“I know,” said the fisherman, “that horse-hairs in ponds will turn into long worms. But I never did think these shells would turn into birds.”
“And horse-hairs will never turn into worms. Long, thin, black worms in ponds look much like the hairs of a horse’s tail, so some people think they must once have been horse-tail hairs. But it is not so. Horse-hairs are always only horse-hairs, and worms all come from eggs which were laid to bring out a worm.”
“It is a pity,” said the fisherman, “that when I was a boy in school my books did not tell me of these things. It would have been nice to know what I was looking at as I went about the world.”
Now let us study these barnacles of which our fisherman spoke. He told us truly about their number and where they grow. He told us what he knew because it was what he had seen.
There are two kinds of barnacles,—those that have stems, and those that have no stems. The kind that has no stems is the kind you will see oftener, though there are plenty of the other kind.
The stemless, or acorn barnacles, are placed flat upon whatever they grow on. Try to pull one off a stone. You cannot do it while the animal is alive. When the animal is dead or dying, you can move the shell from what it grows upon. After the animal has been dead some time, the shells drop from their places, and leave room for others to grow.
All barnacles do not fix themselves upon dead bodies, such as stones, wood, or shells. Many of them fasten upon living animals, and are carried about with them from place to place. Perhaps they enjoy travel!
In the North Sea many sharks have barnacles growing upon them. The stem of the barnacle has little hollow hairs, and these enter into the flesh of the shark and hold fast there. Others have been found keeping house upon the whale’s skin, and yet others on the shells of turtles.
These barnacles which you find by the shore are small things, you can hold several of them in your hand at once. Far down in the ocean lives a huge giant barnacle, so big that some of you could hardly lift him.