. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Antlieridia of Pterisaquilina, 260 diam. On the right is seen an antheridium from which cells containing antherozoids are escaping; in the centre another, which has not yet burst; on the left a third, which has already discharged its contents. (Thuret). filaments (antherozoids.) In each filament the extremity which is directed forwards du- ring motion, is broader than any other part, while the opposite extremity (posterior) tapers off into a long filament. The anterior coil of the spiral bears on the surface furthest fro
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Antlieridia of Pterisaquilina, 260 diam. On the right is seen an antheridium from which cells containing antherozoids are escaping; in the centre another, which has not yet burst; on the left a third, which has already discharged its contents. (Thuret). filaments (antherozoids.) In each filament the extremity which is directed forwards du- ring motion, is broader than any other part, while the opposite extremity (posterior) tapers off into a long filament. The anterior coil of the spiral bears on the surface furthest from its axis a number of delicate cilia. The motion of the antherozoid is of two kinds—of progression and of revolution round the axis of the spiral. 81. The archegonia. — At a period somewhat later than that at which the rudiments of the antheridia begin to appear, there commences on the inferior aspect of the prothallium,and in the immediate neighbourhood of the notch by which its anterior margin is bisected so as to form two lobes, an active development of new cells. The result of this is the formation of a cushion-like projection of the surface bor- dering the notch above mentioned, upon the anterior aspect of which the archegonia are formed. 82. Each archegonium takes its origin from a cell, which is distinguished from those sur- rounding it by the comparative abundance of granular mucus which it contains, and by the presence of a distinct central vesicular nucleus. This cell divides by a horizontal septum into a superior and an inferior portion. It is from the latter, which is hemispherical, that the papilla which forms the rudiment of the pro- jecting portion of the organs is formed. It consists, as in theHepaticae and Mosses, of four contiguous columns of cells, each of which is a half segment of a cylinder, the whole being surmounted by a hemispherical terminal cell. In the further development, varieties are often observed, even on the same prothallium. This is depe
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