. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Corpusculum of the same in section, immediately be- fore impregnation, 200 diam. Its cavity is filled with transparent vesicles, and bounded superiorly by four granular cells, the position and relations of which recal very forcibly the arrangement which presents itself in the rudimentary aix-hegonium among the higher Cryptogamia. 104. The growth of the pollen tube, which has been for many months arrested, at last re- commences ; the membrane of the summit of the embryo-sac at the same time becomes attenuated, and immedia
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Corpusculum of the same in section, immediately be- fore impregnation, 200 diam. Its cavity is filled with transparent vesicles, and bounded superiorly by four granular cells, the position and relations of which recal very forcibly the arrangement which presents itself in the rudimentary aix-hegonium among the higher Cryptogamia. 104. The growth of the pollen tube, which has been for many months arrested, at last re- commences ; the membrane of the summit of the embryo-sac at the same time becomes attenuated, and immediately after is pene- trated by the narrowed end of the pollen tube, which is brought into immediate con- tact with the summit of the corpusculum, the four cells which previously surmounted it having disappeared. At this time, the corpus- culum exhibits in its interior, at the end oppo- site the pollen tube, a single vesicle, much larger than those by which it is surrounded, within which is afterwards developed a se- condary cell, occupying more than half its cavity. This cell, which is convex above, is applied by a flattened inferior surface against the wall of the corpusculum. It soon divides by a longitudinal septum into two, each of which is nucleated. These two cells, which occur throughout the Conift-rae, form the commencement of the suspensor. They next divide by a second pair of vertical septa, at right angles to the first; and in each of the four cells which result, a succession of hori- zontal septa are formed, by which they are converted into four vertical columns inti- mately united to each other. The suspensor lengthens in one direction only, partly by the repeated division of the four inferior terminal cells, partly by the interstitial growth of those first formed. Soon it bursts through the Fig. Corpusculum of the same, 120 diam. The four cells by which it is bounded superiorly have disappeared. The pollen tube is still in contact, by its flattened extremity
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