latter are the warmest blooded of all vertebrates, the former are
coldblooded. The one wear feathers, the other scales. Nevertheless,
there is an intimate connection between them; the reader has doubtless
already learned from other sources the facts about their relationship,
so we will not here do more than recall a few of these facts. One is,
that the birds of earlier times had teeth in their beaks, and possessed
jointed tails. Another, that the Reptiles of earlier times included
forms that were able to fly. A third notable fact is the presence of
claws on the wings of some birds, showing that the wing of the bird was
not always wholly specialised for use in flight.
We owe to Professor Huxley, the recognition of the close relationship of
Birds and Reptiles, and the name Sauropsida (Reptile-like animals),
under which both are included. They agree in being air-breathers and
never having gills, except the rudiments present in the early embryo:
this distinguishes them from Amphibia. They agree in having the skull
set on to the back-bone by a single articulating surface or condyle; and
thus differ alike from Amphibia and from Vertebrata. They agree in
having the red corpuscles of the blood nucleated; and in this differ
from the Mammalia, in which the red corpuscles are non-nucleated discs.
From a popular point of view, we may say that the striking distinction
between birds and reptiles lies in beauty and ugliness. Even in their
eggs, the reptiles display no love for adornment, no colouring or
pattern. Fig. 44 shows the eggs of some reptiles.
[Illustration: FIG. 44.--Eggs of Reptiles, half the natural size.
_A_, of African Cobra. _B_, of Common English Snake. _C_, of Common
English Lizard, _Lacerta agilis_. _D_, of Elephantine Tortoise. _E_,
of Crocodile.]
The five chief groups of existing reptiles are the Chelonia (Tortoises
and Turtles); the Rhyncocephala, represented only by _Hatteria_, a
lizard found in New Zealand; the Lacertilia or Lizards; the Ophidia, or
Snakes and Serpents; and the Crocodilia.
Perhaps the most interesting point regarding the reptiles that can be
mentioned in brief space, is the fact that they present traces of a
median third eye, which have been described by Baldwin Spencer, in the
New Zealand Hatteria, and in other reptiles. It is situated on the roof
of the brain. While the structure in Hatteria shows it to be an eye, its
position corresponds with that of the pineal gland of vertebrates
generally; so that we find, in fact, the trace of a third eye in all
vertebrates, including ourselves. It is, however, a trace only. In the
Lamprey fishes as well as in _Hatteria_, it reaches a further degree of
development. This pineal eye has been compared in structure to the eye
of Ascidians.
The Birds, excluding the extinct form with teeth and a jointed tail,
to which the group name of Archæornithes is given, fall into two
groups. These are the Ratitæ, or Birds with Raft-like, _i.e._ flat,
breast-bones, and the Carinatæ, or Birds with keeled breast-bones. The
former include the African Ostrich (_Struthio_), the American Ostrich
(_Rhea_), the Australian Emu, the Cassowary of New Guinea, and the Kiwi,
or Apteryx of New Zealand; all of them birds that cannot fly. The
vast majority of birds belong to the Carinatæ, characterised by the
projecting keel (Carina) in the middle of the breast-bone. The presence
of this, which affords a safe attachment for strong muscles, is
associated with the power of flight. It is impossible to treat the birds
more fully in the space allotted to this little story, but a few words
about feathers, however, may find a place here.
The colour of feathers is a subject of much interest. Everyone is
familiar with the brilliant tints often presented by the feathers of
birds, and everyone who is a close observer of natural objects knows
that there are some feathers which are iridescent, changing colour
according to the direction in which light falls on them. It has been
shown by Dr. Gadow that this variation of the colour of a feather is due
to its structure; this may be described as prismatic, for the small
divisions of the feather present acute angular edges, which reflect the
light like the edges of a prism. These are symmetrically repeated all
along the feathers, so as to reflect the same colour throughout. Thus in
the plumage of the common red and green parrot, we see feathers that are
red when held in one position, and yellow when shifted to another
position; while there are also feathers that are blue when seen in one
position, and green when seen in another; the alternative colour being
the one next in order in the rainbow.
Another point regarding the colours of feathers has no doubt puzzled
many of our readers; and that is, the metallic quality of the colouring
in some exceptional feathers, and in these only. The feathers of the
parrot just referred to, are, for instance, simply red and yellow, or
blue and green; but the feathers of the peacock, though displaying the
same colours, show a metallic lustre which is wanting in the other case.
The feathers of the starling, the blackbird, and the black hen of the
farmyard, though not so brilliant as those of the peacock, are the same
as regards the quality of the light they reflect. The secret of the
difference lies in the greater opacity of the feathers named; they are
_black_ feathers, while those of the parrot are light-coloured. Now
after the metals themselves, there are few objects in nature so opaque
as the black pigment of a black feather. If a thin section through
the roots of young black feathers is cut for examination under the
microscope, the pigmented parts, although cut so very thin, appear
completely opaque. And just as a glass gives a better reflection when
backed by something opaque, so does the reflecting surface of the
feather. Hence it is that the quality of the colours reflected by these
feathers is what we call "metallic." If we ask for a definition of this
metallic brightness, other than the accepted fact that it resembles the
light reflected from metals, the artist will reply that it consists in
two things--(1) the greater brilliancy of the light reflected, that is
to say the greater completeness of the reflection; and (2) the entire
absence of those gradations of light which are afforded by the
reflections from any object, however dark, that possesses a surface
translucent, even in the smallest degree. "Metallic" reflections, in
fact, may be defined as those in which the greatest amount of light is
reflected, and the reflected sunlight receives from the reflecting
surface the least possible degree of modification. While the actual tint
of the colour reflected by a black feather, then, is determined by the
form and position of its angular ridges, the quality of the reflection
is determined by the opacity of the substance itself. It is interesting
to note that the opacity necessary for reflecting a "metallic" lustre,
may be produced by means of pigment, in the vegetable as well as in the
animal organism; for instance, in the dark centres of _Coreopsis_ (the
Beetle Flower), and several other fashionable garden plants belonging to
the Compositæ or Daisy family. Within the animal kingdom, we may note
that the metallic lustre is almost entirely confined to land animals;
their dry skins have more chance to develop opaque parts, than the moist
tissues of creatures that live in the water. The most familiar exception
to this rule is the Sea-Mouse, an Annelid worm found on English coasts
(p. 73), which receives its odd name because it is a fat oval creature,
covered with bristles, thus greatly differing in appearance from most
worms. The larger bristles, which are of a dark purplish-black colour,
have a bronze or golden metallic lustre. Various other annelids exhibit
brilliant rainbow colours; for example, _Nereis_, the Rainbow Worm, also
found on English shores; but without the underlying black opaque
pigment, the reflections from the surface fall short of absolutely
metallic brightness. On land, we see among the insects innumerable forms
which present a metallic lustre, the beetles being the most notable in
this respect. To return to the vertebrates, from which we started,
everybody must have noticed that the fur of a clean well-kept black cat,
when lit up by the bright sunlight in which the animal loves to bask,
shows little rainbow reflections of red and green. These are due to the
presence of little grooves and irregularities on the surface of the
hairs, which play the same part in breaking up the light which they
reflect, as do the sharp angles of iridescent feathers. Like the
iridescence of the Rainbow Worm, they fall short of absolutely metallic
brightness; the fault in this case being due not to the nature of the
underlying stratum, so much as to the incomplete development of the
light-reflecting grooves. Yet this instance serves to show the part
taken by the dark pigment; for while the play of colours is perfectly
obvious in the fur of a black cat, it is almost impossible to
distinguish it in the case of cats with fur of lighter shades.
