Some fifty million years ago, when the planet that had been called Zarathustra (for the last twenty-five million) was young, there had existed a marine life form, something like a jellyfish. As these died, they had sunk into the sea-bottom ooze; sand had covered the ooze and pressed it tighter and tighter, until it had become glassy flint, and the entombed jellyfish little beans of dense stone. Some of them, by some ancient biochemical quirk, were intensely thermofluorescent; worn as gems, they glowed from the wearer's body heat. On Terra or Baldur or Freya or Ishtar, a single cut of polished sunstone was worth a small fortune. Even here, they brought respectable prices from the Zarathustra Company's gem buyers. Keeping his point of expectation safely low, he got a smaller vibrohammer from the toolbox and began chipping cautiously around the foreign object, until the flint split open and revealed a smooth yellow ellipsoid, half an inch long. "Worth a thousand sols--if it's worth anything," he commented. A deft tap here, another there, and the yellow bean came loose from the flint. Picking it up, he rubbed it between gloved palms. "I don't think it is." He rubbed harder, then held it against the hot bowl of his pipe. It still didn't respond. He dropped it. "Another jellyfish that didn't live right." Behind him, something moved in the brush with a dry rustling. He dropped the loose glove from his right hand and turned, reaching toward his hip. Then he saw what had made the noise--a hard-shelled thing a foot in length, with twelve legs, long antennae and two pairs of clawed mandibles. He stopped and picked up a shard of flint, throwing it with an oath. Another damned infernal land-prawn. He detested land-prawns. They were horrible things, which, of course, wasn't their fault. More to the point, they were destructive. They got into things at camp; they would try to eat anything. They crawled into machinery, possibly finding the lubrication tasty, and caused jams. They cut into electric insulation. And they got into his bedding, and bit, or rather pinched, painfully. Nobody loved a land-prawn, not even another land-prawn. This one dodged the thrown flint, scuttled off a few feet and turned, waving its antennae in what looked like derision. Jack reached for his hip again, then checked the motion. Pistol cartridges cost like crazy; they weren't to be wasted in fits of childish pique. Then he reflected that no cartridge fired at a target is really wasted, and that he hadn't done any shooting recently. Stooping again, he picked up another stone and tossed it a foot short and to the left of the prawn. As soon as it was out of his fingers, his hand went for the butt of the long automatic. It was out and the safety off before the flint landed; as the prawn fled, he fired from the hip. The quasi-crustacean disintegrated. He nodded pleasantly. "Ol' man Holloway's still hitting things he shoots at."