They were highly satisfactory, from a technical point of view. Now there was soil which swarmed with minute living things. There were fungi which throve monstrously. The seas stank of minuscule life-forms. There were even some novelties, developed by the strictly local conditions. There were, for example, paramoecia as big as grapes, and yeasts had increased in size until they bore flowers visible to the naked eye. The life on the planet was not aboriginal, though. All of it was descended and adapted and modified from the microörganisms planted by the seed-ship whose hulk was long since rust, and whose crew were merely names in genealogies--if that. The _Ludred_ stayed on the planet a considerably longer time than either of the ships that had visited it before. It dropped the seeds of plants. It broadcast innumerable varieties of things which should take root and grow. In some places it deliberately seeded the stinking soil. It put marine plants in the oceans. It put alpine plants on the high ground. And when all its stable varieties were set out it added plants which were genetically unstable. For generations to come they would throw sports, some of which should be especially suited to this planetary environment. Before it left, the _Ludred_ dumped finny fish into the seas. At first they would live on the plankton which made the oceans almost broth. There were many varieties of fish. Some would multiply swiftly while small; others would grow and feed on the smaller varieties. And as a last activity, the _Ludred_ set up refrigeration-units loaded with insect-eggs. Some would release their contents as soon as plants had grown enough to furnish them with food. Others would allow their contents to hatch only after certain other varieties had multiplied--to be their food-supply. When the Ecology-Ship left, it had done a very painstaking job. It had treated the planet to a sort of Russell's Mixture of life-forms. The real Russell's Mixture is that blend of the simple elements in the proportions found in suns. This was a blend of life-forms in which some should survive by consuming the now-habituated flora, others by preying on the former. The planet was stocked, in effect, with everything that it could be hoped would live there. But only certain things could have that hope. Nothing which needed parental care had any chance of survival. The creatures seeded at this time had to be those which could care for themselves from the instant they burst their eggs. So there were no birds or mammals. Trees and plants of many kinds, fish and crustaceans and tadpoles, and all kinds of insects could be planted. But nothing else. The _Ludred_ swam away through emptiness.