218 
ON THE PILOBOLID.®. 
less. I have mentioned how frequently one or two “dew- 
drops” are found to occupy the angle between the swelling 
and the sporangium, and it is doubtless by this means that 
the dissolution of the diffluent zone is effected in a state of 
nature. We can often meet with the sporangia in this 
condition; it is then easily seen that the spores are not 
enclosed as they were before, except by the gelatinous 
substance. The black cap now lies loosely perched on the 
top of the spore-mass, and can be lifted off with the point of 
a needle, like a glove drawn off a finger. It frequently 
becomes puckered round the free edge and assumes a more or 
less angular outline (Fig. 5). When the ripe sporange is 
placed on a slide with abundance of water, the gelatinous 
substance swells up more than in the natural state, protruding 
beyond the cap in a characteristic manner, as shown in Fig. 5. 
k . —Projection of the Sporange. 
The sporange has now dehisced, and the spores may 
escape by degrees. But in order to secure their wider 
dissemination the sporange is usually projected to a distance 
with considerable force. This projection may take place 
before, but usually follows after the dehiscence. The con¬ 
tinued upward movement of fluid and protoplasm into the 
swelling of the stem, which was the cause of its formation, 
at last produces so great a tension of the walls that they 
give way at the point of greatest strain. It is easy to see 
that this will be along the circle of insertion of the columella 
or thereabouts. Just below this the rupture takes place; 
the walls of the swelling contract slightly, the tension being 
relaxed ; the contained fluid is spirted out, bearing with it 
the columella and the sporangium seated thereon. The 
movement is accompanied by a faint but distinctly audible 
“ puff,” like the sound of a minute pop-gun. The distance 
to which the sporange may be thrown varies according to 
circumstances from a few inches to several feet. If the 
Pilobolus be grown beneath a bell-glass the interior surface 
of the glass will be covered with the sporangia. Coemans 
records that they can be projected to a height of over three 
feet.* I have myself grown P. ceclipus beneath a glass shade, 
twelve inches high, and found sporangia adhering to it on all 
sides to the very top. 
Once while I was examining a tuft with a lens I heard a 
faint sound proceeding from another tuft six inches off, and 
at the same instant felt myself struck near the middle of the 
* Monogr., p. 39. 
