PLATE VII
THE CUTTLE (1 and 2)
WE now come to the Molluscs, or Soft-bodied Animals, of which there are a very great many. Some of them live in shells, like the oyster and the whelk, and are often spoken of as “shell-fishes.” But they are not really fishes at all, for they have no bones as fishes have, and are made in quite a different way. And there are just a few of them which have no shells at all.
One of these is that very curious creature which we call the Cuttle. You may sometimes find it in the rock-pools, lurking in the crevices among the rocks, or hiding under the masses of sea-weeds which grow round the edges. It has a soft, white, bag-like body, and a big head, on which are two great staring black eyes. Just above these eyes eight long slender arms spring out; for cuttles keep their arms on their heads instead of on their bodies! And another arm which is even longer still, and is flattened out at the end into a kind of oval plate, hangs down on either side.
All these arms are set with rows of round suckers, which are so strong that if even a small cuttle catches hold of you, it will not be very easy to make him let go. So if you do happen to find a cuttle in a rock-pool it will be better to watch him in the water, without attempting to catch him.
Down in the middle of all these branching arms, just where they spring from the head, are two very curious organs. The first of these is the beak, which is very strong, very sharp, and a good deal hooked. In fact, it is rather like that of a parrot. The other consists of two tubes which run downwards into the head, lying side by side together like the barrels of a double-barrelled gun.
These tubes are called the “siphon,” and they are used for three purposes.
First of all, they are used for breathing. The cuttle breathes water by means of gills, like those of fishes, which lie inside the head; and the water passes down to them through one of the siphon tubes, and then goes out again through the other.
Next, they are used for swimming. When a cuttle wants to swim it gathers all its arms together in front of its head, fills both its siphon tubes with water, and then squirts their contents out again as hard as it can. The result is that two jets of water come rushing out of its head with such force that the surrounding water cannot give way fast enough before them. So they push the cuttle backwards so swiftly that if it were to dart across the pool you would hardly be able to follow its movements.
The third use of the siphon tubes is a very strange one indeed. Sometimes while you are looking at a cuttle in a rock-pool, the water all round it will suddenly become quite dark, just as if a quantity of ink had been poured into the pool. And so it has; for inside its body the cuttle has a bag which contains a quantity of a deep black liquid called “sepia.” This bag is surrounded by powerful muscles, and opens into the siphon tubes; so that when the animal contracts the muscles, the sepia is squirted out into the pool. It always does this if it is frightened; and under cover of the darkened water it nearly always succeeds in making its escape.
Inside its body the cuttle also has a very curious object which is generally called a “cuttle-bone.” It is not really a bone, however, but is made of almost pure chalk, and seems to act as a kind of support for the bodily organs.