Oogonium Liberation and the Embryogeny oï Some Fucaceous Algae. H 



To ascertain, if possible, the origin of this central group of 

 rhizoid I made some microtome-sections of the sporehngs in this 

 stage. Text-Fig. 2 was drawn from one of such 

 sections. The two rhizoids in shade are the 

 descendants of the rhizoid cell formed by the 

 second segmentation wall. Other rhizoids situated 

 in the central portion seem to have been derived 

 from the body cells, without having any direct 

 relation to the above mentioned rhizoid cell. In 

 T.- o ^^Af^ the later development the number of rhizoids 

 gradually increases. The rhizoids are at first 

 unicellular but later we find several partitions here and there (Fig. 

 16, PL. II). Under a strong magnification we see pecuhar thicken- 

 ings on the cell walls of the rhizoids, which remind us of the 

 spiral thickenings of tracheids of higher plants (Fig. 16 b, PL. II). 

 The cells contain small granules of what seems to be a fat-like 

 substance, so far as can be seen by the reactions of osmic acid and 

 Sudan III. The same substance is found not only in the rhizoids 

 but also very abundantly in the body cells in general. 



For a long time, the shape of the sporelings remains oval or 

 elliptical, but later becomes like a flask and at last at the boundary 

 between the slender and the swollen part of the sporeling, there 

 grows a neAv branch (Figs. 17-20, PL. II). This is the last stage 

 that I observed at Misaki. 



Cystophyllum. 



The segmentation process in the rhizoid 

 cell of this plant difïers considerably from 

 that above described ; that is, in this plant 

 before the rhizoid formation begins, the 

 rhizoid cell is already divided into about 30 

 small cells. Text-fig. 3 is the surface view 

 of the rhizoidal potion of the sporeling and 

 text-fig. 4 presents a median longitudinal 

 section of the same. In the latter figure, 

 we can see the two-storied arrangement, a Fig. 3. x24o 



