BROWN ALGAE 



383 



antheridia (Fig. 319, A). The female conceptacle is of like structure, 

 but bears unbranched hairs, and associated with them are the large 



via 



FIG. 322. 



Ectocarpus secunda. (After Sauvagean.) i. filament bearing plurilocular sporangia 

 (or gametangia) : $ male, ij> female, ii. male gametes, iii. female gametes. 



, , . , . 



iv.-vi. stages in fertilisation, vii., viii. zygotes. (i. x 200 ; ii.-viii. x 500.) 



oogonia, which are large enough, when mature to be seen with the 

 naked eye (Fig. 319, B). 



FIG. 323. 



Ctttleria multifida, showing the smaller, male gametangia (or plurilocular 

 sporangia), and the larger female. Top-left are spermatozoids, top-right are ova. 

 Below are three stages of fertilisation. ( x 500.) (After Reinke.) 



The antheridium itself is an oval unicellular body, surrounded by 

 a cell-wall. When young it contains a single nucleus, which divides 



