earth-worm soon comes to the surface to empty its body. The rejected
matter is thoroughly mixed with the intestinal secretions, and is thus
rendered viscid. After becoming dried, it sets hard. When in a very
liquid state the earth is thrown out in little spurts, and when not so
liquid by a slow peristaltic movement of the intestine. It is not cast
indifferently on any side, but first on one and then on another, the
tail being used almost like a trowel. The little heap being formed the
worm seemingly avoids, for the sake of safety, the use of its tail,
the earthy matter being forced up through the previously deposited
soft mass. The mouth of the same burrow is used for this purpose for a
considerable time. When a worm comes to the surface to eject earth, the
tail protrudes, but when it collects leaves its head must protrude, and
thus worms must have the power of performing the difficult feat, as it
seems to us, of turning round in their closely-fitting burrows. Worms
do not always eject their castings upon the surface of the ground,
for when burrowing in newly turned-up earth, or between the stems of
banked-up plants, they deposit their castings in such places, and even
hollows beneath large stems lying on the surface of the ground are
filled up with their ejections. Old burrows collapse in time. The fine
earth voided by worms, if spread out uniformly, would form in many
places a layer of one-fifth of an inch in thickness. But this large
amount is not deposited within the old unused burrows. If the burrows
did not collapse, the whole ground would be first thickly riddled with
holes to the depth of ten inches or more, which in fifty years would
grow into a hollow, unsupported place ten inches deep.
Hardly any animal is more universally distributed than worms. The
earth-worm is found in all parts of the world, and some of the genera
have an enormous range. They inhabit the most isolated islands,
abounding in Iceland, and also being known to exist in the West Indies,
St. Helena, Madagascar, New Caledonia and Tahiti. Worms from Kergulen
Land in the Antarctic regions have been described by Ray Lankester,
and Darwin has reported them as being found in the Falkland Islands.
How they reach such isolated islands is quite unknown. They are easily
killed by salt water, and it does not seem likely that young worms or
their egg-capsules could be carried in earth adhering to the feet or
beaks of land-birds, especially to Kergulen Land, for it is not now
inhabited by any terrestrial bird.
We have seen that worms are found in nearly every part of the globe,
that they are very numerous, as many as 348,480 having been found in an
acre of rich ground in New Zealand, and that by the peculiar economy
of their nature they are fitted to accomplish a great deal of good
in the earth. They have played a more important part in the history
of the world than most persons would at first suppose. In many parts
of England, according to Darwin, a weight of more than ten tons of
dry earth annually passes through their bodies and is brought to the
surface in each acre of land, so that the entire superficial bed of
vegetable mould passes through their bodies in the course of every few
years; and in most parts of the forests and pasture-lands of Southern
Brazil, where several species of earth-worms abound, the whole soil to
a depth of a quarter of a metre looks as though it had passed through
the intestines of worms, even where scarcely any castings are to be
observed upon the surface. The upper crust is continually being eaten
and ejected by them, thus aiding the fertility of the soil, as well as
conveying water and air to the interior by the myriads of burrows which
they drill. The vast quantities of leaves that they drag into their
holes tend also to enrich the ground. Nor does their good end here.
They cover up seeds, undermine rocks, burying them up, and to their
labors is due the preservation of many ruins and ancient works of art.
Numerous old-time Roman villas have been discovered beneath the ground
in England, whose entombments were undoubtedly caused by the worms that
undermined them and deposited their castings upon the floors, till
finally, aided by other causes, they disappeared from sight.
When a wide, turf-covered expanse of earth is beheld, we would do well
to remember that its smoothness, upon which so much of its beauty
depends, is largely due to all the inequalities having been slowly
levelled by worms. That all the surface-mould of any such expanse has
passed, and will again pass, every few years through the bodies of
worms is a marvellous reflection, and one which should not be lightly
dismissed from the mind. The most ancient, as well as one of the most
valuable of man’s inventions, is the plough. But long before man
existed the land was in fact regularly ploughed, and still continues
to be ploughed, by earth-worms. No other animal has played such a part
in history as have these lowly-organized creatures. True it is that
corals, which are still lower in the scale of animals, have performed
more conspicuous work in the innumerable reefs and islands they have
built in the great oceans, but their work is confined to the tropical
zones, while that of the earth-worm is well-nigh universal. Verily it
is by the little things in life that the Creator has erected the most
stupendous monuments to show forth His infinite power and wisdom.
