PHTOOPBYTA. 



165 



rounding wall {B). Before rupturing, however, the an- 

 therids detach themselves and float in the water with their 

 contained antherozoids. 



292. The oogone is a globular or ovoid short-stalked body 

 containing eight germ-cells. The oospheres escape from the 

 oogone surrounded by an investing membrane, which floats 

 out through the opening of the conceptacle, where it finally 

 ruptures and sets the germ-cells free (//, Fig. 91). The 

 antherozoids, which are liberated at about the same time. 



Fio. 91.— Sexual organs of Rockweed (F. vesiouloausl. A, antherids ; 

 B, antherozoids; J, oogone and hairs; II, escape of oospheres; III, 

 oosphere surrounded hy antherozoids ; IV, V, germination of oospore. 

 (Magnified 160 times ; B, 360). 



gather around the inactive oospheres in great numbers, 

 and by the vigor of their movements sometimes actually 

 give them a rotary motion {III). The result of their 

 coming together is the fertilization of the oospheres, and 

 their transformation into oospores by the secretion of a 

 wall of cellulose on each one. 



293. In germination the oospore lengthens and under- 

 goes division into numerous cells; at the same time it 



