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 order to form some idea, how these masses are increased and extended to the sizes we often meet with them, and where the same regularity of shape is preferred in the large, that we find in the small; we think it more than probable to suppose, that the species of polypes, that compose this coral, breed as we find all other polypes do: and this appears more evident to me, from what I have already discovered in many kinds of corallines (See Plate 38. of my Essay on Corallines), where the young polypes in some species are produced in the egg state, while others fall in great numbers from their matrices, completely formed, down to the roots of their parent corallines, either to begin a new race of the same species near them, or to increase the trunk, and extend the ramifications, of the plant-like figure which they just descended from.

From observing this method in nature, we shall the easier account for the progress of those generations of young testaceous polypes of this coral; which appear to us succeeding each other, and raising themselves up from the root or base, passing along the stem and branches, and covering the whole anew with their shelly cases: and in this their passage upwards we may observe, in the specimen before us, how they have involved and incrusted the small lateral branches of the former generation, so as almost to hide their appearance. From hence we may trace them extending themselves to the extremities of the upper branches, and there forming a new series of slender twigs, proportionable to those which they had just covered, still keeping order and exact symmetry in the whole structure.

The distinguishing character of this red coral, after we have considered its fistulous texture, is the knotty joints, of which it is composed: these appear more distinct, and are placed at a greater distance, in the smaller branches than the large; and, as we descend to the trunk, the traces of these inequalities but just appear.

From these protuberances, or knots, the lateral branches take their rise; and as these and the leading branches grow up together, they frequently inosculate at these joints, forming a kind of network, like what we observe in many of those species of keratophyta, which are called sea-fans.

The surface of this coral, when recent, is covered with a mealy friable matter, of a yellow colour, not unlike that of the true red coral, but much fuller of little raised starry cells. The figure of these cells is owing to the radiated position of the claws of the polypes.

Upon removing this friable matter, we observe, that the polypes of these cells have had a communication with a small hole or opening into one of the tubes, that lie immediately under it.

This frequent intervention of the openings of the small tubes, or their ramifications, between the sides of the larger ones, makes the latter appear more irregular, and not so parallel, as in the true red coral; where we find fewer stars; and, where those occur, we may observe it always alters the direction of the tubes.

I must further remark to you, that many of the tubes of this coral appear, thro' a magnifying glass, full of small holes, like those I have described in the keratophyton (Plate 26. Fig. G. p. 62. of my Essay on Corallines); and these holes will appear more distinctly to you, when you examine the half tubes, or broken irregular ones, on the stem and great branches of this coral.

Further, if you compare the transverse section, at the base of this coral, with a section of a common Rattan cane, they will both appear full of holes in the same regular order, and of nearly the same diameter: whereas the tubes, on the surface of the stem of this coral, look as irregular as so many holes pierced or eaten out by worms.

I hope by this time our ingenious botanical friends, whom we could not persuade to part with these beautiful sea-productions from the vegetable kingdom, are thoroughly convinced, that this mealy, friable, or calcarious covering, full of starry cells, which we are sure to find covering all the recent red corals and keratophyta, is not a mere blight of insects, common to the sea vegetables as well as land ones, which they have formerly insisted on; but that they will consider this covering, for the future, as proper and necessary for the well-being of these little animals, as they do at present hair and wool for beasts, feathers and down for birds, and scales and slime for fishes.