It was in desperate haste that the last Venerian men had designed and fashioned the new species for the colonization of Neptune. The mere remoteness of the great planet, moreover, had prevented its nature from being explored at all thoroughly, and so the new human organism was but partially adapted to its destined environment. Inevitably it was a dwarf type, limited in size by the necessity of resisting an excessive gravitation. Its brain was so cramped that everything but the bare essentials of humanity had to be omitted from it. Even so, the Ninth Men were too delicately organized to withstand the ferocity of natural forces on Neptune. This ferocity the designers had seriously underestimated; and so they were content merely to produce a miniature copy of their own type. They should have planned a hardy brute, lustily procreative, cunning in the struggle for physical existence, but above all tough, prolific, and so insensitive as to be scarcely worthy of the name man. They should have trusted that if once this crude seed could take root, natural forces themselves would in time conjure from it something more human. Instead, they produced a race cursed with the inevitable fragility of miniatures, and designed for a civilized environment which feeble spirits could not possibly maintain in a tumultuous world. For it so happened that the still youthful giant, Neptune, was slowly entering one of his phases of crustal shrinkage, and therefore of earthquake and eruption. Thus the frail colonists found themselves increasingly in danger of being swallowed in sudden fiery crevasses or buried under volcanic dust. Moreover, their squat buildings, when not actually being trampled by lava streams, or warped and cracked by their shifting foundations, were liable to be demolished by the battering-ram thrust of a turbulent and massive atmosphere. Further, the atmosphere’s unwholesome composition killed all possibility of cheerfulness and courage in a race whose nature was doomed to be, even in favourable circumstances, neurotic.

Fortunately this agony could not last indefinitely. Little by little, civilization crumbled into savagery, the torturing vision of better things was lost, man’s consciousness was narrowed and coarsened into brute-consciousness. By good luck the brute precariously survived.

Long after the Ninth Men had fallen from man’s estate, nature herself, in her own slow and blundering manner, succeeded where man had failed. The brute descendants of this human species became at length well adapted to their world. In time there arose a wealth of subhuman forms in the many kinds of environment afforded by the lands and seas of Neptune. None of them penetrated far towards the Equator, for the swollen sun had rendered the tropics at this time far too hot to support life of any kind. Even at the pole the protracted summer put a great strain on all but the most hardy creatures.

Neptune’s year was at this time about one hundred and sixty-five times the length of the old terrestrial year. The slow seasonal change had an important effect on life’s own rhythms. All but the most ephemeral organisms tended to live through at least one complete year, and the higher mammals survived longer. At a much later stage this natural longevity was to play a great and beneficial part in the revival of man. But, on the other hand, the increasing sluggishness of individual growth, the length of immaturity in each generation, retarded the natural evolutionary process on Neptune, so that compared with the Terrestrial and Venerian epochs the biological story now moves at a snail’s pace.

After the fall of the Ninth Men the subhuman creatures had one and all adopted a quadruped habit, the better to cope with gravity. At first they had indulged merely in occasional support from their knuckles, but in time many species of true quadrupeds had appeared. In several of the running types the fingers, like the toes, had grown together, and a hoof had developed, not on the old finger-tips, which were bent back and atrophied, but on the knuckles.

Two hundred millions years after the solar collision innumerable species of subhuman grazers with long sheep-like muzzles, ample molars, and almost ruminant digestive systems, were competing with one another on the polar continent. Upon these preyed the subhuman carnivora, of whom some were built for speed in the chase, others for stalking and a sudden spring. But since jumping was no easy matter on Neptune, the cat-like types were all minute. They preyed upon man’s more rabbit-like and rat-like descendants, or on the carrion of the larger mammals, or on the lusty worms and beetles. These had sprung originally from vermin which had been transported accidentally from Venus. For of all the ancient Venerian fauna only man himself, a few insects and other invertebrates, and many kinds of micro-organisms, succeeded in colonizing Neptune. Of plants, many types had been artificially bred for the new world, and from these eventually arose a host of grasses, flowering plants, thick-trunked bushes, and novel sea-weeds. On this marine flora fed certain highly developed marine worms; and of these last, some in time became vertebrate, predatory, swift, and fish-like. On these in turn man’s own marine descendants preyed, whether as subhuman seals, or still more specialized subhuman porpoises. Perhaps most remarkable of these developments of the ancient human stock was that which led, through a small insectivorous bat-like glider, to a great diversity of true flying mammals, scarcely larger than humming birds, but in some cases agile as swallows.

Nowhere did the typical human form survive. There were only beasts, fitted by structure and instinct to some niche or other of their infinitely diverse and roomy world.

Certain strange vestiges of human mentality did indeed persist here and there, even as, in the fore-limbs of most species, there still remained buried the relics of man’s once cunning fingers. For instance, there were certain grazers which in times of hardship would meet together and give tongue in cacophonous ululation; or, sitting on their haunches with fore-limbs pressed together, they would listen by the hour to the howls of some leader, responding intermittently with groans and whimpers, and working themselves at last into foaming madness. And there were carnivora which, in the midst of the spring-time fervour, would suddenly cease from love-making, fighting, and the daily routine of hunting, to sit alone in some high place day after day, night after night, watching, waiting; until at last hunger forced them into action.

Now in the fullness of time, about three hundred million terrestrial years after the solar collision, a certain minute, hairless, rabbit-like creature, scampering on the polar grasslands, found itself greatly persecuted by a swift hound from the south. The subhuman rabbit was relatively unspecialized, and had no effective means of defence or flight. It was almost exterminated. A few individuals, however, saved themselves by taking to the dense and thick-trunked scrub, whither the hound could not follow them. Here they had to change their diet and manner of life, deserting grass for roots, berries, and even worms and beetles. Their fore-limbs were now increasingly used for digging and climbing, and eventually for weaving nests of stick and straw. In this species the fingers had never grown together. Internally the fore-paw was like a minute clenched fist from the elongated and exposed knuckles of which separate toes protruded. And now the knuckles elongated themselves still further, becoming in time a new set of fingers. Within the palm of the new little monkey-hand there still remained traces of man’s ancient fingers, bent in upon themselves.

As of old, manipulation gave rise to clearer percipience. And this, in conjunction with the necessity of frequent experiments in diet, hunting, and defence, produced at length a real versatility of behaviour and suppleness of mind. The rabbit throve, adopted an almost upright gait, continued to increase in stature and in brain. Yet, just as the new hand was not merely a resurrection of the old hand, so the new regions of the brain were no mere revival of the atrophied human cerebrum, but a new organ, which overlaid and swallowed up that ancient relic. The creature’s mind, therefore, was in many respects a new mind, though moulded to the same great basic needs. Like his forerunners, of course, he craved food, love, glory, companionship. In pursuit of these ends he devised weapons and traps, and built wicker villages. He held pow-wows. He became the Tenth Men.