they were as high in the order of creation as the commonest lobster of the sea-shore. Nothing remains to us of them except their bony structure, but we believe that they could both swim and walk on the sea-bottom; that some were swift of movement, and that they acquired the habit of moulting their shell. They may have been sociable animals, for the shells of trilobites are sometimes found together in large numbers, occasionally closely packed, "spoon fashion," and though these may be moulted shells, we are warranted in supposing that the early trilobites lived in colonies, hunted for food, and made war like their descendants millions of years after. What were the actual conditions of life in this world of Cambrian days we do not know positively. The first beginnings of life, the simple one-celled plants, may have first dwelt in the deep ocean. The land was barren, its lakes unfitted to support life. On the other hand, it is equally likely that the first beginnings of life may have been the simple plants growing in inland waters and gradually spreading down to the sea. We do not know, but it is most probable that life began in some great body of water, where plants and insignificant animals grew together, perhaps fought together, and certainly in this environment became more and more fitted for the business of living. In Mr. Henry R. Knipe's scholarly and well-informed volume, _Nebula to Man_ (J. M. Dent & Co.), to which we are indebted not only for several of our illustrations but for many extremely valuable suggestions, the struggle for existence in the early ocean is well summed up:-- Thus through the brine life manifold proceeds, Impelled to higher states by growing needs; And all these early life-types in the seas Will branch in time to many species; And some amid conditions too severe, Must, after stress and struggle, disappear. And when a species falls from Life's domain It never gains a place on Earth again. We may speculate with some approach to certainty on the general appearance of the earth in those days. There was far more water on the surface of the globe; the land surfaces were small and infrequent. The seas may have been shallower than those which we know, but they were far greater in extent. There must have been far more rain and a very much greater number of violent storms arising from the constant condensation of the waters by the rays of the sun. The sun was probably seen far less often in those days, and there are some geologists who believe the earth to have been perpetually covered with cloud, as the planet Venus is now.