 78
Anchitherium, 159
Ancylopods, 140, 171
Angiosperms, 89, 112
Annelids, 14

Anomodonts. See Theromorphs
Anoplotheres,i28, 144, 157
Ant-eaters, 185
— Scaly, 141
Antelope —

Miocene, 158

Pliocene, 169, 178, 183

Elands, 169, 178

Gazelle, 169

Harnessed, 169

Hartebeest, 178

Kudus, 169, 178

Nilgai, 178

Oryx, 169

Sable, 169, 178

Saiga, 194

Waterbuck, 178
Anthozoa, See Corals

227

228

EVOLUTION

IN THE PAST

Anthracosaurus, 59
Anthrocotheres, 128, 144, 176
Anthropoids. See Apes and generic

names
Ants, 89

Anura. See Frogs, Toads
Apes —

Eocene, 127

Oligocene, 149

Miocene, 154, 164

Pliocene, 172, 179, 184

Present, 215

Baboons, 155, 179

Chimpanzee, 155, 179

Dryopithecus, 155

Gibbon, 155

Gorilla, 155, 179

" Holy," 172, 179, 184

" Howler," 164

Langur. See " Holy "

Macaques, 172, 179, 184

Mesopithecus, 172

Orangs, 179

Pliopithecus, 155

Propliopithecus, 127

Semnopithecus, 172
Apus, 19

Arachnida. See Scorpions, Spiders
Araucaria, 68, 70, 88
Archaeopteryx, 2, 96
Ark-shells, 18, 55, 66, 73
Armadillos —

Eocene, 124

Miocene, 162

Pliocene, 181, 185

Pleistocene, 204
Arsinoitherium, 129
Art, 200, 211
Arthrodirans, 39

Arthropods. See Crustaceans, Insects,
King-crabs, Myriapods, Scorpions,
Sea-scorpions, Spiders, Trilobites
Ancestral, 3

Aryans, 213

Asaphus, 26

Asia, Glaciation, 190

Aspidorhynchus, 88

Asses, wild, 215

Asteroids. See Starfishes

Astrapotheres, 163, 185

Atlantosaurus, 90, 98

Auks, 166

Australia, 165, 186, 206

— aborigines of, 208

— arrival of man in, 207

Baboons. See under Apes
Bactrites, 43, 56
Baculites, 107
Badgers, 174, 194
Balanoglossus, 3
Barnacles —
Cambrian, 19
Ordovician, 26
Jurassic, 86
Cretaceous, 107
Basques, 213
Bats, 126

Beach-fleas. See Amphipods
Bears —

Oligocene, 146

Miocene, 156

Pliocene, Earlier, 173, 174

— Later, 184

Pleistocene, 190, 192, 194

Cave, 190, 194

Polar, 192

Sloth, 174
Beavers, 148, 155
Beaver-squirrels, 156, 180
Bees, 89, 152
Beetles, 71, 89, 152
Belemnites —

Triassic, 74

Jurassic, 86

Cretaceous, 107

Eocene, 137

Ancestry, 74
Belodon, 77

Bennettiteae, 71, 89, 113

Berycoids, 106

Birds-
Jurassic, 96
Cretaceous, iii
Eocene, 131
Oligocene, 150
Miocene, 166
Ancestry, 2, 96

{See also under various names.)
Birkenia, 36
I Bison, 178, 200

INDEX

229

Bivalves. See Pelecypods
Blastoids,

Silurian, 30

Devonian, 46

Carboniferous, 54
Blastosphere, 10
Bone, 36, 64
Bony pike, 88
Bot-flies, 152

Bovidae. See Antelope, Bison, Goats,

Oxen, Sheep
Brachiopods —

Cambrian, 18

Ordovician, 23

Silurian, 3 1

Devonian, 45

Carboniferous, 54

Permian, 66

Triassic, 72

Jurassic, 84

Cretaceous, 109

Eocene, 137

Ancestry, 14

Zenith, 32
Bream, 106 J

Britain, separation of, 213
Brittle-stars —

Ordovician, 23

Silurian, 3 1

Devonian, 45

Carboniferous, 54

Permian, 66

Jurassic, 83
Brontops, 141
Brontosaurus, 90
Bronze, 214

Brute life, decline of, 214
Bryozoans. See Polyzoans
Bumble bees, 152
Burial, 190, 213
Bustards, 151
Butterflies, 152
Buzzards, 132, 151'

Calamaries, 86
Calamites. See Equisetales
Calymene, 26
Cambrian Period, 16

Camels —

Eocene, 129

Oligocene, 145

Miocene, 158

Pliocene, 177
Canidae. See Dog family
Capercaillie, 132
Carboniferous Period, 50
Carnivores —

