432 
Notes . 
so obvious as those of Aneura or, especially, of Fossombronia , at the 
corresponding stage. One reason for this is perhaps to be sought 
for in the shape of the spore-mother-cell of Pellia. The four lobes 
are much elongated tetrahedrally, and hence only one of the four 
spindle-rays can possibly, even in the most favourable case, be cut 
radially, i.e. in such a manner that it can be followed out, in the 
same section, to the distal end. The rays in the three remaining 
lobes will obviously present a more or less truncated appearance, 
such as is actually represented in the Figures 8 and 9 in Plate X. 
A further obstacle in the way of the recognition of centrospheres lies 
in the extreme difficulty of properly fixing the cell-contents of the spore- 
mother-cell of Pellia at this stage, and in this respect again it compares 
unfavourably with the other examples above mentioned. An inspection 
of some of Prof. Davis' figures, notably 1, 2, and 7, sufficiently proves 
that he has himself experienced this difficulty. 
When discussing the significance of the quadripolar spindles, and 
their relation with the achromatic figures commonly met with in 
ordinary cells, I expressly endeavoured to guard myself against the 
possible misconstruction of having attributed them to any circum- 
stances other than those involved in the unusual form of the cells 
concerned. Indeed, the chief interest for me in these spindles lay 
precisely in the possibility of so correlating them. And thus it 
appeared that the extreme diversity met with in the different genera 
of the Hepaticae investigated by me was susceptible of an explanation 
sufficiently general to cover them all (vol. ix, p. 1 50). 
But notwithstanding the evidence furnished by his own figures, 
Prof. Davis seeks to explain away the existence of the quadripolar 
spindles by calling them a condition of prophase only, and by imply- 
ing that the existence of a kinoplasmic weft enveloping the nucleus 
is sufficient to disprove their existence, or at any rate to rob them 
of all importance. Such a priori arguments appear to me to be 
futile, even were they not sufficiently answered by actual observation 
of the very definite structures themselves. Quite apart from the 
existence of centrospheres, it is impossible to disregard the evidence 
presented by the character of the nucleus and the kinoplasm. Thus 
a nucleus is shown in Fig. 5, distorted and pulled out tetrahedrally, 
and the proximal parts of the spindle arms are also represented. 
The suggestion is put forward that the ‘ accumulations of kinoplasm 
most naturally then take up positions of least resistance, and extend 
