Page:Popular Science Monthly Volume 7.djvu/15

This page has been validated.
SEA-ANEMONES.
5

They are tiny little things, clad with cilia, with which they move freely in the water for a little while, then settle on some stone, and give themselves up to a sedateness worthy the parent that gave them birth. It often happens that mother Anemone sends out her little ones in a very rough way into the world. In fact, they are introduced into actinian society sadly sans ceremonie. From the mesentery chambers are certain little ducts which open into the neck of the orifice, which we have called the mouth; and this orifice, it will be remembered is directly over the open stomach. So it sometimes happens that when one actinia is sending out a litter of her babies from the mouth, she, just at that very moment, takes a notion to empty her stomach of the indigested leavings of her last meal, so that these indigesta and two score innocents are evicted in a dreadfully execrable and unmeally-mouthed manner.

Fig. 3.—Vertical Section of Actinia.—a. Stomach-sac; b. Mesentery; c, Craspedum; d. Tentacle.

We must now notice a remarkable apparatus known as the lasso-cells. It has been repeatedly observed that an actinia has a stinging, or, as it is called, an urticating power over the tissue of other animals. Now, there are in different parts of the body of an actinia innumerable cells, from which, especially the cells on the tentacles, it can dart an invisible thread. The microscope can see it, and has made known its structure. In some species this delicate thread thus shot out is a marvelously-complex affair. It is coiled up, and when necessity urges, at the will of the animal, it is darted like a cord from a spring-trap. Now, this is just the simplest part of it; for, strange to say, when this thread is shot forth, just at the striking instant, out of the sides of this invisible thread other threads or snares spring, and these last are barbed. What a wonderful mechanism is this!

Let me invite you to a sight I have many times beheld. I have in captivity a hungry sea-flower. Knowing well what suits its palate, I take a delicate morsel like a pilule, and let it fall into the water. It descends upon the waving petals, or tentacula, on the point of one of which the pretty creature has caught it in an instant. How delicate the adjustment upon its more than fairy fingers! For a few moments it is