GENERATIVE APPARATUS OF FUCACE.E. 



347 



which, when discharged by the rupture of the containing cell, have 

 for a time a rapid undulatory motion, whereby those Antherozoids 

 are diffused through the surrounding liquid. Lying amidst the 

 filamentous mass, near the walls of the cavity, are seen (Fig. lb* 2) 



Fig. 163. 



Antheridia and antherozoids of Fucus platycarpus : — A, branch- 

 ing articulated hairs, detached from the walls of the receptacle, 

 bearing antheridia in different stages of development ; b, an- 

 therozoids, some of them free, others still included in their 

 antheridial cells. 



numerous dark pear-shaped bodies, which are the Sporangia, or 

 parent-cells of the 'germ-cells.' Each of these sporangia gives 

 origin, by binary subdivision, to a cluster of eight cells, which is 

 thence known as an ' Octospore ;' and these are liberated from 

 their envelopes before the act of fertilization takes place. This 

 act consists in the swarming of the Antherozoids over the surface 

 of the Grerm-cells, to which they communicate a rotatory motion by 

 the vibration of their own filaments : it takes place within the 

 Receptacles in the hermaphrodite Fuci, so that the spores do not 

 make their exit from the cavity until after they have been fecun- 

 dated ; but in the monoecious and dioecious species, each kind of 

 Receptacle separately discharges its contents, which come into 

 mutual contact on their exterior. The Artheridial cells are usu- 

 ally ejected entire, but soon rupture so as to give exit to their 

 filaments ; the Sporangia of the female receptacles discharge their 

 globular octospores within the receptacle ; and these, soon after 