Eocene, 118, 127

Oligocene, 146

Miocene, 156, 164

Pliocene, 172, 173, 183

Pleistocene, 194, 206, 210

{See also under various names.)
Carp, 168

Carpathian Mountains, 138, 168
Cat-dogs, 146, 156
Cat family —

Oligocene, 146

Miocene, 156

Pliocene, Earlier, 172, 173

— Later, 183

Pleistocene, 194, 206, 210

{See also under Machaerodonts, and
various names.)
Caucasian Group, 208, 209, 213
Cave-men, 199, 211
Cavy, 148
Cephalaspis, 36, 38
Cephalopods —

Cambrian, 18

Ordovician, 25

Silurian, 33

Devonian, 43

Carboniferous, 56

Permian, 66

Triassic, 73

Jurassic, 8$

Cretaceous, 107

Eocene, 137

{See also Ammonites, Ammonoids,
Belemnites, Goniatites, Nauti-
loids, Nautilus, Octopus.)

Ceratodus, 76

Ceratosaurus, 92

Ceraurus, 26

Cervidae. See Deer

Cetacea. See Dolphins, Whales,
Zeuglodonts

Cetiosaurus, 90

Chalicotheriidae, 140, 171

230 EVOLUTION

Chalk formations, iii
Chameleon, 135
Cheetahs, 173
Cheirolepis, 41
Cheiroptera. See Bats
Chelonians —

Permian, 64

Triassic, 79

Jurassic, 94

Cretaceous, 102

Eocene, 134

Miocene, 166

Pliocene, 180

Criptodira, 79, 94

Pleurodira, 79, 94, 134
Chevrotains —

Eocene, 129

Oligocene, 144

Pliocene, 179

Water, 179
Chimaera, 40, 87
Chimpanzee, 155, 179, 215
Chirocentrus, 106
Chitons, 24, 137
Chonetes, 32

Cirripedes. See Barnacles
Civets, 127, 147, 173
Cladophora, 17
Cladoselache, 39
Clams, 85, 137
Clematis, 154
Club-moss. See Lycopods
Coal, 51
Cobra, 167
Coccosteus, 39
Cockles, 73
Cockroaches, 52
Coelacanthidae, 58, 87, 105
Coelentera, 12

(See also Cladophora, Corals, Grap-
tolites, Jellyfish.)
Coleoptera. See Beetles
Compsognathus, 92
Condylarthra, 117, iig
Coney. See Hyrax
Conifers, 68, 70, 88, 112, 132, 153, 154
Corals —

Cambrian, 17

Ordovician, 21

Silurian, 28

Devonian, 47

Carboniferous, 53

IN THE PAST

Corals [cont.) —

Permian, 66

Triassic, 72

Jurassic, 82

Cretaceous, no

Eocene, 138

Oligocene, 140

Red, no

Reef-building, 28
Cordaites, 49, 50, 71
Cormorants, 112, 150
Coryphodonts, 122
Cowries, 85, 137
Crabs —

Jurassic, 86

Cretaceous, 106

Eocene, 137
Cranes, 131, 151
Craniidae, 23, 109
Crawfish, 106
Creodonts —

Eocene, 118, 127

Oligocene, 1 46

Miocene, 156

Pliocene, 173
Cretaceous Period, 98
Crickets, 89
Crinoids —

Cambrian, 17

Ordovician, 22

Silurian, 29

Devonian, 46

Carboniferous, 53

Permian, 66

Triassic, 72

Jurassic, 82

Cretaceous, no

Eocene, 138

Emancipation, 53, 82, no
Sanitary modifications, 30, 46, 53,66
Crocodiles —
Triassic, 77
Jurassic, 93
Cretaceous, 100
Eocene, 134
Miocene, 166
Pliocene, 179

— backbone, 93, 100

— breathing modification, 93, 100

— sea-roving, 94, loi
{See also Gavials.)

Cromagnon, 199

INDEX

231

Crossbills, 151
Crossopterygian Ganoids —

Devonian, 40

Carboniferous, 57

Permian, 65

Triassic, 75

Jurassic, 87

Cretaceous, 105
Crows, 151
Crustaceans —

Cambrian, 19

Ordovician, 25

Silurian, 34

Devonian, 42

Carboniferous, 56

Permian, 67

Triassic, 75

Jurassic, 86

Cretaceous, 106

Eocene, 137

{See also under various names.)
Cryptoclidus, 95
Cryptogams, 3

{See also under various plant-
names.)
Curlew, 166
Cushion-stars, 83
Cuttle-fishes, 137
Cyathaspis, 36

Cycad-conifers. See Cordaites
Cycad-ferns (Cycadofilices), 48, 50, 68,
71

Cycads, 68, 71, 88, 113
Cyclostomata, 39
Cynodictis, 128, 146
Cypress, 68, 70
Cystids —

