ON certain large planets, whose climates, owing to the proximity of a violent sun, were very much hotter than our tropics, we sometimes found an intelligent fish-like race. It was bewildering to us to discover that a submarine world could rise to mentality of human rank, and to that drama of the spirit, which we had now so often encountered.

The very shallow and sun-drenched oceans of these great planets provided an immense diversity of habitats and a great wealth of living things. Green vegetation, which could be classified as tropical, subtropical, temperate and arctic, basked on the bright ocean floors. There were submarine prairies and forests. In some regions the giant weeds stretched from the sea-bottom to the waves. In these jungles the blue and blinding light of the sun was reduced almost to darkness. Immense coral-like growths, honeycombed with passages and swarming with all manner of live-things, lifted their spires and turrets to the surface. Innumerable kinds of fish-like creatures of all sizes from sprat to whale inhabited the many levels of the waters, some gliding on the bottom, some daring an occasional leap into the torrid air. In the deepest and darkest regions hosts of sea-monsters, eyeless or luminous, browsed on the ceaseless rain of corpses which sank from the upper levels. Over their deep world lay other worlds of increasing brightness and color, where gaudy populations basked, browsed, stalked, or hunted with arrowy flight. Intelligence in these planets was generally achieved by some unimposing social creature, neither fish nor octopus nor crustacean, but something of all three. It would be equipped with manipulatory tentacles, keen eyes and subtle brain. It would make nests of weed in the crevices of the coral, or build strongholds of coral masonry. In time would appear traps, weapons, tools, submarine agriculture, the blossoming of primitive art, the ritual of primitive religion. Then would follow the typical fluctuating advance of the spirit from barbarism to civilization.

One of these submarine worlds was exceptionally interesting. Early in the life of our galaxy, when few of the stars had yet condensed from the “giant” to the solar type, when very few planetary births had yet occurred, a double star and a single star in a congested cluster did actually approach one another, reach fiery filaments toward one another, and spawn a planet brood. Of these worlds, one, an immense and very aqueous sphere, produced in time a dominant race which was not a single species but an intimate symbiotic partnership of two very alien creatures. The one came of a fish-like stock. The other was in appearance something like a crustacean. In form it was a sort of paddle-footed crab or marine spider. Unlike our crustaceans, it was covered not with a brittle carapace but with a tough pachydermatous hide. In maturity this serviceable jerkin was more or less rigid, save at the joints; but in youth it was very pliant to the still-expanding brain. This creature lived on the coasts and in the coastal waters of the many islands of the planet. Both species were mentally of human rank, though each had specific temperament and ability. In primitive times each had attained by its own route and in its own hemisphere of the great aqueous planet to what might be called the last stage of the subhuman mentality. The two species had then come into contact, and had grappled desperately. Their battle-ground was the shallow coastal water. The “crustaceans,” though crudely amphibian, could not spend long under the sea; the “fish” could not emerge from it. The two races did not seriously compete with one another in economic life, for the “fish” were mainly vegetarian, the “crustaceans” mainly carnivorous; yet neither could tolerate the presence of the other. Both were sufficiently human to be aware of one another as rival aristocrats in a subhuman world, but neither was human enough to realize that for each race the way of life lay in cooperation with the other. The fish-like creatures, which I shall call “ichthyoids,” had speed and range of travel. They had also the security of bulk. The crab-like or spider-like “crustaceans,” which I shall call “arachnoids,” had greater manual dexterity, and had also access to the dry land. Cooperation would have been very beneficial to both species, for one of the staple foods of the arachnoids was parasitic to the ichthyoids.

In spite of the possibility of mutual aid, the two races strove to exterminate one another, and almost succeeded. After an age of blind mutual slaughter, certain of the less pugnacious and more flexible varieties of the two species gradually discovered profit in fraternization with the enemy.

This was the beginning of a very remarkable partnership. Soon the arachnoids took to riding on the backs of the swift ichthyoids, and thus gained access to more remote hunting grounds.

As the epochs passed, the two species molded one another to form a well-integrated union. The little arachnoid, no bigger than a chimpanzee, rode in a snug hollow behind the great “fish’s” skull, his back being stream-lined with the con-tours of the larger creature. The tentacles of the ichthyoid were specialized for large-scale manipulation, those of the arachnoid for minute work. A biochemical interdependence also evolved. Through a membrane in the ichthyoid’s pouch an exchange of endocrine products took place. The mechanism enabled the arachnoid to become fully aquatic. So long as it had frequent contact with its host, it could stay under water for any length of time and descend to any depth. A striking mental adaptation also occurred in the two species. The ichthyoids became on the whole more introvert, the arachnoids more extrovert.

