

58 BOTANICAL GAZETTE [july 



zoospore has become permanently attached to a large one, the 

 latter continues to move about for a time before coming to rest. 

 An amoeboid form is finally assumed, and disintegration soon 

 follows. 



Fusion of zoospores has been reported but rarely in the Chy- 

 tridiaceae. Probably this is because of the very limited obser- 

 vations upon the motile stages. Fisch (14) observed and figured 

 a fusion of zoospores for Reesia amoeboides. Dangeard (9) noted 

 an apparent fusion in Sphaerita endogena. Kusano observed a 

 clear case of fusion in Olpidium, the fusing cells being similar in 

 size. The observations of Sorokin (33) upon Tetrachytrium, of 

 Atkinson (2) upon Lagenidium, and of von Lagerheim (18) upon 

 Rhodochytrium should also be mentioned in this connection. 



The motile spores were fixed and stained upon the cover slip 

 by the use of osmic acid and gentian violet. Each spore was found 

 to have a short cilium as well as the long one visible in the water 

 (fig. 28). The motion of the zoospore, after the long cilium be- 

 comes passive, is probably due to the activity of the shorter cilium. 

 It seems possible that the uniciliate condition is not so common 

 among the Chytridiaceae as has been thought. Care in staining 

 and observation is necessary for a successful determination of the 

 number of cilia. Cornu (7) found only one cilium borne by the 

 motile spore of Olpidiopsis. Fischer (15) later found two, which 

 observation was confirmed by Barrett (4) . Cilia of unequal length 

 on the same zoospore have been reported and illustrated for various 

 members of the family, as for example Sphaerita endogena (9). 



The cilia of the motile cells of the organism under consideration 

 are attached at the same end of the zoospore to what seems to 

 be a platelike thickening of the membrane. The manner of attach- 

 ment is much more clearly seen in the larger zoospores (figs. 31,32). 

 The oil vacuole is near the place of attachment of the cilia (fig. 40). 

 The nucleus lies back of the vacuole, imbedded in the cyto- 

 plasm. From the cilia to the nucleus there is a connecting, cone- 

 shaped, apparently fibrous structure, which extends through the 

 vacuole (figs. 31, 32). Fig. 25 shows a general similarity to the 

 zoospore structure described by LoEW r ENTHAL (20) for Olpidium, 

 and figured by Nowakowski (23) for Polyphagus Englenae. 





