Cambrian, 17

Ordovician, 22

Silurian, 29

Devonian, 47

Carboniferous, 53

Permian, 66

Dasdicurus, 185, 204
Dasyurus, 187
Date-shells, 55

Decapods. See Crabs, Lobsters,
Prawns, Shrimps

Deer family —
Oligocene, 145
Miocene, 157

Pliocene, Earlier, 171, 179

— Later, 183
Pleistocene, 194
Domesticated, 213
Irish, Great, 194
Mule, 158, 201
Muntjac, 157, 172, 183
Musk, 145, 179

Red, 183

Reindeer, 194, 199
Roe, 183
Sedgwick's, 183
Spotted, 172
Swamp, 179
Deiphon, 34

Denmark shell-mounds, 211
" Devils," Tasmanian, 207
Devonian Period, 38
Diadectes, 64
Dichograptus, 22
Dimetrodon, 63
Dinoceras, 123
Dinornis, 207
Dinosaurs —

Triassic, 77

Jurassic, 90

Cretaceous, 98

{See also under various generic
names.)

Reproduction, 92
Dinotheres, 161, 171, 174, 182
Diphycercal tail, 42
Diplodocus, 90, 98
Dipnoans, 41, 57, 65, 76, 105
Diprotodon, 187, 206
Divers, iii, 150
Dog-bears, 146, 156, 173, 174
Dog family —

Eocene, 128

Oligocene, 146

Miocene, 156

Pliocene, Earlier, 173

— Later, 183

Domesticated, 211, 212, 213
{See also Fox, Jackal, Wolf.)

Dog-fishes, 87

Dolichosaurs, loi

Dolichosoma, 59

Dolphins, 165

232

EVOLUTION IN THE PAST

Dorab, io6
Dormice, 124, 148
Dragon-flies, 52, 89
Drepanaspis, 38
Dryopithecus, 155
Ducks, 151
Dugongs, 130
Dunlins, 112, 132

Eagle, 132, 151
Eagle-rays, 105, 136
Earwigs, 89
Echinoderms, 13

(See also Blastoids, Brittle-stars,

Crinoids , Cystids, Holothurians,

Sea-urchins, Starfishes.)
Echinoids. See Sea-urchins
Echinosphaera, 22
Edaphosaurus, 63

Edentates, 118, 124,141,161,181,185,
203

(See also /armadillos, Ganodonts,
Sloths.)
Eels, 106
Egypt, 209, 214
Elands, 169, 178

Elasmobranchs. See Dog-fishes, Rays,

Sharks
Elasmosaurus, 103
Elasmotherium, 191
Elephants —

Eocene, 124

Miocene, 160

Pliocene, 171, 174, 182

Pleistocene, 189, 191, 193, 202

Present, 214

(See also Dinotheres, Mammoths,
Mastodon, Mceritherium, Palaeo-
mastodon, Stegodon, Tetrabelo-
don.) "

Elk, 189, 194

Elotherium, 143, 160

Embryology, 2

Engis, human remains, 199

Eocene Period, 116

Eoliths, 188

Eosiren, 130

Equidae. See Horses

Equisetales —

Cambrian, 20

Ordovician, 27

Devonian, 48

Carboniferous, 50

Permian, 67

Triassic, 70

Jurassic, 88

Cretaceous, 113
Equisetum, 70
Eucalyptus, 114
Europe, Glaciation, 190, 191

— Inter-glacial Epoch, 192

— Re-Glaciation, 196
Eurypterids. See Sea-scorpions
Evolution, doctrine of, i et seq.

Falcons, 132
Favosites, 29, 47, 53
Felidae. See Cat family
Ferns —

Silurian, 28

Devonian, 48

Carboniferous, 50

Permian, 68

Triassic, 70

Jurassic, 89

Adder's Tongue, 70

Bracken, 89

Eusporangiates, 70

Glossopteris, 68

Hart's Tongue, 89

Leptosporangiates, 70, 89

Male, 89

Marattiaceae, 50

Polypod, 70

Royal, 70, 89
Fig trees, 113
File-shells, 55, 85
Finches, 151
Fins, 40
Fishes, 2, 3 —

Silurian, 35

Devonian, 38

Carboniferous, 57

Permian, 64

Triassic, 75

Jurassic, 86

Cretaceous, 104

INDEX

Fishes (cont.) —

Eocene, 135

Miocene, 167

Ancestry, 14

Bony. See Teleosteans

Fins, 40

Flying, 106

Freshwater, 168

Spiny-finned, 106

Tails, 41, 58, 64, 76, 88

{See also Actinopterygian, Crossop-
terygian, Dipnoans, Ganoids,
Teleosteans. and various names.)
Fish-lizards. See Ichthyosaurs
Flamingoes, 112, 131, 150
Flowers, first known, 49
Flying Lizards. See Pterosaurs
Foraminifers —

