. 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. "Michael Sars" North Atlantic Deep-sea Expedition (1910); Oceanography; North Atlantic Ocean. ,22 DEPTHS OF THE OCEAN Bergon. Karsten. Peridineae. which, according to Bergon's investigations^ would seem to be zoospores, and which Karsten assumes to be sexual cells. Karsten has observed the formation of microspores in an antarctic diatom, Corethroii valdivicE (see Fig. 225), and in the same microscop
. 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. "Michael Sars" North Atlantic Deep-sea Expedition (1910); Oceanography; North Atlantic Ocean. ,22 DEPTHS OF THE OCEAN Bergon. Karsten. Peridineae. which, according to Bergon's investigations^ would seem to be zoospores, and which Karsten assumes to be sexual cells. Karsten has observed the formation of microspores in an antarctic diatom, Corethroii valdivicE (see Fig. 225), and in the same microscopic preparations found amalgamations of small cells resembling microspores. We cannot yet, however, consider this conclusively settled. We do not know the life-history of the numerous small spores after they have emerged from the mother-cell. We can only hope that the centrifuge will enable us to study the most diminutive andsensitivecells immediately after capture, and that ^ ^ ¥ } II ^ we shall thus suc- ceed in solving this problem in the biology of H Fig. 225.—Microspore-formatio.\ 01 Cokethron in different development stages (="-1"). Ripe microspores in the cell to the right. (Karsten.) Peridinese are mobile algae fur- nished with two cilia. Several species can pro- duce brilliant phosphorescence. Their cells are highly organised, with adistinctdif- ference between the anterior and posterior ends, and between the dorsal and ventral faces. The cell-wall is built up entirely of organised matter, which dissolves soon after the death of the cell. Peridinese are therefore not noticeable in the deposits of the ocean-bottom, which is one of the reasons why, until quite recently, they were but slightly and imperfectly known. A number of laminae, characteristic in shape and position, compose the cell-wall. On the posterior side there is a characteristic furrow, with a pore for one of the cilia, which can be withdrawn spirally into a sheath (see Fig.
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1912
