There is also a certain curious tropical American carp which, though it hardly deserves to be considered in the strictest sense as a fish out of water, yet manages to fall nearly half-way under that peculiar category, for it always swims with its head partly above the surface and partly below.  But the funniest thing in this queer arrangement is the fact that one half of each eye is out in the air and the other half is beneath in the water.  Accordingly, the eye is divided horizontally by a dark strip into two distinct and unlike portions, the upper one of which has a pupil adapted to vision in the air alone, while the lower is adapted to seeing in the water only.  The fish, in fact, always swims with its eye half out of the water, and it can see as well on dry land as in its native ocean.  Its name is Anableps, but in all probability it does not wish the fact to be generally known.

The flying fish are fish out of water in a somewhat different and more transitory sense.  Their aerial excursions are brief and rapid; they can only fly a very little way, and have soon to take once more for safety to their own more natural and permanent element.  More than forty kinds of the family are known, in appearance very much like English herrings, but with the front fins expanded and modified into veritable wings.  It is fashionable nowadays among naturalists to assert that the flying fish don’t fly; that they merely jump horizontally out of the water with a powerful impulse, and fall again as soon as the force of the first impetus is entirely spent.  When men endeavour to persuade you to such folly, believe them not.  For my own part, I have seen the flying fish fly—­deliberately fly, and flutter, and rise again, and change the direction of their flight in mid-air, exactly after the fashion of a big dragonfly.  If the other people who have watched them haven’t succeeded in seeing them fly, that is their own fault, or at least their own misfortune; perhaps their eyes weren’t quick enough to catch the rapid, though to me perfectly recognisable, hovering and fluttering of the gauze-like wings; but I have seen them myself, and I maintain that on such a question one piece of positive evidence is a great deal better than a hundred negative.  The testimony of all the witnesses who didn’t see the murder committed is as nothing compared with the single testimony of the one man who really did see it.  And in this case I have met with many other quick observers who fully agreed with me, against the weight of scientific opinion, that they have seen the flying fish really fly with their own eyes, and no mistake about it.  The German professors, indeed, all think otherwise; but then the German professors all wear green spectacles, which are the outward and visible sign of ‘blinded eyesight poring over miserable books.’  The unsophisticated vision of the noble British seaman is unanimously with me on the matter of the reality of the fishes’ flight.