FIDDLER- AND HERMIT-CRABS.
Among our first acquaintances of the sea-shore are sure to be a number
of merry little sprites which do not seem to have yet mastered the
lesson of walking straight ahead. Their movements will be seen to be
in a direction at right angles to that towards which the head points.
It is a very interesting sight to watch these apparently one-sided
creatures hurrying off in their lateral progression towards their
burrows in the sand or mud, or in quest of food. Pass them, and you
will be surprised to see how quickly some of them will reverse their
motion, seemingly without so much as pausing to glance at their
pursuer, their machinery appearing to have given out at one end, thus
compelling them to reverse and travel back over their old courses.
These little Fiddler- or Calling-crabs, as they are termed, are the
most pronounced offenders against the commonly accepted rule of proper
walking. Scattered all over the salt marshes and mud-flats, at about
high-water mark, may be noted their burrows, which are about as large
as a thrust made by an umbrella point, and from which can be frequently
seen the little animal peeping forth, preparatory to making a sally.
At another part of the flat, where the noise of your footsteps has not
given signals of danger, hundreds of crabblings are busy with their
out-door occupations. Draw near to them, and away they scamper to their
dwellings, males and females intermingled promiscuously, the former
recognizable by the undue development of one of the claws, which is
carried transversely in front of the head. When the animal is provoked,
this claw is brandished in a somewhat menacing manner, which has been
likened by some to the pulling of a violin bow, and by others to the
action of beckoning or calling, and hence the names which have been
applied to these eccentric creatures.
Have you a desire for a more intimate knowledge of the animal, take him
up by the big claw, and you can now examine him without the least fear
of incurring the proofs of his displeasure. Two bead-like, compound
eyes, supported on long stalks, which can be readily withdrawn into the
protecting shield of the carapace, will be observed. From the manner
of this support, which allows of vision in almost every direction, the
name of stalk-eyed crustaceans has been given to the group in which
this structure is found. The two pairs of feelers, which you see in
front of the eyes, are known as antennæ and antennules. They are of
peculiar interest, for, aside from acting as feelers, they subserve
the functions of smelling and hearing, the auditory apparatus being
lodged in the base of the smaller pair. There are ten feet, and this
is a character of importance, as it is a feature distinctive of the
ten-footed, or decapod, crustaceans. At first sight it appears that the
animal is devoid of a tail, but if you turn him over upon his back you
will find a very short one tucked safely under the body. A comparison
of our study of this crab with that of the lobster or cray-fish will
show that the tail, or, more properly, the abdomen, is stretched out
beyond the body proper, and that the elongation is in proportion to the
length of the animal. Two distinct groups of ten-legged, stalk-eyed
crustaceans are thus recognized, namely: the short-tailed forms, or
crabs, and the opposite, or long-tailed forms, to which the lobster and
shrimp belong, the hermit-crabs constituting an intermediate type.
Two species of the Fiddler, considerably resembling each other in
color and ornamentation, are to be found upon our Atlantic Coast. The
more common form, _Gelasimus vocator_, has a smooth, shining carapace,
while that of _Gelasimus minax_ is finely granulated and in part
tuberculated, the back of both appearing impressed with a figure very
similar to the letter H. The latter, which appears to be a vegetable
feeder, is the larger, its burrows not infrequently measuring one and a
half inches in diameter. Estuarine regions, in close proximity to fresh
water, rather than the tidal flats, are its habitat, and, in truth, it
seems to be able to get along for weeks, and even months, without any
absolute need of salt water.
