cular form; and the whole body is supported entirely by a set of upright bones or columns. On the outside of the shell is a prodigious number of sharp moveable spines, of a dull violet and greenish colour, curiously articulated, like ball or socket, with tubercles on the surface, and connected by strong ligaments to the skin or epidermis with which the shell is covered. The spines are the instruments by which the animal conveys itself at pleasure from one place to another; and by means of these it is enabled to move at the bottom of the water with great swiftIt generally employs those about the mouth for this purpose, keeping that opening downward; but it is also asserted to have the power of moving forward by turning on itself like a wheel*. When any thing alarms these animals, they immediately move all their spines toward it, and wait an attack, as an army of pikemen would with their weapons. The number of muscles, fibres, and other apparatus necessary to the proper management of these must be very great, and are exceedingly wonderful. So tenacious are the Sea-urchins of the vital principle, that, on opening one of them, it is no uncommon circumstance to observe the several parts of the broken shell move off in different directions. The antients, according to Oppian, gave credence to a circumstance much more wonderful than this:

Sea-urchins, who their native armour boast,
All stuck with spikes, prefer the sandy coast.

*Wallis, i. 393.

Should you with knives their prickly bodies wound,
Till the crude morsels pant upon the ground;

You may e'en then, when motion seems no more,
'Departing sense and fleeting life restore.

If in the sea the mangled parts you cast,
The conscious pieces to their fellows haste;
Again they aptly join, their whole compose,
Move as before, nor life nor vigour lose.

Between the spines, and disposed in a continued longitudinal series on the several divisions or regions of the shell, are an infinite number of very smail foramina, communicating with an equal number of tentacula placed above them. These are the instruments by which the creature affixes itself to any object, and stops its motions. They are possessed of a very high degree of contractile power, and are furnished at the extremities with an expansile part, which may be supposed to operate as a sphincter, or as the tail of a leech, in fastening the animals securely to rocks and other substances to which they choose to adhere.

The shell of this animal, when deprived of the spines, which often fall off after its death, is of a pale reddish tinge, and the tubercles on which the spines. are fixed appear like so many pearly protuberances on the surface.

At Marseilles, and in some other towns on the continent, this species is exposed for sale in the markets as oysters are with us, and is eaten boiled like an egg. It forms an article of food among the lower class of people on the sea-coasts of many parts of

THE BERNACLES*.

THESE shells are fixed at the base, and consist of more than two unequal and erect valves. The animal that inhabits them is similar to one inhabiting submarine rocks, that Linnæus has placed in the last order, under the name of Triton.

The two shells of this tribe that are best known are the Common Bernaclet, which is found adhering in vast numbers to rocks, and to oysters and other shell-fish; and the Goose Bernacle, so well known from the fables of its producing the Bernacle Goose.

The animals contained in these shells, as well as in those of all the other species, have twenty-four claws or tentacula, all joined in pairs near the bottom, and inserted in one common base. The twelve. longest stand somewhat erect and arched, arising from the back part of the animal; they appear like so many yellow curled feathers, clear, horny, and articulated every joint is furnished with two rows of hairs on the concave side. They are of use in catching prey, and the animals are continually extending and contracting these arched hairy claws, which

serve as a net.

*The Linnæan order of TESTACEOUS ANIMALS, OF SHELL-FISH, commences here.

+ Lepus Balanus of Linnæus. Lepus anatifera of Linnæus.

The twelve smallest are placed, six on each side, in the front of these. They are more pliable and more thickly set with hairs than the others, and seem to perform the office of hands.

The trunk or proboscis rises from the middle of the base of the larger claws, and is longer than any of them. This the animal moves with great agility in any direction; it is tubular, transparent, and composed of rings lessening gradually to the extremity, where it is surrounded with a circle of small bristles, which are likewise moveable. Along the inside of this transparent proboscis appears the spiral dark-coloured tongue, which is extended and contracted at pleasure.

The mouth, formed not unlike a contracted purse, is placed in front between the smaller claws, within the folds of which are six or eight horny laminæ or erect teeth. Under this lie the stomach, intestines, and tendons, by which the animal adheres to the shell*.

The Goose Bernacles consist each of five shells. They adhere in clusters to the bottoms of vessels and old timber, by means of tubes that in appearance are like some of the Corallinest.

THE PHOLAS TRIBE.

THE Pholas has a shell of two valves, that open widely at each end, with several lesser ones at the

* Ellis on Bernacles, Phil. Tran. vol. 1. p. 845.
+ See the account of the Bernacle Goose, in vol. ii.