Cambrian, 16

Permian, 66

Cretaceous, 110

Eocene, 138
Foxes, 156, 194
Frescoes, 200

Fringe-finned ganoids. See Crossop-

terygian
Frogs —

Eocene, 135

Oligocene, 140

Miocene, 167
Fungi, 8, 15, 20

Gad-flies, 152
GaU-flies, 152

Gannet-like birds, 131, 133
Gannets, 150
Ganodonts, 118, 141
Ganoids —

Devonian, 40

Carboniferous, 57

Permian, 64

Triassic, 75

Jurassic, 87

Cretaceous, 105

Eocene, 136

{See also Actinopterygian, Crossop'
terygian.)
Gastomis, 131

2.33

Gastropods, 14
Cambrian, 18
Ordovician, 24
Silurian, 32
Devonian, 44
Carboniferous, 52, 55
Permian, 66
Triassic, 73
Jurassic, 85
Cretaceous, 108
Eocene, 137
Oligocene, 140
Land, 52
Respiration, 73

( See also under various names.)
Gastrula, 12

Gavials, 77, 93, 166, 180
Gazelles, 129, 144, 169
Geese, 131
Geosaurus, 94
Gibbons, 155, 215
Gingko tree, 68, 70, 89
Giraffes —

Pliocene, 169, 177, 183

Present, 215
Giraffe-camel, 158
Glaciation —

Permian, 67

Pleistocene, 190 et seq.

America, N., 191, 192, 201

America, S., 202

Asia, 190

Europe, 190, 191, 196
Gluttons, 189, 194
Glyptocrinus, 22
Glyptodonts, 162, 185, 204
Gnats, 89
Goat, 169, 177
— domesticated, 212, 213
Goat-oxen, 178
Godwits, 132
Gomphoceras, 33
Goniatites —

Devonian, 44

Carboniferous, 56

Permian, 67
Gorillas, 155, 179
Graptolites —

Ordovician, 21

Silurian, 29
Grasses, 89, 114
Grasshoppers, 52

234

EVOLUTION IN THE PAST

Great Britain separated, 213
Grebes, 11 1, 150
Greenland, 154
Ground-sloths. See Sloths
Grouse, Sand, 151
— Willow, 200
Guillemots, 166
Gulls, 150, 166

Gymnosperms. See Cycads, Conifers,
and various names

Hadrosaurus, 100
Hag-fishes, 35
Halitherium, 150
Halysites, 29, 47
Hares, 148
Hartebeest, 178
Hatteria. See Sphenodon
Heart-urchins, 109
Hedgehogs, 148
Helicotoma, 24
Helladotherium, 170
Hemiaspis, 34
Hemipters, 27
Hermit-crabs, 137
Heron, 131, 166
Herring, 76, 105
Hesperornis, 112
Heterocercal tail, 42
Himalayas, 138
Hipparion, 170, 175, 182
Hippidium, 203

Hippopotamus, 177, 182, 189, 193
Hippurites, 108
Hoatzin, 3
Holoptychius, 41
Holothurians, 13, 17, 54
Homo. See Man

Homocercal tail, 41, 58, 64, 76, 88

Hoopoes, 151

Hoplopteryx, 106

Hornbills, 132

Hornets, 152

Horse-mackerel, 106

Horses —

Eocene, 120

Oligocene, 143

Miocene, 159

Pliocene, Earlier, 170, 175, 180

Horses (cont.) —

Pliocene, Later, 182, 185

Pleistocene, 189, 193, 203

Domesticated, 213

Keltic type, 182

South American, 203

Thoroughbred, 176
" Horsetails." See Equisetales
Hyaena, 173, 184
Hysenodon, 128, 146, 156, 173
Hydra, 12

Hydrozoa. See Cladophora, Grapto-
lites

Hymenocaris, 19
Hyopotamus, 144
Hyracodon, 142
Hyracotherium, 121
Hyrax, 129

Ibis, 131, 150
Ichthyomis, 112
Ichthyosaurs —

Triassic, 79

Jurassic, 95

Cretaceous, 102
Iguanodon, 98
Implements —

EoUthic, 188

PalaeoUthic, 195, 198, 199 209

Neolithic, 212, 213

Bronze, 214
India, Early Pliocene, 173
Inostransevia, 63, 77
Insectivores —

Jurassic, 97

Eocene, 118

Oligocene, 148

Miocene, 155

(See also Hedgehogs, Moles, Shrews.)
Insects —

Ordovician, 27

Devonian, 47

Carboniferous, 52

Triassic, 71

Jurassic, 89

Cretaceous, 114

OUgocene, 15^

(See also various names.)
Inter-glacial Epoch —

Europe, 192

INDEX

235

Inter-glacial Epoch {cont.) —

Hunters, 195
Iris, 154

Irish deer, the Great, 194
Isopods, 43

Jackals, 173
Jaguars, 173, 206
Jellyfish, 12, 17
Jungle-cats, 210
Jurassic Period, 82

