182 



DEVELOPMENT OF ECTOCARPUS 



(Fig. 119). The zoospores are developed in certain cells of 

 the upper branches. It is important to note in the brown algae, 

 that the reproductive cells are generally confined to special parts 



FIG. 119. Reproduction of Ectocarpus: A, branch bearing several spo- 

 rangia, sp; g, zoospore enlarged. B, branch bearing gametangia, gm. 

 C, the upper motionless gamete (female) surrounded by several still 

 motile gametes (males). D, fusion of the gametes, below the resulting 

 gametospore. 



of the plant and not promiscuously developed as in the green 

 algae. This marks a decided advance in the evolution of the 



