300 Allen . — The Early Stages of Sphidle- Formation 
according to Stevens (’98), in the pollen-mother-cell of As- 
clepias ; the origin of the fibres, as described by Murrill (’00), 
in the central cell of the archegonium of Tsuga , from two 
unequal polar kinoplasmic masses ; and the instance described 
by Miss Ferguson (’01) in the division of the generative 
nucleus of Pinus , where the spindle arises as a cone of fibres 
from a single cytoplasmic condensation below the nucleus, 
the latter lying close to the upper boundary of the cell. But 
such cases seem to be quite unusual, and it may be that 
further investigation will harmonize these with what are 
apparently more typical instances of spindle-formation. 
I have spoken of the cytoplasm in the early stages as 
composed apparently of a kinoplasmic network with empty 
meshes. The spaces between the fibres are of course filled, 
as the turgor of the cell shows, and it seems improbable that 
they are occupied only by a lifeless cell-sap. In later stages 
there is plainly an orange-staining inter-fibrous substance, 
granular rather than alveolar in structure, but in the earliest 
preparations I have not succeeded, by any variation of the 
staining process, in finding a trace of colour in the cytoplasm 
outside of the fibres. I have also been convinced from 
a careful study of Flemming and Vom Rath preparations that 
the fibrous appearance is not a precipitation result. Still 
earlier preparations of the developing male cones will be 
necessary to throw further light upon the cytoplasmic structures. 
As has been said, the great preponderance of evidence is 
opposed to the existence of centrosomes in the higher plants ; 
and conditions in the Larch seem to justify us in saying that 
here the possibility of a centrosome, in the sense of a directive 
organ, is excluded. Not only is no such body to be seen 
at any stage, but, if my observations are at all correct, there 
is no room to assume its operation. The fibres change their 
position without reference to any centre or to any definite 
number of centres. If centrosomes determine the radial 
arrangement, for example, we must imagine either as many 
centrosomes as there are radial fibres, or else a single centro- 
some somewhere within the nucleus ; and when the multipolar 
