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THE SEAWEEDS 
Fig. 3 . — Polysiphonia (after Yamanouchi, Tilden, and Smith): 
A, young carpogonial branch showing the supporting 
cell, carpogonial filament and carpogonium with 
trichogyne; B, the same in transverse section to 
show the pericentral supporting cell; C, carpogonial 
branch showing basal sterile filament initial and 
auxilary cell, with developing pericarp enclosing 
organ; D, after fertilization showing the zygote 
nucleus migrating into the fusion cell; E, carpo- 
sporophyte with gonimoblast filaments bearing carpo- 
sporangia; F, mature carposporangium ; G, carpospore; 
H, formation of tetraspores in sporophyte filament; 
I, mature tetrasporic filament. Nemalion (after 
Cleland and Smith): J, Nemalion thallus; K, sper- 
matangial branch; L, carpogonial branch at stage of 
fertilization showing spermatia, with male nuclei in 
the trichogyne; M, showing division of zygote after 
fertilization; N, carposporophyte showing gonimo- 
blasts with terminal carposporangia. 
