Here we are on an island of the Southern Seas--the home of a colony of cocoanut crabs. One of the members of the colony is climbing a tree to get a nut. "And who has a better right?" says he. "This tree," he might continue, "is the descendant of a nut that some of my ancestors sailed upon to this island; for a cocoanut, dropping into the water from a tree near some far shore, often carries on it the crab who had started to eat it. Then a current of the sea carries the nut and its passenger to some other island. Later cocoanut Santa Marias and their Columbuses reach the island in the same way, and so it becomes populated with both cocoanuts and crabs--which makes it very nice for the crabs!"] One of the big families of crabs live on land most of the time and make burrows in which they live. These have legs specially fitted for digging. Like most of the crab family, the land-crab earns its living at night and, except in rainy weather, seldom leaves its burrow by day. Like small boys, these crabs seem to love to play in the rain. The fact is they do this to keep their gills wet; for, although they spend most of their time on land, crabs breathe with their gills, like fish; and while some of them--as the mountain crab of the West Indies--live quite a distance back from the sea, they must have some moisture for their gills, and this they get, in part, in their damp cellars--the burrows. But it's queer, isn't it, what different ways people have of looking at things? Take land crabs and turtles, for example. Turtles, when they lay their eggs, think the only thing is to get clear away from the water and put their eggs in an incubator, as we saw them do a few pages back. The land-crabs evidently think just the opposite; for no matter how far they may live away from the sea--one, two, even three miles sometimes--nothing will do but they must go to the water to lay their eggs. In April and May you'll see them swarming down by hundreds and thousands. And they'll climb right over you if you don't get out of their way! "This is my busy day and I can't stop for anything," says Mrs. Crab. Besides the work they do for the soil in grinding and mixing it, the crab people, like all the crustaceans, help a lot by adding lime to it, and that's one of the very best things you can do to soil, you know. They add this lime when they change their clothes; that is, when they moult or cast their shells. The shell they take off as if it were indeed a dress. They "unbutton" it down the back. Sometimes, in trying to get out of the legs of the suit, they leave not only the leg covering but the leg itself. That leg is good for the soil, too, of course, and the loss of a leg doesn't bother a crab so very much. He just grows a new one, that's all!