33 ° Wager . — On the Presence of 
the nuclei clearly stained whilst the protoplasm remains un- 
stained. These nuclei pass into the basidia, but at first the 
basidia are quite destitute of nuclei and contain two or three 
vacuoles (Fig. 2). The presence of vacuoles, as well as the 
size of the basidium, afford good indications of its age, so that 
it is quite easy, in looking over large numbers of sections, 
to arrive at a perfectly safe estimate as to the stage which the 
basidium has reached in its development. By working in this 
way I have been able to make out certain facts which indicate, 
as before mentioned, the nuclear origin of the centrospheres. 
The quite young basidium does not contain nuclei (Fig. 2), 
but it does not remain long in this condition. Very soon 
after its formation nuclei pass into it from the hypha, upon 
which it is borne. The number of nuclei which pass in at 
first is two, and I have never seen a basidium with more than 
two nuclei at this stage (Fig. 3), but more than two pass in 
ultimately. These nuclei are precisely similar in structure to 
those found ordinarily in the hyphae, except that they may 
be a little larger, and a trifle more distinct. The chromatic 
elements inside them stain deep bright red, so that they are 
easily seen. In basidia, at a slightly later stage of develop- 
ment, the two nuclei are found to have increased in size, and 
a nucleolus just begins to be visible. The chromatic elements 
still stain bright red, but the nucleolus stains somewhat blue 
and is very indistinct. As the basidia develop, these nuclei 
become larger and the network becomes more distinctly 
visible ; the nucleolus also increases in size and can now be 
very easily seen. At this stage the nucleolus stains bluish 
red, and the chromatin-network is still red, but the colour is 
not so bright as before, and there is perhaps a tinge of blue 
to be made out in it. As the nucleus becomes older the 
chromatin -network tends to become more blue, and the 
nucleolus tends to take up more of the red stain (Fig. 4). 
It is interesting to compare these developmental changes 
with those which take place later in the gradual formation of 
the daughter-nuclei, after division, in the basidium, as they 
are almost precisely similar, and give indications of one of 
