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inch from the point of the spinners, again unite, and form the cordage of the spider's web, each of which is composed of five thousand fibres.

THE WATER-SPIDER.

LOOKING into a large glass globe, filled with water, in which are immerged several portions of aquatic vegetables, some floating on the surface and some lying at the bottom, there may sometimes be seen amongst the blades of grass and bits of reed, a sort of purse, closely resembling in shape and size a pigeon's egg, but pierced transversely through the middle. It is filled with air, and perfectly closed, except in its lower part, where there is an aperture just sufficient for the ingress and egress of a very small spider. A strong and semi-transparent substance, resembling white gauze, forms the texture of the bell, firmly moored and anchored to the submerged plants by threads and cables, which hinder it from mounting to the surface.

M. Berthoud, a French naturalist, discovered them in the ponds of Gentilly, where they exist in great numbers; but their habits had long been known. He, however, examined them minutely, and we shall be guided in our account by his observations.

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Watch the lady of the mansion coming out of her retreat. Her length is about one-eighth of an inch, her body is brown, and upon the upper part of the back is drawn a dark patch, having four little dots on its centre. This spider lives under water, and yet requires air to breathe. Her Maker has taught her how to solve a problem which would have baffled the genius of Newton.

She swims on her back, and her abdomen is enveloped in a bubble of air, which, reflecting the prismatic colours, looks like transparent mother-o'-pearl. She then rises to the surface of the water, and elevates above it the lower portion of her body; for amongst the Arachnide the orifice of the organs of respiration is placed in the abdomen. Once on the surface, she breathes strongly, inhales as much air as she possibly can; then she gets beneath the water, and gives out gently the liquid particles with which her lungs are gorged to excess. The long, silky, clammy threads which cover her retain in its place around her the bubble with which she is surrounded. This done, she dives with precaution, and carries into her nest a provision of air, to replace what she had consumed.

When once ensconced in her nest, she lies in ambush, with her cunning little head lowered, watching for any prey that may chance to pass. Woe to the tiny worm that wriggles on the stalk near

her den! She darts forward, seizes him, and bears him off to her bed of impermeable gauze. Curious, indeed, is that little dwelling. While it was in process of making, it was naturally filled with water; but when once the work was ended, it became necessary to expel the water, and replace it by atmospheric air. To attain this end the spider had to make more than a hundred trips to the surface. Each bubble that she introduced mounted towards the top by its specific levity, displacing an equal quantity of water, which was forced out through the orifice below, until the bell contained nothing but air.

WATER-SPIDER, ENLARGED TWO-THIRDS.

The eggs are enveloped in a cocoon of silk; they are of a yellow orange colour, and may be easily perceived through the white transparent nest. In a short time the young begin to build for themselves, and may be seen swimming in the still water.

The water-spider every year rebuilds its nest very near the spot it has formerly occupied. It searches the water with astonishing precision, and is watchful over those water-plants in which are found the small aquatic insects which serve as its food. But how these little creatures can envelope the abdomen with an airbubble, and retain it till they enter their cells, is still a mystery which remains to be explained.

THE MASON SPIDER.*

NUMEROUS and various are the Mason Spiders; but the one of which we give engravings is found in the south of France. She usually selects for her nest a place bare of grass, sloping in such a manner as to carry off the water, and of a firm soil, without rocks or small stones. She digs a nest a foot or two in depth, and of a diameter equal throughout, sufficient to admit of her easily passing. She lines this with a tapestry of silk, glued to the walls. The door, which is circular, is constructed of many layers of earth kneaded and bound together with silk. Externally, it is flat and rough, corresponding to the earth around the entrance, for the purpose, no doubt, of concealment; on the inside it is convex, and tapestried thickly with a web of fine silk. The threads of this door-tapestry are prolonged, and strongly attached to the upper side of the entrance, forming an excellent hinge, which, when pushed open by the spider, shuts again by its own weight, without the aid of spring hinges. When the spider is at home, and her door forcibly opened, she pulls it strongly inwards, and even when half opened often snatches it out of the hand; but, when she is foiled in this, she retreats to the bottom of her nest, as the last re

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source.

