152 
ON THE PILOBOLID.E. 
terminal vesicle are almost completely slmt off from com¬ 
munication with the mycelium (Fig. 3). At any rate this 
vesicle, which is the beginning of the future sporangium, 
increases very little in size after its first formation, and that 
little mainly by the upward growth of the septum in a 
conico-convex form in its interior. We shall see afterwards 
another reason for believing that very little communication 
takes place between the stem and the sporange after the 
separation of the latter. The fungus now presents the 
appearance shown in Fig. 3, and may be compared to a pin, 
the head being of a brilliant opaque golden yellow and the 
stem of a translucent watery or almost milk-and-watery colour. 
The stem may continue to increase in length by intercalary 
growth to a certain small extent, after the separation of the 
sporangium; the average height of the mature fungus is 
slightly greater than when the sporange is first outlined. 
cl. —The Spokange. 
As soon as the sporange is completely shut off from the 
stem, changes begin in both parts and proceed simultaneously. 
We will first notice the changes in the sporange. Hitherto 
its bounding membrane has been thin, and permitted the 
yellow granular contents to be seen through ; but now it 
begins to grow thicker and darker in colour, a process which 
commences at the top and gradually spreads downwards on 
all sides towards its junction with the stem, but, stopping a 
little short of this, it leaves a narrow transparent zone belting 
the sporange immediately beneath the equator, through which 
the contents are still clearly visible (Fig. 8). During this 
thickening process the sporange undergoes changes of colour 
which result from the superposition of the blue-black or 
brown-black of the cuticle upon the yellow, almost orange, of 
the contents. After passing through various shades of olive 
and smoky brown, it finally becomes opaque and, by reflected 
light, black. When complete it is adorned with little pro¬ 
jecting warts, which impart a somewhat rough aspect under a 
high power, and is encrusted with numerous fine acicular 
crystals of oxalate of lime. It is also, in F. crystallimis , 
occasionally marked with paler hexagonal reticulations, but 
the occurrence of these seems to be somewhat fortuitous. 
The finished “ cap ” is rather tough and cartilaginous in 
texture, though on account of its hollow form it is easily 
split by pressure. At first, after the formation of the septum, 
the indurated membrane of the higher portion of the imma¬ 
ture sporange shades off gradually, at its lower edge, into the 
hyaline zone, and, if at this stage the sporange is submitted 
