Gib," Stryker said. "You dozed off while we were making planetfall, that's all."

Gibson stiffened resentfully, but Farrell's voice cut his protest short. "Get set! Here they come!"

Out of the morning rainbow dropped a swarm of winged lizards, twenty feet in length and a glistening chlorophyll green in the early light. They stooped like hawks upon the islet offshore, burying the two Arzian fishers instantly under their snapping, threshing bodies. Then around the outcrop the sea boiled whitely, churned to foam by a sudden uprushing of black, octopoid shapes.

"The squids," Stryker grunted. "Right on schedule. Two seconds too late, as usual, to stop the slaughter."

A barrage of barbed tentacles lashed out of the foam and drove into the melee of winged lizards. The lizards took the air at once, leaving behind three of their number who disappeared under the surface like harpooned seals. No trace remained of the two Arzian natives.

"A neat example of dog eat dog," Farrell said, snapping off the magnoscanner. "Do any of those beauties look like city-builders, Gib?"

Chattering pink natives straggled past from the shelter of the thorn forest, ignoring the Earthmen, and lined the casting ledges along the beach to begin their day's fishing.

"Nothing we've seen yet could have built that city," Gibson said stubbornly. "But it's here somewhere, and I'm going to find it. Will either of you be using the scouter today?"

Stryker threw up his hands. "I've a mountain of data to collate, and Arthur is off duty after standing watch last night. Help yourself, but you won't find anything."

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