Slowly his racing heartbeat returned to normal. Gradually he became aware of the stench of decaying plants and of musky taints he knew instinctively were the scents of underwater animals. Then with a shock the meaning became clear. He had become a water-breather, cut off from all other Earthmen, no longer entirely human. His fellows in the colony were separated from him now by a gulf more absolute than the airless void between Earth and Venus. Something slippery and alive touched him near one armpit. He opened his eyes in the black water and his groping hand clutched something burrowing into his skin. With a shudder of revulsion he crushed a fat worm between his fingers. Then dozens of them--hundreds--were upon him from all sides. He was wearing only a pair of khaki pants but the worms ignored his chest to congregate around his face, intent on attacking the tender skin of his eyelids. For a minute his flailing hands fought them off, but they came in increasing numbers and clung like leeches. Pain spread as they bit and burrowed, and blindly he began to swim. Faster and faster. He could sense the winding banks of the slough and kept to midchannel, swimming with his eyes tightly closed. One by one the worms dropped off. He stopped, opened his eyes, not on complete darkness this time but on a faint blue-green luminescence from far below. The water was saltier here, and clearer. He had swum down the slough and out into the ocean. He tried to turn back, obsessed by a desire to be near the colony even though he could not go ashore without strangling, but he had lost all sense of direction. He was still weak and his lungs were not completely adjusted to underwater life. Again he grew dizzy and faint. The slow movements of hands and feet that held him just below the surface grew feeble and ceased. He sank. Down into dimly luminous water he dropped, and with his respiratory system completely water-filled there was no sensation of pressure. At last he floated gently to the bottom and lay motionless. Shouting voices awakened him, an exultant battle cry cutting through a gasping scream of anguish. Streaks of bright orange light were moving toward him in a twisting pattern. At the head of each trail was a figure. A human figure that weaved and swam in deadly moving combat. One figure drifted limply bottomward. Hallucination, Barry told himself. Then one of the figures broke from the group. Almost overhead it turned sharply downward and the feet moved in a powerful flutter-kick. A slender spear aimed directly at the Earthman. Barry threw himself aside. The spear point plunged deep into the sticky, yielding bottom and Barry grappled with its wielder. Pointed fingernails raked his cheek. Barry's balled fist swung in a roundhouse blow but water resistance slowed the punch to ineffectiveness. The creature only shook its head and came in kicking and clawing.