A world abundantly peopled. A world which holds its myriads, uncountable in kinds, beyond reckoning in numbers. No part of the wide Ocean may be found where fishes are not, and in places, at seasons, the water positively teems with them, so that they may be said almost to hustle one another for want of space. Fishes, taken by themselves, letting alone jelly-inhabitants and shell-inhabitants and crab-inhabitants, would suffice to keep the whole sea alive. No picture of the Great Deep would be, even in the humblest sense, complete without some little description of the world of Fish-life contained therein. But the subject is one of hopeless magnitude to be dealt with in a couple of short chapters. A mere list of the names and chief characteristics of the principal “Orders” of Fishes, putting on one side the immense array of “sub-orders” and “varieties,” would speedily outrun the limits of these pages. Besides, such a list would be to the ordinary reader unreadable. Natural History _savants_ have not troubled themselves to curtail syllables in titles so used. On land we have beasts and birds, which serve as food for man; beasts and birds of prey; beasts and birds that are simply harmless, attractive, pretty, or interesting. In the Ocean also we find fishes good for food; fishes of prey; fishes which may be classed as merely pretty, or curious, or remarkable. This rough classification will do well enough for our present purpose. Many fishes belong of course to more than one of the divisions. That which is good for food may be also curious. That which acts as an ocean “beast of prey” may be also beautiful. The speed with which fishes can dart along is often very great. Both fins and tails are used as a means of advance; and the smooth scale-clothed skin glides with the least possible friction through the water. No better form than the “boat-shaped” outline could be devised for rapid progress in a heavy element. Not only are fishes light in make, often weighing hardly more than the water which upholds them; but also, unlike most backboned animals, they are cold-blooded. A few deep-sea kinds have no eyes, though commonly they can see and hear and smell well. In the sense of feeling they are believed to be very deficient, and it is doubtful whether they suffer any pain at all, in the true sense of the word. Probably they can be conscious of discomfort. One of their unfailing characteristics is the possession of a stupendous appetite, and with it of a superlatively good digestion. They live to eat; and they are at it incessantly. Perhaps in their case it does not always mean greediness, but only a due satisfying of Nature’s needs.