174 
Davis. —Nuclear Studies on Pellia. 
spirem-thread, which soon segments into the chromosomes. 
The thread bears granules irregularly disposed in two rows. 
The first indication of spindle-development appears in a 
zone of granular kinoplasm closely investing the nucleus. 
Fibrillae are developed in this zone, appearing most numerously 
in the four regions where the lobes of the spore-mother-cell 
diverge from the centre. As the nuclear membrane fades 
the fibrillae enter the cavity, usually from more than two 
points. 
At this period of mitosis an appearance is frequently pre- 
sented similar to Farmer’s (’94) account of a four-poled spindle, 
there being four conspicuous sets of fibrillae running into each 
lobe of the spore-mother-cell. This is however a prophase 
of mitosis, and all trace of these four regions of fibrillae is lost 
with the metaphase. There is no four-poled spindle. 
The mitoses in the spore-mother-cell are two in number, 
and successive, with a short period of rest between the first 
and the second. The spindles are remarkable for the great 
breadth of their poles and the number and delicacy of the 
fibrillae that traverse the axes. The poles of the spindles 
are never occupied by bodies comparable to centrospheres 
or centrosomes. On the contrary the development of the 
spindle follows closely the plan generally presented by Sper- 
matophytes and Pteridophytes, the fibrillae acting individually 
or in groups or bundles, to a great degree independently of 
one another and uncontrolled by fixed centres. 
The rod-shaped chromosomes split longitudinally in each 
mitosis. There is no premature division of the mother- 
chromosome by double longitudinal splitting to . give four 
daughter-chromosomes, such as has been reported by Gui- 
gnard (’99) and Strasburger (’99) for several Spermatophytes. 
On the contrary the daughter-nuclei, following the first mitosis, 
pass into a resting condition, and the chromosomes, breaking 
up into granules, seem to lose their form and cannot be 
distinguished. 
The cell-walls separating the spores are laid down from 
cell-plates formed with each nuclear figure in the manner 