The Mammalia, or animals that suckle their young and produce them by
birth, were formerly considered to be sharply defined from animals that
lay eggs, such as the birds and reptiles. But in 1884 Mr. Caldwell
confirmed the statement which had been made previously, yet hardly
credited by the scientific world, to the effect that the lowest form of
mammals lays eggs. This, the Duck-Mole or _Ornithorhyncus anatinus_
(Bird-billed animal much like a goose), is a native of Australia and
Tasmania. It lives on the banks of rivers, and burrows in the bank. It
has webbed feet, and therefore sometimes receives the name of Platypus
(flat-foot). It lays eggs two at a time, in its burrow; and these eggs,
like those of other egg-laying vertebrates, have a yolk.
A kindred form, _Echidna hystrix_ or Spiny Ant-eater, is found in
Australia, Tasmania, and New Guinea. The _Echidna_ hatches its young
in a temporary pocket, which appears in the neighbourhood of the
breasts, and disappears after the young are old enough to take care of
themselves. The _Ornithorhyncus_ has fur, the _Echidna_ has spines, with
hairs between them. Neither bears the slightest resemblance to a bird;
the comparison suggested in the name of _Ornithorhyncus_ is fanciful,
and depends chiefly on the flat beak-like mouth; these egg-laying
quadrupeds may, however, be reasonably brought into comparison with
Reptiles. Neither of them has any teeth; the _Echidna_ has no teeth at
all; the _Ornithorhyncus_ loses them at an early stage of growth, and
develops instead hard horny patches in each jaw. With these it crushes
its food, which consists of small insects, worms, etc. The _Echidna_, on
the contrary, lives in rocky places, and feeds on ants, which it
searches for with its long-pointed snout. These two genera are grouped
under the name of Prototheria or Primitive Mammals.
The pocket in which _Echidna_ hatches its young, suggests a relationship
with the next group, the Metatheria or Marsupialia, which are the
characteristic mammals of Australasia. These are distinguished by the
possession of a permanent nursery-pocket, the "marsupium." In this they
put their young, which are born, like those of other mammals, not
hatched from eggs like those of the last group. They are, however, born
in a very backward condition, and therefore require to go through a
further period of incubation, so to speak, in the marsupium. Here each
one attaches itself to a teat, to which it remains fixed. But it cannot
suck as a new-born kitten or puppy does; and the milk is forced down its
throat by the muscles of the teat.
[Illustration: FIG. 45.--Skull and Lower Jaw of Great Kangaroo,
_Macropus giganteus_, much reduced.]
The Marsupialia are not entirely confined to Australasia; a few occur
in South America, and in North America they are represented by the
"'possum," _i.e._ Opossum, of American stories. The Marsupials seem
almost to mimic the forms of ordinary quadrupeds. Thus _Notoryctes_, a
form discovered a few years ago, mimics a mole. The fact is that, just
as among the Eutheria, or higher mammals, special types have become
established, possessed of certain habits, and especially of certain
habits with regard to food, and modified in accordance with those
habits. Thus there are among them savage carnivora, harmless herbivora,
and rodents; and these respectively share certain characteristics in
common with the carnivora, herbivora, and rodents, belonging to the
Eutheria. One of the herbivorous marsupials is the Great Kangaroo,
_Macropus_. It gets its name, Large-foot, from the size of its
hind-paws; on these it stands, and by their aid it takes remarkably long
leaps. Its skull is shown in Fig. 45; this, however, has not the full
set of teeth, some of which are soon shed. It crops the herbage with its
front teeth, and grinds it with its back teeth, like other herbivora.
[Illustration: FIG. 46.--Skull and lower jaw of Rodent; _i_, _i_,
incisor teeth, separated by a long interval from the molars. About
one-half the natural size.]
The study of the teeth is of great help in the classification of the
Mammalia. Of the eight orders of the Eutheria, two alone, the Sloth
order and the Whale order, show a tendency to the suppression of the
teeth. Those of the herbivora and carnivora may easily be compared by
anyone, in the sheep and the dog respectively. Fig. 46 shows the skull
of a Rodent, with elongated front teeth, adapted for that persistent
gnawing which makes the animals of the order, such as the Rat and
Rabbit, so terribly destructive.
TABLE SHOWING THE CLASSIFICATION OF THE MAMMALIA
{ 1. PROTOTHERIA, or EGG-LAYING MAMMALS.
{ One order, the MONOTREMATA.
=MAMMALIA.= {
{ 2. METATHERIA, or MARSUPIAL MAMMALS.
{
{ 3. EUTHERIA, or HIGHER MAMMALS.
The Mammalia are a terrestrial group. Exceptions are the Cetacea
(Whales), Sirenia (Dugongs), and Seals or Sea-Carnivora, but all of
these are air-breathers; even the Whale can only stay under water for a
limited period of time. Hence we see that none of them are really
animals belonging to the water; they are land animals adapted for life
in the water.
This brings us very near to the last chapter in the Story of Animal
Life. We have seen that our story began with the One-celled Animals, and
went on with the tale of the Two-layered Animals, in which each layer
was built up by cells in partnership. From Two-layered Animals we passed
to Three-layered Animals, and from them to Three-layered Animals with a
"body-cavity." When we reached the latter, we found amongst them traces
of the ancestry of the vertebrates. From the lowest of the Vertebrata,
the Lancelet, we passed on to the Lamprey, and from that to the true
fishes. In the latter we found the parent type of all the other
Vertebrata, possessing gills in the adult, while the latter only possess
them, or traces of them, in early stages of growth. The Amphibia formed
a group to themselves, in which we traced the loss of gills in the
adult. In the Reptiles, four-legged egg-laying animals, we found not
only a close relationship with birds, but also, through the four-legged
egg-laying _Ornithorhyncus_, a relationship with the Mammalia. The last
group comprises all the furry animals, and culminates in the order
Primates, in which the great Cuvier included Man.
TABLE SHOWING THE DISTRIBUTION OF ANIMAL LIFE BETWEEN LAND AND WATER
KEY TO TABLE:
A ARTHROPODA.
B VERTEBRATA.
C CHORDATA.
LAND WATER
Except a few forms living --All the PROTOZOA.
living in damp
places, or as
parasites
--All the SPONGES.
--All the COELENTERATA.
