The scouter was a speeding dot on the horizon when Farrell crawled into his sleeping cubicle a short time later, leaving Stryker to mutter over his litter of notes. Sleep did not come to him at once; a vague sense of something overlooked prodded irritatingly at the back of his consciousness, but it was not until drowsiness had finally overtaken him that the discrepancy assumed definite form. He recalled then that on the first day of the _Marco's_ planetfall one of the pink fishers had fallen from a casting ledge into the water, and had all but drowned before his fellows pulled him out with extended spear-shafts. Which meant that the fishers could not swim, else some would surely have gone in after him. And the Marco's crew had explored Arz exhaustively without finding any slightest trace of boats or of boat landings. The train of association completed itself with automatic logic, almost rousing Farrell out of his doze. "I'll be damned," he muttered. "No boats, and they don't swim. _Then how the devil do they get out to that islet?_" He fell asleep with the paradox unresolved. * * * * * Stryker was still humped over his records when Farrell came out of his cubicle and broke a packaged meal from the food locker. The visicom over the control board hummed softly, its screen blank on open channel. "Gibson found his lost city yet?" Farrell asked, and grinned when Stryker snorted. "He's scouring the daylight side now," Stryker said. "Arthur, I'm going to ground Gib tomorrow, much as I dislike giving him a direct order. He's got that phantom city on the brain, and he lacks the imagination to understand how dangerous to our assignment an obsession of that sort can be." Farrell shrugged. "I'd agree with you offhand if it weren't for Gib's bullheaded habit of being right. I hope he finds it soon, if it's here. I'll probably be standing his watch until he's satisfied." Stryker looked relieved. "Would you mind taking it tonight? I'm completely bushed after today's logging." Farrell waved a hand and took up his magnoscanner. It was dark outside already, the close, soft night of a moonless tropical world whose moist atmosphere absorbed even starlight. He dragged a chair to the open port and packed his pipe, settling himself comfortably while Stryker mixed a nightcap before turning in. Later he remembered that Stryker dissolved a tablet in his glass, but at the moment it meant nothing. In a matter of minutes the older man's snoring drifted to him, a sound faintly irritating against the velvety hush outside. Farrell lit his pipe and turned to the inconsistencies he had uncovered. The Arzians did not swim, and without boats.... It occurred to him then that there had been two of the pink fishers on the islet each morning, and the coincidence made him sit up suddenly, startled. Why two? Why not three or four, or only one?