Just behind the wreck the rock wall rose abruptly to the surface of the reef. Its base was hollowed into a series of low caves, where masses of softer rock had been eaten out from beneath a slanting stratum of more enduring material. The most spacious of these caves was immediately behind the wreck. It was exactly what the monster craved. He backed into it with alacrity, completely filling it with his spectral and swollen body. In the doorway the convex inky lenses of his eyes kept watch, moveless and all-seeing. And his ten pale-spotted tentacles, each thicker at the base than a man's thigh, lay outspread and hidden among the seaweeds, waiting for such victims as might come within reach of their lightning snap and coil.

The monster had no more than got himself fairly installed in his new quarters, when into the range of his awful eyes came a singular figure, descending slowly through the glimmering green directly over the wreck. It was not so long as the swordfish he had lately swallowed, but it was thick and massive-looking; and it was blunt at the ends, unlike any fish he had ever seen. Its eyes were enormous, round and bulging. From its head and from one of its curious round, thick fins, extended two slender antennæ straight up toward the surface, and so long that their extremities were beyond the monster's vision. It was indeed a strange-looking creature, but he felt sure that it would be very good to eat. In their concealment among the many-coloured seaweeds his tentacles thrilled with expectancy, and he waited, like some stupendous nightmare of a spider, to spring the moment the prey came within reach.

It chanced, however, that just as the strange creature, descending without any movement of its fins, did come within reach, there also appeared again, in the distance, the black form of the "killer" whale, swimming far overhead. The monster changed his plans instantly. His interest in the newcomer died out. He became intent on nothing but keeping himself inconspicuous. The newcomer, unconscious of the terror lying in wait so near him and of the dark form patrolling the upper green, alighted upon the wreck and groped his way lumberingly into the cabin, dragging those two slim antennæ behind him.

IV

When Jan Laurvik, in his up-to-date and well-tested diving-suit, went down through the green twilight of the sea, he was doing what it was his profession to do, and he had few misgivings. He had confidence in his equipment, in his skill, and in his mate at the rope and the air-pump, Captain Jerry. For defence against any obtrusive shark or sawfish he carried a heavy, long-bladed, two-edged knife, by far the most effective weapon in deep water. This knife he wore in a sheath at his waist, with a cord attached to the handle so that it could not get away from him. He carried also a tiny electric battery supplying a strong lamp on the front of his head-piece just above his eyes.

From his long experience in sounding and in locating wrecks, Jan Laurvik had acquired an accuracy that seemed almost like divination. His soundings, in this instance, had been particularly thorough, because he did not wish to waste any more time than necessary at the depth in which he would have to work. He was not surprised, therefore, when he found himself descending upon the wreck of a junk. Moreover, as it was not an old wreck, he concluded that it was the junk which he was looking for. The wreck had settled almost on an even keel; and as he was familiar with craft of her type, he had no difficulty in finding his way about.

It was in the narrow, closet-like structure which served as the junk's cabin that the pirate had said the pearls would be found. The door was open. Turning on his light, which struggled with the water and diffused a ghostly glow, he found himself confronted by a hideous little joss of red-and-gilt lacquer. He knew it was lacquer, and of the best, for nothing else, except gold itself, would have withstood the months of soaking in sea-water. Jan grinned to himself, there within his rubber and copper shell, at this evidence of pirate piety. Then it occurred to him that a man like the pirate captain would probably have turned his piety to practical use. What better guardian of the treasure than a god? Dragging the gaudy deity from his altar, he found the altar hollow. In that secure receptacle lay a series of packages done up with careful precision in wrappings of oiled silk. He knew the style of wrapping very well. For all his coolness, his heart fell to thumping painfully at the sight of this vast wealth beneath his hand. Then he realized that the pressure of the water, and of the compressed air in his helmet, was beginning to tell upon him. In fierce but orderly haste he corded the packages about his middle and turned to leave the cabin. He would make another trip for the lacquer god, and for such other articles of value or vertu which the junk might contain.

Jan turned to leave the cabin. But in the doorway he started back with a shudder of dread and loathing. A slender, twisting thing, whitish in colour and minutely speckled with livid spots, reached in, and fastened upon his arm with soft-looking suckers which held like death.

Jan knew instantly what the pale, writhing thing was. Out flashed his knife. With a swift stroke he slashed off the detaining tip, where it had a thickness of perhaps two inches. The raw stump shrank back, like a severed worm, and Jan, leaping clear of the doorway, signalled furiously to be hauled up. But at the same instant two more of the curling white things came reaching over the bulwarks and fastened upon him—one upon his right arm, hampering him so that he was almost helpless, and the other upon his left leg just above the knee. He felt his signal promptly answered by a powerful tug on the rope. But he was anchored to the wreck as if he had grown to it.

Never before had Jan Laurvik felt the clutch of fear at his heart as he did at this moment. But not for an instant, in the horror, did he lose his presence of mind. He knew that in a pulling match with the giant devil-fish of the deeps his comrades in the boat far overhead would be nowhere. He had made a mistake in leaving the cabin. Frantically he signalled with his left hand, to "slack away" on the rope; and at the same time, though hampered by the grip on his right arm, he managed to slash off the end of the feeler that had fixed upon his leg. On the instant, whipping the knife over to his left, he cut his right arm clear, and sprang back into the doorway.