The Garden Snail

Teacher's Story

ERCHANCE if those who speak so glibly of a "snail's pace" should study it, they would not sneer at it, for carefully observed, it seems the most wonderful method of locomotion ever devised by animal. Naturally enough, the snail cannot gallop since it has but one foot; but it is safe to assert that this foot, which is the entire lower side of the body, is a remarkable organ of locomotion. Let a snail crawl up the side of a tumbler and note how this foot stretches out and holds on. It has flanges along the sides, which secrete an adhesive substance that enables the snail to cling, and yet it also has the power of letting go at will. The slow, even, pushing forward of the whole body, weighted by the unbalanced shell, is as mysterious and seemingly as inevitable, as the march of fate, so little is the motion connected with any apparent muscular effort. But when his snailship wishes to let go and retire from the world, this foot performs a feat which is certainly worthy of a juggler; it folds itself lengthwise, and the end on which the head is retires first into the shell, the tail end of the foot being the last to disappear. And now find your snail!

Never was an animal so capable of stretching out and then folding up all its organs, as is this little tramp who carries his house with him. Turn one on his back when he has withdrawn into his little hermitage, and watch what happens. Soon he concludes he will find out where he is, and why he is bottomside up; as the first evidence of this, the hind end of the foot, which was folded together, pushes forth; then the head and horns come bubbling out. The horns are not horns at all, but each is a stalk bearing an eye on the tip. This is arranged conveniently, like a marble fastened to the tip of a glove finger. When a snail wishes to see, it stretches forth the stalk as if it were made of rubber; but if danger is perceived, the eye is pulled back exactly as if the marble were pulled back through the middle of the glove finger; or as a boy would say, "it goes into the hole and pulls the hole in after it." Just below the stalked eyes, is another pair of shorter horns, which are feelers, and which may be drawn back in the same manner; they are used constantly for testing the nature of the surface on which the snail is crawling. It is an interesting experiment to see how near to the eyes and the feelers we can place an object, before driving them back in. With these two pairs of sense organs pushed out in front of him, the snail is well equipped to observe the topography of his immediate vicinity; if he wishes to explore above, he can stand on the tip of his tail and reach far up; and if there is anything to take hold of, he can glue his toe fast to it and pull himself up. Moreover, I am convinced that snails have decided views about where they wish to go, for I have tried by the hour to keep them marching lengthwise on the piazza railing, so as to study them; and every snail was determined to go crosswise and crawl under the edge, where it was nice and dark.

It is interesting to observe through a lens, the way a snail takes his dinner; place before him a piece of sweet apple or other soft fruit, and he will lift himself on his front toe and begin to work his way into the fruit. He has an efficient set of upper teeth, which look like a saw and are colored as if he chewed tobacco; with these teeth and with his round tongue, which we can see popping out, he soon makes an appreciable hole in the pulp; but his table manners are not nice, since he is a hopeless slobberer.

There are right and left spiraled snails. All those observed for this lesson show the spiral wound about the center from left over to right, or in the direction of the movement of the hands of a clock, and this is usually the case. With the spiral like this, the breathing pore is on the right side of the snail and may be seen as an opening where the snail joins the shell. This pore may be seen to open and contract slowly; by this motion, the air is sucked into the shell where it bathes the snail's lung, and is then forced out—a process very similar to our own breathing.

1. The thorny path to bliss; 2. Snail showing the breathing-pore; 3. Prospecting.

The snail has good judgment when attacked; at the first scare, he simply draws in his eyes and feelers and withdraws his head, so that nothing can be seen of him from above, except a hard shell which would not attract the passing bird. But if the attack continues, he lets go all hold on the world, and nothing can be seen of him but a little mass which blocks the door to his house; and if he is obliged to experience a drought, he makes a pane of glass out of mucus across his door, and thus stops evaporation. This is a very wise precaution, because the snail is made up largely of moisture and much water is needed to keep his mucilage factory running.

