In its habits the plaice is very much like the flounder, except that it does not like lying upon mud, and always chooses a spot where the bottom of the sea is sandy. And the skin of the upper side of its body, instead of growing dark brown, like the colour of mud, becomes speckled and spotted like the surface of sand. The fish is always very careful indeed to conceal itself, for even when the sea-bottom is sandy it does not lie upon the surface, but wriggles its way right down into the sand, only leaving just its eyes and a small part of its head above it. You can always tell a plaice when you see it by the bright reddish-yellow spots upon the upper side of its body and its fins. And besides these, it always has a row of little bony knobs on the upper side of its head. You can catch it just as you can catch flounders, by paddling in the sea. But the plaice which are caught in this way are always quite small ones, for the bigger fish, which sometimes weigh as much as twelve or even fifteen pounds, live in the deeper water at some little distance from the shore. PLATE VI THE EGG OF THE SKATE (1) Very often indeed, as you walk along the sea-shore, you will find a curious object which the fishermen generally call a “mermaid’s purse.” It is about three inches long and two inches wide, and is made of a black, horny substance, so tough and hard that it is very difficult indeed to tear it. And from each corner there projects a slender tube, about an inch in length. In fact it looks rather like a hand-barrow, with handles in front as well as at the back, instead of wheels. [Illustration: PLATE V THE PLAICE.] This is an egg of that very curious fish which we call the Skate, and which looks something like one of the “flat” fishes with a long whip-like tail. So it is sometimes called a “skate-barrow.” When it is flung up on the beach by the waves the egg is nearly always empty. But if you happen to be staying by the sea-side in the early spring, and go down for a walk along the beach after a violent storm, you may perhaps find one of these eggs with a baby skate inside it. And if you examine the egg very carefully, you will find that while one end is firmly closed up, the other end has a slit running right across it, and that this slit is made in such a way that it allows the little fish to pass out quite easily when the proper time comes, but quite prevents any other creature from coming in. PLATE VI THE EGG OF THE DOG-FISH (2) On some parts of the coast you may often find an empty egg which is very much like that of the skate, for it is made of just the same horny material, and is of just the same shape. But at the four corners, instead of having straight projections like the handles of a barrow, it has long, twisted tendrils, just like those of a vine.