The haunts of life

LIBRARY

THE HAUNTS OF LIFE

SOME OTHER WORKS
BY THE SAME AUTHOR

Fourth Edition.

THE WONDER OF LIFE. MELROSE, 1914. Pp.
658. 100 Illustrations.

Fifth Edition.

THE BIOLOGY OF THE SEASONS. MELROSE,
1911. Pp.379. 12 Coloured Plates.

Fifth Edition.

DARWINISM AND HUMAN LIFE. MELROSE.
Pp. 263. 12 Plates.

Third Edition.

SECRETS OF ANIMAL LIFE. MELROSE, 1920.
Pp. 324. 24 Figs.

NATURAL HISTORY STUDIES (Selections from the
Author's own Works). MELROSE. Pp. 254.
30 Figs.

THE CONTROL OF LIFE. MELROSE, 1921.
Third (Revised) Edition.

HEREDITY. MURRAY, 1918. Pp. 627. 47 Figs.
Fourth (Revised] Edition.

THE STUDY OF ANIMAL LIFE. MURRAY, 1917.
Pp. 477. 124 Figs.

INTRODUCTION TO SCIENpE. WILLIAMS &
NORGATE (Home University Library), 1912.
Pp. 256.

Seventh Edition.

OUTLINES OF ZOOLOGY. HENRY FROWDE AND
HODDER & STOUGHTON, 1921. Pp. 855.
420 Figs.

THE SYSTEM OF ANIMATE NATURE. WILLIAMS
& NORGATE, 1920. 2 vols. Pp. 687.

SALMON ASCENDING A FALL.

Frontispiece']

THE
HAUNTS OF LIFE

BEING SIX LECTURES DELIVERED
AT THE ROYAL INSTITUTION
CHRISTMAS HOLIDAYS, 1920-1921

BY

PROF. J. ARTHUR THOMSON, M.A., LL.D.

ANDREW MELROSE LTD.

LONDON 6- NEW YORK

1921

THIS LITTLE BOOK
IS DEDICATED GRATEFULLY
TO A VETERAN NATURALIST

EMERITUS PROFESSOR W. C. M'INTOSH

M.D., LL.D., F.R.S.

WHO HAS DEVOTED HIS LIFE
TO THE STUDY OF ANIMALS IN THEIR HAUNTS

PUBLISHERS' NOTE

the illustrations in this book twelve
plates are by Mr. William Smith ; the
remainder are by Miss Alice M. Davidson.

PREFACE

THIS simple book consists of six lectures
which I had the honour and pleasure of
giving at the Royal Institution in the Christmas
holidays, 1920-1921. The aim of these lectures
was mainly to help my very alert audience to
form vivid pictures of the great haunts of
animal life, and to get glimpses of the subtle
ways in which living creatures solve the
problems of particular places. I have kept in
the printed pages as closely as I could to what
I said at the time, hoping to secure the virtue
of simplicity. I think it would be very un-
gracious if I did not use the opportunity of this
preface to thank Sir James Dewar, LL.D.,
D.Sc., F.R.S., for the great kindness that he
showed me when I was for a delightful
fortnight in the service of the Royal Institution.

J. A. T.

vi

CONTENTS

CHAPTER I
THE SCHOOL OF^THE SHORE

PAGE

The Shore of the Sea— In Deeper Waters near Shore— A
Representative Population — A Difficult Place to Live
in— The Struggle of the Shore— The Circulation of
Matter — Cannibalism in the Cradle — Shore Sea-
weeds— Food-getting on the Shore — The Story of the
Angler— The Star-fish and Sea-urchin Fight— Shifts
for a Living on the Shore — Masking — A Limb for a
Life — Colour Camouflage — Love on the Shore — The
Story of Palolo— A Great School . . .-.:.; v; t

^CHAPTER II

THE OPEN SEA

Contrast between Shore and Open Sea — The Floating
Sea-Meadows — The Animals of the Open Sea — Sea-
deserts — Swimmers and Drifters — The Whale as a
Great Bundle of Fitnesses— The Story of the Storm
Petrel— Open-Sea Insects— Turtles— Sea-Snakes and
Sea-Serpents—Fitnesses of Open-Sea Drifters— The
Story of the Floating Barnacle — Hunger and Love in
the Open Sea— The Open Sea as a Nursery . . 64

ix

x CONTENTS

CHAPTER III

THE GREAT DEEPS

PAGE

The Challenger Expedition— The Deep Deep Sea —
Great Pressure— Very Cold— Very Dark— Very Calm
and Silent — Monotony — No Depth Limit to Life — No
Plants in the Deep Sea — No Rottenness — A Repre-
sentative Fauna — Fitnesses of Deep-Sea Animals —
Puzzle of Phosphorescence— Big Eyes and Little
Eyes — Origin of Deep-Sea Animals — Hunger and
Love in the Deep Sea — Retrospect . . . 104

CHAPTER IV

THE FRESH WATERS

Variety of the Fresh Waters — Similar Animals in Widely
Separated Places— From Salt Water to Fresh-
Origin of Fresh-Water Animals— Circulation of Matter
in the Fresh Waters— The Web of Life in the Fresh
Waters— The Danger of Drought— The Danger of
Frost — The Danger of Flood — Parental Care among
Fresh-Water Animals— The Story of the Eel— The
Story of the Salmon— The Story of the Lamprey-
Water Insects— The Story of the Fresh- Water Spider 136

CHAPTER V
THE CONQUEST OF THE DRY LAND

Tell-tale Evidences of Marine Ancestry— Origin of Land
Plants— The Three Great Invasions of the Dry
Land— New Ways of Breathing— Changes in Move-

CONTENTS xi

PAGE

ments— New Ways of Looking after the Young— New
Kinds of Protection — Betwixt-and-Between Animals
— Haunts within Haunts — Beneath the Ground — Cave
Animals — Arboreal Life . . . .185

CHAPTER VI

THE MASTERY OF THE AIR

What Getting into the Air meant— The Flight of Insects
— Why are there so many Insects? — The Flying
Dragons— The Flight of Birds— Different Kinds of
Flying in Birds — Migration the Climax — The Fourth
Solution of Flight — Fitnesses of Birds and Bats —
Attempts at Flight — Gossamer Spiders . .231

Index . . . , . » . 270

LIST OF ILLUSTRATIONS

FIG. *AGE

1. KING-CRAB. . . « . Y . . . 14

2. ACORN-SHELLS OR ROCK-BARNACLES . *'"' . 40

3. SKATE-SUCKER . . • , . ; .... 57

4. RIGHT WHALE . . * . • . •'•'» '* '•' » . 78

5. SEA-SKIMMER . %i~ . "' . . r . . 86

6. JELLY-FISH . . . . . . . . . 91

7. LIFE-HISTORY OF THE ANGLER . . . . 93

8. OPEN-SEA WATER-FLEA . . „ - . . . 95

9. CLUSTER OF BARNACLES . . '.V . . 97

10. FLOATING BARNACLES .*..'. . . 98

11. FEATHER-STARS OR SEA-LILIES . . . .121

12. SEA-PENS AND UMBELLULAS 127

13. CIRCULATION OF MATTER * . . . .146

14. LIFE-HISTORY OF GNAT 152

15. QUEENSLAND MUD-FISH . . . . . .155

16. SPOTTED SALAMANDER .... . » .160

17. GARDEN SPIDER , ' . . . . -. . 180

1 8. FEMALE FRESH- WATER SPIDER 182

xiv LIST OF ILLUSTRATIONS

FIG. PAGE

19. PERIPATUS , 194

20. CENTIPEDE . „ . * , . . . . 195

21. GREEN LIZARD . * . » . • . .201

22. JERBOA . » : f *. ,* . . . . 206

23. AUSTRALIAN COLLARED LIZARD . ' , . . 208

24. AUSTRALIAN DUCKMOLE . ... , v,A :M>,., , . 211

25. SPINY ANT-EATER .ljfv . . 218

26. PERIOPHTHALMUS • . « ^ • ^ t •> .-.*•• • • 222

27. ROBBER-CRAB . . . . ^ « » . . 224

28. DIAGRAM OF SOME BURROWERS . . » . 227

29. WINGS /. , . » . 252

30. FLYING FISHES 259

31. FLYING TREE-TOAD 261

32. LITTLE FLYING DRAGON OF MALAY . , . 262

33. GOSSAMER SPIDERS . . . . « . . 268

LIST OF PLATES

SALMON ASCENDING A FALL . . Frontispiece

PLATE FACING PAGE

I. CROWDED GROUP OF GUILLEMOTS ON A STACK

OF ROCK

II. TERNS OR SEA-SWALLOWS FLYING ON THE

SHORE . 1 1

III. FOUR OPEN-SEA ANIMALS . . . . . 64

IV. GLAUCOUS GULL AT LERWICK ... . 67
V. OPEN-SEA ANIMALS . . . . . ; . 73

VI. THE STORM PETREL IN THE OPEN SEA . . 84

VII. THE FLOOR OF THE DEEP SEA . . . . 105

VIII. DEEP SEA NEAR SHORE 115

IX. A FRESH- WATER POOL . . . . .140

X. A FRESH-WATER POOL . . . . .158

XI. SNOW-COVERED MOORLAND IN WINTER . . 220

XII. A CAVE IN DALMATIA . * . ».- - * .228

XIII. DIAGRAM OF FIVE HAUNTS OF LIFE . . . 231

XIV. BATS FLYING IN THE TWILIGHT . . ;. . 254

XV. FLYING DRAGONS, DRACO VOLANS, OF THE

FAR EAST . •.'.>.»* > ,V • 260
XVI. GULLS IN FLIGHT 266

THE HAUNTS OF LIFE

CHAPTER I
THE SCHOOL OF THE SHORE

The Shore of the Sea — In Deeper Waters near Shore — A
Representative Population — A Difficult Place to Live in —
The Struggle of the Shore— The Circulation of Matter-
Cannibalism in the Cradle — Shore Seaweeds — Food-
getting on the Shore — The Story of the Angler — The
Star-fish and Sea-urchin Fight — Shifts for a Living on
the Shore — Masking — A Limb for a Life — Colour Camou-
flage— Love on the Shore — The Story of Palolo — A Great
School.

IT is interesting to watch a big river rising
slowly in flood. The water overtops the
banks and spreads foot by foot everywhere,
filling every hollow, forgetting no corner. So
is it with living creatures ; they spread over all
the earth. Life is like a river that is always
overflowing its banks. There are no fishes in
the Great Salt Lake of Utah, there are no
birds swimming on its surface, yet there are
brine-shrimps and two or three more living

2 THE HAUNTS OF LIFE

creatures tenanting its dense waters. Little
fresh-water snails may be seen creeping on the
stones close to the brink of the Niagara Falls.
An army of a million tiny wingless insects
has been observed crossing the Mer de Glace
near Chamonix. There are insects that run
about on the surface of the Open Sea. There
are many animals that find a home in coal-pits.
It seems as if there are no corners which living
creatures have not explored, from the great
abysses of the Deep Sea, perhaps six miles
below the surface, to near the summits of the
Alps, from the floating iceberg in the North
to beneath ten feet of ice on the Antarctic
shore. Perhaps there are always some living
creatures trying to conquer a new kingdom.
Life is a kind of activity, and living creatures
tend to be restless, seeking out places where
they can express themselves and assert them-
selves more fully.

Thus it has come to pass that living creatures
have spread over all the earth, and in the
waters under the earth, and in more than the
seven seas. One may almost say that over
earth and sea life is omnipresent. But it is
very useful to distinguish Six GREAT HAUNTS
OF LIFE :

THE SCHOOL OF THE SHORE 3

I. THE SHORE OF THE SEA (Littoral).
II. THE OPEN SEA (Pelagic).

III. THE DEPTHS OF THE SEA (Abyssal).

IV. THE FRESH WATERS (Fluviatile, Lacus-

trine, etc.).

V. THE DRY LAND (Terrestrial).
VI. THE Am (Aerial).

THE SHORE OF THE SEA

By the shore-haunt or littoral region natural-
ists mean more than is suggested in ordinary
conversation when we speak of the seashore.
For then we mean the stretch between tide-
marks, whereas the naturalist's shore-haunt
is the whole of the comparatively shallow,
well-lighted, seaweed-growing area round the
margin of a continent, or of an island that
was once part of a continent. There are
places where there is practically no shore ; for
instance round an oceanic island that has been
formed by corals growing on the shoulders
of a submarine volcano. In such a place a
stone thrown out from the land will drop —
kerblunkity blink — into really deep water.
And there are other places where the shore
goes out and out for many miles ; for instance,

4 THE HAUNTS OF LIFE

where a fringing coral-reef extends far out to
sea. The naturalist's shore-haunt is the whole
of the seaweed-growing area, and we call it
shore, although the water may be deep enough
to float a navy.

The shore-haunt is not very large compared
with other haunts. It occupies about nine
million square miles, but that is only between
six and seven per cent, of the sea - covered
surface of the globe. It is a very long area,
going in and out, by bay and creek, by firth
and fiord, for about 150,000 miles. And it is
a region of great diversity, differing from place
to place according to the geological character
of the shore, according to the mineral materials
that the streams bring down from the land,
and according to the jetsam that is thrown
up from the sea. In some places the whole
of the shore between tide - marks is covered
with a thick mass of dead seaweed, which rots
away and smells badly when the tide is out.
There are crowds of tiny creatures — e.g. allies
of sand-hoppers — working away among this
decaying seaweed ; but the ordinary life of the
shore-pools has been smothered, and explora-
tion in 'this kind of shore -haunt is rather an
acquired taste. There are shores and shores.

THE SCHOOL OF THE SHORE 5

Even if we keep to the shore in the narrower
sense there is great variety of conditions.
Take first the great masses of rock which often
run far out to sea. Their tops and their sea-
ward faces are exposed for the greater part of
the day to the full violence of the wind and
the heat of the sun ; as the water rises the
waves beat against them, and they are only
completely submerged for a short time at very
high tide. Yet even these have their inhabit-
ants. Behind and between these weather-
beaten masses there is shade and moisture ;
sheltered nooks and crannies abound ; the
smaller rocks at their bases are covered with
sea-wrack, and every hollow contains a quiet
pool of water left by the receding tide, each
pool harbouring a crowded life.

Beside the rocks are the great stretches of
flat, smooth sand where we have built castles
and dug moats, and the sands, too, have their
own particular population, though it is not
always easy to see it. Sometimes instead of
sand there is shingle, gravel, or even large
pebbles smoothed or rounded by the action
of the waves. This kind of shore is the most
unfavourable of all to animal life. We shall
easily find the reason for ourselves if we bathe

6 THE HAUNTS OF LIFE

or wade among the surf on a pebbly shore,
for on a rough day we may come out of the
water tingling and bruised all over with the
continually moving stones.

The mud flats formed at river-mouths by
the soil carried down by the streams have their
inhabitants too, as we can easily guess from the
large numbers of birds that are busy feeding
there at low tide.

Finally, there is the most populous part of
the whole region, the stretch of flat rocks
covered with the great seaweeds — from which
the belt takes its name — " the laminarian zone."
A part of this region is not uncovered except
at very low tides.

IN DEEPER WATER NEAR SHORE

In warm seas, beside a coral-reef for in-
stance, naturalists have been able to work for
hours at a depth of 10 to 15 feet. They simply
put on a metal hood fitting the shoulders and
connected with a compression-pump on the
launch above by means of a long hose-pipe
which allows complete freedom of movement.
The diver breathes freely inside his hood, and
the weight of it is greatly reduced in the water.

PLATE I.— CROWDED GROUP OF GUILLEMOTS, ON A STACK OF ROCK, FARNE ISLANDS.

Note also some Kittiwakes.

Photograph by NORRIE, Fraserburgh.

THE SCHOOL OF THE SHORE 7

It is possible in this way to get very near the
animals, and to watch their goings on.

Mr. W. H. Longley tells of his experiences
beside a tropical coral-reef. "It is a strange
world in which the diver finds himself ; it is so
small and still ; so surrounded with mystery ;
so surprisingly unlike that which one imagines
it to be, observing it from the surface. Even
when the light is brightest, and the water most
free from sediment, one never sees objects at
a greater distance than a few yards (in one
very favourable case, fifteen paces) ; and if a
heavy surf is pounding a short distance sea-
ward, so much debris may be borne inshore on
a rising tide that one may be shut in almost as
completely as in a blinding snowstorm, and
have no means of finding one's way back to
the boat other than following the hose. No
sound reaches one save that of the air rushing
into the hood at each stroke of the pump
above. Graceful Gorgonians (i.e. Sea-fans ;
much branched, flexible, Alcyonarian corals),
purple, brown, yellow, or olive, may sway
gently as the lazy swell rolls overhead ; or, as
one clambers about the face of some submerged
escarpment, one may see, from below, sheets
of foam spreading where trampling rollers

8 THE HAUNTS OF LIFE

raised by an incessant trade wind have broken.
Yet all transpires in perfect silence." One
feature that contributes to the strangeness of
the surroundings is that all vertical distances
prove to be much greater than they appear
from the surface of the water. An apparently
smooth floor turns out to be rough, and a rough
one is found to be seamed by ragged crevasses.
Mr. Longley tells us of some of the sights
he saw. A bit of food thrown on to the sandy
floor would tempt crabs out of hiding ; they
would scuttle over the bottom like shadowy
ghosts, so like are they to their surroundings ;
then they would scrape and scratch a little
with their hind legs and go down backwards
out of sight. Flounders, coloured and patterned
just like the bottom, would rise and sink again,
burying themselves in the drifting sand, all but
their protruding watchful eyes. From a tiny
hole in the coral a small fish " with an enormous
dorsal fin would protrude half its body, and
rapidly and repeatedly elevate and depress its
great banner, while another seems to respond
to the signal." " Often one observes incidents
which remain incomprehensible, as when two
yellow grunts (Hcemulon sciurus) approach one
another slowly, snout to snout, open their

THE SCHOOL OF THE SHORE 9

mouths to the limit of their gape, and gaze, as
it seems, for several seconds, as if in rapt
attention, each at the patch of bright red on
the other's mouth."

A near view shows that there is haunt
within haunt. There are sandy corners and
seaweedy corners, sheltered coral basins and
open reefs, shady places and illumined places,
and all the different levels from the floor to
the surface. Of course there are bold wanderers
that go everywhere, but on the whole each
creature has its favourite and habitual corner,
to which it is particularly well suited, especially
as regards its colour and patterns. And different
creatures tenant the same place at different
times : thus, when evening approaches, the
day-feeding fishes disappear, and out of the
recesses of the reef come night-feeding fishes,
first Jn twos and threes, and then in schools.
There are many " Box and Cox " arrangements
in Nature.

The big result of close observation of the
shore-haunt is to show that it includes a great
variety of surroundings, and that many a
creature has a particular niche where it is
most at home.

io THE HAUNTS OF LIFE

A REPRESENTATIVE POPULATION

Of all the haunts of life, the shore has the
most representative fauna or assemblage of
animals. Almost every kind of creature is
there. Let us begin at the top of the genea-
logical tree.

On some quiet British shores the seals come
out of the water to rest, and are sometimes
caught napping by men who have no mercy.
They bring forth their young ones, usually
one for each mother, in caves or in sheltered
nooks among the rocks ; and this tells us part
of the secret of seals, — that they are the aquatic
descendants of terrestrial mammals. For it is
a general Natural History rule that animals go
back to their old home to breed. What is
seen on a small scale on British shores is seen
magnified elsewhere ; for instance in Alaska,
where the fur-seals have their great rookeries.

On other British shores the otter has its
home, or rather one of its homes, for otters are
roving animals. They often swim several miles
to reach an island off the coast ; they can dive
more than full fathoms five to catch the plaice
lying on the sandy floor of the bay ; when
they are severely rationed they pick about

PLATE II. — TERNS OR SEA-SWALLOWS, FLYING ON THE SHORE.

Note the very long- wings and the forked tail. On the dunes three eggs may

be seen in a little scraping on the sand.

THE SCHOOL OF THE SHORE n

among the rocks, not disdaining limpets and
mussels.

Besides seals and otters there are other
mammals that frequent or may frequent the
shore. The polar bear in the Arctic regions
sometimes lies down beside an opening in the
thick ice and waits for a seal to come up to
breathe. With one stroke of its great arm it
has been known to lift the seal right out of the
water, and send it crashing over the ice in-
stantaneously killed. The walruses, also of
the North, dig up the bivalves with their huge
tusks. Along warm coasts the dugongs and
manatees, jointly known as sea-cows, browse
on the seaweeds. But we have said enough :
the shore-fauna includes mammals.

BIRDS. — There are many birds characteristic
of the shore, especially at certain seasons. We
think of gulls and terns, dunlins and sand-
pipers, curlew and whimbrel, shag and cor-
morant, and many others — a fine account of
which will be found in Mr. W. P. Pycraft's
delightful book The Sea Shore. We can only
select a representative. The oyster-catcher is
often to be seen where there are limpets and
mussels in abundance. The black and white

12 THE HAUNTS OF LIFE

plumage, the ruddy legs, the red and yellow
bill, the shrill cry, the rapid flight, make it very
conspicuous. It breaks a hole in one valve of
the mussel's shell, and inserting its bill scoops
out the palatable flesh. With a dexterous
side-stroke of its strong bill it can jerk the
limpet off the rock ; but to do this, as everyone
knows who has tried, it is necessary to take the
mollusc unawares and to strike quickly.

REPTILES. — There is a marine lizard
(Amblyrhynchus) on the Galapagos Islands
that swims out to sea and dives after seaweed.
There are sea-snakes that come ashore to
bring forth their young. Crocodiles and
alligators may be found on the shores of
estuaries. The sea-turtles bury their eggs in
the sand of sun-baked shores.

AMPHIBIANS. — There seems to be something
about salt that is prejudicial to amphibians.
Thus they are not found near the sea and are
unrepresented on Oceanic Islands, where the
tenants are restricted to those creatures that
could survive being drifted on logs and the
like, or could be carried by birds or the wind.
But we are reminded of the danger of hard-

THE SCHOOL OF THE SHORE 13

and-fast statements by the fact that there is a
frog at Manilla which is often seen hopping
about on the shore.

FISHES. — The shore-fishes are legion, but
some are more characteristic than others. One
of these is the Gunnel or Butterfish (Centra-
notus gunnellus), so extraordinarily difficult to
catch because of its power of insinuating itself
between the stones and into crevices, so extra-
ordinarily difficult to hold when one has caught
it, such is its slipperiness. The father-lasher
and the sand-eel, the cock-paidle and the
stickleback are also common on the shore.

SEA-SQUIRTS. — Fastened to the long flag-like
seaweeds there are often groups of Ascidians
or Sea-Squirts, strange degenerate creatures
which cross the frontier into the backboned
sub-kingdom in their free-swimming youth, but
sink back again, as it were, when they grow up
and settle down. On the stones at low tide
there are often very beautiful colonies of com-
pound Ascidians or Tunicates, quite jewel-like
sometimes in their fine colouring.

MOLLUSCS. — Highest in a way among back-
boneless or Invertebrate animals are the

14 THE HAUNTS OF LIFE

Molluscs — the bivalves, snails, and cuttlefishes ;
and these — especially the first two classes — are
well represented on the shore. Bivalves are
represented by cockle and mussel, oyster and
clam ; snails by the vegetarian periwinkle and

limpet, and the carni-
vorous dog -whelk and
buckie ; cuttlefish by an
occasional octopus hunt-
ing for crabs among the
low - tide rocks. Even
Aristotle knew, over two
thousand years ago, how
a shore cuttle shoots out
an arm and grapples a
passing fish.

ARTHROPODS. — On
quite a different line of
life from the Molluscs
FIG. i.— THE KING-CRAB, are the Jointed- Footed

LlMULUS. ... , . •... '

A very ancient Shore Animals Or Arthropods,

Arthropod. represented on the shore

by Crustaceans, such as crab and hermit-crab,
sea-slater and sand-hopper, acorn-shells and
water-fleas. Clambering about on the sea-
weeds and zoophytes there are quaint " Sea-

THE SCHOOL OF THE SHORE 15

spiders " or Pycnogons, perhaps related to both
true spiders and Crustaceans. A few true
spiders among the rocks, some insects near
high - tide mark, and an occasional centipede
must also be included in the shore-fauna.

WORMS. — The higher worms or Ringed
Worms (Annelids) are well represented on the
shore ; but one must dig to see the best of them.
Thus the yard-long many-footed Nereis virens
burrows in the sand close to the rocks ; the
castings of the fisherman's lobworm (Arenicola)
are much in evidence on the flat beach ; the
strange sea-mouse {Aphrodite), shaggy with
iridescent bristles, is often cast up from greater
depths. The sand-binding worm (Lanice con-
chilega) makes tubes of sand-particles neatly
fastened together ; the lime-tubes of Serpula
are common on shells, and of Spirorbis on
seaweed.

Besides the higher worms or Annelids, with
a ringed body, there are many others of lower
degree. Where there is rotting we may find
thousands of small threadworms or Nematodes,
and in the shore-pools there are Planarians or
"living films "which glide along mysteriously
by means of invisible lashes or cilia.

1 6 THE HAUNTS OF LIFE

OF UNCERTAIN POSITION. — There are many
seashore animals whose relationships are
obscure. Thus there are the Polyzoa, to which
the common Sea- Mat (Flustra) belongs — the
animal on which Darwin wrote his first scientific
paper. The Polyzoa form a large class, with
a great variety of representatives, some sea-
weed-like (Flustra), till you look into them ;
some coral-like (Cellepora) ; some gelatinous
(Alcyonidium)] some like zoophytes (Gemel-
aria), but ever so much higher in structure.

ECHINODERMS. — The prickly skinned animals
are represented by star-fishes, brittle-stars, sea-
urchins, and sea-cucumbers, forming a well-
marked " kenspeckle " class, with a great
tendency to become very calcareous, least so in
the sea-cucumbers, most in such sea-urchins as
the sand-dollar. It is a most interesting sight
to watch the common star-fish creep up the
vertical surface of a submerged rock by means
of its remarkable hydraulic locomotor system,
while the sea-urchin, when moving on a flat sur-
face, hobbles along on the tips of its five teeth !

STINGING ANIMALS. — Sea-anemones nestle
like flowers in the niches of the rocks. In

THE SCHOOL OF THE SHORE 17

deeper water there are Alcyonarians, such as
Dead-Men's-Fingers, often thrown up in great
quantities after searching storms. In warmer
seas the branched Sea-fans or Gorgonians are
very common. Everywhere there are zoophytes
or hydroid colonies, some of which give off
swimming-bells or medusoids in the summer
season. When a Stinging Animal (or Ccelen-
terate) becomes very calcareous it is called a
coral, and so there are corals related to sea-
anemones (such as reef-building corals and cup
corals), others related to Alcyonarians (such
as the precious red coral and the organ-pipe
coral), others related to hydroids (such as the
close-grained millepores).

SPONGES. — Apart from the family of fresh-
water sponges (Spongillidae) — doubtless emi-
grants from the shore — all sponges are either
shore-animals or deep-sea animals. In other
words, they are sedentary and require a sub-
stratum on which to grow. The Crumb-of-
Bread Sponge (Halichondria panicea] grows on
the shore-rocks, with exhalant openings like
the craters of volcanoes ; the Purse Sponge
(Grantia compressa) often has to endure pro-
longed exposure at low tide ; the Bath Sponge

1 8 THE HAUNTS OF LIFE

(Euspongia), found in the Mediterranean, the
West Indies, and Australia, often grows at
depths readily reached by a long fork.

SIMPLEST ANIMALS. — Very abundant on
some shores are almost microscopic chalk-
forming animals or Foraminifers which glide
about on seaweed by means of outflowing and
retractile threads of living matter. In all the
pools and shore-waters there are many kinds
of Infusorians, which propel themselves rapidly
by means of lashes of living matter (cilia or
flagella).

Any book on shore Natural History will
supply information about the animals on our
list. The meaning of the list is just to show
that the shore gives hospitality to a very repre-
sentative assemblage of animals. We add a
scheme of classification, which may be useful
at different parts of our study, to show how
certain animals stand in relation to others.

A DIFFICULT PLACE TO LIVE IN

The school of the shore is a hard school.
It must be an interesting and stirring place to
live in, but no one could call it easy. There

THE SCHOOL OF THE SHORE

THE ANIMAL KINGDOM

BIRDS.
rlying Birds. Running Birds.

Placentals.
MAMMALS. «£5*£
Monotremes.

MANY-CELLED ANIMALS, WITH BODY.

BACKBONED.

Snakes. Lizards. REPTILES. Crocodiles. Tortoises and
New Zealand "Lizard." Turtles.

Mud-Fishes.

T?TCTJT7c Bony Fishes.
FISHES. «<G^noids>>.

Gristly Fishes.

Frogs.
AMPHIBIANS.

Newts. Csecilians.

ROUND MOUTHS.
Hag. Lamprey.

LANCELETS.

SEA-SQUIRTS.

BACKBONELESS.

Spiders.
Scorpions.
Mites.
Insects.
Millipedes.
Centipedes.
Peripatus.

Balanoglossus, etc.

Cuttlefishes.
Gasteropods.

MOLLUSCS.
Bivalves.

HIGHER WORMS
OR ANNELIDS.

SMALL CLASSES.

SMALL CLASSES.

SMALL CLASSES.

ARTHROPODS.
Crustaceans.

LOWER WORMS.

Feather-stars.
Brittle-stars.
Star-fishes.

ECHINODERMS

Sea- Urchins.
Sea-Cucumbers.

Comb Bearers Jelly-fishes. Sea- Anemones and Corals,
or Ctenophores.
STINGING ANIMALS.

Swimming Bells and Zoophytes.

SIMPLEST ANIMALS,
infusorian, ^^

SPONGES.

and Malaria-animal,
and the like.

gf*

S°

20 THE HAUNTS OF LIFE

are stormy days when the waves are literally
breakers. There are fresh-water floods from
inland, smothering masses of jetsam from the
sea, and clouds of wind-driven sand from the
beach and the dunes. In the polar regions
there are difficulties due to the ice ; in the
equatorial regions there are difficulties due to
the scorching sun.

Many problems are presented by the differ-
ences between tide in and tide out : animals
that have been bathed in water for many hours
are left high and dry. Let us look at a few
of the solutions.

All animals require oxygen to keep the vital
processes agoing, for there is no living without
combustion. Oxygen is required to keep the
fire of life burning. Now marine animals find
the indispensable oxygen mixed with the water,
and seashore water, where there are waves, is
very rich in oxygen. But an animal accus-
tomed to use the oxygen mixed with the water
cannot suddenly change and become able to
use the oxygen mixed with the air. This is
one of the problems raised by the outgoing
tide.

The Purse Sponge (Grantia compressa)

THE SCHOOL OF THE SHORE 21

keeps a big bubble of water in the cavity of
its body, and this serves to mediate between
the living cells and the dry air. The bivalves,
like mussels and oysters, keep the two halves
of the shell firmly closed, and imprison enough
of sea- water to keep the delicate gills and skin
moist for many hours. While the mussels are
uncovered at low tide the shells are never
opened, and the animal remains quiet, not
feeding, scarcely breathing, simply waiting
until the sea returns. Periwinkles, buckies,
and many other sea-snails have a very effective
way of closing their shell by means of a hard
plate attached to the hind end of the muscular
"foot." When the animal withdraws into its
shell, this lid (operculum) closes the mouth of
the shell and fits very neatly. If we watch a
periwinkle walking about on the floor of a pool
we see that it glides along on its "foot," and
that the head with its horns is also protruded.
But if we pick it up the head and the foot are
immediately withdrawn, and the animal is safe
behind its closed door.

The limpet needs no door to its shell, because
it clings so firmly to the rocks by its sucker-
like foot that it is very difficult to dislodge.
Its shell is so thick that the water within it

22 THE HAUNTS OF LIFE

does not evaporate, and the limpet is safe, too,
from being injured by the waves. But it is
not altogether safe from other animals, for
some birds, especially the oyster-catcher or
sea-pie, have discovered exactly the kind of
sudden sharp stroke of the bill that is needed
to knock a limpet off its rock, and once it has
let go its hold it is a helpless victim. When
the tide covers the limpet's rock it relaxes its
hold and slowly moves off on its foot to the
nearest seaweed patch where it cuts, with the
long, toothed, rasping ribbon or file in its
mouth, the grassy blades on which it feeds.
Before the tide has ebbed it makes its way
back to its rock, if it has not wandered too far
and lost its way, and fixes itself in the exact
spot in which it was before. In some cases it
keeps to this spot so persistently that a little
pit corresponding in size and shape to its shell
may often be seen in the rock. Where all the
rock is smooth the limpet does not trouble to
return to its starting-point, for every spot is
very much the same.

Some molluscs, whose shells are not large
enough to enclose them comfortably, or to
protect them effectively, have learnt to bury
themselves in the sand, and so to secure

THE SCHOOL OF THE SHORE 23

moisture and safety. The animal which lives
in the familiar razor-shell of our shores burrows
straight downwards with its foot into the sand,
where it lies so well concealed that it is not
easy to discover it alive. For even if we see
above the sand the little jet of water it shoots
up from time to time through its breathing
tube, the animal burrows away so rapidly that
it is not easy to reach it.

