The beauty of the world next to come, will be the harmony of double forms, their equilibrium, the gracefulness of their oscillation. From the molluscs even up to man, every being in this next world is to be made up of two corresponding halves; in every animal is to be found (far better than unity) Union.
The master piece of the oursin had gone even beyond what was needed; that miracle of defence had made him prisoner; he was not only shut in but buried; he had dug his own grave. His perfection of isolation had banished him, deprived him of all connections, and of all possibility of progress.
To have a regular ascent, we must commence from a very low stage, from the elementary embryon, which at the outset will have no other movement than that of the elements. The new creature is the mere serf of the planet; so completely so, that even in the egg, it turns as the earth turns, with its double turning on its own axis, and the general rotation.
Even when emancipated from the egg, growing up, become adult, it will still remain the embryon, the soft mollusc. It will vaguely represent the progress of the superior lives; it will be as the fœtus, as the larvæ or nymph of the insect, in which, folded and hidden, there yet are the organs of the winged creature which is yet to come.
One trembles for a creature so weak; even the polypus though not less soft is less in danger. Having life equally in all its parts, wounds, even mutilations will not kill the polypus: wounded and mutilated he still lives on, apparently forgetful of the excised parts. But the centralised mollusc is far more vulnerable. What a door in his ease is open to death!
The uncertain motion of the Medusa, which sometimes, perchance, may save her; the mollusc, at least at the outset, possesses but very slightly. All that is granted to him is his sloughing or exuding a gelatine matter, which walls him in, and replaces the cuirass of the oursin and the oursin's rock. The mollusc has the advantage of finding his defence within himself. Two valves form a house, light and fragile, indeed, so much so that those which float are transparent; in the case of those which are to be stationary, the mucus forms a filamentary anchoring cable, called the hyssas. It is formed exactly as silk is from an element originally quite gelatinous. The gigantic Iridacne, moors so fast by that cable, that the Madrepores mistake it for an islet, build upon it, envelope it, and strangle it.
Passive and motionless life. It has no other event than the periodical visit of the sun and light, and no other action but to absorb what comes, and to secrete the jelly which makes the house, and will by degrees do the rest. The attraction of the light, always in the same direction, centralizes the view; and behold the eye. The secretion fixed by a constant effort, becomes an appendage, an organ which lately was a cable, and which by and bye will become the foot, a shapeless and inarticulated mass, which will bend itself to anything. It is the fin of those that swim, the pick of those that burrow in the sand, and the foot of those who at first rather crawl than walk. Some species arch it so that they can make a clumsy essay at leaping.
Poor tribe, terribly exposed, pursued by many enemies, tossed by the waves and bruised on the rocks. Those of them which do not succeed in building a house, seek a shelter in living beds; they find a tent with the polypes, or with the floating Halcyons. The pearl-bearing Avicule, tries to find a quiet life in the hollows of the sponge. The Pholade, tries in his stony retreat, to imitate the arts of the oursins, but with what inferiority! Instead of the admirable chisel of the oursin, which might be envied by our stone cutters, the Pholade has but a little rasp, and to dig out a shelter for her fragile shell, she wears out the shell itself.
With but a few exceptions, the moluscs know themselves the prey of everything, and are therefore the most timid of creatures. The Cone so well knows that he is sought after, that he dares not leave his shelter, and dies there, from fear of being killed. The Volute and the Porcelain drag slowly along their pretty houses, and conceal them as well as they can. The Casque, to get along with his palace, has only a little Chinese foot, so small and so useless that he scarcely attempts to walk.