THE ALGAE 



II' 



produced. In this case not only does the terminal cell become a gametangium 

 but one or more of the cells of the filament may produce lateral branches 

 terminating in gametangia. 



Fig. 98. — Cutleria multifida. Apex of a branch of the 

 thallus showing trichothallic growth. 



1^ 



*^y^. 



Male gamet- 

 angium 



Fig. 99. — Cutleria multifida. Section of thallus showing a cluster 

 of male gametangia on branched stalks. 



Inside the gametangium the nucleus divides and two cells are formed 

 separated by a wall ; more divisions follow, until the greatly enlarged 

 gametangium consists of a number of parallel rows, each containing twent>'- 

 four or more cells. Each of these cells finally becomes a male gamete 



