CARPOSPOREM. 



3OT 



cells, the outside of the globe increasing more rapidly than the inside : the middle cells 

 (m), which form the manubria, remain attached to the centres of the shields, but are 

 separated from one another by the tangential growth of the shields; they grow slowly in 

 the radial direction : the innermost cell i of each octant is rounded off and becomes the 

 capitulum. 



The cellyin Fig. 200, D, now also grows quickly, and forces itself between the four 

 lower shields into the interior of the globe ; it becomes the flask-shaped cell, upon the 

 apex of which rest the eight capitula. In Fig. 201 this condition of the antheridium 

 is shown in longitudinal section; here the walls of the capitula bound the intercellular 

 spaces which have now been formed and are filled with fluid ; they put out branches (c) 

 which become septate, and again ramify ; and these branches elongate by apical growth 

 and also become septate. Their ^asal cells swell up into a roundish shape, and form 

 the secondary capitula, upon which stand the whip-shaped filaments, consisting of the 

 discoid cells which are the mother-cells of the antherozoids. (Compare Fig. 201 with 

 Fig. 198, B.) 



The antheridia of Chara fragilis are produced by metamorphosis of those leaflets 

 which form the innermost row on a leaf, and in fact, as is shown in Fig. 203, the 

 development advances downwards on the primary leaf. The succession of cells and the 

 mode of growth show no noteworthy differences from those of Nitella ; the flask-shaped 

 pedicel is here placed on a small cell wedged in between the cortical cells, which is the 

 central cell of the basal node of the leaflet : Braun asserts that this cell is present also in 

 sterile leaves, but I have not succeeded in finding it. 



Antherozoids. The whip-shaped filaments in which the antherozoids arise do not 

 grow merely at their apex, but have also an intercalary growth. This is shown by the 

 elongated cells in the middle of young filaments, each with two nuclei, between which no 

 division-wall has yet been formed (Fig. 198, C). The longer the filaments become, the 

 more numerous are their divisions, until at length the individual cells have the appearance 

 of rather narrow transverse discs. The further development of the contents of these 

 mother-cells of the antherozoids progresses backwards from the end of the filament ; 

 the antherozoids are formed in basipetal order in each filament. At first the nucleus 

 of each mother-cell lies in its centre, later it places itself in contact with one septum ; 

 the nucleus then disappears, and its substance becomes mixed with that of the pro- 

 toplasm, which now forms a central discoid mass in the mother-cell, surrounded by 

 a hyaline fluid (Fig, 198, E). From this is formed the antherozoid, and, when it is 

 mature, there is no granular protoplasm left over in the cell ^. The antherozoids begin 

 |to rotate even while within their cefl, and escape out of it after the rupture of the 

 ^antheridium ; the filiform antherozoid has in Nitella 2 or 3, in Chara 3 or 4 coils; the 

 ^posterior thicker end contains a few glistening granules. 



The De'velopment of the Carpogonium has already been described in detail by A. Braun ; 

 [I have also studied it in Nitella ft enilis and Chara fragilis. In Nitella fexilis it springs 

 from the node of the leaf beneath the antheridium (Fig. 199, B and C) ; its origin is 

 .much later than that of the latter. Fig. 202, J, represents a very young carpogonium ; 

 ^the lowest cell of the pedicel [b] bears the small nodal cell with the five rudiments of 

 Ithe enveloping tubes {h), (two only are shown here in longitudinal section). Above the 

 jnodal cell lies the apical cell (j) of the branch, for such is the nature of the carpo- 

 ^gonium. B represents a further stage of development, in which the first of the cells, 

 [designated by A. Braun the ' Wendungszellen,' has already made its appearance, and 

 ■two septa have also appeared in the upper part of each enveloping tube; these 

 [upper short cells are raised up by the intercalary growth of the tubes, above the apical 

 11, and form the crown ^ in C and D. The lowest of the cells of the crown each 

 , forms a prolongation projecting inwards and downwards, as shown in Fig. 202 C and 

 JD, so that the whole carpogonium resembles a ' lobster-pot.' The spiral torsion of 



' Compare the opposite view of Schacht, Die Spermatozoiden im Pflanzenreich, 1864, p, 30. 

 [The account given ia the text is confirmed by Strasburger, Zellbildung u, Zelltheilung, 1880.] 



