This nest is always made by the male fish, and when it is quite finished his mate comes and lays her eggs in it. Then for eight or nine days he remains on guard outside the entrance, so as to prevent any hungry creature from finding its way in and devouring them. At the end of that time the eggs hatch, and a number of baby gobies make their appearance; and although they are so small that one can hardly see them, the father-fish seems to think that they are quite able to take care of themselves. So he swims away, and leaves them to their fate. If you catch these little fishes with your fingers you must be careful how you handle them, for they have rather long and sharp teeth, and can give quite a smart bite. PLATE II THE SMOOTH BLENNY (1) This fish, which is sometimes known as the Shanny, is also very common in the rock-pools. But you are not likely to see it unless you bale out all the water from a pool, for it always hides during the daytime in the crannies among the rocks, or underneath sea-weeds. Or it will even burrow down into the sandy mud beneath a big stone, so that you will not find it at all unless you dig for it. When it is fully grown this fish is about five inches long, and it is quite a remarkable creature in several different ways. In the first place, it varies a great deal in colour. Sometimes it is partly green and partly yellow, sometimes it is olive brown nearly all over, and sometimes it is almost black. But you can always tell it by the ring of bright crimson which surrounds each eye. In the second place, it can remain for quite a long time out of the water. Some fishes die almost at once if they are taken out of the sea. But a blenny can live on dry land for twenty-four hours at least. The reason is that its gills are made in such a way that they remain damp for a long while after the fish leaves the water; and as long as the gills are moist it is able to breathe. [Illustration: PLATE II 1. THE SMOOTH BLENNY. 2. THE SPOTTED GUNNELL.] So very often indeed a smooth blenny will hide in a crevice which is left quite dry when the tide begins to fall, and will stay there till it rises again, perhaps eight or ten hours later. But the oddest thing about this little fish is that it can move one of its eyes about without moving the other! Have you ever seen a chameleon? If so, you must have noticed how it will turn one of its curious eyes, first in one direction, and then in another, while the other eye remains quite still. And the blenny can move its eyes in just the same way, so that very often when one of them is looking out in front the other will be looking out behind. And then one will twist round and look upwards, while the other twists round and looks down! If you succeed in catching a smooth blenny, you can always tell it from the other fishes which live in the rock-pools by the deep notch in the middle of the fin which runs along its back. PLATE II THE SPOTTED GUNNELL (2)