head.

Many people think that the dark upper part of a flat fish is the back, and the white under part is the stomach. We have seen, however, that this is not so, for flat fish lie on one side.

For the rest of its life the Plaice will remain flat, with two eyes looking up, and a twisted head. But its colour alters. The side on which it lies is white; the upper side becomes brown and speckled, dotted over with red marks. This is a good disguise. Its enemies cannot distinguish the Plaice from the pebbles and sand around it. They might swim over it, and yet not see the thin, flat, brownish body pressed down on the bed of the sea.

Also, these flat fish have a wonderful way of changing colour. Put them on light sand, and they become lightish. Put them on dark sand and pebbles, and they soon match it by becoming brown and mottled. This is a most useful dodge where so many enemies abound, all swifter in the water than the slow-swimming flat fish.

If you look for flat fish in an aquarium, you will not easily see them. Now and again one will swim up, with a wavy motion of its body. On settling again, it shuffles and flaps about, works itself into the sand, hiding its edges well under, and then, hey presto! it is gone! If the flat fish are so hard to find in a tank, you may be sure it would be impossible to find them on the sea bed. They are poor swimmers, but perfect hiders.

As far as we can tell, they feed on other living creatures. The ocean floor is a huge dining table for them, where they find very mixed dinners. They eat small fish, sand-worms, shell-fish, Shrimps and young Crabs. The Plaice has strong, blunt teeth in its throat, and is well able to grind up the shells of Cockles and other molluscs, swallowing the juicy contents.

Now we have seen that the Plaice is first a floating egg, and then a tiny transparent "round" fish. It sinks to the sea bed, lies on one side, and becomes a flat fish like its parents.

These little baby flat fish, not much larger than your thumb-nail, crowd in the shallow, sandy parts of the sea near the coast. There they often end their lives in the shrimp-trawl, as we have already noticed.

After leaving this "infants' school" the Plaice, and other small flat fish, go to deeper water. There they feed and grow fat. Our fishermen know where to find them. Indeed, these special fishing grounds are so well known that flat fish are scarcer than they used to be. Some kinds are much too dear ever to be seen on the poor man's table.

There is a special net for catching flat fish, called a trawl. This is a large net, dragged over the bed of the sea by ropes, or steel wire, attached to the sailing vessel or steam trawler. The net is kept open under water by means of beams or boards.

When the flat fish are disturbed, they rise a foot or two from the sea floor, and are then swept into the gaping mouth of the deadly trawl. Once in, there is no escape. There they remain, pressed together, until the net is hauled up and emptied.

EXERCISES

1. Give the names of five kinds of flat fish. 2. How does the Plaice escape its enemies in the sea? 3. What is the food of the Plaice? 4. How are flat fish usually caught for the market?

LESSON III

SEALS

There are many different kinds of Seal; the family is a large one, but all have one thing in common--the fish-like body, with toes joined together by a web. Anyone who has seen the diving power of a Seal, and its wonderful way in the water, will agree that the "flippers" of the Seal are as useful as the fins of the fish.

In fact, the flipper beats the fin, for the Seal earns his dinner by chasing and catching fish. He slips through the water with perfect ease, and seizes the darting fish in their own home. The Seal is nearly always hungry, but so wonderfully quick that his hunting is made easy for him.

It is quite another matter on land, where his best pace is a waddle and a shuffle; but his life is in the wide sea, where he can feed and sleep as easily as other mammals can on land.

Seals are easily tamed, and soon become fond of their owners. Some fishermen once caught a baby Seal, which they gave to a boy, knowing his love of animals. The strange baby soon made itself at home, and loved to lie in the warmth of the kitchen fire. It knew the voice of its young master, and would follow him like a dog.

The older it grew, the more milk and fish it needed each day. At last, this food was not to be easily obtained, and so the boy had to get rid of his pet. He rowed out to sea, taking the Seal, and let it free in the ocean to fend for itself; but the Seal would not leave him; it swam swiftly round the boat, calling pitifully. Needless to say, it was taken back again, and well cared for.

Seals have even been trained to catch fish for their owners. Being docile by nature, and having larger brains than most animals, they can be taught. Perhaps you have seen Sea-lions performing surprising tricks, showing clearly how intelligent these fish-like creatures really are. The Sea-lions at the London "Zoo" are not specially trained. But they are clever enough to teach themselves, especially when rewarded by a few extra fish. They know well the voice of their keeper, and clap with their flippers to let him know that feeding--time is near; and in many other amusing ways they prove their intelligence.

You have noticed, perhaps, that these Sea-lions can shuffle along on their hind flippers, which are turned forward under the body. The real Seals, however, cannot do this. Their hind limbs, so wonderful in the water, are merely dragged behind the body on land. "Sealskin" should be called "Sea-lion-skin," to be exact; for it is the Sea-lions, not the true Seals, which men kill and rob of their lovely warm coats.

The giant of the Seal family is the Sea-elephant; a big lumbering fellow, with a most peculiar nose. Of course this gives him his name, though it is not much like the trunk of the real elephant. It is just the baggy skin of his nose, a foot long, which hangs down past his mouth.

When the Sea-elephant is angry or excited, this loose nose of his becomes filled with air, and bulges out. Our coloured picture shows you Mr. Sea-elephant, full grown; his wife and children have ordinary seal noses. Perhaps we should say wives, not wife, for he has many.

The Sea-elephants go to wild, lonely islands, and there make their nurseries. Year after year tens of thousands of the big Seals gather, to fight and to rear their young. The clumsy great father Sea-elephants fight terrible battles; and at this time always seem to be in a very bad temper, tearing each other with their tusk-like teeth. Their roaring can be heard far out at sea; but the lady Seals take no part in these combats.

We have no room in this lesson to look at all the other kinds of Seals, Sea-lions, Sea-bears and Walrus. As we have already noticed, the sealskin sold in shops is really the skin of a Sea-lion. Sometimes these are called Eared Seals, for they possess little ears, while the real Seals have only small holes in the side of the head for ears. Again, there are some Eared Seals whose fur is of no use to us, for it lacks the deep under-fur of the fur Seals.

Nature gave this coat to the Seal to protect him from the cold, but it has