The microscope and its revelations . sely as well as longi-tudinally, so that a flattened leaf-like expansion (d) is produced,so closely resembling that of a young Marchantia as to bereadily mistaken for it. This expansion, vv^hich is termed theprot/iallmm, varies in its configuiation in different species ; butits essential structure alvi^ays rcDiaius the same. Prom itsunder surface are developed, not merely the root-fibres (a, b)which serve to fix it in the soil, and at the same time tosupply it with moisture, but also the antheridia and arche-gonia, which constitute the true representatives
The microscope and its revelations . sely as well as longi-tudinally, so that a flattened leaf-like expansion (d) is produced,so closely resembling that of a young Marchantia as to bereadily mistaken for it. This expansion, vv^hich is termed theprot/iallmm, varies in its configuiation in different species ; butits essential structure alvi^ays rcDiaius the same. Prom itsunder surface are developed, not merely the root-fibres (a, b)which serve to fix it in the soil, and at the same time tosupply it with moisture, but also the antheridia and arche-gonia, which constitute the true representatives of the essentialparts of the flower of higher Plants.—Some of the antheridiamay be distinguished at an early period of the development ofthe prothallium {h, h); and at the time of its complete evolutionthese bodies are seen in considerable numbers, especially about GENERATITE OEGANS OF PEENS. 403 the origins of the root-fibres. Each has its origin in a pecuHarprotrusion that takes-place from one of the cells of the pro- FiG. Development of the Antheridia and Antherozoids of Fteris ser-rulata:—a, projection of one-of the cells of the prothallium, showingthe anthericUal cell, b, with its sperm-cells, e, within the cavity ofthe original cell, a;—b, antheridium completely developed; a, wallof antheridial cell; e, sperm-cells, each enclosing an antherozoid;—c, one of the antherozoids more highly magnihed, showing a, itslarge extremity, h, its small extremity, d, d, its cilia. thallium (Fig. 146, a, a) ; fliis is at first entirely filled withchlorophyll-granules ; but soon a peculiar free cell [b) is seenin its interior, filled with mucilage and colourless cell gradually becomes fiUed with another brood of youngcells {c), and increases considerably in its dimensions, so as tofill the projection which incloses it; this part of the originalcavity is now cut-off from that of the ceU of which it was anoffshoot, and the antheridium henceforth ranks as a distin
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Keywords: ., bookcentury1800, booksubjectmicroscopes, booksubjectmicroscopy