Still more remarkable is the fact that some
bivalves, such as the one known to fishermen
as the piddock, burrow, or rather bore, into
the rocks themselves. We can see their holes
very easily, especially when the rock is one of
the softer kinds such as sandstone, and we
may sometimes see the breathing tubes of the
piddock at the mouth of its long burrow ;
but these are very quickly withdrawn as we
approach. The hole is too narrow and long
for a crab's claw or a bird's bill, and the animal
can only be got at by breaking open the rock.

This mollusc uses its "foot" for burrowing
into the rock just as its sand-burrowing rela-
tives do ; but there is a difference in the foot.
Though it looks quite soft, it has, embedded in
its muscular substance, a layer of sharp, hard
crystals, and these slowly wear away the rock

24 THE HAUNTS OF LIFE

as the animal patiently scrapes. The crystals
in their turn are worn away by the rock ; but
they are continually being renewed. Thus by
means of this adaptation the boring Pholas
secures three things : first, the necessary
moisture and shelter from sun or frost to
keep it alive while the tide is out ; second,
security from being dashed to pieces by the
waves ; and third, relative safety from the
attacks of hungry enemies.

Molluscs are not the only animals that have
learnt these ways of protecting themselves.
Many worms burrow in the sand, and a few
bore into the rocks. Flexible worms cannot
have shells in the strict sense, for shells are
made by the living skin ; but they often build
round their bodies sheltering tubes of lime or
of grains of sand, or bits of shell or other
substances cemented together, and they with-
draw their delicate tentacles into these when
danger threatens. Fragments of the different
kinds of tubes made by different kinds of
worms may often be picked up on the shore.

Crabs and some of their relatives have also
the habit of burrowing in the sand, shovelling
it aside with their great claws or with their
legs. The big crabs, indeed, do not need this

THE SCHOOL OF THE SHORE 25

habit much for protection, for their thick, hard
shell covers the gills and prevents evaporation ;
they are sufficiently active to be able to get to
a pool or a sheltered crevice under a rock
whenever occasion arises ; and their strong
claws and pugnacious spirit are enough to
keep off most enemies except still bigger crabs.
Some of the other members of the family,
however, such as the burrowing prawns,
tunnel in the sand near low-tide mark, and live
an almost underground life.

THE STRUGGLE OF THE SHORE

A haunt with a crowded population of all
sorts and sizes, a haunt where the most
constant thing is change, a haunt bristling
with difficulties and hemmed in by limitations ;
there is bound to be much struggle on the
shore. But we should try to make it clear
to ourselves that the " struggle for existence"
is a technical phrase which includes much
more than a life-and-death competition around
the platter, much more than what we get a
symbol of when the pigs elbow and jostle one
another at the feeding-trough ; it includes all
the answers-back that living creatures make

26 THE HAUNTS OF LIFE

to the difficulties that beset them and the
limitations that hem them in.

The struggle on the shore is partly for food
— some of which is always being carried out
to sea ; partly for foothold — for a good niche
is a treasure ; partly for the oxygen mixed
with the water — the oxygen which is always
necessary to keep life going ; partly against
risks of dislodgment, smothering, and drought ;
partly to get elbow-room in self-expres-
sion ; and partly to secure the safety and
welfare of the young ones. The " struggle"
is sometimes an endeavour after well-being.
It may be with fellows of the same kind — one
hermit-crab against another ; it may be with
foes of quite different race — mussel against
star-fish, limpet against oyster-catcher ; it may
be between animals and Fate — the physical
forces of wind and wave, of sand and sun.
The struggle is manifold.

In our study of the Wonder of Life (1914)
we have referred to the struggle for foothold
on the shore. " It is important, for instance,
that the limpet, which makes little journeys in
search of seaweed to nibble, should not go too
far, else it will not find its way back, and will
have lost the spot which its shell has grown

THE SCHOOL OF THE SHORE 27

to fit. It is curious, too, to see the American
Slipper- Limpet (Crepidula) — one growing on
the top of another to the number of four or
five — suggestive of the root-idea of a sky-
scraper." It is very interesting to take a stone
from a deep pool, or from the floor of the sea
in shallow water further out, to see how many
different kinds of creatures take advantage of
this pedestal. One stone from Clare Island
bore fourteen different kinds of " moss-animals "
or Polyzoa.

Truly, the shore is a place of struggle. Is
there any other haunt where we see so clearly
the truth of Tennyson's words —

"That life is not as idle ore,
But iron dug from central gloom,
And heated hot with burning fears,
And dipt in baths of hissing tears,
And batter'd with the shocks of doom

To shape and use."

In Memoriam.

Some one said long ago that a great part of
life is connected with the conjugation of the
verb : To eat ; and we realise how true this is
when we study the life of the shore. " I eat,
thou eatest, he eats . . . they eat." " I shall
eat . . . they shall eat." " I have eaten . . .
they have eaten." "They have been eaten."

28 THE HAUNTS OF LIFE

It is fairly safe to say that no seashore animal
ever says, what a man might say with a shark
after him : " I shall be eaten." It is certain
that none ever says : " I have been eaten."
There is grim truth in this saying about the
conjugation of the verb : To eat ; but the truth
is one-sided unless we remember that the
animals are also conjugating the verb : To love,
and often, also, the verb to conquer. " Love"
and " Hunger," both in inverted commas, are
the pivots on which all life swings.

THE CIRCULATION OF MATTER

Animate nature is run on what may be called
a scheme of successive incarnations. Matter is
always passing from one embodiment to another,
and nothing is ever lost. The minute plants
free in the water and the fixed seaweeds, great
and small, all feed on the sea itself and the air
which it holds in solution. They are bathed in
a nutritive solution of salts and gases, which
their living matter, with the help of the sun-
light, lifts on to the plane of life. In technical
language, they build up carbon-compounds by
photo-synthesis.

But animals get their food from the plants,

THE SCHOOL OF THE SHORE 29

or from remains of the plants, or from other
animals which have fed on plants. So one
incarnation or embodiment follows another in
long chains, and this is the circulation of
matter.

It has been calculated that —

One pound of cod means that the cod, to

make it, had to eat ten pounds of

whelk or buckie ;
One pound of buckie means that the

buckie, to make it, had to eat ten

pounds of sea-worms ;
One pound of worms means that the

worms, to make it, had to eat ten

pounds of vegetable sea-dust.
We mean by the vegetable sea-dust the

microscopic plants and their remains.

Sometimes the chain is longer, sometimes
shorter, but we cannot understand the economy
of the sea at all until we get a firm grip of the
idea, which the chemist Liebig first made vivid,
of the circulation of matter. It is a modern
version of what one of the Greek philosophers,
Heraclitus, said : ALL THINGS FLOW.

30 THE HAUNTS OF LIFE

CANNIBALISM IN THE CRADLE

The struggle for existence means all the
answers-back that living creatures make to
surrounding difficulties and limitations. It
includes experiments in co-operation and
mutual aid, as well as experiments in com-
petition. At one time it may take the form
of increased parental care ; at another time
it may mean a sharpening of teeth and
claws.

We must not blink those cases where the

struggle is terribly keen — for immediate life or

death. Let us take an instance. Fastened to

the rocks there are great bunches of chaffy

capsules — the egg-cases of the Great Whelk or

Roaring Buckie (Buccinum undatum), whose

shell children hold to their ears. Sometimes

the bunch, made by several whelks working

together, is as big as one's head. In each

capsule there are many developing eggs, and as

these hatch out into larvae they turn upon one

another. Those furthest advanced eat the

others — the leaders the laggards — till only a

few are left in each capsule. This is struggle

to the death at the very threshold of life. It

is cannibalism in the cradle. The empty

THE SCHOOL OF THE SHORE 31

bunches are often torn off by the waves and
thrown up on the beach. If a capsule is care-
fully examined, an opening will be seen on the
inturned flatter side — the opening by which
the surviving larvae emerged. The same grim
story is true of the neat vase-shaped capsules,
first pinkish and then straw-coloured, which the
small Dog Whelk (Purpura lapillus) fastens to
the rocks, very often to the under side of a
shelf. Many are called into life, but few are
chosen to survive.

SHORE SEAWEEDS

It is a great sight when the seaweeds are
uncovered on a rich foreshore at the lowest
tide of the year. If we put on old clothes and
boots and wade out among them, very, very
cautiously, because of the slipperiness and the
danger of concealed deep holes, we get our
reward, especially if we take scientific imagina-
tion as our staff. We find ourselves in the
midst of a rich and varied vegetation, part of
which is older than the hills. . We are in the
midst of the plants of the early ages of the
earth's history.

A distinguished Oxford botanist, Dr. A. H.

32 THE HAUNTS OF LIFE

Church, has pictured three great chapters in
the history of plant-life.

(I.) After the earth had greatly cooled down,
the condensation of the water vapour formed a
great sea covering the whole surface of the
earth. In this sea there lived minute single-
celled or bodiless green plants, each sufficient
unto itself. Some of these Plankton plants
were the ancestors of those which now abound
near the surface of the Open Sea.

(II.) By and by the buckling of the sea-
covered earth's crust brought part of it within
reach of the light, and supplied an illumined
sea-floor on which plants could fix themselves
and grow big. This was the beginning of the
shore vegetation, the beginning of a substratum,
the beginning of what we ordinarily call sea-
weeds. And as they were fixed creatures, it
was necessary for them to show, not only
means of self-preservation, but means of dis-
persal, ways of continuing their kind. Some
of the free-swimming plants that settled down
grew long threads, others spread out into
fronds, others forked and branched like the
most beautiful lace. Ages passed, and there
was a great race of seaweeds. Some of those
now living are a hundred feet long.

THE SCHOOL OF THE SHORE 33

(III.) According to Dr. Church's interpreta-
tion, the gradual raising of the sea-floor in
certain places led to the first dry land, and
some of the seaweeds, which had become very
complex plants, were transformed into land
plants. If this is true, it was a great change.
The roots of seaweeds are only anchors or
hold-fasts ; they would require to be equipped
with rootlets and root-hairs for absorbing the
water and salts from the young soil. And the
whole surface of the sea-plant, suited for ab-
sorbing water and salts all over, would have to
become the gas-absorbing surface of the land-
plant. Moreover, there would need to be a
system of vessels inside the pioneering land-
plant for transporting the raw materials and
the manufactured materials from one part of the
plant to another ; and this is only beginning in
seaweeds.

Of course, when we speak of transformation,
we must not think of the old stories of the
yellow frog who was suddenly turned into a
fairy prince, or of the followers of Diomede
turned into birds, which a scholar-naturalist
has identified as Shearwaters. Nature's is no
quick magic, but here a little change and there
a little change, so gradually, so slowly, that if
3

34 THE HAUNTS OF LIFE

living man had seen the transformation he
would have said that the living creature was
not changing at all.

Whatever the history of seaweeds may have
been, they are splendid and beautiful plants
to-day — not half enough appreciated. But with-
out saying more about this we may notice an
important fact in regard to their colours. The
green seaweeds are nearest high-tide mark ;
lower down the brownish ones are in the
majority ; most of the red ones are in still
deeper water. All the three sets have got the
precious green pigment or chlorophyll, which
enables the plant to utilise the energy of the
sunlight ; but in the brown and red seaweeds
the green is disguised by other pigments.
Some say that these other pigments help the
plant to make the most of the decreasing light,
and that red is better than brown. So the red
seaweeds are most abundant in the deepest
waters where the light is least.

FOOD-GETTING ON THE SHORE

What food supplies are available for animals
on the seashore ?

(i) There are, first of all, the living seaweeds

THE SCHOOL OF THE SHORE 35

on which some animals browse, such as the
Pellucid Limpet (Helcion pellucidwn), well
known for its beautiful blue-marked shell.
Some animals that look as if they were eating
the seaweed are feeding on microscopic plants
on the surface of the fronds. Along with the
seaweeds we must take the sea-grass, Zostera,
a flowering plant very abundant in some shore
waters. (2) There is, secondly, the result of
the breaking down of seaweeds and sea-grass,
the vegetable debris, the plant-dust. (3) There
is, thirdly, the multitude of minute free-swim-
ming and free-floating plants, such as Diatoms
and Desmids. These are exceedingly abundant
in near-shore waters, and get swept out to form
Open-Sea Plankton. The shore-waters serve as
a nursery for the Open Sea abundance of minute
plants. (4) There are the minute free-swim-
ming animals, some of which are hardly dis-
tinguishable from plants. (5) There is the
material, both animal and vegetable, brought
down from inland by rivers and streams, some-
times helped by the wind. We are not includ-
ing the mineral matter brought down which
serves to feed the shore plants. (6) There is
the jetsam brought in from the sea, for the
receding tide sometimes leaves on the beach

36 THE HAUNTS OF LIFE

countless numbers of creatures that have come
too near the shore. We have seen a brownish
line of millions of the pinhead-like Noctiluca
extending far along the sand.

Sometimes there is an unexpected windfall
of food ! Thus one writer tells us that a
hurricane lasting for days, at the time that a
particular moth (called the nun) was swarming,
blew such numbers of these out to sea, that,
when they were washed up by the tide, their
dead bodies formed a wall 6| feet broad and
6 feet high, which stretched for many miles along
the shore. The same kind of thing has been
noticed many times in warmer regions, when
the locusts were caught in a storm during their
migration.

But there is one thing we must remember
about the abundant supply of food on the sea-
shore— it is not very regular, and it never lasts
long at a time. The incoming tide may throw
it up one day and the outgoing tide may carry
it away the next — carry it so far that it is
never brought back again. For if it gets
beyond the shallow-water area it sinks to the
bottom at the " mud-line." It is not wasted
even then — " Nature is ever a careful house-
keeper " ; but it is no longer available for the

THE SCHOOL OF THE SHORE 37

shore animals. So these have to be on the qui
vive ; they must feed while they can, and take
as much as they can. No doubt they can get
a good living, but they cannot get it easily.
One of the most important lessons that the
inhabitants of the shore have to learn is to be
always on the alert, and to make the most of
their chances.

Let us take some particular cases of food-
getting. Encrusting the rocks in many places
there is the Crumb- of- Bread Sponge (Hali-
chondria panicea) with large exhalant apertures
where the water is swept out, and minute pin-
prick holes all over the surface by which the
water is swept in. After their early youth is
past, sponges are fixed animals, and one natu-
rally thinks of them as easy-going. But they
have to work hard for their living. They
obtain their food from microscopic creatures
and nutritive particles in the water, and in order
to get enough they have to pass large quanti-
ties of water through their body every day.
If an animal's body be compared to a city, and
the tissues to streets, and the cells composing
the tissues to houses and workshops, and the
jostling particles of living matter inside the cells
to the people themselves, we would compare a

38 THE HAUNTS OF LIFE

sponge body to a city like Venice, which is
traversed by canals, bringing in food and useful
materials, and carrying away waste. For the
sponge's body is traversed by inhalant canals,
bringing in food and oxygen (both carried by
the water), and bearing out useless particles
and waste products. The water, as we have
said, passes in by minute pin-prick holes all
over the surface of the sponge ; it passes out
by the large openings often about the diameter
of a lead-pencil. If a glass tube be carefully
fitted into one of these exhalant apertures, and
one need not be afraid of hurting the sponge,
the water will be forced up into the tube above
the level of the surface of the pool. Where
does the force come from ? The pressure is
due to the ceaseless activity of lash-bearing or
flagellate cells, situated in chambers at the
junction of the inhalant and exhalant canals.
On their lashing the whole life of the sponge
depends. Does it not work hard for its living ?
The sea-anemones nestling in the niches of
the rocks, some of them like chrysanthemums
when spread out, how do they get their food ?
They wait for creatures, e.g. small crustaceans,
to touch their expanded tentacles, which are
covered with explosive stinging-cells and

THE SCHOOL OF THE SHORE 39

grappling-cells. Just as we draw back our
finger from a hot plate without even willing
it, because of a circuit between nerve-cells that
feel, nerve-cells that command, and muscle-cells
that obey, so the sea-anemone folds its tentacles
about an incautious worm. This is called
reflex action. The sea-anemone may be
deceived by giving the tentacles a little roll
of wet paper to catch ; but after it has been
cheated twice or thrice it has had enough and
will not close up any more. Sometimes it
catches too big an animal, like a periwinkle,
which struggles hard and bursts through the
enswathing tentacles. The sea-anemone can
flourish for a long time without more than
microscopic food ; it might be called an easy-
going feeder. One has been known to live
for sixty years.

Right up to the high-tide mark on rocks,
pillars of piers, stray pieces of wood, and even
on living animals, like crabs, we see a crusting
of rock-barnacles or acorn-shells. When the
tide is out the roof of the rampart that encloses
the animal is kept tightly shut ; but as soon as
the water, or even the salt spray, reaches it,
the acorn-shell opens its four valves. When
it is covered with water it begins to feed with-

40 THE HAUNTS OF LIFE

out losing a minute, and we are rewarded if we

kneel down beside a pool and watch operations.

From between the valves there are protruded

FIG. 2.— ACORN-SHELLS OR ROCK-BARNACLES (BALANUS).
Of two kinds, large and small. Notice the Outer Rampart, the
Movable Roof of four pieces, and the six pairs of Curled Feet
wafting the Food into the Mouth.

six pairs of curl-like, bristle-bearing limbs,
each with two branches ; and with this sifting
net the little crustacean sweeps the water,

THE SCHOOL OF THE SHORE 41

wafting minute creatures and nutritive particles
into its mouth. Professor Huxley compared
the acorn-shell to a shrimp fixed head-down-
wards, and kicking its food into its mouth with
its legs. But it is a peculiarly graceful kind
of kicking ! Many of them must expend much
energy before they sift out a meal from the
clear water. They live in castles ; but not
castles of indolence. The acorn-shells are
relatives and probably descendants of the
stalked barnacles which fix themselves to
wooden ships and floating logs. Like these
they are free-swimming in their early youth ;
but they fix themselves eventually by their
feelers and settle down. A rampart of lime
is formed round about, and the animal is
cemented down for the rest of its life. Not a
very exciting life, perhaps, but a very safe
one, for no waves are strong enough to wash
the barnacle from its rock. Sea-urchins have
meals of barnacle when they are tired of sea-
weeds, and dog-whelks also browse on them ;
but they hold their own well. Their eggs are
washed out by the tide and hatch in the open
water, and there we also find the transparent
feather-like moults of the adults which have
been cast in the pools.

42 THE HAUNTS OF LIFE

Sponges, sea-anemones, acorn-shells are fixed

animals, and they depend for food on what

they can sweep in from the water, or on what

they can catch as it passes by. But we must

take some examples of more vigorous ways of

feeding on the part of animals which roam

about from place to place. The periwinkles,

such as Littorina littorea, which is one of the

poor man's "oysters," creep about browsing

on delicate seaweeds, and it may be noticed

that those sea-snails which have an unbroken

outline to the mouth of their shell are vegetarian,

while those with a deeply in-cut notch at the

mouth of the shell (a groove for the protrusion

of a breathing tube) are carnivorous. The

vegetarian Gasteropods are palatable ; the

carnivorous ones hardly ever. So if we are

wrecked on a desert island we must begin our

seashore meals with those sea-snails that have

no notch at the mouth of their shell.

Very different from the periwinkles are the
whelks and "buckies" which roam about in
search of animal food. We often find on the
sandy beach one of the valves of a bivalve
shell, e.g. Venus gallina, with a hole neatly
bored through it, as neatly as if it had been
made by a gimlet. In many cases this hole

THE SCHOOL OF THE SHORE 43

has been made by a carnivorous Gasteropod
called Natica, which has a boring gland on the
underside of its proboscis. This gland is
pressed against the bivalve shell and the
sulphuric acid which it secretes dissolves a
hole right through. When the perforation is
made, the borer often uses its rasping ribbon
to enlarge it.

THE STORY OF THE ANGLER

One of the queerest of queer fishes is the
Angler or Fishing Frog (Lophius piscatorius]
— a fish that fishes. It is rather a lazy creature,
of long pedigree, and of big appetite. In
shallow water off-shore it often shuffles along
with its strong fore-fins and settles down on
an open space among the seaweed. Curious
tags of skin about the head and body are very
like waving fronds of seaweed, and that is all
to the good. The first three fin-rays of the
dorsal fin are long separate rods, and the first,
which is particularly mobile, bears a lappet of
skin dangling at the free end — the bait at the
end of the angler's line. Circumstantial
evidence points to the conclusion that the
angler really fishes with its fishing-rod. In

44 THE HAUNTS OF LIFE

some of its deep-sea relatives the bait or
lure is luminescent. Fishes are often attracted
to dangling objects, which doubtless pull the
trigger "Food." But whatever be the precise
use of the fishing-rod there is no doubt that
the angler catches many fishes.

The creature's head is extraordinarily broad,
and its gape is a terror. The angler seems
" All Mouth." A fatal gape it is, for the sharp
teeth along the jaws point backwards and are
hinged at their base, yielding at once if we
press them inwards, but rising in opposition if
we draw our finger the other way. What a
simple trap, and yet so subtle ! A broadening
out of the jaws is not very remarkable ; but
add to that a fishing-rod and a loose-hinged
attachment of the backward-pointing sharp
teeth. If the incautious victim has begun to
explore what must seem to it just an interest-
ing opening below the dangling lure, there is
no return. In some cases the Fishing Frog
manages to submerge much of its clumsy
body in the sand. The dorsal fin-rays stand
out in all innocence ; the bait dangles above
the mouth ; the victim indulges its scientific
spirit of investigation — and then the trap snaps.

The eggs of the angler are found floating

THE SCHOOL OF THE SHORE 45

in the open sea, embedded in little compartments
in a big drifting sheet of violet-grey slime,
many feet long. After a while the eggs
become separated from the sheet and float
singly. The newly hatched young one floats
also, with its heavy head downwards (see Fig.
7, p. 93), and the tip of its tail just touching
the surface film. It is still living on the yolk
of the egg which is uppermost in the water.
After a fortnight has passed the yolk is
exhausted ; the young fish is superficially like
a tadpole ; it opens its mouth and begins to
fend for itself. For a long time, however, it
lives an Open-Sea life, and it has an extra-
ordinary appearance, due to the elongation of
its fin-rays into flexible streamers. These
have the same use as the slime round the eggs,
they secure flotation, first at the surface, and
then in the upper layers. This is, on the whole,
a very safe cradle, and there is an abundance
of living minutiae to eat. Gradually the head
of the larval angler broadens out enormously
behind the eyes, and these are shifted to the
top. The seaweed-like tags of skin become
numerous, the long fin-tassels disappear. The
young fish comes near shore and sinks to the
bottom — there to remain for the rest of its life.

46 THE HAUNTS OF LIFE

THE STAR-FISH AND SEA-URCHIN FIGHT

The star-fish is a soft-mouthed animal, with-
out anything in the way of teeth or jaws, but
it is a thoroughgoing carnivore. It does much
harm on the oyster-beds, engulfing the small
oysters in its capacious protrusible stomach.
It is fond of mussels, and it can actually open
the valves by hunching itself up above the
mussel and persistently pulling in opposite
directions with the suctorial tube-feet of two
of its arms. But who would think of a star-fish
tackling a small sea-urchin, covered all over
with spines like a hedgehog, and equipped
with hundreds of little snapping blades (called
pedicellariae), like scissors with three blades.
When these snapping spines are touched, they
clinch ; and some of them are poisonous.

Nothing daunted, if we dare use such a
phrase in regard to an animal that has not a
vestige of brains, not even one nerve-centre,
the star-fish lays one of its arms on the prickly
sea-urchin. The hundreds of tube-feet on the
under surface of the arm are promptly nipped by
the sea-urchin's snapping spines. The star-fish
withdraws its arm, and the snapping spines,
unable to let go, are wrenched off. Then

THE SCHOOL OF THE SHORE 47

another arm is used, and another, and another,
until the star-fish has disarmed the small sea-
urchin. Then out comes the elastic digestive
stomach. This shows remarkable persistence
on the part of a brainless animal.

SHIFTS FOR A LIVING ON THE SHORE

Of all the haunts of life the shore is most
varied in its life-saving devices. We like to
call them " shifts for a living," because they are
on so many different levels of behaviour. In
some cases the animal probably knows what
it is doing, in some dim way at least, as when
a crab deliberately rubs pieces of seaweed on
the back of its shell so that they catch on the
bristles and grow there. In other cases the
animal probably does not know what it is
doing, as when the star-fish surrenders an
arm that is seized.

What an armoury of weapons there is on the
shore — stinging-cells of sea-anemones, the lasso
of a ribbon-worm, the forceps of a crab, the
rasping file of a whelk, the parrot's-beak-like
jaws of a cuttlefish, and so on up to the tusks
of a walrus. What are variety of armour too,
— the prickly test of a sea-urchin, the ornate

48 THE HAUNTS OF LIFE

carapace of a rock-lobster, the unbreakable
shells of molluscs, the scales of fishes often
sharp and formidable, and so on up to the
complicated encasement of the edible turtle.

MASKING

The " walking wood of Birnam " was an
episode in Scottish history, immortalised in
Shakespeare's Macbeth, where a band of soldiers
camouflaged themselves by cutting down
branches of trees and carrying these with
them as they stealthily advanced. So some
crabs on the seashore fix seaweeds on the back
of the shell and mask themselves effectively.
They can steal upon their victims ; they can
efface themselves in the eyes of their enemies.
Sometimes the cloak consists of zoophytes, or
pieces of sponge, or half of the tunic of a sea-
squirt ; but oftenest it is a cloak of seaweed.
1 1 is as if the crab carried a garden on its back.
The camouflaging is often shown by the sand-
crab (Hyas araneus) and by the narrow-beaked
crab (S tenor hynchus longirostris) ; but it is seen
in many others. The disguising seems very
deliberate on the crab's part, and if the disguise
is picked off, the crab often sets about clothing

THE SCHOOL OF THE SHORE 49

itself again. One of the hermit crabs (Pagurus
cuanensis) in deeper water has its borrowed
shell frequently surrounded by a bright orange
sponge (Suberites domuncula), with a strong
odour, a disagreeable taste, and countless flinty
needles — which fishes naturally leave alone !

A LIMB FOR A LIFE

Many different kinds of animals, especially
those with rather lanky limbs, practise a curious
kind of surrender — a limb for a life. And
what they surrender as a ransom for their life
they can regrow at leisure.

This is well illustrated by many star-fishes.
If an arm is pinned down by a stone, or seized
by an enemy, or if a sea-slug has settled on an
arm and cannot be dislodged, the star-fish
manages to break off the arm at the base.
In so doing it is behaving as we behave when
we draw back our finger from a very hot plate,
or shut our eye when a stone is about to strike
it, or cough when a crumb of bread threatens
to "go down the wrong way." We do not
think about doing any of these things nor
exercise our will ; what we do is called a reflex
action, carried out by means of pre-arranged

4

50 THE HAUNTS OF LIFE

linkages of nerve-cells and muscle-cells. So
is it in the star-fish when it surrenders an arm.
We know that the star-fish does not do this
deliberately, for it has a very poorly developed
nervous system. There is a strand of nerve-
cells up the middle line of the under surface of
each arm, and these are united in a pentagon
around the mouth ; there are also many
scattered nerve-cells ; but there is no brain,
not even a single nerve-centre or ganglion.
The star-fish does not know what it does, but
it has somehow in its constitution learned in
the course of time that it is better that one
member should perish than that the whole life
should be lost. Brittle-stars give off their
arms very readily ; sea-cucumbers are less polite,
for they discharge their insides in the spasms
of capture ; sea-urchins have nothing that they
can give away save their spines. We see the
same sort of surrender when the lizard gives
off its tail, and we find many cases among
insects and spiders. It is very marked in the
harvest-men, who stalk about in the evening
among the stubble, with legs over twenty times
the length of their body. The self-mutilation
("autotomy ") is also very common among
Crustaceans.

THE SCHOOL OF THE SHORE 51

A common accident on the seashore is that
a crab gets its leg badly broken by a moving
stone. When that happens the crab goes in
for surgery. By a very forcible contraction of
the muscles at the base of the damaged leg
the crab manages to break it off across a weak
line. And just below this breaking line there
is inside the base of the leg a two-flapped
membrane which closes up the wound and
prevents bleeding. Inside the bandage a new
leg is formed in miniature, and at the next
moult this shoots out like a Jack-in-the-box,
and soon hardens.

COLOUR CAMOUFLAGE

The common shore-crab (Carcinus mcenas)
occurs in many colours when it is young, and
these sometimes harmonise exactly with the
rock of the pool in which the particular crab
lives. But there is no change of colour except
after a moult. It is different with the Aesop
Prawn {Hippolyte varians] which takes on the
colour of its surroundings, both when young
and when adult, and can change from one
colour to another with ease. It has a large
repertory — red, yellow, blue, orange, olive,

52 THE HAUNTS OF LIFE

violet, brown, and green, and it is often
almost perfectly self- camouflaged among
brightly coloured seaweeds.

Not less subtle is the rapid change of
colouring and pattern in flat fishes like plaice
and dab. Very quickly they put on the hue
and the marking of the sand or shingle on
which they are resting. When on sand they
usually cover themselves quickly, all except the
eyes which protrude and look about. Blind
flat fishes do not change colour, so we know
that the message from the outside world first
affects the eye. It travels to the brain, and
by the nervous system to the colour-cells in
the skin which can change their size and
position. In some instances the change occurs
in a minute or two, and it gives the fish a
garment of invisibility.

In the aquarium at New York there is
often a startling display of coral-reef fishes
from the Bermudas and similar places. Their
colours are brilliant, and their patterns are
almost incredible. It seems to some natural-
ists quite impossible that these colours and
patterns can have concealing value, partly
because they are so conspicuous, one might
almost say daring, and partly because they

THE SCHOOL OF THE SHORE 53

differ so much in fishes from the same
reef.

So it has been suggested that they are
warning colours, useful in impressing enemies
with the fact that many of these brilliant fishes
are unpalatable and best left alone. And
another view is that coral - reef fishes are
so safe, with so many holes and corners to
play hide-and-seek in, that they can afford to
be any colour. On this view, the colours are
of no more use than the colours of withering
leaves.

On the other hand, Mr. W. H. Longley,
who has walked about on the floor of the coral
sea and watched the fishes for hours, maintains
that many of the most brilliantly coloured are
very well camouflaged when they are in the
particular kind of corner that they like best as
a home. Some have two kinds of coloured
pattern, suited for two haunts — a sort of Jekyll
and Hyde business. Some are longitudinally
striped or with no pattern when on the move
and cross-striped when they settle down. It
looks as if there was a great deal of useful
camouflaging.

54 THE HAUNTS OF LIFE

LOVE ON THE SHORE

The business of living creatures is two-fold
— caring for self and caring for others. Perhaps
we have said enough about caring for self on
the shore ; what about caring for others ? The
mother-seals nurse their young ones among the
rocks, and many birds, such as guillemots and
razor-bills, puffins and kittiwakes, make their
nests on the cliffs. When we see the narrow
ledges on which the guillemots and the razor-
bills lay their eggs — just one for each bird —
we wonder that there is any successful hatch-
ing at all. The wind searches every shelf, and
there is such a crowded coming and going of
mothers that the egg has every chance of
being jostled. But Darwin asked naturalists
to notice the pear-like shape of the egg and
the particular way in which it moves when it is
twirled in an eddy or jostled by the bird's feet.
Because of its shape it tends not to roll, but
simply to rotate on its short axis without
moving from its place. If we give it a vigor-
ous twirl on a smooth table, it simply rotates
without rolling. For this reason, then, it does
not fall off the narrow ledge into the sea.
This is a simple example of what is meant by

THE SCHOOL OF THE SHORE 55

a fitness or adaptation — some peculiarity of
structure or habit which is particularly well
suited for special conditions of life ; and one of
the pleasures of Natural History lies in the dis-
covery of these fitnesses.

The turtles come ashore from the warm seas
and lay their eggs in the sand, and the mothers
linger till their young ones are hatched. The
Edible Turtle is a vegetarian, living on sea-
weeds, and must therefore keep within the
shore-area in the wide sense. It has not far
to migrate when the time of egg-laying draws
near. But the fish-eating turtles of the Open
Sea, like the Hawksbill Turtle and the Snap-
ping Turtle, often make long journeys before
they find suitable places for egg -laying on the
shores of island or continent.

The venomous sea-snakes, well known in
the Indian Ocean, are tenants of the Open Sea,
but some of them at least come to the shores
at the breeding season. They do not lay eggs
as the turtles do, but bring forth their young
as fully formed little snakes, and it is interest-
ing to know that the mother often remains for
a while with her children, until they are able to
fend for themselves and follow her out to sea.
This is what we mean by "love" on the sea-

56 THE HAUNTS OF LIFE

shore, and however big we make the inverted
commas we cannot persuade ourselves that the
maternal care of the sea-snakes is not on the
same line as that of any human mother, vastly
finer as that usually is.

