PLATE ii 
Progressive stages in the emergence of zoospores of Phyiophthora parasitica var. rhet t 
as shown by reproductions from a motion-picture film. 
Strip B follows A immediately on the film, and shows the rapid bursting outward of 
the papilla. The spot just in front of the sporangium is a zoospore from another 
sporangium. It has come to rest in a very unsatisfactory position. The glow of light 
just at the opening of the sporangium is another unsatisfactory feature which could 
probably be eliminated with more experience. 
Strips C to G were taken from widely separated intervals in the film, and show 
subsequent stages in the escape of zoospores. 
