. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. if* 1 1 .. f*5®^P\ %mb& Fig. 212.âCell-wall of a Diatom {Coscinodiscus subbulliens), 3f-°. a, External view ; b, vertical section ; c, section in cell-division. at some point where they can mutually protect each other from the harmful effects of the rays (Fig. 213, b and c). This has been demonstrated by Schimper. The assimilation of carbonic acid Schimper. produces a fat oil, which may for
. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. if* 1 1 .. f*5®^P\ %mb& Fig. 212.âCell-wall of a Diatom {Coscinodiscus subbulliens), 3f-°. a, External view ; b, vertical section ; c, section in cell-division. at some point where they can mutually protect each other from the harmful effects of the rays (Fig. 213, b and c). This has been demonstrated by Schimper. The assimilation of carbonic acid Schimper. produces a fat oil, which may form into comparatively large drops. Cells are produced by Ceil division. division. The nucleus and protoplasm divide into two parts, the valves are pushed a little apart, and two new valves develop within the old ones. Thus each of the daughter-cells gets one of the I â J u. valves from the mother-cell tgr and a new valve that joins on to it (see Fig. 212, c). When once the valves have acquired their shape they seem incapable of expanding, so that the cell FlG- 2I3- generations will gradually be- a, b, Lauderia anmdata. a, Cell with the pig- «- J U 1 ment granules (chromatophores) in normal COme Contracted in the plane position, collected early in the morning ; b, [n Which division takes place. chain from the surface of the sea, 3 p. M., T r .. , - .* _ chromatophores congregated at the ends of 11 IOllOWS that the Cavity OI the cells; c, Detonula schrtxderi in the same f-Vip ppl] will also be dimin- condition. All ±*fi. ished, though at the same time the perpendicular axis of the plane of division is frequently slightly prolonged. Algae can, however, regenerate their original size, by throwing off their old valves, growing into a larger bladder with a thin expansible skin, and forming within it new valves that are two or three times as large as the old ones. This is the so-called auxospore development (see Fig. 214). Auxospore Diatoms occur in quantities over the whol
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1912
