KERATOPHYTUM, in natural history, a species of GORGONIA.—The keratophyta are called the frutices coralloides, or sea shrubs; and generally known among naturalists by the different appellations of luo-phyta, lithocysta, and keratophyta; epithets tending to convey an idea of their composition, which at first view seems to consist partly of a woody or horny, partly of a stony or calcareous substance, variously disposed with respect to each other. Their general form approaches to that of shrubs, having a root-like base, by which they adhere to some solid support in the ocean; and a stem or trunk, and branches differently disposed; some rising up in one or more different twigs, subdivided into smaller and separate ramifications; while others have their smaller branches connected in such a manner, as to form a curious net-like structure: from this diversity of figure they borrow the names of sea-fans, sea-feathers, &c. The seeming fibres of the base are, in reality, small tubes, of which the whole shrub consists: these tubes run up longitudinally into the trunk, and are also circularly disposed about the centre of the trunk: the woody part, as naturalists have called it, thus formed, affords when burnt a strong smell like burning horn; whence some have called it the horny part. Upon this part is superinduced a kind of stony or calcareous coat, which covers both trunk and branches to their extremities. In this coat may be discovered regular orders or pores of cells; and viewed by the microscope, it always appears to be an organical body consisting of a regular congeries, like the cells in which animals have been formed or existed. Some of this kind of bodies have lost their calcareous covering by the violence of the waves and other accidents. In some specimens of an advanced growth, the calcareous tubes just mentioned send out little cells of animals of the polype kind, with proper openings to them all: these cells are diffused along the branches in some regular order, much in the same manner as they are in the corallines. From the cells the animals have been discovered extending themselves, as well to procure food, as materials for the increase of this surprising structure; and therefore there is no reason to doubt that they are animal productions.
A small sprig of the keratophyton stelliforme, or warty sea-fan, is represented in Plate CCL. The outside is covered with a crust full of little lumps
Kerckring lumps like warts; which, when dissolved in vinegar, discover the contracted bodies of polypes, like claws. Kermes C and C1 are two views of one of the warts magnified; C2, is the appearance of the polype when the cretaceous matter is dissolved; C3, represents the particles that compose the incrustation, magnified.—D, represents a sea-willow, or keratophyton dichotomum. On both edges of the flat branches are regular rows of little rising cells in the calcareous part, with small holes for an entrance to each. See CORALLINES.