OF MICRO- OR GANISMS. 8 5 



contracts, and presents at its free end a slight pro- 

 tuberance, which allows the zoospore to fix itself upon 

 an immobile point; as to the rear flagellum, it slips 

 back upon the posterior part of the body which it 

 encompasses, and finally disappears. — When the fe- 

 male zoospore has become motionless, the male zoo- 

 spores, hitherto indifferent, are seen to make towards 

 it and to surround it in a half-circle; the number of 

 zoospores that thus meet, is quite considerable; it 

 frequently exceeds a hundred 

 (■fig. 10). They let their second 

 flagellum float loosely behind 

 them, while they all direct their 

 anterior filament towards the fe- 

 male cellule; this filament they 

 draw back and forth over the 

 Fig. /o.-sexuai reproduc- body of the female cellule; they 



tion of the Eciocarpus silicu- r -i. l a ^r i 1 



idsus. Female zoBspore sur- perform upon it real acts ot teel- 



roundedbymalezofispores. j^^^ ^^^ ^^-^^^ ^f ^j^j^j^ j^ ^^j, 



dently to provoke in the female zoospore a genital ex- 

 citation, as what follows will prove. It happens at 

 times that several of the male zoospores quit the 

 ranks and make off; they are immediately replaced by 



others who employ 

 their filaments in a 

 ^^ like manner, to stroke 

 %■) the female. Finallj^, 

 upon the expiration 

 of a certain time, 



Fi>. If. — Sexual reproduction of the £cto- One of the ZOOSpOreS 



t:arpus siliculosiis. Successive stages of the l„_,,„„ i.l,„ v,„]f ^\y 



copulation of a female zoospore with one of the icdvca Liic iictii k^ii. 



male zoospores. ^jg ^^^ approaches 



the female. The two zoospores unite; after having 

 presented the series of changes marked in the figure, — 



