THE SOUND MADE BY FUNGUS GUNS 327 



be heard when a Pilobolus gun goes off : (1) the sound of the ex- 

 ploding gun and (2) the sound of the projectile striking some object. 

 W. B. Grove, ^ in 1884, was the first to hear the sound emitted by 

 the gun, and in 1909 I confirmed his observations. ^ More recently, 

 in my laboratory, I listened to the shooting away of the sporangia 

 of Pilobolus longipes and, each time a gun went off, I distinctly 

 heard a minute snap. I asked my colleague Mr. C. W. Lowe and 

 my laboratory attendant to listen also, and they both declared that 



Fig. 1G2. — Acetabnla vulgaris. Anton de Bary records (1884) that lie 

 lieard a very perceptible hissing sound when large specimens of 

 tliis fungus puffed vigorously. Photographed by A. E. Peck at 

 Scarborougli, Englan(l. Natiu-al size. 



the sound of each explosion was unmistakable. In Volume I of 

 this work, I described a simple experiment which enabled a listener 

 to hear the striking of a Piloljolus projectile on a drum when he 

 was 21 feet away from the jilace of impact.^ 



Type III : Ascobolus. — In a fruit-body of Ascobolus hnmersus 

 (Vol. I, Fig. 81, p. 252) about half a dozen asci come to maturity 

 and explode every day about noon. The asci and ascospores are 



1 W. B. Grove, " Monograpli of the Pilobolidae," The MidUtnd Naluralist, 

 Birmingham, England, 1884, p. IT). 



2 These Researches, Vol. I, 1909, p. 259. ^ Ibid., pp. 259-200. 



