I first heard a shout. Then so help me, a Bengal tiger was charging us.

Probably Mary got in the first shot. I know that mine was not behind that of the young officer; it might even have been ahead. I'm sure it was-fairly sure, anyhow. It was the Old Man who shot last.

Among the four of us we cut that beast so many ways that it would never be worth anything as a rug. And yet the slug on it was untouched; I fried it with my second bolt. The young fellow looked at it without surprise. "Well," he said, "I thought we had cleaned up that load."

"Huh? What do you mean?"

"One of the first transport tanks they sent out. Regular Noah's Ark. We were shooting everything from gorillas to polar bears. Say, did you ever have a water buffalo come at you?"

"No and I don't want to."

"Not near as bad as the dogs, really. If you ask me, those things don't have much sense." He looked at the slug, quite unmoved, while I was ready as usual to throw up.

We got up out of there fast and onto the titan ship-which did not make me less nervous, but more. Not that there was anything frightening in the ship itself, not in its appearance.

But its appearance wasn't right. While it was obviously artificial, one knew without being told that it was not made by men. Why? I don't know. The surface of it was dull mirror, not a mark on it-not any sort of a mark; there was no way to tell how it had been put together. It was as smooth as a Jo block.

I could not tell of what it was made. Metal? Of course, it had to be metal. But was it? You would expect it to be either bitterly cold-or possibly intensely hot from its landing. I touched it and it was not anything at all, neither cold nor hot. Don't tell me it just happened to be exactly ninety-eight and six-tenths. I noticed another thing presently; a ship that size, landing at high speed, should have blasted a couple of acres. There was no blast area at all; the brake around it was green and rank.

We went up to the parasol business, the air lock, if that is what it was. The edge was jammed down tight on the little mud turtle; the armor of the tank was crushed in, as one might crush a pasteboard box with the hand. Those mud turtles are built to launch five hundred feet deep in water; they are strong.

Well, I suppose this one was strong. The parasol arrangement had damaged it, but the air lock had not closed. On the other hand the metal, or whatever the spaceship's door was made of, was unmarked by the exchange.

The Old Man turned to me. "Wait here with Mary."

"You're not going in there by yourself?"

"Yes. There may be very little time."

The kid spoke up. "I'm to stay with you, sir. That's what the commander said."

"Very well, sir," the Old Man agreed. "Come along." He peered over the edge, then knelt and lowered himself by his hands. The kid followed him. I felt burned up-but had no desire to argue the arrangements.

They disappeared into the hole. Mary turned to me and said, "Sam-I don't like this. I'm afraid."

She startled me. I was afraid myself-but I had not expected her to be. "I'll take care of you."

"Do we have to stay? He did not say so, quite."

I considered it. "If you want to go back to the car I'll take you back."

"Well . . . no, Sam, I guess we have to stay. Come closer to me." She was trembling.

I don't know how long it was before they stuck their heads over the rim. The youngster climbed out and the Old Man told him to stand guard. "Come on," he said to us, "it's safe-I think."

"The hell it is," I told him, but I went because Mary was already starting. The Old Man helped her down.

"Mind your head," he said. "Low bridge all the way."

It is a platitude that unhuman races produce unhuman works, but very few humans have ever been inside a Venerian labyrinth and still fewer have seen the Martian ruins-and I was not one of the few. I don't know what I expected. Superficially the inside of the saucer was not, I suppose, too startling, but it was strange. It had been thought out by unhuman brains, ones which did not depend on human ideas in fabricating, brains which had never heard of the right angle and the straight line or which regarded them as unnecessary or undesirable. We found ourselves in a very small oblate chamber and from there we crawled through a tube about four feet thick, a tube which seemed to wind down into the ship and which glowed from all its surface with a reddish light.

The tube held an odd and somewhat distressing odor, as if of marsh gas, and mixed with it faintly was the reek of dead slugs. That and the reddish glow and the total lack of heat response from the wall of the tube as my palms pressed against it gave me the unpleasant fancy that I was crawling through the gut of some unearthly behemoth rather than exploring a strange machine.

The tube branched like an artery and there we came across our first Titanian androgyne. He-let me call it "he"-was sprawled on his back, like a child sleeping, his head pillowed on his slug. There was a suggestion of a smile on the little rosebud mouth; at first I did not realize that he was dead.

At first sight the similarities between the Titanian people and ourselves are more noticeable than the differences; we impress what we expect to see on what we do see, as a wind-sculptured rock may look like a human head or a dancing bear. Take the pretty little "mouth" for example; how was I to know that it was an organ for breathing solely?

Conceded that they are not human and that, despite the casual similarities of four limbs and a head-like protuberance, we are less like them than is a bullfrog like a bullpup; nevertheless the general effect is pleasing, not frightening, and faintly human. "Elfin" I should say-the elves of Saturn's moons. Had we met them before the slugs we call titans possessed them I think we could have gotten along with them. Judged by their ability to build the saucers they were our equals-if they did build them. (Certainly the slugs did not build them; slugs are not builders but thieves, cosmic cuckoos.)

But I am letting my own later thoughts get in the way. When I saw the little fellow I managed to draw my gun. The Old Man, anticipating my reaction, turned and said, "Take it easy. It's dead-they are all dead, smothered in oxygen when the tank ruined their air seal."

I still had my gun out. "I want to burn the slug," I insisted. "It may still be alive." It was not covered by the horny shell we had lately come to expect but was naked, moist and ugly.

He shrugged. "Suit yourself. It can't possibly hurt you."

"Why not?"

"Wrong chemistry. That slug can't live on an oxygen breather." He crawled across the little body, giving me no chance to shoot had I decided to. Mary, always so quick with a gun, had not drawn but had shrunk against my side and was breathing in sharp little sobbing gasps. The Old Man stopped and said patiently, "Coming, Mary?"

She choked and then gasped, "Let's go back! Let's get out of here!"

I said, "She's right. This is no job for three people; this is something for a research team and proper equipment."

He paid no attention to me. "It has to be done, Mary. You know that. And you have to be the one to do it."

"Why does she have to do it?" I demanded angrily.

Again he ignored me. "Well, Mary?"

From somewhere inside herself she called on reserves. Her breathing became normal, her features relaxed, and she crawled across the slug-ridden elfin body with the serenity of a queen going to the gallows. I lumbered after them, still hampered by my gun and trying not to touch the body.

We came at last to a large chamber. It may have been the control room, for there were many of the dead little elfin creatures in it, though I saw nothing resembling (to my eye) instruments or machinery. Its inner surface was cavitated and picked out with lights much brighter than the reddish illumination and the chamber space was festooned with processes as meaningless to me as the convolutions of a brain. I was troubled again with the thought-completely wrong, I know now-that the ship itself was a living organism.