JELLY FISHES.
The animals commonly known as Jelly Fishes are free-swimming Radiata; they were described by Cuvier and most succeeding naturalists under the name of Acalephæ, from a Greek word signifying “nettles,” because many of them produce a stinging sensation when they come in contact with the skin. Their name in several languages signifies “Sea Nettles.” The Acalephæ of Cuvier are now regarded as belonging to the same class as the Hydroid Polyps.
The common Medusa (Medusa amita), which may serve as an example of this group, is found in great abundance round our coasts; it is of a circular form, convex above, concave beneath, like an umbrella, the stick of which is represented by a thick stalk, containing the mouth and stomach, and terminated by four long arms for seizing the animal’s food. The skin of these, and of the body and its appendages generally is full of the thread-cells described as occurring in the Sea Anemones, and it is to these that the stinging power of the Medusæ is due. The motion of the Medusæ through the water is effected by the alternate expansion and contraction of its umbrella, which is slightly inclined in the direction towards which the creature is moving, and it is a most beautiful sight to look down upon a fleet of these animals, all advancing in the same direction at a depth of two or three feet in the water, as may often be seen in fine weather at the mouths of our rivers.
At first sight it may be thought that the Medusæ have but little in common with the Hydroid or any other Polyps, but it has been fully proved by late researches that the young animal produced from the egg of the Medusa is a regular Polyp, which adheres by its base, and obtains its food by the agency of a crown of tentacles surrounding its mouth; nay, it even propagates in this form by pushing out buds exactly in the manner described in the case of the fresh-water Hydra. In course of time, however, the body of this Polyp becomes elongated, and its surface is marked into rings, the grooves separating which gradually become deeper until the whole body breaks up into a number of saucer-like segments, each of which becomes a Medusa. How fully does this extraordinary mode of reproduction show that the wonders of the Creator are no less striking in the lowest than in the highest of his creatures, and that for all, from the highest to the lowest, the same prescient care has been exercised, the same goodness evinced. Verily, we may follow the pious example of the great Linnæus, and exclaim with the Psalmist, “O Lord, how manifold are thy works! in wisdom hast thou made them all.”
APPENDIX
OF
FABULOUS ANIMALS.
Our object in the previous pages has been to combine interest with amusement, and to present truth unmixed with fable. Yet considering that some fictitious animals are conventionally recognised in poetry and painting, we have thought it desirable to subjoin an account of them. The Sphinx, the Dragon, the Unicorn, Pegasus, and the Centaur, are so familiar to us, both in sculpture and fable, that some notice of these mythological creations seems indispensable.