The quaint fish called the Lumpsucker or
Cock-Paidle (Cyclopterus lumpus] lays a big
bunch of reddish eggs in a corner of a deep
rock-pool low down on the shore, and over
this the father mounts guard, driving away
intruders. Every now and then he lashes
with his tail very vigorously beside the mass
of eggs, and this no doubt helps to aerate the
eggs and to scatter away the minute particles
of mud which might settle upon them. The
Lumpsucker has had its hind fins (pelvic fins)
shunted forwards and turned into a strong
muscular sucker, and he can grip a rock when
he is paddling vigorously with his tail. We
suppose the Scots name Cock-Paidle refers to
this paddling of the cock-fish. His paternal
duties occupy him for several weeks, and
observers say that while he is on guard he
neglects his own meals.

There are sticklebacks on the shore as well
as in fresh water, and the males make nests and
mount guard over them, but this story will

THE SCHOOL OF THE SHORE 57

keep till we come to the fresh-water haunt.
Less familiar is the case of a tropical shore-fish
(the Gaff Topsail), which has only a few eggs,
and lives in places where the struggle for exist-
ence is very keen. What is it to do? The
male fish takes the eggs in
his mouth and keeps them
there until they are hatched.
One would think it must be
difficult not to swallow them,
but he fasts all the time.

There are many other
examples of "love" on the
seashore. The marine leech
or Skate-sucker (Pontobdella
muricata), a warty green
animal, is both male and
female at once, like earth-

i .t f^ . FIG. 3. — THE SKATE-

worms and snails. It is a SUC£ER (PONTOB.

very careful parent, deposit-

, . . . , A Marine Leech that

ing the eggs in cocoons inside takes great care of itg

empty shells of bivalves, and
mounting guard over them for many weeks.
It is interesting to find examples of marked
parental care on the lower rungs of the ladder
of life. One of the humblest illustrations is to
be found in a British star-fish, Asterias mulleri^

58 THE HAUNTS OF LIFE

in which the fully formed young ones, skipping
the usual free-swimming stage in the open
water, are carried about on the mother's
body.

A pretty sight is sometimes seen if we watch
one of the common sand-hoppers (Gammarus
locusta], an Amphipod crustacean, flattened
from side to side, which is always busy clean-
ing up on the shore. If we have caught the
right kind and put it in a saucer we may see
quite a crowd of young ones emerging from
the shelter of the mother's body, just like
chickens from under a hen. They swim about
like miniatures of herself, and as she slowly
moves they follow, never venturing to go
farther than an inch away. If we make a little
splash in the water in the saucer, they hurry
back below their mother, just like chickens
again. Looking at this in a broad way,
through a mental telescope, we see that living
creatures always answer back to surrounding
difficulties and limitations, and that one of the
most effective ways of answering back is for
the parents to look well after the children.
But who wants " morals" at the end of
stories !

THE SCHOOL OF THE SHORE 59

THE STORY OF PALOLO

Every autumn, on the shore at Samoa, near
where Robert Louis Stevenson used to live,
there is what is called a swarm of Palolo.
Now Palolo is a green worm, whose proper
name is Eunice viridis, and its home is in the
crevices of the coral-reefs. In the fall of the
year the body of the worm becomes full of
germ-cells, — egg-cells in the female which
develop into young worms, and sperm-cells in
the male which fertilise the eggs. This is of
course the usual story with animals. Now in
October or November, at the third quarter of
the moon, for a short time after midnight, the
Palolo worms become very restless. They
back out of the holes among the corals and
writhe in the water. The whole of the body
breaks off a little way behind the head, and
the headless bodies are so numerous in the
water that it looks like vermicelli soup. The
headless bodies burst, liberating the germ-cells ;
some of the egg-cells are fertilised by some of
the sperm-cells, and a new generation begins.
The heads creep into the crevices of the coral-
reef and begin life afresh, growing a new body.
Thousands of the headless, wriggling bodies are

60 THE HAUNTS OF LIFE

washed on to the sand by the tides, and the
natives gather them in baskets to make a
Palolo feast. About the same time, just as if
they knew, the land-crabs come down to the
shore, and there is a Palolo feast for them
also. The regularity of the swarm is very
interesting — an inside change in the animal
keeping time with an outside change in the
seasons — and it should be noticed that there
are in other parts of the world other kinds of
Palolo worms which " swarm " at a different
time of year. The association with the moon
is curious and so is the concentration to a short
time after midnight. The wriggling of the
headless bodies in the water is another very
interesting point. But we get furthest into
the heart of the queer story when we notice
that whereas many worms (and other animals,
like butterflies, lampreys, and eels) die in
giving rise to new lives, the Palolo-worms
evade this penalty. They surrender the
greater part of their body, but the heads
creep back into the coral reefs and begin
again.

THE SCHOOL OF THE SHORE 61

A GREAT SCHOOL

For a long time after the earth became a
home of life there were no animals on land at all.
As far as we can judge it was in the sea that
the first living creatures lived — either in the
open sea or on the shore. Whether the shore
was the first haunt of life or the second it is
difficult to say, but it is likely that most of the
great races of animals sojourned for a long
time on the shore and, as it were, served their
apprenticeship there. Now on the shore there
are, as we have seen, many spurs to adventure
and many outside changes that provoke changes
in the structure and constitution of the animals.
The shore is a haunt where animals are
prompted to play all their cards, to make
experiments with all their possibilities, just as
we ourselves do when we are in a tight place.
The shore animals test all things and hold fast
that which is good. Or, to look at it from
another side, the shore has always been a place
of sifting, where those creatures that were not
fit to cope with the changeful, difficult, crowded
conditions have been rejected. It is in this
sense that we may speak of animals learning
lessons on the seashore : not learning lessons

62 THE HAUNTS OF LIFE

as we do, by getting ideas into our head, but
rather as the races of domestic dogs or horses
have in the course of thousands of years
learned lessons. Inborn qualities that were
unsuitable have brought penalties to their
possessors, and these have been wiped out from
the list of shore animals. Inborn qualities that
were peculiarly well fitted for shore-conditions
have brought their possessors great success,
and these possessors have survived.

When useful qualities are established in a
race of animals, like docility in dogs, they are
not readily lost. They may be lost along
certain lines of descent, just as pigment has
been lost in white rats which are descendants
of the common brown rat, but they are not
likely to be lost altogether. So it is not
fanciful to suppose that qualities, which were
established among shore animals millions of
years ago, may have enriched the inheritance of
animals which are now far away from the shore,
may even have enriched Man's inheritance.
Those in the highest form of a school may not
remember that they learned anything when
they were in the junioc school, though they
probably learned much !

But what were the good qualities which the

THE SCHOOL OF THE SHORE 63

ancestors of the great races of animals may
have had engrained in them when they lived
very long ago on the shore? They included
the quality of holding tight, which leads on to
endurance, the quality of biding their time —
even till the tide comes in — which leads on to
patience, the quality of push, which leads on to
endeavour, and the quality of seizing a good
opportunity, which leads on to alertness and
power of initiative. These are some of the
great lessons of the old school of the shore.

CHAPTER II
THE OPEN SEA

Contrast between Shore and Open Sea — The Floating Sea-
Meadows — The Animals of the Open Sea — Sea-Deserts —
Swimmers and Drifters — The Whale as a Great Bundle
of Fitnesses— The Story of the Storm Petrel— Open- Sea
Insects — Turtles — Sea-Snakes and Sea-Serpents — Fit-
nesses of Open-Sea Drifters — The Story of the Floating
Barnacle — Hunger and Love in the Open Sea — The Open
Sea as a Nursery.

BY the open sea, naturalists mean the well-
lighted surface-waters well away from
the shallow shelf around the islands and conti-
nents. It is not the mere surface of the water,
it includes all the zones of water through which
the light penetrates freely ; and that, we must
remember, is much farther than at the coast
where the waves stir up the sea-floor and bring
so many fine particles into suspension in the
water, that much of the light is stopped. In
the upper levels of the open sea or pelagic
haunt, there are multitudinous minute plants

mingled with the animal tenants ; deeper down

64

*40

PLATE III. — FOUR OPEN-SEA ANIMALS.

The Portuguese Man of War, on the surface, with its cockscomb-like red
float ; the mother Argonaut or Paper Nautilus with its cradle-shell, made
by and embraced by two of the arms ; two Jelly-fishes below the surface ;.
and a carnivorous Turtle pursuing a fish.

THE OPEN SEA 65

where the light is less abundant there are more
animals than plants ; deeper still there are
animals only.

If the shore area is the Great School of life,
where animals have learned and are still learn-
ing many lessons, the open sea may be looked
on as the cradle of life. There are many
authorities who believe that it was there that
life had its beginnings, far back in the dim past.
" There can be little doubt," writes one, "that
the pelagic fauna antedated all the faunas of
the globe, and that from it, through a long
process of modification and adaptation, have
been derived the faunas of the shore, the
abyssal depths, the land surface, and the fresh
waters."

But this question of beginnings is too
difficult for us ; we must content ourselves with
taking the "pelagic fauna," which means simply
the animals of the surface of the sea, as we
find it now. But even now we are justified in
speaking or the open sea as the cradle of life,
for many of the animals which, in their adult
state, live amid the turmoil and struggle of the
shore, spend their delicate youth in the easier
conditions of the open sea. The eggs and
larvae of some fishes, too, whose home is on
5

66 THE HAUNTS OF LIFE

or near the floor of the sea, are found floating
at or near the surface.

CONTRAST BETWEEN SHORE AND
OPEN SEA

The shore waters pass gradually into the
open sea, and the surface zones pass gradually
into the dark, deep-water zones, but the haunt
which we call the open sea has well-marked
characters of its own. It is a place of spacious-
ness, freedom, and plenty. Let us contrast it
with the shore haunt. There are three great
differences, (i) The seashore is crowded, the
open sea is spacious ; there is room and to
spare for all. (2) The shore is very change-
ful, the open sea is much more uniform. The
differences between morning and noon, day and
night, summer and winter, are less marked in
the open sea than on the shore. The open sea
is not indeed a place of rest, for the pelagic
animals swim or drift unceasingly, and " know
no rest from birth till death." But even this
movement often makes things easier, for many
of them can sink or rise in the water, getting
out of the glare or the heat, or coming up to
where oxygen is most abundant. (3) On the

THE OPEN SEA 67

shore there is abundant food, but there is a keen
competition for it, and there is a tendency for
many of the nourishing particles in the water
to slip past and to sink down the inclined plane
to the deep waters. But in the open sea there
is in most places great abundance of food, and
it is accessible to all. So there are three great
reasons why pelagic life is easier than littoral
life.

It may be objected that the open sea is the
place of storms, and it is true that there are
terrible days when sea and sky seem to meet in
a welter of tumultuous water. But storms are
more dangerous near shore than in the open
sea when there is nothing to knock against, and
few of them have a deep grip. Many of the very
delicate open-sea animals, like the iridescent
and luminescent comb-bearers (Ctenophores)
sink into quiet water whenever there is a hint
of white-horses. So, in spite of storms, we may
say that in the open sea the barque of life sails
on an even keel. One of the disastrous effects
of storms is seen where one would not at first
look for it, namely, among some of the open-sea
birds, like gannets. The fishes and other
creatures on which they feed have taken to
deeper levels in the water, which only the deep-

68 THE HAUNTS OF LIFE

divers can reach, and if the storm lasts for
several days the gannets and similar sea-fowl
begin to starve. They become weak, and they
get battered. Perhaps this is part of the
explanation of the fact that the gannet often
stores fish beside its resting-place on the
rocky island.

THE FLOATING SEA-MEADOWS

If we are to understand the life of the open
sea at all, we must picture what Sir John
Murray called the " floating sea-meadows," —
vast tracts of water thickly peopled by minute
plants, e.g. those Algae called Diatoms. On
these everything else depends. For the pelagic
Algae are possessed of the chlorophyll pigment
that marks all green plants, and they are thus
able to utilise the energy of the sunlight to
build up the simple materials of air, water, and
salts into complicated substances like starch, on
which minute animals can feed. Of almost all
animals it must be said that they can feed only
on what is living, or has been living, or has
been made by something living ; but green
plants feed on what is not living — air, water,
and salts. Therefore, in tracing the circulation

THE OPEN SEA 69

of matter, we must always begin with the
plants.

In most parts of the sea, wherever the sun-
light penetrates and the temperature is not too
low, there are countless myriads of simple
plants, " scattered like dust amid the immeasur-
able water masses." These minute marine
Algae are not visible to the naked eye, and it
is only within comparatively recent times that
their abundance, and their great importance in
the chain of life in the ocean, have been fully
recognised. Between Australia and New Zea-
land, we are told, the officers of the Challenger^
the ship of the great ocean expedition sent out
by the British Government in 1873-1876,
found the water "continuously discoloured
during a period of several days' sailing, and
giving off the odour of a reedy pond." Else-
where too, even in the Arctic Regions, the
water is sometimes "as thick as soup."

Along with the minute Algae there are many
minute animals (Infusorians) which have got
possession of the green pigment chlorophyll,
and there are others (Radiolarians) which have
Algae living in partnership with them. All
these form part of the fundamental food-supply
of the open sea. They are eaten by minute

70 THE HAUNTS OF LIFE

animals, such as the small crustaceans called
water-fleas, and these may be eaten by fishes.
The bodies of dead animals are broken down
by microbes, and what is not devoured by other
animals passes in solution into the sea-water
and may be absorbed again as part of the food
of Algae. The same is true of the waste-pro-
ducts voided from the food-canal and kidneys
of animals. Nothing is ever lost ; all things
flow.

The naturalists at the Plymouth Biological
Station have shown that the abundance of
mackerel in the spring months depends on the
abundance of the minute " water-fleas " or cope-
pods in the upper waters, and this again depends
upon the abundance of minute Algae called
Diatoms and of minute animals called Peridinid
Infusorians, which form a great part of the
" stock " of the sea-soup. As the multiplication
of the Diatoms and Infusorians in the surface
waters depends mainly on the amount of sun-
light in the early part of the year, we can see a
connection between the sunniness of the spring
and the supply of mackerel at Billingsgate.
The whole world is run on a plan of successive
re-incarnations. Diatom or Infusorian, first link ;
copepod or water-flea, second link ; mackerel,

THE OPEN SEA 71

third link ; man, fourth link ; and so the world
goes round.

This nutritive chain is interesting in theory,
but it is also very important practically, for on
the abundance of the floating sea-meadows, and
the population of small animals which these
support, there depends, in large measure, the
success of the fishing industry in northern
seas.

In addition to the microscopic plants there
are in some places great masses of drifting sea-
weeds of a higher order. They sometimes
occur in such enormous dense patches that they
impede the progress of ships passing through
them. These seaweeds do not grow at the
surface but on the sea-floor in the shallow water
region, and when they are torn off by the waves
they are carried by currents far out to sea.
They live for a considerable time floating
at the surface with the aid of their numerous
little bladders, but gradually they lose their
vitality and finally sink slowly to the bottom.
New clumps are continually being brought by
the same currents, so that in some parts of the
ocean seaweed is always present. The best
known of these areas is the Sargasso Sea in the
Atlantic, and the weed there harbours count-

72 THE HAUNTS OF LIFE

less animals of many kinds, which play hide-
and-seek among the fronds.

It is interesting to learn that the animals that
live in the Sargasso Sea, instead of being pre-
dominantly blue and grey, are clothed in reds,
browns, and dull greens, like the weed among
which they hide, and they have these colours
even when their relatives in the open sea are
blue. Some of them have the body reddish-
brown, but the fins, which have to be spread
out in the open water, are blue. It is thought
that the amount and intensity of light have a
great deal to do with developing the different
colours of animals at different levels of the
ocean, but, whatever be the cause of them,
there can be no doubt that their effect is often
to secure greater safety for their possessors.

THE ANIMALS OF THE OPEN SEA

Can we call the roll for the Open Sea?
There are many different kinds of Infusorians,
among which there is the world-wide giant,
Noctiluca or Night- Light, which makes the
waves sparkle in the summer darkness. A
giant indeed, for it is about the size of a pin-
head. Many of the chalk-forming animals or

THE OPEN SEA 73

Foraminifers float in the surface-waters, and
this is true of most of the very beautiful Radio-
larians, which have usually shells of flint, and
have established an internal partnership with
microscopic Algae. Perhaps it is this partner-
ship that has made them so successful, for there
are 5000 different kinds, and the number of
individuals is past all telling.

The Stinging Animals are represented by
swimming-bells, most of which are budded off
from shallow-water zoophytes ; by true jelly-
fishes or Medusae, rhythmically contracting and
expanding their translucent discs ; by strange
colonies like the Portuguese- Man-of- War ; and
by the delicate Ctenophores. One of these
called Venus's girdle^ like a ribbon of flexible
glass, iridescent and phosphorescent, is one of
the most beautiful animals of the sea.

There are not a few open-sea worms, some
of them, like the Arrow-worm, quite trans-
parent ; and there are actually a few sea-
cucumbers which have departed widely from the
sluggish habit of their shallow-water and deep-
water relatives.

Jointed-footed Animals are represented by
many kinds of Crustaceans, from gorgeous
prawns to pinhead-like "water-fleas"; and

74 THE HAUNTS OF LIFE

one must not forget the family of Open-Sea
Insects,

Molluscs are represented by the Sea-Butter-
flies and other lightly built translucent Gastero-
pods, and by a number of active cuttlefishes,
such as the Argonaut and some squids.

Just across the border-line separating the
backboned from the backboneless animals is
the class of sea-squirts or Tunicates, and it is
interesting to find a few of these in the Open
Sea which do not degenerate as their shore-
relatives do, but keep up the promise of their
youth. Others form free-swimming colonies
like the brilliantly luminescent Fire-Flame,
sometimes as long as one's arm, and with a light
that one can read a few words by. Highly
fitted for open-sea life are the Salps, sometimes
like single barrels of glass, two or three inches
long, sometimes in long chains, which swim
gently like glass-serpents in the sea.

The rest of the roll is easy, — the open-sea
fishes like the flying gurnard, some turtles and
sea-snakes, some birds like petrels and penguins,
and then the whales among Mammals. 1 1 is evi-
dent that the Open Sea has its share of variety.

THE OPEN SEA 75

SEA-DESERTS

Some parts of the Open Sea have only a
sparse floating population compared with others.
Mostof the Mediterranean is poor when compared
with the North Sea. To the west of Patagonia
in the South Pacific there is what may be called
a sea-desert : there are few fishes and few sea-
birds ; there are almost no floating sea-meadows.
On the floor of the sea in that region there is
an unusual profusion of sharks' teeth and the
ear-bones of whales, which has given rise to the
suggestion that these huge creatures get into
the sea-desert and die of hunger before they
find their way out. The teeth and ear-bones
are so hard that they can scarcely be dissolved
in the sea ; they accumulate on the floor as
relics of ill-fated visitors to the desert.

SWIMMERS AND DRIFTERS

The animals of the open sea are divided into
(i) the active swimmers (technically making up
the NEKTON) ; and (2) the drifters, or easy-
going swimmers (technically making up the
PLANKTON). Good examples of the energetic
swimmers are the whales, both great and small,

76 THE HAUNTS OF LIFE

the petrels,- the sea-snakes, the herring and
mackerel, the flying-fishes, the squids, and
some of the prawn-like crustaceans. The
drifters may be illustrated by the sea-butterflies
(delicately built sea-slugs on which whalebone
whales largely feed), hundreds of kinds of
small crustaceans, numerous worms like the
transparent arrow called Sagitta, complicated
colonies like the Portuguese Man-of-War, and
the sail-bearers (Velella), often seen in the
Mediterranean in beautiful fleets stretching for
miles. More familiar are the jelly-fishes, often
borne into shallow water and left stranded in
thousands on the beach.

These two sets of animals, the swimmers
and the drifters, are so different that it is better
to study them separately. They represent, so
to speak, two different attitudes to life. One
remembers George Meredith's lines :

" Behold the life of ease, it drifts ;
The sharpened life commands its course.
She winnows, winnows roughly, sifts
To dip her chosen in her source.

Contention is the vital force

Whence pluck they brains, her prize of gifts."

To keep our ideas clear we must understand
that animals may be tenants of the open sea

THE OPEN SEA 77

for part of their life and at home elsewhere
at another period. Thus the guillemots and
puffins, which nest in early summer in such
vast numbers on some of the British bird-cliffs,
are open-sea birds for a considerable part of
the year. Many shore animals, such as crab
and rock-lobster, star-fish and sea-urchin, have
free-swimming larvse in the open water, often
many miles from the coast. Jelly-fishes are
characteristically open-sea animals, their strand-
ing on flat beaches being quite accidental, but
it should be noticed that the common and
cosmopolitan jelly-fish, Aurelia aurita, passes
through a juvenile fixed stage, attached to rock
or seaweed.

THE WHALE AS A GREAT BUNDLE
OF FITNESSES

The mammals of the open sea are the
Cetaceans, giants like the Right Whale and the
Sperm Whale, and small ones like dolphins and
porpoises. All of them have such mastery of
their medium that they must be ranked among
the conquerors of the open sea. Let us think
for a little of the whale as a great bundle of
fitnesses, taking especially the Greenland or

Bi

8«

tf

*8

*•§

. isJ

2 «

Cfi-

THE OPEN SEA 79

"right" whale, right from the whaler's point of
view.

The whale is fish-like in shape ; it has fore-
fins like a fish, and it swims by means of its
powerful fish-like tail. Yet, though we talk of
whale " fishery," we all know that a whale is
not a fish but a mammal, that is, a warm-
blooded animal that breathes by lungs, and
gives suck to its young. Naturalists have been
able to show, from a study of the whale's own
body and the bodies of its fossil relatives, that
the ancestors of the whale were land mammals,
and that, in taking to the sea, they lost many
of the old characters of their race and acquired
others more suited to their new mode of life.

The body is now fish-like because that is
the shape most suitable for cleaving the water ;
the fore-limbs are flippers or paddles, yet within
them " the whole inherited but greatly shortened
skeleton of the mammalian forearm lies con-
cealed." The hind-limbs were no longer of
use, so they disappeared, but traces of their
bones can still be found hidden beneath the
blubber ; the skin has lost its hair, except for
a few very sensitive vibrissae or whiskers about
the mouth, but indications of hair can be seen
in the developing young ; and under the skin

8o THE HAUNTS OF LIFE

there is a thick layer of fat or blubber, which
serves the double purpose of keeping the body
warm and lightening its weight in proportion
to its size.

The whale catches the minute animals on
which it feeds by swimming with its mouth
open. But it must be able to breathe atmo-
spheric air, not air dissolved in water as a fish
does, and the nostrils, instead of being on the
snout as in other mammals, are far back on the
forehead, so that breathing can go on at
the same time as swallowing. In short, as
someone has said, if you took away from the
whale all that is adaptation to its mode of life
there would be very little of it left.

The teeth, when there are any, have changed
in character, but in the "right" whale they
disappear before birth, and have been replaced
by long horny plates frayed at the ends, which
hang down into the mouth. There are from
three to four hundred of these plates, which
form the valuable "whalebone" of com-
merce. The whale swims with open mouth
through shoals of small animals like the sea-
butterflies and water-fleas we have spoken of,
and when it has secured a good mouthful it
shuts its jaws and lets the water trickle out at

THE OPEN SEA 81

the sides of its mouth, while the whalebone
plates act as a sieve and prevent the small
animals from getting away. The stomach of
a dead whale has been found to contain a mass
of minute animals so thick that it could only be
dug out with a spade.

The whale has no settled place of abode in
the ocean, and its swimming powers enable it
to make enormous journeys. Some whales
" travel twice a year more than a quarter of the
circumference of the globe, being in summer
amid the Arctic snows, and in winter on the
other side of the equator." They travel mainly
in the wake of their food-supply, but as there
is a great regularity in the occurrence of the
smaller marine organisms, " their journeyings
are in general as regular as if they were
arranged according to the stars, and as if they
took place along laid-out paths bounded on
both sides."

On their journeyings the whales often form
troops or " schools," consisting chiefly of females
and young ones. The Greenland whale has
usually only one young one at a time, which
may be over three yards long at birth. The
mother gives it suck for about a year, and is

devotedly attached to it.
6

82 THE HAUNTS OF LIFE

Unfortunately for the whale man long ago
discovered the value to himself of the whale-
bone and the blubber, and the chase of the
"right" whale has gone on for centuries.
Even its mother-love has been turned to its
disadvantage, for the inexperienced young one
is easily caught, and the mother is absolutely
careless of her own safety in her efforts to
protect her offspring. Modern improvements
in fishing vessels and apparatus have made the
warfare a very unequal one, and this interesting
animal is fast disappearing from the seas.

THE STORY OF THE STORM PETREL

No creature is more characteristic of the
Open Sea than the Storm Petrel, for it rarely
touches land except at the nesting-time. From
the breeding-places, such as islets to the north
and north-west of Scotland, they migrate in
autumn to open waters and spend all the winter
there. One of their many names, Mother
Carey's Chickens, suggests that they are dear
to the Holy Mother, who has the weak and
storm-tossed in her keeping. As to the word
petrel, it is supposed to refer to St. Peter's
attempt to walk on the water, but it is more

THE OPEN SEA 83

likely that it points to the way in which the
birds' feet go pitter-pattering as they touch the
waves in their flight.

The Storm Petrel is a sooty-black bird, with
a little white about the tail and under the wings,
just over six inches in length, with long, some-
what swift-like wings well-suited for rapid flight,
and with long legs, the meaning of which is
obscure. Its relationships are with albatross,
shearwater, fulmar, and the like, and in nowise
with the gulls. This is shown by the fact that
the horny bill is made up of numerous pieces
(taking our thoughts back to reptiles' scales),
by the curious drawing out of the two nostrils
into a double - barrelled tube, by the single
chalky-white egg with a few reddish-brown
spots, by the very long sooty-ash down covering
the nestling, and by many features going much
deeper.

The Storm Petrel flies close to the waves
with its web-feet touching now and then, and
at other times it paddles about on the surface.
Its food consists of small fishes, crustaceans,
molluscs, and other Open-Sea animals. At the
nesting-time it seems to be fond of morsels of
sorrel ! The crop contains a good deal of oil
which the bird vomits up forcibly when taken

84 THE HAUNTS OF LIFE

by surprise. It is given by both parents to the
young. A captive Storm Petrel was fed for
three months on oil alone. The amount of oil
throughout the whole bird may be inferred from
the fact that some islanders thread a wick
through the dead body and use it as a lamp,
"the excess of fat burning steadily until the
whole is consumed."

The Storm Petrel's nest hardly deserves the
name ; it is never more than a little mattress of
dry grass. The single egg is laid (about the
end of June in Scotland) in a hole among the
rocks or among loose stones, or in a burrow,
which may be a rabbit's, or may be partly made
by the bird's own exertions, though one would
not think that tunnelling was much in its line.
There is a heavy musky smell about the hole.

The parents seem to share in brooding,
which lasts for about five weeks. During that
time the birds are not seen coming or going,
for they have become twilight birds, or dawn
and dusk birds. We suppose one parent sits
by day and the other by night. After the
young bird is hatched out, it seems to be left
to itself all the day long, while the parents
collect oil for the heavy supper which their
nestling makes and needs. It is not till the

g

8

in

I

THE OPEN SEA 85

autumn that the young bird is able to leave the
hole and fend for itself, — a very prolonged
infancy which shows us that the nesting-place
must be well hidden. In this connection it
should be noted that the parents fly straight
into the hole when they come in from the sea
and leave in the same direct way. They are
sometimes quite noisy as they fly about at
night, but they know the safety of darkness.
They come and they go in dim light, at dusk
and at dawn. Most elusive birds !

There is no doubt that the Storm Petrel
belongs to a family of ancient birds, with a long
pedigree going far back to some kinship with
an extinct, giant, toothed Diver (Hesperornis
of Cretaceous times). Like its relatives, such
as the shearwaters, it has held its own by
becoming highly specialised in its everyday
habitat and also in its way of feeding on small
surface animals of the Open Sea. It is very
interesting to find among its relatives a Diving
Petrel (Pelecanoides), remarkably but decep-
tively like a Little Auk, which has become a
most expert diver, disappearing instantaneously,
swimming swiftly with its wings under water,
and emerging again in flight — a brilliant
instance of the way in which survival is secured

86 THE HAUNTS OF LIFE

by trying every niche of opportunity. It is the
same with the Storm Petrel ; it has survived
by its originality.

OPEN-SEA INSECTS

A fine example of what we may call the
adventurousness or insurgence of life is to be

FIG. 5. — SEA-SKIMMER, HALOBATES.
An Insect that runs about on the Open Sea.

found in the family of sea-skimmers (Halo-
batidse), wingless insects that run along the
surface of the water, often a hundred .miles
from land. They are closely related to the

THE OPEN SEA 87

water - measurers (Hydrometridae) which we
see skating about on the surface of stagnant
pools or even on quiet reaches of a stream,
but if we had been asked for the unlikeliest
haunt for an insect we should surely have said
the open sea or the deep sea. The sea-
skimmers appear to feed on floating dead
animals, and when it is stormy they sink
below the troubled waters — how, we do not
know. Another interesting point is that the
mother sea-skimmer has been seen carrying
her eggs about with her after they have been
laid.

TURTLES

Among the higher animals of the open sea
must be reckoned some of the turtles ; not the
edible turtle, perhaps, for it is a vegetarian,
and must, therefore, keep for the most part to
the shore haunt, where seaweeds grow, but the
carnivorous Hawksbill and the Loggerhead —
the latter occasionally found on British coasts.
There is also the rare Leathery or Lyre Turtle
of most warm seas, a veritable pelagic giant.
Dr. F. A. Lucas, Director of the American
Museum of Natural History, tells us that he

88 THE HAUNTS OF LIFE

has weighed some up to 940 Ib. and measured
some up to 7 feet in length. All these are
doubtless the descendants of land tortoises,
for they breathe dry air as terrestrial animals
do, and they give away their secret in the fact
that they all come to the shore to lay their
eggs in the sand. Animals that have found a
new kind of home usually go back to the old
home to breed. Whales evade this law
because the mother carries her young one for
a long time before birth, so that when it is
born it can swim for itself.

SEA-SNAKES AND SEA-SERPENTS

Turtles have their legs flattened into flippers,
— the oars by which they swim ; whales have
their fore-limbs flattened into flippers, which
are chiefly used in balancing, the propeller
being the tail ; snakes have no limbs, but it
is interesting to find that the sea-snakes show
a marked flattening in the tail region, and
sometimes in the posterior part of the trunk
as well. In all cases the meaning of the
flattening is the same ; it is an adaptation
which secures a good grip of the water. The
sea-snakes are mostly fish-eaters, and very

THE OPEN SEA 89

poisonous ; they are common in the Indian
Ocean ; they are of course the descendants
of land-snakes, and, as we have already
mentioned, some of them least come to the
shore to bring forth their young.

The rock-record shows that there were once
great sea-serpents, and he is a bold man who
says he is sure there are none living to-day.
We remember seeing in the Prince of Monaco's
collection a great piece of a scaly cuttlefish.
It came from the stomach of a sperm-whale,
but no one has seen the animal. Unless the
piece was a piece of the very last scaly
cuttlefish, the animal is likely to be still
represented in the seas. Perhaps there may
be a giant sea-serpent too.

So many of those who go down to the sea
in ships have seen sea-serpents that it is quite
a reasonable inquiry to ask what kinds of sea-
serpents they saw. One species certainly
consists of the backs of a row of porpoises
swimming quickly and showing at regular
intervals on the surface. Another species
consists of a long single-file of sea-fowl flying
close to the surface. Another species is one
of the large sharks, another is certainly a large
cuttle, and another consists of the long lips

90 THE HAUNTS OF LIFE

and tentacles of a huge jelly-fish swaying near
the surface. Some jelly-fish have a disc a yard
in diameter, and tentacles over 30 feet in
length.

Another sea-serpent which our friend Mr.
James Reid of Stonehaven went far to identify
is almost certainly the Oar-fish or Ribbon-fish
(Regalecus), a silvery fish flattened like an oar,
sometimes over 20 feet in length. It is
normally a deep-water fish, but it sometimes
swims with an undulatory motion at the surface,
and may, when attacked by some enemy, raise
part of its body several feet out of the water.

FITNESSES OF THE OPEN-SEA DRIFTERS

It is plain that one of the chief requirements
of an animal that lives in the open sea is,
that it should be able to keep afloat. This is
secured in many different ways. Thus there
are various arrangements for increasing the
surface of the body without greatly increasing
the weight. Many minute surface creatures
are practically unsinkable even though their
skeleton is often made of flint. Their armature
is produced into delicate processes or, in some
cases, stalked discs like half dumb-bells, which

THE OPEN SEA

FIG. 6. — A REPRESENTATIVE JELLY-FISH OF THE OPEN SEA.
Note the four frilled Lips and the Tentacles round the Margin of the Disc.

92 THE HAUNTS OF LIFE

give them a big hold of the water. Some
larval fishes, like those of the Angler, have
long flexible ribbons floating out like decora-
tions ; and these probably help in flotation

(Fig. 7).

