"Scores! There is the fabled unicorn ... a one-horned gazelle-like animal certainly not indigenous to Terra, yet it found its place in the 'unnatural natural history' of not one but a dozen races. Whence originated this record of a single horned creature we could not guess .. until we discovered such a beast on Venus. "The fabulous 'salamander' turned out to be a common asbestos-like lizard of Mercury. Aqueous Venus solved for us the problems of the mermaid, the sea serpent and the undine. On mighty Jupiter mythologists encountered the fire-breathing saurian which gave rise to the 'dragon' myth--" "But, Doctor Roswell!" gasped the girl, "what does this mean? That once upon a time, countless centuries ago, beasts of this sort roamed Earth? Or--?" Rocky shook his head soberly. "We do not know, Miss Graham. There are a number of equally valid possibilities. One is that which you have mentioned ... that Earth was once host to all the types of animal life now to be found on its sister planets. Another is that aeons ago Earthmen--or the intellectual rulers of one of the other planets--knew the secret of spacetravel. The factual records of places visited, strange sights seen, would in the musty passage of time become mythology. "Still another possibility--" "Yes?" "Well, it is ... er ... a theory recently advanced by an erudite scholar, but it has elements of fantasy which make it almost incredible. You are ... er ... familiar with the theories of Svante Arrhenius?" Lynn frowned. "I remember the name faintly. Didn't he claim life traveled through the ether?" "Yes. He put forward, the concept that the life-germ is universally diffused, constantly emitted from all habitable worlds in the form of spores which traverse space for years or ages, the majority being ultimately destroyed by the flame of some blazing star, but some few finding a resting-place on bodies which have reached the habitable stage. "My colleague has carried this theory a step forward, suggesting it is not only the fundamental life-germ which thus travels ... but also individual and distinctive life-forms! He has suggested that from each and every world in every galaxy, occasionally there set forth into the void the spores or eggs of every highly developed life-form. "Most of these never reach their destinations. Some do. And when these do, unwilling worlds play host to beasts of nightmare mien." IV A babble from the street lifted Humboldt Grossman's eyes from shrewd perusal of his ledgers. He frowned, rose to investigate the tumult, then stood stock-still in his tracks, startled as the door of his private chamber burst open. A stunted troll with four, gnarled, dangling arms--a native Titanian--served as spokesman for the excited group.