His descent was momentarily stayed by a piece of rotten log about the size of his own body, which projected from the side of the crater, and with which he came in contact; but finally his struggles loosened it, and it bounded down the slope ahead of him. As he slid after it, he instinctively watched its downward course. It rolled to the exact center of the bottom of the pit; and as it came to a stop, the sand beneath it heaved convulsively, and from each side of it rose out of the ground a glittering scimitar fully ten feet long, which closed upon the log like the blades of a pair of buttonhole scissors, and dragged it beneath the surface. A moment later, and Cabot himself rolled to the exact spot where the log had been seized and had disappeared. Like a flash he realized the full extent of his predicament. He had fallen into the trap of a gigantic ant-bear. Years ago, as a boy at Atlantic City, he had often lain on the piazza floor of the bathhouse and watched through the cracks the antics of the miniature beasts of prey in the sand below. He had seen them dig their pits; two or three inches across; he had seen them plow a trail to their pits; he had seen inquisitive beach ants, in search of food, follow these trails, fall into the pit, and be dragged struggling beneath the surface, to furnish a meal for the ant bear which lay in wait, buried in the center of the depression which it had dug. But never had he pictured himself as falling into one of these traps. Was he in one now? It could hardly be. And yet, as there were huge ants ten feet long on Poros, and also slightly smaller breeds without the intelligence which characterized the Formians, why not ant-bears in proportion? It certainly sounded plausible. Of course, these thoughts, which take so long to set down here, passed through Cabot’s brain in a single instant. He felt no fear, merely a keen scientific interest in the situation. But, quickly as his mind worked to analyze his predicament, it worked as quickly to determine a course of action. The subterranean beast spewed up the unappetizing log of wood which it had seized, and snapped its mandibles together again; but Cabot had already sprung to his feet, and had passed beyond the fatal spot. The sharp jaw just barely missed him. His bound carried him part way up the opposite side, but almost immediately he started slipping back again into the center. This time, however, instead of merely striving to scale the unstable walls, he ran in a circle, round and round the flashing jaws. As he increased his speed, his centrifugal acceleration, like that of a horse-chestnut which a small boy whirls on a string, gradually forced him outward and upward, thus offsetting to a large extent the sliding action of the sand. But the beast at the bottom, evidently tiring of snapping aimlessly in the air while its prey circled about it and showered it with dirt, began to dig itself out.