Sea Urchins
You have, perhaps, found some of their beautiful shells on the beach, empty of all life and bleached quite white by
Shell of Sea Urchin. the sun. Where the green spines grew are regular rows of bead-like projections, looking like strings of pearls; but, lovely and pure as the shells are, they cannot possibly be as interesting as the real creatures, full of life, crawling about at the bottom of the crystal pool on
Sea Urchin. the tips of their prickly looking spines.
I have never found a live sea-urchin except in these quiet pools, probably because they do not like to subject themselves to the buffeting waves, and when in deep water hide in the crevices of the rocks or bury themselves in the seaweed.
Unlike the sea-anemone, they are vegetarians and seldom indulge in animal food. The mouth is underneath the little animal, where you find the round hole in the shell.
Starfish
too you will probably see crawling over the rocks at the bottom of the pool. Although called by that name, these strange, five-fingered creatures are no more fish than the sea-urchins, and their life is not so much of the water as of the ground below. The starfish may swim, but it greatly prefers gliding about over the slippery stones and sandy bottom, searching for the small shellfish which form its food. If you will place a starfish in a small fish globe filled with salt water, or in any clear glass vessel that is large enough, you can see its numberless feet, which are little tubes projecting from the under side of the five rays. This wonderful waving mass of tube feet is quite concealed when we look at the animal from above, and until we have discovered them its rapid movements seem very marvellous.