316 



BIOLOGY. 



[Book .iv. 



contains them and has engendered them is called antheridion 

 (Fig. 45). Once set at liberty, the antherozoids penetrate into the 

 oogon, by a special opening, and confound themselves with the 

 mass of the oosphere which they impregnate.^ 



.■*T:"'te. 



Fig. 44. 



A, zoospore covered witli vibratile cilia. 



B, zoospores fumislied only 'witii two vibratile cilia. 



C, evolution of a zoospore of Vaucheria : a, filament before the fractification : &, at the 

 'extremity of the filament an accumulation of protoplasm has formed, whence is to proceed 

 the zoospore ; c, zoospore, almost completed, and already furnished with its enveloping 

 membrane, projects beyond the filament. 



D, Numerous zoospores set at liberty. 



Apart from the abundance of organs, of apparatus, which in 

 the highest animals are the means of generation, the same 

 description of fecundation could serve equally for the algse and 



^ Sachs, Traiti de Botanique. p. 285. 