Except a few forms --VERMES.
terrestrial, and
many parasitic
Insects, except --A very few adult forms and }
Except Wood-lice and a few larvæ. }
a very few others --CRUSTACEA. } A
Spider-like animals, }
except --_Limulus._ }
--All the BRACHIOPODA.
--All the POLYZOA.
--All the ECHINODERMATA.
Except the Land-snails --MOLLUSCA.
--HEMICHORDATA. }
--UROCHORDATA, or Ascidians. }
--All the Fishes: (some few can }
exist in damp places) } }
Amphibia belong to both. } }
All the Reptiles --Except swimming forms, } }
which are nevertheless } }
air-breathers, only } }
partially adapted for } }
water life: Tortoises } }
and Turtles, Crocodiles } }
and Water-Snakes, _e.g._ } } C
} }
All the Birds: swimming and } B }
diving forms are only adapted } }
for temporary visits to the } }
water } }
All the Mammals --Except Whales, Sirenia, } }
and Seals, which are } }
nevertheless } }
air-breathers, only } }
partially adapted } }
for water life. } }
Another volume of this series, "The Story of the Earth," has already
dealt with the distribution of animal life in time; while "The Story of
Animal Life in the Sea" tells about the present inhabitants of the
ocean. It is therefore unnecessary to say much in this volume regarding
the distribution of animal life. A table is, however, appended, which is
not without interest. It shows how the chief great groups of animals are
divided between land life and water life, whether in fresh water or
salt. It will be seen that the terrestrial animals are much in a
minority, and that they belong, for the most part, to the higher types.
They are, in fact, stragglers, bold emigrants from the early home of
animal life, which lies in the more shallow parts of the waters of the
sea.
CHAPTER XV
MAN
If we are to accept the opinion of Dr. Isaac Watts, man, as a moral
being, is distinctly inferior to the "birds in their little nests," who
live in harmony with one another; and, again, if we are to believe
Solomon, he is by no means always the equal in intelligence of the Ant.
Yet somehow it came as a shock to many who had been accustomed to revere
both these authors, when they were asked, early in the latter half of
the nineteenth century, to regard man, from a zoological point of view,
as just a little superior to the Apes.
Then arose a great agitation as to the possibility of finding the
Missing Link. We shall see later on in this chapter, that if Research
had been content, like Charity, to begin at home, its industry would
have been duly rewarded.
But inquiry, carried far afield in time and place, has not been without
result. For it is generally believed that the remains found in 1894 in
Java by Dr. Eugène Dubois, are veritably those of the Missing Link.
These remains, which consist of the top of a skull, two teeth and a
thigh bone, belong either to the oldest Pleistocene age, or to the upper
Pliocene; they are found in association with the remains of other
animals, among which are included some forms now extinct, or absent from
that region. These ape-like remains have been carefully compared with
those of the lowest races of man which have hitherto been found in a
fossil state, and the result of the comparison is as follows: Of twelve
experts present at the Zoological Congress held at Leyden, "three held
that the fossil remains belonged to a low race of man, three declared
them to be those of a man-like ape of great size; the rest maintained
that they belonged to an intermediate form, which directly connected
primitive man with the anthropoid apes" (Haeckel). To the creature
represented by these bones has been assigned the name of
_Pithecanthropus erectus_, the Upright Ape-Man.
Let us now return from the subject of the Java fossil to those inquiries
which, as we have above suggested, begin at home. We have already
referred to the great principle of modern zoology, that the history of
the development of the individual sums up the history of the development
of the race. Of late years it has occurred to scientific men to apply
this principle in the case of human beings, and to ask, "What can the
baby teach us?"
The Baby, for one thing, has a very small nose, insignificant compared
with the size of its jaw. At least scientists find that this is the case
with their babies--if would, of course, be invidious to make such a
remark regarding their friends' children; and still more so to add, that
in this the Baby differs from the human adult, and somewhat resembles
the Ape, in which the nose is still less prominent, and the jaw still
more so. Observations have been made, too, regarding the Baby's
remarkable power of "holding on" with its hands. While a Baby is, in
most respects, a very weak creature, yet its powers of grip have been
favourably compared with those of adult human beings. No one who has
ever tried to rescue his watch or his hair from the clutches of a
friend's Baby, will feel inclined to doubt the conclusions of scientific
observers regarding the point in question.
The observations above referred to were made by Dr. Louis Robinson. He
drew his conclusions from the study of sixty cases, all of them infants
less than a month old; and of these at least half were tested within an
hour of their birth.
In every instance except two, says Dr. Robinson, the child was able to
hang on by its hands to the finger, or to a small stick three quarters
of an inch in diameter, and to sustain the whole weight of its body for
at least ten seconds. "In twelve cases, in infants under an hour old,
half a minute passed before the grasp relaxed, and in three or four
cases nearly a minute." In infants of about four days old, increased
strength was shown, and "nearly all, when tried at this age, could
sustain their weight for half a minute. At about a fortnight or three
weeks after birth the faculty appeared to have attained its maximum,
for several at this period succeeded in hanging for over a minute and a
half, two for over two minutes, and one infant of three weeks old for
_two minutes thirty-five seconds_!" "Thus," says Dr. Robinson, "a
three-weeks-old baby can perform a feat of muscular strength that would
tax the powers of many a healthy adult. If any of my readers doubt
this," he adds, "let them try hanging by their hands from a horizontal
bar for three minutes."
In these facts Dr. Robinson finds something to remind us of the
ape-babies that owe their safety to their capability of holding on to a
tree-climbing mother; and also something to suggest connection with an
ancestor which, although well accustomed to the use of its hands, had
yet to learn the use of its feet for walking on flat ground.
The same author, in discussing the "Meaning of a Baby's Footprint," has
shown that the foot of a young child bears traces of adaptation to a
state of existence in which it was used for purposes other than that of
walking.
"The toes of infants," says Dr. Robinson, "are much more mobile than
those of adults. The great toe is shorter than the second and third,
and is often separated from the second by a considerable interval.
The four outer toes can be, and frequently are, bent downwards so as
to show a distinct knuckle on the upper aspect of the foot at the
metatarso-phalangeal joint, and when at the same time the great toe is
flexed and turned inwards towards the sole, the front part of the foot
makes a very respectable fist. The great and little toes are often made
to approach one another beneath the rest, and I have seen one child who
could almost make them touch, and who habitually would endeavour to make
the great toe oppose the others when any graspable object was brought
into contact with the front part of the sole."[E]
[E] _Nineteenth Century_ for May, 1892.
Regarding the lines in the sole of the foot, Dr. Robinson says: "The
sole is covered with lines of a character exactly similar to those on
the hand; and when the toes are bent downwards these become deep
creases, showing that they are, like the palmar lines, the natural
folding-places of the integument to facilitate the action of
grasping.... The lines are scarcely visible at fourteen months old, and
are only present in a few cases after the age of two years. In adults no
trace of them can be seen when the foot is at rest, and only the
faintest indication at one or two spots when the toes are flexed to the
utmost. The obliteration is doubtless owing to the foot being used as an
organ for progression rather than prehension, and it will be seen that
the most distinct line crosses the sole at the spot where the epidermis
is always dense and callous, and the subcutaneous tissues thickened into
a cushion-like pad by the pressure and friction consequent on walking.