THE MYGALE.+

E

F

A, THE NEST SHUT. B, THE NEST OPEN. C, THE
SPIDER (Mygale camentaria). D, THE EYES MAG-
NIFIED. E, F, PARTS OF THE FOOT AND CLAW
MAGNIFIED.

ANOTHER spider may be seen in Ceylon, of so great a size as nearly to cover with its legs an ordinary sized breakfast plate. Though it does not weave a broad web, like other spiders, it forms a comfortable mansion in the wall of a neglected building, the hollow of a tree, or the eaves of an overhanging stone. This it lines throughout with a tapestry of silk, of a tubular form, and a texture so exquisitely fine and closely woven that no moisture can penetrate it. The extremity of the tube is carried out to the entrance, where it expands into a little platform, stayed by braces to the nearest

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objects that afford a firm hold. In particular situations, where the entrance is exposed to the wind, the mygale, on the approach of the monsoon, extends the strong tissue above it, to serve as an awning to prevent the access of rain. And yet this skilfully-constructed silken dwelling serves no purpose in trapping or securing prey; no external disturbance of it tempts the creature to sally out and surprise the intruder; it is exclusively designed for the domestic luxury of the spider.

The animals of another family of this class are commonly called Scorpions. They are distinguished from other groups by having the abdomen articulated, and terminated by a curved spur at the extremity; the palpi

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are very large, and the terminal segment assumes the form of the lobster's claw, being in like manner provided with pincers; the stigmata are eight in number, and situated along the inferior and lateral part of the abdomen; on the under side of the thorax are two comb-like appendages. The number of the eyes varies from eight to twelve in different species.

The scorpions inhabit the hot countries of both hemispheres, live on the ground, conceal themselves under stones and other bodies, most commonly in ruins, dark and cool

THE SCORPION.

places, and even in houses. With their forceps they seize various insects, on which they feed after having pierced them with their sting.

The name of another extensive division or class + of animals established by modern naturalists, is derived from the Latin word annulus, a ring, because the body is always formed of a great number of rings. Their outer covering is soft and pliable; and their bodies, having no bony skeleton, are soft, and in general more or less of a cylindrical form.

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In this class are found some very remarkable creatures, with which, however, an acquaintance may easily be made. The under sides of every ledge, of every boulder, and of almost every pebble are studded with the twisting, creeping tubes of the Serpula; fine specimens of which are about one-fourth of an inch in diameter, each one being, like the shell of the oyster, the work of the little indweller. Watch the first of these which you can observe in a vivarium. The tube perhaps is closed, but now first comes forth its curious vermilion stopper, which has formed a beautiful and perfect defence; and then the breathing organs, an exquisite structure, adorned, it may be, with the richest tints of yellow, violet, azure, or crimson. That inverted cone-like body will be thrown off after a few weeks' service, only to be succeeded, however, by another, another, and another.

You wish, it may be, to examine the serpula more narrowly, and so, with a lens to your eye, you make an approach to the glass of the tank in

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+ Annelida.

which one has been placed. But, with the rapidity of a flash of lightning, he has withdrawn into his tube, as if conscious of danger; and only when he feels perfectly safe will he again be visible. Mr. Gosse has more minutely and happily described than any one else the wondrous mechanism of these two actions; and of this a succinct account may now be given. Behind the head, or what may be so termed, the sides of the body are cut into nipple-like feet, about seven pairs in all; these are perforated, and carry so many bundles of fine, elastic, horny bristles, like the hairs of a camel's-hair pencil, each pencil carrying from twenty to thirty bristles. A few of these are simple hairs, but the majority are of elaborate workmanship; for each one consists of a transparent, yellow, horny shaft, the extremity of which expands into a slightly enlarged knob. This knob is cleft into four points, three of which are minute, but the fourth is developed into a long, highlyelastic, and finely-pointed spear; and the pencils are acted on by appropriate muscles.