[Illustration: FIDDLER-CRABS.
Two Males Fighting for a Female.]
In the excavation of their homes the Fiddlers throw up the pellets of
moist earth by means of their anterior walking legs, depositing their
burden usually at some little distance from the mouth of the burrow.
As winter approaches, the domiciliary apertures are closed up, and the
famine of winter is spent in a state of torpidity.
With the advent of spring they come forth from their brumal retreats,
and soon concern themselves with the duties incident to the propagation
of their kind. Two males are often observed contending in the fiercest
manner for the possession of a female. They strike with the formidable
claw most powerful blows, and I have often seen an opponent so
completely claw-locked as to be unutterly unable to make any determined
resistance. These contests last a long while, and finally conclude
with the complete vanquishment of one or the other of the fighting
parties, one or both sustaining at times some severe injury as the loss
of an eye-peduncle or the joint of a limb. All the while the battle
is waging, the female is a silent, passive spectator, and generally
allies herself with the successful competitor for her affections. Even
during the summer season, when the cares of brood-raising no longer
command and enslave the attention of the female, these combats are
still indulged in by the males, growing out of, as it would seem, the
lingering smarts of old animosities festering in the memory. While
these carcinological lords of the sea-side are eminently fitted for
the sparring business, the whole physiognomy of their smaller, weaker
partners bespeaks a life in which broils can have no part, a life
devoted to peaceful and domestic pursuits.
Differing widely in structure and habits from the Calling-crabs,
and affecting watery situations near the shore, are to be found the
Hermit-crabs. These sprightly little animals, which are usually of
small size, and have truly habits of their own, that stamp them at
once as being original and distinctive, are a source of never-failing
delight to the student of nature. They derive their name, as is well
known, from the seclusion into which they cast themselves as the
inhabitants of the shells of other animals, but it is probably not
generally known, however, that the rights of tenantry are oftentimes
exercised in the most arbitrary manner. Not always satisfied with
a dead shell, the Hermit-crab has been seen to raid upon a living
possessor and attempt to drag him from his home, in which operation the
assailant is often assisted by a number of his fellows, each bearing
with him his castle as defensive armor. True, the attack is probably
made in many instances for the purpose of getting possession of the
enemy as well as his belongings, and, however this may be, forcible
possession is by them considered no misdemeanor.
The body of the Hermit-crab, in the greater number of species, is
unprovided with a carapace, and, being soft and liable to injury,
the animal is compelled to seek shelter usually in a snail-shell,
winding himself about the coils, to the inner extremity of which he
attaches himself by his modified posterior feet. So securely is he
now intrenched that it is only with difficulty he can be withdrawn,
retracting himself as he does further and further within cover of the
shell. A sudden fracture of the apex of the shell, under which appears
to be the most delicate part of the animal’s body, will generally
effect a speedy dislodgment, the frightened Crab dropping from the
aperture.
With his progressive development in size the Hermit requires frequent
changes of abode. His methods in securing a new habitation are among
the most interesting of his life. He is very circumspect in his
movements, and will make several reconnoissances before he is fully
satisfied with the conditions of his prospective home, retiring after
each visit to the old shell.
[Illustration: Copyright 1900 by A. R. DUGMORE.
CRAB WAITING FOR FOOD UNDER A ROCK.
From a photograph taken through water.]
Like many bipeds, he has his first of May, and so he goes
house-hunting. He finds a shell. Will it do? He examines it within,
feelingly if not courteously, to see whether it is to let. Satisfied on
this point, he turns it over, then turns it round, to know if it will
suit, the weight of the house being quite an item in the reckoning to
one who is to carry it upon his back. All things being right, his mind
is made up to move, and quickly, too, at that, lest he miss his chance
through some more active fellow house-hunter who is on the alert. Out
comes the body from the old house, and pop it goes into the new. The
resolution to move, the surrender of the old house, and the occupancy
of the new, were all effected within a fraction of a second of time.
