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related to the Flagellata, while the Chytridineae: with one flagellum may 

 be derived from the Monadinae. It is not distinctly explained by Vuille- 

 min, where such forms as Pseudolpidium with two flagella must be placed, 

 but he writes on this form and another „ces derniers genres n'ont de 

 commun avec les Chytridinees que leur grande simplicite", an opinion 

 indicating a relationship between the Pseudolpidium and the other two- 

 flagellated Phycomycetes. 



The distinction between one- and two-flagellated (Ihytridinese and 

 other Phycomycetes has before Vuillemin been indicated by Lotsy^). I 

 cannot see the great importance of the number of flagella, that it is 

 necessary to consider the Chytridineae with one flagellum as modified 

 Monadinae and the other as modified Algae or higher Phycomycetes; the 

 two groups are in morphological and other respects not much differing 

 from each other. Admitting that the Monoblepharis is related to Myrioble- 

 pharis and Diblepharis, I am sceptical to the eminent systematical impor- 

 tance of the number of the flagella. I admit that this difference indicates 

 two series of Phycomycetes, but I must consider these as closely related 

 to each other having related ancestors. 



The cardinal point as to the relationship between the uniflagellated 

 Chytridineae and the Monadinae is the single flagellum; in other respects 

 these two groups are different. I shall not enter into details as to the 

 comparison of the Chytridineae and the Monadinae; I shall only set off 

 some points particularly with regard to the mycelium which is not found 

 in the Monadinae, but which is present, at all events as traces, in the 

 Chytridineae. 



It is a matter of fact that the zoospore in the uniflagellated Chytri- 

 dineae as in the two-flagellated ones often is found forming a little my- 

 celium for example in Phlyctochytrium and in Diplophlyctis. The forma- 

 tion of channels for the zoospores can be looked upon as a trace of a 

 mycelium. A form as Zygorhizidium forms a little mycelium in the sexual 

 tubes. Further there is hardly so deep a cleft between rhizoids and 

 mycelium. The transition between these parts is particularly insensible in 

 Siphonaria variabilis. The manner of entrance of the zoospore leaving a 

 „Cystenhaut", in connection with the above named tendency to forma- 

 tion of mycelium, rather implies a relationship to myceliated ancestors 

 than to the Monadinae where mycelium is unknown. The power of the 

 zoospore forming a mycelial membrane is a very important matter, which, 

 in my opinion, mainly separates the Monadinae from the Chytridineae. 



Pseudolpidium is doubtless a reduced Lagenidiacean resembling a 

 unicellular form of Myzocytium for example. Lagenidiaceae are further 



^) Vortrage fiber botanische Stammesgeschichte, Jena 1907. 



