248 



BOTANY. 



consists of a rounded oosphere situated within a cavity the 

 oogonium ; it is developed from one of the cells (sometimes 



two) of the filament 

 by a condensing 

 and rounding off 

 of the protoplas- 

 mic contents; when 

 the oosphere is ful- 

 ly formed, an open- 

 ing is formed in 

 the oogonium-wall 

 for the ingress of 

 the spermatozoids 

 (A and B, Fig. 

 167). One or more 

 spermatozoids are 

 produced in each of 

 certain small cells 

 which are formed 

 from the large ones 

 by a process of 

 simple fission ; in 

 shape they resem- 

 ble the zoospores 

 mentioned above 

 that is, they are 

 oval and provided 

 with a crown of 



Pig. 167. A, middle part of a sexual filament of (Edo- vibratile cilia On 

 gonium oiliatum (Androgynia of Wood), with male cells . . ,, 



above at m ; og, oogonia (fertilized) ; m, dwarf male their Smaller CX- 



Z t 



plants attached to the side of the oogonia, the sperma- , ., / n 



tozoids already discharged, x 250. B, oogonium, og, tremity (JJ, 



T-V 



-Pig- 



at the moment of fertilization ; o. the oosphere ; e, the 



spermatozoid forcing its way into the oosphere ; m. the 



dwarf male plant. C, ripe oospore. I>, (fflogonium 



gemtlliparum (Pringsheimia of Wood), part of the male 



filament, with gpermatozoids, e, issuing from the cells. 



E, part of a branch of Xultxxshcete intermedia, with oogo- 



nia, the uppermost containing an oospore, the middle 



one with an oospore escaping, the lower empty, f, four . . . , , 



zoospores resulting from an oospore of Bulboc/iate. 6, a Splitting of the 



eoospore come to rest and germinating. After Prings- ,; ,, 



helm. wall of the mother- 



cell, they swim about vigorously, and eventually make their 

 way through the opening in the oogonium, and then bury 



TT-r>r> 

 upoi 



i-nfn flip 

 ill 



wliipVi i5 rpn- 



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possible by 