This line undoubtedly marks the place where the chief fold in the skin
was situated, when the toes were habitually clasped round some object
such as the branch of a tree." It has been pointed out by other writers
that the lines of the sole of the foot can plainly be seen in the adult
foot of some savage races. It must be added, however, that the survival
of the lines in the adult civilised foot is by no means so rare as Dr.
Robinson's remarks would lead one to suppose. I have seen instances in
which they were quite clearly marked. It must be added that anyone who
wishes to confirm my observations in this respect must be careful not to
mistake lines of disfigurement, caused by the pressure of boots, which
are sufficiently common, for the primitive lines of the foot.
The child, as it grows, ceases to remind us of the ape. Its nose gets
bigger as its toes cease to wriggle and learn to stand. But, for years
of its life, it is only too apt to remind us of the savage. How greedy
it often is! How readily it snatches that which does not belong to it!
How quick it is to quarrel with its playmates, and to fight! How noisy
when at play! How cross when it meets with disappointment! How fond of
tawdry things! In all these qualities we see the history of the race,
repeating itself in the life of the individual. The savage has preceded
the civilised family--the child shows us the faults of a lower race.
With the elapse of years they disappear, and are replaced by the more
amiable and gracious manners of the adult human being.
Nor do we need to go into the nursery to find links with our inferiors.
Much, indeed far too much, has been written of late years about
"atavistic degeneracy"; that is to say, degeneracy which imitates the
characteristics of our forefathers. Many things which are classed as
diseases, whether of the body, mind, or moral nature, may be explained
in this way. Take the gills, which, as we have stated, exist in all
vertebrates, but not in the adult of the highest groups. In a sickly
individual, even among the highest vertebrates, traces of these are
sometimes seen existing in the adult, as a gap or open space in the
neck, called by the medical man "cervical fistula": this is an instance
of degeneracy in the body. Take, for another instance, the kleptomaniac,
who snatches up everything he takes a fancy to, although he is not in
want. This is degeneracy of the mind, a relic of savage nature out of
place in civilised man. Yet the gill-space is an ancestral feature which
has its right time to appear, though it is out of place in the adult;
and the "want-to-snatch" stage, as we have already seen, is quite
natural in the young child. A parallel instance to the last is that of
the hysterical girl who invents all sorts of tales about her harrowing
adventures, weaving in stories she has heard of other people, with an
account of her own life. She is an impostor; but her instinct for
weaving yarns is that of the savage, who is the more admired by his
fellows the more he can show himself a liar. Even the dangerous
criminal, such as the Anarchist assassin, is comparable with the
treacherous savage, who stabs his guest, and with the fierce animal that
bites the hand that feeds it.
The causes of degeneracy may seem obscure. But if we turn to our
gardens, how easily is the process understood! Leave a cultivated plant
to look after itself; neither watered, nor manured, nor weeded; and how
long will it be before the plant resembles its wild ancestors? The
flower will be less fine, the leaves more weedy; the whole aspect of the
plant is changed. The causes: insufficient food and water, and the
struggle for root space, standing-room, and light, with the weeds
around it. Just in like manner the human being, when unfed, unwashed,
and untaught, begins to degenerate. The want of fresh air and light
associated with slum life, and even in the country, associated with the
homes of the poor, are factors in the case that are not to be forgotten.
Add to these drink, and the other sins of the fathers which are visited
on the children. All these are among the causes of degeneracy.
Nay more, the very virtues of the parents, as we account them, may lead
to the degeneracy of the offspring. Overwork, either physical or mental,
causes the deterioration of the family, and in our days nearly every man
successful in any career, either commercial or intellectual, is guilty
of overwork. The "haste to be rich," equally with the haste to be
famous, tells on the next generation. Those who are fond of moralising
at the expense of their neighbours, enjoy pointing out the
unsatisfactory careers of the sons of men who have become rich. Almost
invariably such a one is idle, we are told, and fond of pleasure.
Good cause has he to be so. He comes into the world with weakened
constitution, owing to his father's strenuous career; and if he were to
work as hard as his father, he would probably soon be dead; or at least
his children, in their turn, would be miserable and diseased. Nature
guides his inclinations, and whispers "Do not work too hard," "Do not
deny yourself too much"; and thus, so long as his father's money
maintains him, his life is preserved.
What is the kind of degeneracy that overtakes the family of the
brain-worker? The modern world is full of it. We owe to the unamiable
genius of Max Nordau a criticism of the intellectual world of the
present day, which attributes well-nigh all the follies of intellectual
cliques to degeneracy. Poetry, which is "full of sound and fury,
signifying nothing," rich in rhyme and alliteration, but wanting in
sense; art which seeks effect by loud and inharmonious colours; music
which rejects "mere melody": in these the critic sees the taste of the
savage, fond of a jingle of words, fond of bright colours, and ignorant
of middle tints; and fond of noise without a tune.
The so-called æsthetic movement which, a few years ago, wrought such
marvels in decoration and in dress, comes in for a share of the critic's
analysis. The dull senses of the degenerate cannot appreciate the soft
colours which ordinary persons like to look at; to attract his attention
and to please his fancy, he must have staring red, or staring blue. Or,
if he possesses an object which is of special interest, he must bring
this into contrast with a very sombre background, lest by chance it
should miss being seen.
I met with an amusing instance the other day which is much to the point.
In a remote part of the British Isles, two friends, immigrants from the
world of "culture," had been criticising the landscape. It was a pity,
they agreed, that everything was so grey and dull; otherwise the
neighbourhood might have been pretty. If only the cottagers could be got
to grow something in their gardens that would give a touch of _colour_
to the scene! These poor creatures had before their purblind sight all
Nature's rich harmony of colour, which affords such pleasure to persons
of true taste. Green fields, brown rocks, blue sea, and blue sky, all
were dull to them. Wild flowers of a score of kinds, and bright with
every colour--these were too insignificant to be visible. They wanted
some big patch of vivid colour, perfectly inappropriate to the climate
and surroundings. Some exotic plant was needed, in their opinion, to
give a touch of brightness. The harmony of colour and beauty of form in
our native plants, and in the common flowers of cottage gardens, were
imperceptible to their unobservant eyes. Their intelligence was on a
level with that of the savage, who is impressed by new and striking
objects, and delighted by gaudy colours, but finds no beauty in wild
nature or in accustomed things. These people were typical specimens of
the degenerate of the book-reading classes; dull of understanding and
wanting in taste, as the result of mental overwork in several successive
generations; immeasurably inferior in æsthetic capabilities to the
untaught peasants and fishermen of the district they would fain
enlighten--for these appreciate the beauty of their country, and love
its flowers.
