Page:Popular Science Monthly Volume 6.djvu/176

164 visitors often pick up tufts on the beach, and press them for sea-weeds. They are really the skeleton structures of a remarkable zoophyte, the Sertularia. We have an elegant species that grows upon the oyster, named Sertularia argentea, because it is often so white and glittering that it looks almost like silver. These I have found sometimes sixteen inches high, making the most exquisite gossamer-tree. But it is no tree or plant proper. Their substance is chiefly lime. They might well be called sea-ferns. When magnified, living specimens show what might be mistaken for little buds. If the microscopist is both skillful and patient, he will see a little starry object like a flower push itself out of one of these buds, which is really its case in which it lives. It may be seen waving its little life-petals about, catching food. I have not forgotten the delight experienced when I found out this fact for myself. Let the reader dwell a moment on Fig. 6. The Sertularia buoys up the oysters, as does the red sponge. And one may readily conceive how the animalcules must swarm in these gossamer-like forests or groves, so that not only the zooids but the oyster also enjoys the richness of the fishing-ground.

Everybody, that has seen any dredging in Long Island Sound, knows that lumps of matter made up entirely of small calcareous tubes abound there. These tubes are often found adhering to the oyster; in fact, these animals build them on the oyster's shell. Its name is Sabellaria vulgaris, so named by Prof. Verrill. The constructor and occupant is a worm, but, for all that, a creature of surpassing beauty. In company with this, another little being builds a tubular home on the oyster. It is a small serpula or serpent-shell, and is called by Verrill, Serpula dianthus, the pink serpula, because, when the little dweller therein projects its tiny florets, in form and color they suggest the pink of our gardens. But there is projected by the side of that pretty little pink, a curious, funnel-shaped process, that looks like the tiniest kind of a trumpet. We have watched those pretty creatures with their floral heads out fishing. Let the slightest jar be given, and the little thing takes alarm and instantly withdraws into its stony tube: first the floral head disappears, then the trumpetlike structure is drawn in, which actually plugs up the entrance. All this will be understood from Fig. 7, which shows a serpula. The spirorbis here figured is really a serpula, a tube coiled into a spiral. I have never seen the spirorbis growing on the oyster-shell, but have taken it from sea-weeds and Bryozoa thence obtained.

This natural plug, or stopper, is not without a smack of drollery. At least it has always impressed me as having in it a taste of the intensely utilitarian. And this reminds me that, in all their beauty, there is also a savor of the comical in the Bryozoa. Please to look at that Avicularlum in Fig. 5, 3. Is it not like the head of an eyeless bird? To see this "bird-head process" at work, one feels irresistibly that it is a real zooid, an individual among the Bryozoa, and Huxley