Sea-Cucumbers
These are really relations of the starfishes, although they do not look in the least like them; for they closely resemble the vegetable after which they are named. In front of the slit at one end of the body, however, which serves as a mouth, there is a feathery tuft. This consists of delicate little tentacles, or feelers, by means of which the animal fishes for its food, and which can be drawn back inside the body when it is not hungry. And if it were not for this tuft one really might almost mistake the animal for a grayish-white cucumber.
We saw just now that the brittle-star breaks off its own rays at the slightest alarm. But the sea-cucumber, in this way, is even odder still, for if it eats anything which disagrees with it, as it sometimes does, it turns all its digestive organs out of its mouth, cuts them off, and allows them to float away! Then for three or four months it is very little else than a bag of empty skin, with just a slit at one end and a tuft in front of it. But at the end of that time new digestive organs begin to grow in the place of the old ones, and very soon the sea-cucumber is as perfect as ever!
Isn't that a remarkable way of curing indigestion?
Some of the sea-cucumbers grow to a very great size. One indeed, when fully grown, is nearly six feet long. And in China they are largely used as food, under the name of trepang, and are looked upon as a great dainty.
CHAPTER XXXVII
MOLLUSKS
The class of the mollusks is a very large one, for at least fifty thousand different kinds of these creatures are already known, while new ones are constantly being discovered. They may be described as soft-bodied, boneless animals, which are enclosed in a tough muscular skin called the mantle. And they are divided into five orders, the first of which includes the singular creatures known as squids, or cuttles.
You may sometimes find these animals hiding in the pools which are left among the rocks when the tide goes out; and you can recognize them at once by the long, fleshy tentacles, or arms, which spring from the upper part of the head. Some of them have ten of these arms, and are called decapods; the rest have only eight and are known as octopods. And the lower surface of each arm is furnished with a row of circular suckers, the grip of which is so powerful that the tentacle may even be torn in two without causing it to release its hold. Indeed, if quite a small cuttle were to seize you with one of its arms, you would not find it at all easy to make it let go again without killing it.