Philosophical transactions, Vol. L. Part I. For the year 1757. / Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world.

by Various; Royal Society

In answer to this, let us examine the pliable structure of these bodies, and how wisely nature has defended such tender substances with a tough thin membranaceous covering, and we shall find, that the sea is calm enough often near the surface to give them time to grow, even in the strongest currents: but, without doubt, they are more liable to be destroyed in such agitated situations, than in the calm depths of the sea.

His second argument is, That finding polypes are not equally dispersed over the whole plant, how can they form it? and gives us an example, [Tab. VIII.] fig. 5. of a coralline, that is incrusted with many other corallines or polypes on the stem, but has none on the branches.

Here we plainly see the mistake: the Doctor looks for the tender part of the polype on the surface of the coralline, considering it as a plant; and indeed, if this was the case, he ought so to do; but he never once takes notice of the internal hollow structure of the stem, branches, and denticles of those bodies, to inform us whether he found an animal in those parts or no. This material point he seems not to have thought on; which is really the true point in controversy at present among gentlemen, who have not examined these bodies recent in sea-water.

His third argument is, That almost always one and the same coralline plant cherishes polypes of different kinds; and refers us to [Tab. VIII.] fig. 2. and 4.

In fig. 2. he gives us an elegant painting of a geniculated red conserva for a coralline, surrounded, as is very common, by many species of small corallines and escharas. And in fig. 4. he gives us a drawing of one of the tubular corallines, with the head of the animal at the top of it; the stem of this is incrusted with four different corallines and escharas, like the conserva fig 2.; and then he asks, which of these five polypes made the tubular coralline?

To give him some proof of the animal nature of this coralline, let him consult Ray's Synopsis, ed. 3. p. 34. n. 4. and there he will find one of his species, called adianti aurei minimi facie planta marina, taken notice of so long ago as the year 1713. by Dr. Lloyd, as a zoophyte, from its stem or tube's being full of a thick reddish liquor, rather resembling blood than the juice of a plant; which, upon pressing the stem, communicated with the little head at top.

His fourth argument is, That as upon one and the same coralline plant you shall find different kind of polypes; so, in different species of coralline, the same polypes; and, to confirm this, he quotes my Essay on Corallines; where I have remarked, that the polypes in the denticles of the setaceous or bristly coralline, Nº. 16. appear to be like those, that are on the lobster's horn coralline, Nº. 19. And to illustrate this, he observes, that bees and wasps always build their cells invariably the same; and that therefore these two corallines should be the same.

But herein he takes this matter wrong: he has considered, in all his observations, the heads of those parts of the polype, in which are the mouths, arms, or tentacula, which appear coming out of the cups, denticles, and at the ends of the tubes of the corallines, as so many whole and intire animals, without every observing, that the body of the animal is contained in the tubular part of the root, stem, and branches; and that these differ from one another widely both in size and shape, as he may plainly see in the two corallines he has instanced: for the more exact drawings of which, I shall refer him, viz. for the setaceous or bristly coralline, to my Plate, Nº. 38. the natural size of which is at fig. 4. and the magnified one at fig. D: this he will observe to have a small stem, and its branches disposed in a pinnated form: and for the lobster's-horn coralline, I shall refer him to Tab. xxii. of Vol. xlviii. of the Philosophical Transactions; where, at Nº. 3. the natural size is expressed, and at C the upper part of this coralline is drawn in proportion to the bristly coralline from the same magnifying glass; which shews the stem to be much larger, and surrounded by its branches growing in whorles at equal distances, not unlike the equisetum, or horse-tail plant; and yet the heads of this animal nearly resemble the other, only a little larger. Further, his comparison to bees and wasps, and their cells, is not conclusive: for these ramified, hollow, and denticulated bodies, called corallines, which we so frequently find dead on our shores, are properly skins of certain marine polypes, and not nests, as those constructed by these little winged animals are. And yet we find as great a regularity in the same species of these corallines, as when we compare two oak trees to one another, or two of Mr. Trembley's branched fresh-water polypes to one another.

He then proceeds to his fifth argument, That if corallines were formed by polypes, neither the polypes, nor even their cells, would ever fix on living animals, or any other bodies.

Here we may observe, that the consequence he draws doth not follow; for corallines may be formed or produced by certain species of polypes, and yet polypes of another species may be found adhering to other bodies, and even to animal bodies.