How to Know Shells
Oysters are preeminent among edible mollusks, with clams and cockles, and snails and scallops in a long train after them. An oyster is preeminent, too, as the source of the world's wealth 4 How to Know Shells in pearls. Mother-of-pearl is the lining of shells. Pearl buttons are cut from shells of the fresh-water clams. Cameos are cut from conchs and helmet shells. Sepia ink and the far-famed Tyrian dyes are molluscan secretions. Royal robes were woven of the threads by which the little pen shell clings to its rocky abode. A little cowrie of handy size and shape is the. "money shell" of African tribes, the currency used in all traffic. But these interesting mollusks we can only read about. There are others closer by.
Go with me down to the seashore when the tide is out. It takes time to get the eyes and the mind focused upon what one is looking at. The beach is scattered with the dead shells of its own inhabitants. Between the limits of the high and low tides is a zone of life that follows in and out the curves and angles of the crumbling sea wall. In the tide pools, under the smooth sand, on rocks, under spreading green seaweed, live the creatures of the seashore. They are retiring in disposition. Very naturally they do not wave us a welcome.
How quickly a child throws away a lapful of wave-worn shells to watch the doings of a live one! Do you see that small jet of water spouting upward? The spade thrust deftly under turns out a slim razor clam. Watch or he will dive into the sand before you can get him into the pail of sea water. Fill it half full of sand and how quickly he is out of sight.
What is that ridge on the smooth sand? The boy explores it with his bare toe, and turns out a surprised moon shell. Watch the disturbed creature draw his great foot into the stout shell, and shut the world out with the horny door.
Those familiar "sand collars," so fragile when they are dry, turn out to be the egg-carrier of the moon shell. And the poor clams whose shells are bored with neat round holes near the beaks are victims of the moon shell's voracious appetite. It is easy to prove this by putting the two together alive in the pail and leaving them over night. Sometimes a shell scampers clumsily over the sand instead of sedately plodding along just under the surface. It tumbles over, and reveals a sheaf of jointed arms at the opening. The original owner has been superseded by that inveterate house hunter, the hermit crab.
There is positively no end to the new discoveries one makes when the eyes are once open to the strange doings of the shore 5 How to Know Shells dwellers. It is not study to watch them. It is one of the finest
ways to put in the vacation of a brain-worker. It is true recrea tion. If the sojourn lasts a week or longer, have a jar of sea water with sandy bottom and some green seaweed to keep it. pure. Put the creatures you wish to watch into this aquarium—a miniature ocean—for your convenience and pleasure. Here the shy mollusks will lose their self-consciousness, and live their lives as contentedly and naturally as the bolder ones.
If you live inland you may never achieve a vacation at the seashore. Go to the lake or the stream nearest home. Sweep the edges of the ditch with a dip net. Rake the bottom of the brook and the pond. The number of aquatic mollusks living in such situations is such that you soon abandon the idea that all but a few live in the sea. No marine specimen ever exhibits more intelligence or agility than the little bladder snail that lives on plants in ponds and ditches. Put a few in an aquarium jar in spring. The eggs, then the young, will hold your interest like a play. Through their eventful youth these little gymnasts will migrate in straight lines, at various angles, from one part of the tank to another, on threads of mucus, fine as a spider's web. Their tricks are amazing and amusing, in infinite variety.
The inlander has at hand all the air-breathing mollusks, the land snails of his region. The forest snails hide under loose bark, and under decaying logs. Sun-enduring kinds hide among grass roots, and among more luxuriant vegetation, and fare forth in damp weather or only by night. The number of the land snails is very great, even in our temperate zone.
Little is yet known about the life history of many of these. The limits of distribution are vague and inaccurate for many. When does this snail lay its eggs? How long do the young require to reach maturity ? When does that species seal up its doorway and go into the ground to spend the winter? The young con chologist can ascertain the correct name of a specimen by sending it to one of the scientific institutions named on page 8, where a specialist will answer his inquiry. The careful observer, if he keeps a note-book, may discover and pass on to conchologists valuable facts in the life history of little-known species. The study of our land mollusks is very incomplete. It is a worthy and enjoyable opportunity that is open to earnest young natural ists to-day.