Much might be added regarding atavistic degeneracy, as an explanation of
the mental and moral defects of human beings. Its most frequent form,
perhaps, is that of mere laziness. The Ape does not work; nor does the
savage, if he can possibly help it. Civilised man, if thoroughly sound
in mind and body, likes activity, and activity with a purpose. The poor
man takes a pride in his labour; the rich man takes a pride in his skill
in games, his learning, or his efforts to benefit others. The idler,
disinclined for either hearty work or hearty play, is a Degenerate. Of
late there has been much discussion of a plan for treating the confirmed
idler as a criminal. It will be seen from the remarks made above, that
there are equally good reasons for treating him as an invalid. In
criticising the plans of would-be reformers, this fact should not be
forgotten. He was a wise man who said "You cannot, by passing an Act of
Parliament, make a Vice into a Crime."
It must, however, be remarked that the doctrine of degeneracy has lost
both in force and in usefulness, by the treatment it has received at the
hands of those who have constituted themselves its popular exponents.
Some of these writers have made it but too evident that their criticisms
are often captious, and that their definition of degeneracy includes all
human failings--except their own. The reader who devotes a little
attention to the subject will, however, readily find an explanation
of this: for he will easily recognise, in the popular writers on
Degeneracy, the characteristics of the Degenerate, as described by
themselves.
First, the choice of a disagreeable subject, when the whole field of
science lay open to them: for the Degenerate prefers a disagreeable
subject. Secondly, the almost universal discovery of causes of
dissatisfaction, in every possible direction: for the Degenerate is
always vexed with everybody--except himself. Again, the want of
principle shown in appealing to the morbid tastes of the public,
by laying before it information on disagreeable subjects: for the
Degenerate is lacking in principle; what does it matter to him how much
harm is done to weak minds by his writings, so long as he sees in such
writings a safe means of securing eager readers and liberal pay? Again,
the Degenerate seeks notoriety; and this is easily secured by writing
books that discuss the morbid side of life.
Above all, the habit of carrying the war of criticism into regions of
art and culture with which the writer is obviously unfamiliar: this
also marks the tendency of the writer's mind. To criticise the doing of
that which he can by no means do; to destroy that which he can by no
means make; to leave no margin of leniency in his judgment, for the
imperfections which disfigure all human work: these are the familiar
failings of youth, of the unripe mind. They are also those of the
type of mind that never attains ripeness--of the Degenerate: we are
forbidden, on high authority, to apply to our brethren a shorter and
less modern term.
But although the doctrine of Degeneracy has thus found its way to the
general reader in a form which is often much to be regretted, it is
nevertheless a doctrine which, if wisely used, may lead to the most
beneficial results. Already it is widely recognised, by the thinkers of
all nations, that the theory of degeneracy, when thoroughly understood,
must revolutionise our treatment of the criminal classes. Instead of the
attempt to punish, civilised legislation must eventually, in many cases,
substitute a system of restraint.
It is useless to try to reform the idler or the thief, whose instinct
for idling or thieving is as imperative as a cat's instinct for catching
mice. So long as he goes free, so long will the instinct reassert itself
at every renewal of opportunity. Repeated punishment of the offender,
who is powerless against his own impulses, is frequently a mere cruelty;
while his repeated release, at the termination of every punitive
sentence, is, on the other hand, still more certainly, a cruelty to the
community at large, which he afflicts by his presence. Public opinion is
gradually becoming awake to the necessity for fresh methods of dealing
with these problems; it is by the patient investigations of scientific
men that it has been enlightened.
TABLE SHOWING THE PLACE OF MAN IN CLASSIFICATIONS
=Grade IV.= TRIPLOBLASTIC Animals with a BODY-CAVITY.
=Group.= CHORDATA; Animals with a Notochord.
=Phylum.= VERTEBRATA; Animals with a Back-bone.
=Class.= MAMMALIA; Animals that suckle the young.
=Order.= Primates.
=Genus.= Homo, i.e. man.
_Species._ Sapiens (possessed of sense).
Meanwhile, it must not be forgotten that the theory of degeneracy
has its cheerful aspect. It enables us to look at the offending
fellow-creature who belongs to the criminal classes, as an incomplete
development rather than as a hardened sinner. It reminds us, too, that
the criminal and the idler of to-day are now, what in the times of
savagery and animalism, every man once was. The degenerate criminal, in
fact, stands as a landmark, to point out the progress which has been
made by the human race. This was the starting-point, where now he
stands. How great the progress that is measured by the distance between
him, and the orderly, kindly-hearted citizen of the present age!
CHAPTER XVI
HOW ZOOLOGISTS DO THEIR WORK
It is one of the most well-worn of commonplace sayings, that "one half
the world does not know how the other half lives." It is equally true
that one half the world does not know how the other half works; and
especially is this the case when one of the world's halves is its
learned, and the other its unlearned, half. The average business man
probably has an idea that the man of learning has a pretty easy time of
it, and that his most arduous occupation is to enlighten an attentive
world by reading papers at the meetings of the British Association
and the Royal Society. He has a vague idea that the man of learning
sometimes uses midnight oil, but it would surprise him to be informed
that the man of learning often sets to work at five o'clock in the
morning--as is actually the case. And well he may, considering the
magnitude of the task he has in hand, and the variety of the odds and
ends of labour that it includes.
_Firstly_, how does he obtain the raw material for his work? The
scientist, like the cook, must "first catch his hare" before any further
details of work can be arranged. He does not, as a rule, do this in
person, except when an animal of unusual interest is concerned. An army
of collectors, all the world over, are constantly busy in searching for
material for the zoologists, on land and sea. They look for employment
and pay to the museums and laboratories of the learned world. When the
specimens arrive, what is to be done with them? Some arrive alive, and
may be dismissed from present consideration. The dead specimens give
employment to a number of workers who are under the command of the man
of learning. There are skins to be mounted and stuffed, bones to be
articulated and set up, each practically the work of a different trade.
There are drawings to be made of all important specimens, a task which
affords employment for the artist and the photographer. There are
carcases large and small, to be immersed in preservative fluids until
they can be thoroughly examined in detail. And woe betide the zoologist
who allows any of these tasks to be performed without his own personal
supervision. He will realise, as all careless masters do, that blunders
may be made in an hour, which cannot be repaired in a day. But when all
is done that servants and helpers can accomplish, the real business
remains to be done. Is there among the specimens one which has not been
thoroughly overhauled by other writers, one whose every detail of
structure is not already to be found printed in a book? That one must
be examined with the utmost accuracy. If it is big enough, it must
be dissected, and every part recorded and figured in diagrams. But
suppose it is a small creature, whose parts can only be seen under the
microscope, a long series of processes are necessary before it is ready
for use. In its fresh state, it contains a quantity of water, and if
left to itself would shortly decompose. Even if already immersed during
carriage in various preservative fluids, it still contains much water,
and, if so, neither will it keep for an indefinite length of time, nor
could it be satisfactorily examined under the microscope. It must be
soaked in one of various chemical solutions, to harden and preserve
it. If very small indeed, a mere speck, it perhaps only needs to be
transferred to a fluid in which it can be "mounted" and placed under the
microscope. But with the vast majority of specimens, an immense amount
of labour is needed before they are ready for inspection under the
microscope.
