faced seaman waved a hand toward the upper end of the
island.

"They went off that way, sir. Ain't showed up yet."

"Well, let's row up and meet 'em," suggested Mart. Bob agreed at once,
and all three piled into the boat as they shoved it out.

Mart and Dailey took an oar apiece, Bob reclining in the stern, and they
slowly rowed up toward the far end of the island, where was a wide
channel connecting the lagoon with the open sea beyond.

As they rowed, the two boys were lost in wonder at sight of the glories
below them, for here the water was clear as crystal, though Dailey
declared it to be a couple of fathoms deep or more. Sponges, marine
fans, fish, coral, and all the under-water life lay open to them, in
colors more gorgeous and magnificent than either boy had ever dreamed
of. Bob declared it far ahead of the Santa Catalina sea-gardens, and
Mart could hardly row for his wondering admiration; but he was finally
recalled to himself by a quick exclamation from Bob.

"Hold up there, both o' you! What's that ahead?"

Mart and Dailey glanced around, and an echoing cry broke from the
seaman. Fifty yards ahead of them and slowly cutting the water in their
direction, was a black triangle that seemed part of some machine, so
evenly and steadily did it move along. But the size of it! Mart guessed
instantly that it was the dorsal fin of a shark, but he had seen no fin
of such size before.

"It's the Pirate Shark, Holly!" he cried suddenly, and plunged down for
the rifle. Bob stooped for it at the same instant, but Mart was too
quick for him. He rose again to find Dailey looking at them, aghast.

"Where might you lads 'a' heard o' the Pirate Shark?" queried the seaman
hoarsely. Mart had no time to waste on him.

"None of your business," he returned sharply. "Keep steady there--"

"You'll waste the bullet, Mart," and Bob stopped him. "It'll simply
glance off the water at this angle. Hold on till we get closer!"

"Don't you do it, sir," implored Dailey, his leathery face suddenly
pale. "It's the Pirate Shark, all right--don't you fire on him, sir! My
word on it, Mr. Judson, it'll be a bad day for us all--"

"Oh, cut out that superstitious talk, Dailey," broke in Mart
impatiently. "He's a shark, and a big one; pirate or not, if I can't get
to him I'll put a bullet through that big fin of his."

"That's the idea!" exclaimed Bob. "But quit talking or we'll scare him
off. Hit the fin, Mart--don't waste time tryin' to mak