[Illustration: WARTY HERMIT-CRABS.
One at Home, the Other House-Hunting.]
But the matter does not always go on pleasantly. Two house-hunters may
find the same tenement. Should they both desire it, then comes the tug
of war. Dwell together they neither can nor will. Recourse is had to
battle, in which the stronger proves his claim right by the rule of
might. In these encounters terrible mutilations quite often occur.
As an offset to all this bad feeling and bloodshed, it is a sad sight
to see the little Hermit when his time comes to die. However droll
his career may have been, he is now very grave, for he knows he must
part with life and all its joys and pleasures. Who can explain the
strange fact? The poor little fellow comes out of his house to die.
Yes, to die. To us humans home is the only fit place to die in, but
to Eupagurus it has no attractions at this solemn time. Poor fellow!
With a sad look and a melancholy movement he quits of his own will the
house for which he fought so well. Those feelers that often stood out
so provokingly, and that were quite as often poked into everybody’s
business, now lie prone and harmless; the eyes have lost their
pertness, and dead, stone dead, the houseless Hermit lies upon that
moss-covered rock.
There are two species of Hermit-crab occurring on our coast, which
are readily distinguishable from each other by their size and the
difference in the shape of the big claw. _Eupagurus pollicaris_, the
Warty Hermit, is the larger species. He inhabits the shells of the big
Naticas and the Fulgurs, and can be easily recognized by his coarse,
broad claws, which close up in great part the aperture of the shell
which he occupies. In the more common form, _Eupagurus longicarpus_,
which seldom attains a length exceeding an inch, the legs are all much
elongated, giving the animal a very slender appearance.
FUNNEL-WEB BUILDER.
Simple nests and tubes are all the majority of spiders construct for
their homes. The larger and better known webs for catching insects are
made by comparatively few species. He who is astir in the grass-fields
on damp summer mornings, will everywhere see innumerous flat webs, from
an inch or two to a foot in diameter, which weather-wise folks consider
prognostic of a fair day. These webs may always be found upon the grass
at the proper season, but only become visible from a distance when
the dew is upon them, making the earth appear as covered by an almost
continuous carpet of silk.
By far the greater number of these nests is of the form which is termed
funnel-webs, which consist of a concave sheet of silk, constituted of
strong threads, crossed by finer ones, which the author spins with the
long hind-spinnerets, swinging them from side to side, and laying down
a band of threads at each stroke, the many hundred threads extending in
all directions to the supporting spears of grass. The web is so close
and tight that the footsteps of the spider can be distinctly heard by
the attentive, listening ear as she runs hither and thither over its
scarcely bending surface. At one side of the web is a tube, leading
down among the grass-stems, which serves as a hiding-place for the
owner of the web. Here, at the top, and just out of sight, the spider
ordinarily stands, waiting for something to light upon the web, when
she eagerly rushes out, seizing the prey unluckily caught and carrying
it into her tube to eat. If too formidable an insect comes upon the
web, she turns herself round, beating a precipitate retreat out of the
lower end of her funnel and soon is lost beneath the mesh of enveloping
and interlacing grasses.
Where favorably located, these webs remain through the entire season,
and are enlarged, as the spider grows, by additions on the outer edges,
and are supported by threads running up into the neighboring plants.
Sometimes the webs are built in close proximity to a stone partially
imbedded in the earth, the bottom of the funnel opening slightly
underneath the stone, which secures to the spider a convenient harbor
in case of threatening danger.
Agalenidæ, as our funnel-web weavers are called, are long-legged, brown
spiders, in which the head part of the cephalo-thorax is higher than
the thoracic part, and distinctly separated from it by grooves or marks
at the sides. The eyes are usually in two rows, but in Agalena the
middle eyes of both rows are much higher than the others. The feet have
three claws, and the posterior pairs of spinnerets are two-jointed and
usually longer than the others. _Agalena nævia_, the technical name of
our Common Grass Spider, abounds in all parts of the United States, but
its very commonness is the principal reason why it is so little known
except by the trained naturalist, its very familiarity leading the
average man and woman to look upon it with contempt.
