N ales. 
147 
4 ju in diameter, but many of them have a diameter of 4*5 to 5 p. 
The nucleoli are about 1*9 to 2 /x in diameter. 
Soon after the nucleus has taken up its position near the apex 
of the basidium, it begins to divide, first of all into two, then into four. 
The division is an indirect one and takes place before the appearance 
of the sterigmata. Previously to the division, the nucleus elongates 
slightly in the direction of the long axis of the basidium ; its outline 
becomes somewhat irregular ; the threadlike network accumulates at 
the apex, and the nucleolus takes up its position at the opposite end 
of the nucleus. The nucleolus gradually disappears, and at the same 
time a group of deeply staining short threads or granules appears in 
place of the threadlike network at the upper end of the nucleus. 
The nuclear membrane now seems to disappear, but an irregular 
and somewhat clear space surrounds both the nucleolus and the 
deeply stained chromatic elements. These latter separate into two 
groups which pass to either side of the basidium. In this way two 
new nuclei are formed, which are small at first, but gradually increase 
in size, and have a structure similar to that 'of the parent nucleus. 
The two nucleoli appear to be formed from the chromatic elements. 
Each of the two daughter nuclei now elongates and divides in the 
same manner as the primary nucleus. The four nuclei thus formed 
have a structure similar to the parent nucleus, but are much smaller. 
The four nuclei now pass, previously to the development of the 
sterigmata, to the lower end of the Jbasidium, where they come into 
such close contact with each other as to appear as if fused together ; 
it is not quite certain whether fusion does or does not take place ; in 
any case the nuclei undergo certain changes resulting in the accumu- 
lation of a more or less irregular mass of chromatin on their walls. 
This chromatin presents the appearance of a very loose network 
surrounding the four nucleoli. 
While these changes are taking place, the four sterigmata appear at 
the apex of the basidium. At the apex of each sterigma a spore 
is produced, and protoplasm from the basidium passes into the spores. 
The nuclei at the base of the basidium now separate and pass 
to the apex. Each nucleus takes up a position at the base of one of 
the sterigmata, and this position is retained for some time. The pro- 
toplasm of the basidium passes into the spores which are increasing in 
size. Vacuoles appear in the protoplasm of the basidium, and finally 
nearly the whole of it is transferred to the spores. 
L 3 
