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. Such the life, such the dwelling; in no other species is there more complete identity between the inhabitant and the habitation; taken from his own substance, his house is but a continuation, a supplement of his own body; alike it even in form and tints. The architect, beneath the edifice, is himself its very foundation-stone. A very simple thing it is for the sedentaries to remain sedentary. The oyster, regularly fed by the sea, has only to gape when he would dine, and sharply to close his shells, when he has any suspicion that he may become himself a dinner for some hungry neighbor. But for the travelling mollusc the thing is more complicated. He can travel, but he cannot leave behind him his beloved house which he will need for defence as well as shelter; and it is precisely while on his journey, that he is most liable to be attacked. He must shelter, above all, the most delicate part of his being, the tree by which he breathes, and whose little roots nourish him. His head is of little consequence, often it is lost without the destruction of life; but if the viscera were left uncovered and wounded, he must die. Thus, prudent and cuirassed he seeks his livelihood. Come nightfall, he asks himself whether he will be quite safe in a wide open lodging? Will not some inquisitives intrude a look--who knows--may not some one find the way in with claw and tooth as well as glance?