418 H. MARSHALL WARD. 



in the drawing), and one at the base. The drawing was made 

 at the higher focus. 



Four minutes after the drawing of k was completed the 

 papilla at the apex gave way, and the zoospores glided out as 

 shown at I. They appeared to be quite passive, as if being 

 pushed out from behind. Special attention was paid to the 

 fact that they were squeezed through the narrow aperture. 

 On reaching the exterior the zoospores did not immediately 

 move away, but remained some seconds, as if hesitating, as it 

 were ; possibly the shock of meeting the water outside affected 

 them. Two of the zoospores remained united for several 

 seconds, presenting a superticial resemblance to conjugating 

 amoebse ; after slight amoeboid writhings they separated, but did 

 not move out of the field. The zoospore [n) moved away briskly, 

 but came to rest in less than a minute, and close to the now 

 empty conidium, or zoosporaugium, as it may be called. 



The movements and changes of the other zoospores could 

 not be followed, as attention was devoted to the specimen n, 

 the further fate of which was followed, and noted as accurately 

 as possible (see o to z). Owing to its movements being nearly 

 circular, and its coming to rest close to the empty zoosporan- 

 gium, it was easy to see the two cilia and two vacuoles (o) as tiie 

 movements ceased. The zoospore then became rounded oflF and 

 seemed to throw off its cilia — at least I saw one detached (r, s), 

 and lost sight of the other one. The two vacuoles became 

 smaller and soon disappeared, as if the zoospore in diminishing 

 its volume squeezed out water. As far as it was possible to 

 judge, these processes occupied one minute, and the zoospore 

 had then come to rest as a spherical mass (s), which soon 

 clothed itself with a recognisable but thin membrane. 



It should be pointed out that the zoospore here followed 

 moved for a very short time compared with others. I have 

 frequently seen the zoospores still active twenty minutes or 

 more after emergence, and they are said to move even longer. 

 At the same time they often come to rest in from one to five 

 minutes, and sometimes only give one little flirt and then come 

 to rest. 



