THE SYNCHYTRIAN NUCLEUS 



83 



FIG. 22. S. ENDOBIOTICUM, SEXUAL GENERATION, a, 4 stages of 

 syngamy, the lowest shows recession of the 2 flagella ; b, 5 stages in 

 penetration, the transverse line is the surface of a host-cell ; c, cell 

 with young zygote smaller than cell-nucleus ( X 400) ; d, the parasite 

 is larger and lies below the cell-nucleus ; e, division of host-cell 

 containing 5 parasites, the latter remain in the lower half of the cell ; 

 /, cell with large parasite now separated from the surface by previous 

 divisions of host-cell ; g, part of a parasite, it has its own capsule 

 and, outside that, a second derived from the host-cell, its nucleolus 

 has discharged chromatin into the cytoplasm, where chromidial 

 granules are seen, x 800 ; Ji, zoospores beginning to be formed from 

 chromidia, X 1650 ; i, j, further stages in zoospore-formation ; k, 

 zoospores x 780, living (left) and fixed and stained (right) ; I, zoo- 

 spore x 1650, nucleus, blepharoplast, and joining strand seen. After 

 K. M. Curtis. 



The Gametic Nucleus. Fusion of the two gametic nuclei 

 is shown in four stages at a, and the part played by the 

 nucleus of the zygote during penetration of the host-cell 