Kangaroos, 186, 206
Kelts, 214
King-crabs —

Cambrian, 19

Ordovician, 26

Silurian, 34

Triassic, 75
Kingfisher, 132
Kites, 151
Kudus, 169, 178

Labyrinthodonts —

Carboniferous, 59

Permian, 61

Triassic, 76
LacertiUa. See Lizards
Lake-dweUings, 212
Lama, 158, 180, 203
Lamellibranchs. See Pelecypods
Lampreys, 39

Lampshells. See Brachiopods

Lanarkia, 36

Lancelets, 3

Lapworthura, 31

Lariosaurus, 78

Larks, 132

Lasanius, 36

Leaf-insects, 52

Lemurs —

Eocene, 119, 126

Ohgocene, 149

Miocene, 154

Leopards, Hunting, 173
Lepadocrinus, 29
Lepidaster, 31

Lepidodendron. See Lycopods

Lepidoptera. See Butterflies, Moths

Life, appearance of, 7

Limestone, Miolitic, 138

— Nummulitic, 138

Limpets, 18

Lions, 184, 194

pouched, 187, 207
Listriodon, 159
Litopterns —

Miocene, 163

Pliocene, 186

Pleistocene, 205
Liverworts, 15, 20
Lizards —

Jurassic, 93

Eocene, 135

Miocene, 167

Flying. See Pterosaurs
Llama. See Lama
Loach, 168
Lobsters, 86, 106
Locusts, 52

Lophiodonts, 120, 140, 157
Loxomma, 59
Lung-fishes. See Dipnoans
Lycopods —

Cambrian, 20

Ordovician, 27

Silurian, 28

Devonian, 48

Carboniferous, 50

Permian, 67

Triassic, 7c

Jurassic, 88
Ljmx, 184

Macaques. See Apes
Machserodonts —

Oligocene, 147

Miocene, 156

Pliocene, Earlier, 172, 173

— Later, 183

Pleistocene, 206
Macrauchenia, 205
Magnolia, 113

236

EVOLUTION IN THE PAST

Maidenhair tree. See Gingko
Mammals, appearance of, 80

— decline of, 214

— origin of, 80

— placental, 117

(See also under various names.)
Mammoths, 191, 193, 197, 200, 201,

202, 210
Man —

America, 202, 209

Aryan, 213

Aurignacensis, 198

Caucasian, 208, 209, 213

Cave, 199, 211

Cradle-land, 208, 209

Cromagnon, 199

Descent, 127, 187

Dispersal, 208

Engis, 199

Eolithic, 188

Galley Hill, 198

Heidelbergensis, 190

Inter-glacial, 195, 196

Kelts, 214

Lake-dwellers, 212

Mentone, 199

Mollusc-eaters, 211

Mongolian, 209

Mousteriensis, 196

Neanderthal, 195

Negroid, 208, 209

Neolithic, 212, 213

PalaeoUthic, 195, 198, 199, 209

Pithecanthropus, 187

Pliocene, 188

Semitic, 213

Spy, 198
Manatees, 130, 150
Marsupials —

Triassic, 80

Jurassic, 97

Cretaceous, 114

Eocene, 119

Oligocene, 140

Miocene, 164

Pliocene, 186

Pleistocene, 206

(See also under various names.)
Martens, 156
Mastigocrinus, 30
Mastodons —

Pliocene, 174, 180, 182

Mastodons (cont.) —

Pleistocene, 202
Mayflies —

Devonian, 47

Carboniferous, 52

Jurassic, 89
Medusas. See Jellyfish
Megalohyrax, 129
Megalosaurus, 92, 99
Megatherium, 185, 204
Melaniidse, 33
Menes, King, 214

Merostomata. See Sea-scorpions,

King-crabs
Mesohippus, 143
Mesonyx, 128
Mesopithecus, 172
Metamynodon, 142
Metriorhynchus, 94, loi
Microlestes, 80
Millepedes, 47, 52
Miocene Period, 154
Miolitic hmestone, 138
Mitre-shells, 137
Moa, 207