This will easily be understood if we reflect for a moment on the way in
which objects are examined under the microscope. For purposes of
scientific investigation, they are rarely looked at under light that
falls upon their surfaces, that is to say, by reflected light; for this
method can show nothing but details which are external and comparatively
unimportant. They are seen by light placed behind them so as to shine
through them, _i.e._ by transmitted light. If the object is not
extremely thin, it will shut out too much light, and thus it cannot be
clearly seen, therefore all objects, except the most minute, must be
divided into thin slices, technically known as "sections."
If we want to know not only the microscopic structure of organs, but
also their shape and position in the body, and their relations with
other parts, we must have every successive section carefully preserved,
and the whole row arranged in correct successive order; the physiologist
may often content himself with single sections; the zoologist must have
rows and rows of them. What a task this was, a quarter of a century ago,
for scientists who cut their sections by hand!
Let us, however, describe first the way in which objects are prepared
for section-cutting--whether by hand or by machine. It has already
been noticed that animal substances contain a quantity of water, and
therefore will not keep. The same circumstance renders them soft and
squashy, so that the sharpest razor in the world, in cutting a section,
must necessarily do more or less damage to the structure of the delicate
tissues. The water is held in the meshes of the tissues just as it is
held, for example, in the meshes of a sponge. Now, if we were dealing
with the sponge, we could get it to absorb any other fluid substance
besides water; we might choose one that would prevent decomposition; we
might choose one that would go harder by cooling; so as to change the
sponge into a strong solid block that could be knocked about without
sustaining any damage. This is exactly what we must do with our animal
tissue to prepare it for section-cutting; and the most convenient fluid
for the purpose is melted wax. But whereas we might take our sponge
out of water, squeeze it dry, and dip it straight into melted wax, we
can by no means do so with our animal tissues. For one thing they
usually cannot be squeezed, and where they can, they would of course be
irretrievably ruined by such a rough process. Even the transference of
the specimen from one fluid to another of very different qualities and
density, would deface the tissues. Cells would burst, or be squeezed out
of shape, and organs would be loosed from their right position by the
currents set up in all parts of the specimen, under such circumstances.
We must, therefore, try to get rid of the water by degrees. This may be
done by gradually adding alcohol, a fluid which may be diluted with
water in any proportion. We begin with a comparatively weak solution of
alcohol, say about fifty per cent., and immerse the specimen in this for
some little time. The time required depends somewhat upon the size of
the specimen; if a large one, a new fluid will take longer to filter
through it. Then we must change this solution of alcohol for stronger
ones, say seventy per cent. and ninety per cent. successively, and
finally to absolute alcohol. By this time the alcohol will have removed
almost nearly all trace of water from the specimen. The latter is now
nearly but not quite ready to be imbedded in melted wax; but first we
must soak it for a while in a fluid intermediate in thickness between
the alcohol and the wax, and capable of mixing in a friendly manner with
both. Then it goes into a bath of melted wax, and is kept for hours at a
stated temperature until the wax permeates it thoroughly. Then the
melted wax and the specimen along with it is poured into a little mould
and left to cool. The block of wax containing the specimen is cut down
to a quadrangular shape, and is now ready for section cutting. In old
days the block was placed in a stand, and successive sections were cut
from it by hand with a razor. But this process is much too slow for
modern days. Machines called microtomes (_i.e._ cutters of small parts)
have been invented, and of these there are several kinds--in all,
however, the razor is worked by machine and not by hand, so as to secure
steadiness and a uniform thinness of the sections. The old microtomes
threw off each section separately; but now matters are so arranged that
the wax of each section adheres to that of the next, and the whole
series of sections forms a continuous ribbon of thin wax. A large
specimen, affording a number of sections, thus results in a ribbon of
considerable length. Further processes are now required to fit the
sections for the microscope. The ribbon must be divided into successive
pieces of a length determined by that of the slides to be used. These
are mounted in order on the slides, steps are taken to melt away the
wax from the sections, the latter are covered with Canada Balsam
surmounted by a glass cover slip, and left for some time to dry. After
this they are ready for examination, and it is only now that the work
really begins. All that has gone before is mere handicraft; it is time
now for science to be called into play.
[Illustration: FIG. 47.--Sections of Embryo Chick, eight days old. A
slide mounted for microscopic examination, showing sections arranged in
ribbons.]
The sections must be compared with others of the same kind which have
been cut before. Do they entirely resemble these, or is there a
difference somewhere? Happy the man who finds that his sections
represent a fresh stage, perhaps older or younger than any that has been
seen before in the history of the particular animal which is under
investigation. Happier still the man who has succeeded in getting hold
of an animal which has not been described before. He will make haste to
write a full description of it, illustrated by drawings; to found a new
theory on it, if that can possibly be done; and to publish it to the
world. It will go all over the globe. To every country in Europe; to the
centres of learning in the United States; to universities in New Zealand
and Australia, and our other colonies; and perhaps even to "Far Japan."
When in his turn he receives publications from all countries, written in
all languages, he is in a position to realise the very great advantage
(referred to in an earlier page, p. 31) that results from the use of the
learned tongues, in the terminology of zoological science. For the
educated classes in all countries are equally acquainted with these; and
when half of a sentence consists of words of Greek or Latin derivation,
the labour of translation from a foreign tongue is necessarily greatly
lightened. To no writer is this advantage of so great importance as to
the Englishman, who is usually less familiar with the tongues of other
nations than his colleagues abroad. It will easily be understood that in
the world of zoology, there is no "predominance of the English-speaking
races." Far from it. German is the language which supplies the fullest
literature of every scientific subject; and in England even our
text-books are, for the most part, translated from the German. German,
in short, is to the seeker after Knowledge, what English is to the
seeker after Money.
