An Account of a Curious, Fleshy, Coral-Like Substance; In a Letter to Mr. Peter Collinson, F. R. S. from Dr. John Albert Schlosser, M. D. F. R. S. with Some Observations on It Communicated to Mr. Collinson by Mr. John Ellis, F. R. S.

The head is long and small. The extremity of the upper jaw runs out to a narrow point like the bill of a bird; on each side of which, a little distant from the extreme point, are two tubuli, or processes. As in the common eel, there are two fins at the gills. From the occiput all along the ridge of the back, small prickles are placed at little distances, resembling the teeth of a saw; these terminate at the origin of a membranous fin, rising about four inches from the tail, and is continued (as in the eel) along the lower part of the belly to the anus, at which place are also found two or three prickles. The colour of the head and back is blackish, variegated with dark-yellow spots. The lower belly white, changing gradually into a yellowish cast. The fin of the lower belly near to the anus is yellow, the other half spotted with black. The length of the fish described was eleven inches. LXI. An Account of a curious, fleshy, coral-like Substance; in a Letter to Mr. Peter Collinson, F. R. S. from Dr. John Albert Schloesser, M. D. F. R. S. with some Observations on it communicated to Mr. Collinson by Mr. John Ellis, F. R. S. Dear Sir, Read Jan. 22, 1756. I hired some fishermen to drudge for me in this harbour, in order to examine the small English coral, or corallium nostras of Ray's Synopsis, recent in the microscope. The first first time they hauled in the drudge, I discovered a most extraordinary sea-production surrounding the stem of an old *fucus teres*: it was of a hardish, but fleshy substance, and more than an inch thick, of a light brown or ash-colour, the whole surface covered over with bright yellow shining and star-like bodies, which induced me to believe it to be an undescribed species of alcyonium. I put it immediately into a bucket of sea-water, expecting every moment, that the polypes, which I thought to lodge in those little stars, would extend and shew themselves like those of the alcyonium, N° 2 of Ray's *Synopsis*, commonly called dead-man's hand; but after more than half an hour's fix'd attention, the vessel lying very quiet all the time, I did not perceive the least appearance of any polypes: upon which I brought them to shore in the sea-water, and then, by means of my microscope, I discovered every one of those stars to be a true animal, and much more beautiful than any polype, but quite of a different structure; which I shall now describe to you. Every one of those stars is composed of many thin hollow radii, of a pear-shape form, from five to twelve or more in number, all united intimately at their smaller end: every radius appears broad at the extreme part from the center, and a little convex in the middle of this raised broad part. When the animal is alive, there appears a circular little hole, which contracts and opens itself frequently. All the radii are of this structure; but their common center, which is formed by a combination of all the small converging extremities, exhibits an opening of a circular, oval, or oblong figure, forming a kind of rising rim like like a cup, which, when the animal is alive and at rest, contracts and expands itself to many different degrees, with great alertness and velocity, though sometimes it remains a great while expanded, or contracted. In all these holes, the central large one, as well as the smaller ones (which last I take to be the mouths of the animal) I could not perceive any tentacula, or claws, on the outside; but by looking into them very narrowly, I saw something like very tender little fibres moving at the bottom of their insides. By comparing and examining all the various pieces I had collected of this fleshy substance, with its shining stars, I observed, that the size and colour, as well as the very figure of these stars, varied greatly, but the structure of the leaf-like radii, and that of their mouths, and their motions, were perfectly the same, in every one individual. Many of these bodies I have found so thick and large as to resemble the great branch'd Madrepora coral, especially as they are generally to be met with covering and inclosing the stem and branches of this stiff, ramose fucus.—Thus far D. Schloßer. Fig. A (Tab. XIII.) expresses this alcyonium in its natural size, surrounding the stem and branches of a fucus. I have called it, *alcyonium carnosum asteriscis, radiis obtusis, ornatum*. Fig. B, part of a leaf of the common alga, or seagrass, with 4 of these starry figures on it. Fig. C, one of the stars magnified. Fig. D, represents the fucus, on which it grows, which I cannot find anywhere described. I have intitled it, in my collection of English fucus's, by the following descriptive name, *Fucus teres fruticosens*, I have had an opportunity lately of examining this curious, fleshy, coral-like figure in the microscope, and find, that all the interstices between the stars are fill'd with eggs of different sizes, each adhering by one end to a very fine capillary filament. The smallest eggs are globular, and as they advance in size, change to an oval figure; from thence they assume the shape of one of the radii of the stars. In several of these stars I have observed a smaller radius, as it were, endeavouring to get into the circle; and notwithstanding their seeming connection in the center as one animal, I believe I shall soon be able to shew you, in a drawing from the microscope, that each radius is a distinct animal by itself. I am, Dear Sir, Lawrence-lane, Jan. 22, 1756. Your most affectionate Friend, John Ellis. LXII. Two singular Cases of diseased Knee-joints successfully treated. The first by topical Applications; the second by Operation. By Mr. Joseph Warner, F. R. S. Surgeon to Guy's-Hospital. Read Jan. 22, 1756. Diseases of the larger joints of the extremities have always been look'd upon by surgeons of the greatest eminence in their pro-