OOMYCETES 



61 



Unfortunately in the aquatic Chytridiales, no studies of this sort 

 have been carefully conducted, but the conjecture of Scherffel, that an 

 entirely new point of view will be found, seems to be entirely justified. 



In Myzocytium proliferum on Zygnemaceae and M . vermicolum on 

 anguillules (Zopf, 1885; Dangeard, 1906), the zoospores are slightly 

 reniform and possess two lateral flagella. During their swarm period 

 they undergo amoeboid alterations of form. They then come to rest, 



Fig. 36. — Myzocytium vermicolum. 1. Worm with two specimens of parasite. 2. Cell 

 filament with two antheridia in the middle and an oogonium at each end. 3, 4. Antheridia 

 and oogonia. 5 to 8. Development of oospores. 9. Individual oospore in worm. {After 

 Dangeard, 1906.) 



surround themselves with membrane, force a germ tube into the host 

 cell and there mature to a thick, cellular multinucleate mycelium. At 

 the beginning of the formation of the fructification, the whole mycelium 

 is divided by septa into multinucleate members, each of which becomes a 

 zoosporangium (Fig. 36, 1). The protoplasm collects at the walls and 

 splits into uninucleate zoospore initials which pass singly out through 

 an emission collar and assemble at its mouth in a sac. Soon the flagella 

 are visible, the sac bursts, and the zoospores swarm. Zoospores which 



