"Quite simple to explain," the old professor had replied. "Any creature who can live at the frightful pressures of the ocean depths could never survive a journey even halfway to the surface. It would be like our trying to live in an almost perfect vacuum. We should explode, and so would these denizens of the deep, if they tried to come up here. Even one of their dead bodies could not be brought to the surface in recognizable form. No contact with them will ever be possible, nor will they ever constitute a menace to any one--for which we may thank the Lord!" George Abbot now reviewed this conversation as he crouched in his diving-sphere in the purple darkness of the marine depths. Yes, old Osborne would believe him. The diary must be written for Osborne's eyes. * * * * * Abbot sent another beam from his pocket light suddenly out into the water; and this time he surprised several of the peculiar fish. These, like the first, had arms and hands and high intelligent foreheads. Then suddenly Abbot laughed a harsh laugh. Old Osborne had been wrong in one thing, namely in saying that the super-race of the deep would never be a menace to anyone. They were being a menace to George Abbot, right now, for it was undoubtedly they who had cut his cables. Probably they were possessed of much the same scientific curiosity with regard to him as he was with regard to them, and so they had determined to secure him as a museum specimen. The idea was a weird one. He laughed again, mirthlessly. "What is the matter, sir?" came an anxious voice in his ear-phones. "Hurry that grapple!" was his reply. "I have found out what cut my cables. There are some very intelligent-looking fish down here, and I think they want me for--" An ominous click sounded in his ears. Then silence. "Hello! Hello there!" he shouted. "Can you hear me up on the boat?" But no answer came back. The line remained dead. The strange fish had cut George Abbot's last contact with the upper world. The grapple-hooks could never find him now, for there was now not even a telephone cable to guide them down to his sphere. The realization that he was hopelessly lost, and that he had not much longer to live, came as a real relief to him, after the last few moments of frantic uncertainty. * * * * * Hoping that his sphere would eventually be found, even though too late to do him any good, he set assiduously to work jotting down all the details which he could remember of those strange denizens of the deep, the man-handed sharks, which he was now firmly convinced were the cause of his present predicament. He stared out through one of his windows into the brilliant blue darkness, but did not turn on his flashlight. How near were these enemies of his, he wondered?