404 
STRUCTURE AND LIFE HISTORIES 
through the neck-canal of the archegonium, into the 
archegonial chamber. Fertilization, here as always, is 
completed by the fusion of the sperm and the egg-nuclei 
(Fig. 301). The behavior of these little sperms in an allied 
genus, Zamia, is thus described by their discoverer, 1 
Webber: 
FIG. 301. Fertilization in Zamia floridana. The male and female nuclei 
are fusing; b, remains of the cilia of the sperm. (After Webber.) 
"In removing the nearly mature pollen- tubes the sperm- 
atozoids are found to be in various stages of development, 
as would be expected. In many cases tubes have been 
observed, before cutting them off, in which the two sper- 
matozoids had pulled apart and were swimming free in the 
protoplasm. In some instances their movement in the 
pollen- tube, before it is injured, can be observed with the 
aid of a hand lens. 
''It is an interesting sight to see the two giant sper- 
matozoids moving around vigorously in the pollen-tube, 
1 Sperms were discovered in Cycas by two Japanese botanists, HirasS 
and Ikeno. 
