in the Hymenomycetes. 501 
to say definitely that the nucleolar substance is taken up in 
such a way, but it seems to me that this explanation is 
a legitimate one, and best fits the facts observed. 
The Nuclear Spindle. 
The formation of a nuclear spindle takes place soon after 
the disappearance of the nuclear membrane and the formation 
of the equatorial plate (Figs. 9-13 and 39-41). It is placed 
transversely in the basidium, and consists of a few very fine 
and delicate threads. These diverge only very slightly from 
one another, so that the spindle appears very narrow. It can 
be most easily observed in Agaricas muscarius , but is also 
distinctly visible in A. stercorarius . At each pole of the 
spindle, can be seen, in favourable specimens, especially in 
A. stercorarius , two very minute, deeply-stained granules 
(Figs. 9-12). These occupy a position similar to that of the 
centrosomes of the attractive spheres, which are to be found, 
as Guignard has shown, in the cells of the higher plants 1 , 
but no trace of the clear border with circular outline, or the 
radiating striae, described by this author, were to be seen. 
It is perhaps not advisable, therefore, at present to speak 
of these bodies definitely as centrosomes, but their presence 
here, taken in conjunction with Gjurasin’s discovery of radiating 
striae at the poles of the spindle in the ascus of Peziza , 
renders it probable that with improved methods of staining 
and observation, these bodies will be found to belong to 
definite attraction-spheres. 
Formation of Daughter-Nuclei. 
The chromatic elements now begin to divide into two 
groups which move towards the poles of the spindle. Pre- 
viously to the separation, a longitudinal splitting of the 
chromatic elements was not observed. This may have been 
due to their excessive smallness, which renders the deter- 
1 Sur l’existence des * spheres attractives’ dans les cellules vegetales — Compt. 
Rend. Acad, des Sci., 1891. Nouvelles etudes sur la Fecondation — Arm. des Sci., 
Bot., Ser. VII. tome 14, 1891. 
L 1 2 