Moeritherium, 124
Moles, 97, 148

MoUuscoida. See Brachiopods, 'Poly-

zoans
Molluscs, 14

(See also Cephalopods, Chitons,

Gastropods, Pelecypods, Ptero-

pods, Scaphopods, and various

names.)
i Mongolian races, 208, 209
Monkeys. See Apes
Monotremes, 3, 80
Morality, progress of, 81
Morula stage, 10
Mosasaurs, loi
Mosquitoes, 89
Moths, 114, 152
Muntjacs. See Deer
Musk-oxen, 189, 194
Mussels, 18, 32, 44, 55, 73, 137
— River, 44

Mustelidae. See Badger, Marten

Glutton, Polecat, Weasel
Mutations, 4
Mylodon, 185, 204
Myriapods, 47, 52

INDEX

237

Natural Selection, 5
Nautiloids —

Cambrian, 18

Ordovician, 25

Silurian, 33

Devonian, 43

Carboniferous, 56

Permian, 66

Triassic, 74

Jurassic, 86
Nautilus —

Carboniferous, 56

Permian, 66

Triassic, 74

Jurassic, 86

Cretaceous, 108

Eocene, 137
Neander human remains, 195
Nebalia, 5, 19
Nebular Hypothesis, 7
Necrolemur, 149
Negroids, 208, 209
Neolithic. See Implements
Nesodon, 163
Newts, 58
Nilgai, 178

Nummulites, 138, 140
Nuthatches, 132

Oaks, 113

Oceans, formation of, 7
Ocelots, 206
Octopus, 108
Odontopteryx, 131
Okapi, 170
Olenellus, 19
Oligocene Period, 140
Olive-shells, 137
Onchus, 36

Ophidia. See Snakes, Cobra, Python,

Rattle-snake
Ophiuroids. See Brittle-stars
Opossum, 97, 119, 140, 165, 185
Opossum-rat, 165
Orang, 179, 215
Ordovician Period, 21
Oreopithecus, 155

Orohippus, 121
Orthoceras annulatum, 33
Osprey, 132
Ostracoderms, 35, 38
Ostracods —

Cambrian, 19

Ordovician, 26

Silurian, 35

Devonian, 43
Ostriches, 179
Otters, 147, 156
Oudenodon, 63
Ovibos. See Musk-oxen
Owls, 132, 151
Oxen, 178, 183
— domesticated, 212, 213
Oysters —

Devonian, 44

Carboniferous, 55

Triassic, 73

Jurassic, 84

Cretaceous, 108

Edible, 55, 85

Pearl, 32, 55, 66, 85

Saddle, 44

Thorny, 73, 84

Palaeohatteria, 62
Palaeolithic. See Implements
Palaeomastodon, 125
Palaeostraca. See King-crabs Sea-
scorpions, Trilobites
Palseotheres, 122, 140, 157
Palms, 114

Panama, Isthmus of, 181
Paradoxides, 19
Pareiasaurus, 62, 77
Parrots, 151
Partridges, 132, 151
Patriofelis, 128
Pearl-oysters. See Oysters
Peccaries, 143, 159, 180
Pelecypods —

Cambrian, 18

Ordovician, 24

Silurian, 32

Devonian, 44

Carboniferous, 55

Permian, 66

Triassic, 72

Jurassic, 84 •

238 EVOLUTION

Pelecypods {cont.) —
Cretaceous, io8
Eocene, 137
Miocene, 168

(See also under various names.)
Pelicans, 150
Pelycosaurians, 63, 77
Penguins, 132
Pentamenis, 32
Perch, freshwater, 168

— sea, 106
Periechocrinus, 29
Periwinkles, 18
Permian Period, 61
Phacops, 34
Phalangers, 187, 207
Phanerogams, 3

(See also under various plant-
names.)
Pheasants, 151
Phenacodus, 2, 120, 140
Phyllopods, 19
Pigeons, 151
Pigs. See Swine
Pike, 168

— bony, 88
Pineapple plants, 154
Pinks, 154
Pithecanthropus, 187
Placentals, 117
Plantain-eaters, 166
Plants. See Vegetation
Platystrophia, 23
Pleistocene Period, 189
Plesiosaurians —

Triassic, 78

Jurassic, 94

Cretaceous, 103

Ancestry, 78
Pleuracanthus, 57, 76
Pliocene Period —

Earlier Epoch, 169

Later Epoch, 182
Pliopithecus, 155
Pliosaurus, 95
Plovers, 151, 166
Plum trees, 154
Pod-shrimps, 19, 26, 42, 56
Poebrotherium, 145
Polacanthus, 98
Polecats, 156
Polypterus, 105

IN THE PAST

Polyzoans —

Ordovician, 25

Silurian, 32

Devonian, 44

Carboniferous, 55

Permian, 66

Triassic, 72

Jurassic, 84

Cretaceous, 109

Eocene, 138
Poplars, 1 1 3
Poppies, 154
Porcupines, 148, 155
Porifera. See Sponges
Portheus, 105
Pottery, 212, 213
Prawns, 75, 86, 106
Praying insects, 152
Present Period, 211
Primates —

