. Fresh-water biology. Freshwater biology. 74 (73) 75 (76) FRESH-WATER BIOLOGY Cells ellipsoidal or nearly spherical 73 Membrane widely separated from the chromatophore but connected with it by protoplasmic strands. Two cilia present. Sphaerella Sommerfeldt. Chromatophore netted, with two or more pyrenoids and a pigment spot. Asexual reproduction by longitudinal division, sexual by isogametes. A palmella condition may occur. Sphaerella- often assumes a red color, due to the presence of hemato- chrome, and is reported in a few cases as being the organism causing "red ; It was als
. Fresh-water biology. Freshwater biology. 74 (73) 75 (76) FRESH-WATER BIOLOGY Cells ellipsoidal or nearly spherical 73 Membrane widely separated from the chromatophore but connected with it by protoplasmic strands. Two cilia present. Sphaerella Sommerfeldt. Chromatophore netted, with two or more pyrenoids and a pigment spot. Asexual reproduction by longitudinal division, sexual by isogametes. A palmella condition may occur. Sphaerella- often assumes a red color, due to the presence of hemato- chrome, and is reported in a few cases as being the organism causing "red ; It was also supposed that 5. nivalis caused the phenomenon of "red snow," but the form described by Chodat shows the chloroplast as lying close to the membrane, so this is probably a Chiamydomonas. Fig. 143. Sphaerella pluvialis Flotow. X about 600. (After Schmidle.) Membrane not separated from the chromatophore 75 Two cilia and a pyrenoid present. Color rarely red. Chiamydomonas Ehrenberg. Cells elUpsoidal or spherical; chromatophore single, hollow, parietal; a pigment spot and,two cilia at the anterior end. Reproduction by vegetative division, also by copulation of gametes which are either ahke or sUghtly unlike as to size. Zygo- spore green or red. The products of the vegetative division may pass at once into a motile state with ciha, or may be non-motile, according to conditions in the sur- rounding medium. Fig. 144. Chiamydomonas ohioensis Snow. X 1000. COriginal.) 76 (75) Structure as in Chiamydomonas but with 4 cilia. Some include this genus under Chiamydomonas Carteria Diesing. The shape of the cells in the different species differ rather more than in Chiamydomonas; the structure of the cells, however, is identical, except for the cilia. Species also occur in much the same localities as Chiamydomonas but are less frequent. Fig. 14s. Carteria ohtusa Dill. X about 47s. (After Dill.). 77 (70) Cells united to form a colony of definite shape which is constantly . in motion 7
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
