1 88 Barker . — The Morphology and Development of 
eventually produce small spherical eight-spored asci. The 
asci are very thin-walled, and soon break down, liberating the 
spores into the cavity of the nest, and at the same time the 
ascogenous hyphae also degenerate, so that the ripe ascocarp 
is filled with a large number of spores lying free in its interior 
amid a mass of mucilaginous substance produced by the 
degeneration of the other structures. During this time the 
central cell has undergone many changes. The nest of asco- 
genous hyphae in its growth displaces it and causes a con- 
siderable alteration in its shape. As the nest increases in size, 
it penetrates towards the centre of the central cell, which, in 
its growth, closes over it, so as to make it appear as if it were 
an internal development. Eventually the central cell ceases 
to grow, but the ascogenous hyphae continue to enlarge the 
size of the nest until asci are formed, thus causing the sur- 
rounding wall, which consists of the hollowed-out central cell, 
to become stretched and therefore thinner. The contents 
gradually disappear and the walls become cutinized, so that 
finally nothing remains of the central cell but its walls, which 
form a complete envelope around the asci and ascogenous 
hyphae. At first spherical, it thus gradually becomes changed 
in shape to a hollow sphere by the formation of a depression 
at one point, which extends by degrees to its centre, the 
mouth of the depression being roofed over by its growth. The 
depression itself is caused by the formation of ascogenous 
hyphae and its enlargement is due to the growth of these 
structures. The ripe ascocarp is thus a simple sporangium-like 
structure — a pseudo-sporangium. The complicated interme- 
diate stages of its formation are due entirely to the curious 
behaviour of the central cell in growing around and thus 
enclosing the earliest formed ascogenous hyphae. It is thus 
in reality very simple in origin. 
No other satisfactory interpretation of the structures ob- 
served during the development of the ascocarp seems possible. 
The ascogenous hyphae must arise from the central cell, 
since no trace of a possible origin from the investing hyphae 
has been seen. In specimens of fixed material mounted in 
