“No,” replied Tom, “I can’t see a single white thing there—all I see are bright colored weeds and sea-fans and rocks.”

The negro looked genuinely surprised. “Bless yo’ soul!” he exclaimed. “Yo’ cawnt be a s’archin’ fo’ white coral is yo’? White coral’s jus’ dead coral, Chief. Tha’s da culmination o’ tha’ manner o’ it’s prep’ration, Chief. Yaas, sir, all tha’ objec’s yo’ di’sarn growin’ down to tha’ bottom is corals, Chief. Yaas, sir, some of tha’ kin’s is yellow an’ some red an’ some green.”

It was the boys’ turn to be surprised. “Why, you don’t mean all those things like stones covered with bright-colored weeds are coral!” exclaimed Frank incredulously.

“Yaas, sir, Chief,” the negro assured him. “Ah’ll demonstrate it to yo’ entire satisfaction, Chief.”

As he spoke, the half-naked negro stood up in the little craft and before the astonished boys realized what he was about to do he had plunged into the clear water and the boys watched in wonder as they saw him swimming easily straight towards the bottom, a little string of bubbles rising from him and the pink soles of his feet flashing strangely. In an instant he had reached the masses of growth on the sea floor and the boys saw him pulling and working at a projecting ledge of vivid violet and green. Then he turned and shot up to the surface like a flash. As he broke through the water he tossed a large lump of brilliant material into the boat and clambered over the stern.

Interestedly the boys examined what he had brought and to their absolute amazement discovered that it really was coral, but as the man explained, completely concealed under the fleshy covering of the animals which resembled tiny sea anemones of wonderful tints.

But after their first momentary surprise and interest at the discovery the two boys found much more to attract them in the denizens of the mass of coral than in the coral itself. Odd red and white crabs emerged from their hiding places, a tiny fish that glittered with the dazzling hues of a fire opal flapped from under a bit of adhering seaweed, funny slug-like molluscs of intense blue and gold crawled about the mass, queer little snails were everywhere and when the boys disturbed the coral or handled it they heard odd snapping noises like lilliputian firecrackers.

For a time this puzzled them until Frank discovered to his intense delight that the sounds were made by tiny lobster-like crustaceans that dwelt in holes in the hard coral and viciously snapped their claws when disturbed.

“Say,” asked Tom presently, “weren’t you afraid of a devil fish—octopus, you know—down there?”

“Bless your soul, no, Chief!” grinned the negro. “Tha’ fellow doan’ never humbug us. We eats them down here, Chief.”