2. Actinia, or Sea-Anemone.

The beautiful genus thus denominated from its resemblance to the flower of this name when its feelers or tentacles are expanded, is characterised by having an oblong body, of an extensile and expansile nature, and adhering by the base to rocks and other marine substances. The mouth is situated in the centre of the upper part or disc, and is surrounded by very numerous, soft, extensile feelers, or arms, spreading in the manner of rays, and disposed in a single, double, or triple series, according to the different species. The Actiniæ are very common on the rocks of most of the European coasts: when in their contracted state, they have the appearance of inanimate rounded masses of coloured pulp, or flesh; and when expanded, they greatly resemble the appearance of an expanded polypetalous flower, particularly those of the anemone and ranunculus tribe. One of the most common British species is the actinia varia*, found on most of our coasts, and varying ad infinitum in its colours, being either red, olive, green, of different shades, and either plain or variously spotted: its principal character, and which distinguishes it in whatever variety of general colour it may happen to appear, consists in a row of short bead-like prominences, surrounding the external row of tentacula: these bead-like processes are invariably of a bright blue colour. The actinia varia in general, measures about two inches in diameter, at the base, but is occasionally seen of a larger size..

A more beautiful species is, however, found on our own coasts; generally imbedding itself in the sand, instead of adhering to rocks; it is called the actinia crassicornis, and is distinguished by its red colour, and roughish external surface; while the central or middle part, when expanded, is white, most elegantly marked near the base of the tentacula, with numerous carmine-coloured streaks; the tentacula themselves, being of a pearl-colour, and of a much thicker or more swelled appearance than in most other species. The actinia crassicornis often measures four, five, or even six inches in diameter when in its expanded state.

The actiniæ, or sea-anemonies, are naturally very voracious animals, preying not only on the softer sea-animals, but on such as are

* Act, Mesembryanthemum. Ellis. Gmel. Syst. Nat.

guarded by a shelly defence; they swallow various kinds of univalve shell-fish, the smaller kind of crabs, and other animals; and when they have absorbed the juices of their prey, they reject the shell or other integument by the mouth. When kept in vessels of sea-water, which may be easily practised, they seem to require no particular nutriment, absorbing a sufficient quantity of animal gluten, from the sea-water itself, for all the purposes of nutrition. In this confined state they do not grow or increase in size, though they frequently produce a numerous offspring, being of a very prolific nature, and viviparous. The young are produced of various sizes, from that of a pin's head to that of half an inch in diameter, and to the number of five, ten, or more at a birth. As these animals are allied to the polype tribe in some degree, they partake of their qualities, and will reproduce many of their organs, when either purposely or accidentally mutilated.

3. Asterias, or Star-Fish.

Most of these are of a stellated or radiated shape, as their name imports; the rays differing in number in different species, from five to ten or twelve. The most curious of the whole tribe, is A. Caput Medusa, of Linnæus, or Medusa's head star-fish. It grows to a large extent, measuring more than two feet in diameter when the limbs are fully extended. This very extraordinary animal is first divided into five equidistant, jointed processes, each of which is soon subdivided into two other smaller ones; and each of these, at a somewhat farther distance, into two others, still smaller; this mode of regular subdivision, being continued to a vast extent, and in the most beautiful gradation of minuteness, till at length the number of extreme ramifications amounts to several thousands. By this Imost curious structure, the animal becomes, as it were, a kind of living net; and is capable of catching such creatures as are destined for its prey, by the sudden contraction of all its innumerable ramifications, and thus the object is secured beyond all power of escape. Examples of this animal, well worthy of notice, are to be found in the British, and were formerly in the Leverian Museum.

The sea-stars, in general, have a very considerable degree of reproductive power; and if injured by accidental violence, or if one or more of the limbs be cut or torn off, the animal will in time be furnished with new ones. They wander about the ocean in quest of

prey, more particularly near the shores; and feed not only on the softer sea-animals, but on the smaller shell-fish. Their mouth, which, as before observed, is situated beneath, is armed with hard and sharp teeth, resembling a kind of spines, and converging towards the centre of the mouth, and differing in number in the different species. We should not omit to observe, that the curious species last mentioned, the Medusa's head star-fish, is chiefly confined to the Indian seas, but is sometimes found in those of Europe. Those who may wish for a particular description of the anatomy of the star-fishes, may consult the observations of Reaumur on this subject, published in the Memoirs of the French Academy.

[Shaw.

SECTION V.

Testaceous Worms, or those possessing Shells.

We have already seen that these consist of three divisions, according to the number of valves or pieces of which the entire covering consists; and hence these divisions are denominated univalves, bivalves, and multivalves. We shall select a few of the most curious instances of each.

Among the UNIVALVES, or those possessing only a single shell, the most common perhaps are the snail, (helix,) and the perriwinkle, (turbo,) kinds. Among the most interesting are the papernautilus, the pearl-nautilus, and the ship-worm. The animals inhabiting this description of shells, are, for the most part, the slug and the cuttle-fish.

1. Paper Nautilus.

Argonauta Argo.-LINN.

"Among the principal miracles of nature," says Pliny, " is the. animal called nautilus, or pompilos. It ascends to the surface of the sea in a supine posture, and gradually raising itself up, forces out, by means of its tube, all the water from the shell, in order that it may swim the more readily; then throwing back the two foremost arms, it displays between them a membrane of wonderful tenuity, which acts as a sail, while with the remaining arms it rows itself along; the tail in the middle acting as a helm to direct its