e the bullet
penetrate the water unless we get up close alongside."

Mart, quivering with excitement, got a bead on that tremendous black fin
which was now turning as if to proceed across their bows. It would be
futile to attempt shooting the shark at such a distance, for as Bob said
the bullet would simply glance from the surface of the water.

Suddenly Mart perceived that the fin was turning away from them.
Instantly he sighted for its center, made sure of his bead, and fired.
He saw the fin flutter wildly, then there was a great swirl of waters,
and as the heavy detonation rang over the lagoon the black fin vanished
amid the foam.

"Hit!" yelled Bob. "There are the men, Mart!"

Indeed, the figures of the three seaman were visible, running down the
sand, and Mart waved a hand at the yacht as he sat down, for he knew
that Swanson and the captain would be watching. But the greatest thought
in his mind was that black fin. The Pirate Shark was a reality! They had
seen its "black flag" and he had sent a bullet through it!

None of the three spoke as they pulled the heavy boat in to the beach
where the men waited. As they approached, the three seamen splashed out
and piled aboard, Mart taking his place again in the stern. The first
question, naturally, was for the cause of the firing.

"We saw the Pirate Shark," answered Dailey. "We put a bullet through its
fin."

"Huh?" one incredulous cry broke from the other three. "Who fired it?"

"Mr. Judson done it."

Three pairs of eyes swept to Mart, who laughed at the amazement of the
men. "Well, why not?" he wanted to know.

"Great Scott!" exclaimed Birch. "You fired on the Pirate Shark, lad?
Then I'm main sorry for you, that I am!"

"Why so, Birch?" queried Bob, leaning forward and grinning.

"Because it's bad luck, young gem'man," replied Yorke soberly enough,
for all his twisted mouth. "It's mortal bad luck! If you'd put a bullet
in that there Pirate Shark, you'd 'a' broke old Jerry's heart, you
would--"

"Oh, shut up, Yorke!" snapped Birch. "Give way, everybody! There's a
boat!"

The boys turned and saw one of the native praus coming from the river
toward the yacht. The superstition of the seamen affected them not at
all, and Mart felt that all bans were now off, and they could tell
Captain Hollinger about the Pirate Shark whenever they chose. Jerry was
no doubt aboard the native boat now approaching--and Mart did not feel
half so anxious to shoot tigers as h