Page:Popular Science Monthly Volume 29.djvu/118

108 and a vagabond on the face of the waters, leading what the scientific men prettily describe as a pelagic existence, and much more frequently met with in the open sea than among the shallows and sand-banks which are to form the refuge of his maturer years. But soon his Wanderjähre are fairly over: the transparency of early youth fades out with him exactly as it fades out in the human subject: he begins to seek the recesses of the sea, settles down quietly in a comfortable hollow, and gives up his youthful Bohemian aspirations in favor of safety and respectability on a sandy bottom. This, of course, is all as it should be; in thus sacrificing freedom to the necessities of existence he only follows the universal rule of animated nature. But, like all the rest of us when we settle down into our final groove, he shortly begins to develop a tendency toward distinct one-sidedness. Lying flat on the sand upon his left cheek and side, he quickly undergoes a strange metamorphosis from the perfect and symmetrical to the lopsided condition. His left eye, having now nothing in particular to look at on the sands below, takes naturally to squinting as hard as it can round the corner, to observe the world above it; and so effectually does it manage to squint that it at last pulls all the socket and surrounding parts clean round the head to the right or upper surface. In short, the young sole lies on his left side till that half of his face (except the mouth) is compelled to twist itself round to the opposite cheek, thus giving him through life the appearance constantly deprecated by nurses who meet all unilateral grimaces on the part of their charges with the awful suggestion, "Suppose you were to be struck so!" The young sole is actually struck so, and remains in that distressing condition ever afterward.

This singular early history of the individual sole evidently recapitulates for us in brief the evolutionary history of the entire group to which he belongs. It is pretty clear (to believers, at least) that the prime ancestor of all the flat-fish was a sort of cod, and that his descendants only acquired their existing flatness by long persistence in the pernicious habit of lying always entirely on one side. Why the primeval flat-fish first took to this queer custom is equally easy to understand. Soles, turbots, plaice, brill, and other members of the flatfish family are all, as we well know, very excellent edible fishes. Their edibility is as highly appreciated by the sharks and dog-fish as by the enlightened public of a Christian land. Moreover, they are ill-provided with any external protection, having neither fierce jaws, like the pike and shark; efficient weapons of attack, like the sword-fish and the electric eel; or stout defensive armor, like the globe-fish, the file-fish, and the bony pike, whose outer covering is as effectually repellent as that of a tortoise, an armadillo, or a hedgehog. The connection between these apparently dissimilar facts is by no means an artificial one. Fish which possess one form of protection seldom require the additional aid of another: for example, all the electric fish have scaleless bodies,