In this little book I want to talk to you about some of the strange and wonderful creatures which you may find when you go to stay by the sea-side. And first of all I should like to tell you something about the fishes. A great many of these, of course, live in the deep water, where you cannot catch them, or even see them. But there are a good many others which you can find very easily indeed. All that you have to do is to wait until the tide has gone out, and then to go down and look into the pools which are left among the rocks. There you are almost sure to see a number of shadowy forms darting to and fro through the water. Some of these, most likely, will be shrimps and prawns, which are always very common in the rock-pools; but the others will be tiny fishes. And even if you have not got a net you can often catch them quite easily. Just bale out the water with a small pail, or even with your hands, until the pool is nearly empty, and you will be able to seize them with your fingers. Among the fishes which can be caught in this manner are several kinds of Gobies. You can easily tell them from all other fishes by the curious way in which their lower fins are made. These fins are placed close together, so as to form a kind of cup-shaped sucker or soft pad, by means of which the little creatures can cling so firmly to the rocks that even a wave will not wash them from their hold. And if you take them home alive and put them into a basin full of sea-water, they will cling to the sides and stare at you in a most inquisitive way! Owing to this habit the gobies are often called “rock-fishes.” The commonest of these odd little creatures, perhaps, is the Black Goby. But the Spotted Goby is very nearly as plentiful. It is rather hard to see, because it is coloured just like the sand at the bottom of the pool, on which it is very fond of resting. But if you scoop out the water from a shallow pool you will often find, not only the goby, but its nest as well. For this little fish makes a most curious nest in which to place its eggs. First of all it hunts about till it has found half an empty cockle-shell, lying at the bottom of the water with its hollow side downwards. It then scoops out the sand from underneath it, so as to form a little chamber about as big as a marble. You would think that the walls of this chamber would very soon fall in, wouldn’t you? But the fish smears them all over with a kind of slime, which very soon sets and becomes quite hard, just like cement. It then makes a tunnel leading into the chamber by means of which it can go in and out; and last of all it covers the cockle-shell all over with loose sand. So unless you look very carefully at the bottom of the pool you will not see the nest at all. But if you notice a kind of lump in the sand, and find that half a cockle-shell is buried underneath it, you may be pretty well sure that you have discovered the home of a spotted goby.