Some of the drifters have bodies large in
size, but with so much sea-water in them that
they cannot sink. They have almost the same
specific gravity as the water. If we look into
the sea from a boat we often see the common
jelly-fish (Aurelia) opening and shutting its
umbrella or disc a little below the surface.
It looks quite large in the water, and for a
time after it has been cast upon the shore
by the tide. But a few hours later it has
shrivelled up into a very papery heap indeed.
Its body is made up of more than ninety per
cent, of water, and when that has evaporated
there is very little animal matter left. A
great many drifting animals have this swollen,
watery tissue.

The presence of fat or oil serves the same
purpose of lessening the body weight, and
many of the smaller animals and some pelagic
eggs have this character in common with the
actively moving animals like the whales,
porpoises, and many fishes.

THE OPEN SEA 93 J

94 THE HAUNTS OF LIFE

Some of the drifters, instead of having the
whole body made light, have some special
part of it adapted to serve the same end. We
can best understand these adaptations if we
compare a pelagic animal with one of its own
relatives which lives under different conditions.
For instance, in many parts of the ocean, there
are often to be seen swarms of what are
popularly called "sea-butterflies," or, not quite
so prettily but more accurately, " winged
snails." These little animals are Gasteropod
Molluscs, and some of them — for there are
many different kinds — have shells, in one
case spirally twisted like that of the snail.
But whatever be the form of the shell it is
always small and light so as not to add much
weight to the body. In place of the fleshy
walking "foot" of so many land and shore
snails the sea-butterflies have "wings," not
in the least like those of a butterfly, but simply
outstretched lobes or leaves of muscle which
buoy them up and catch the wind so that
they seem to be skimming lightly over the
surface of the water. Most of the sea-
butterflies inhabit warm latitudes, but one
kind, with a shell no larger than a pin-
head, occurs in such numbers in the Arctic

THE OPEN SEA

95

seas that the fishermen call it " whale-
food."

Sometimes the special device for keeping
afloat is just some transformation of, or addition
to, the animal's usual organs of locomotion.
Many of the tiny crustaceans, known as
copepods or " water-fleas," have on the jointed
legs that they possess, in common with their
larger relatives — lobsters, shrimps, and the
like — thin projecting spines, each bearing
smaller spines, all so delicate and so much

FIG. 8.— AN OPEN-SEA "WATER FLEA."
Showing Delicate Processes which make Flotation easy.

interlaced that the whole structure has the
appearance of a feather. But that is not
enough to keep the copepod afloat ; it uses
the long antennae or feelers on its head to give
a kind of rowing stroke. It does this for

96 THE HAUNTS OF LIFE

several successive strokes, and then stops for
a little. " During the period of rest the body
sinks slowly, sometimes imperceptibly, but
never so much that it cannot recover its
position in the water after the first few
strokes."

THE STORY OF THE FLOATING BARNACLE

Barnacles are strange crustaceans which
give up free-swimming when they are very
young and attach themselves to drifting logs
or the keels of ships. Even a sea-snake has
been seen with a big bunch on its tail, and
some of the unstalked acorn-shells, which are
second cousins of the stalked barnacles, are
found attached to the skin of whales.

The newly hatched barnacle is like the
newly hatched larva of many of the lower
crustaceans. It has a body a little like half a
pear cut lengthwise and about the size of a
small pinhead. It has a median eye on the
top of its head and three pairs of swimming
appendages. It is called a Nauplius, but that
is neither here nor there. It feeds and grows
and moults, changing its form into what is
called a Cyprid larva. This seems to become

THE OPEN SEA 97

exhausted, for it attaches itself by its head to
a floating log, and the front of the head grows

FIG. 9. — A CLUSTER OF BARNACLES (LEPAS ANATIFERA).

Hanging from a Floating Log. Note the Curled Feet projecting from

the 5-valved Shell.

into a long elastic stalk, which bears the main
part of the body on its free end. From

7

98

THE HAUNTS OF LIFE

between the five valves of a shell that protects
the main body of the barnacle, six pairs of
feather-like limbs can be protruded, which
waft microscopic organisms and particles into
the mouth. So much for the ordinary ship-

A B

FIG. 10.

A. THE FLOATING BARNACLE, with a self-
made Buoy on the Stalk between it and a
piece of Floating Seaweed.

B. A COMMON BARNACLE.

barnacle, hundreds of which may sometimes
be found attached to a log which is tossed up
on the beach by a storm after having drifted,
it may be, across the Atlantic.

The particular kind of barnacle which we

THE OPEN SEA 99

are calling the Floating Barnacle (Lepas
fascicularis] often fastens itself to a small piece
of detached seaweed — it may be to a feather
or a wooden match. Its shell-valves are very
lightly built, with little lime in them, and this
is well suited for a creature that fixes itself to
a light float. But in spite of its lightness of
shell, the Floating Barnacle often becomes, as
it grows bigger, too heavy for its float, and
begins to drag it below the surface. What
then does the creature do — we wish we
understood it better — but make a somewhat
gelatinous, roundish buoy containing bubbles
of gas. This is secreted at the lower end of
the attaching stalk, just above the main body,
and the self-made buoy enables the barnacle
to continue floating at the surface. This is a
very pretty adaptation (Fig. 10).

HUNGER AND LOVE IN THE OPEN SEA

Hunger is much in evidence in the open sea.
The baleen whale rushes through the water,
engulfing countless open-sea creatures in the
huge cavern of its mouth. They are caught
on the frayed edges of the whalebone plates
which hang downwards from the palate. If

ioo THE HAUNTS OF LIFE

we look into the mouth of a good-natured
horse when it yawns we see ridges crossing
the palate ; if these ridges were to grow into
long vertical plates and become horny they
would correspond to whalebone plates. Every
now and then the whale raises its tongue and
brushes a myriad of creatures towards the
back of the mouth, where they are swallowed.
It is interesting that this giant should feed on
such dainty morsels. The reason why it does
not drown as it rushes open-mouthed through
the water is that it shunts its glottis (the
entrance to the windpipe) forward to embrace
the posterior end of the nasal passage, so that
no water goes down the wrong way !

But there is love as well as hunger in the
open sea, and no better example could be found
than the Paper Nautilus or Argonaut. This is
a kind of cuttlefish which floats on the surface,
and is not to be confused with the Pearly
Nautilus which belongs rather to the shore
haunt. The most remarkable thing about the
Argonaut is that the female makes, for the pro-
tection of its eggs and young ones, what may
well be called the most beautiful cradle in the
world. It is not a house to live in like the
chambered shell of the Pearly Nautilus ; it is a

THE OPEN SEA 101

cradle made by the female only. Moreover,
the delicate cradle is made as a secretion from
two of the "arms," not as a secretion from the
"mantle," the fold of skin which manufactures
the shell of all other Molluscs.

Another pretty case is the egg-raft of the
mollusc called lanthina. This open-sea Gas-
teropod has a lightly built shell of a fine violet
colour, and when the time for egg-laying comes
a bubbly float is made in which the eggs are
embedded, and this is towed about by the
parent as it swims.

THE OPEN SEA AS A NURSERY

Another big fact must be included in our
picture of the open sea — that it is the nursery
for the young stages of many shore-animals.
Delicate young stages which could not survive
for an hour in the rough-and-tumble conditions
of the shore are nurtured safely in the spacious-
ness and easy-going uniformity of the open sea.
There is no better example than the common
Shore- Crab (Carcinus mcenas). The develop-
ing eggs are carried about by the mother under
the shelter of her tail. Out of the eggs come
dainty pinhead-like, free-swimming larvae, called

102 THE HAUNTS OF LIFE

zoese, marked by a spine rising vertically above
the back, and by a tail sticking out at an
angle to the rest of the body. These larvae are
swept out into the safety of the open water, and
they swim about near the surface. They feed,
they grow, they moult, and another form of
larva results. This does the same, and a
Megalops larva results, which is beginning to
be like a crab. It has lost the spine; it has
stalked eyes; it has got its full complement
of legs. Now this Megalops bends its tail
forwards and upwards underneath the anterior
part of the body (the cephalothorax] ; it
ceases to be a free-swimmer ; it sinks to the
floor of the sea, and creeps up the slope
to its birthplace on the shore — a little crab
about half the size of the nail of our little
finger.

There is an interesting illustration of " The
Balance of Nature " in this connection. It
seems that the shore-waters are, on the average,
richer in Plankton than any other waters, the
reason being that they are always receiving
abundant supplies of valuable salts brought
down from inland by rivers and streams. So
the shore-waters serve as a sort of nursery of
minute creatures that get swept out to sea to

THE OPEN SEA 103

form the "floating sea-meadows." Thus the
Shore helps the Open Sea. On the other hand,
as we have seen, there are many shore-animals
which depend upon the Open Sea, for it is the
kindly cradle of their fragile youth.

CHAPTER III
THE GREAT DEEPS

The Challenger Expedition— The Deep Deep Sea— Great
Pressure — Very Cold — Very Dark — Very Calm and Silent
— Monotony — No Depth Limit to Life — No Plants in the
Deep Sea — No Rottenness — A Representative Fauna —
Fitnesses of Deep-sea Animals — Puzzle of Phosphorescence
— Big Eyes and Little Eyes — Origin of Deep-sea Animals
— Hunger and Love in the Deep Sea — Retrospect.

TO our forefathers the depths of the sea
were as unknown and as mysterious as
fairyland. Very early, indeed, fishermen had
begun to explore the surface-waters, and had
forced them increasingly to contribute of their
abundance to their support, but the life of the
great depths was absolutely unknown, though
imagination peopled them with strange forms.
As late as the sixteenth century a famous book
by Conrad Gesner contained, mixed up with
illustrations of real animals, pictures of mermen
and mermaidens, tritons, dragons, sea-devils,
sea-bishops, and other fabled monsters.

104

PLATE VII. — THE FLOOR OF THE DEEP SEA.

Showing a dredge being dragged along, three strange abyssal fishes, a
graceful yard-high Umbellula, with a tassel of Polyps at the top and the
base fixed in the ooze.

THE GREAT DEEPS 105

By the beginning of the nineteenth century
imagination was being corrected by scientific
investigation, and people were becoming dis-
inclined to believe more than they could see.
Apparatus for research was still very imperfect,
and we find a great English naturalist, Edward
Forbes, in 1850, declaring his belief that there
are no living animals below 300 fathoms.
And this in spite of the fact that in 1818 Sir
John Ross dredged a Brittle-Star (Astrophyton)
from 800 to 1000 fathoms.

Even when animals were brought up in the
net from considerable depths, it was objected
that there could be no certainty that these were
not caught on the way up. But that living
creatures existed at much greater depths than
had been supposed was suddenly proved beyond
all doubt by an accident. A submarine cable
broke, and when the two ends were fished up
for repair, they were found encrusted with
several different kinds of animals. This dis-
covery gave a great impetus to investigation.
It was too costly for private enterprise, but the
Governments of various countries, Britain,
France, Norway, Italy, and the United States,
took the matter in hand, and expedition after
expedition was sent out, with special equipment

io6 THE HAUNTS OF LIFE

for studying the physical conditions of the great
depths, and obtaining specimens of the animals
that inhabit them.

THE « CHALLENGER " EXPEDITION

The first great expedition was that of the
Challenger (1872-76), which may be called a
Columbus voyage, since it practically discovered
a New World — the world of the Deep Sea.
During three and a half years the Challenger
circumnavigated the globe, cruising over 68,900
nautical miles. The naturalist in charge was
Sir Wyville Thomson, and the staff included Mr.
John Murray (the late Sir John Murray) and Mr.
J. Y. Buchanan. Reaching down with the long
arm of the dredge, the explorers raised treasures
from over 300 stations. The results of this
great expedition were published under Sir John
Murray's editorship in fifty quarto volumes.
These form the firm foundations of oceanog-
raphy— the science of the sea.

It was at first expected that many of the
deep-sea animals would be quite different from
those living in shallower waters, and would
resemble older types now known only as fossils,
but with few exceptions this did not prove to

THE GREAT DEEPS 107

be the case. The deep-sea animals have been
found on the whole to be very similar to others
of the same families living on the shore or near
the shore elsewhere, with, however, certain well-
marked differences, which make them better
fitted for life in their actual surroundings.

Thanks to the efforts of the different ex-
ploring expeditions and to the published records
of their work, we have now some very definite
ideas of the conditions of life at the bottom of
the sea, and of the ways in which animals are
adapted to them.

Every expedition that has been sent out has
carried more and more perfected ^apparatus for
exploring the great depths. It has been found
possible to bring up specimens of the lowest
layer of the water, and of the actual sea-floor
itself, as well as of the animals that lived there.
Thermometers have been devised for register-
ing the temperature, and instruments for
measuring the pressure at different levels.

THE DEEP DEEP SEA

By the deep sea naturalists mean practically
the floor of the deep parts of the sea and the layers
of dark water near the floor. Comparatively

no THE HAUNTS OF LIFE

It has happened repeatedly that a closed
glass thermometer sent down inside a metal
tube has been brought up again powdered to a
fine dust. In one experiment made on board
the Challenger, a thick glass tube full of air
was sealed at both ends, wrapped in flannel,
and put inside a copper tube with holes at each
end. This was lowered to a depth of 2000
fathoms, and was then drawn up again. Not
only was the glass tube powdered, but the side
of the copper case was crushed inwards by the
pressure. Before the empty space caused by
the shivering of the glass tube could be filled
with water, the side of the copper case was
stove in — an "implosion," as one of the ex-
plorers said, had occurred.

Because of the pressure, deep-sea animals
are "liable to an accident to which no other
animal in the world is liable — that of tum-
bling up." Most fishes have a silvery swim-
bladder or air-bladder, which contains gas
and enables the fish to accommodate itself
to different depths. But this accommodation
must take place very gradually, and if a
deep-sea fish, in chasing its prey, rises too
high or too suddenly, its swim-bladder expands
so much that it cannot be controlled by the

THE GREAT DEEPS in

muscles. The fish is therefore unable to go
down to the bottom again, but rises helplessly,
and more and more rapidly, until it reaches
the surface, usually dead, with its body greatly
distended, and sometimes even split open.

VERY COLD

The deep sea is a very cold haunt, for the
sun's heat is practically lost at about 150
fathoms ; and there is a continual sinking down
of cold water, rich in oxygen, from the Poles,
especially from the South. Throughout the
year there is little variation in the abyssal
temperature, which remains at about 28°-34°
Fahrenheit, a little on each side of the freezing-
point of fresh water. Eternal winter reigns.
There are cleverly made thermometers for
taking the temperature of the abysses ; thus,
after the well-protected thermometer has been
down for a while, a metal "messenger" is sent
spinning down the wire, which hits a spring
and turns the thermometer upside down, so
that it cannot change on the way up. In a
similar way water-bottles that collect samples
of the water at, various depths can be auto-
matically closed at any point.

H2 THE HAUNTS OF LIFE

VERY DARK

Very sensitive bromo-gelatine plates, auto-
matically exposed and closed again at a depth
of 500 fathoms — about half a mile — show that
some rays of light reach that depth. For
practical purposes, however, it is dark at 250
fathoms. Thus the deep sea is a world of
dreadful night, and the utterness of the darkness
must be almost intensified, one would think,
by the fitful gleams of " phosphorescent " light
given forth by various deep-sea animals, both
sedentary and wandering. Perhaps it is like
the very badly lighted suburbs of a big town ;
perhaps it is like a moor on a very dark night,
with only a few stars overhead.

VERY CALM AND SILENT

The deep sea is a place of silence and calm,
for no sound can reach the depths, and the
severest storms are comparatively shallow in
their grip. There are no swift currents, but
at most a gentle flow over the beds of ooze.
What is this " ooze " ? Over vast tracts of the
ocean-floor there is an accumulation of minute
particles, as fine as dust, varying in character

THE GREAT DEEPS 113

from place to place. This is ooze. One kind
consists mainly of the beautiful lime-shells of
certain types of chalk-forming animals or
Foraminifera (Globigerinids) which live on the
surface of the sea. When these animals are
killed the shells sink to form Globigerina
deposit, which is very abundant on some parts
of the floor of the Atlantic. Similarly there is
Radiolarian ooze, consisting chiefly of the
beautiful flint-shells belonging to another set
of pelagic animals. Pteropod ooze consists
mainly of the remains of the delicate shells of
certain " sea-butterflies," and Diatom ooze
consists mainly of the siliceous shells of these
very simple pelagic plants. Then there is
what is called " Red Clay," though it is neither
red nor clay, a fine powdery stuff made by the
final disintegration of mineral materials — all
sorts of things reduced to their lowest terms.
In a general way we must think of the ooze as
due to the settling down of "the dust of the
sea." In its softer forms it has been described
as "like butter in summer." If there were
rapid currents the ooze would be swept about
and make life impossible, but it is well suited
for a world of calm. When we think of the

ooze we can readily understand why many of
8

H4 THE HAUNTS OF LIFE

the sedentary abyssal animals, such as the Glass-
Rope-Sponge, are fixed by long stalks, and
why many of the wandering abyssal animals,
such as crabs and sea-spiders, have very lanky
legs, for walking delicately on the treacherous
surface.

MONOTONY

The Deep Sea must be the most monotonous
place in the world. There is no scenery, but
a succession of dreary undulations like those of
sand-dunes. Only here and there are there
ridges like water-sheds or volcanic cones rising
to the surface, perhaps to form the foundations
of sunlit coral islands. Moreover, everything
is so continuous — eternal winter, eternal night,
eternal silence. What an eerie picture this —
a deep, dark, cold, calm, silent, monotonous
world.

NO DEPTH-LIMIT TO LIFE

What of the life of the great deeps ? The
biggest fact is that there is no "deep" too
deep for life. There are more animals at the
more moderate depths ; there are more animals

PLATE VIII. — DEEP SEA NEAR SHORE.

In the shallow shore area, note Crab, Star-fish, Sea Anemone, Seaweed. In
the great depth, note a fish with enormous gape, a young- fish with long-
stalked eyes, two fixed Feaiher-Stars, an Umbellula a yard high, with^the
base of its stalk embedded in the ooze.

THE GREAT DEEPS 115

on the lime-ooze than on the " red-clay" mud-
ooze ; and we do not know much about the
thinly peopled miles of water between the limit
of the light, say half a mile at the most, and
the floor itself. But the big fact is that wher-
ever the long arm of the dredge has reached
down it has brought up living creatures. It is
astounding to read that on the " Michael Sars"
exploration, the late Sir John Murray and Dr.
Johan Hjort worked an otter-trawl with a
spread of 50 feet at a depth of 2820 fathoms,
which is over 3 miles !

NO PLANTS IN THE DEEP SEA

There are, of course, no plants in the great
depths, except the resting-stages of a few Algae
that have sunk down from the surface. We
say, " of course," because all ordinary plants,
possessing chlorophyll (disguised by other
colours in many seaweeds), require light if they
are to live. This raises an interesting question,
for if there are no plants it seems at first sight
as if all the abyssal animals must be eating one
another, which is absurd, as Euclid used to say.
No doubt the deep-sea fish eats the deep-sea
crustacean, and the deep-sea crustacean the

n6 THE HAUNTS OF LIFE

deep-sea worm, and the worm — something
else ; but that cannot be the whole story.

What then is the basis of the food-supply of
the deep-sea animals? The first part of the
answer to this question is, that although there
are no living plants there is often plenty of
dead vegetable matter. Some of this is washed
out from the coastal belt and from the mouths
of rivers, for even at great depths, far away
from the coast, animals have been fished up
with their stomachs full of remains of sea-grass
and even of terrestrial plants. But the greater
part of it comes from the surface, and consists
of the remains of the minute algae or marine
plants which, as we have seen, are so abundant
there. These minute particles of vegetable
matter form the food of many of the smaller
deep-sea creatures.

Secondly, we must remember that dead
animal matter is continually sinking down from
the surface. This consists of minute animals
that have been killed by vicissitudes of tem-
perature and the like, or of particles from the
decomposing bodies of surface animals which
have either fed directly upon plants, or have
been able to elaborate their own food in the
same way as plants.

THE GREAT DEEPS 117

1 In rare cases it may be that organic matter
in the water is simply absorbed by the animal's
body without any direct "feeding" at all, or it
may be wafted into the mouth by tentacles and
cilia, or it may simply sink into capacious open
mouths, as in the case of abyssal sea-anemones.
But many of the animals living on the ocean-
floor are "mud-eaters," and as the rich "ooze "
passes through their food-canal the organic
matter it contains is digested. The same thing
happens in the case of the common earthworm
as it eats its way through the soil, or in the
case of the lobworms on the sandy beach.

It may be asked how we know what deep-
sea animals eat since we cannot of course
actually see what takes place in the dark
abysses. The answer is that the contents of
the food-canal can be studied in animals
dredged up, and also that we can carefully
compare those that are brought up in the
dredge with their near relatives living under
different conditions, and try to make out what
the differences between them may mean.

Thus it is certain that many of the fishes at
the bottom of the sea are voracious flesh-eaters.
Some of them are of the usual wedge-shape,
with long tails, but a great many are quite

n8 THE HAUNTS OF LIFE

different. They have enormous heads with
strong jaws and teeth, and very large round
bodies, so that they look as if they were
" nothing but a mouth and a stomach." Some-
times the lower part of the skin of the body is
so loose that it can stretch to an enormous
extent, and more than once a fish has been
dredged up containing within it, still undigested,
another as big as, if not bigger, than itself !

Before we leave the question of food, we
should be clear in regard to two things — first,
that the absence of living plants in the Deep
Sea is bound to make the animal's struggle for
existence very keen ; and, second, that what
count for most are not the bodies of big animals
that occasionally sink to the bottom, but the
minute creatures which are ceaselessly sinking.
It is rather a pretty picture — the ceaseless rain
of dead animalcules sinking through the miles
of water like snowflakes on a quiet winter
evening.

NO ROTTENNESS

We are accustomed to think of Bacteria as
practically omnipresent, playing many a role in
the drama of life, now helping and again

THE GREAT DEEPS 119

hindering. There are many Bacteria in the
surface-waters of the sea, where they help in
the circulation of matter, but there do not seem
to be any in the great depths. That means
that there is no rotting, for there is no rotting
without Bacteria. If a dead whale sinks to
the floor of the sea, with its flesh compacted
together like pressed beef, it is nibbled to
fragments by crustaceans and other scavengers,
and all of it is devoured or dissolved, save the
cowrie-like ear-bones which are almost as hard
as stone. But the microscopic atomies in their
never-ending shower count for much more than
the carcases of whales.

A REPRESENTATIVE FAUNA

It is interesting to find that the assemblage
of animals on the floor of the Deep Sea is
not a picked one, but very representative.
There are many simple microscopic creatures
— Foraminifers and Radiolarians ; many horny
and flinty (but no calcareous) sponges ; sea-
anemones and corals ; worms of many kinds
in abundance ; star-fishes, brittle-stars, sea-
urchins, sea-cucumbers, and many sea-lilies ;
numerous crustaceans and quaint creatures

120 THE HAUNTS OF LIFE

called sea-spiders, whose precise relationships
are uncertain ; lamp-shells and colonies related
to the sea-mat ; all sorts of molluscs — bivalves,
snails, and cuttles ; the degenerate sea-squirts,
some on long stalks ; and numerous strange
fishes. Here the list ends — for we dare not
include sea-serpents in the abyssal fauna at
least.

Walt Whitman's famous picture, " The World
below the Brine," refers not so much to the
Deep Sea as to the bottom of the sea within
the shore-area in the wide sense. But it is
incomparably fine.

" Forests at the bottom of the sea, the branches and leaves,

Sea-lettuce, vast lichens, strange flowers and seeds, the
thick tangle, the openings, and the pink turf,

Different colours, pale grey and green, purple, white, and
gold, the play of the light through the water,

Dumb swimmers there among the rocks, coral, gluten,
grass, rushes, and the aliment of the swimmers,

Sluggish existences grazing there or suspended close to
the bottom,

Sight in these ocean depths, wars, pursuits, tribes breath-
ing that thick-breathing air, as so many do."

FITNESSES OF DEEP-SEA ANIMALS

Many of the fixed animals of the great
depths have long stalks which raise the

FIG. ii. — FEATHER-STARS OR SEA-LILIES (CRINOIDS).
Growing from the Floor of the Deep Sea.

122 THE HAUNTS OF LIFE

important part of the body out of the treacher-
ous, smothering ooze. This is very well
illustrated by the sea-lilies or Crinoids, distant
relatives of star-fishes, which occur in great
beds like daffodils by the lake-side. Another
very good example is to be found in the
Umbellulas, near relatives of the sea-pens,
where the stalk is sometimes a yard long, and
bears at the top a pendent cluster of polyps,
often of a beautiful blue colour.

As intelligible as the long stalks of many
sedentary animals are the long legs of many of
the wanderers. Some of the deep-sea prawns
are the lankiest animals in existence. Some
of the sea-spiders move about on long legs like
stilts. This is well suited for prowling about
on the surface of the abyssal ooze.

Then there is the exquisite tactility of many.
In a world of darkness, where sight counts for
little, touch becomes the important sense.
Some of the deep-sea prawns have feelers
several times longer than their body. One
crustacean has antennae fully a yard long. The
deep-water fish called Lamprotoxus, captured
off the west coast of Ireland, has a barbule
several times its own length, and yet this long
probing feeler is just an exaggeration of the

THE GREAT DEEPS 123

little tactile organ seen hanging down for about
an inch from the front of the cod's lower jaw.

Another fitness is the delicate build of the
body — such as we see in Venus's Flower
Basket (Euplectella), whose flinty skeleton
rises like a fairy palace from the floor of the
deep sea. When the sponge is living, the
beauty of the skeleton is hidden by the tissues,
and the significance of the skeleton to the
animal is that it forms a scaffolding for lifting
a fairly big body — sometimes about 2 feet
high — off the floor of the sea. The scaffolding
is so delicate that the weight of a child's hand
crushes it, and yet it is more effective than a
solid bone would be to resist the enormous
pressure of the water — many tons on the
square inch. It circumvents the pressure, for
when the water gets through and through an
animal the pressure inside and the pressure
outside are equal. The same applies to the
Glass -Rope -Sponge (Hyalonema), which is
raised on a long stalk of flint fibres, always
bound together by a colony of anemones.
The theory of the adaptation to outside
pressure becomes more difficult when we pass
to animals with a body-cavity, a food-canal,
blood-vessels, and so on, but the general theory

124 THE HAUNTS OF LIFE

remains the same. It is interesting to find
that the bones of some deep-sea fishes are so
lightly built that one can run a needle through
them without breaking the point.

It is not asserted that substantial skeletons
do not likewise occur in the deep waters.
That is another way of solving the problem,
which some of the deep-sea corals illustrate.
But the usual way out of the difficulty is what
we have tried to explain : the pressure is cir-
cumvented by making the whole body very
permeable.

PUZZLE OF PHOSPHORESCENCE

While there are many features of deep-sea
animals which we can interpret as well fitted to
the peculiar conditions, there are others which
are puzzling. One of these is the common
occurrence of light-production. It is difficult
to get rid of the word " phosphorescence " as
a name for the light given out by some living
creatures — both plants and animals. But
whatever be the nature of the light given out
by fire-flies and glow-worms, fire-flames and
sea-pens, it is not phosphorescence. It might
be called chemi-luminescence, for it is a by-play

THE GREAT DEEPS 125

of certain chemical processes in which oxidation
plays a central part. Incandescence is light
given off under the influence of great heat, but
animal luminescence is a "cold light" with
little or nothing in the way of heat rays. In
the cases which have been most studied, the
boring bivalve called Pholas, the luminous
beetles called fire-flies, and the luminous water-
flea called Cypridina, there are always two
substances involved in the animal light. There
is a substance called luciferin, which is oxidised,
and there is a substance called luciferase, which
acts on its neighbour like a ferment. Some-
times the light is given out by a stuff manu-
factured in scattered or definitely arranged
glands, and then it may stream into the water,
or the whole clammy surface of the animal may
sparkle. In other cases, the light is only seen
inside special organs, the luminous organs,
which are often very complex and curiously
like eyes. It is strange that organs which
produce light should sometimes show a very
striking resemblance to organs which detect
light, namely, eyes. If you say that it is not
so very strange, for the cat's eyes shine in the
dark, you are perhaps not altogether wrong,
for although the shining of the cat's eyes is

126 THE HAUNTS OF LIFE

just the reflection of scant gleams of light and
is never seen in total darkness — when animal
light is best seen — there is something quite
useful in the comparison, for the luminous
organs have often reflectors not very different
from the reflector in the back of the cat's eye.

In any case, " animal light" is common in
the deep sea, both in fixed and wandering
creatures. The light-giving stuff or secretion,
which remains luminescent after the animal is
dead, often oozes out on the general surface,
as in sea-pens, and may trail into the water.
In its finer forms, in fishes and crustaceans, it
shines out from complicated lanterns, the special
luminous organs.

The Marquis de Folin, who was with one of
the great French expeditions, describes the
surprise and delight of the naturalists on board
the exploring vessel when they first saw a
deep-sea dredge brought up in darkness. The
dredge contained many coral animals, shrub-
like in form, which threw off " flashes of light,
beside which the twenty torches used for
working by were pale." Some of the corals
were carried into the laboratory, where the
lights were put out. " There was a moment
of magic, the most marvellous spectacle that

FIG.

12. — SEA-PENS AND UMBELLULAS.
Embedded in the Ooze.

128 THE HAUNTS OF LIFE

ever was given to man to admire. Every
point of the chief branches and twigs of the
coral I sis threw out brilliant jets of fire, now
paling, now reviving again, to pass from violet
to purple, from red to orange, from bluish to
different tones of green, and sometimes to the
white of over-heated iron. The pervading
colour, however, was greenish ; the others ap-
peared only in transient flashes, and melted into
the green again. Minute by minute the glory
lessened, as the animals died, and at the end
of a quarter of an hour they were all like dead
and withered branches." But while they were
at their best "one could read by their light the
finest print in a newspaper at a distance of 6
yards."

In the case just described, the light was
apparently given off from the whole of the
living matter covering the limy skeleton, but
very often it comes from particular spots or
" light organs." One cuttlefish has about
twenty of these luminous spots, " like gleaming
jewels, ultra-marine, ruby-red, sky-blue, and
silvery," and another has minute light-giving
points dotted all over its body.

Fishes often have these light-giving spots,
and we are told of one fish which has two large

THE GREAT DEEPS 129

luminous plates just under its eyes. One of
these gives off red light and the other green,
and from the arrangement of the muscles con-
nected with them, it is thought that the fish
has control over them, and can turn on its
lamps at will, to warn off its enemies or to aid
it in the search for its prey !

" Very strange indeed would be the appear-
ance of these animals if we could see them in
the deep ! In the absolute darkness of the
abyss they would appear as ghostly, silver-
blue shapes, glimmering like an electric lamp
through dense fog on a dark, moonless night.
Of all the characters of deep-sea fishes
this almost universal phosphorescence is the
strangest."

Another puzzle may be found in the fact that
many deep-sea animals are brightly coloured.
Bright red is common, for instance, in crus-
taceans, star-fishes, and sea-anemones. There
is very little in the way of pattern, but there is
not a little colour. What can be the meaning
of colour in a world of darkness ? It is highly
probable that the colours as such have no
significance in the life of these deep-sea animals,
that they are simply the useless by-products of
some of the fundamental processes that go on
9

130 THE HAUNTS OF LIFE

in the body. If this is so, they have their
counterpart in the brilliant colours of the
withering leaves in autumn. For these colours,
as colours, are of no use to the trees.

BIG EYES AND LITTLE EYES

Another puzzle of the deep sea is the occur-
rence of fishes with big eyes and of others with
little eyes. If the fishes were all small-eyed
or approaching blindness, it would be easy to
say that in a world of darkness they were
gradually losing their sight, for we know that
gold-fishes kept in absolute darkness for three
years become blind, actually losing the per-
ceiving elements called rods and cones in the
retina of the eye. But what is to be made of
the occurrence of big-eyed and small-eyed
fishes in the same conditions? Perhaps it
might be said that the small-eyed forms have
been longest in the abysses, and therefore show
greater degeneration of the eye. But this
cannot be the whole answer, for in many cases
the eyes are unnaturally large — so large that
they occupy about a fifth of each side of the
head. Sometimes they have become what are
called telescope-eyes, projecting far forward on

THE GREAT DEEPS 131

a cylindrical stalk, so that they are fitted for
making the most of a dim light.

Two answers to the question are possible.
The first is, that though the animals with large
eyes have been dredged up from the great
depths, and probably spend most of their time
there, they may sometimes migrate far enough
upwards to come within the sun's influence,
and it is only if the eyes are never used at all
that they tend to dwindle away.

The second answer is, that though there is
no daylight, there is some light from luminescent
animals. Perhaps it is this uncertain light
which the big eyes use.

Perhaps one of the biggest puzzles is that
the ordinary activities of life, such as digestion
and breathing, seem to go on quite smoothly in
the great deeps, although the conditions of life
are so very different from those to which the
shallow-water relatives of the abyssal animals
are accustomed.

