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The uppermost flower in general bears ten stamens, whilst the next boasts of but eight each. Its capsules are two-beaked, one-celled, and two-valved, the seeds numerous and roundish. It is named from chrysos, 'gold, and splen, 'the spleen. There is another specimen much like this, of which I have spoken, Chrysosplenium alternitifolium; but it is larger, handsomer, and less common.
Like all creatures with oxygen-and-water based metabolisms, the Moruans could trace their evolutionary line to minute one-celled salt-water creatures; but with the bitter cold of the planet, the first land-creatures to emerge from the primeval swamp of Morua VIII had developed the heavy furs and the hibernation characteristics of bear-like mammals.
In like manner, in spite of the complicated apparatus which supplies oxygen and removes carbon dioxide, the respiratory system, respiration is finally the work of the cell, as in amoeba; a muscle-cell respires exactly as does the one-celled animal.
The Thalamophores, the sister-group of one-celled animals which largely compose our chalk and much of our limestone, are developed on the same principle. The earlier forms seem to have lived in a part of the ocean where silica was scarce, and they absorbed and built their protective frames of lime. In the simpler types the frame is not unlike a wide-necked bottle, turned upside-down.
The evolution of the wonderfully varied societies found among insects begins with the solitary insect itself, just as this, viewed as a cell-community, originates from one-celled beginnings like Amoeba through progressive evolution in time.
"The larger fleas have smaller fleas Upon their backs to bite um, These little fleas still smaller fleas And so ad infinitum." Coming now to the minute, microscopic, one-celled animals, the Protozoa, we find entire groups of them that are living parasitic lives, depending wholly on one or more hosts for their existence.
But in the case of a close relative of the ameba, the one-celled animal known as the paramecium, union with another paramecium, true conjugation, has been proved necessary to prevent death sooner or later.
The Sponges are a side-issue, or cul de sac, from the Protozoic world, and do not lead on to the higher. Each one-celled unit remains an animal; it is a colony of unicellulars, not a many-celled body. We may admire it as an instructive approach toward the formation of a many-celled body, but we must look elsewhere for the true upward advance.
But for all organic bodies, from the amoeba which is a simple and for the most part unprotected piece of albumen with a cell centre in the midst to man, and from the smallest one-celled desmidian to the highest developed plant, the mode is one and the same by which the cells propagate themselves, that is by division.
As there are tens of thousands of different species even of "microbes," it is clear that we must deal with them in a very summary way. The evolution of the plant I reserve for a later chapter, and I must be content to suggest the development of one-celled animals on very broad lines.
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