. Fresh-water biology. Freshwater biology. THE FRESH-WATER ALGAE 143 65 (66) Chromatophore an axial plate, with several pyxenoids. Zygospore lens-shaped or flattened and angled, in the conjugating tube. Mougeotia Wittrock. Conjugation ladder-like or between two adjoining cells of the same filament. Zygospore in the inflated conjugating tube, separated from the conjugating cells by two or more transverse Fig. 140. Mougeotia sp. «. showing the surface of the chlorophyll plate, b. showing the edge of the chlorophyll plate. X about 500. (Original.) 66 (65) Vegetative portion as in Mougeoti
. Fresh-water biology. Freshwater biology. THE FRESH-WATER ALGAE 143 65 (66) Chromatophore an axial plate, with several pyxenoids. Zygospore lens-shaped or flattened and angled, in the conjugating tube. Mougeotia Wittrock. Conjugation ladder-like or between two adjoining cells of the same filament. Zygospore in the inflated conjugating tube, separated from the conjugating cells by two or more transverse Fig. 140. Mougeotia sp. «. showing the surface of the chlorophyll plate, b. showing the edge of the chlorophyll plate. X about 500. (Original.) 66 (65) Vegetative portion as in Mougeotia but zygospore not known. Gonatonema Wittrock. Aplanospores produced between two transverse mem- branes near the center of an elongated cell. Spore membrane double. Fig. 141. Gonatonema ventrkosum Wittrock. X 2S0. (After West.) 67 (2) Plants unicellular or of few cells. Chromatophore one or more parietal bodies, rarely central ; . 68 68 (190, 249) Plants unicellular, or of few cells united into minute families; frequently imbedded in gelatinous substance. Order Protococcales . 69 Each cell carries on all functions independently, and complexes may be regarded as an aggre- gate of individuals. Three forms of reproduction may occur: i, purely vegetative; 2, by asexual zoospores; 3, by isogametes. More than one method frequently occurs in one species; the vegetative reproduction may be by simple fission or internal division. 69 (89) Vegetative cells or colonies for a portion or the whole of their exist- ence motile Family Volvocaceae . 70 70 (77) Cells single or in clusters, not forming a definite colony 71 f I (72) Cells spindle-shaped; chromatophores several, indefinite, with two or more pyrenoids and a pigment spot. Chlorogonium Ehrenberg. Cells with two cilia; membrane very thin, pigment spot in anterior part. Numerous vacuoles and several pyrenoids present. Division transverse. Reproduction by isogametes. Wille makes this genus a section under Please note tha
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