ORIGIN OF DEEP-SEA ANIMALS

Where did the deep-sea animals come
from ? This is a good question, but we do
not yet know enough to be able to answer it

132 THE HAUNTS OF LIFE

as we should like. In a general way the
answer is that most of the deep-sea animals
are derived from shore-animals that migrated
gradually — following the drifting food and sea-
dust — down the slope into the abysses. There
are no very ancient types in the Deep Sea ;
there are much more old-fashioned creatures
in shallow water. It does not seem likely that
any of the present-day deep-sea animals were
established there before the Triassic Age.
Many are probably much more recent.

HUNGER AND LOVE IN THE DEEP SEA

There can be no doubt that there is often
very strict rationing in the Deep Sea. This
is unmistakably shown by the enormous gape
in many of the fishes, by the webbing of the
arms in some cuttlefish to form a capacious
funnel, by the big, soft mouth of sea-anemones,
and by many other hints of hunger.

But the other note is also sounded. The
Challenger explorers found a sea-cucumber
with its fully formed young ones attached to
the skin all along the upper surface. There
are numerous expressions of a kind of parental
care among brittle-stars, especially in the

THE GREAT DEEPS 133

Antarctic. The male sea-spiders from the
deep sea, like those from shallow seas, carry
the bunches of eggs attached to their limbs.
It is also interesting to find that some animals,
whose seashore representatives liberate eggs,
bring forth embryos in the Deep Sea. This
is probably an adaptation which counteracts
the risk of the passive eggs being smothered
in ooze.

RETROSPECT

Let us now gather together briefly what we
have learned, and try to make a mind-picture
of the depths of the ocean.

The average depth is 2^ miles, but there
are " deeps" of over 6 miles, so that the
highest mountain in the world, if thrown
in, would be far below the surface of the
water.

It is very cold; it is absolutely soundless;
it is calm, and quite dark, save for the weird
blue-green light radiating from the corals fixed
in the mud, or from the luminous spots of the
animals slowly moving in and out among these
4 'perpetual light-houses." Star-fishes, sea-
urchins, sea-cucumbers, many kinds of molluscs,

134 THE HAUNTS OF LIFE

many worms, and hosts of other animals lie
buried in the mud, or creep or wriggle slowly
over it. Crabs, lobsters, and prawns with
long legs and long feelers prowl about hunting
for their food ; great, many-armed cuttlefishes
dart hither and thither, and fishes with gaping
mouths and cruel-looking teeth swim very
leisurely, for their bones are spongy and their
muscles soft, perhaps because in these still
waters there has never been any need for great
exertion.

Life is most abundant at a depth of about
2000 fathoms, and it varies in richness according
to the character of the ooze. But no locality
and no depth has yet been discovered which
does not harbour living animals of some
kind.

Verily, if modern scientific research has de-
prived us of our mermaidens and our sea-king's
palaces, it has given us no unfair exchange in
revealing to us this eerie, cold, dark, still world
below the waters.

Not the least of our gains is this, the
demonstration that there are no slums in
Nature. In these inaccessible haunts, in this
world of darkness, there is the same order,
the same fitness, the same finished perfection,

THE GREAT DEEPS 135

the same beauty that we find elsewhere. As
William Watson has well said :

"Nay, what is nature's
Self, but an endless
Strife towards music,
Euphony, rhyme ?

Trees in their blooming,
Tides in their flowing,
Stars in their circling,
Tremble with song.

God on His throne is
Eldest of poets ;
Unto His measures
Moveth the whole."

CHAPTER IV
THE FRESH WATERS

Variety of the Fresh Waters — Similar Animals in widely separated
Places — From Salt Water to Fresh — Origin of Fresh-water
Animals— Circulation of Matter in the Fresh Waters — The
Web of Life in the Fresh Waters— The Danger of Drought
—The Danger of Frost— The Danger of Flood— Parental
Care among Fresh-water Animals — The Story of the Eel —
The Story of the Salmon — The Story of the Lamprey —
Water Insects— The Story of the Fresh-water Spider.

THE fresh waters do not occupy even a
hundredth part of the earth's surface —
1,800,000 square miles out of the 197,000,000,
which form the total. But the haunt makes
up for its relatively small size by its great
variety.

VARIETY OF THE FRESH WATERS

There are lakes so vast that their depths
may be as cold, and dark, and plantless as
those of the sea itself. Lake Baikal in Asia

has a depth of 760 fathoms, with an additional

136

THE FRESH WATERS 137

atmosphere of pressure for every 5 fathoms, and
there are seals in its waters. There are shallow
ponds of all sizes which vary greatly in tem-
perature from day to night, and from season
to season. They may bear a foot of ice in the
depths of winter, and be dried up altogether in
the heat of summer. Yet year after year these
shallow ponds show an abundance of life. It
may be noticed that the strict difference
between a pond and a lake is not in size, for
a pond may be a mile long, but in depth, for
a true pond is always shallow. Then there
are the lonely mountain tarns with their dark,
mysterious waters and a rather sparse animal
population ; there are great rivers and purling
brooks, swift torrents and sluggish streams
with little fall ; there are marshes grading into
the shore, and others passing insensibly into dry
land. There are also artificial fresh waters, as
in canal and quarryhole. There is a consider-
able fauna in the water-supply of some cities.

SIMILAR ANIMALS IN WIDELY
SEPARATED PLACES

A striking feature about the fresh-water
animals is that they are often the same or

138 THE HAUNTS OF LIFE

nearly the same in widely separated basins.
A lake in the Scottish Highlands, one of the
thousand lakes of Finland, a lake in Japan,
may have similar tenants. Why is this? It
is partly because water-birds carry the same
small animals on their feet, or in clodlets on
their feet, from one lakeside to another, because
the wind sometimes does the same, and because
changes in the surface-relief of the earth's crust
not only make valleys separate from one
another, but bring them together again. But
the most important reason is probably that the
animals which colonised the fresh waters came
for the most part from the shore, and that only
certain kinds of constitution could stand the
change. Let us think for a little what the
change from the shore to the fresh waters
would mean, always bearing in mind that it
would be a very slow and not a sudden change,
for most salt-water animals die immediately if
they are put into fresh water.

FROM SALT WATER TO FRESH

What characters or qualifications were
necessary before the transition from salt water
to fresh water could be even attempted ?

THE FRESH WATERS 139

The first and most important of these was
the power to endure slight changes in the
degree of saltness. This power would be
found most frequently in animals that lived in
the shore area, for there such changes occur
very often. Heavy rain falling into the smaller
pools may make them comparatively fresh, and
will also affect the shallow water of the sea
itself, though not to the same degree. About
the mouths of streams and rivers, too, the
water is fresher than elsewhere, and the tides
carry up so much salt water that the estuaries
are salt, or at least brackish, for a long way
up, and only very gradually become quite
fresh.

It was, therefore, probably by this route that
the rivers and lakes got a great part of their
inhabitants. We can easily picture some of
the more adventurous of the shore animals
making their way slowly up the river mouths
until — not in a single lifetime, let us remember,
but in the course of many generations — they
got beyond the influence of the tide altogether,
and settled down in fresh water.

The move seems to have been so successful,
in some cases at least, that the enterprising
colonists increased abundantly, and some of

140 THE HAUNTS OF LIFE

them have survived even though all their
nearest relatives in the sea have disappeared.

Others* again, after long, long ages, seem
never to have become quite at home in fresh
water, but have to go back periodically to their
original home in the sea to deposit their eggs,
so that the change from salt water to fresh has
to be made by every individual in its own life-
time. The eel is one of these, and its life-story
is so interesting that we shall follow it in detail
later on.

Another qualification necessary for migrating
up the rivers was one which nearly all fresh-
water animals must possess — the power of en-
during considerable changes of temperature.
This power, too, would most frequently be
found among the shore animals, for, as we have
seen, those living in the open sea have only to
sink beneath the surface to protect themselves
from sudden changes, while in the deep sea the
temperature remains always about the same.

ORIGIN OF FRESH-WATER ANIMALS

But there is a previous question : Why do we
think that fresh-water animals must have come
from the sea ? May they not have begun to be

PLATE IX.— A FRESH-WATER POOL.

Showing Trout, Minnow, Crayfish, Fresh-Water Mussel, a little Crustacean
called Gammarus, a young Dragon-fly creeping on the reeds, Adult
Dragon-fly, and Mayflies in the air.

THE FRESH WATERS 141

where they are now ? To answer this very
reasonable question briefly is not possible, but
part of the answer may be given. Among the
first animals to have bodies — namely, the
Sponges — we find one family in the fresh waters,
and all the rest — including many hundreds of
different kinds — in the sea. That is a straw
which shows how the wind blew. Among the
Stinging Animals which come next in order —
the sea-anemones and corals, the jelly-fishes and
zoophytes — only about half a dozen are found
in the fresh waters ; all the rest — thousands of
different kinds — live in the sea. So in many
other cases, and the home of the great majority
of any great race of animals is likely to be the
original home of the race.

Another step in the argument is the Natural
History rule that when an animal has more
than one habitat in the course of its life-history,
the one in which it starts another generation, or
begins its own life, is usually the original home.

The robber-crab wanders far from the shore
and even climbs the hills, but it goes back to
the seashore every year to spawn, and there is
no doubt at all that it was originally a shore
animal. So the fresh-water eel goes to the deep
sea to spawn, and there is almost no doubt that

142 THE HAUNTS OF LIFE

its ancestors were deep-water fishes. Similarly,
though the flounder is often found in rivers
20 miles from the sea, it does not spawn in
fresh water, it must go back to its old home in
the shallow sea. It will be interesting to think
out some cases that seem to break this rule.

It is also to be remembered that some animals
are at present making the transition from salt
water to fresh. The flounder is a case in point,
undoubtedly a marine fish, but becoming more
and more accustomed to the rivers. The
quaint Manatee, included with the Dugong in
the small order of mammals, known as sea-cows,
or Sirenia, is typically a coastal mammal, but it
goes far up the rivers, and it is now found, for
instance, in the Everglades of Florida, a far cry
from the sea.

In any case we should not think of the fresh-
water fauna as a fixed and finished assemblage
of animals. It is a noteworthy fact that many
fresh-water animals spend only a part of their
lives in the fresh water. Some of these seem
to be still in process of accustoming themselves
to it, others to be leaving it for salt water, and
others again are apparently on the way to
becoming land animals.

How can we tell in which direction a par-

THE FRESH WATERS 143

ticular form is tending — whether it is becoming
more of a fresh-water animal or less ? The
process of change in an animal race may go on
so very slowly that at a given point we cannot
detect it at all. But that is not to say that it
is not taking place. It has been said that if a
clock could be invented that would go so slowly
that it would only tick once in thirty years, we
should not believe that it was going at all. Yet
even that rate is fast compared with the rate at
which Nature works out some of her wonderful
changes.

But though we may not hope to detect Nature
actually at work, there are various ways by
which those who study her closely can trace out
some of the changes that have taken, and are
still taking, place. One of these is by compar-
ing one kind of animal with another closely
related to it, and trying to make out the meaning
of the differences between them. Sometimes so
many kinds of animals, with only slight differ-
ences between each kind, are found that they
can be arranged in a regular series, and it is
possible to be fairly certain of the path along
which the race has travelled.

Another way is by studying the growth of a
particular animal from the time that it begins to

144 THE HAUNTS OF LIFE

form within the egg. For every animal in its
early life tends in a greater or less degree to
repeat in its personal history some of the stages
that have been gone through in the history of
its race, and much of this can be made out by
a careful study of the stages that appear, often
to disappear again very quickly, in the earlier
period of the building up of the body of the
individual.

The same thing is true to some extent of
habits, and, in particular, many animals have
an impulse to go back at the breeding-season
to bring forth their young in the place where
they themselves first began life. Therefore,
when we find an animal leaving the haunt in
which the greater part of its life is passed, to
bring forth its young in quite a different one,
we have good grounds for believing that its
ancestors once had their home in the haunt to
which it returns.

But there is a difficulty here which must be
faced. There are some cases in which the
youthful stages are passed in a haunt which
was certainly not the original headquarters.
A good illustration of this may be found in
insects like May-flies and Dragon-flies, Caddis-
flies and Alder-flies, Gnats and Harlequin-flies,

THE FRESH WATERS 145

whose larvse live in the fresh waters. But no
one can suppose that these insects, or any insects,
had their original home in water. The explana-
tion is that when an animal lives in a haunt full of
dangers for the young, it has often circumvented
the difficulty by finding another haunt for the
juvenile stages. The aquatic larvse of insects
are not old fashioned ; they show new-fashioned
fitnesses to a haunt which is really rather foreign
to the insect's nature.

CIRCULATION OF MATTER IN THE
FRESH WATERS

To understand the animal life of a lake or
pond we must as usual start with the plants.
For the plants, which are able to feed upon
the not-living, supply food for the animals which
feed upon the living, or what has been living,
or what has been made by something living.
There are many fresh-water plants growing
round the margin, like bog-bean, mare's tail,
iris, and bullrush ; others, like water-lilies, are
rooted at a considerable depth, and send their
leaves and flowers on long stalks up to the
surface ; others, like duckweed, with roots, and
bladderwort, without roots, float freely. Now

10

146 THE HAUNTS OF LIFE

there are animals that browse on these plants,
and other animals that thrive on the broken-
down fragments of these plants, when they decay.
But important as these big plants are, they are
not so fundamental as the immense number of
simple plants that float in the surface-waters

MUD AND
MANURE

IN INFUSORIA

FISHERMAN

FISH.

TROUT

FIG. 13. — BLACKBOARD DRAWING OF CIRCULATION OF

MATTER.

Bacteria break down the Mud and Manure ; the results and
the Bacteria are eaten by Infusorians ; these are devoured
by Water-fleas, and these by Fishes, and a higher incarna-
tion is in Man.

—the fresh-water Algae. These often make the
water like green soup ; and there are often far
more of them in a pitcher than we can see of
stars on a frosty night. It is on them that
the economy of the pond or lake mainly
depends.

THE FRESH WATERS 147

These minute plants are the chief producers
in the fresh-water community. The animals
are the consumers, though many of them
devour their smaller neighbours, who might
therefore rank among the producers. When an
animal dies in the water, the Bacteria which cause
all rotting break down its body into salts and
gases. The salts, sooner or later, often with
the help of other Bacteria, become the food of
aquatic plants, and the gases pass into the
air or are captured in the water before they
get so far. Thus the Bacteria are the
middlemen.

The experiment has been made of putting
mud and manure in boxes round the edge of a
fish-pond, which tended to " give out" periodi-
cally, apparently because the water was too
sparsely peopled. Bacteria worked at the
material in the boxes and made it available for
the microscopic animals, called Infusorians,
which always abound where there is rotting
organic matter. The Infusorians devoured
what the Bacteria prepared, and some of them
devoured the Bacteria too. A living cataract
of Infusorians fell into the pond and formed the
food of water-fleas or Copepods, which in turn
were eaten by fishes. What was part and

148 THE HAUNTS OF LIFE

parcel of the mud and manure became, through
the middlemen Bacteria, part and parcel of the
Infusorians. These were incorporated in water-
fleas, which, in turn, found a new incarnation in
fishes. What was part and parcel of the fish
became part and parcel of man. And so the
world goes round. If we believe that fish-food
is good for the brain, as some doctors tell us, we
may trace the links of a chain between mud and
clear thinking.

The sturdy fern, called Bracken, is doing much
harm in Britain and other countries by destroy-
ing pasture land. It kills out the grass and
other useful plants, and it is so vigorous that it
can conquer even the heather. One wishes,
therefore, that there might be a wholesale
repetition of the experiment of tumbling cart-
loads of bracken into fresh-water lochs. The
result, where it was tried, was the great improve-
ment of the fishing. For the bracken tumbled
into the water was acted on by Bacteria,
and rotted, providing food for Infusorians, which
in turn gave sustenance to water-fleas, as these
to fishes. If we cast bracken on the waters, we
may get, after many days — not bread exactly,
but trout !

THE FRESH WATERS 149

THE WEB OF LIFE IN THE FRESH
WATERS

Nowhere do we find better examples of the
web of life than in the fresh waters, meaning
by the web of life the linkages between living
creatures, binding them together. Here are
some examples.

The eggs of the common salt-water mussel
are wafted out into the sea and develop into
free-swimming larvae, which eventually settle
down ; but the eggs of the fresh-water mussel
are retained inside the shell and develop in a
special brood-chamber, the cavity of the basket-
work-like outer gill. They develop into tiny
pinhead-like larvae, called Glochidia, each with
two valves toothed at the margin. The eggs
are produced about midsummer in Britain, but
the Glochidia are not allowed to escape till early
in the following year. They are not allowed
to escape unless a fish, such as a minnow, comes
swimming slowly past. Then the mother-
mussel allows some of her offspring to escape,
and they come crowding out, like boys set free
from school, clapping their valves in the water
and exuding delicate gluey threads. Some of
them are lucky enough to get attached to the

150 THE HAUNTS OF LIFE

skin of the minnow ; the others perish. The
Glochidia are somehow attuned to answer back
to minnow, and if we have some in a soup-plate
they become greatly excited if a little piece of
dead minnow is dropped into their midst. In
some North American fresh-water mussels it is
to one kind of fish, and to that alone, that the
larvae respond. So subtly interlaced are the
threads of the web of life. But returning to our
own rivers and ponds, we find that the Glochidia
remain for a considerable time on their bearer,
the minnow, burrowing a little way into the
flesh, and undergoing a great change in the
architecture of their body. When the great
change or metamorphosis is accomplished, they
drop off into the mud and start an independent
life as young fresh-water mussels, often far from
the place where they were born. We under-
stand then that the fresh-water mussel cannot
continue its race unless there is this strange
linkage with a minnow.

And just as the mussel is linked to a fish, so
there is a fish which is linked to the mussel.
For the Bitterling, Rhodeus amarus, which
lives in some continental rivers, has a long egg-
laying tube with which the eggs are actually
injected into the fresh- water mussel. The eggs

THE FRESH WATERS 151

develop in the gill-chamber, and the larval fishes
spend some time there before they find their
way out.

Another linkage of the fresh-water mussel is
in connection with pearls, for some of the pearls
are due to the larval stages of parasitic worms
— allied to the liver-flukes — the adults of which
live inside aquatic birds. When the microscopic
parasite settles down in the skin-fold or mantle
of the mussel, it is smothered in layer after
layer of translucent lime, mingled with a little
organic matter, and the result is — a pearl.

The pied-wagtail, so often seen curtseying
on the stones by the side of the stream, is linked
to successful sheep-farming, for it is < very fond
of the little water-snail (Limncea truncatula]
which harbours the juvenile stages of liver-fluke,
which often causes fatal liver-rot in sheep.

Some authorities say that the decline of
Greece was partly due to the introduction of
malaria. If this be so, we may link the decline
of Greece to the mosquito which harbours and
spreads the microscopic animal that causes
malaria in man. The malaria-organism, Plas-
modium by name, is imbibed along with the
blood when the mosquito bites a malaria patient ;
it goes through complicated changes within the

152

THE HAUNTS OF LIFE

FIG. 14. — LIFE-HISTORY OF GNAT OR MOSQUITO.

I. Raft of Eggs. 2. Newly hatched Larvae. 3 and 4. Larger Larvae
breathing by the Tail-trumpet at the Surface. 5 and 6. Pupae, with
Breathing-tubes on Head. 7. Winged Insect emerging from Pupa-
case and flying away.

THE FRESH WATERS 153

mosquito and multiplies there ; when the
mosquito bites another man it infects him with
the malaria germs of which it is the carrier.
Pouring a little paraffin on stagnant pools so
alters the nature of the surface film that the
larval mosquito, which lives in the water, can no
longer hold on to it with its breathing-tube, and
dies for lack of oxygen. Moreover, as there
are little fishes that greedily devour the larvae
of mosquitoes, and are very useful in water-
tanks where the use of paraffin is impossible,
we may actually link little fishes to the decline
of Greece. " Ye gods and little fishes ! "

THE DANGER OF DROUGHT

Life in fresh waters has its peculiar difficulties,
and the three greatest are : DROUGHT, pROST,and
FLOODS. Especially in warm countries is there
great risk of the pool drying up. Little wonder
then that many fresh-water animals have learned
to lie low in a state of latent life. Some small
crustaceans have been known to lie for forty
years in dried mud, without losing the power
of actively living when the mud was moistened
again. A naturalist visiting Jerusalem took a
little mud from the pool of Gihon, at the Jaffa

154 THE HAUNTS OF LIFE

Gate, and put it in a pill-box. It lay dry for
forty years, but, when some of the dry dust was
then put into a saucer full of water, it gave rise
after a short time to some lively water-fleas.
Their resting-eggs had retained their vitality for
longer than an average human lifetime. This
explains why pools, which have been dry for
several years, are found teeming with little
creatures soon after they have been once more
filled with water. The power of lying low in the
mud also helps us to understand what we con-
sidered already, that similar fresh-water animals
often occur in widely separated basins. For
mud may be transported for long distances in
various ways, e.g. on the coats of cattle, and on
the feet of birds. When the caked mud is
dissolved off in the water, the minute animals
may become lively again, or sometimes it seems
to be their well-protected eggs that have sur-
vived.

In tropical Africa there is a strange fish
which has lungs as well as gills. It is known
as the " mud-fish " because, when the water of
the lake in which it lives gets very low, it
burrows down into the mud, and works itself
round and round until it has formed a complete
mud-casing round its body. This dries and

THE FRESH WATERS 155

hardens, and the fish lies safely within it until
the rainy season comes, and the lake is once
more filled with water. Specimens have been
brought to this country within their mud-nests,
and they sometimes come out all right, even
after they have been out of the water for nine
months. A fish out of water indeed !

FIG. 15.— THE QUEENSLAND MUD-FISH (NEOCERATODUS).
Breathing by Lungs as well as by Gills.

THE DANGER OF FROST

In many parts of the world one of the severest
trials of life is the freezing of the water. Even
a resourceful animal, like an otter, may be
starved, because the water is frozen, or it may
venture through a hole in the ice and fail to
find its way back again. Many small fresh-
water animals die altogether in the winter, and
only their eggs live on, protected within hard
envelopes. The fresh-water sponge on the
stones of the river and lake dies away, and in
the late autumn it looks as if it were rotten.

156 THE HAUNTS OF LIFE

But it does not wholly die. Pinhead-like
clumps of cells, called gemmules, protected
within a sphere of beautiful capstan-like spicules
of flint are formed throughout the dying body
of the sponge, and these rest through the
winter and start new sponges in the spring.
It is interesting to compare this partial dying
with what happens to the floating bladderwort,
and to some other water-plants. The bulk of
the plant dies, but the end of each shoot,
heavily laden with stores of starch, breaks off
and sinks to the floor of the lake, rising again,
lightened, in spring, to start a new floating
plant.

Of great importance for living creatures is a
peculiar property of water — almost a unique
property. It has its maximum density — that
is to say, is most closely packed together — at
4 degrees centigrade. When it cools below
this, towards freezing, it expands, instead of con-
tracting as almost all other substances do when
they pass from a liquid to a solid state. The
expansion of the freezing water means that the
water at the bottom of the pond rises to the
surface as it cools below 4 degrees centigrade,
and there forms a protective floating blanket of
ice. As more freezing water rises the blanket

THE FRESH WATERS 157

of ice thickens, and this tends to prevent the
water of the pond from becoming colder and
colder and eventually solidifying. For eighty-
five days in the year — the winter season — the
warmer water of the fresh-water basin is at the
bottom ; the pool does not become solid ice,
except in very rare cases ; the fresh- water
animals are able to continue year in, year out,
and from this many consequences flow.

THE DANGER OF FLOOD

Another great risk — in streams, especially —
is that of being washed down to the sea, or
carried out into a flood-bed and left high and
dry, or in stagnancy. We can understand,
then, why many fresh-water animals, such as
brook-leeches and insect-larvae, have gripping
organs or suckers which anchor them.

But another method of circumventing the
danger of being washed away is to shorten
down the juvenile stages of the life-history,
when the risks are greatest. It is useful to
think of an animal's life-history as a whole —
egg, embryo, larva (if there is such a stage),
young creature, adolescent animal, full-grown
animal, ageing animal, and to think of it as a

158 THE HAUNTS OF LIFE

band, parts of which are elastic, so that they
can be stretched out further or shortened down.
Thus some animals have a very long embryo
period (like Peripatus), others a very long
larval period (like May-flies), others a long
childhood (like kittens), others a long maturity
(like horses). When it is necessary, a part of
the life-curve can be, as it were, stretched out
in the course of generations — man is stretching
out his youthful period — and another part can
be shortened down. Many fresh-water animals
have shortened down the riskful juvenile period.
A clear example of what we mean may be
found in the fresh- water crayfish. It is as high
up the genealogical tree as the lobster, and
almost as high up as the crab. But while the
shore-crab has a long life-history, sketched in
our study of the seashore, with one larval stage
after another, the young of the fresh-water
crayfish is hatched as a miniature of its parent.
It is practically identical with its parents,
except that the tips of its claws are bent in, the
better for gripping the empty egg-shells which
are glued to the swimmerets of the mother. It
has no larval stages to pass through ; it remains
in shelter under its mother's tail until it is able
to fend for itself. Indeed, the young crayfishes

PLATE X.— A FRESH-WATER POOL.

Showing- on the surface Water-Lilies, Duckweed, some insects (Water-
Measurers) gliding on the surface, a Water-Snail gliding back downwards
below the surface-film. Below may be seen a Crested Newt, two Water-
beetles (Dytiscus), a Water-Spider and her dome-like Web; also a Sponge
growing on the bulrush.

THE FRESH WATERS 159

that have begun to swim about often seek the
shelter of the mother's tail, as chickens the
hen's wings. This shortening down of the
chapters of the life-history is an adaptation that
tends to circumvent some of the dangers of
youth.

The time taken to grow up may vary even
among the same animals according to the
season, and may be very different in two closely
related species. There occurs throughout
Central Europe a larger cousin of our common
newt, known as the " fire-salamander," from
the large splashes of orange colour on its black
body. It brings forth its young alive, but still
surrounded by the egg envelope, which bursts at
once, setting free a gill-bearing tadpole. This
little creature does not take on the salamander
form, or leave the water until it is about three
and a half months old. But if the summer is
dry, and the water in the pools gets low, the
stages are gone through more rapidly, and
development may be complete at the end of
two months. This salamander is not found at
a greater height than 2500 feet. Above that
its place is taken by another very similar form
without the orange spots, known as the black
salamander. This form may occur up to a

160 THE HAUNTS OF LIFE

height of 9000 feet, where it is above the
region of pools and quiet brooks, and no water
is available, except the cold, swift mountain
streams, in which tadpoles could not live or
find food. The black salamander, therefore,
does not go through a tadpole stage at all ; the
young are miniature copies of the parent at
birth. Moreover, there are never more than
two of them, while the salamander of the plains
may produce as many as seventy tadpoles in a

FIG. 16. — THE SPOTTED SALAMANDER (SALAMANDRA MACULOSA).
From a Specimen. The Natural Size is about 5 inches.

season. For the pools of the plains are full of
hungry little fishes, newts, water-beetles, and
their greedy larvae, and a hundred other
carnivorous creatures. So there must be
tadpoles enough to ensure that some at least
will survive and carry on the race. The
mountain salamander, born fully formed, and
able, like its parent, to hide among damp leaves
and in holes in the ground, has not nearly so
many risks to run.

THE FRESH WATERS 161

PARENTAL CARE AMONG FRESH- WATER
ANIMALS

The common little Bullhead, or Miller's
Thumb, has also to take precautions against
having its eggs washed away or damaged by
running water. This little fish is regarded
with some awe by country children, because it
apparently utters a cry when it is caught and
taken out of the water. But the "cry" is no
more produced by vocal organs than is the
buzzing of the bee, or the chirping of the grass-
hopper. The bullhead, in common with a
good many other fishes, has the habit of
supplementing its gill-breathing by coming to
the surface and swallowing a mouthful of air,
and it is the sudden rush of this air out of its
body that causes the sound. The bullhead
lives a solitary life, usually hidden among the
stones at the bottom of a rapid stream. It
scoops out a nest beneath a stone, to the under-
side of which it fastens its cluster of eggs.
Unlike the lampreys, which show no care for
their eggs after they have been deposited, the
male bullhead remains on guard over the eggs
and young fry for about a month. Then the
family breaks up, and the young ones seek out

ii

1 62 THE HAUNTS OF LIFE

solitary places in which to hide during the two
years that must pass before they become mature,
and are ready to look for a mate.

Even more interesting in its habits is the
common three-spined stickleback, and, in its case
also, it is the father, not the mother, that shows
parental care. The male stickleback constructs
a barrel-shaped nest of parts of water-weeds,
glued together with a sticky substance from its
own body. This nest is open at one end, and
may be either on the ground or attached to
water-plants. When it is ready, the stickleback
goes off in search of a mate, and escorts her
"with evident pleasure" to the nest. After
depositing her eggs, the female fish makes her
escape by the simple method of breaking a hole
in the nest, usually at the side. Another and
another female is brought till the nest is
sufficiently full. Then the proud father sets
himself to watch over the eggs, keeping them
clean, and fiercely driving away all intruders.
When the young fry hatch out, his labours are
by no means over ; indeed, they are more
arduous than ever, for he tries to keep his
numerous children safely at home as long as
possible, but as fast as he drives them in at the
front door they wriggle out again at the back !

THE FRESH WATERS 163

The stickleback's sharp spines and fighting
temper protect him from larger enemies, for
even a pike hesitates about swallowing so
prickly a creature. But his curiosity is often
the undoing of him, for he will snap at the most
unlikely bait, even when food is abundant.
Their numbers are kept down by man, because
of the damage they do in eating the eggs of
the trout.

THE STORY OF THE EEL

Although the common eel (Anguilla vulgaris)
is not wholly a fresh-water animal, it spends
most of its life in this haunt, and this is the
best place for discussing its extraordinary life-
history.

If we are on the look-out beside any of our
larger rivers during April and May, we may
have the good fortune to see the " eel-fare," as
it is called. Thousands upon thousands of tiny
"elvers," about 2^ inches long, and the thick-
ness of a bone knitting-needle, are making
their way from the sea up the rivers. They
keep close to the banks at each side and form
an unbroken procession that may take many
days to pass a particular spot. They travel

1 64 THE HAUNTS OF LIFE

only in sunlight, and a passing cloud will cause
them all to disappear like a flash, but when the
sun shines out again they swim steadily on
their way.

It used to be the custom in some places to
catch these little creatures in baskets, to use
them for bait, or even to fry them in cakes.
But in other places it is realised that this is a
short-sighted policy, since the full-grown eels
are much more valuable as food. Instead,
therefore, of trapping the elvers, people some-
times hang ropes of straw over the rocky places
to help them on their way up the river.

From the rivers the elvers push on into the
smaller streams and people the ponds and lakes
connected with them. If the water or the food-
supply in one pond gets low, they have no
difficulty in finding another, for, unlike most
fishes, they are able to live for a considerable
time out of water, and they have a way of
wriggling themselves through damp grass for
quite considerable distances. One naturalist
tells us that he kept two small eels for a time
in an aquarium, and " they passed most of the
day buried in the sand at the bottom, but night
after night they made their escape and were
always found in the morning at the other side

THE FRESH WATERS 165

of the room, apparently dead ; however, when
returned to the water they swam about
apparently none the worse for their excursion."
Once settled down in suitable quarters the
elvers begin to feed and to grow, and are now
known as " yellow eels." Their food consists
at first of worms, larvae, and small fishes, but
as they grow they become very voracious, and
will attack water-voles and water-fowl, and
even larger fishes, among which they do serious
damage. There is even a case on record of
an eel, 5 feet long, which attacked a swan !
The owner saw the swan struggling violently,
with its head under water. He went to its
assistance and found that its head had been
seized by a large eel, which held on so
obstinately that it allowed itself to be caught
and landed.

About the third summer of an eel's life in
fresh water its scales begin to grow. It is an
interesting fact that naturalists can tell the age
of an eel, or at least the length of time it has
spent in fresh water, by examining its scales
under the microscope. Each scale is arranged
in little zones or rings studded with tiny, limy
knobs, separated by narrow rings of smooth
material. "This structure is due to the fact

1 66 THE HAUNTS OF LIFE

that the eel feeds and grows actively in the
summer months only, and the zones are annual
rings formed during the summer, whilst the
narrow interspaces represent the growth of the
scale during the colder months."

After a varying time, usually four to six
years in the males, and seven to eight in the
females, the yellow eels begin to change to
"silver eels." Their eyes grow larger, their
pectoral fins longer, and they become silvery-
white on the under-side of the body. This is
their breeding-dress, and they are putting it on
in preparation for the long journey back to the
sea.

They have practically ceased to feed by this
time, and they make the journey down the
rivers in vast numbers, just as they came up.
But this time they travel by night, and then
only when it is quite dark ; bright moonlight,
or a flash of artificial light, will send them into
hiding at once. During this journey they are
caught in great numbers in traps and nets of
all kinds, for at this stage they are much valued
as food, though in Scotland, for instance, there
is a good deal of prejudice against them.