Up to puberty the young of both species were free-living individuals; but, as their symbiotic organization developed, each sought out a partner of the opposite species. The union which followed was life-long, and was interrupted only by brief sexual matings. The symbiosis itself constituted a kind of contrapuntal sexuality; but a sexuality that was purely mental, since, of course, for copulation and reproduction each individual had to seek out a partner belonging to his or her own species. We found, however, that even the symbiotic partnership consisted invariably of a male of one species and a female of the other; and the male, whichever his species, behaved with parental devotion to the young of his symbiotic partner.

I have not space to describe the extraordinary mental reciprocity of these strange couples. I can only say that, though in sensory equipment and in temperament the two species were very different, and though in abnormal cases tragic conflicts did occur, the ordinary partnership was at once more intimate than human marriage and far more enlarging to the individual than any friendship between members of distinct human races. At certain stages of the growth of civilization malicious minds had attempted to arouse widespread interspecific conflict, and had met with temporary success; but the trouble seldom went as deep even as our “sex war,” so necessary was each species to the other. Both had contributed equally to the culture of their world, though not equally at all times. In creative work of every kind one of the partners provided most of the originality, the other most of the criticism and restraint. Work in which one partner was entirely passive was rare. Books, or rather scrolls, which were made from pulped seaweed, were nearly always signed by couples. On the whole the arachnoid partners dominated in manual skill, experimental science, the plastic arts, and practical social organization. The ichthyoid partners excelled in theoretical work, in literary arts, in the surprisingly developed music of that submarine world, and in the more mystical kind of religion. This generalization, however, should not be interpreted very strictly.

The symbiotic relationship seems to have given the dual race a far greater mental flexibility than ours, and a quicker aptitude for community. It passed rapidly through the phase of inter-tribal strife, during which the nomadic shoals of symbiotic couples harried one another like hosts of submarine-cavalry; for the arachnoids, riding their ichthyoid mates, attacked the enemy with bone spears and swords, while their mounts wrestled with powerful tentacles. But the phase of tribal warfare was remarkably brief. When a settled mode of life was attained, along with submarine agriculture and coral-built cities, strife between leagues of cities was the exception, not the rule. Aided no doubt by its great mobility and ease of communication, the dual race soon built up a world-wide and unarmed federation of cities. We learned also with wonder that at the height of the pre-mechanical civilization of this planet, when in our worlds the cleavage into masters and economic slaves would already have become serious, the communal spirit of the city triumphed over all individualistic enterprise. Very soon this world became a tissue of interdependent but independent municipal communes.

At this time it seemed that social strife had vanished forever. But the most serious crisis of the race was still to come.

The submarine environment offered the symbiotic race no great possibilities of advancement. All sources of wealth had been tapped and regularized. Population was maintained at an optimum size for the joyful working of the world. The social order was satisfactory to all classes, and seemed unlikely to change. Individual lives were full and varied. Culture, founded on a great tradition, was now concerned entirely with detailed exploration of the great fields of thought that had long ago been pioneered by the revered ancestors, under direct inspiration, it was said, of the symbiotic diety. Our friends in this submarine world, our mental hosts, looked back on this age from their own more turbulent epoch sometimes with yearning, but often with horror; for in retrospect it seemed to them to display the first faint signs of racial decay. So perfectly did the race fit its unchanging environment that intelligence and acuity were already ceasing to be precious, and might soon begin to fade. But presently it appeared that fate had decreed otherwise.

In a submarine world the possibility of obtaining mechanical power was remote. But the arachnoids, it will be remembered, were able to live out of the water. In the epochs before the symbiosis their ancestors had periodically emerged upon the islands, for courtship, parenthood, and the pursuit of prey. Since those days the air-breathing capacity had declined, but it had never been entirely lost. Every arachnoid still emerged for sexual mating, and also for certain ritual gymnastic exercises. It was in this latter connection that the great discovery was made which changed the course of history. At a certain tournament the friction of stone weapons, clashing against one another, produced sparks, and fire among the sun-scorched grasses.

In startlingly quick succession came smelting, the steam engine, the electric current. Power was obtained first from the combustion of a sort of peat formed on the coasts by congested marine vegetation, later from the constant and violent winds, later still from photo-chemical light traps which absorbed the sun’s lavish radiation. These inventions were of course the work of arachnoids. The ichthyoids, though they still played a great part in the systematization of knowledge, were debarred from the great practical work of scientific experiment and mechanical invention above the seas. Soon the arachnoids were running electric cables from the island power-stations to the submarine cities. In this work, at least, the ichthyoids could take part, but their part was necessarily subordinate. Not only in experience of electrical engineering but also in native practical ability they were eclipsed by their arachnoid partners.

