THE LIFE-HISTORY OF A FERX 



medium of transit of the spermatozoids to the ovum. But the movements 

 of the spermatozoids are not subject to blind chance : the chemiotactic 

 attraction of the archegonium directs the spermatozoids through the water, 

 towards the open neck, which they may be seen to enter, and finally one 

 of the spermatozoids coalesces with the ovum : fertilisation is effected 



Vouuu 



FIG. 14. 



i' of Adicintinn conciininiu. L =le;if-quadiant ; .9 = .stem-quudrant ; 

 = root-quadrant ; A=foot-quudrunt. (After Atkinson.) 



by the absorption of the male nucleus in that of the egg (Figs. 13 

 and 13 to). Thus the presence of external fluid water is essential for the 

 process of fertilisation : without it the prof Itall its is unable to achieve that 

 object of its existence. 



The consequence of fertilisation is the growth and segmentation of 

 the ovum, or zygote, as it may now be called, to form a mass of 

 embryonic tissue, which at first remains embedded in the tissue of the 



