500 Farmer . — On Spore- Formation and 
oil globules. At present, however, this is the only liverwort 
allied (almost certainly) with Marchantia in which I have 
observed any sign of a quadripolar spindle. 
Seapania undulata. 
The cells in Seapania after the last archesporial division 
become loosened from each other, and each one grows to 
a considerably increased size. As this increase becomes 
apparent, it is seen that the growth is not uniform, but that 
it is more active in four equidistantly-placed regions, and thus 
the cell as a whole assumes the four-lobed shape which is 
so characteristic of perhaps all the Jungermannia series of 
hepatics. The nucleus is situated in the centre of the cell, 
and consequently at the junction of the cavities formed by 
the four pouch-like outgrowths. As the spore-mother-cell 
approximates to its final size, the nucleus alters its appear- 
ance. During the earlier period, it is a rather diminutive 
spherical object, containing a small but readily stainable 
nucleolus. The extra-nucleolar portion, however, hardly 
stains at all. and it is difficult to make out any structure 
within it. But on passing out of the period of repose, the 
extra-nucleolar part becomes granular, and the linin frame- 
work is easily discernible. The nucleolus loses its compact 
and almost solid appearance, and often becomes vacuolated. 
At the same time the nucleus as a whole exhibits a change 
of shape. From being spherical, it passes into a kind of 
tetrahedral form with one angle directed towards the cavity 
of each of the four cell-lobes respectively. This appearance 
becomes accentuated as time goes on, until a quadripolar 
spindle is formed (PI. XVII, Fig. 42). I was unable, in this 
plant, to observe with certainty the presence of well-defined 
centrospheres, and this seemed a little strange, as they are so 
obvious in some other liverworts (cf. Fossombronia). The 
duration of the quadripolar spindle condition is but brief, and 
it is eventually replaced by an ordinary bipolar spindle. But 
when this spindle is examined, it is seen to be always arrayed 
with regard to the symmetry of the spore-mother-cell. That 
