contracts itself, is much like a truncated cone, as in the engraving, with its basis fixed and strongly clinging to the rock. Its upper part is terminated with a hollow. This cone is often perpendicular to its basis: sometimes it lies in an oblique position to it, or the basis spreads itself irregularly; so that from a round it alters to an elliptical shape.

Sometimes it imitates pretty exactly the inclosing outleaves of anemonies, while

expressed by the other engraving. Indeed these animals alter their forms so often, that it would be difficult, perhaps, even impossible, to describe them exactly. One part of their body or limbs swells at times very considerably, at the expense of the rest. The figures and the particular observations will supply what is wanting here. With regard to their colours, they vary amazingly. Every hue of purple, green, brown, and violet, is to be seen blended together. A great number of them are of one uniform colour; while others are spotted either symmetrically, as in stripes, or in an irregular, but always pleasing manner. Most of them have round their basis a blue or white streak, broader or narrower, which produces a sort of ring. When many of these animals are put together at the bottom of a flattish and wide vessel, the whole appears as a bed of anemonies.

The sea anemonies of the second species are pretty nearly shaped out as those of the first,

but they are much larger. Mr. D. had some, kept in sea-water, that were 18 or 20 inches in circumference. Their cloak or outer skin is rough like shagreen, or full of little knobs: see the engraving. They remain in the sand, sticking to the loose stones in it, and stretch out their limbs to the top, in order to lay hold of their prey, as soon as it touches the superficies of the sand. The

flower of poppies is said to be the plague and distress of painters, to represent exactly the variety and brilliancy of its colours; the same may be said of the sea anemonies of this

larger species. The purest white, carmine, and ultramarine, would hardly be bright enough to paint them properly. The limbs of some of them are of a moderate or dim colour, at the same time that the cloak is made up of the brightest colours. The mouth is in the centre of the upper part: it is not always shaped in the same manner in other anemonies as it is seen here, or at least does not always appear to be so. This anemone has five rows of limbs. There are 10 in the innermost row; the like number in the second; 20 in the third; 30 in the fourth; and 80 in the fifth. When the animal is out of the water, and is squeezed, it spirts out water at the mouth and at several of its limbs at the same time; so that it imitates pretty well the play of water-works. When the limbs are drawn in closer together, they give it the look of a flower, especially of an anemone.

What first offered itself to Mr. D.'s observations, is what distinguishes these animals from plants, viz. progressive motion, by the help of which they can shift their place; the other determinate motions, by which they are enabled to lay hold of their prey; the means they make use of to defend themselves; their deglutition, digestion, evacuations, and, lastly, the propagation of their species, &c. What little he has had an opportunity to see of those functions appears sufficient to place these creatures in the class of spontaneous animals, rather than in the dark indeterminate list of zoophytes.

In May, 1772, he clipped all the limbs of a purple anemone of the first species. Soon after, these limbs began to bud out again. The 30th of July they were clipped a second time, and grew again in less than a month. Having cut them a third time, they had a third shooting out. The same experiment on a green anemone had the like success. It seems these reproductions might extend as far, or be as often repeated, as patience and curiosity would admit. Several experiments have convinced him that one single limb of these anemonies being cut off retains a power to fasten itself to any small body that is brought near it, either by its end, or by the side towards the end, but not by that part where the clipping was made.

These animals can live a whole year, and perhaps much longer, without any other food than what they chance to find disseminated in the sea-water. They do not want many motions to procure their food, besides stretching out their limbs, to receive such as comes within their reach; and they remain surrounded with muscles, &c. without laying hold of any of them. He has given anemonies some of these mus

cles alive, but with their shells closed, and about six lines in length. They were swallowed in that state; and 40, 50, and 60 hours after, the shells were thrown up at the mouth, empty and perfectly cleared, even from the small tendons which connect the fish to its shells. The anemonies swallow and digest small fish, and bits of larger fish, or of raw meat, when offered to them. When they cannot digest some of the food, they throw it up at the mouth, either whole or partly dissolved into a viscous liquor, which may, in some measure, be considered as their excrements.

Letter from the Sieur SEIGNETTE, Mayor of La Rochelle, and second perpetual Secretary of the Academy of that City.