Let us now pause a moment to consider how large a number of different
industries profit by the labour of the zoologist. First there is the
shipping trade; for, of course, all specimens from foreign lands are
brought by sea. The chemist supplies preservative substances, and
reagents used in the preparation of objects for the microscope. The
construction of microscopes is a profession in itself, and one which
employs many industries; for the making of a microscope includes not
only the work of the optician, but also that of the artificer in brass,
and of many other handicraftsmen. The glass-worker supplies "slides,"
that is to say, the thin pieces of glass upon which objects for the
microscope are placed, and "cover-slips," the little sheets of thinner
glass which are laid over them; and, besides these, the bottles in which
specimens are placed. Then comes the microtome, already spoken of, by
means of which sections for the microscope are cut; how many skilled
workmen have been engaged in the construction of its parts! Sheffield,
perhaps, has supplied the razor which it holds, as well as the
instruments for the dissection of the larger zoological specimens. We
have already spoken of the laboratory servants, and the
bone-articulators and skin-stuffers, who are personally and directly
employed by the zoologist; and of the artists and photographers who
depict his specimens, or perhaps copy his drawings. We must add to the
list of the zoologist's helpers, last, but not least, the printer who
"sets" the learned treatise in which the final result of his work is
usually embodied; and attendant on the work of the printer is that of
the bookbinder. With the bookseller the zoologist has but little to do;
the general public, even the reading public, has no knowledge whatever
of the writings of the zoological specialist. They are addressed to his
equals and co-workers, not to critics and reviewers. Their publication
is provided for, not by the law of supply and demand, but by the funds
of the learned societies and the universities. It is only occasionally
that a writer arises who is able and willing, like Huxley or Darwin, to
express himself in a book that the general public can read; and it is
only after a lifetime of detailed work, such as is understood only by
the specialist, that writers like these think it fitting to lay the
results of their labour before outsiders.
The librarian, finally, must not be forgotten, in making up our list of
the zoologist's helpers. The preservation and cataloguing of zoological
literature is obviously a task all the more important, because, as we
have already stated, zoological writings are not regulated by the law of
supply and demand. A very little paper, read to a very small meeting of
a learned society, and wholly ignored by the world at large, may
contain facts priceless to the world of science. It is on the accurate
and painstaking work of the librarian, who preserves and catalogues
small things as conscientiously as large ones, that we rely for the
completeness of our record of zoological knowledge. Such work has at all
times been carried on in the libraries of our universities; but at the
present time there are in existence libraries specially devoted to
zoological literature alone.
The museum, again, must not be forgotten, in which our man of learning
stores his specimens, duly labelled and arranged. Here, again, is a
staff of curators and sub-curators; and, under their direction, work for
various workmen, and for perhaps even a humble charwoman to dust the
shelves.
Turn now to another aspect of the zoologist's work--that of teaching. We
should think it very wrong to turn men loose on the world to practise in
the professions of law or medicine without a long and careful training
to fit them for their task. No less impossible is it for anyone to
become a man of science without a similar training; for the profession
of the man of science, whether zoologist, chemist, botanist, or expert
in whatever branch, if defined in plain English, is the profession of
seeking after knowledge of the order of things in which we live; and
what profession can be more important to the world than this? To attain
a scientific degree of any value, years of study are therefore required,
and a series of examinations tests--or is supposed to test--the success
of the student. Both the work of teaching and the work of examining must
be the tasks of the scientist who has attained a position of eminence
in the world of learning. The preparation of lectures, with their
accompanying illustrations of diagrams and lantern slides: the guiding
of classes engaged in the actual work of making acquaintance with animal
specimens--these are the labours of the great man who is at the head of
things. His task is carried out with the aid of junior helpers of his
own profession--the demonstrators, who "point out" detail after detail
of the work described in the lectures. Another helper, more esteemed by
the students than by the professor who teaches them, is the "coach" who
prepares them directly for their examinations. His aid, in the shape of
extra teaching, given at the last moment, will often secure for the
careless and inattentive pupil, better success than is the lot of the
painstaking and industrious one, who cannot afford to pay extra fees.
Few, however, of all the many pupils who crowd the lecture room of the
zoologist, will ever become zoologists themselves. A vast proportion of
them are students of medicine, of whom some knowledge of the subject is
required. Others are preparing to be schoolmasters or schoolmistresses,
and seek just such an amount of knowledge as they expect to find useful
in teaching pupils of their own. To the students who are preparing to be
doctors or teachers, circumstances often assign a limit--"thus far and
no farther"--when they would fain bring their knowledge to a higher
standard. But the time they have spent already has not been wasted. How
keen an observer of animal life is the country doctor! How often,
isolated from the world of learning, and ill-provided with books, he
finds in this his chief recreation! As for the schoolmaster, how is the
routine of school-work relaxed, and labour changed into pleasure, when
he lets his boys exchange grammar and Euclid for zoology, and the
lessons of the schoolroom for lessons in the fields!
The most important part, however, of a zoologist's work is not the
giving of instruction, but the labour of original research, to which we
have already alluded; not the mere communication of information, but the
task of adding to the general store of knowledge; not teaching, but
discovery. The work of the man of science is, in fact, within the limits
of his own department, the work of seeking after truth.
INDEX
A.
Acoelomata, 37.
Adaptation, 13.
Alternation of Generations, 57, 137.
Amoeba, 35, 45.
Amphibia, 152-154.
Ancestors, 40, 42.
Animalcule (minute animal), 49.
Anisopleura, 29.
Annelids, 72.
Annulosa, 69.
Ants, 92.
Appendages, 77.
Arachnida (spiders), 84.
Arthropoda, 33, 76.
Ascidians, 33, 44, 135.
Asexual reproduction, 55.
Atavistic variation, 27.
Azygo-branchiata, 29.
B.
Balanoglossus, 133, 143.
Barnacles, 79, 80.
Bees, 91.
Beetles, 95.
Bell Animalcule, 49.
Birds, 156.
Bivalve shell-fish, 23, 27, 107.
Body-cavity, 34, 37, 38.
Body-cavity (diagrams), 38, 139.
Body-rings, or "segments," 69.
Brachiopoda, 33, 43, 44, 117.
Bryozoa, 33, 44, 119.
Buds, 55.
Butterflies, 89, 93.
C.
Cat, fur of black, 160.
Cell, 11.
Cell-types, 49.
Cephalodiscus, 145.
Cephalopoda, 113.
Centipedes, 77.
Chætopoda, 71.
Chalk, 46.
Chordata, 33, 44, 135, 143-146.
Cilia, 42, 43, 48, 65.
Classes, 33.
Classification, 30.
Classification, tables of, 30, 44, 52, 62, 67, 75, 116, 118,
121, 134, 146, 164, 179.
Coelenterata, 33, 44, 53.
Coelomata, 37, 44.
Cockle, 111.
Colony, 57.
Corals, 59.
Corallines, 56, 58.
Corticata (or Infusoria), 47.
Crabs, 81.
Crocodile, 11.
Crustacea, 78-83.
Ctenophora, 60, 62.
D.
Degeneracy, 28, 172-180.
Development by metamorphosis (change of form), 41, 89.
Development, direct, 45.
Dicyemidæ, 34.
Diploblastic (two-layered), 34, 36.
Diploblastic larva, 41.
Duck-mole, 160.
E.
Earthworm, 74.
Earthworm, diagrammatic section of, to show position of body-cavity, 38.
Echinodermata, 33, 43, 44, 122.
Ectoderm, outer or skin-layer of adult animals and larvæ
(corresponding with the epiblast of embryos in the egg),
34, 37, 41, 139.
Eleutheroblasteæ (hydroid animals which throw off "free buds"), 56.
Embryology, 45.
Encrinites, 131.
Endoderm, inner or digestive layer of adult animals and larvæ
(corresponding with the hypoblast of embryos in the egg),
37, 41, 139.