For a couple of centuries or more the two species continued to cooperate, though with increasing strain. Artificial lighting, mechanical transport of goods on the ocean floor, and large-scale manufacture, produced an immense increase in the amenities of life in the submarine cities. The islands were crowded with buildings devoted to science and industry. Physics, chemistry, and biology made great progress. Astronomers began to map the galaxy. They also discovered that a neighboring planet offered wonderful opportunities for settlement by arachnoids, who might without great difficulty, it was hoped, be conditioned to the alien climate, and to divorce from their symbiotic partners. The first attempts at rocket flight were leading to mingled tragedy and success. The directorate of extra-marine activities demanded a much increased arachnoid population.

Inevitably there arose a conflict between the two species, and in the mind of every individual of either species. It was at the height of this conflict, and in the spiritual crisis in virtue of which these beings were accessible to us in our novitiate stage, that we first entered this world. The ichthyoids had not yet succumbed biologically to their inferior position, but psychologically they were already showing signs of deep mental decay. A profound disheartenment and lassitude attacked them, like that which so often undermines our primitive races when they find themselves struggling in the flood of European civilization. But since in the case of the symbiotics the relation between the two races was extremely intimate, far more so than that between the most intimate human beings, the plight of the ichthyoids deeply affected the arachnoids. And in the minds of the ichthyoids the triumph of their partners was for long a source of mingled distress and exultation. Every individual of both species was torn between conflicting motives. While every healthy arachnoid longed to take part in the adventurous new life, he or she longed also, through sheer affection and symbiotic entanglement, to assist his or her ichthyoid mate to have an equal share in that life. Further, all arachnoids were aware of subtle dependence on their mates, a dependence at once physiological and psychological. It was the ichthyoids who mostly contributed to the mental symbiosis the power of self-knowledge and mutual insight, and the contemplation which is so necessary to keep action sweet and sane. That this was so was evident from the fact that already among the arachnoids internecine strife had appeared. Island tended to compete with island, and one great industrial organization with another.

I could not help remarking that if this deep cleavage of interests had occurred on my own planet, say between our two sexes, the favoured sex would have single-mindedly trampled the other into servitude. Such a “victory” on the part of the arachnoids did indeed nearly occur. More and more partnerships were dissolved, each member attempting by means of drugs to supply his or her system with the chemicals normally provided by the symbiosis. For mental dependence, however, there was no substitute, and the divorced partners were subject to serious mental disorders, either subtle or flagrant. Nevertheless, there grew up a large population capable of living after a fashion without the symbiotic intercourse. Strife now took a violent turn. The intransigents of both species attacked one another, and stirred up trouble among the moderates. There followed a period of desperate and confused warfare. On each side a small and hated minority advocated a “modernized symbiosis,” in which each species should be able to contribute to the common life even in a mechanized civilization. Many of these reformers were martyred for their faith.

Victory would in the long run have gone to the arachnoids, for they controlled the sources of power. But it soon appeared that the attempt to break the symbiotic bond was not as successful as it had seemed. Even in actual warfare, commanders were unable to prevent widespread fraternization between the opposed forces. Members of dissolved partnerships would furtively meet to snatch a few hours or moments of each other’s company. Widowed or deserted individuals of each species would timidly but hungrily venture toward the enemy’s camps in search of new mates. Whole companies would surrender for the same purpose. The arachnoids suffered more from the neuroses than from the weapons of the enemy. On the islands, moreover, civil wars and social revolutions made the manufacture of munitions almost impossible.

The most resolute faction of the arachnoids now attempted to bring the struggle to an end by poisoning the ocean. The islands in turn were poisoned by the millions of decaying corpses that rose to the sea’s surface and were cast up on the shores. Poison, plague, and above all neurosis, brought war to a standstill, civilization to ruin, and the two species almost to extinction. The deserted sky-scrapers that crowded the islands began to crumble into heaps of wreckage. The submarine cities were invaded by the submarine jungle and by shark-like sub-human ichthyoids of many species. The delicate tissue of knowledge began to disintegrate into fragments of superstition.

Now at last came the opportunity of those who advocated a modernized symbiosis. With difficulty they had maintained a secret existence and their individual partnerships in the more remote and inhospitable regions of the planet. They now came boldly forth to spread their gospel among the unhappy remnants of the world’s population. There was a rage of interspecific mating and remating. Primitive submarine agriculture and hunting maintained the scattered peoples while a few of the coral cities were cleared and rebuilt, and the instruments of a lean but hopeful civilization were refashioned. This was a temporary civilization, without mechanical power, but one which promised itself great adventures in the “upper world” as soon as it had established the basic principles of the reformed symbiosis.

