Dr. Stone found them, ran through them, and required him to send some of them back. The rest passed her censorship; they took them along.

The last episode was speeding toward Earth; the last weld had been approved; the last pound of food and supplies was at last aboard. The Stone lifted gently from Phobos and droppedtoward Mars. A short gravity-well maneuver around Mars at the Stone's best throat temperature - which produced a spine-grinding five gravities - and she was headed out and fast to the lonely reaches of space inhabited only by the wreckage of the Ruined Planet.

"They fell easily and happily back into free fall routine. More advanced mathematical texts had been obtained for the boys on Mars; they did not have to be urged to study, having grown really interested - and this time they had no bicycles to divert their minds. Fuzzy Britches took to free fall if the creature had been born in space; if it was not being held and stroked by someone (which it usually was) it slithered over wall and bulkhead, or floated gently around the compartments, undulat­ing happily.

Castor maintained that it could swim through the air; Pollux insisted that it could not and that its maneuvers arose entirely from the air currents of the ventilation system, They wasted considerable time, thought, and energy in trying to devise scientific tests to prove the matter, one way or the other. They were unsuccessful.

The flat cat did not care; it was warm, it was well fed, it was happy. It had numerous friends all willing to take time off to reward its tremendous and undiscriminating capacity for affec­tion. Only one incident marred its voyage.

Roger Stone was strapped to his pilot's chair, blocking out - so he said - a chapter in his book. If so, the snores may have helped. Fuzzy Britches was cruising along about its lawful occasions, all three eyes open and merry. It saw one of its friends; good maneuvering or a random air current enabled it to make a perfect landing - on Captain Stone's face.

Roger came out of the chair with a yell, clutching at his face. He bounced against the safety belt, recovered, and pitched the flat cat away from him. Fuzzy Britches, offended but not hurt, flipped itself flat to its progress, air-checked and made another landing on the far wall.

Roger Stone used several other words, then shouted, "Who put that animated toupee on my face?"

But the room was otherwise empty. Dr. Stone appeared at the hatch and said, "What is it, dear?"

"Oh, nothing - nothing important. Look, dear, would you return this tailend offspring of a dying planet to Buster? I'm trying to think."

"Of course, dear." She took it aft and gave it to Lowell, who promptly forgot it, being busy working out a complicated gambit against Hazel. The flat cat was not one to hold a grudge; there was not a mean bone in its body, had it had bones, which it did not The only emotion it could feel whole­heartedly was love. It got back to Roger just as he had. again fallen asleep.

It again settled on his face, purring happily.

Captain Stone proved himself a mature man. Knowing this time what it was,.he detached it gently and himself returned it to Lowell. "Keep it," he said. "Don't let go of it." He was careful to close the door behind him.

He was equally careful that night to close the door of the stateroom he shared with his wife. The Rolling Stone, being a small private ship, did not have screens guarding her ventila­tion ducts; they of course had to be left open at all times. The flat cat found them a broad highway. Roger Stone had a nightmare in which he was suffocating, before his wife woke him and removed Fuzzy Britches from his face. He used some more words.

"It's all right, dear," she answered soothingly. "Go back to sleep." She cuddled it in her arms and Fuzzy Britches settled for that.

The ship's normal routine was disturbed the next day while everyone who could handle a wrench or a spot welder installed screens in the ducts.

Thirty-seven days out Fuzzy Britches had eight golden little kittens, exactly like their parent but only a couple of inches across when flat, marble-sized when contracted. Everyone, including Captain Stone thought they were cute; everyone enjoying petting them, stroking them with a gentle forefinger and listening carefully for the tiny purr, so high as to be almost beyond human ear range. Everyone enjoyed feeding them and they seemed to be hungry all the time.

Sixty-four days later the kittens had kittens, eight each. Sixty-four days after that, the one hundred and forty-sixth day after Phobos departure, the kittens' kittens had kittens; that made five hundred and thirteen.

"This," said Captain Stone, "has got to stop!"

"Yes, dear."

"I mean it At this rate we'll run out of food before we get there, including the stuff the twins hope to sell. Besides that we'll be suffocated under a mass of buzzing fur mats. What's eight times five hundred and twelve? Then what's eight times that?"

"Too many, I'm sure."

"My dear, that's the most masterly understatement since the death of Mercutio. And I don't think I've figured it properly anyway; its an exponential expansion, not a geometric - pro­vided we don't all starve first"

"Roger."

"I think we should-Eh? What?"

"I believe there is a simple solution. These are Martian creatures; they hibernate in cold weather."

"Yes?"

"We'll put them in the hold - fortunately there is room."

"I agree with all but the "fortunately.""

"And we'll keep it cold."

"I wouldn't want to kill the little things. I can't manage to hate them. Drat it, they're too cute."

"We'll hold it about a hundred below, about like a normal Martian winter night. Or perhaps warmer will do."

"We certainly will. Get a shovel. Get a net Get a barrel." He began snagging flat cats out of the air.

"You aren't going to freeze Fuzzy Britches!" Lowell was floating in the stateroom door behind them, clutching an adult flat cat to his small chest. It may or may not have been Fuzzy Britches; none of the others could tell the adults apart and naming had been dropped after the first litter. But Lowell was quite sure and it did not seem to matter whether or not he was right The twins had discussed slipping in a ringer on him while he was asleep, but they had been overheard and the project forbidden. Lowell was content and his mother did not wish him disturbed in his belief.

"Dear, we aren't going to hurt your pet"

"You better not! You do and I'll - I'll space you!"

"Oh, dear, he's been helping Hazel with her serial!" Dr. Stone got face to face with her son. "Lowell, Mother has never lied to you, has she?"

"Uh, I guess not"

"We aren't going to hurt Fuzzy Britches. We aren't going to hurt any of the flat kitties. But we haven't got room for all of them. You can keep Fuzzy Britches, but the other kittens, are going for a long nap. They'll be perfectly safe; I promise.

"By the code of the Galaxy?"

"By the code of the Galaxy."

Lowell left, still guarding his pet. Roger said, "Edith, we've got to put a stop to that collaboration."

"Don't worry dear; it won't harm him." She frowned. "But I'm afraid I will have to disappoint him on another score."

"Such as?"

"Roger, I didn't have much time to study the fauna of Mars - and I certainly didn't study flat cats, beyond making sure that they were harmless."

"Harmless!" He batted a couple of them out of the way. "Woman, I'm drowning."

"But Martian fauna have certain definite patterns, survival adaptations. Except for the water-seekers, which probably aren't Martian in origin anyhow, their methods are both pas­sive and persistent. Take the flat cat-"