Butters: OBSERVATIONS ON TRICHOGLCEA LUBRICA. 19 



cylindrical, averaging 10.7 x8.6 mic. It remains sterile, form- 

 ing a stalk cell, or placenta {Figs. 12-16, S). It contains a 

 distinct nucleus, and has thin cytoplasm, appearing noticeably 

 clearer than the adjacent cells. Its cell wall is often much 

 thicker than that of the auxiliary stalk cell, or of the central 

 cells of the cystocarp. Throughout the development of the 

 cystocarp the cytoplasmic connections between the proximal 

 cells of the fertile filament, the auxiliary stalk-cell, the stalk- 

 cell, and the basal fertile cells of the cystocarp can be easily 

 seen. 



The distal cell formed by the first division of the carpogonial 

 cell has very dense cytoplasm (Fig. 12, c). It soon divides 

 again, transversely, and then each of the cells thus formed 

 divides one or more times in planes perpendicular to the first 

 division, forming thus an almost spherical mass of several cells 

 arranged in two tiers (Figs. 13, /^). These form the central 

 cells of the cystocarp. Branching gonimoblast filaments arise 

 as outgrowths of these central cells (Figs, /j, 77). The corti- 

 cal cells of the gonimoblast are very thin walled, and have 

 dense cytoplasm and distinct nuclei. When the gonimoblast 

 filaments reach their full growth the terminal cells become 

 thick-walled, and their cytoplasm becomes very dense. Even- 

 tually the contents of each of these cells escapes as a spore, 

 leaving the empty cell-wall still attached to the gonimoblast 

 filament. 



As a secondary result of the fecundation of the procarp, 

 sterile filaments, resembling the ordinary cortical filaments, 

 arise from the cells immediately proximal to the auxiliary stalk- 

 cell. These filaments correspond to the pericarp which com- 

 pletely surrounds the cystocarp of many Rhodophycese, but in 

 this case they never form more than an irregular and imperfect 

 covering about the base of the cystocarp. 



It will be seen that the structure and development of the cys- 

 tocarp is essentially that found throughout the Nemalieae. The 

 general features of the reproduction in this group were described 

 by Bornet and Thuret in the year 1867 (Bornet, E., and Thuret, 

 G., Recherches sur la fecundation des Floridees, Annales des 

 Sciences Naturelles, Series V., 8: 141-145. 1867) sincewhich 

 time the phenomena of reproduction have been studied more or 

 less in detail in numerous plants of this group. (See Janczewski, 

 Notes sur le Developpement du Cystocarp dans les Floridees, 



