Centro spheres in Pellia epiphylla , Nees. 2 2 1- 
cells, nor have we been able to ascertain the existence of any 
definite particle within them which would indicate the presence 
of a centrosome ; it is true that in some instances such a point 
could be distinguished, but we do not attach much importance 
to it, since in the great majority of centrospheres it completely 
eluded recognition. And, although the radiation in the cyto- 
plasm may readily be traced into the protoplasmic corpuscle, 
we prefer for the present, at any rate, to term this a centro- 
sphere rather than a centrosome, since it appears probable 
that the corpuscle is really equivalent to something more than 
the centrosome alone. 
The cytoplasmic radiations are exceedingly clear in this 
plant, and especially well seen when regarded from above, 
i. e. in the direction of the polar axis, and they are then seen 
to spread out in a star-like manner from a common centre 
(PL XIV, Fig. 5). 
Presently the centrospheres assume such a relation to the 
nucleus that one can hardly resist interpreting it as a pulling 
strain. The nucleus becomes more and more drawn out into 
an elliptical shape, and at the somewhat pointed ends the 
centrospheres are respectively situated (PL XIV, Fig. 2). The 
chromatin now becomes distributed in the form of a narrow 
equatorial band lying just within the nuclear membrane which 
still persists, and indeed, in this equatorial region, exhibits, 
if possible, a sharper outline than before. The chromatin 
gradually becomes more definitely fibrillar, and finally appears 
in the form of eight chromosomes, which can easily be counted 
when the equatorial nuclear plate is formed. Meanwhile the 
rest of the nucleus is entirely free from staining-substance, 
and its ends become more and more drawn out, whilst its 
wall becomes pari passu, much thinner, except just outside 
the chromatic band mentioned above. The cytoplasmic 
radiations increase in number and distinctness, and extend 
over the attenuated nuclear wall. Concomitantly with the 
final disappearance of the latter, the achromatic spindle is 
differentiated, and rapidly becomes very prominent, owing to 
its growing capacity for taking stains. It is hardly possible, 
