It is quite a common thing to find a shore crab with one or more legs wanting, or with one large pincer and one small one. What is the reason of this? It means that at one time or other the crab has had a limb torn off in a fight, for the males are continually fighting with one another. When a limb is lost it is not a very serious matter, for a new limb soon begins to grow on again, and after a time becomes as large as the lost one. There are times, however, when the crab is by no means pugnacious. One sometimes finds under a stone a crab which has hardly enough spirit to lift his pincers in self-defence. On touching him one finds that he is quite soft. What has happened to him? He has recently been casting his coat; for, as the animal goes on growing within his shell, he becomes too big for it, and the only thing he can do is to burst the shell and come out of it, and then wait for a bigger one to grow. When he is thus moulting, he is glad to crawl away and hide till he is able to face the world again. Many of the empty crab shells that one picks up on the beach are the old cast-off clothes of crabs still alive and vigorous. By examining one of these we can see how thorough the process of moulting is; not only are the shells of his back and his legs thrown off, but the covering of his eyes, his feelers, his mouth parts, and even the inside lining of his stomach,—for, strange to say, the wall of his stomach is lined with the same kind of shell as the outside of his body. The crab is formed for living in water, but he can stand long exposure to the air. If you cover him with damp garden soil or peat mould he will survive for days. The reason is that so long as his gills are kept damp he can breathe and live quite well. The lobster breathes in exactly the same way, and when lobsters are being shipped for the southern markets they are put in boxes with layers of wet seaweed to keep them alive. Have you ever seen the beautiful set of gills which the crab has? If you find a dead crab that has been lying on the beach for some little time, you can easily remove the upper shell, leaving the soft parts of the body with the legs attached. Just above the attachment of the legs there is a series of brown feathery-looking things which seem to cover the whole side of the body. These are the gills. They lie in a special chamber, occupying about half of the whole space inside the shell. While the crab is alive, the gills are continually bathed in a current of water, which is pumped in through a small hole at the side of his mouth and drawn out at another hole near it. If the gills become dry the animal soon dies. There is a curious pointed flap folded tightly across the crab’s body underneath, which is commonly called its “purse.” It used to be a schoolboy belief that the crab carries its money here. The fact simply is that the purse is kept closed for the sake of protection, as the skin underneath it is soft and might easily be injured in a fight.