When the serpula would extrude its body from the tube, these organs push against the walls of the interior, which are lined, as you may see, with a delicate membrane. The opposite feet of one segment protrude the pencils of bristles, one on each side, the acute points of which penetrate and catch in the lining membrane; the segments behind this are now drawn up close, and extend their bristles: these catch in like manner; then an elongating movement takes place; the pencils of the anterior segments being now retracted, they yield to the movement, and are pushed forward, while the others are held firm by the resistance of their holding bristles; thus gradually the fore parts of the animal are exposed.

But this gradual process would not meet the need of a creature so sensitive to alarm when it wishes to retreat; a further provision is therefore necessary, and this Mr. Gosse has clearly and ably described. "If," he says, "we look at a serpula recently dead-which we may readily do, since it is the habit of most of these creatures to come out to die-we shall find, with a lens, a pale yellow line running along the upper surface of each part, transversely to the length of the body. This yellow line, which cannot be appreciated by the unassisted eye, is a muscular ribbon, on which stands up edge-wise a multitude of what I will call combs, or rather sub-triangular plates. The edge of each plate is cut very regularly into six teeth, which curve in one direction, and one other curved so as to face these. The combs stand side by side, parallel to each other, along the whole length of the ribbon, and there are muscular fibres seen affixed to the smaller end of every plate, which doubtless give it independent motion. I

EARTH-WORMS.

counted 136 plates on one ribbon; there are two ribbons on each thoracic segment, and there are seven such segments; hence we may compute the number of comb-like plates to be about 1,900, each of which is wielded by muscles at the will of the animal; while, as each plate carries seven teeth, there are between 13,000 and 14,000 teeth hooked into the lining membrane of the cell, when the animal chooses to descend." No wonder that, provided with so complicated and perfect an apparatus, he retreats so rapidly.

Another creature, the Terebella, forms a tube of bits of "beach," arranging them as regularly as rows of bricks, and strongly cementing them together. If one be placed in a vessel of water, and supplied with the requisite materials, it may be seen pursuing its task. Moving its head continually from side to side, it lengthens or shortens the thread-like rays that are placed there, and with a glutinous membrane for the base of its tube, piles on it piece after piece, which adhere immediately to it. In summer it will build a new house in about four hours; in winter an hour or two longer is required.

A friend of the writer's had one of these creatures in an aquarium, and wishing to help it in its structure, placed at its disposal some blue glass beads. These, however, it treated with neglect; but on their being broken small, it employed them in rearing its house.

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WORMS.

THE EARTH WORM.*

THIS animal presents externally a body composed of numerous narrow rings closely approximated to each other. In the night season, and at early morning, hundreds may be seen, though not one, unless they are disturbed either by moving the ground or pouring liquids into their holes, is to be found moving about in the day.

The worm-casts which so annoy the gardener by deforming his smooth-shaven lawns, are of no small importance to the agriculturist; and this despised creature is not only of great service in loosening the earth and rendering it permeable by air and water, but is also a most active and powerful agent in adding to the depth of the soil, and in covering comparatively barren tracts with a superficial layer of vegetable mould.

THE LEECH.+

THE outer investment of this creature may be described as a muscular tunic, with a coloured pigment on its surface, the whole being covered with a delicately thin cuticular membrane, lubricated with a mucous fluid.

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At its caudal extremity its fibres enter into the structure of a sucking disc, and some there assume a radiating, others a circular course. The same observation applies to their arrangement on the expansive, movable lips which encircle the oral aperture, and which also form another sucking disc, capable of being attached to objects over which the leech is proceeding.

The caudal and the oral suckers are the principal agents of locomotion on solid surfaces. The caudal sucker, for example, being fixed, the animal elongates its body to the utmost, and there fixes its oral sucker; this done, the caudal sucker is disengaged, the body drawn up, and the sucker fixed again, while the oral sucker is disengaged, the body again elongated, and this sucker once more attached, and so on alternately. By this simple process the leech can crawl along with considerable expedition, and even move up the smooth sides of a glass vessel, or it can there fix itself and rest. Destined to prey on the blood of animals, the mouth or disc-like lips may be compared to a cupping-glass; but it is one containing lancets for making, when fixed on the skin, three superficial yet

VOL. IV.

* Lumbricus terrestris.

+ Hirudo medicinalis.

333

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