With the mutiplicity of apparatus for fish ing, there is the greatest variety in the boats which may be used. The fishing fleet of any part of the world is a most interesting object, as are also the fishermen with their quaint garb, plain speech, and their strange songs and calls with the hauling-in of the net.
Evolution of When a fish dies its body is at once attacked by hundreds of crea tures ranging from the one-celled protozoa and bacteria to individuals of its own species. Its flesh is devoured, the bones are scattered, the gelatinous substance in them decays, and the phosphate of lime is in time dissolved in the water. For this reason few fishes of the mil .
lions that die each year leave any trace for future preservation. At the most, a few teeth, a fin-spine, or a bone buried in the clay might remain intact or in such condition as to be recognized.
But now and then it happens that a dead fish may fall in more fortunate conditions. On a sea-bottom of fine clay the bones, or even the whole body, might be buried in such a way as to be sealed up and protected from total de composition. The fish would in any case dis appear and leave no mark, or at the most a mere cast of its surface. But the hard parts might persist, and now and then they do per sist, the lime unchanged or else silicified or sub jected to some other form of chemical substi tution. Only the scales, the teeth, the bones, the spines and the fin-rays can be preserved in the rocks of sea or lake bottom. In a few localities, as Fossil Station, near Green River, Wyo., Monte Bolca in Tuscany, and Mount Lebanon in Syria, and in lithographic slates in Germany, many skeletons of fishes have been found pressed flat in layers of very fine rock, their structures traced as delicately as if actu ally engraved on the smooth stone. About Ceara in Northern Brazil, many cretaceous fishes have been beautifully preserved in nodules of clay, the eyes and even black spots on the scales being distinctly shown. Fragments pre served in ruder fashion abound in the clays and even the sandstones of the earliest geo logical ages. In most cases, however, fossil fishes are known from detached and scattered fragments, many of them, especially of the sharks, by the teeth alone. Fishes have oc curred in all ages from the Lower Silurian or Ordovician to the present time, and no doubt the very first lived before the Silurian.
No one can say what the earliest fishes were like, nor do we know their real relation to the worms, their presumable ancestors, nor to the tunicates and other chordate forms, not fish like, but still degenerate relatives of the primi tive fish.
From analogy we may suppose that the first fishes which ever were, bore some resemblance to the lancelet, for that is a fish-like creature with every structure reduced to its lowest terms. But as the lancelet has no hard parts, no bones, nor teeth, nor scales, nor fins, no traces of its kind are found among the fossils. If the primi tive fish was like it in important respects, all record of it has necessarily vanished from the earth. It is, however, by no means proved that the ancestral fishes were really soft-bodied or worm-like. Professor Patton of Dartmouth College has shown many reasons for believing that the earliest known types (Ostracophores) were allied to crustaceans, and that from marine forms, ancestors to the modern horse shoe crab (Limulus) and to spiders, the fishes have been derived.
The next group of living fishes the cyclo stomes, including the hagfishes and lampreys, fishes with skull and brain but without limbs or jaws, stands at a great distance above the lancelet in complexity of structure, and equally far from the true fishes in its primitive sim plicity. In fact, the lamprey is farther from the true fish in structure than a perch is from an eagle. Yet for all that, it may be an off shoot from the primitive line of fish-descent. There is not much in the structure of the lamprey which may be preserved in the rocks and no trace of fossil lamprey is actually known to exist.
The oldest unquestioned fragments of fishes have been very lately made known by Charles D. Walcott, from rocks of the Trenton Period in the Ordovician or Lower Silurian. These are from Canon City, Colo. Among these is certainly a small ostracophore (Asterapis desid erata). With it are fragments of a vertebral column, thought doubtfully to belong to an ex tinct type of chimaeras (Dictyorhabdus) and other fragments of bony plates, referred with some doubt to the crossopterygian genus Eripty chius. This renders certain the existence of ostracophores at this early period, and their association with chimaeras and primitive sharks is also possible. These early remains were from shallow, muddy water, more favorable perhaps for ostracophores than for sharks.