THERE is an old aphorism which says that "all life comes from an egg"-omne vivum ex ovo; but this, like a good many other old aphorisms, is only a convenient and attractive way of stating a falsehood. It is very true that almost all animals, from man down to the mollusk, pass through the egg stage at an early period of their existence; but we purpose to show our readers in this article that there are others which appear to be sometimes exempted from the common lot of their kind, and which indeed come into the world in such curious fashions that we may almost say of them, in the words of Topsey, that they "never were born; 'spect they growed."

To begin with, what is an egg? According to the popular idea, it is an oval-shaped body, consisting of a hard, thin shell inclosing a whitish substance called the albumen, within which is a yellowish matter called the yolk; it is the embryo form of the young of birds and some other animals, which finally emerge from the shell after the egg has been acted upon for some time by the heat of the parent's body. Now this definition may do well enough as a loose description of the more familiar varieties of eggs, but it will not do for all. It will perhaps surprise the unscientific reader to be told that every animal whatever produces eggs. A "mare's nest" is the popular expression of a myth, an absurdity; but mare's eggs are no myths; they are just as real as hen's eggs; only we never see them, because they are hatched in the parent's body before

the young colt is brought forth. The same is true of the eggs of all the other quadrupeds and of viviparous animals in general.

An egg, therefore, like the seed of a plant, is the germ from which the embryo is developed. It may have a shell, or it may not; it may be comparatively large, like birds' eggs, or it may be so small as to be with difficulty discerned by the naked eye. When it is first formed it is simply an aggregation of fluid matter, very minute in size, and exceedingly simple in structure. By degrees this fluid is transformed into the small particles or granules which form the yolk; the yolk shapes itself into a multitude of cells-little microscopic bodies consisting of an external membrane, or cell-wall, and of an inner nucleus, which may be either solid or fluid; and in due process of time a number of cells combine and form a living being. The albumen, or "white," is, like the shell, an accessory. It performs important functions in the development of the young from the germ, but we will not stop to explain them here; the true egg is the yolk. In the lowest forms of animal life the egg is a mere cell, with a light spot in one part of it, and the creature which is developed from it is almost as simple in structure as the egg itself.

The ordinary mode of reproduction, as we have already said, is by the for mation of an egg in the body of the parent, from which the young may be hatched either before or after they are brought into the world. But there are certain of the lower orders of animals which sometimes multiply and

shell of a mollusk. An anemone is always found attached to the shell which the crab inhabits, and is so placed that its fringed mouth comes just below the mouth of the crab. Whatever food comes within reach of either animal can, therefore, be shared in common. The crab is so far from objecting to this community of goods that he seems unhappy without his companion. Though he is a hermit, he is not exempt from the common lot of housekeepers; he submits every now and then to the trouble of moving day.

Mr. Gosse observed one in the act of changing houses. No sooner had he taken possession of the new shell than he began removing the anemone from the old one, running his claw under it to separate it from the shell, and then bringing it to the new house, where, having placed it in its customary position, he held it down until it had attached itself, and now and then pressed it closer, or gave it a pat to hasten the process. In another instance, observed by Mr. Holdsworth, the crab, after vainly trying for more than an hour to remove his companion anemone, deserted his new quarters and went back to the old, rather than submit to a separation.

The anemone, for all that it is so delicate and graceful in appearance, is a gluttonous little beast, eats raw meat in the aquarium, and when upon its native coast sucks mussels and cockles out of their shells. Queer compound of plant and animal in appearance, its natural kingdom seems still more doubtful than ever if we watch it while it is undergoing certain processes of reproduction. It does indeed generally produce its young by maternal gestation; eggs are formed in the cavity that surrounds its stomach, and at the proper time the young swim out of the parent's mouth. But it has other modes of propagation, one of which is almost exactly like the process of raising plants from suckers. Very often you

may see, growing out of the lower part of the body of the anemone, and as a general thing near the edge of the basal disc by which it attaches itself to the shell or rock, little rounded protuberances, like buds; well, they are buds—the buds of young memones. In a short time six small tentacles make their appearance on the top of each bud. A minute oblong aperture opens in the midst of them. A digestive cavity is formed. The curious internal structure of the animal (which we have not space here to describe) is gradually developed. The bud becomes elongated and enlarged every way. The tentacles multiply; the small aperture grows into a mouth; and finally the young anemone drops off from its parent and floats away to shift for itself. Professor Clark has seen as many as twenty thus detach themselves in the course of a single month. This is the process of generation by budding or gemmation, of which we spoke on a previous page.

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But we have not yet exhausted the list of wonders displayed by this extraordinary plant-animal. We have seen that it has at least two ways of being born; what will our readers say when we assure them that it has not only two but four? The remaining two both come under the head of what is called voluntary self-division. of them is strikingly like the propaga tion of plants by cuttings. Little pieces break off from the anemone at the base and float away. For a long time they give no sign of life; but when they have recovered, so to speak, from the shock of separation, they begin to shoot out their tentacles and grow up into perfect individuals. The fourth method of generation is still more wonderful. Now and then you find an anemone whose upper disc is contracted in a peculiar manner at opposite sides. The contraction increases until the disc loses its circular form and presents the shape of the figure 8. The two halves of the 8 next separate, and you

have an anemone with two mouths, each surrounded by its own set of tentacles. Then the processes of constriction and separation continue all down the body of the animal from summit to base, and the result is two perfect anemones, each complete in its organization. It is well that the lower orders of creatures have none of the laws of inheritance and primogeniture that bother mankind, or such irregular methods of coming into the world might breed a great deal of trouble among them. Here, for instance, you have two anemones, which we will call A and B, formed by the splitting asunder of a single individual; what relation are they to each other? Are they brother and sister or parent and child? And if the latter, how is any one to decide which is the parent? Then suppose A raises offspring in the usual way from eggs, what relation are these young to B? Are they sisters, or nieces, or grandchildren?

