"Flatfish are funny creatures," said Colin. "I've often wondered how the eyes in various species wander around in their heads."
"Other people have wondered, too," said his companion.
"Well, but we know something about it, don't we?" protested the lad. "Aren't the eyes all right in the young fish?"
"Certainly," was the reply, "and, what's more, the young fish swims upright."
"How does the eye move round, then? Does the eye on one side go blind and another one grow on?"
"No," answered his friend; "your first idea was the right one, the eye moves round. But, as a matter of fact, it goes through the body. The young flatfish is thin and almost transparent, and when it begins to be time for the eye to change
from one side of the body to the other it sinks in. A thin, transparent skin grows over the socket and the eye sinks in and in, the bones moving away from before it, until it has come near the proper place on the other side. Then a new socket opens for the eye, and it finally arrives at the end of its journey through the head, thus coming on the same side as the other eye. At the same time, too, the flatfish gets the habit of swimming on its side, and its color scheme changes, one side—which has become the bottom—being white, while the upper side is dark and spotted to look like the stones on the bottom of the sea."
"What do flatfish eat?"
"Everything," was the reply, "from a clam to a codfish. But the favorite food of the halibut, for instance, is sting-ray, and consequently it is a good friend of the oysterman; where there is plenty of halibut, there will be few sting-rays, and these last are destructive to a good oyster-bed."
"It seems to me," said Colin, "that the whole story of the seas is that fish eat fish, while the few that escape from their own kind are gobbled up by seagulls and terns and other birds."