There is just one more thing that I must tell you about these very curious creatures, and that is that they are very fond of covering themselves all over with small stones, and little bits of broken shell, and tiny pieces of sea-weed, in order that they may not be noticed. They do this in a very odd way. I told you that they have numbers of little sucker-feet, which they poke out through tiny holes in their shells when they are required for use, just as the starfishes do. Well, when they want to disguise themselves, they just push out two or three hundred of these slender sucker-feet between their spines, and take firm hold with them of any small objects that may be lying within reach. In this manner they soon succeed in covering themselves all over, and you might easily look at one of them as it lay at the bottom of a rock-pool without recognising it at all.