Both the last chapter and the first in the
story of the eel's life remain obscure. No one

THE FRESH WATERS 167

has yet identified the eggs with certainty, nor
the very youngest forms of the fish. Minute
fry are now known, however, which grow into
3-inch long transparent larvae, which feed
near the surface of the Atlantic by night,
and sink deeper through the day. Some
of these " Leptocephalids," which had long
been a puzzle to naturalists, were kept in an
aquarium, and their gradual transformation to
the elver stage was observed. Then many of
them were taken at different times from the
sea, and it was learnt that towards the end of
summer they begin to undergo a change into
the "glass-eel," or "transparent elver" stage.
At the same time, apparently, they begin their
migration towards the shore. The process of
changing goes on for many months, and, during
that time, they do not feed at all, but live on
their own substance. The elver is not only
quite different in shape from the earlier form,
being now a small eel, but it is fully half an
inch shorter.

As to the last chapter, it is supposed that
the silver eels from the British Isles go out
to the deep waters of the Atlantic and there
deposit their eggs, which rise to the surface
and float till they hatch. The eels themselves,

1 68 THE HAUNTS OF LIFE

like many other animals, probably die after the
eggs are safely deposited, for none of them
ever reappear at the coasts or in the rivers
after spawning.

There are only a few species of eel which
enter fresh water ; the great majority of the
family spend their whole lives in the sea, many
of them in deep water. Moreover, some in-
dividuals, even of the common eel, do not enter
the rivers, but probably remain about the
estuaries till it is time to return to deeper
water.

On the other hand, some yellow eels do not
return to the sea. They may have settled down
in ponds which they found it easy to reach
when they were little elvers, but difficult to
escape from later, or they may lack the impulse
to migrate. Such eels may live a long time
and grow to a great size, but they never
produce eggs.

All these facts justify the conclusion that the
common eel is descended from ancestors which
were entirely sea-fish, and that it has taken to
a fresh-water life. Whether it will go farther
in the same direction, we have no means of
knowing.

We have followed this story at some length,

THE FRESH WATERS 169

partly because it is so wonderful in itself, but
partly also so that we may get some under-
standing of the methods by which naturalists
interpret for us some of Nature's stories, and
of the long and patient labour that is required
to determine the facts.

THE STORY OF THE SALMON

Let us now think for a little of another life-
story that is in some ways just the opposite of
the eels — that of the King of Fishes, the
Salmon, which is so valuable as a food, and
which is also prized, because its courage and
strength make the catching of it good sport.

Salmon ascend most of our larger rivers — if
they are clean enough — every year, but not in
swarms as the eels do ; they continue to go up
throughout the spring and summer. Nor are
they all of one age and size like the eels. But
all of them are impelled by the desire to
reach a suitable breeding-place. They are in
the finest possible condition when they enter
fresh water — fat, with firm, red flesh and silvery
skin — for they have been feeding hard and
laying up stores of food-material and strength,
which have to last them till after the spawning-

1 70 THE HAUNTS OF LIFE

time, often many weeks ahead. While in fresh
water they feed very little, if at all.

They need all their muscular energy, too,
for there are many obstacles to be overcome
on their way up the rivers, and the salmon gets
his name from his power of leaping. They
are said to be able to leap up falls as high as
10 feet, and their courage and persistence in
returning again and again to the charge after
failure has thus been described : " The lithe
body, less silvery than usual, shot out of the
water ; then followed a plucky rush amid the
bubbles ; then in seven cases out of ten the
fish was swept back before it had cleared the
second rung of the ladder. It was as exciting
as a race-course. The favourite cleared one
barrier after another, lost energy at the last,
and was swept back like a log, while another,
with less dash about him, cleared every one,
and shot ahead in the swift, smooth, sullen
water above the fall. There was pathos in the
passivity with which the unsuccessful swimmer
let himself be swirled back to the eddies at the
foot of the ladder. Like a spent horse, he
could no more, but one knew that he was set-
ting his teeth, so to speak, for the next rush."

Arrived at the spawning-place — a gravel

THE FRESH WATERS 171

bed in a shallow part of the river — the female
salmon lashes out a trough with her tail, and
in it deposits her eggs, moving gradually up
stream as she does so. The attendant male
meantime keeps all intruders fiercely at bay.
After spawning the salmon are much exhausted,
and they linger for a time in the deep pools to
recover, but they do not begin to feed actively
even then, and many of them die of weakness
or disease on their way back to the sea.

The young fry emerge in early spring and,
for the first few weeks, remain quietly hidden
among the gravel, depending for nourishment
on the stores laid up for them in the egg, and
now attached to their bodies as a yolk-sac.
When the yolk is exhausted, and they are about
an inch long, they become more active, and
seek for their own food. During all this time
both eggs and fry are preyed upon by many
enemies, of which the eels, pike, and fish-eating
birds probably do most damage. But the
young ones that are left, now known as "parr,"
continue to feed and grow for a couple of years,
and then, assuming more silvery hues, descend
as "smolts" to the sea. At this stage they
are about 6 or 7 inches long, but the
abundance of food in the sea, where they live

172 THE HAUNTS OF LIFE

chiefly on herring, mackerel, etc., makes them
grow very rapidly, and those that ascend the
rivers as " grilse " the following year are often
more than double that length. Many of them,
however, spend two or three or more years in
the sea before they return, and these grow to
a great size. Some do not return at all, but
remain about the estuaries. It is unlikely that
those that do this ever breed ; spawning is
only known to take place in fresh water.

THE STORY OF THE LAMPREY

One of the most interesting animals that live
in fresh-running water is the lamprey. It is
not very easy to see, for most of its life is spent
concealed in the sand. But at the breeding
season it comes out of its hiding-place, and
begins to make preparations for the advent of
the next generation.

Let us look for a moment at the lamprey
itself. The common brook-lamprey is eel-like
in appearance, and, when full grown, is about
7 inches long. Its skeleton is gristly instead
of bony, like that of the true fishes. It has
two fins on the middle line of the back and a
tail-fin, but no paired fins. It has no jaws,

THE FRESH WATERS 173

but it has a round sucker-mouth, and a very
muscular tongue, covered with horny teeth.
With its sucker-mouth it fastens itself to the
body of a fish, and, protruding its rough tongue,
proceeds to rasp the flesh off its unfortunate
victim. Fishes have sometimes been seen to
turn over on their sides, so that the trouble-
some " boarder" is out of water, and is forced
to let go its hold.

Along each side of the body of the lamprey,
near the head, there are seven conspicuous
holes. These are the gill-slits, and the gills
to which they lead are continually washed by
water. In most fishes, water enters by the
mouth and flows out at the gill-slits, carrying
away the used air from the blood. But the
lamprey uses its mouth to fasten itself to its
prey, and, in its case, water flows in at the gill-
slits and out again.

The eyes are large, and there is a single
nostril, which lies right in the middle line of
the head so that, whichever side of the body
we look at, we see an eye and eight holes.
This is why lampreys are popularly called
" nine-eyes "or "niners."

As spawning-time approaches, the lampreys,
both male and female, set about preparing a

174 THE HAUNTS OF LIFE

safe place for the eggs. They choose out a
spot with a sandy bottom and, attaching them-
selves by their sucker-mouths to any stones
upon it, they pull these to the lower part of
their chosen site, thus making a little dam
which will keep the eggs from being washed
away. Then they fasten themselves to a stone
at the upper edge of their pool, and lash up
the sand with their tails, while some of the
eggs and sperms are discharged into the water.
The eggs sink to the bottom, and the sand
settles over them. More stones are added to
the wall of the dam, and the laying process is
repeated at intervals. Sometimes a number
of lampreys combine to make a nest, and they
may be seen hanging in a cluster from a stone.
When spawning is over, the lampreys are so
exhausted that they never recover ; they float
away downstream and soon die.

The eggs hatch out in about three weeks.
The young ones are quite different from their
parents, and got their common name of
" Prides " long before it was known what they
really were. They are yellowish, worm-like
creatures, with no visible eyes, and a horseshoe
mouth. They make a kind of tunnel open at
both ends in the sand, and spend all their time

THE FRESH WATERS 175

there, wriggling farther in when disturbed.
They take four years to reach their full size,
and then, within a few weeks, they undergo the
change to the adult form.

The River Lamprey, which is still abundant
in the Severn and some other English rivers,
grows larger, and usually spends a part of its life
in the sea. It used to be considered a table
delicacy, and it was from the effects of too hearty
a meal of these lampreys that Henry 1 1. is said to
have died. They are still caught in considerable
numbers, but are chiefly used for bait. There is
a still larger Sea Lamprey, that spawns in rivers.

FROM WATER TO LAND

We shall find an instance of animals that
seem to be on their way from fresh water to
terrestrial life in a very familiar group — the
frogs and toads, with their more distant cousins,
the newts and salamanders.

We need not go over the life-history of the
frogs and toads, because any of us can watch
it for ourselves, and it is very much better to
see things than to read about them if it is
possible. We have only to listen for the
croaking of the frogs in March or April, then

1 76 THE HAUNTS OF LIFE

look for the clumps of jelly-like eggs, take
them home and keep them in a properly shaded
vessel, and we can follow the whole fascinating
story. But we must be careful to keep water-
plants growing in our aquarium, that the water
may be aerated, to supply food, but to remove
all decaying matter, and to provide a foothold
for the little creatures when they are about to
make their great change from the tadpole to
the frog stage.

All the members of the group have in their
full-grown state the great characteristic of adult
terrestrial animals — they breathe, by means
of lungs, the oxygen in the air. But the young
of almost all of them have gills and breathe
the oxygen dissolved in water. The time the
tadpole breathes by gills may be longer in one
family than another, it may even vary in the
same family, according to surroundings and
weather, but, long or short, it is very rarely
omitted.

Another fact that shows the direction in
which they are tending is that even the adults
are not all equally terrestrial in habit. Both
frogs and toads spend some time in the water
in spring, and leave it when their eggs are
safely deposited. But as winter approaches,

THE FRESH WATERS 177

the toad buries itself among withered leaves,
or in some dry spot, while the frog returns to
the pond or ditch and hides itself in a hole,
perhaps in a drain-pipe, it may even be in the
damp mud.

But the frog has long ago lost its gills, and
its lungs are closed in winter by the shutting
of the nostrils. How then does it breathe, for
breathe it must, even though the fires of life
are very low ? The skin is exceedingly thin
and delicate, and there is a network of very
fine blood-vessels all over it, and the exchange
of gases — used carbonic acid gas for fresh
oxygen, which is the essential part of breathing
— takes place directly from these blood-vessels
through the skin.

WATER INSECTS

One more group we must think of for a
little — the aquatic insects.

All fully developed insects breathe air
through little openings on the surface leading
into fine tubes, called tracheae, which carry the
air to all parts of the body. Even insects
which spend their whole lives on and in the
water breathe in this way. They may be able

12

1 78 THE HAUNTS OF LIFE

to remain under water for considerable periods,
because they have various ways of carrying
reserves of air, as bubbles entangled among
the body-hairs, for instance, while others are
able to use the oxygen mixed with the
water.

In addition to these, many insects, such
as the gnats, may-flies, caddis-flies, and the
beautiful big dragon-flies, lay their eggs in the
water, and the great changes from egg to larva,
from larva to the " resting-stage," which is a
preparation for the emergence of the perfect
insect, are gone through in the water. Yet
this is not a case in which an aquatic race is
on the way to terrestrial life ; they are not
water-breathers, they are air-breathers, which
have adopted the habit of laying their eggs in
the water for the greater safety of the young.
Many of the larvae have become so well adapted
to aquatic life that they are able to breathe
dissolved air by gills, but these " tracheal gills,"
as they are called, are developed from the air-
tubes which are present, even though the
openings to them are closed. And many of
the larvae breathe surface air from the first.
The gnat larvae, which we may find in any ditch,
have a breathing-tube projecting from the last

THE FRESH WATERS 179

ring of their bodies, and may be seen hanging
head downwards from the surface so that air
may enter. There are other aquatic larvae
which never even get wet. This is difficult to
understand, because it requires a knowledge of
physical properties, but it is a fact, and it is illus-
trated in a very varied way among animals that
have gone back from the dry land to the water.
Some water-beetles can hardly become wet at
all ; some keep the greater part of the body dry,
but not it all ; some become quite wet. The
little whirligig beetle (Gyrinus) and the Water
Boatmen (Notonecta) become very slightly
wetted. The water-spider remains dry over
a considerable part of the hairy body.

The time spent in the water is often very
long compared with the aerial life. Some of
the caddis-flies are said to spend three years
in the water, and then only to live a few days.
And some aerial lives are shorter still. Some
of the May-flies or Ephemeridce, as they are
called, from the shortness of their lives, live
only a few hours as winged insects in the air.
But their larval life in the water lasts for two
or three years, during which they feed, grow,
and cast their husk many times. At length
there is the making of the wings and the

i8o THE HAUNTS OF LIFE

eventful emergence from the water. They
cannot fly much at first, for they are encumbered
by a thin veil too truly suggestive of a shroud.
They rest rather wearily on the branches of
the willows, and on our clothes, as we watch

FIG. 17. — GARDEN SPIDER (EPEIRA
DIADEMA).

them. We see them writhe and jerk, till at
length their last encumbrance, their " ghost,"
as some entomologists have called it, is thrown
off. Then the short aerial life begins ; they
swing to and fro as in a dance; they dimple

THE FRESH WATERS 181

the smooth surface of the water with a touch
into smiling ; we see them chasing, embracing,
separating. There is great beauty in their
film-like wings, in their large, lustrous eyes,
in the graceful sweep of the long tail-
filaments.

" They never pause to eat ; they could not
if they would. Hunger is past, love is just
begun, and in the near future is death. The
evening shadows grow longer — the shadow of
death is over the Ephemerides. The trout
jump at them, a few raindrops thin the throng,
the stream bears others away. The mothers
lay their eggs in the water, and, after doing so,
many seem utterly spent, and die forthwith.
The eggs, however, are in the water, and the
race continues."

THE STOR¥ OF THE FRESH-WATER
SPIDER

Before we leave the fresh waters, let us look
at the water-spider (Argyroneta natans), one
of the conquerors. It strikes the note of
adventure which is so characteristic of animals.
For while it is a land animal by nature and
origin, and breathes dry air, it has learned to

FIG. 18.— THE FEMALE FRESH-WATER SPIDER (ARGYRONETA NATANS).

It has made a Diving-bell-like Web, buoyed into a Dome with Air. Note Air

entangled on Spider's Body. Note special lines to- Surface.

THE FRESH WATERS 183

live underneath the water. It is the female
water-spider who is particularly admirable, so
we shall henceforth say "she." She spins a
flattish web beneath the water, and moors it with
silk threads like tent-ropes to stones and weeds.
A special line runs up to the surface and is fixed
to a floating plant. Up and down this rope the
spinner goes many times ; at the surface she
gets air entangled in the hairs of her body ; she
climbs down, looking like a drop of quicksilver
in the water — the air glistens so ; she brushes
her hair with her legs, and the air-bubbles are
caught underneath the web, which thus becomes
buoyed up like a dome or like an anticipation
of a diving-bell. After many journeys up and
down the web is full of dry air, and there the
spider deposits her eggs and rears her young.
Sometimes when she is in a hurry she gets into
the empty shell of a water-snail and manages,
we do not quite know how, to fill it with air
brought down from the surface. There are
many interesting facts about the water-spider,
for instance, how she arranges tags of silk
among her hair, which probably help in en-
tangling the air-bubbles. For reasons, rather
difficult to explain, she never gets wet. But
the big interest is just that this spider found an

1 84 THE HAUNTS OF LIFE

empty corner — an empty niche of opportunity
— full of difficulties, to be sure, but offering
new opportunities of food and safety. How
splendidly well has she overcome the difficulties
and used the opportunities.

CHAPTER V

THE CONQUEST OF THE DRY
LAND

Tell-tale Evidences of Marine Ancestry — Origin of Land Plants
— The Three Great Invasions of the Dry Land — New Ways
of Breathing — Changes in Movements — New Ways of
Looking after the Young — New Kinds of Protection —
Betwixt-and-Between Animals — Haunts within Haunts —
Beneath the Ground — Cave Animals — Arboreal Life.

OVER and over again in the history of
animal life some adventurous members
of aquatic races have become colonists of the
dry land. Perhaps we should not be quite
wrong if we said, a little fancifully, that one of
the great unspoken wishes of animals was to
get out of the water. In any case, it is almost
certain that the great majority of the different
classes of land animals had their ancestry in
the sea, some of them making the transition —
which might require millions of years — through
fresh waters.

We must be careful here to see the facts

clearly. Land mammals had their origin in

185

1 86 THE HAUNTS OF LIFE

land reptiles, and birds had their origin in land
reptiles — where then is the marine ancestry ?
But the reptiles sprang from an ancient am-
phibian stock, whose very name, amphibian,
suggests that they lived partly in water and
partly on land. And these amphibians sprang
from fishes, and the original fishes were in the
sea. So that when we say that the ancestors
of land animals were marine, we usually mean
their distant ancestors, belonging perhaps to a
much simpler class. On the other hand, when
we look at the terrestrial crustaceans, called
wood-lice or slaters, which we see running
about if we turn over loose stones or strip off
loose bark, we may safely say these are the
direct descendants of sea-slaters, such as we
find to-day among the rocks on the shore.

TELL-TALE EVIDENCES OF MARINE
ANCESTRY

It may be asked, however, why land animals
may not have begun their existence on land,
instead of being derived from distant ancestors
in the sea. This is a good question, which
requires a longer answer than is possible
here. But part of the answer is this. Land

THE CONQUEST OF THE DRY LAND 187

animals carry about in their bodies the tell-
tale evidences of a marine, or at least of an
aquatic, ancestry. Thus all the embryos of
reptiles, birds, and mammals have gill-clefts on
the sides of their neck, opening into the pharynx
(the beginning of the food-canal, just behind
the mouth), and in two or three cases, in reptile
and bird, tuft-like traces of the gills themselves
have been recently discovered. These gill-
clefts are of no use for breathing in reptiles,
birds, and mammals ; indeed, we cannot say that
they are of any use at all, except the first one,
which becomes a tube (the Eustachian tube,
named after an old anatomist) leading from the
ear-passage to the back of the mouth. But
these gill-clefts are always present, and they
must be regarded as historic relics. As Darwin
said, they are like unsounded letters in words,
which tell us part of the history of the word.
Thus the unsounded o in leopard tells us that
this animal used to be regarded as a cross be-
tween a lion and a tiger (or pard). So there
are vestiges in land animals which betray their
aquatic ancestry.

In the ear-passage of a mammal there is a
drum or tympanum stretched across just a little
way below the surface. On this drum the

1 88 THE HAUNTS OF LIFE

waves of sound strike ; this is the door at which
they knock. But the vibrations have to be
conveyed to the real ear — the delicate organ of
hearing — which is safely lodged in very dense
bone (periotic) deeper down in the skull. Now,
running from the drum of the ear to the inner
ear, there is, in mammals, a chain of three little
bones called the Hammer, the Anvil, and the
Stirrup (Malleus, Incus, and Stapes). What
do these turn out to be ? Their development
shows that they are just transformed pieces of
bone which, in fishes, form part of the common-
place framework of the jaws. This is another
tell-tale evidence of the very distant aquatic
ancestry of mammals.

Another very remarkable fact has to do with
the blood. Many of the lower animals, such as
sponges and jelly-fishes, sea-anemones and
corals, and the simpler worms, have no blood ;
but every one knows that this is very unusual.
From ringed worms to man, almost all animals
have blood, though, in many cases, like lobster
and snail, it is not very noticeable, being practi-
cally colourless. This blood is a very complex,
chemical mixture ; its watery basis contains
solutions of salts, sugar, proteins, and nitro-
genous waste-products. Every boy who has

THE CONQUEST OF THE DRY LAND 189

put his bleeding finger to his mouth knows that
the blood has a salt taste. And it is very
remarkable that the salts in the blood are in the
main the salts of the sea, and that they occur
in very much the same proportions as in
the sea. The correspondence becomes closer,
when we take into account the change in the
composition of the sea since blood was first
established millions and millions of years ago.
This tells a tale.

We cannot turn back the hands of the world-
clock, and get it to strike over again the hours
that are past, but there is the rock-record to
help us to get away from conjecture. And, as
we have just seen, some help is to be got from
the individual development which is, in some
measure, in the making of organs and the build-
ing up of the body, a recapitulation — much
condensed and telescoped — of the history of the
race.

We should also remember that some of the
changes we suppose to have occurred millions
of years ago have their counterparts in changes
that are taking place to-day. Evolution is not
something done with ; it is going on. Thus
the Robber-Crab is a shore-animal in process of
becoming terrestrial.

190 THE HAUNTS OF LIFE

There is another reason why it is not easy to
think of land animals beginning on the dry
land ; the conditions of life are too difficult for
beginners or apprentices. This will become
clearer later on, but it may be noticed that
breathing and moving, and the disposal of the
eggs or young, are much more difficult on land
than in the water. As it is much more difficult
to escape from enemies when movement is all
in one plane, we cannot wonder that many land
animals have become burrowers, and others
climbers, and others fliers, that others have
become camouflaged, and that others have taken
to coming out at night only. But we shall
return to this subject later on.

ORIGIN OF LAND PLANTS

When we consider the sand-dunes, the rocky
islands, the deserts, the mountain-tops, and so
on — we feel at once that there are many parts
of the dry land which cannot be called very
hospitable to living creatures. The dry land is
a haunt very much more difficult than the sea
or the lake. The fact is that no great colonisa-
tion by animals was possible until plants had
prepared the way. They provided food, shelter,

THE CONQUEST OF THE DRY LAND 191

and moisture. They were the pioneers for
animals, and the simpler plants likewise made
higher plants possible.

According to the rock-record, long ages
passed before land plants began. For while
there are fossil remains of seaweeds in very
ancient rocks, there is no definite evidence of
land plants till millions and millions of years
had passed. It was not till ages after that
(early Tertiary) that grass began to cover the
earth like a garment — an event with far-reach-
ing consequences.

As to the origin of land plants, there are two
theories. It is possible that very simple plants
migrated from the sea to the fresh waters, and
thence to swampy ground ; and that a fresh
start was made there which gradually led to a
land vegetation. But one of the most thought-
ful botanists of to-day, Prof. A. H. Church, has
recently argued that the highly developed shore
vegetation of seaweeds may have given origin
to the dry-land plants by gradual transformation.
There is no doubt that the seaweeds have
attained great complexity of structure, and it
may be that instead of representing a gorgeous
blind alley, they point the way to higher plants.
If the coast was slowly raised, as it often was,

192 THE HAUNTS OF LIFE

the great seaweeds might be gradually trans-
formed into terrestrial plants. Who knows ?

THE THREE GREAT INVASIONS OF THE
DRY LAND

In the conquest of the dry land we can dis-
tinguish three great invasions or colonisations.
The first was the Worm- Invasion, led by simple
worms such as the land-planarians, which had
begun the profitable habit of moving with one
end of the body always in front. In marine
animals of comparatively low degree, such as
jelly-fishes and swimming-bells, sea-anemones
and corals, the symmetry of the body is more
or less radial, that is to say, there is no right
or left, no head- or tail-end. The body can be
cut into two almost identical halves along many
different planes. Radial symmetry may be
illustrated by an orange and by the circular
plate it rests on. It is well suited for easy-
going life, for drifting in the sea, or for waiting
for food to drop into the mouth. But certain
worms acquired bilateral symmetry, moving
with one end of the body always in front.
This was better suited for quick and definite
movements, such as are needed in the pursuit

THE CONQUEST OF THE DRY LAND 193

of prey or the avoidance of enemies. And as
the acquisition of bilateral symmetry was associ-
ated with the acquisition of head-brains, we may
say that it was the beginning of our knowing
our right hand from our left. In any case,
radial symmetry is out of the question on dry
land, and the first colonisation was attempted
by simple bilateral worms.

The most important members of the "worm-
invasion " were the earthworms, which probably
evolved from a fresh-water stock. This is sug-
gested by earthworms like Alma and Dero,
which have gills, and there are many not very
distant relatives of earthworms now at home in
fresh water, such as Nais and Tubifex, common
in streams. The importance of earthworms in
the conquest of the dry land is well known, for
they have made the fertile soil of the globe.
Their successful possession of the subterranean
world at an early date implies the previous
establishment of some terrestrial vegetation, for
earthworms depend for food on the plant
remains in the earth, which they swallow, and
on such fragments as they are able to capture
on the surface.

We know that earthworms have been land
animals from very early times, for, though no
13

194 THE HAUNTS OF LIFE

actual fossils have been found, as they have no
hard parts which could have been preserved,
yet we have evidence of the existence of worms
in the remote past " by the discovery of the
trails which they have left in crawling over soft
mud, now hardened into shale or slate, or by
the burrows which they made in sand, which
has now been converted into sandstone and
quartzite. . . ." "Worm -burrows and trails
are among the oldest fossils yet discovered."

FIG. 19.— PERIPATUS.
A primitive Air-breather, antecedent to Centipedes and the like.

The second great invasion was that of the
Air- Breathing Arthropods, led by simple
jointed-footed animals, well represented by a
" living fossil," called Peripatus, an old-fashioned
creature, surviving from a very different world.
Peripatus is a beautifully coloured soft-bodied
animal, worm-like in shape, but with simple
stumpy limbs, with antennae on the head, and
two pairs of mouth-parts. It lives chiefly in
rotting wood, and comes out only at night.
When it is handled it squirts out from mouth-

THE CONQUEST OF THE DRY LAND 195

papillae tiny jets of slime, and it is believed to
do this also as a means of catching small insects.
Peripatus is of great interest to naturalists,
because in some important respects it resembles
a worm, while, in others, especially in the posses-
sion of breathing-tubes, it has risen to a higher
level, and shows relationship with insects. It
must be very well adapted to its mode of life,
for it is very widespread in warm countries,
being found, with slight differences between

FIG. 20.— A CENTIPEDE.

the species, in Central America, the West
Indies, in Chili, in New Zealand and Australia,
in Asia, in Central Africa, and at the Cape of
Good Hope.

The second great invasion led on to centi-
pedes, millipedes, insects, and spiders, and just
as the worm-invasion resulted in the making of
fertile soil, so the second invasion had for its
great consequence the establishing of a linkage
between flowering plants and the flower-visiting

196 THE HAUNTS OF LIFE

insects, which carry the fertilising golden dust
or pollen from blossom to blossom. This is
certainly one of the most important linkages in
the world.

Darwin's " Cats and Clover" Story. — In his
immortal book, The Origin of Species (1859),
Charles Darwin told the story of the connection
between cats and clover — a story that soon
went round the world. It is a very familiar
story, but it should not become trite to us, for it
was the first vivid story of its kind, and it was
told by the greatest of all naturalists.

Darwin took one hundred heads of the big
purple clover and put muslin bags round them,
so that the air and the sunshine could get in,
but no humble-bees, which he knew to be the
usual visitors of the clover. From these plants
he got not a single seed, while from another
hundred heads close by, to which the bees had
access, he got 27,000 seeds. The fertilising
dust or pollen which the bees carry from one
clover blossom to another makes the possible
seeds into real seeds, that is to say, embryo
plants. A nucleus from the pollen-grain, which
grows down the pistil of the flower to the
ovules, fertilises an egg-cell inside the ovule,
and as this develops into an embryo-plant, the

THE CONQUEST OF THE DRY LAND 197

possible seed or ovule becomes a real seed, which
will grow into a plant when it is sown. So the
more humble-bees, the better next year's clover
crop.

But the nests of the humble-bees, which are
hidden in the ground or in a mossy bank, are
often burglared by the field-mice or voles, which
devour the white grubs of the bees. So the
more field-mice, the fewer humble-bees.

But the cats on the prowl kill the field-mice,
which are therefore scarcer near villages than
in the open country. The cats do not appear
to eat the field-mice, but they kill them for
sport. So the more cats, the fewer field-
mice.

One may perhaps go a step further and say !
The more kindly ladies in the village, the more
cats there will be ; and the more cats, the fewer
field-mice ; and the fewer field-mice, the more
humble-bees ; and the more humble-bees, the
better next year's clover crop.

In any case, we must understand that the
pollination or fertilisation of flowers by their
insect-visitors, a linkage established after the
second great invasion, is one of the most
important linkages in the web of life. For the
fertilising dust or pollen is necessary if the

198 THE HAUNTS OF LIFE

possible seeds are to become real seeds which
will sprout. And even when the pollen can
pass from the stamens of the flower to the pistil
of the same flower (self-pollination), the results
are not usually so good as when the pollen is
carried by insects (or by the wind) from one
blossom to another. When there is cross-
fertilisation the yield of seeds is better. And
the plants so produced tend to be more variable,
which will be a good thing if it is useful for the
plant to change.

The Third Great Invasion. — It was about
the end of the time known as the Devonian or
Old Red Sandstone that amphibians made their
appearance, and, in the next age, the Carboni-
ferous, when the coal measures were laid down,
they had their golden age. These early amphib-
ians, ancestors of our frogs and toads, newts
and salamanders, were the advance guard of
the third great invasion, which eventually led
to the appearance of reptiles, birds, and
mammals. This third invasion meant the
opening up of many new possibilities for
animals, and, in the long run, it led to
man.

It is interesting to notice some of the new
things that began with amphibians, the advance

THE CONQUEST OF THE DRY LAND 199

guard of the third great invasion. They were
the first animals to have fingers and toes (the
paired fins of fishes are limbs, but they have no
digits), the first animals to have a three-
chambered heart (though the mud-fishes come
near this), the first animals to have true lungs
(though some fishes like the mud-fishes use
their swim-bladder to help them in breathing,
and it is no doubt the forerunner of a lung),
the first animals to have a movable tongue, and
the first backboned animals to break the silence
of animate nature by having a voice.

Besides the three invasions or colonisations
which we have mentioned, there were no doubt
others, like that which led to land-crabs and
wood - lice (terrestrial crustaceans), or that
which led to snails and slugs (terrestrial
molluscs).

But in thinking of the conquest of the land,
we will not go far wrong if we give prominence
to the idea of three great invasions — the first,
the worm invasion, leading to the making of
fertile soil ; the second, the insect invasion,
leading to the linkage between flowers and
their visitors ; the third, the amphibian in-
vasion, leading to the evolution of wits and of
love.

200 THE HAUNTS OF LIFE

NEW WAYS OF BREATHING

The colonisation of the dry land by aquatic
animals cannot have been an easy task, and
our question now is : What were the necessary
qualifications ?

The first qualification was ability to capture
the oxygen of the dry air. There is a much
larger proportion of oxygen in the air than there
is mixed with the water, but it is not so readily
available. For, mixed with the water, it seems to
seep in very readily through the delicate moist
skin of the general surface of the body, or of
special organs, such as gills. On one side of the
membrane there is water, with oxygen mixed
in it ; on the other side of the membrane there
is blood, which usually carries a pigment with
a strong affinity for oxygen. What happens in
aquatic breathing is that the oxygen diffuses
through the skin into the blood, usually entering
into a loose, chemical union with the blood-
pigment. With its captured oxygen the blood
passes to the living tissues of the animal, to the
muscles, for instance, and there surrenders its
oxygen to keep up the ceaseless burning (or
oxidation) which living implies. As the result
of the combustion (or oxidation) of complex

THE CONQUEST OF THE DRY LAND 201

carbon-compounds in the tissues, the waste gas
CO2 (carbonic acid or carbon dioxide) is formed,
which is collected by the blood, and got rid of

202 THE HAUNTS OF LIFE

on the skin or on the gills, if there are gills.
An animal like a leech is a good example of
cutaneous respiration, simply through the skin ;
a lobworm or a lobster, a mussel or a fish, may
illustrate respiration by gills.

But getting on to dry land involved dry
skins and protected skins, and the diffusing-in
of oxygen was no longer so easy. Thus we
find various devices for getting the air into the
interior of the body and for spreading out the
blood on internal, not external, surfaces. Thus
insects evolved air-tubes, carrying fresh air to
every hole and corner of the body — surely part
of the secret of their great activity — and amphib-
ians evolved lungs, probably transformations of
the swim-bladder of fishes.

The lowest animals to show the red-blood-
pigment (kcemoglobin), which we and all back-
boned animals have, were certain worms called
Ribbon- Worms or Nemertines, which live for
the most part on the seashore. The virtue of
this haemoglobin is that it captures oxygen very
readily from outside, and parts with it readily to
the living tissues, and it is certainly interesting
that some of the Ribbon-Worms have become
terrestrial. There are many backboneless
animals, such as most of the Arthropods and

THE CONQUEST OF THE DRY LAND 203

Molluscs, that have no haemoglobin, but some
other blood-pigment (e.g. haemocyanin) not quite
so good. Yet we may be sure that the secret of
making haemoglobin was never lost. It was too
good to lose. If haemoglobin was not always
continued along the main line, where haemocy-
anin often took its place, it was continued on
side-lines of descent ; and all backboned animals
have red blood. A pretty case, illustrating the
value of the red-blood-pigment, is that of the
"blood- worms," which are sometimes to be found
in rain-water barrels and in stagnant pools, where
the oxygen in the water is very scarce. These
" blood-worms " are the aquatic larvae of certain
Harlequin-flies (Chironomus) ; they are called
" blood- worms," because they are so red ; the
redness is due to haemoglobin, which few insects
have ; the haemoglobin is present in " blood-
worms," because they live in situations where
oxygen is very scarce, where haemocyanin is
hardly good enough. More strictly, perhaps,
we should say that Harlequin-flies are insects
with red blood, and that this makes it
possible for their larvae to live in very foul
water.

