D. Keilin 
231 
V. PROBABLE MODE OF INFECTION. 
The escape of these spores probably results from the rupture of the spo¬ 
rangium along the clearly marked line of cleavage that runs along its convex 
surface. I was able to observe such rupture of the sporangium by compressing 
Fig. 7. Coelomomyces stegomyiae. A, section of the wall of sporangium: a., apertures; en., internal 
structureless membrane; ex., external thick perforated membrane; p., central protoplasmic 
content; B, section of an unripe sporangium; C, section of sporangium showing the beginning 
of the breaking up of its content into separate cells; D, sporangium with a thin wall and 
content divided into a great number of spherical cells, spr.; E, section of a sporangium showing 
the completely formed spores, spr.; F, spore (or probably a zoospore) from a sporangium 
similar to that represented in Fig. E; G, a small sporangium with spores, seen in toto the 
external layer having ruptured and the internal thin membrane bulging out from the slit. 
it between the slide and a coverglass. When the external wall of the sporangium 
is ruptured, the thin internal wall bulges out and by its rupture allows the 
spores to escape. It is possible that the protruded internal wall of the 
