. The microscope and its revelations. end themselves into branches,A so as to form an arborescentfrond. These branches, how-ever, are not separated fromthe stem by any interveningpartition, except those partswhere the generative organsare produced; but the wholefrond is composed of a simplecontinuous tube, the entirecontents of which may bereadily pressed out through anorifice made by wounding anypart of the wall. The genusVaucheria may be selected as aparticularly good illustration ofthis family, its history havingbeen pretty completely madeout. Most of its species arcinhabitants of fresh wat
. The microscope and its revelations. end themselves into branches,A so as to form an arborescentfrond. These branches, how-ever, are not separated fromthe stem by any interveningpartition, except those partswhere the generative organsare produced; but the wholefrond is composed of a simplecontinuous tube, the entirecontents of which may bereadily pressed out through anorifice made by wounding anypart of the wall. The genusVaucheria may be selected as aparticularly good illustration ofthis family, its history havingbeen pretty completely madeout. Most of its species arcinhabitants of fresh water, biitsome are marine; and theycommonly present themselvesin the form of cushion-likemasses, composed of irregularlybranching filaments, which, al-though they remain distinct,are densely tufted together and FIG. 426.—Successive phases of generative variously interwoven. Someprocess in Vaucheria sessilis: at A are species form dense green matsseen one of the horns or antlierids (a) i -i • a ? on damp soil in flower-pots, & B and one of the oogones (&, as yet un-opened; at B the antherid is seen inthe act of emitting the, antherozoids (e),of which many enter the opening at theapex of the oogone, whilst others (d) The formation of motile gonidsor zoospores may be readilyobserved in these plants, the winch do not enter it, la\ their cilin. whole process usually occupyinguntil they become motionless; at C the }n\t a Very short time. Theorifice of the oogo s closed again by ,• ,>,i £i theformati. Ee cellul *oat around extremity of one of the filaments the oosphere, thus constituting an obspore. usuallv suells up in the form of a club, and the endochronic accumulates in it so as to give it a darker hue than the rest;a separation of this part from the of the filament,by the interposition of a transparent space, is next seen; a newenvelope is then formed around the mass thus cut oil: and at lastthe membranous \\alloflhc investing tube gives way. and the zoo- SI
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
