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Ancient Salamanders

"Slowly moves the march of ages, Slowly grows the forest-king, Slowly to perfection cometh Every great and glorious thing."

ANON.

ONE of the great steps in the upward progress of the animal kingdom was the transition from the fish to the reptile. These two classes are at the present time well marked and clearly separated from each other; but an idea of how the change took place, in the course of Evolution, may be gathered from a study of the important group, or class, which comes in between the two, viz. the amphibians, or batrachia of some naturalists. This important and interesting group forms, as it were, a series of "links" between fishes and reptiles. They derive the latter name from the Greek word batrachos, signifying a frog. But we will speak of them as amphibia, because they live both in water and on land; and during the early part of their lives swim in water like fishes, and moreover breathe as fishes do by means of gills. Afterwards they put away such childish things as gills, and, developing lungs, become air-breathers, and behave like ordinary reptiles.

Modern naturalists who accept the theory of Evolution, as most 1 Greek-amphi, both; and bios, life. do, regard the metamorphosis of the tadpole into a frog as a kind of object-lesson on the part of Dame Nature, given with a view to show us, in a general way and in a short space of time, how the wonderful change from the fish to the reptile took place. By the time the great coal-forests of the Carboniferous period were flourishing, the fish class had attained a high state of development, and were to some extent foreshadowing the amphibian type of creation. Now, we know that when the New Red Sandstone was being laid down, the next great class, viz. the reptiles, had not only made a start, but had struck out in several lines, and were specialised in certain directions, as shown by their bird-like footprints on the Triassic sandstones. Would it not therefore be expected that we should find, in rocks of greater age than the New Red Sandstone, the remains of animals in some respects intermediate between fishes and reptiles? This expectation is fully realised by the presence in such strata (i.e. the coal-measures and Permian rocks) of the remains of quite a large number of amphibia. They also crop up again in the Trias, but after that period are not much in evidence until we come to Tertiary times.

The amphibian class, at the present day, is represented by the frogs, toads, and newts of our own country, and by the salamanders of Japan and the United States. But these are only a meagre remnant of a large number of families that lived ages ago.

Let us endeavour now to take a general view of the amphibian class as it was in the days of long ago, before the creation of man,-to look at their family tree and see what their ancestors were like. When this is done we shall perhaps have a little more respect for the frogs and newts that inhabit our ponds; for they come of a very ancient stock, and one which played an important part in primæval times, branching out here and there into strange and varied forms, as if they could not help themselves. In order to do this we must go a long way back into the world's history; and even then we shall still be some way off the roots of the family tree; or, in other words, we shall be in the dark about the first forms of amphibian life which appeared on the earth's surface.