FIG. 199. The sexual organs of a rockweed (Fucus vesiculosus) 



section of a female conceptacle with oogonia, showing tlie hairs which pro- 

 ject through the opening of the conceptacle into the water, and the loose net- 

 work of filaments in the interior of the plant ; B, mature oogonium containing 

 eight eggs; C, the discharge of the eggs from an oogonium; D, a group of 

 antheridia on the branching filaments which grow in tnfts over the sides and 

 bottom of the male conceptacles ; E, sperms very highly magnified, showing 

 elongated form and the two cilia at the side ; F, an egg lying free in the water 

 and surrounded by sperms. B, C, D, E, F, after Thuret 



211 



