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separating a smaller lower from a larger upper part. The shape 

 of the embryosac consequently becomes biscuit like. Before the 

 pollentube has reached the embryosac the lower smaller part 

 fills itself with a tissue to be considered as a prothallium. 



The nuclei in the larger upper part remain free, no cell 

 formation takes place in that part. 



The top of the prothallium occasionally contains archegonium- 

 like bodies, which even if this interpretation of their nature 

 be right, yet are rudimentary as they are never fertilised. 



At this stage the embryosac awaits fertilisation. 



At the moment of coming near to the embryosac the pol- 

 lentube contains one vegetative and two generative nuclei. 



One or more pollentubes penetrate into the embryosac, either 

 at the top, or at the sides but always above the constriction 

 viz. in the part which contains free nuclei only. 



Each of these pollentubes discharges its two generative nuclei 

 into the embryosac. 



Each generative male nucleus copulates with one of the free 

 nuclei of the fertil part of the embryosac. Consequently two 

 copulation products belong to every pollentube penetrated. The 

 copulation products are very much larger than the embryosac 

 nuclei and therefore easily seen. 



Every product of copulation subsequently surrounds itself 

 with a denser mass of protoplasm. 



The cell thus originated forms a cellulose membrane, it is 

 now called a Zygote. 



Some of the remaining free nuclei of the embryosac surround 

 themselves with plasma and cellulose-walls thus forming what 

 the author calls retarded prothallial cells of the fertil part of 

 the embryosac. The other free nuclei perish sooner or later, 

 sometimes very much later. 



The zygotes frequently become concrescent with the tips of 

 the pollentubes belonging to them. The whole then simulates 

 a proembryo forming an embryo proper, the pollentube looking 

 like a suspense r. 



The zygotes frequently remain free. 



