eight tentacula; others florid, and with twenty. They are frequently disgorged along with the half-digested food, thirty-eight appearing thus at a single litter. An embryo extracted artificially from the amputated tip of a tentaculum began to breed in fourteen months, and survived nearly five years. Monstrosities by excess are not uncommon among the young, one produced naturally consisting of two perfect bodies; and their parts, sustained by a single base, exhibited embryos in the tentacula at ten months, bred in twelve, and lived above five years. While one body was gorged with food, the other continued ravenous.

It is interesting to see the Actinia fed; and as they are very voracious, they are rarely unwilling to gratify their benefactors with a display of their swallowing powers. Their natural prey consists of the smaller Mollusca, Annelida, Star-fishes, Crustacea, and, in short, of any animals which they are able to seize and to retain. The tentacles have the same prehensile power as those of the Hydra,—a power which depends on the presence of projectile barbed weapons, ordinarly coiled in elastic cells. These organs are found in inconceivable multitudes imbedded in the tissues of the tentacles, of the lips, of the stomach, of the frilled ovarian bands, and especially, in some species, in long threads which are protruded from pores in the integument of the body.

The structure of these weapons is as follows :-Each consists of an oval or elliptical sac of transparent membrane, within which is seen a thread coiled up, and in some instances an oblong or lozenge-shaped chamber. At the

* Rep. Br. Assoc. 1834; and Edin. New Phil. Journ. xvii.

pleasure of the animal, or under the stimulus of pressure, the thread is shot forth from one end of the cell with great force, until it extends to a length from twice to fifty times that of the cell. When fully extended, it is seen that the thread is but a continuation of the cell itself; that when it was dormant, it was turned in ; and that in the process of expulsion, every part of its length has actually been turned inside out, like the finger of a glove. Sometimes the thread appears simple, but in those cases in which a chamber appeared within the cell, it is furnished with an armature of barbed threads, which after expulsion project from the sides of the thread in various directions. The propulsion of the thread is sufficiently forcible to enable it to enter the tissues of other animals, and the barbed structure enables the weapon to retain its hold in the flesh, which facts warrant the presumption that a highly poisonous fluid is at the same time injected, capable of arresting and destroying animal life. Some of the forms of these organs are represented in the accompanying figures.

In captivity, the process of taking food may be witnessed

by presenting to the Sea-Anemone any small shellfish or an atom of raw meat. When a tentacle comes into contact with it, it contracts forcibly, and the prey is thus dragged upon the oral disk, the surrounding tentacles arching over it. The lips instantly begin to protrude, stretching out towards the morsel, which they presently embrace, and gradually enclose, extending their volume, until they close over it, sucking it in as it were, and forcing it to disappear within the body. Digestion now takes place; and in the course of the next twenty-four hours the remains, such as the shell of the mollusk, or the hard parts of a little crab, are disgorged through the mouth, enveloped in a tenacious, slimy mucus.

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Though commonly the prey of the Actiniæ is small, it is not always so; the voracious creature occasionally mastering and swallowing a victim even much larger than itself, strange as such a proposition may sound. Dr Johnston has recorded from his own experience an example of this. "I had once brought me," he observes, specimen of Actinia crassicornis, that might have been originally two inches in diameter, and that had somehow contrived to swallow a valve of the great scallop (Pecten maximus), of the size of an ordinary saucer. The shell, fixed within the stomach, was so placed as to divide it completely into two halves, so that the body, stretched tensely over, had become thin and flattened like a pancake. All communication between the inferior portion of the stomach and the mouth was of course prevented, yet, instead of emaciating and dying of an atrophy, the animal had availed itself of what undoubtedly had been a very untoward accident, to increase its enjoyments and its

chance of double fare. A new mouth, furnished with two rows of numerous tentacula, was opened up on what had been the base, and led to the under stomach the individual had, indeed, become a sort of Siamese twin, but with greater intimacy and extent in its unions!"*

What may be the duration of life in these low forms of existence we know not, but recorded facts seem to warrant the belief that it is considerable. Sir John Dalyell stated in 1845, that one was then in vigorous health which had lived in his possession for a period of seventeen years.t They appear subject to few vicissitudes, and to enjoy a more than usual immunity from the attacks of other animals.

The reproductive energy is no less vigorous in these animals than in the Hydra; and similar experiments to those already described have been instituted on these with similar results. They have been variously maimed and cut into pieces, the fragments reproducing the parts lacking, and rapidly assuming a complete and normal condition.

We have at least fifty species of Sea-Anemones, including the allied genera, on the British coasts; and it is probable that they are even much more numerous than this, as new discoveries are constantly rewarding the close examination of any particular locality. Among them are two or three representatives of a form which is far more abundant in the tropical seas, where they have acquired renown above their fellows as "master-builders." The

*Brit. Zoophytes, i. 235.

We were informed, but a few days ago, that this notable individual still (September 1856) survives. From its appearance Sir John Dalyell considered that it was about seven years old when he procured it; it must now, therefore, have attained the age of thirty-five years.

structures of the Coral-worms very far excel the mightiest edifices of man. What was the impious project of Babel, what are the Pyramids of Egypt, compared with the coral reef of Australia-a barrier which extends almost without an interruption for a thousand miles!

The notion that the coral-rock was commenced in the fathomless depths of the ocean, and gradually reared to the surface, has been exploded by the discovery of Darwin, that the Coral-polypes cannot exist at a greater depth than some twenty or thirty fathoms. Our limited space will not permit us to do more than allude to his beautiful and ingenious theory, by which all the phenomena of coral formations are explained. It seems certain that every such structure must have been commenced on the inorganic rock; and the slow subsidence of these in many instances has produced the various forms of atolls, or ringislets enclosing lagoons, of barriers, and of fringing reefs.

Most intelligent persons are acquainted with the more common forms of Madrepores or Corals. Whether existing in massive, ramified, or laminated structures, they commonly consist of a light porous stone, studded with shallow pits, in which are seen thin perpendicular plates radiating towards a centre. Sometimes instead of pits and a radiating arrangement, the plates are set in rows in an involved and sinuated pattern. Now, during life, from amidst these plates rises up a gelatinous tissue bearing a mouth with protrusile lips, and an array of sensitive tentacles, all of which on alarm are contracted so as to disappear completely in the stony recesses, leaving nothing apparent but the white and apparently naked plates. Really, however, they are not naked, but are still invested with a