Enteron, 36.
Environment, 26.
Errantia, or Wandering Annelids, 72.
Euthyneura, 100.
F.
Families, 33.
Fertility, 32.
Feathers, 157.
Feather-stars, 132.
Fishes, 150-152.
Flagella, 65.
Flat-fish, 23.
Foraminifera, 46.
Frogs, 38, 152.
G.
Galeodes, a spider-like animal, 85, 86.
Gasteropoda, 29, 98-107.
Gasteropoda, classification of, 29.
Gastræa, 40.
Gastrula, larva, 41, 150.
Genus, 32.
Gills, 45, 141, 149.
Grades, 34, 35-38.
Gregarina, 49.
H.
Heliozoa, 48.
Hemichordata (or Adelochorda), 33, 43, 145.
Hermit Crabs, 80.
Holostomata, 105.
Hybrid, 32.
Hydra, 36, 41, 54, 59.
I.
Infusoria 10, 47.
"Infusorial earth," 47.
Insects, true, 88-97.
J.
Jelly-fish, 57, 58.
K.
Kangaroo, 163.
L.
Lamellibranchiata, 107.
Lamp-shells, 119.
Land Animals, 166.
Larvæ, larval forms, 40, 41.
Larvæ of Brachiopods, 119.
Larvæ of Insects, 90.
Larvæ of Molluscs, 115.
Lancelet (Amphioxus), 41, 140, 149.
Leeches, 71.
Limpet, Common, 17, 19, 20, 29, 30.
Limpet, Semi-transparent, 15-20.
Liver-fluke, 71.
Lobsters, 80.
Lophophore, 117, 122.
Lustre, metallic, of feathers, 157.
M.
Mammalia, 160.
Man, 13, 26, 167-180.
Mantle (of bivalve molluscs), 108.
Marsupialia (or Metatheria), 161.
Marsupium or nursery-pocket, 161.
Mesoblast, 38.
Mesoderm or middle body-layer, 37, 61.
Metameric symmetry, 70.
Mesozoa, 35.
Metazoa, 35.
Microscope, 9, 10, 182.
Microscope, Sections for the, 182.
Microtome, 185.
Mites, 87.
Mollusca, 29.
Mollusca (classification of Gasteropod), 29.
Moths, 93.
Monoblastic, 34.
Moss-Corals, 33, 39, 119.
Mule, 32.
Mussel, Common, 103.
N.
Nematodes, 71.
Notochord, 135, 139, 145, 149, 151.
Nucleus, 35.
Nummulite, 46.
O.
Odontophore, 100.
Operculum (of univalve molluscs), 105.
Opossum, 161.
Orders, 33.
Orthonectidae, 34.
P.
Pelecypoda, 107.
Perforating gills (of vertebrates and other chordata), 142, 144.
Peripatus, 88.
Periwinkle, Common or Edible, 19, 26, 105.
Periwinkle, High-tide-mark (_L. rudis_) 19, 105, 114.
Periwinkle, Yellow, 19, 21, 23, 25, 30, 105.
"Persons" of a colony, 58.
Phoronis, 122.
Phylum, pl. phyla, 33.
Placophora, 113.
Planarian Worms, 37, 70.
Planula Larva, 41.
Platyhelminthes, 44, 71.
Polycystina, 47.
Polyzoa, 119.
Porifera, 33, 63, 68.
Protective Coloration, 15, 25.
Protophyta, 50.
Protoplasm, 35.
Prototheria, 161.
Protozoa, 33, 44, 45.
Pseudopodia, 36.
R.
Radial Symmetry, 53.
Radiata, 53.
Radiolarians, 47.
Rainbow Worm, 72, 159.
Reptiles, 154-156.
Rhabdopleura, 145.
Rhizopoda, 36, 46, 48.
Rodent, Teeth of, 163.
Rotifers, 76.
S.
Sand-hoppers, 83.
Sauropsida, 154.
Scales of fish, 142, 143.
Scallop, 107-112.
Scorpion, 87, 88.
Sex, 10.
Sea-Anemone, 54, 59.
Sea-Cucumbers, 129, 130.
Sea-Fan, 59.
Sea-Mats, 119.
Sea-Mouse, 72, 159.
Sea-Urchins, 23, 33, 122.
Shell-fish, 33.
Siphonostomata, 102, 106.
Skin of Vertebrates, 142.
Snail, 98, 114.
Snake-Stars, or Brittle-Stars, 128.
Species, 30.
Spiders, 84.
Spiny Ant-eater, 160.
Sponges, 33, 44, 63, 68.
Sponges, Parasitic, 68.
Starfishes, 127.
Streptoneura, 29, 100.
Symbiosis, 48.
T.
Teeth, 147, 163.
Tentacles (arms or feelers), 54.
Ticks, 87.
Trichina, 71.
Triploblastic (three-layered), 37.
Trochophora, 43.
Trochosphere larva, 42, 43, 72.
Tubicolous (tube-dwelling) Annelids, 72, 74.
Tunicata, 33, 44, 135.
Turbellaria, 70.
Two-layered animals, 34, 36.
U.
Unicellular animals, 11, 34, 35, 39, 44.
Univalve shell-fish, 98.
Urochordata, 145.
V.
Vacuole, contractile, 35.
Variation, 24, 26, 28, 32.
Varieties, 29.
Vermes, 33, 44, 68.
Vertebrae (joints of the backbone), 138, 139.
Vertebrata, 33, 44, 138.
W.
Water Animals, 166.
Wheel-ball larva, 42, 43.
White ants, 93.
Wood-lice, 83.
Worms, 33, 44, 68.
Z.
Zooids, 58.
Zoologists (_see below_).
Zoophyte, 53.
Zygobranchiata, 30.
Zoologists, names of--
Buffon, 11.
Caldwell, 160.
Chamisso, 137.
Cuvier, 54.
Darwin, 24, 76.
Dubois, Eugène, 168.
Forbes, 17.
Gadow, 157.
Gosse, P., 54.
Grant, Robert, 65.
Hæckel, 40, 168.
Hertwig, O., 50.
Huxley, 37, 78, 136, 154.
Kowalevsky, 136.
Landsborough, W., 109.
Lang, A., 39.
Linnaeus, 32, 68.
Leuckart, 71.
Morgan, Lloyd, 20.
Parker, T. J., 32.
Roberts, G., 21.
Romanes, G. J., 11.
Sharp, D., 92.
Sollas, 65.
Woodward, 109.
Transcriber's Note:
Obvious typographical errors have been corrected. Original published
spelling and hyphenation have been retained as they appear in the
original publication, including "debateable" and "cellless". A possible
missing "wall" has not been added to the caption for Fig. 5 ("--muscular
of intestine"; and reference to "the Italian poet" on Page 138 of the
original publication has been preserved. Where figures or tables cut
paragraphs, they were moved above or below the paragraph.
End of Project Gutenberg's Stories of the Universe: Animal Life, by B. Lindsay