OBSEEVATIONS ON THE GENUS PYTHIUM. 505 



calary growth behind the apex appeared to have occurred in 

 the interval (c, d, and f), but I coiihl not be sure of this since 

 the change might be due to a straightening out of the tube in 

 that region. The protdj)lasm was by this time passing for- 

 ward towards the apical portion, and only a few granules 

 remained in the oosphere and proximal part of the hypha. 

 Once inside the dead seedlings the fungus extends in the 

 manner already described, and sooner or later begins to form 

 zoosporangia. 



These arise as projecting hyphse, usually vertiral or nearly 

 so from the epidermis of the seedling, and they differ in several 

 important respects from those already described. In fig. 24 

 are drawings showing the various stages witnessed in the for- 

 mation of the complete sporangium. As seen at first, it was 

 a simple perpendicular branch from the mycelium, filled with 

 densely granular protoplasm and with a rounded apex; at 

 11.8 o'clock the slightly swollen rounded apex was extremely 

 bright, and appeared capped by a hyaline dome, due to some 

 alteration in the cellulose. During the next ten minutes this 

 cap of diffluent cellulose commenced to swell up gradually and 

 at 11.20 presented the appearance seen in the figure. Almost 

 immediately after this, the finely granular contents streamed 

 suddenly forward into the centre of a gelatinous vesicle formed 

 by the bulging out of the diffluent swollen cap, this streaming 

 resembled very much the rush of en do pi asm often noticed in 

 the prolusion of a large pseudopodium by a vigorous amoeba; 

 the flow of granules was most rapid in the axial portion, and 

 the last particles followed more slowly. The third figure repre- 

 sents the moment before this flow ; in the last of the series are 

 depicted the appearances at the instant of its occurrence. In 

 this example the succeeding stages could not be drawn rapidly 

 enough ; they were the same as shown in figs. 25 and 26, and 

 a good idea of the rapidity of this process is gained by com- 

 j)aring the time-records made ; the last two stages of fig. 2 a were 

 drawn at 11.23; at 11.25, the whole mass of protoplasm had 

 passed out into the mucous globe, and was already becoming 

 divided up into zoospores (fig. 26 h). At 11.32 these zoo- 



