460 GYMNOSTERMS LESS, xxxin 



In Gymnosperms we see an even more striking reduction 

 of the gamobium than in Selaginella. The female prothallus 

 is permanently inclosed in the megaspore, and the mega- 

 spore in the megasporangium : the ovaries also are greatly 

 simplified. The male prothallus is represented by the 

 smaller cell of the microspore, and no formation of sperms 

 takes place, fertilisation being effected by sperm-cells formed 

 from one of the products of division of the prothallial cell, 

 which migrate to the extremity of a tubular prolongation of 

 the larger or vegetative cell of the microspore, and finally 

 conjugate with the ova. 



It is worthy of notice that in spite of the specialised 

 method of fertilisation in Phanerogams, the process is 

 essentially the same as in other organisms. 



