164 



SEAWEEDS 



and Anadyomcne, not in special zoosporangia but in 

 any of the ordinary thallus cells. The zoospores are 

 bi- ciliated, with a hyaline anterior end and a red spot. 

 Nothing is known of their further history. 



In Valonia vcntricosa (Fig. 46) there arise by free 

 cell-formation a large number of spores with cell- 



FIG. 49. Boodlea coacta. a, thallus filaments; &, two haptera highly 

 magnified. 



membranes. They do not all arise simultaneously, 

 since in some specimens comparatively few spores 

 are to be found, while a considerable amount of 

 free protoplasm remains ; in others again the spores 

 are very numerous and the amount of unused 

 protoplasm is a mere trace. Somewhat similar spores 



