Toward this ledge Grom now led the way, hurling himself through the water on his side at top speed. He could not fathom this mysterious phosphorescence, and he wished to get his people out upon dry land before it reached them. But fast as the adventurers swam, the ghostly radiance spread faster. Before they got to the ledge, the light was all about them; but it seemed to be coming from a great depth. Nervously they all glanced down, and a low cry of horror broke from their lips. The depths were swarming with monstrous, luminous forms, a moon-bright, crawling, sliding field of claws and feelers, and broad, flat backs, and dreadful, protruding eyes. The eyes all stared straight up at them with a fixed malignancy that froze even Grom's blood. They seemed innumerable, and all together they came suddenly floating upwards. Already the fugitives were dragging themselves out upon the ledge, in frantic haste, when the diabolical swarm reached the surface. But Hobbo, who was the slowest swimmer, was merely clutching at the rock when the water boiled all about him in a froth of light. A pair of huge, pincer-like claws seized him by the neck, and another pair by one arm, plucking him back. His convulsed face stared upward for an instant, and then, with a choked scream, he was dragged under. He disappeared in a swirl of pale blue, frantically waving claws, and eyes, and feelers, and black-fringed, chopping mouths. Beside himself with rage and horror, Grom stabbed down wildly into the whirling struggle, and his example was followed at once by Loob and young Mo. Some of their random blows went home, and as one or another of the gigantic crabs turned over in its death-throes, its nearest fellows seized it, tore it to pieces, and devoured it. But A-ya, who had taken no part in this vengeance, now snatched Grom by the arm, shrieking wildly: "Look! They are coming out!" Recovering their senses, the three half-maddened men stared about them. On every side the gigantic crabs--some with claws eight or ten feet long, and eyes upon the ends of long waving stalks--were crawling up upon the ledge. The ledge, fortunately, was of some width. At its landward end it rose into a mass of tumbled rocks perhaps twenty or thirty feet above the water. Toward this post of vantage the adventurers fought their way, striking and thrusting desperately with their spears as the monsters, crowding up from the water on either side, snatched at them with their terrible mailed claws. Over and over again one or another of the party was seized by the foot or the leg; but his companions would beat the long, jointed limb to fragments, or drive their spear-points deep into the awful, drooling mouth, and set him free.