FERTILIZATION AND FRUIT-FORMATION IN CRYPTOGAMS. 



63 



concave inner face of each plate a cylindrical or conical cell projects, carrying upon 

 its summit another, capitate, cell. Each of these head-cells is surmounted by long 

 .strings of cells, of which the lowest segments are spherical or cylindrical, whilst the 

 rest are short discs (see fig. 206 5 ). The whole structure may be likened to a whip 

 with many thongs, and the stalk-cell projecting from the plate has hence been 

 called the " manubrium " or handle. So long as the eight plates of the sphere are 



Fig. 206. -Fruit-formation in Stoneworts (Characese). 



1 Chara fragilis. 2 Piece of the same with amphigonia and antheridia on the branches. 8 A single branch with amphigonia 

 and antheridia. * An antheridium. A plate of the antheridium with manubrium and cells grouped in the form of thongs 

 and containing spermatozoids. 6 Several cells from one of the whip-like filaments ; the cells in the middle contain each a 

 spermatozoid, the spermatozoid is escaping from the uppermost cell, the lowest cell is already vacated. * A single sperma- 

 tozoid. 8 Amphigonium inclosing the oogonium. 1 natural size ; a x 10 ; X 15 ; * x 35 ; * x 100 ; x 300 ; 7 x 500 ; > 



closed, these manubria project towards the centre of the hollow sphere, and the 

 rows of cells proceeding from the manubria are conglomerated into a ball. But as 

 ;soon as the plates separate and the sphere falls to pieces, the ball is untwisted and 

 its parts assume the appearance shown in fig. 206 5 . By this time a spiral sper- 

 matozoid has developed from the protoplasm in each of the discoid segments of the 

 filaments, and may be seen lying within its cell (see fig. 206 6 ). But almost 

 immediately afterwards these cells open, and the spermatozoids, which are provided 

 .-at one end with a pair of long cilia, escape and whirl about in the surrounding 



