Tops are generally very common indeed on the sandy parts of the shore. You cannot possibly mistake their shells for those of any other creatures, for they are cone-shaped, looking very much like rather flattened sugar-loaves, and are generally very beautifully coloured. So pretty are they, indeed, that they are sometimes strung together and worn as necklaces, or used for ornamenting ladies’ dresses.
The painted top is one of the most beautiful of all these shells, for it is covered all over with spots and streaks and blotches of scarlet, and crimson, and pink, and purple, and white, and blue, and yellow! But all this lovely colouring is only on the outer coat of the shell, which is very easily chipped off. The consequence is that these shells are very often damaged by being tossed to and fro by the waves, and though you may often find twenty or thirty in the course of a morning, not more than two or three, perhaps, will be quite uninjured.
Tops are very useful creatures to have alive in an aquarium, for they keep the glass sides clean from the tiny green weeds which so quickly grow upon them. They do this by means of their tooth-ribbons, and you may see them crawling about on the glass walls and mowing down the weeds, just as a gardener cuts the grass on the lawn with his scythe.
The painted top is rather a large shell, for it is often nearly an inch in height from the peak to the margin. But the Grey Top, which is even commoner still, is a good deal smaller. It is not nearly so brightly tinted as the painted top, for it is yellowish grey in colour, with zigzag black streaks running round and round it, which give it rather a mottled look. Still, it is a very pretty shell indeed.
If you look at a top shell from underneath, you will always find that there is a small hole in the bottom. This is the entrance to a passage which runs right up into the peak of the shell. In the grey top this hole is just about big enough to admit a rather fine needle.
No doubt you have often found this very pretty shell, for on the sandy parts of our coasts it is sometimes very common. You may often find twenty or thirty cowries, indeed, in one of those ridges of pebbles and small coal which are washed up by every tide. But if you were to see the living animals crawling about I do not think that you would ever guess what they were, for their soft bodies come outside their shells, which they cover up so completely that you can hardly see them at all.
If you look on the upper part of the shell, you will see that a pale streak runs across it from one side to the other. This streak marks the line where the edges of the two sides of the body almost meet.
In some parts of the world cowry shells are used instead of money. It seems rather an easy way of getting rich, doesn’t it, just to go and pick up shells on the sea-shore? But then fifteen hundred of these cowries are only worth about a shilling, so that you would have to pick up a very great many even if you only wanted to do a day’s shopping! And then they are ever so much bigger than our English cowries, so that it would not be very easy to carry them about. You would have to take several sacks full of cowries with you when you went to make a purchase, instead of just keeping your money in a purse!
The chiton is one of the oddest of all the shell-bearing molluscs; for it does not look like a mollusc at all. It looks much more like a kind of sea woodlouse, or a very tiny armadillo. For instead of having a single shell like a whelk or a periwinkle, or a double one like a cockle or an oyster, it has eight shelly plates on its back which overlap one another, just like the tiles on the roof of a house. And if you touch it, it will often roll itself up into a kind of ball, just like the pill-millepedes, or “monkey-peas,” which are so common in our gardens.