[Illustration: AGALENA AND HER FUNNEL-WEB.
House-Fly, Caught in the Toils, Becomes a Victim.]
Persons unfamiliar with spiders find it difficult to distinguish the
young from the old, and male from female. This is caused, in part, by
the great differences between different ages and sexes of the same
spider, on account of which they are supposed to belong to distinct
species. The adult males and females, however, are easily distinguished
from each other, and from the young, by the complete development of
organs peculiar to each sex, the palpal organs on the ends of the palpi
in the males, and the epigynum, a hard swollen place just in front
of the opening of the ovaries in the females. Usually the males are
smaller than their partners, and have, in proportion to their size,
smaller abdomens and longer legs. They are generally darker colored,
especially on the head and front part of the body, and markings which
are distinct in the female coalesce and become darker in the male. In
most species these differences are not very great, but in some, Argiope
and Nephila for examples, where the males are about one-tenth as large
as the females, one would hardly suppose, without other evidence, that
the males and females had any relationship to each other. The palpal
organs and the epigynum are sexual characters which do not attain their
functional value until after the last moult has been effected.
Spiders are naturally very selfish creatures. Their chief concern in
life seems to be the gratification of their desires for food. They are
eminently unsocial, the sexes preferring to live solitary lives. It is
only when actuated by amatory influences that the females will tolerate
their weaker lords, and in some instances it is only by stratagem
and agility that the latter are able to accomplish the fulfilment of
the law of their being, the females by their ugly, vicious tempers
resisting to the utmost. In the case of Agalena the male is the
stronger of the two. He, at the proper time, when the reproductive
cells are matured, takes the female in his powerful mandibles, lays
her gently on one side, and inserts one of his palpi, whose little
sacs had previously been filled with the fecundating discharge, into
the epigynum underneath. After a time, necessarily brief, he rises on
tiptoe, turns her around and over, so that she comfortably lies on the
other side, her head being in the opposite direction, and inserts the
other palpus. All through the operation the female lies as though she
was dead. The ends of nature being served, the sexes separate, the male
returning to the solitary life he previously led, while the female
busies herself in providing for the duties of maternity.
The eggs becoming mature, the latter proceeds to make a little web
and lays them in it, practising the utmost care. She now covers them
over with silk, which she weaves into a cocoon, where the young remain
some time after they are hatched. Seldom is the laying seen, for it
generally happens in the night-time, or in retired places. Often, in
confinement, the spider refuses to lay at all. An egg of a spider, like
that of any other animal, is a cell which separates from the body of
the female, and subsequently unites with one or more cells that have
separated from the body of the male. This process of union, termed
fertilization, doubtless takes place when the eggs have attained their
full size and are about to be laid. After being laid and hardened it is
a very easy matter to watch their development. All that is necessary
to be done is to cover the egg to be examined with oil, alcohol or any
liquid that will wet it, for this tends to make the shell transparent.
Eggs laid in summer are ready to hatch in a fortnight, while those
laid in autumn develop slowly all through the winter. A day or two are
occupied in hatching. When the time has arrived the shell, or more
properly the skin, cracks along the lines between the legs, and comes
off in rags, and the spider slowly stretches itself and creeps about.
Pale and soft it appears, and devoid of hairs or spines, but its feet
are armed with small claws. In two or three days it gets rid of another
skin, and begins to assume a spider-like appearance, the eyes becoming
dark-colored, the thoracic marks growing more distinct, and a dark
stripe appearing across the edge of each segment of the abdomen. The
hairs are now long, but few in number, and arranged in rows across the
abdomen and along the middle of the thorax. Before the next moult they
usually forsake the cocoon, and live together for a short time in a web
spun in common. Where larger broods of young spiders live together,
they soon show cannibal-like qualities, and if kept in confinement one
or two out of a cocoon-full may be raised without recourse to any other
food.