Strange monsters are all these deep-sea fish, some of them living as much as 16,000 feet under the surface of the sea, so that if Switzerland were turned upside down in mid-ocean, the peak of Mont Blanc would not reach down to where they swim. Yet they are only modified forms of ordinary fish from the world above, which have become fitted to live under that vast pressure of water. Their skeletons, though bony and well-knit together at that depth, are fibrous and slight compared to those of their surface relations, for although they have to resist a weight of from two to sixteen tons pressing all round them, a ton weight being added for every thousand feet, no special strength is required, because the dense water permeates their whole structure, and the pressures are everywhere equal. It is the same with them as with the most delicate and fragile insects living in our atmosphere, the pressure of which would tear them to pieces if unbalanced by equal pressures within and without. But when these deep-sea fishes are brought up quickly to the surface, the outside pressure no longer balances that inside, and so their tissues loosen and their whole framework starts apart, so that they almost fall to pieces at a touch; and their air-bladder, if they have one, expands so much as to force the stomach out of the mouth, turning them almost inside out. Neither are their lanterns a special creation for their use, but merely adaptations of that slimy fluid which we saw oozing from the scales of the minnow. In some of the deep-sea fish even the outer bones are filled with this fluid, and the line of scales along the side has large openings, so that the body is bathed in glowing slime. In others it collects in glands on the sides, making the phosphorescent spots. In this way the deep-sea fish have become fitted to make a home in the very heart of the ocean. Some with large eyes, seeing by means of their own and their neighbours’ light, others with small eyes and delicate feelers, testing each step as they go, and feeding, probably, on the shower of minute sea-animals that falls continually from above; while some, like the Beryx, the Bombay Duck, and the light-carrying Scopelus, which live nearer the top, come up on still nights to feed at the surface of the sea. [Illustration: Fig. 9. Remoras[27] clinging by their sucking-disk to the under part of a shark.--(_Adapted from Brehm._)]