A MEDUSOID.
From the edge of the "umbrella" there hangs a fringe of long, delicate hairs, rather like spiders' threads. These are fishing lines, yet much more deadly. They trail through the water, stretching far from the main part of the Jelly-fish; and any small creature unlucky enough to touch them is doomed.
Down each one of these threads there are minute cells, hundreds and hundreds to every thread; and in each cell there is a dart, coiled up like the spring of a watch. The tip of the dart is barbed like a fishhook. Now the cells are so made that they fly open when touched. The dart then leaps out and buries itself in the skin of the animal which touched the thread. Not only that, but the darts are poisoned, and soon kill the small creatures which they pierce.
You see now how this innocent-looking Jelly-fish gets its food. As it swims along, the threads touch the tiny living things in the sea, the darts pierce them and poison them. Of course these stinging darts are very, very small, much too small for our eyes to see.
Sometimes there are numbers of large brownish Jelly-fish in the sea, or washed up on the shore. If you are paddling or swimming, keep well away from them. Their poison darts are able to pierce through thin skin, and may cause you illness and great pain. Remember that the threads are very long; after you have passed the main body of the animal, you may still be in danger from the trailing threads.
We noticed these same poison darts when we were dealing with the flower-like animals, the Anemones. Only, in that case, they were so fine, so small, that they had no power to harm us, even though they entered our skin. You may remember that we called the Anemone a cousin of the Jelly-fish, for they both belong to the same lowly division of the Animal Kingdom.
Animals have queer ways of getting a living. Who would expect to find millions of poisoned darts in a Jelly-fish? Who would guess that these weapons are coiled up, ready to spring out at their prey? Men have made many weapons for killing, from the bow-and-arrow to the torpedo, but none of them is more wonderful than the weapon of the Jelly-fish.
EXERCISES
1. Where is the mouth of the Jelly-fish placed?
2. How does the Jelly-fish move through the water?
3. What is the food of the Jelly-fish?
4. How does it obtain its food?