The land animals' new way of breathing
notably by means of internal surfaces, like the

204 THE HAUNTS OF LIFE

breathing chambers of land-snails, where the
blood is spread out on the roof of a cavity
containing air, or the true lungs of amphibians
and higher vertebrates, should be thought of in
connection with the fact that land animals tend
to become thick-skinned, or to acquire some sort
of protection over their skin. An earthworm is
still tender-skinned, and it breathes by its skin ;
a frog is still tender-skinned, and it breathes
partly by its skin all through its life, and wholly
by its skin in winter. But in the scaly reptiles,
in the feathered birds, and in the thick-skinned
mammals, usually well-protected besides, all
trace of skin-breathing (or cutaneous respira-
tion) has vanished.

CHANGES IN MOVEMENTS

Animals in the water have the great advan-
tage of universal freedom of movement in any
direction. They can go up or down, forward
or backward, to right or to left, in any and every
plane. But land animals can move only in one
plane — on the surface of the earth; and this
means very great limitations and a great in-
crease of risks. It is more than ever necessary
that the movements should be quick and precise ;

THE CONQUEST OF THE DRY LAND 205

fumbling and stumbling are fatal. But improve-
ment of movements means a more complicated
muscular equipment and a more effective con-
trolling (or nervous) system. It is fair to say
that the brain was the controller of movements
long before it was a thinking organ.

We do not mean that the movements of
aquatic animals are not admirable. The swim-
ming fish or squid cannot be surpassed. We
mean that the freedom of movement in the
water allows a certain leisureliness (in jelly-
fishes, for instance) which is impossible on land,
unless there is some compensating peculiarity,
such as coming out at night. No animal moves
at random, but the water animal has a wider
range of alternatives than a land animal. And
it is not only that land animals are confined to
one plane, unless they learn to burrow, or climb,
or fly, they have to follow their food with a new
strenuousness. In the open sea, the deep sea,
and the fresh waters, and, to some extent, on the
shore, food is sometimes brought to the hungry
animal, but it is very seldom that this can be
said to occur on land.

It must be noted, however, that an apprentice-
ship to quick, precise movements, such as land
animals require, was probably served on the

206 THE HAUNTS OF LIFE

shore, for the conditions of life are more than
half terrestrial when the tide is out.

In his fine introduction to Zoology, called
Animal Life, Professor F. W. Gamble gives a
vivid picture of the four chief kinds of animal
locomotion. He takes the case of a man in a
boat on a river, who can make headway against
the current in four ways, (i) He may take a
boat-hook and, fastening it to the roots on the

FIG. 22.— A JERBOA.
A leaping Biped belonging to the Rodent Order.

bank, pull himself forward. So does a star-fish
pull itself up a rock ; so does a leech pull itself
forward when it fixes its mouth. This is the
pulling method. (2) He may take a pole, or
an oar for that matter, and, pressing it against
the bed of the stream, lever himself forward.
So does the beetle push its legs against the
ground ; so does the crab on the shore lever

THE CONQUEST OF THE DRY LAND 207

itself along ; so do we when we walk. This is
the punting method. (3) He may take an oar,
and, going to the stern of the boat, he may
press the water from side to side, displacing
masses of water in a regular rhythm. So does
the fish grip the water with the posterior part
of its body, popularly called the tail, and thrust
the water away from it, first to one side and
then to the other. So does the whale with its
propeller-like tail — a propeller, however, that
does not go round. This is the sculling method.
(4) Or the man may sit down on the seat of
the boat and take up the oars and row. The
insect called the Water-Boatman rows on the
water with its third pair of legs ; the turtle rows
with its flipper-like limbs, and the penguin with
its flightless wings and with its feet as well.
Aquatic birds, when swimming, row with their
feet ; some diving birds row under water with
their wings. Flying birds row in the air with
their wings.

Now it may be said that the conquest of the
dry land meant, among other things, that the
punting kind of locomotion became very im-
portant. It was learned on the shore ; it was
perfected on dry land. Even the snake, which

208

THE HAUNTS OF LIFE

is often described as rowing upon the ground
with every rib for an oar, is perhaps, more

FIG. 23. — THE AUSTRALIAN COLLARED LIZARD (CHLAMYDOSAURUS).

It is at present trying to be a Biped. When it stands at bay, it expands
its Collar. When it runs, it folds its Collar back on its Neck. (After
Saville Kent.)

accurately, described as punting with many
poles.

THE CONQUEST OF THE DRY LAND 209

Except in the case of some sprawling
creatures, like centipedes and snakes, the body
of a land animal tends to be compact. The
weight has usually to be lifted and supported
off the ground, whereas in an aquatic animal
the weight is supported in the water. An
animal like a jelly-fish is unthinkable on land.

NEW WAYS OF LOOKING AFTER THE
YOUNG

The conquest of the land necessarily means
new ways of looking after the eggs or the
offspring. For the aquatic animal, it is often
enough simply to liberate the eggs into the
water, which serves as their soft cradle ; but it
would be fatal in most cases if a land animal
merely laid its eggs or its young ones on the
ground. They would be dried up or devoured.
So we find many ways in which safety is
secured, e.g. by burying the eggs in under-
ground nests ; or by keeping the young ones
within the mother's body for a long time before
birth, so that they are not very helpless when
born ; or by carrying them about after birth, as
in kangaroos and opossums.

One of the ways of securing the safety of
14

210 THE HAUNTS OF LIFE

the eggs or the young ones is to put them all
in a hole in the ground. Earthworms make
a little barrel of hardened slime secreted by the
" saddle" or swollen girdle on their body, and
as this slips forward it carries the liberated
eggs with it and closes up at the ends. We
find it sometimes when digging in the garden.
The mother trap-door spider makes a well-
finished shaft with smooth walls and a silk-
hinged lid, and lays her eggs in a bunch at the
foot. The crocodile lays her eggs in the warm
earth, sometimes with decaying vegetable matter
round about, and the young one calls to her
from within the egg when it is ready to be
hatched, for it would be awkward to be born
2 feet below the surface. Yet that is what
happens to the offspring of those mound-birds
that dig a hole in the warm, loose volcanic sand
of the beech in Celebes. The mole's nest is
also underground — a grass-lined chamber below
a big mole-hill.

Another way of securing the safety of the
eggs or the offspring is to hide them off the
ground altogether. Many insects lay their
eggs in or on leaves ; many spiders put their
eggs in a silken bag or cocoon and fasten this
between two leaves, or in a crevice. Some

THE CONQUEST OF THE DRY LAND 211

tree-toads lay their eggs in a damp hole in a
tree, and one of them makes a leaf-nest on
branches overhanging the water, and arranges
matters so that the bottom falls out and lands
the contents in the water just as the eggs
are turning into tadpoles. The harvest-mouse
fastens to the wheat stems its lightly built nest
of twined leaves of grass. We must not include
the nests of animals like squirrels, which have

FIG. 24. — THE AUSTRALIAN DUCKMOLE (ORNITHORHYNCHUS).

An old-fashioned Mammal that lays two eggs in a well-hidden

nest in a Burrow beside a Pool.

ceased to be terrestrial in the strict sense, or
the nest of flying birds and thoroughly aerial
insects like wasps.

A third way of securing the safety of the
young ones is to keep them for a long time
within the shelter of the mother's body, and
perhaps to carry them about after they are

212 THE HAUNTS OF LIFE

born. Thus the old-fashioned Peripatus, which
we have already spoken of, carries its young
one for a year before it is born. This means
that the young Peripatus is able to creep about
soon after its birth ; it hides itself under the
mother's body and, after a while, under bark.
Just in the same way among wild horses, which
must always be on the move, the foal is carried
by its mother eleven months before birth, and
the result is that when it is born it is not help-
less like a calf (which is hidden in a thicket),
but is able very soon to stagger along beside
its mother.

Among aquatic animals there is in many
cases a long larval life ; among terrestrial
animals the young are often born as miniature
copies of their parents from the first. This is
so even when a land animal is quite closely
related to one which brings forth its young in
the water. We saw that the young mountain-
salamander, which has no water stage, because
the streams are too swift, is born like its parent,
while its near relative, the fire-salamander of
the plains, which goes through the early stages
of its life in the water, begins as a tadpole, and
passes through several changes before attaining
the adult form.

THE CONQUEST OF THE DRY LAND 213

With the increasing need for protecting the
young there has grown up an increasing degree,
not only of parental care, but of parental
affection. The highest expression of this is
found — if we leave the birds out of account
— among the Mammals, that great class
which includes forms so different as Man, the
monkeys, the carnivores, the hoofed animals,
the gnawers, besides the aerial bats and the
marine whales. All these animals have one
great point of resemblance to which they owe
their name of Mammal — the young are fed
for the first period of their lives on the milk of
the mother. The period of suckling varies
greatly in length. The little harvest-mouse,
the smallest but one of our four-footed beasts,
makes an egg-shaped nest by splitting stalks
of grass or corn and weaving them firmly
together. The nest, which usually hangs from
a corn-stalk, is lined with soft leaves, and in
this comfortable home the young ones, eight
or nine at a birth, are brought forth, and are
suckled by the mother. But she only allows
them this luxurious life for a week or two till
they are able to see and to stand on their own
legs. Then, we are told, she takes them out,
"gives them a little practical instruction in the

214 THE HAUNTS OF LIFE

art of living, and hard-heartedly drives them
away." As she will have four or five more
litters, all equally large, before the summer is
over, we can easily understand that she has not
much time to spend over the nursing and
education of each set of babies.

In many of the larger mammals the time the
young take to develop within the mother and
the time of their helplessness after birth are
very long, and it is among these that we find
parental affection at its best. It is not merely
mother-love — the mouse has that, though only
for a short time. Both parents show affection
for their children, and their common care for
them has often led to lasting affection for each
other. The lion hunts along with his mate
during the breeding-season, but, as soon as she
becomes unable to accompany him, he hunts for
her, bringing his kill to the den, and letting
her satisfy her hunger before he takes his own
meal. From the time the cubs are weaned
until they are able to hunt for themselves he
kills for them too, and when they are able to
go out, which is not till they are almost a year
old, both parents go with them to teach them
their business in life. Both, but especially the
lioness, will defend the cubs fiercely from any

THE CONQUEST OF THE DRY LAND 215

danger, and at this stage they are terribly
destructive, for they kill anything and every-
thing that they find, whether they need food or
not, and this is apparently done to excite the
cubs so that they may become mighty hunters
in their turn. The cubs remain with their
parents till their third year, when they leave
the den, but they do not reach their full growth
and strength till they are about eight years old.

When parental care grew strong it became
unnecessary to have the multitude of offspring
produced, for instance, by fishes, which may
liberate millions of eggs. For the growth of
parental care secured the continuance of the
race with comparatively few offspring. But as
the number of children decreased it became
possible for the mother to know them all, to see
more of them, and to have them longer with her,
and all this meant more love. And more love
meant more care. So things work round in a
beautiful circle.

Perhaps this argument may seem very
difficult, but it is very important. Let us think
it over again. When it became possible for
animals to take great care of their children, it
also became possible to have quite small families
without there being any risk of the race losing

216 THE HAUNTS OF LIFE

its place in the sun. The cod-fish has its
two million eggs, and there is terrific infantile
mortality ; the golden eagle has usually two
eggs at a time, and the eaglets get a good start
in life. And when the family was small and
the parental care subtle, the parents that were
at once good and clever would be most success-
ful. A race with selfish and stupid parents
would tend to be wiped out.

NEW KINDS OF PROTECTION. — There is
another character which is absolutely necessary
to terrestrial life. Land animals must be able
to endure, or to accommodate themselves in
some way or other, to considerable differences
of temperature — between sunlit days and chilly
nights, between hot summers and cold winters.
We ourselves have this difficulty to face, and
we solve it by wearing heavier or lighter cloth-
ing, and by heating or shading our houses
according to the weather. But we are alone
in doing this ; Nature has found different
answers to the puzzle for others of her children.

A great many animals which find abundant
food in summer grow very fat in autumn, and
this coat of fat serves as a protection against
cold and against scarcity during the severer
months. The coats of fur-bearing animals

THE CONQUEST OF THE DRY LAND 217

become longer and thicker at the beginning of
winter, and the hairs fall out again in spring.
The same kind of animal may have a thicker
or a thinner coat according to the temperature
of the region in which it lives. The tiger, for
instance, is perhaps commonest in the hot
jungles of India, but the same species spreads
far north to very high-lying and very cold
regions, and tigers living in the north have
much thicker and longer-haired coats than those
in the south.

A very effective way of meeting the dangers
of a cold winter after a warm summer is to
avoid them by going to sleep. This is called
hibernating, and there are many degrees of it.
The squirrel, the dormouse, the marmot, and
many others fall into a light slumber in their
nests beside the heap of nuts and fruits they
have laid in, but they wake up and have a meal,
and even gather in a few more stores whenever
the sun is bright and the day warm.

We may take as an example of the heavy
sleepers our common British hedgehog. When
winter approaches he chooses a hole in an old
wall, or under a hedge, or among tree roots,
fills it with withered leaves, buries himself
among these, rolls up into a tight ball, and goes

218 THE HAUNTS OF LIFE

to sleep for the whole winter. He takes no
food all that time, but he is not moving, his
breathing is very slow, and his heart beats very
slowly and feebly, so he is not spending much
energy. Life is at a very low ebb, and what
waste there is, for there can be no life without
some waste, is made good at the expense of the
coat of fat he put on in autumn. Not much
fresh air gets into his hiding-place, so the

FIG. 25. — SPINY ANT-EATER (ECHIDNA).
A primitive egg-laying Mammal. The egg is placed in a skin-
pocket, where it develops. The Spiny Ant-eater illustrates
winter sleep.

carbonic acid gas given off by his feeble breath-
ing hangs like a poison cloud all round him and
helps to keep him in his heavy stupor. An
animal in this state has often been compared to
a fire which has been well built and then banked
up and allowed to become choked with its own
ashes. Hardly any heat is given off, but as
long as a red glow remains in the centre of the

THE CONQUEST OF THE DRY LAND 219

heap we can revive the fire by stirring it up to
admit air. When we have added fresh fuel
and cleared away the ashes it will burn as
brightly as ever again. So with the winter
sleeper. When the first warm breath of spring
penetrates into the hedgehog's hole, he gradually
awakens, stretches his stiffened limbs, and creeps
forth with a new lease of life. His breathing
quickens as his lungs fill with air, oxygen is
carried to every part of his body, the heart
beats more strongly and rapidly, and the now
hungry hedgehog begins to search eagerly for
the insects and worms on which he feeds.

If we stir up our resting fire too suddenly
and let in too much air at once the glow will
die out, and no amount of fresh fuel will re-
kindle the heap without fresh fire. Something
similar sometimes happens to the lighter sleepers
if they have been roused by a spell of mild
weather, and a hard frost sets in so suddenly
that they are nipped by it before they have had
time to settle down to sleep again. But, on the
whole, hibernation is a very successful device
for withstanding great changes of temperature.

Another way of meeting the winter is by
putting on a white dress. The ptarmigan,
which is rather grouse-like in summer, with a

220 THE HAUNTS OF LIFE

suit of grey and brown, puts on a white
plumage when the winter sets in ; and the
chestnut-brown stoat becomes the white ermine
— snow-white all over save the black tip of the
tail. Now this white dress gives its possessor
a garment of invisibility against a background
of snow, enabling it to slink upon its victims
and to elude its enemies. But there is some-
thing more — perhaps more important. For a
warm-blooded animal in very cold surroundings
the dress that loses least of the precious " animal
heat " of the body — the heat that makes it easier
for the chemical process of the body to go on
— is: a white dress.

We must not follow this subject further, but
it is interesting to think out some of the other
ways in which land animals meet the difficulties
of the winter. What are the expedients adopted
by moles, by harvest-mice, by the mountain hare,
by squirrels, by the curlews on the moor, by the
slow-worms, by the frogs ?

BETWIXT-AND-BETWEEN ANIMALS

Of great interest are the betwixt-and-between
animals, at present making the transition
between water and dry land. On many tropical

THE CONQUEST OF THE DRY LAND 221

shores there is a quaint fish called Peri-
ophthalmus, with protruding, very mobile eyes.
At low tide it skips about among the rocks,
hunting small animals, even catching insects.
As it clambers on to the exposed, bent-knee-like
roots of the mangrove trees, it may be spoken
of as a fish that climbs trees.

There is another tropical fish, known as the
Climbing Perch, which has the curious habit
of scrambling, by means of its very muscular
pectoral fins, up stones, roots, and even the
trunks of trees, in search of the insects, grubs,
and soft-bodied animals on which it feeds.

Still more surprising is the habit of a South
African fish, called Clarias, which is said to
make nocturnal raids on the fields in order to
eat the grains of millet. This fish lives in
districts where the rainy season lasts for only
two months in the year. The pools that are
filled with rain dry up very quickly in the heat
of the sun, and all the rest of the year the fish
lives its unfishlike life, hiding in damp burrows
through the day, torpid during the very hot
season, but in cooler weather coming out on
foraging expeditions at night. Some naturalists
declare that when this fish is frightened it
" screams like an angry cat," but, as no fish has

222

THE HAUNTS OF LIFE

THE CONQUEST OF THE DRY LAND 223

true vocal organs, the " scream," like the fainter
"cry" of our own bullhead, is probably the
sound made by the escape of air from its body.
For both Clarias and the Climbing Perch have
a special arrangement, a system of tubes branch-
ing from the gill-chambers, in which air is stored,
so that the fish is not altogether dependent on
its gills.

Land-crabs illustrate terrestrial animals in
the making. In warm lands, such as Jamaica,
there are many kinds, often living in forests far
from the sea, sometimes doing great damage in
the sugar plantations. But once a year they
assemble in enormous numbers to make an
excursion to the seashore and deposit their
eggs below high-water mark, where they leave
them to be swept out to sea by the tide. Then
they return, weary and spent, to their inland
haunt for the rest of the year.

Darwin, in his Naturalist's Voyage Round
the World, gives an account of the great Robber-
Crab which occurs in the Pacific Islands,
wherever the coco-nut palm grows. This
crab belongs to the same group as the hermit-
crab of the seashore, but it lives in a burrow
in the ground, and it lines it with the fibres from
the outside of the coco-nut shell. The Robber

224

THE HAUNTS OF LIFE

FIG. 27. — THE ROBBER-CRAB (BIRGUS LATRO).
Notice one climbing up a Coco-palm,

THE CONQUEST OF THE DRY LAND 225

grows to an enormous size, being sometimes a
foot in length, and, as it feeds entirely on the
pulp and milk of the coco-nut, its flesh is sweet
and oily, so it is regarded as a dainty by the
natives of the islands. Darwin believed that
the Robber-Crab only picked up the fallen nuts
from the ground, though it was known to climb
trees, but a later observer has not only seen but
photographed it in the act of picking the fruit
from the tree. To open the nut " the crab
begins by tearing the husk, fibre by fibre, and
always beginning from that end under which
the three eyeholes are situated ; when this is
completed the crab commences hammering with
its heavy claws on one of the eyeholes till an
opening is made. Then, turning round its
body, by the aid of its posterior and narrow pair
of pincers, it extracts the white albuminous
substance."

The Robber-Crab still has small gills, but its
gill-chamber is divided into two parts, and the
upper part is able to breathe dry air. Yet the
Robber-Crab is said to go to the sea at inter-
vals to moisten his gills. The young ones start
life in the water very much like young hermit-
crabs, but they reach maturity by a less round-
about path.
15

226 THE HAUNTS OF LIFE

HAUNTS WITHIN HAUNTS

Until an animal becomes big-brained and
resourceful, or is endowed with a rich equip-
ment of inborn gifts which we call instincts,
or has some special ways of protecting itself
or effacing itself, the surface of the earth is a
hazardous home. This makes it easy to under-
stand why there should be haunts within
haunts, such as caves and grottos ; why some
land animals become subterranean burrowers
and others arboreal climbers ; why some have
returned to the water, like the water-beetles
and the whales ; and why some have sneaked
inside other animals.

BENEATH THE GROUND

Among the first animals to discover the
world beneath the ground were the earthworms.
The strong probability is that they originally
belonged to a fresh-water stock, for several
earthworms have gills. When they colonised
the dry land and became able to breathe dry
air through their moist skin, they must have
had for a time a Golden Age. Land vegeta-
tion had been established, and they found food

THE CONQUEST OF THE DRY LAND 227

enough by eating the soil for the sake of the
plant remains in it, and by collecting plant
crumbs on the surface. The more they
worked, age after age, the more soil they
made, and the more plants there were with
crumbs to eat. In their newly discovered

FIG. 28.— DIAGRAM OF SOME BURROWERS.

An Earthworm to the right, a Mole-cricket to the left, a Mole

in the middle.

country below the ground the earthworms
lived, if not in ease, at least in safety. Mean-
while, however, evolution was in progress.
The second great invasion of the dry land had
occurred, which led on to creatures like centi-
pedes and burrowing, carnivorous beetles, both

228 THE HAUNTS OF LIFE

of which began to trouble the earthworms in
their retreats. Ages and ages passed and the
third great invasion occurred, which led on to
creatures like burrowing blind-worms, burrow-
ing slow-worms, and, long afterwards, burrow-
ing moles. And so, to cut a long story short,
the earthworms which once were so safe,
having discovered a new haunt, are among the
most persecuted of animals. So they have
become nocturnal.

When one begins to count up, one finds that
the number of subterranean animals is much
larger than one at first supposed. Mr. Edmund
Blunden had a fine vision of them when he
wrote his " Gods of the Earth Beneath" (The
Waggoner, and other Poems, 1920).

" I am the god of things that burrow and creep,
Slow-worms and glow-worms, mould-warps working late
Emmets and lizards, hollow-haunting toads,
Adders and effets, ground-wasps ravenous :
After his kind the weasel does me homage,
And even surly badger and brown fox
Are faithful in a thousand things to me."

CAVE ANIMALS

The animals that live below the ground are
mostly of a strenuous nature. The mole, for

. * %

* 3 S

111

S5 '

W

*z

o •

0 -3 O

1J!

*4 rt >
M « O-

W -5 "J

j •£ «*

PH X. g*

(U ^.

2

1
£

cc.

.-§

1H

w

THE CONQUEST OF THE DRY LAND 229

instance, is one of the strongest of all animals.
But it is quite different with most of the
animals that have found their home in caves.
Many of them are infirm, many are weak-eyed,
many are nervous and delicate. While we
admit that some of the cave animals may
have degenerated because they have lived so
long in caves, there is much to be said for the
view that most of the cave animals took to the
caves because they were weakly. This is borne
out by the study of animals that have recently
become cave-dwellers.

ARBOREAL LIFE

Animals owe a great deal to plants. In the
long run they depend on plants for food ;
animals use the munitions which plants manu-
facture. Plants prepared the earth for animals,
making it friendly ; they helped to secure
moisture and soft hiding-places. They formed
a subtle sieve against which animal life has
often beat, with the best of results. But one
of their crowning benefits was in providing
animals with trees to climb on. We some-
times use the phrase, "up a tree," to suggest
that a man is in a difficult and dangerous

230 THE HAUNTS OF LIFE

situation, but, as a matter of fact, getting up a
tree has often meant a progressive step in the
history of animal life. It opens up new
possibilities of movement, of feeding, of nesting,
and so forth, and it is a portal which many
different kinds of animals have tried to enter.
Even earthworms have been found up trees,
and the land-leeches often drop from the
branches. Many insects and spiders are
arboreal, and the Robber-Crab climbs the
coco-palm for nuts. The skip-jack, Perioph-
thalmus, climbs on the roots of the mangroves,
and there are many tree-toads. Among reptiles
there are arboreal lizards like the chamaeleon,
so admirably suited to the branches in having a
prehensile tail and both its hands and its feet
cleft into two halves for gripping purposes.
Then there are green and agile tree-snakes.
Many birds and mammals are strictly arboreal,
and, in the case of monkeys, the perfecting of
the arboreal habit has led to the emancipation
of the hand. For when the fore-limb was no
longer needed as a supporting member, it
became an instrument for touching and grasping,
for handling and lifting. And when monkeys
got a free hand they also got a nimbler brain.

CHAPTER VI
THE MASTERY OF THE AIR

What Getting into the Air meant— The Flight of Insects— Why
are there so many Insects? — The Flying Dragons — The
Flight of Birds — Different Kinds of Flying in Birds — Migra-
tion the Climax — The Fourth Solution of Flight — Fitnesses
of Birds and Bats — Attempts at Flight — Gossamer Spiders.

AGE after age life has been slowly creep-
ing upwards, becoming finer and finer
in its forms, and with greater freedom in its
ways. And who shall say that this progress
is going to stop? In any case the fact is that
for millions of years there has been among
animals a search after new kingdoms to
conquer, sometimes under the spur of necessity,
sometimes prompted by a spirit of adventure.
So after the open sea and the shore of the sea,
the fresh waters and the dry land, we come to the
air. The last haunt to be conquered was the air.
Of course there are no animals quite aerial.
These dancing May-flies, they spent two or
three years as aquatic larvae on the floor of the

232 THE HAUNTS OF LIFE

streams. These dragon-flies, whose mastery of
the air is almost perfect, had also a long aquatic
youth. Perhaps the swift comes nearest a
thoroughly aerial creature, for it is on the wing
from dawn to dusk, hawking insects without
stopping, except to deliver its captures at the
nest, never coming to earth at all — there is a
note of victory in its shrill cry !

WHAT GETTING INTO THE AIR MEANT

The surface of the earth is a hazardous
haunt, but getting into the air spells safety.
We see this clearly enough in the chagrin of
the cat when the sparrow rises into the air at
the last moment, after all the stealthy stalking.
It must be very disconcerting to be baulked so
neatly. Getting into the air means a return
to that universal freedom of movement which
animals had in the open water.

It means also getting off the ground often
arid and inhospitable, a power of rapid pursuit
of moving food, the possibility of quickly pass-
ing from scarcity to plenty, or from drought to
flowing water. It has led to an annihilation of
distance and to a circumventing of the seasons.
Last, not least, getting into the air means new

THE MASTERY OF THE AIR 233

opportunities of reaching suitable places for
laying eggs or bringing up the young. The
rooks' nests swaying on the tree-tops, what a
shrewd idea !

THE FLIGHT OF INSECTS

The problem of flight has been solved four
times by animals, and each time in a different
way. The first solution was that discovered
by insects. In insects the two pairs of wings
arise as hollow, flattened sacs, which grow out
from the upper part of the sides of the body.
They arise from the thorax region behind the
head, a region with three rings or segments,
each bearing a pair of legs. The wings grow
out from the second and third rings of the
thorax, and they have nothing to do with
limbs. While the wings of a bird are trans-
formed fore-limbs, the wings of insects are on
a different line altogether ; but we do not know
to what they can be compared — they are just
insects' wings !

The insect's body is very lightly built, and
the secret of the insect's flight is the extremely
rapid vibration of the wings, like the propeller
of an airship. A watch ticks sixty times in a

234 THE HAUNTS OF LIFE

minute, but many an insect, such as a humble-
bee, vibrates its wings 200 times in a second.
In most cases the hum or buzz is simply due
to the rapidity with which the wings strike the
air, and there is no structure, visible to the
naked eye, in the animal kingdom that moves
so rapidly as an insect's wing. When the
wings are large, as in dragon-flies and big
butterflies, the number of strokes in a second
is small. There is a fossil dragon-fly whose
wings taken together have a span of 2 feet
from one side to another, but there is nothing
like this to-day.

Insects vary greatly in their power of flight.
Many of the two-winged insects cannot fly
more than a few hundred yards, and can hardly
steer themselves at all, but are borne along by
the wind. This is true, for instance, of the
mosquitoes, the bite of which in some countries
often causes malarial fever. It is true also of
our common house-fly, which may cause disease
such as typhoid fever, by walking on our food
with dirty feet — for it revels in decaying matter,
and may come straight from a refuse-heap to
our jam-dishes and milk-jugs, carrying with it
disease-germs which find there highly favour-
able conditions for multiplying rapidly.

THE MASTERY OF THE AIR 235

It is useful for us to know that these insects
cannot fly far, for then we can protect ourselves
to a great extent by taking care that their
breeding-places — stagnant water in the case
of the mosquito, manure- and refuse-heaps
in the case of the house-fly — are not in the
immediate neighbourhood of our dwelling-
houses.

But many other insects have great powers
of flight. The beautiful, big, rainbow-coloured
or sapphire-blue dragon-flies, which are so con-
spicuous on our moors in sunny weather, fly
all day, and sometimes cover two or three miles.
They catch their prey of smaller insects on the
wing, and can suck the juices from them with-
out ceasing to fly. Their legs have become so
weak that they are of no use at all for walking,
but are used for perching, and for catching and
holding the prey. The bees, too, as we may
see for ourselves, are capable of strong and
rapid flight, and it has been proved that their
daily business of honey-getting may lead them
several miles from the hive.

The power of flight in insects sometimes
rises to a very high pitch. A wasp has been
known to fly tail-foremost for a quarter of an
hour in front of a bicycle. Dragon-flies, which

236 THE HAUNTS OF LIFE

gave some hints to the early makers of aero-
planes, are not only very swift, but have an
astonishing power of changing their direction
instantaneously. This is well suited for catch-
ing other insects on the wing. Another re-
markable feature in the flight of dragon-flies
is that when they pass from a sunny to a
shaded part they often begin at once to practise
that mysterious kind of flight called " soaring,"
so well seen in vultures circling in mid-air ;
that is to say, they continue moving, but with-
out any visible wing-strokes.

There is no end to the interesting peculiarities
of flight in different orders of insects. Bees
and their relatives have microscopic hooklets
on the front edge of the hind-wings which fix
on to a bar on the hind edge of the fore-wings,
so that the two wings on each side act as one.
In moths and butterflies the same result comes
about less perfectly. Beetles spread out their
heavy fore-wings — too heavy to be used in
striking the air — and clamp them at right
angles to the length of the body, so that they
serve as vol-planes when the lightly built hind-
wings strike the air. In two-winged flies the
hind-wings are turned into rapidly quivering
"poisers," each like a stalked half dumb-bell;

THE MASTERY OF THE AIR 237

they seem to be sense-organs, but their mean-
ing is obscure.

In their flight insects are often truly admir-
able, but it may be noticed that some fly only
once in their lifetime, namely, when they are
starting a new generation, and that some do
not fly at all. The simplest of all insects, the
Spring-Tails and Bristle-Tails, seem never to
have had wings, a state of affairs to be dis-
tinguished from what is seen in fleas, which
seem to have lost the wings their ancestors had
long ago. The flea, as every one is painfully
aware, makes up for its loss of flight by its
power of taking extraordinary leaps.

The leaping powers of many insects, such as
grasshoppers and crickets, suggest the theory
that insects originally used their wings as
parachutes in taking skimming leaps along the
ground or from branch to branch, before they
were able to use them to strike the air as
organs of true flight. Just as a creature must
walk before it can run, so perhaps the winged
insect had to jump and parachute for ages
before it could fly, until the muscles of the
wings grew strong. The fact that the wings
of insects often contain air-tubes and blood-
spaces suggests that they originally helped in

238 THE HAUNTS OF LIFE

respiration, which would raise the pitch of the
insect's life.

WHY ARE THERE SO MANY INSECTS?

Many naturalists estimate the number of
different kinds of living backboned animals
named and known at about 25,000. But of
named and known backboneless animals there
are ten times as many, and the most of these
are insects ! But some authorities on insects
insist that this computation is far too moderate.
They point out that, on the average, 6000 new
insects are discovered every year, and insist
that the total number of different kinds now
living on the earth must be put at over
2,000,000. As one of the experts says : "One
fact remains certain — namely, that the number
of species of insects is at least six times that
of all the other animals put together." And
besides the prodigious number of different
kinds of insects, there is the colossal number of
individuals that often represent a particular
species at one time. Why are there so many
insects ?

The first part of the answer is that most
insects have the power of true flight, which

THE MASTERY OF THE AIR 239

greatly increases their safety, their chances of
getting food, their possibilities of trekking and
migrating, and their opportunities — so plain in
the wasp's hanging nest — of laying their eggs
or nurturing their young ones in places of
comparative security, far from the ground,
where danger always lurks.

