Page:Hardwicke's Science-Gossip - Volume 1.pdf/194
ous flowering shrub in miniature, rising with a dark brown stem and diverging into numerous boughs, branches, and twigs, terminating in so many hydræ, wherein red and yellow intermixed afford a fine contrast to the whole (fig. 2). The glowing colours of the one, and the venerable aspect of the other, their intricate parts—often laden with prolific fruit, and their numberless tenants—all highly picturesque, are equally calculated to attract our admiration to the creative power displayed throughout the universe, and to sanction the character of this product as one of uncommon interest and beauty. A very fine specimen was recovered from rocks in a cavity in the bottom of the Frith of Forth, at about 150 feet from the surface. It was not, however, a tree, or shrub, or anything else, save in miniature, being, though recovered entire, only 7½ inches in height.
Fig. 3. Sickle Coralline.
Most interesting of all are the Protean changes of the Sertulariæ. A luxuriant specimen will at one moment resemble the richest of our floral productions in the flush of summer, and anon appear shorn of its flowers and foliage as in the winter season. The whole seems now still and lifeless, hastening to decay; but, left alone, it may in a few moments be found covered with innumerable animated blossoms issuing forth from their concealment to the light, which, after seeking their enjoyment in the fulness of display, again vanish in an instant into their retreats. The truth is, that a multitude of cells, some little more than a simple orifice, some shaped like a tooth, a cup, a flask, or a bell, with smooth or serrated lip, as the case may be, are placed on the stems, boughs, and branches of these Sertulariæ to afford retreats for its hydræ; and the specimen possessed of a hundred or a thousand different hydræ is also possessed of a hundred or a thousand different receptacles to shelter them.
The Sickle Coralline (Plumularia falcata) is a very common but elegant species, six inches or more in length, with slender branches, and twisting about itself in a spiral manner: along the branches are cells which contain the polypes (figs 3, 4). This elegant feathered coralline adheres to rocks and shells by little wrinkled tubes, and rises from
Fig. 4. Sickle Coralline, magnified.
them into erect stems, which are surrounded from bottom to top with pinnated branches; the smaller divisions of these have rows of little denticles or teeth, or cells, on the side, and bend inwards, as they become dry, in the form of a sickle.
The Sea Fir (Sertularia abietina) occurs on old empty shells. I see specimens of them at this moment flourishing on oyster-shells from Dorchester market-place. The sea fir is named abietina from its fancied resemblance to some species of fir (figs. 5, 6). It rises from nine to ten inches high, by a slightly waving stem, with branches on each side, so
Fig. 5. The Sea Fir.
that the extreme expanse is about three inches, the branches gradually shortened towards the apex. The sides of the whole stem and branches are clothed with cells, which swell in the middle, each enclosing its hydra. These animals are grey or white, protruding a long cylindrical neck and head, with about twenty-four tentacles.
The Lily Coralline (Sertularia rosacea) is a parasite on other zoophytes. A pure white, or faint-