"Yes, it's the largest of the flatfish. There's a record of one halibut having been caught weighing a trifle over five hundred pounds. Usually a fish one-fifth of that size is considered large."

"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."

"Yet," said the other, smiling, "the birds don't have it all their own way. Sometimes the fish gobble them!"

"Can they eat birds?"

"It's a little rare," was the reply, "but there's one authentic case on record in which a fish's stomach was found to contain no less than seven wild ducks."

"Why, I always thought that fish had a small mouth in proportion to their size. It must have been a monstrous big one!"

"It was not much more than four feet long," was the reply; "but it is one of the few fishes having a huge mouth. They sometimes call it a goosefish, because it attacks wild geese, but the right name is fishing-frog or angler. It glides along the bottom until directly beneath where ducks are feeding, and when one dives for worms in the mud--you know the way ducks go down--the angler catches it by the neck and drags it down and then swallows it at leisure. You see the bird hasn't a chance, because all the angler-fish has to do is to hold it until it strangles."

This led to a discussion of the food of fishes, and under the spur of the boy's questions, the scientist outlined for him the dietary of almost every fish that swims, together with all the various ways in which water is aerated, such as the growth of water-plants and the currents of streams.

"It still seems to me," said Colin, "that nearly every fish lives by fighting some other fish. It's a wonder," he added, with a laugh, "that there aren't some professional fighters among them."

"There are," his friend replied; "that is to say, in the sense you mean.

There's a fish which is called the fighting-fish, that is regularly trained by the fishermen, and the combats are so famous that when one is scheduled to come off a big crowd gathers."

"Where?" asked Colin incredulously. "That sounds a little as if you thought I was one of the marines, Dr. Jimson."

"It is absolutely the case," was the reply. "And, what is more, they advertise these fights widely and get big gate receipts, just like a baseball game here. The sum of money taken in for admissions, too, has become so large that the Crown refuses to allow the fights to be held unless a certain percentage is paid over to the king."

"Where can that be?"

"In Siam," was the reply. "The fighting-fish is distantly related to the perch, but it has been used for public combats for so long that it has become highly specialized. It is really a sort of gamec.o.c.k among fish, and the money expended in licenses in Siam brings in a comfortable revenue to the Crown. The owner of a champion fighting-fish never needs to work for a living, he can easily be supported by the winnings of his possession. Often a fish or a team of fishes is owned by a village and the rivalry between communities is intense. The Siamese are inveterate gamblers, also, and in more than one instance the Siamese Government has had to send supplies to a village which was threatened with famine because all the villagers had lost their crops through betting upon the success of their team of fighting-fish."

"You say it's a kind of perch?"

"Only distantly," was the reply; "it belongs to a very curious group of fishes which cannot live long in the water unless they can breathe air once in a while, nor can they live very long in air, unless they breathe water occasionally. The fish that climbs tall trees is a member of the same sub-order."

"You mean the skippy?"

"No," the scientist answered; "it's a much better climber than the skippy. It will run up the trunk of a palm tree."

"Now come, Dr. Jimson," expostulated Colin. "Do you expect me to believe that?"

"Certainly, when it is true," came the reply. "The statement often has been made and then disbelieved, but there is plenty of scientific evidence now to arm its truth."

"Does it climb up to the top and crack cocoa-nuts?" queried the boy, still incredulously.

"Not quite that," his friend said, smiling. "I believe seven feet is as high a climb as is known, that being recorded officially by one of the staff of the Madras Government Central Museum. The creature usually only climbs during a heavy tropical rainstorm, and it is believed that the fish, accustomed to ascending tiny streams, is stimulated to climb the tree by the rush of water flowing down the bark. The gill cover is movable, and the spines of the ventral fins very sharp. It doesn't go up head first, you know, but sideways."

"How does the fish climb down, then?" queried Colin.

"Tumbles," was the laconic reply.

"And starts up again?"

"No, it usually hops sideways over land to a mud-bank again, not to have another climbing fit until the next big tropical shower comes after a period of drought. But if you wanted to find out all the strange habits of fishes," continued his friend, as the schooner ran into New Bedford harbor, "it would take more time than one swordfish trip would give you."

[Ill.u.s.tration: CLAMMER RAKING FOR QUAHAUGS IN NEW BEDFORD HARBOR.

_Courtesy of the U. S. Bureau of Fisheries._]

[Ill.u.s.tration: OYSTERMAN TONGING FOR OYSTERS IN BUZZARD'S BAY.

_Courtesy of the U. S. Bureau of Fisheries._]

On the way back to Woods Hole, going down the harbor, Colin questioned the captain of the M. B. L. boat, the _Cayadetta_,--which happened to have been at New Bedford that afternoon, and on which he had been given the courtesy of a pa.s.sage--why there seemed to be two different kinds of boats scattered over the harbor oystering.

"That feller's not oysterin'," the captain answered; "he's rakin'

quahogs."

"Quahogs?"

"That's clams," was the explanation; "the right name for what the people down in New York call a 'little-neck clam.' The 'neck' is a foot, and it's little because the quahog doesn't burrow deep. The long or soft clam does."

"And he just pulls them up with a rake?"

"Yep," was the reply; "big rake with curved tines to it. You see he jerks his rake along until he feels it full, then pulls it up. Now, this feller, over on the other side here, he's not goin' after clams at all.

He's oysterin'. Ef you'll notice, he has two poles an' he works 'em apart an' together again like a pair o' shears, an' then when he feels he has a load, he hauls it up the same way, picks out the oysters that are big enough, an' throws the small ones back together with the stones an' other rubbish that he has brought up. They call that 'tonging'

oysters, an' the thing he uses is called the 'tongs.'"

"I've been wondering," said Colin, as they pa.s.sed over the bay and he noted again all the lobster-pot buoys which had interested him so greatly on the way to New Bedford, "I've been wondering whether there was any crabbing done up this way?"

"Not much," the captain answered; "there's one caught now an' again, but all the good eatin' crabs belong further south. New Jersey's the place f'r crabs, an' I reckon most o' the soft-sh.e.l.l crabs o' the country come from there, but the business o' cannin' crabs is done way down in Chesapeake Bay, where there's crabs no end."

"A soft-sh.e.l.l crab is just the same species as the regular blue crab, isn't it," asked the boy; "only it has cast its sh.e.l.l?"