Dave expressed his feelings in one round oath, which, being uttered in his native dialect, sounded to Billy “Like gargling the throat.”

It needed no expletives to inform Billy that the dog’s appearance on the scene of action was certain to cause trouble.

“Ketch um dog, choke um!” said Dave, looking about him to see if the barking had brought anyone to the place.

“Where is the cur?” Billy asked.

“Don’t see um,” replied the Seminole.  He straightened up until his head was above the top of the grass.  “A-ah!” he exclaimed in a guttural tone.  “Man in sailboat yonder.”

Impulsively Billy scrambled to a kneeling position, and his gaze followed Dave’s.  The two spies then beheld the figure of a man seated in the stern of a dug-out canoe that carried a mast and sail and was coming around the bend of a stream.

“If he sees us-----” began Billy.

“S-s-sh!” Dave interrupted warningly.  “Wait, see where he go.”

“Is the dog barking at us or at him?  What d’you think, Dave?”

“At us,” was the answer.  “Man come, let dog loose,—–­we better go back!  Incah!”

“No,” said Billy firmly.  “Dog or no dog, I’m not going back till I’ve found out where they’ve hidden Hugh!”

If Billy had only known that Hugh was locked in that further cabin!  If Hugh had only been able to communicate with his friends on picket duty!  How much trouble would have been avoided,—–­yet what an adventure they would have missed!

Dave now explained to Billy that his purpose had been to purloin the sailing canoe, so that the smugglers on shore would be dependent on a boat from the Esperanza to take them and their goods away.  This would enable the crew of the Petrel to intercept the smugglers as soon as they landed.  But now, with the appearance of this man in the canoe, Dave’s plan seemed about to be thwarted.

* * * * * *

Meanwhile, what of the others who remained on the peninsula?

More than an hour passed before any one saw a suspicious figure on the landscape.  Then Alec, whose post was farthest removed from the landing place, suddenly caught sight of two men walking along the shore.  They were carrying the same battered tin box which he and Billy had found half buried in the sand, many hours ago.  Evidently the box was heavy, for they appeared to stagger with its weight.

Alec raised his voice in the weird, low call of the otter.  As his patrol was named after that animal, he knew that Chester, also of the Otter patrol, would recognize the signal.  In this case it meant “Danger.  Look around you.”

From a distance, hidden behind a clump of palmettos, Chet responded with the same call twice, in quick succession.

But the men carrying the box heard the calls.  They knew it was still too early in the afternoon for otters to be hunting so noisily, and they were surprised, startled, suspicious.  To Alec’s dismay, they dropped the box, stood still, and stared all around them.  Alec lay flat on the ground, trusting that his khaki suit and brown flannel shirt would help him to escape observation.  At the same time he dread lest one of the other pickets would be seen too soon.