618 Buller .— The Function and Fate of the 
like a flask in function, that the wall closing the end of the neck acts 
as a stopper which drops out when the cystidium is ripe, and that through 
the neck the cystidium contents escape. His supposed discoveries that the 
cystidia produce spermatozoa 1 and fall from the gills with the spores 2 were 
simply further errors suggested by his imagination, and involved with his 
fanciful theory that the cystidia are antheridia, and that their spermatozoa 
fertilize the spores, which he regarded as female gametes. The reason why 
the base of a cystidium is narrowed is readily understood, when one 
remembers that it is necessary for the developing cystidium to retain 
its connexion with the small subhymenial cells. The general shape of 
a cystidium is very much like that of a prop, such as one sees used for pre¬ 
venting the collapse of the sides of deep trenches made in the ground. The 
narrowed end at the base and the blunt rounded end at the apex are well 
suited to prevent the cystidia from being pushed into the hymenium of 
either gill by lateral pressure. 
The cystidia are some of the largest cells found in connexion with 
fungi; they are 0*12 to 0-17 mm. long, and 0-02 to 0-03 mm. wide. Illus¬ 
trations showing their variations in shape and size are given in PI. L, Figs. 9, 
10, and 11. When a cystidium has become mature, it contains a very large 
central vacuole, and its protoplasm, except for a slight accumulation at each 
end of the cell, is reduced to a thin lining layer (PI. LI, Fig. 12). Owing to 
the limited time during which the living material was available, I was un¬ 
fortunately prevented from investigating the nature of the cell-sap. 
The distribution of the cystidia over the gills is fairly uniform (PI. L, 
Fig. 6). It was estimated that about 75 to 100 are situated on each square 
millimetre of gill-surface. The cystidia are sufficiently numerous to make it 
impossible for the gills to sag laterally, so that they should come to touch 
one another with their general surfaces. 
The gill-edges are not thickened, and in this are unlike those of 
Coprinus comatus . They are provided with cystidia which before the 
expansion of the pileus abut upon the stipe (PI. L, Figs. 5 and 6). 
The basidia are of the usual Coprinus pattern (PI. L, Figs. 8 and 11). 
They project considerably beyond the paraphyses, and are inserted in the 
hymenium by narrowed bases. The spores are oval in shape, and very dark 
brown in colour. The mode in which the basidia are spaced, and the 
manner in which the spores are situated on the sterigmata, are shown 
in PI. L, Figs. 6 and 11. 
The cells composing the young hymenium are fairly uniform in size, 
and more or less club-shaped. However, as differentiation proceeds, those 
cells which are to become basidia elongate in the direction of their long 
1 W. Smith, Reproduction in Coprimes radiatus. Greviliea, vol. iv, 1875. 
2 W. Smith, Ibid., p. 60. ‘ The spores naturally fall to the earth, and with them the cystidia, 
and it is upon the moist earth that fertilization is generally carried out.’ 
