HISTORY OF PILOBOLUS 23 



the sporangiophore of Pilobolus, when it is kept in a saturated 

 atmosphere, are formed by the active or the plasmolytic excretion 

 of water. As a matter of fact a drop of the fluid leaves a crystalline 



Fig. 12. — Pilobolus Kleinii. Sporangiophores in various 

 stages of development represented semi-diagrammati- 

 cally in one drawing : h, the substratum of horse dung ; 

 in a the stipe is elongating ; in b the sporangium is de- 

 velopmg terminally; in c each sporangiophore has 

 developed a large subsporangial swelling beneath the 

 sporangium, and the sporangium is about to be dis- 

 charged : in d the sporangium has been discharged and 

 only the collapsed stipe and subsporangial swelling remain 

 behind. The sporangiophores are bedecked with numer- 

 ous watery drops which glisten in the light like dew- 

 drops. Drawn by E. Boudier ; photographically copied 

 from Plate 582 of his Icones Mycologicae ; letters added 

 by the author. Magnification, 16. 



deposit when allowed to dry upon a cover-slip. It is therefore 

 possible that the excretion of water is plasmolytic in this case, for 

 any osmotic substance must tend to withdraw water from a fully 

 turgid cell with which it is in contact." 



