The four round spots on the top of the body, sometimes white and sometimes red in color, are spaces in the body, and they open into the central stomach. The circles of these chambers are lined with ciliate membrane, and in some places it is arranged in folds, and in them the eggs or ova form. Little oval or roundish things, like pins’ heads are they: they burst forth and pass out of the stomach, and then through the canal into the four lobes hanging down like pouting lips. Here they rest a while until a little grown, and they start out on their journey of life in the autumn time as little oval or long things made up of cells, the outside ones having movable hairs also on them. Totally unlike the parent, the tiny offspring floats off with the tide and does a little work in moving itself with its hairy covering. Sooner or later this minute thing, which is called a planula, settles on a stone or piece of sea-weed, and begins to grow. First of all its outer skin is formed into a hollow on the top, a kind of basin-shaped cavity being produced. This is the future stomach. Then some little projections grow around the hollow, and stick out in the water like so many rays, and they increase in number and length very rapidly. Under this shape the creature has been described as a hydra or a polype, and it really resembles a small sea-anemone with very long and slender tentacles. But the internal anatomy differs. The creature is all stomach and tentacles, and it grows by catching small prey. All the elaborate tissues of the jelly-fish are absent and the creature can not move. It is this curious condition of life that brings the jelly-fish tribe within notice of a seashore observer, for those little hydras live in some places at low-water mark. The knowledge that the hydra was the child of the jelly-fish was obtained many years ago by a Scotch and by a Scandinavian naturalist. It was known that some small kinds of jelly-fish which were kept in sea-water in an aquarium disappeared altogether in the late autumn. Then it was noticed that there were many very small things with tentacles, on the sides of the glass, which had not been noticed before. And at last the curious discovery was made that these hydras or planulas reproduced jelly-fish the next year. This is a very strange story, and the course of nature’s proceeding is, that when food has become scarce and the boisterous waves would become fatal to the delicate Medusa, it shall lay eggs which produce creatures that can settle down out of the way of the rush of water, and that require but little food. Then in the next year when food is in plenty, the progeny separate into jelly-fish like the parent. The hydras or progeny have no power of laying eggs; they digest and produce the creature that shall lay eggs. The Scandinavian naturalists and Germans called this “alternate generation,” and named the hydra the nurse of the jelly-fishes. This is the method by which most of the jelly-fish, which may be