ON SAPROLEGNIJ;. 289 



abbreviated; it consists merely in complete isolation. The 

 resting globules germinate in situ in the zoosporangium. 



That we are brought face to face here with a profound 

 problem in its simpler forms is obvious. Perhaps the only 

 light it afFonls us as yet is the suggestion once more of the 

 exceedingly complex nature of the changes proceeding in the 

 simplest piece of protoplasm. It appears somewhat significant 

 that the second form of zoospore — the reniform one with lateral 

 cilia — is that most constant. This is the only form in the 

 nearest fungoid allies of the Saproleginse, and must probably 

 be regarded as the most ancestral form ; nevertheless it is 

 not easy to suggest how or why the other zoospore was ac- 

 quired. 



With respect to the "sexual reproductive organs" of this 

 groupj much has been written and many theories advanced since 

 Alexander Brown and Pringsheim first described them and 

 their relations. The antheridia were first believed to pour 

 granular matter into the oogonium amongst the ova (oo- 

 spheres). Then Pringsheim discovered that the oospheres in 

 certain cases become normal oospores without the appearance 

 of antheridia. Certain small antherozoid-like bodies were 

 then believed to be set free and find their way into the 

 oogonia amongst the oospheres. Meanwhile other observers 

 denied that the "antheridia" either fojmed antherozoids, 

 or that the tubes sent into the oogonium emptied anything 

 into its cavity. 



The discussion seems to have been somewhat in this state 

 when Cornu/ in 1872, described the process of fertilisation, 

 &c., as consisting neither in the formation and entry ot 

 antherozoids, nor the emptying of granules between the 

 oospheres, &c., but in the passage of protoplasmic contents 

 from the antheridium through the fertilising tube and 

 into the substance of the oospheres. This view has been 

 accepted somewhat widely. 



De Bary seems to have maintained for some years that, in 

 some cases at least, no passage of material takes place through 

 1 ' Ann. d. Sc. Nat./ 5th sen, t. xv. 



