The Book of Household Management by Mrs. Beeton

Linnaeus, and are described as having long under-jaws, eggs without white, organs of sense, fins for supporters, bodies covered with concave scales, gills to supply the place of lungs for respiration, and water for the natural element of their existence. Had mankind no other knowledge of animals than of such as inhabit the land and breathe their own atmosphere, they would listen with incredulous wonder, if told that there were other kinds of beings which existed only in the waters, and which would die almost as soon as they were taken from them. However strongly these facts might be attested, they would hardly believe them, without the operation of their own senses, as they would recollect the effect produced on their own bodies when immersed in water, and the impossibility of their sustaining life in it for any lengthened period of time. Experience, however, has taught them, that the "great deep" is crowded with inhabitants of various sizes, and of vastly different constructions, with modes of life entirely distinct from those which belong to the animals of the land, and with peculiarities of design, equally wonderful with those of any other works which have come from the hand of the Creator. The history of these races, however, must remain for ever, more or less, in a state of darkness, since the depths in which they live, are beyond the power of human exploration, and since the illimitable expansion of their domain places them almost entirely out of the reach of human accessibility.