The way the snail uses his eyes is comical; he goes to the edge of a leaf and pokes one eye over to see what the new territory is like; but if his eye strikes an object, he pulls that one back, and prospects for a time with the other. He can lengthen the eye-stalk amazingly if he has need. How convenient for us if we could thus see around a corner. If a small boy were as well off as a snail, he could see the entire ball game through a knot-hole in the fence. In fact, the more we study the snail, the more we admire, first his powers of ascertaining what there is in the world, and then his power of getting around in the world by climbing recklessly and relentlessly over obstacles, not caring whether he is right side up on the floor or hanging wrong side up from the ceiling; and, finally, we admire his utter reticence when things do not go to suit him. I think the reason I always call a snail "he" is because he seems such a philosopher—a Diogenes in his tub. However, since the snail combines both sexes in one individual the pronoun is surely applicable.

When observed through a lens, the snail's skin looks like that of the alligator, rough and divided into plates, with a surface like pebbled leather; and no insect intruder can crawl up his foot and get into the shell "unbeknownst," for the shell is grown fast to the flange, that grows out of the middle of the snail's back. The smoother the surface the snail is crawling upon, the harder to make him let go. The reason for this lies in the mucus, which he secretes as he goes, and which enables him to fasten himself anywhere; he can crawl up walls or beneath any horizontal surface, shell downward, and he leaves a shining trail behind him wherever he goes.

Snail eggs are as large as small peas, almost transparent, covered with very soft shells, and fastened together by mucus. They are laid under stones and decaying leaves. As soon as the baby snail hatches, it has a shell with only one spiral turn in it; as it grows, it adds layer after layer to the shell on the rim about the opening—which is called the lip; these layers we can see as ridges on the shell. If we open an empty shell, we can see the progress of growth in the size of the spirals. Snails eat succulent leaves and other soft vegetable matter. During the winter, they bury themselves beneath objects or retire into soft humus. In preparing for the winter, the snail makes a door of mucus and lime, or sometimes three doors, one behind another, across the entrance to his shell, leaving a tiny hole to admit the air. There are varieties of snails which are eaten as dainties in Europe, and are grown on snail farms for the markets. The species most commonly used is the same as that which was regarded as a table luxury by the ancient Romans.

References—Wild Life, Ingersoll; The Natural History of Some Common Animals, Latter.

Method—The pupils should make a snailery, which may consist of any glass jar, with a little soil and some moss or leaves at the bottom, and a shallow dish of water at one side. The moss and soil should be kept moist. Place the snails in this and give them fresh leaves or pulpy fruit, and they will live comfortably in confinement. A bit of cheese-cloth fastened with a rubber band should be placed over the top of the jar. A tumbler inverted over a dish, on which is a leaf or two, makes a good observation cage to pass around the room for closer examination. An empty shell should be at hand, which may be opened and examined.

3. What sort of a track does a snail leave behind it? What is the use of this mucus?

4. Where are the snail's eyes? Why is this arrangement convenient? If we touch one of the eyes what happens? What advantage is this to the snail? Can it pull in one eye and leave the other out?

5. Look below the eyes for a pair of feelers. What happens to these if you touch them?

6. What is the use of its shell to a snail? What does the snail do if startled? If attacked? When a snail is withdrawn into its shell can you see any part of the body? Is the shell attached to the middle of the foot? How did the shell grow on the snail's back? How many spiral turns are there in the full-grown shell? Are there as many in the shell of a young snail? Can you see the little ridges on the shell? Do you think that these show the way the shell grew?

7. Can you find the opening through which the snail draws its breath? Where is this opening? Describe its action.

8. Put the snail in a dry place for two or three days, and see what happens. Do you think this is for the purpose of keeping in moisture? What does the snail do during the winter?

9. Place a snail on its back and see how it rights itself. Describe the way it eats. Can you see the horny upper jaw? Can you see the rasping tongue? What do snails live on?

10. Do you know how the snail eggs look and where they are laid? How large is the shell of the smallest garden snail you ever saw? How many spiral turns were there in it? Open an empty snail shell and see how the spirals widened as the snail grew. Do you think the shell grew by layers added to the lip?

11. Do all snails have shells? Describe all the kinds of snails you know. What people consider snails a table delicacy?