Eocene, 119, 126

Oligocene, 149

Miocene, 154, 164

Pliocene, 172, 179, 184, 187

{See also Apes, Lemurs.)
Procamelus, 158
Procyonidae. See Raccoons
Productus, 54, 66
Propliopithecus, 127
Proterotherium, 163, 186
Protoceras, 144
Protohippus, 159
Protospongia, 16, 21
Protozoans — 8

Cambrian, 16

Cretaceous, no

Eocene, 138

(See also Foraminifers, Nummulites,
Radiolarians.)
Ptarmigan, 200
Pteranodon, 104
Pterichthys, 38
Pteropods, 18, 24
Pterosaurs, 95, 104
— wings of, 95
Puma, 206
Pycnodonts, 136
Pyrenees, 138
Pyrotherium, 164, 186
Python, 135

INDEX

Quagga, 215
Quail, 132

Rabbits, 148 ^
Raccoons, 157
Radiolarians, 16, 110
Rails, 112, 131
Rats, 148
Rattle-snakes, 167

Ray-finned ganoids. See Actinop-

terygian
Rays, 57, 87

— Eagle, 105, 136

— Electric, 136
Razor-sheUs, 44
Redshanks, 151
Reindeer, 194, 199'
Reptiles, 61

{See also under various names :
Crocodiles, Dinosaurs, etc.)
Rhinoceroses —
Eocene, 121
Oligocene, 142
Miocene, 157

Pliocene, Earlier, 171, 176, 180
— Later, 182
Pleistocene, 191, 193
Present, 214

Woolly, 191, 197, 200, 210
{See also Hyracodon, Metamynodon,
Elasmotherium.)
Rodents, 97
Eocene, 123
Oligocene, 148
Miocene, 155
Horned, 156, 180

{See also Beavers, Hares, Squirrels,
etc.)
Ruminants —
Eocene, 128
Oligocene, 144
Miocene, 157

{See also Camels, Deer, Oxen, etc.)
S

" Sabre-tooths." See Machaerodonts
Salamanders, 58, 167

Salmon-shaped fishes, 88

Samotherium, 170

Sandgrouse, 151

Sandhoppers. See Amphipods

Sarcophiles, 207

Sassafras, 113

Saw-fishes, 104

Saw-flies, 152

Scallops, 32, 55

Scaphopods, 24, 33

Scehdosaurus, 91

Scelidotherium, 185

Scorpions, 35, 52

Sea-anemones, 12

Sea-bream, 106

Sea-cows. See Sirenians

Sea-cucumbers. See Holothurians

Sea-fans, 21, no

Sea-firs, 17

Sea-lilies. See Crinoids
Seals, 166
Sea-perch, 106

Sea-scorpions (Eurypterids) —

Cambrian, 19

Ordovician, 26

Silurian, 34

Devonian, 42

Carboniferous, 56

Permian, 67
Sea-urchins —

Ordovician, 23

Silurian, 31

Devonian, 45

Carboniferous, 54

Permian, 66

Triassic, 72

Jurassic, 83

Cretaceous, 109

Eocene, 138
Seaweeds, 15, 21
Seeds, 48

Selachii. See Sharks, Rays
Semnopithecus, 172
Sequoia firs, 68, 70, 112
Serpulites, 31
Sertularians, 17
Sewing, 200
Sharks —

Silurian, 36

Devonian, 39

Carboniferous, 57

Permian, 65

240

EVOLUTION

IN THE PAST

Sharks (cont.) —
Triassic, 75
Jurassic, 87
Cretaceous, 104
Eocene, 135
Miocene, 167
Angel, 87
Blue, 135
Comb-toothed, 87
Cow, 39

Hammer-headed, 167

Porbeagle, 104

Port Jackson, 36, 57, 87

Thresher, 167
Shearwaters, 150
Sheep, 158, 189
Shell-mounds, Danish, 211
Ship-worms, 85
Shrews, 118, 149
Shrikes, 151
Shrimps —

Cambrian, 19

Ordovician, 26

Devonian, 42

Carboniferous, 56

Triassic, 75

Jurassic, 86

Cretaceous, 106
Siberia, igo, 194, 197
Sigillaria, 50, 67, 70, 89
Silures, 213
Silurian Period, 28
Sirenians, 130, 150
Sivatherium, 177
Siwalik formation, 173
Skates. See Rays
Sloths, Ground —

Miocene, 161

Pliocene, 185

Pleistocene, 204

Ancestry, 162
Snails. See Gastropods, Pteropods
— Land, 44, 52
Snake-flies, 52
Snakes, 135, 167
Sparassodonts, 164
Speech, 190, 198
Sphserexochus, 34
Sphenodon, 62