To us it seemed that such an enterprise was doomed to failure, so clear was it that the future lay with a terrestrial rather than a marine creature. But we were mistaken. I must not tell in detail of the heroic struggle by which the race refashioned its symbiotic nature to suit the career that lay before it. The first stage was the reinstatement of power stations on the islands, and the careful reorganization of a purely submarine society equipped with power. But this reconstruction would have been useless had it not been accompanied by a very careful study of the physical and mental relations of the two species. The symbiosis had to be strengthened so that interspecific strife should in future be impossible. By means of chemical treatment in infancy the two kinds of organism were made more interdependent, and in partnership more hardy. By a special psychological ritual, a sort of mutual hypnosis, all newly joined partners were henceforth brought into indissoluble mental reciprocity. This interspecific communion, which every individual knew in immediate domestic experience, became in time the basic experience of all culture and religion. The symbiotic deity, which figured in all the primitive mythologies, was reinstated as a symbol of the dual personality of the universe, a dualism, it was said, of creativity and wisdom, unified as the divine spirit of love. The one reasonable goal of social life was affirmed to be the creation of a world of awakened, of sensitive, intelligent, and mutually understanding personalities, banded together for the common purpose of exploring the universe and developing the “human” spirit’s manifold potentialities. Imperceptibly the young were led to discover for themselves this goal.

Gradually and very cautiously all the industrial operations and scientific researches of an earlier age were repeated, but with a difference. Industry was subordinated to the conscious social goal. Science, formerly the slave of industry, became the free colleague of wisdom.

Once more the islands were crowded with buildings and with eager arachnoid workers. But all the shallow coastal waters were filled with a vast honeycomb of dwelling-houses, where the symbiotic partners took rest and refreshment with their mates. In the ocean depths the old cities were turned into schools, universities, museums, temples, palaces of art and of pleasure. There the young of both kinds grew up together. There the full-grown of both species met constantly for recreation and stimulation. There, while the arachnoids were busy on the islands, the ichthyoids performed their work of education and of refashioning the whole theoretical culture of the world. For it was known clearly by now that in this field their temperament and talents could make a vital contribution to the common life. Thus literature, philosophy, and non-scientific education were carried out chiefly in the ocean; while on the islands industry, scientific inquiry, and the plastic arts were more prominent.

Perhaps, in spite of the close union of each couple, this strange division of labor would have led in time to renewed conflict, had it not been for two new discoveries. One was the development of telepathy. Several centuries after the Age of War it was found possible to establish full telepathic intercourse between the two members of each couple. In time this intercourse was extended to include the whole dual race. The first result of this change was a great increase in the facility of communication between individuals all over the world, and therewith a great increase in mutual understanding and in unity of social purpose. But before we lost touch with this rapidly advancing race we had evidence of a much more far-reaching effect of universal telepathy. Sometimes, so we were told, telepathic communion of the whole race caused something like the fragmentary awakening of a communal world-mind in which all individuals participated.

The second great innovation of the race was due to genetic research. The arachnoids, who had to remain capable of active life on dry land and on a massive planet, could not achieve any great improvement in brain weight and complexity; but the ichthyoids, who were already large and were buoyed up by the water, were not subject to this limitation. After long and often disastrous experiment a race of “super-ichthyoids” was produced. In time the whole ichthyoid population came to consist of these creatures. Meanwhile the arachnoids, who were by now exploring and colonizing other planets of their solar system, were genetically improved not in respect of general brain complexity but in those special brain centers which afforded telepathic intercourse. Thus, in spite of their simpler brain-structure, they were able to maintain full telepathic community even with their big-brained mates far away in the oceans of the mother-planet. The simple brains and the complex brains formed now a single system, in which each unit, however simple its own contribution, was sensitive to the whole.

It was at this point, when the original ichthyoid race had given place to the super-ichthyoids, that we finally lost touch. The experience of the dual race passed completely beyond our comprehension. At a much later stage of our adventure we came upon them again, and on a higher plane of being. They were by then already engaged upon the vast common enterprise which, as I shall tell, was undertaken by the Galactic Society of Worlds. At this time the symbiotic race consisted of an immense host of arachnoid adventurers scattered over many planets, and a company of some fifty thousand million super-ichthyoids living a life of natatory delight and intense mental activity in the ocean of their great native world. Even at this stage physical contact between the symbiotic partners had to be maintained, though at long intervals. There was a constant stream of space-ships between the colonies and the mother-world. The ichthyoids, together with their teeming colleagues on a score of planets, supported a racial mind. Though the threads of the common experience were spun by the whole symbiotic race, they were woven into a single web by the ichthyoids alone in their primeval oceanic home, to be shared by all members of both races.