THE experiment, of which I am going to give an account, was made in the presence of the Academy of this city. A live torpedo was placed on a table. Round another table stood five persons insulated. Two brass wires, each 13 feet long, were suspended to the ceiling by silken strings. One of these wires rested by one end on the wet napkin on which the fish lay; the other end was immersed in a basin full of water placed on the second table, on which stood four other basins likewise full of water. The first person put a finger of one hand in the basin in which the wire was immersed, and a finger of the other hand in the second basin. The second person put a finger of one hand in this last basin, and a finger of the other hand in the third, and so on successively, till the five persons communicated with one another by the water in the basins. The result of the experiment showed that the action of the torpedo is communicated by the same mediums as that of the electric fluid. The bodies which intercept the action of the one intercept, likewise, the action of the other. The effects produced by the torpedo resemble in every respect a weak electricity.

The effect of the animal was, in these experiments, transmitted through as great an extent and variety of conductors as almost at any time we had been able to obtain it, and the experiments included nearly all the points, in which its analogy with the effect of the Leyden phial had been observed.

The torpedo, on this occasion, dispensed only the distinct, instantaneous stroke, so well known by the name of the electric shock. That protracted but lighter sensation, that torpor or numbness which he at times induces, and from which he takes his name, was not then experienced from the animal; but it was imitated with artificial electricity, and shown to be pro

ducible by a quick consecution of minute shocks. This, in the torpedo, may perhaps be effected by the successive discharge of his numerous cylinders, in the nature of a running fire of musketry: the strong single shock may be his general volley. In the continued effect, as well as the instantaneous, his eyes, usually prominent, are withdrawn into their sockets. The same experiments, performed with the same torpedos, were, on the two succeeding days, repeated before numerous companies of the principal inhabitants of La Rochelle.

Several persons, forming as many distinct circuits, can be affected by one stroke of the animal, as well as when joined in a single circuit. For instance, four persons, touching separately his upper and lower surfaces, were all affected; two persons likewise, after the electricity had passed through a wire into a basin of water, transmitted it from thence, in two distinct channels, as their sensation convinced them, into another basin of water, whence it was conducted, probably in a united state, by a single wire. How much further the effect might be thus divided and subdivided into different channels, was not determined; but it was found to be proportionably weakened by multiplying these circuits, as it had been by extending the single circuit.

The organs themselves, when uncharged, appeared to be, not interiorly we might suppose, but rather exteriorly, conductors of a shock. An insulated person touching two torpedos, near each other, on a damp table, with his fingers placed, one on the organ of one fish, and another on the organ of the other, was sensible of shocks, sometimes delivered by one fish, and sometimes by the other, as might be discovered by the respective winking of their eyes. That the organs uncharged served some way or other as conductors was confirmed with artificial electricity in passing shocks by them, and in taking sparks from them when electrified. The electric effect was never perceived by us to be attended with any motion or alteration in the organs themselves, but was frequently accompanied with a little transient agitation along the cartilages which surround both organs.

The annexed figure represents the under surface of the female. a, An exposure, on flaying off the skin, of the right electric organ, which consists of white pliant columns, in a close, and for the most part hexagonal arrangement, giving the general appearance of a honeycomb in miniature. These columns have been sometimes denominated cylinders; but, hav ing no interstices, they are all angular, and chiefly six-cornered.

e,

b, The skin which covered the organ, showing, on its inner side, a hexagonal net-work. c, The nostrils in the form of a crescent. d, The mouth in a crescent contrary to that of the nostrils, furnished with several rows of very small hooked teeth. The branchial apertures, five on each side. fThe place of the heart. 9,9,9, The place of the two anterior transverse cartilages, which, passing one above and the other below the spine, support the diaphragm, and uniting towards their extremities, form on either side a kind of clavicle and scapula. h, h, The outward margin of the great lateral

fin. i, i, Its inner margin, confining with the electric organ. k, The articulation of the great lateral fin with the scapula. 7, The abdomen. m, m, m, The place of the posterior transverse cartilage which is single, united with the spine, and supports on each side the smaller lateral fins. n, n, n, n, The two smaller lateral fins. o, The anus. p, The fin of the tail.

Anatomical Observations on the Torpedo. By JOHN HUNTER, F.R.S.-[1773.]

THE electric organs of the torpedo are placed on each side of the cranium and gills, reaching from thence to the semicircular cartilages of each great fin, and extending longitudinally from the anterior extremity of the animal to the transverse cartilage, which divides the thorax from the abdomen; and within these limits they occupy the whole space between the skin of the upper and of the under surfaces: they are thickest at the edges near the centre of the fish, and become gradually thinner towards the extremities. Each electric organ, at its inner longitudinal edge, is unequally