The second part of the answer is that insects
have an extraordinarily successful make-up.
Thus they have met the difficulty of capturing
oxygen by developing a system of branching
air-tubes (trachece), carrying oxygen to every
hole and corner of the body. The perfect
aeration is part of the secret of the insect's
intense activity and success. The blood never
becomes impure. Moreover, the beating of
the wings helps to drive the used air out,
letting fresh air in. Just as in birds, which
are also very successful, the flying helps the
breathing.

The third reason for the great success of
insects is to be found in their remarkable
development of instinctive behaviour. Along
a line which is quite different from intelligence,
they have been able to acquire a repertory of
ready-make tricks, an inborn ability to do
effective things right away without learning.

240 THE HAUNTS OF LIFE

It has its drawbacks, this instinctive capacity,
but it makes for success as long as the un-
expected does not happen.

The fourth reason for the surpassing success
of insects in the system of animate nature is to
be found in their variability or plasticity, linked
with that of the plant world. While the
fundamentals of an insect's body are always
the same, the details vary without end, and
this has enabled insects to find an unusual
number of niches of opportunity -, especially in
their vital linkages with the likewise very
variable, flowering plants. Now, the more
niches of opportunity a class of animals can
find, the greater will be its success.

A Russian naturalist, Chetverikov, has called
attention to a fifth reason for the success of
insects. It concerns their skeleton. In back-
boned animals the skeleton — of living gristle
or bone — is inside the body ; in insects and
other jointed-footed (Arthropod) animals the
skeleton — of not-living chitin — is outside the
body. Now it is argued that this entirely
different kind of body architecture made it
possible for insects to become very minute
without ceasing to be very effective. It was
more practicable to become small when the

THE MASTERY OF THE AIR 241

skeleton consisted of external, not-living,
durable but elastic chitin, than when it con-
sisted of internal, living, heavy bone. A
mouse is a mammoth compared with a midge.
Insects were able to fill minute niches of
opportunity ; their insignificance became their
strength. Most of the very large insects are
extinct ; the teeming insect world of to-day
consists in the main of small creatures, filling
the gaps, as it were, among the higher animals
which have evolved on quite different tacks.
So we understand better why there are so
many insects !

THE FLYING DRAGONS

The second solution of the problem of flight
was discovered by the extinct Flying Dragons
or Pterodactyls, which flourished in Cretaceous
and Jurassic times. They varied from a
sparrow's size up to a spread of 1 8 feet ; and
their wing was a sheet of skin spread out on
the enormously elongated, outermost finger,
which is usually reckoned as corresponding to
our little finger. They probably clambered
about the cliffs, and how far they could fly

we do not know. It is not likely that they
16

242 THE HAUNTS OF LIFE

were adepts, since the breastbone has only a
slight keel for the fixing on of the wing-
muscles ; and we know that in birds a
prominent keel is associated with highly
developed flying power, whereas the running
birds like the ostrich have no keel at all. On
the other hand, the Flying Dragons show, as
flying birds do, a solidifying of the middle
part of the backbone, giving the wings a firm
fulcrum against which to work. It is probably
quite safe to say that the Pterodactyls represent
a " lost race " ; they certainly were not the
ancestors of birds. It may be, however, that
the ancestors of the Pterodactyls and the
ancestors of our birds were related to one
another.

THE FLIGHT OF BIRDS

The third solution was a triumphant one : it
gave birds their mastery of the air. There
seems no doubt that birds sprang from an
extinct stock of Dinosaur reptiles which had
become bipeds ; and it is highly probable that
they were to begin with swift runners that
flapped their scaly fore-limbs and took long,
skimming leaps along the ground. When

THE MASTERY OF THE AIR 243

scales were replaced by feathers, no one knows
how, the primitive birds probably became
arboreal, and served a long apprenticeship as
parachutists, launching themselves from tree
to tree, until at last they learned to soar aloft.

It is all uncertain, but it is not unreasonable
to suppose that before birds became true fliers,
they were swift runners of spare build, with
light bones, a strong heart, very rich blood,
a hot skin, a power of keeping up an almost
constant body-temperature, a very good
digestion, a fine brain, and the further great
advantage that the flapping of the wings, even
before true flight was fully attained, helped the
breathing. A bird's body is a bundle of
fitnesses, well suited for flight, but it is in-
teresting to inquire whether the excellent
qualities of birds may not have been acquired
before they became fliers. But it is difficult to
do more than inquire ; we cannot roll back the
ages and see. We are not even sure whether
the Running Birds of to-day (the African
Ostrich, the South American Rhea, the Austra-
lasian Emu and Cassowary, and the Kiwi of
New Zealand) are the descendants of rather
primitive birds which never attained to flight,
or of flying birds which have lost their flying

244 THE HAUNTS OF LIFE

powers. Just as whales are the descendants
of land mammals which went back to the sea
(" secondarily aquatic"), so the Running Birds,
with no keel on their breastbone and no vane
in their feathers, may be the descendants of
flying birds which went back to the ground
(" secondarily terrestrial ").

There is a deep difference between the wing
of a bird and the wing of a Flying Dragon
or the wing of a bat — a deep difference in
spite of the fact that all three are transformed
fore-limbs. In the Flying Dragon and the
bat the wing is what is called a patagial wing
or web-wing, for what strikes the air is a
drawn-out sheet of skin. But although the
bird shows a little patagium or web stretched
in front of its wing, the whole secret of the
bird's wing is in the feathers, borne by the arm
and hand. In a ship the air strikes the sails,
in a bird the sails strike the air, and in the
bird the sails are the feathers. What made
the bird's flight possible was the growth of
feathers — feathers with the barbs united
together to form a stiff, but elastic, coherent
vane which does not let the air through when
they press against the air. How feathers
began — perhaps it took a million years to

THE MASTERY OF THE AIR 245

perfect them — no one knows ; but they have
the same general nature as scales, and perhaps
they may be thought of as glorified scales or
parts of scales.

DIFFERENT KINDS OF FLYING IN BIRDS

In the ordinary flight of a bird the wings
begin vertically above the back, and every one
is familiar with the "clap" that they make in
pigeons when they strike one another. They
are drawn forwards, downwards, and backwards
by the muscles which depress the wing, the
largest of which, for it has most work to do,
sometimes weighs half the whole weight of the
bird. At the end of the downstroke the wing
is pulled up again to begin another stroke. To
describe a complete movement four adverbs
are required — forwards, downwards, back-
wards, upwards ; and the tip of the wing moves
through a complex curve, like a figure 8 of
which the upper part is much the larger.

A bird is lightly built, but every bird is
heavy, and if it be killed it falls to the ground
with a thud. As Ruskin said, we go quite
wrong if we think of a bird as like a buoyant
balloon ; it is like a flying bullet. In other

246 THE HAUNTS OF LIFE

words, the bird has to exert itself to keep up
in the air. In the stroke of the wing it has
to displace — to thrust away from itself down-
wards and backwards — a mass of air bigger
than its own body. The resistance the air
offers to being thrust away is what keeps the
bird up.

If we watch birds we see that the first
strokes of the wings in lifting the body cost
them much. A Great Northern Diver cannot
rise off the ground at all, though by getting
some weigh on by swimming rapidly it can
launch itself clean out of the water. We often
see a cormorant taking a little run along the
rock to get up speed enough to enable it to
rise. Even after it has got launched in the
air it often strikes the water again and again.
Birds like to start from a vantage-point, and
a pigeon gets woefully tired if it has to start
many times in quick succession from the ground.
But note the important point : Ce n'est que le
premier pas qui coute ; once the bird has got
up a certain velocity in the air, the effort
required to keep itself up becomes beautifully
less. Sir Isaac Newton showed that it
decreases in proportion to the square of the
velocity, and this is a very important fact. If

THE MASTERY OF THE AIR 247

there is no wind against the bird and if the
bird is not rising, the work of rowing with its
wings in the elastic air is not hard. A ship
has the advantage that it floats in the water,
whereas the bird cannot float in the air ; but
the ship has the disadvantage that the water
offers considerable resistance to a body passing
through it, whereas the air offers little resistance
to a smooth body passing quickly through it.

The second kind of flight is gliding, seen
when a bird, having got up a certain speed,
rests on its oars, and holding its wings taut
glides along, or when a bird launches itself
from a tree and with outstretched, but un-
moving wings, glides to the ground. When
a bird glides along after getting up speed it is
bound to sink, but this may be counteracted
for a time if an ascending current of air beats
up against the bird's outstretched wings from
below. We often see this when a gull flying
from the fields seawards meets just above the
edge of the cliffs an ascending landward breeze.
In this case there is a transition to the third
kind of flight, called "sailing."

SAILING FLIGHT. — When an albatross goes
up one side of the ship, keeping pace with
the vessel, without a stroke of its wings, we

248 THE HAUNTS OF LIFE

see a marvellous thing, but the marvel in-
creases when in front of us the bird tilts its
body and turns, and comes towards us down the
other side of the ship, and all, so far as we can
see, without a stroke of its wings. This sailing
is, we think, the most wonderful locomotion in
the world, and the puzzle of it does not seem to
have been altogether solved. It is finely
illustrated by vultures " soaring" in mid-air,
describing circle after circle, ascending in a
magnificent spiral and sailing down again, and
all, so far as the field-glass shows, without any
stroke of the wings. The word " soaring " is
often applied to this mysterious kind of flight,
but, "sailing" is a better word. It is better to
keep "soaring " for the ascending flight of the
lark, where there is very rapid up-and-down
movement of the wings, without any backward
stroke. This leads on to the "hovering" of
the kestrel, where the up-and-down movements
of the wings are extraordinarily rapid, and to
the "fluttering" of a humming-bird, poised
like a moth before a flower. But sailing is a
different matter.

Sailing is seen in birds with a large wing-area
or sail-area in proportion to the size and weight
of the rest of the body, e.g. albatross, vulture,

THE MASTERY OF THE AIR 249

gull, raven. It is seen only when there is some
breeze, but there may be considerable wind
overhead when there is little or none near the
ground. For long intervals there are no
ordinary strokes of the wings, though it is a
bold thing to assert that the wings are not
moving at all. It is often associated with a
tilting of the body, which can be effected by
movements of head and neck, shoulder-joint,
and tail. It is not due to massive up-currents
of air playing upon the under surface of the
bird, for it is sometimes exhibited when light
objects like feathers are seen sinking slowly in
the air. It is highly probable, however, that
the sailing bird takes advantage of horizontal
currents of unequal velocity in the air. It is
also highly probable that the bird having got up
some speed by strong strokes sustains this velo-
city against the wind and rises in its sailing ;
that it turns and comes down with the wind,
getting up, without strokes, sufficient speed to
rise again. In other words, it is continually
changing " energy of position " into " energy of
motion," and conversely.

It is important, we think, to remember one's
own experience in such an exercise as skating,
that, given a certain speed, slight movements

250 THE HAUNTS OF LIFE

of the body, to one side or the other, bending
and straightening, may be very effective
although there is no actual movement of the
legs. Experienced mountain-climbers are also
aware of the importance of slight adjustments
which are eventually made almost without
thinking. In any case we are probably safe in
saying that the sailing albatross is not behav-
ing like a kite.

MIGRATION THE CLIMAX

The crowning advantage of the power of
flight in birds was that it enabled them to
migrate, to evade the difficulties of the winter.
In north temperate countries the great majority
of the birds show this seasonal mass-movement
between a nesting-place and a resting-place,
the former being always in the colder part of
the range. It is remarkable in many ways, this
migration of birds (see our Wonder of Life
(1914) and Biology of the Seasons ( 1 9 1 1 )) ; it
occurs in such a punctual, orderly way ; it is
such an intense activity, for many migrants seem
to keep up for hours on end a speed of a mile
a minute ; it means such an annihilation of
distance, for the Pacific Golden Plovers of

THE MASTERY OF THE AIR 251

Hawaii seem to think nothing of setting out for
Alaska ; it means some sense of direction that
we do not understand, for a young bird that has
never been more than a few miles from home
will start gaily in the autumn for tropical Africa
and will reach its goal in safety, and, what is
more, will sometimes come back again the
following spring to the precise place of its
birth.

THE FOURTH SOLUTION OF FLIGHT

The fourth solution of the problem of flight
was discovered by bats. In its idea it is nearest
that of the Flying Dragons, but it is quite in-
dependent and by itself. Bats are, of course,
true mammals, covered with hair, and giving
milk to their offspring. They are most nearly
related to the Insectivores, such as shrew and
mole, and it is interesting to notice that there is
in the Far East an aberrant insectivore called
Galeopithecus, placed by some authorities in
a special order, which has a sheet of skin
stretched between fore- and hind-limbs, and
is a very expert parachutist.

The wing of the bat is formed of a fold of
skin, which usually begins at the shoulder and

252

THE HAUNTS OF LIFE

FIG. 29.— WINGS OF DRAGON (A), BAT (B), BIRD (C).

THE MASTERY OF THE AIR 253

stretches along the upper margin of the arm to
the hand. The thumb, which is small and
clawed, is left free, but the membrane stretches
across all five palm-bones and to the very tips
of the four very long outspread fingers, and
from them to the legs. The knees are turned
outwards and backwards like our elbows, to
meet the membrane, which reaches down to the
ankles, leaving the feet free, but filling the
space between the hind-legs, and including all
the tail except its tip. The span of the out-
stretched wings varies from 2 inches to 5 feet.

This wing membrane is a very wonderful
thing. On a dead bat it looks like a piece of
dry, tough skin, but it is in reality so well
supplied with nerves and blood-vessels that it
is exquisitely sensitive. The bat is, in the
most literal sense, alive to its finger-tips, for
the sense of touch in the whole of its wing is
extraordinarily delicate. When it gets into a
room, as it often does, for light seems to attract
it, it will fly round and round without ever
knocking against wall, cornice, or wardrobe, and
out of doors will pass in and out among the
branches of a tree without coming in contact
with them, because of its power of feeling things
before it touches them. Its mouse-like ears,

254 THE HAUNTS OF LIFE

and the curious leaves of skin about its nostrils
are also very sensitive, but it scarcely seems to
need these to show it what to avoid when
flying. Some say that as the bat flies it utters
its high-pitched cry, and that the echoes of
this from branches and the like help it to
avoid obstacles.

On the ground the bat is very clumsy and
can only shuffle along, as indeed we should
expect from the fact that both fore- and hind-
limbs are taken up in the making of the wing.

All the bats in Britain — and there are about
fifteen different kinds — belong to the smaller
insect-eating section. They remain in retreat
by day, but on mild evenings they may often
be seen flying about in pursuit of the gnats,
flies, and moths on which they feed. The
commonest of our bats, which is also the
smallest, is known as the pipistrelle. Its body,
covered with reddish-brown fur, is only about
if inch in length, but the expanse of wing
makes it look much bigger in the air.

As cold weather approaches and insect life
gets scarce, the bats retire to winter quarters.
A cave, a disused chimney, the roof of a barn,
a church tower, a hollow tree — any dark, quiet
spot will serve their purpose. Like other

PLATE XIV. — BATS FLYING IN THE TWILIGHT.

THE MASTERY OF THE AIR 255

hibernating animals, they have stored up as
much nourishment as possible within their bodies
before laying themselves up for the winter,
and now they hang by their toes with their
heads downwards and their wings wrapped
about them, sleeping comfortably, though not
very profoundly, for a mild spell will wake
them up, until spring comes round again.
Quaint creatures that hang themselves up by
their toes and wrap themselves up in their
arms !

The young ones, usually only one at a time,
are born in May, and by July they are able
to fly with an uncertain fluttering movement
that makes them look like big moths in the
twilight.

The nature and abundance of their food
makes it unnecessary for our British bats to fly
very far, but some of the larger fruit-eating
bats of warmer countries make enormous daily
journeys in search of their favourite fruits. We
are told that the "flying fox," so called from
the foxlike look of its long, red-furred snout,
will fly many miles, and even cross an arm of
the sea, when there are orchards to be robbed.
The young one attaches itself firmly to its
mother's breast, and so can be carried without

256 THE HAUNTS OF LIFE

impeding her flight. Thus the bats, though
belonging to a class nearly all of the members
of which live on land, have become thoroughly
adapted to aerial life.

In insect-catching bats the skin is continued
from the hind-legs to the well-developed tail,
and this " inter-femoral membrane " forms a
very useful pouch. For when the bat has
caught a good-sized insect, such as a night-flying
beetle, the difficulty arises of crunching it with-
out letting it go from the grip of the jaws. In
her delightful Wild Animals of Garden and
Hedgerow (1920), Miss Frances Pitt points out
that the bat lowers its head to its skin-basket
and, pressing its booty against that, can crunch
it comfortably without risk of losing what it has
gained. During this process, which is quickly
over, the bat tumbles a little in the air, but
speedily recovers itself.

FITNESSES OF BIRDS AND BATS

Birds and bats are not in any way related to
one another, except that the two classes, birds
and mammals, may be traced back to a common
ancestry in extinct reptiles. It is all the more
interesting to find that similar fitnesses or

THE MASTERY OF THE AIR 257

adaptations for flight have been wrought out in
the bodies of bird and bat. Both are lightly
built as regards their skeleton, which means a
big surface for fastening muscles on to, without
great increase in weight. Both show a keel on
the breastbone for the better fixing on of the
muscles of flight, but the bat's keel is much less
prominent than a bird's. Both show a solidi-
fying of the middle region of the backbone,
which affords a firm fulcrum for the wings to
work against. In almost every other respect
they are as different as different could be, but
it may be noted that most birds and most bats
are small, as if there were a size-limit to flying
creatures. A bird like an albatross, with a span
of 1 1 feet from tip to tip of the outstretched
wings, is quite out of the common, and so are
the very large fox-bats of the Far East.

ATTEMPTS AT FLIGHT

Apart from man, the problem of flight has
been successfully solved four times — by insects,
Pterodactyls, birds, and bats ; but how often
has its solution been attempted? It is very
interesting to study these attempts, some of
them splendid failures.

258 THE HAUNTS OF LIFE

(A) There has been much discussion over the
FLYING FISHES, whether they show anything
that can be called true flight, that is to say,
whether their fore-fins strike the air or not.
The general answer, for the common flying fish,
Exocoetus volitans, which one sees when one
crosses the Atlantic, is that the creature takes
a great leap out of the water, using its tail as
propeller, and helped perhaps by the momentum
of a wave ; that it holds its pectoral fins taut,
without more than slight vibrations, and uses
them as vol-planes, not as wings ; that it may
for mechanical reasons rise in its vol-planing,
so that it lands on the deck of a ship ; and that
the alteration of the curve of movement is in
the main involuntary, being due to a slight
tilting of the body. We have watched the
common flying fishes with care and we never
saw anything approaching a stroke with the
fore-fins. We have seen them cross in front of
the prow of the steamer and, in the course of
their curve, come crashing against a port-hole.
The leaping is often a desperate attempt to
escape from their enemy the tunny.

In regard to the Flying Gurnard (Dactyl-
opterus) some good observers have described a
fluttering of the pectoral fins, which looks like

"si

to

4

26o THE HAUNTS OF LIFE

the beginning of flight, and there is no reason
why this should be called impossible. It has
to be remembered, however, that though the
muscles of the pectoral fins of flying fishes are
larger in proportion than in related fishes, they
are not much larger. It follows that there
cannot be much striking of the air. At the
most, there is only a beginning of flying.

Recent studies of flying fishes have shown
that the "flight" differs greatly according to
the atmospheric conditions. It is short when
the air is still ; it is long when there is a breeze.
In fact the " flight" of flying fishes sometimes
approaches the " sailing" of the vulture and
the albatross.

(B) Another attempt has been made by
some tree-toads, which take flying jumps
from branch to branch. In our common frog
there is a familiar web on the large hind-feet,
which is obviously well suited for striking the
water in swimming. In the flying tree-toad,
Rhacophorus, there is a web between the fingers
as well as between the toes, and thus the animal
has four parachutes.

(C) There is something fascinating in the
little Flying Lizard, Draco volans, of the Malay
States, which has gone far towards flight on an

PLATE XV.— FLYING DRAGONS (Draco volans) OF THE FAR EAST.
The parachute of skin is spread out on five or six greatly elongated mobile
ribs. Note the upper and the under surface. Also how the parachute is-
closed in when the animal — a Lizard after all — rests on the branch.

THE MASTERY OF THE AIR 261

FIG. 31.— FLYING TREE-TOAD (RHACOPHORUS).

262

THE HAUNTS OF LIFE

idea of its own. Like all other parachutists,
except the Flying Fishes, it lives in trees, and
it is able to take daring leaps from one to
the other. It has five of its ribs much elon-

FIG. 32. — THE LITTLE FLYING DRAGON (DRACO VOLANS)

OF MALAY.

Note the Pendent Pouch (P) on its Throat, and the Extended
Ribs (R) supporting the Parachute.

gated and very movable, and they carry out
between them a sheet of skin. When the little
dragon (Draco, its name) is resting we do not
notice much that is peculiar, for the long ribs
fold in and lie parallel with the backbone, like a

THE MASTERY OF THE AIR 263

collapsed umbrella. When it is going to " fly "
the ribs are extended and form the supports
of a fine parachute. The dragon can swoop
several yards, sometimes to avoid an enemy,
sometimes after a swarm of insects. The
upper surface of the body is brightly coloured,
and there is a curious dewlap on the throat.

There is another tree-lizard, Ptychozoon,
whose long tail bears a scolloped fringe of skin
on each side, and this again helps in swooping.
There is a tree-snake (Dendrophis) which dis-
dains all accessories and launches itself stiffly
from a lofty branch to the ground. But is
there anything in the way of movement a snake
cannot do except cross a sheet of ice or Ahorse-
hair rope ?

(D) What bats achieved many mammals
have attempted, that is, if we regard parachut-
ing as on the way towards flight. It is note-
worthy that all the attempts at flight among
mammals have been made in families that are
arboreal in habit, so that climbing tall trees may
have been the first step towards acquiring
wings or some substitute for them. Thus we
have the flying phalangers of New Guinea and
Australia, including many species, "the largest
of which is as big as a cat, while the smallest is

264 THE HAUNTS OF LIFE

no bigger than a mouse." All of them live
among tall trees and keep hidden in the
branches till evening, when they become very
active in search of the fruits, leaves, and insects
on which they feed. Their flight, too, is of the
parachute order, but it is much more effective
than that of the flying lizard. They have a fold
of skin covered with hair extending from the
fore-legs to the hind-legs, and, when they
launch themselves into the air from the top of
a tree, the outspread skin bears them up for a
considerable distance, and even enables them to
change their direction a little while in the air.
They cannot, however, move the fold of skin
up and down, and therefore they can only " fly "
to a lower level than they started from.

The "flying squirrels," mostly found in Asia,
have a somewhat similar arrangement, and
they are able to leap a distance of 20 yards.
The curious " flying lemur " or Colugo of
the Indian Archipelago has an even more
effective parachute, for its fold of skin does not
stop at the hind-legs but fills the space between
them, the long tail passing down the middle.
Mr. Wallace, the naturalist, observed the flying
lemurs in their native haunts, and he thus
describes their flight : " Once in a bright twilight

THE MASTERY OF THE AIR 265

I saw one of these animals run up a trunk in
a rather open place, and then glide obliquely
through the air to another tree on which it
alighted near its base, and immediately began
to ascend. I paced the distance from one tree
to the other, and found it to be not less than
seventy yards, and the amount of descent I
estimated at not more than thirty or forty feet,
or one in five. This, I think, proves that the
Colugo must have some power of guiding itself
through the air, for otherwise in so long a
distance it would have little chance of alighting
exactly on the trunk."

An interesting point in regard to these
parachuting mammals is that there are so
many which seem to be independent of one
another. It is worth while making a technical
list, because it shows how the same impulse
must have become urgent over and over again.

f Perhaps to be ranked
GALEOPITHECUS . . . A

I among the Insectivores.

Among the rodents, re-
ANOMALURUS ....

lated to squirrels, but
PETAURISTA

differing markedly from
SCIUROPTERUS ....

I one another.

PETAURUS TA11 of them Marsupials,

PETAUROIDES . . . J but not nearly related
AEROBATES I to one another.

266 THE HAUNTS OF LIFE

THE BALLOONING SPIDERS

In these parachutists, some of which have
their faces set towards flying, we get a glimpse
of what is certainly a quality of living creatures
— the quality of endeavour and experiment, of
insurgence and adventure. We cannot get the
right word for it, because it is a characteristic
of life itself, asserting itself at many levels.
We find it among the simple primeval creatures
of the Open Sea, which do not form " bodies"
in the strict sense, but expend all their
endeavour in fashioning their single "cell," so
that it is often like a fairy palace, and is a little
world of internal microscopic complexity. We
find it in the simple sedentary creatures of the
shallow water, whether seaweeds or sponges,
zoophytes or corals, which add to the self-pre-
servation law of the firstlings, as Dr. Church
says, the second great law that no race will
continue unless the individual members do
their bit in securing its continuance. We find
it in the instinctive behaviour of ants and bees,
in the instinctive and intelligent behaviour of
birds and mammals, in the instinctive, intel-
ligent, and rational behaviour of man.

No book nor naturalist can ever come

V

> V

» g
II

o «

§*

PL)

THE MASTERY OF THE AIR 267

within sight of the end of the study of the
haunts of life, but as we must close these studies
now, we wish to finish with a picture which may
serve as an emblem of the quality of life which
seems to us so characteristic. Our picture is
that of the Gossamer Spider, a terrestrial
creature which makes aerial journeys without
wings.

At many seasons of the year, but in the
autumn especially, many small spiders of
various kinds mount on to gateposts and the
rails of wooden bridges and tall plants like
ragwort. They stand with their head to the
wind, and allow threads of silk — four is a
common number — to float out from the spin-
nerets at the hind end of the body. When
these are long enough the wind grips them,
and the spider lets go, usually turning upside
down. On the wings of the wind, supported
by the silken parachutes, the spiders are borne
from one parish to another, from a crowded
place it may be to a free place, from a hungry
land it may be to a land of plenty. Some-
times they are borne in safety over a sheet of
water, though the tips of their toes may touch
the surface film. If the wind should rise, the
ballooning spider can wind in its threads, as

268

THE HAUNTS OF LIFE

we see one doing when it reascends the thread
by which it has lowered itself half-way from

FIG. 33. — GOSSAMER SPIDERS.
On their Aerial Journey.

THE MASTERY OF THE AIR 269

the roof. If the wind should fall, the spider
can pay out more thread. It is quaintly like
the sailor furling and unfurling his sails. When
the spiders feel they have had enough of aerial
journeying, they wind in some thread and sink
to the ground. When ten thousand little
spiders do this about the same time there is
what is called a shower of gossamer. The
countless threads are seen on the hedgerow
and on the ploughed field and on the lea, and
if we kneel down and look against the light we
see the quivering, glistening maze — an image
of the web of life itself. But what impresses
us most is the simple fact that a wingless
terrestrial creature journeys through the air.
It has attempted the apparently impossible and
achieved it. We are filled with a reasonable
wonder at the adventurousness of life.

INDEX

Acorn-shells, 40.
Aerial animals, 231.
Aesop Prawn, 51.
Albatross, 247.
Amphibians, 198.
Angler, 43, 93.
Animal locomotron, 206.
Arboreal animals, 229.
Argonaut, 100.
Autotomy, 50.

Bacteria, 147.
Barnacle, 96.
Bat skeleton, 257.
Bees, 235, 236.
Beetles, 236.
Bird skeleton, 257.
Bitterling, 150.
Blood, 1 88.
Blood-worms, 203.
Bracken, 148.
Breathing of insects, 239.
Buckie, 29, 30.
Bullhead, 161.
Burrowers, 226.
Butterfish, 13.

Camouflage, 51.
Cats and Clover ', 196.
Cave animals, 228.
Centipede, 195.
"Challenger" Expedition, 69,

106.

Circulation of matter, 28, 145.
Clarias, 221.
Climbing Perch, 221.
Cock-paidle, 56.

Collared Lizard, 208.

Colour of deep-sea animals,

129.

Coral-reef, 6.
Crayfish, 158.
Crumb of Bread Sponge, 37.

Darkness of deep sea, 112.

Deep-sea fauna, 119.

Diatoms, 68.

Dog whelk, 31.

Dragon-fly, 232, 234, 235, 236.

Dry land, 185.

Duckmole, 211.

Ear-bones, 188.

Earthworms, 193.

Eel, 141, 163.

Elver, 163.

Ermine, 220.

Eyes of deep-sea animals, 130.

Feathers, 244.
Feather-stars, 121.
Fishing-frog, 43.
Flight of bats, 251.

„ „ birds, 242.

„ „ insects, 223.

„ kinds of, 245.
Floating barnacle, 96.
Flounder, 142.
Flying dragons, 241.

„ fishes, 258.

„ gurnard, 258.

„ lemur, 264.

„ lizard, 260.

„ phalanger, 263.

270

INDEX

271

Flying squirrel, 264.

„ tree-toad, 260.
Food-supply of deep sea, 116.
Fresh Waters, 136.
Fresh-water mussel, 149.

„ snail, 151.

„ spider, 181.

„ sponge, 155.
Frog, 177-
„ on seashore, 13.

Gaff top-sail, 57.
Gill clefts, 187.
Glass-Rope-Sponge, 123.
Gliding flight, 247.
Gnat, 152.

Gossamer shower, 267.
„ spider, 267.
Great deeps, 104, 108.
Great Northern Diver, 246.
Great Salt Lake, I.
Guillemot's egg, 54.
Gunnel, 13.

Haemoglobin, 202.
Harlequin-flies, 203.
Harvest mouse, 213.
Hedgehog, 217.
Hesperornis, 85.
Hibernation, 217, 255.
House-fly, 234.

lanthina, 101.
Infusorians, 147.
Instinct, 239.

Jelly-fishes, 77, 91, 92.
Jerboa, 206.

King-crab, 14.

Lamprey, 172.
Land crabs, 223.
Land plants, 190.
Limpet, 21.
Lion, 214.
Lobworm, 15.

Luminescence, 124.
Lump- sucker, 56.

Mackerel, 70.

Malaria, 151.

Marine Lizard, 12.

Masking, 48.

May-flies, 179.

Migration, 250.

Mosquito, 151, 234.

Mother Carey's Chickens, 82.

Mudfish, 154.

Mudskipper, 222.

Nests, 210.
Niagara, 2.
Niners, 173.
Noctiluca, 72.
Number of animals, 238.
„ „ insects, 238.

Oar-fish, 90.
Ooze, 112.
Open sea, 64.
Otter, 10.
Oyster-catcher, n.

Palolo, 59.
Paper nautilus, 100.
Parental care, 215.
Pearls, 151.
Pelagic animals, 72.
Pellucid Limpet, 35.
Peripatus, 194, 212.
Periwinkle, 21.
Pholas, 24.

Phosphorescence, 124.
Piddock, 23.
Plankton, 75.
Polar bear, n.
Pressure of deep sea, 109.
Ptarmigan, 219.
Pterodactyl, 241.
Purse Sponge, 20.

Robber-crab, 141, 223.
Rock-barnacles, 40.

272

INDEX

Running birds, 243.

Sailing flight, 247.
Salamander, 159.
Salmon, 169.
Sandhopper, 58.
Sargasso Sea, 71.
Sea-anemones, 38.
Sea-butterflies, 94.
Sea-desert, 75.
Sea-grass, 35.
Sea-leech, 57.
Sea-lilies, 121.
Seals, 10.
Sea-mat, 16.
Sea-serpents, 89.
Sea-skimmer, 86.
Sea-snakes, 55, 88.
Sea-spider, 14.
Sea-squirts, 13.
Seaweeds, 31.
Shore, 3.
Shore-crab, 101.
Shore-fauna, 10.
Skate-sucker, 57.
Skipjack, 230.
Slipper Limpet, 27.
Soaring, 236.
Soaring flight, 248.
Spider's flight, 268.
Spiny Ant-eater, 218.

Sponges, 17.
Star-fish, 46.
Stickleback, 162.
Stinging animals, 16.
Stoat, 220.
Storm Petrel, 82.
Swift, 232.

Temperature of deep sea, in,
Tree animals, 229.
Tree-lizard, 263.
Tree-snake, 263.
Turtles, 87.

Underground animals, 226.

Venus' Flower Basket, 123.
Vulture, 248.

Wasp, 235.
Water, 156.
Water-flea, 95, 147.
Water insects, 177.
Web of Life, 149.
Whale, 77, 100.
White animals, 220.
Wing of bats, 253.

„ „ birds, 244.

„ „ flying dragon, 241.

„ „ insects, 223.
Winter sleep, 217.

PRINTKD BY MORRISON AND QIBB LTD., EDINBURGH.

UNIVERSITY OF CALIFORNIA LIBRARY,
BERKELEY

THIS BOOK IS DUE ON THE LAST DATE
STAMPED BELOW

Books not returned on time are subject to a fine of
50c per volume after the third day overdue, increasing
to $1.00 per volume after the sixth day. Books not in
demand may be renewed if application is made before
expiration of loan period.

OGT

-S22 -

JAN 11 1932
JAN lt> 1935

20m-l,'22

UNIVERSITY OF CALIFORNIA LIBRARY