SEED-BEARING PLANTS 
403 
elongates the generative cell passes down it, becoming 
divided into two sperm-cells. These sperm-cells are 
remarkably interesting little bodies, bearing a large num- 
FIG. 300. Dioon edide: upper part of an ovule at the time of fertiliza- 
tion, showing integument, nucellus, male gametophytes (germinating 
pollen-grains), and female gametophytes (embryo-sacs). Reconstructed 
from sections of several ovules. (After Chamberlain.) 
ber of cilia, by the motion of which they are carried, in 
the completion of their journey to the egg, through the 
watery solution emptied from the pollen-tube, to and 
