Some recent work on the cytology of fungus reproduction, II 
229 
Vuillemin regarded the process as simply a phenomenon of budding 
and Fischer considered the attached cells as „Sammelzellen“. The non¬ 
sexuality of the organs has been shown by Maire and Tison (see below) 
and by the present study. „Wenn hier Sexualität vorhanden ist, so muß 
sie an einem ganz anderen Ort gesucht werden, nämlich entweder bei 
den Schwärmsporen, deren Copulation mir nicht unmöglich erscheint“. 
The young stages of the parasite completely fill the host cell with a 
tangled mass of extremely thin hyphae. In the capitate swellings at the 
ends of the hyphae arise the young spores which have at first a single 
large nucleus possessing a prominent nucleolus and some linin threads. 
As growth proceeds nuclear division occurs. The nuclei in the following 
stage are smaller but very numerous. In the further developed cells the 
nuclei are few and large. When a certain size is reached zoospore for¬ 
mation commences. True mitosis was never observed but nuclear gem¬ 
mation and heteroschizis were not at all infrequent. Budding was found 
chiefly in the stages preceding zoospore formation. The zoospores are 
formed independently of the nuclei. Bally divides the Chytridiales into 
two groups one where the uninucleate stage continues until the nuclear 
divisions previous to zoospore formation (Synchytrium , Chrysophlyctis), 
and the other where nuclear division goes on together with the growth 
of the cell (Olpidium, Cladochytrium). He follows Pavillard in belie¬ 
ving that the Synchytriaceae show great cytological similarities with the 
Sporozoa and were probably derived from them. 
Previous to the appearance of Bally’s paper, Maire and Tison 
(1911) published a short account of the cytology of the Cladochydriaceae 
(Cladochytrium , Physoderma and Urophlyctis). The “vésicule collective 1 ' 
of Vuillemin is found at the interior of the host cell near the point 
of infection. This gives rise to a certain number of new pedicellate 
vesicles by budding and the secondary vesicles bud in their turn in the 
same way. At each budding the lower vesicle empties itself into the 
upper one. Finally the terminal swelling produces only a single bud 
with a short pedicel. The bud swells and forms the “chronisporocyste’* which, 
like the vesicles, is plurinucleate. There is no trace of karyogamy at 
any stage seen. The nuclei vary much in form and dimension. Typi¬ 
cally formed of a nuclear membrane, a lateral karyosome and a loose 
achromatic network they appear to multiply solely by amitosis. In the 
developing chronisporocyst certain nuclei swell and their karyosome 
vacuolates giving rise to large masses of a substance which accumulates 
in the centre of the cell. Around this substance which appears to play 
the rôle of reserve material, some nuclei are found which remain intact. 
In Physoderma Urgineae , the fungus presents itself in the form 
of small uninucleate amoeboid masses. These naked cells multiply by 
simple divsion but do not remain joined. They then become multinucleate, 
surround themselves by a membrane, and become chronisporocysts. “La 
formation des chronisporocystes représente ici un simple enkystement se 
produisant à la suite d’une schizogonie. ... Le développement endo- 
phytique est la même dans le Physoderma GehrhartiiC From the 
researches of Lüdi (1901) it is known that Cladochytrium Menyanthes 
forms its chronisporocysts in a manner analogous to Urophlyctis . The 
Cladochytriaceae “sont donc asexués au moins pendant leur vie endo- 
phytique’’. The authors consider the group to be fairly homogeneous 
