aw. im] TAHARA.— PERIODICAL LIBERATION IN S ARC A SSUM. 153 



Fie:. 1. Fie;. 2. 



of December Sargassum Horneri Ag. liberated man}' millions 

 of oospheres simultaneously which disappeared on the 1st. of 

 January. The receptacle of this species, favourable for obser- 

 vation, is bigger than that of the 

 former. The text figure 1 shows 

 the female receptacle of this plant 

 of 2Gth. December. The black 

 spots on its lower portion repre- 

 sent the discharged oospheres 

 which were cleared off on the 1st. 

 of January. (Fig. 2). 



It seems to me that the oo- 

 spheres of Fucus are not produced 

 with periodicity because the oo- 

 spheres of this genus, as it is well 

 known, can be liberated from con- 

 ceptacle at any time by several artificial processes. As far as 

 I experienced, Sargassum behaves very diflerentlv, and I tried 

 several times to apply similar processes in vain. 



SFMMARY. 



1. Liberation of oospheres in Sargassum takes place simul- 

 taneously, not only for a given plant but also for the all plants 

 of the locality. 



2. This simultaneous liberation proceeds in fortnightly 

 crops on a particular day with a fixed interval after the highest- 

 spring tide ; interval varies, however, in different species. 



3. The oospheres in one and the same receptacle arc not 

 discharged at one time bu1 in two or three successive fort- 

 nightly crops. 



