404 



STRXJCTTJRE AND LIFE HISTORIES 



through the neck-canal of the archegonium, into the 

 archegonial chamber. FertiHzation, 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,^ 

 Webber : 



Fig. 301.' — Fertilization in Zamia floridana. The male and female nuclei 

 are fusing; h, remains of the cillia 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, 



' Sperms were discovered in Cycas by two Japanese botanists, Hiras^ 

 and Ikeno. 