Sphenophyllum, 27, 47, 50, 70
Spiders, 52, 152
Spinning, 212

Spirifer, 32, 45, 55, 66, 84
Spitzbergen, 89, 154
Sponges —

Cambrian, 16

Ordovician, 21

Silurian, 28

Devonian, 47

Carboniferous, 52

Permian, 66

Triassic, 71

Jurassic, 82

Cretaceous, 110

Calcareous, 47, 71
Spores, 7, 48
Sprats, 88
Spring-tails, 52
Spruces, 68, 70, 189
Spy human remains, 198
Squalodon, 150, 165
Squids, 86
Squirrels, 124, 148
Starfishes —

Cambrian, 17

Ordovician, 23

Silurian, 30

Devonian, 46

Carboniferous, 54

Permian, 66

Jurassic, 83
Starlings, 132
Staurocephalus, 34
Stegocephs, 58, 61, 76
— ancestry, 59
Stegodons, 175
Stegosaurus, 91, 98
Stick-insects, 52
Stilts, 151

Storks, 112, 131, 166
Streptelasma, 21
Sturgeon, 88, 105, 136
Sun-stars, 83
Survival of the Fittest, 5
Swifts, 132
Swine —

Eocene, 125

Oligocene, 143

Miocene, 159

PUocene, Earlier, 172, 176

— Later, 183
Syndyoceras, 157
Synxiphosura. See King-crabs
Systemodon, 121

INDEX

241

Tapirs, 121, 170
Tarpon family, 106
Tasmania, aborigines of, 208
Teleosaurs, 93
Teleosteans, 88, 105, 136
Tellens, 85
Tench, 168
Terataspis, 42
Termites, 89
Terrapins, 166

Tetrabelodon, 160, 171, 174, 180,

182

Thelodus, 36, 38,
Theridonts, 63, 80
Theromorphs, 62
Thrips, 152
Thrushes, 151
Thylacine, 207
Thylacoleo, 187, 207
Tigers, 173

— Sabre-toothed. See Machaero-

donts
Tillodonts, 123
Tinoceras. See Dinoceras
Titanotheres, 121, 141
Toads, 140
Tortoises —

Permian, 64

Triassic, 79

Jurassic, 94

Cretaceous, 102

Eocene, 134

Miocene, 166

Phocene, Earlier, 180
Toxodonts, 162, 185, 204
Tremataspis, 36
Triassic Period, 70
Triceratops, 99, 116
Trilobites, 14

Cambrian, 19

Ordovician, 25

Silurian, 34

Devonian, 42

Carboniferous, 56

Permian, 67
Trinucleus, 26
Trogons, 151

Tuatera. See Sphenodon
Turkeys, 151 166
Turtles, 94, 102, 135, 166

Turtles (cont.) —

Edible, 102

Leathery, 135

Loggerhead, 102

Tortoiseshell, 166
Typotheres, 163, 186, 205

Uintatherium. See Dinoceras
Univalves. See Gastropods
Ursidae. See Bears

Variations, 4
Vegetation, 8, 15

Cambrian, 20

Ordovician, 21, 27

Silurian, 28

Devonian, 47

Carboniferous, 50

Permian, 67

Triassic, 70

Jurassic, 88

Cretaceous, 112

Eocene, 132

Oligocene, 152

Miocene, 154

{See also various names.)
Venus-shells, 85
Viverridae. See Civets
Volvox, 3

Vultures, Secretary, 151
W

Walchia, 68
Warblers, 132
Wart-hog, 176
Wasps, 152
Waterbuck, 178
Weasels, 147
Whales —

Eocene, 130

Oligocene, 149

Miocene, 165

Bottle-nose, 165

Hump-back, 165

242

EVOLUTION IN THE PAST

Whales {cont.) —
Sperm, 165
Whalebone, 165
White, 165

Zeuglodont, 131, 149, 165
Whelks, 85, 137
Wild boar, 183
Willows, 113
Wingshells, 24, 32, 55
Wolverines, 189, 194
Wolves, 127, 146, 156, 173, 183, 189
— pouched, 207
Wombats, 186, 206
Woodpeckers, 132, 151
Worms, 13, 18, 23, 31

Xiphodonts, 129, 144

Yellow races. See Mongolian
Yews, 68, 70

Zafrentis, 28
Zamia, 71

Zebra, 182, 189, 193, 215
Zeuglodonts, 131, 149, 165

WILLIAM BRENDON AND SON, LTD.
PRINTERS, PLYMOUTH

3 5002 00100 8403

Knipe, Henry Robert.
Evolution in the past.

711

79280

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