The microscope and its revelations . onjugationusually occurs between the cells of two distinct filaments,that happen to Ke in proximity to each other; and all thecells of each filament generally take-part in it at once. Theadjacent cells put-forth little protuberances, which come iatocontact with each other, and then coalesce by the breaking-down of the intervening partitions, so as to establish a freepassage between the cavities of the conjugating ceUs. Insome genera of this family (such as Mesocaqms), the con-jugating cells pour their endochromes into a dilatation of theaa2 356 MICROSCOPIC
The microscope and its revelations . onjugationusually occurs between the cells of two distinct filaments,that happen to Ke in proximity to each other; and all thecells of each filament generally take-part in it at once. Theadjacent cells put-forth little protuberances, which come iatocontact with each other, and then coalesce by the breaking-down of the intervening partitions, so as to establish a freepassage between the cavities of the conjugating ceUs. Insome genera of this family (such as Mesocaqms), the con-jugating cells pour their endochromes into a dilatation of theaa2 356 MICROSCOPIC POEMS OF VEGETABLE LIPE. passage that has been established between them; and it isthere that they comniingle, so as to form the spore or embryo-cell. But in the Zygnema (Fig. 108), which is among thecommonest and best-known forms of Conjngatese, the endo-chrome of one cell passes-over entirely into the cavity ofthe other; and it is within the latter that the spore isfomied (c), the two endochromes coalescing into a single FlGr. Various stages of the Mstory of Zygnema qidninum:—a, tliree cells,a, b, c, of a young filament, of which b is undergoing subdivision ,• b,two filaments in the first stage of conjugation, shomng the spiraldisposition of their endochiomes, and the protuberances from theconjugating ceils; c, completion of the act of conjugation, the endo-cluomes of the cells of the filament a having entirely passed-over tothose of filament b, iii which the sporangia are formed. mass, around which a firm envelope gradually makes itsappearance. Further, it may be generally observed, that allthe cells of one filament thus empty themselves, whilst all thecells of the other filaments become the recipients; here, there-fore, we seem to have a foreshadowing of the sexual distinc-tion of the generative cells into sperm-cells and germ-cells,which we have just seen to exist in the Confervacese (§ 198).And this transition will be still more complete, if (as Itzig-sohn has a
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