Davis made an irresolute gesture. He seemed to hesitate over something he was inclined to accept. Deirdre protested before he could speak. "I don't think what you're thinking is right!" she said firmly. "Not a bit of it! Whatever happens will be connected with the fish. _La Rubia_ has been around this sort of thing over and over again! We haven't been running the engine and we haven't been making any specific noises in the water to arouse curiosity! If anything were going to happen to us, it would have happened to _La Rubia_ before now! It would be ridiculous to run away just because I'm on board!" Terry, bent intently over the recorder, suddenly felt a cold chill run up and down his spine. His mind told him it was ridiculous to associate distant mooing sounds, underwater, with a completely unprecedented, frantic gathering of fish into one small area, and come up with the thought that something monstrous and plaintive was coming blindly to feed upon fellow creatures of the sea. There was nothing to justify the thought. It was out of all reason. But his spine crawled, just the same. "The circle's only eight hundred yards across, now," said Davis, uneasily. "The fish can't crowd together any closer! But Doug went overboard with diving goggles, and he says there's a column of brightness as far down as he can make out." Terry looked up. "He went overboard? Didn't he tingle?" "He said it was like baby nettles all over," Davis protested, as if it were someone's fault. "But he didn't sting after he came out. It must be ..." A mooing sound came out of the recorder. It was fainter than the other sounds and very far away. It must have been of terrific volume where it originated. It lasted for many seconds, then stopped. "I should have been recording," said Terry. "That sound comes up about every five minutes. I'll catch it next time." Davis went away, as if he wanted to miss the noise and the decision it would force upon him. Yet Terry told himself obstinately that there was no reason to connect the mooing sound with the crazed fish herd half a mile away. But somehow he couldn't help thinking there might be a connection. The ship's clock sounded seven bells. Deirdre said, "The brightness is really smaller now!" The patch of flashes was no more than half its original size. Terry pressed the recording button and straightened up to look more closely. Right then Deirdre said sharply, "Listen!" Something new and quite unlike the mooing noise now came out of the recorder. "Get your father," commanded Terry. "Something's coming from somewhere!" Deirdre ran across the heaving deck. Terry shifted position so he could manipulate the microphone hanging over the yacht's side into the water. Davis arrived. His voice was suddenly strained and grim. "Something's coming?" he demanded. "Can you hear any engine noise?" "Listen to it," said Terry. "I'm trying to get its bearing."