Let us now look at another animal, the stentor, or trumpet-animalcule. This is a minute infusorian, very common in ponds and ditches, where it forms colonies on the stems of waterweeds or submerged sticks and stones. Some of the varieties have a deep blue color, and a settlement of them looks very much like a patch of blue mould. The stentor is shaped like a little tube, about one-sixteenth of an inch in length, spread out at the upper end like a trumpet, and tapering at the lower almost to a point. When it has fixed upon a place of abode, it constructs a domicile, consisting of a gelatinous sheath, perhaps half as high as itself. It lives inside this sheath, with its smaller extremity attached to the bottom of it, and its wide, funnelshaped end projecting above the top. When disturbed it retreats into the house and shrinks into a globular mass. The disc of the trumpet end is not perfectly regular; on one side the edge turns inward so as to form a notch, and curls upon itself in a spiral form. Within this spiral is the mouth,

and a long funnel-shaped throat reaches from it to the digestive cavity. Opposite the mouth there is a globular cavity, from which a tube extends to the lower extremity of the body. The cavity seems to perform the functions of a heart, and the tube takes the place of veins and arteries. Once in threequarters of a minute this heart-like organ contracts and forces the fluid which it contains into the tube; the latter in its turn, after expanding very sensibly to receive the flow, contracts and returns it to the heart.

The stentor propagates by budding, like the anemone. The first change that takes place is a division of this contractile vesicle into two distinct organs at about mid-height of the body, the lower portion developing a globular cavity like.the upper one. Soon after this a shallow pit opens in the side of the stentor, in a line with the new vesicle. This pit is the future mouth. A throat or œsophagus is next fashioned; and all being ready for the accommodation of the new animal the process of division begins, and goes on so rapidly that it is all done in about two hours.

A still more curious animal, in some respects, than either of those we have just mentioned is the hydra, one of the simplest of the zoophytes. To all intents and purposes it is nothing but a narrow sack, about half an inch in length, open at one end, where the mouth is situated, and attaching itself by the other to pond-lilies, duck-weeds, or stones on the margins of lakes. Around the mouth it has from five to eight slender tentacles, which are used as feelers and for the purpose of seizing the food. What it does with its food after it has swallowed it is, strange as the statement may sound, a question to which naturalists have not yet found a satisfactory answer; for the hydra has no digestive organs, and its stomach is merely a pouch formed by the folding in of the outer skin. It has no glands, no mucous membrane, no appliances of any sort for the performance of the chemical process

which we call digestion. You may turn a hydra inside out and it will get along just as well as it did before, and swallow its prey with just as good an appetite. The French naturalist Trembley was the first to notice this remarkable fact. With the blunt end of a small needle he pushed the bottom of the sack through the body and out at the mouth, just as you would invert a stocking. He found that the animal righted itself as soon as it was left alone; so he repeated the operation, and this time made use of persuasion, in the form of a bristle run crosswise through the body, to induce the victim to remain inside out. In the course of a few days its interior and exterior departments were thoroughly reorganized, and it ate as if nothing had happened. Trembley next undertook to engraft one individual upon another! For this purpose he crammed the tail of one deep down into the cavity of another, and, in order to hold them in their position, stuck a bristle through both. What was his surprise to find them, some hours afterward, still spitted upon the bristle, but hanging side by side instead of one within the other! How they had got into such a position he could not imagine. He arranged another pair, and on watching them the mystery was solved. The inner one first drew up its tail and pushed it out through the hole in the outer one's side where the bristle entered. Then it pulled its head out after the tail, and sliding along the spit completely freed itself from its companion. This it repeated as often as the experiment was tried in that way. It then occurred to M. Trembley that if the inner hydra were turned inside out, so as to bring the stomachs of the two animals in contact, union would take place more readily; and so it proved. The little creatures seemed much pleased with the arrangement, and made no attempt to escape. In a short time they were united as one body, and enjoyed their food in common.

It was perhaps only natural to ex

pect that animals which care so little about their individuality that two specimens can be turned into one, would be equally ready to multiply themselves by the simple process of being cut to pieces. In other words, you may make one hydra out of two, or two out of one, just as you please. M. Trembley divided them in every conceivable manner. He cut them in two, and, instead of dying, one half shot out a new head and the other developed a new tail. He sliced them into thin rings, and each slice swam away, got itself a set of tentacles, and grew into a perfectly formed individual. He split them into thin longitudinal strips, and each strip reproduced what was wanting to give it a complete body. Some he split only part way down from the mouth, and the result was a hydra, like the fabled monster, with many heads. The famous cat with nine lives is nothing to these little zoophytes. They seem sublimely indifferent not only to the most fearful wounds, but even to disease and, we are tempted to add, decomposition itself. A part of the body decays, and the hydra simply drops it off, like a worn-out garment, and lives on as if it had lost nothing.

If it can do all this, we need not wonder that it can reproduce its kind by budding. Indeed, after we have seen a living creature split itself up into a dozen distinct individuals any other process of generation must seem tame by comparison. At certain seasons of the year very few hydras can be found which have not one, two, or three young ones growing out of their bodies. The budding begins in the form of a simple bulging from the side of the parent, something like a wart. This is

gradually elongated, and after a time tentacles sprout from the free end, and a mouth is formed. The young is now in a condition to seek its own prey. Its independence is finally accomplished by a constriction of the base of the new body at the point where it is attached to the old stock, until finally it cuts itself off. Before