A yowl now came from the farther peak, and the old leader paused abruptly in his conversation. It was one of the army's outposts, stationed on the highest of the mountains to watch the one foe which Earth's cats fear; the very large and peculiar cats from Saturn, who for some reason have not been oblivious of the charm of our moon's dark side. They are leagued by treaty with the evil toad-things, and are notoriously hostile to our earthly cats; so that at this juncture a meeting would have been a somewhat grave matter.