494 Farmer. — On Spore- Formation and 
linin filament ; these are all enclosed in a wall, and are bathed 
in sap. The nucleus as yet, however, is by no means as 
structureless as it (probably only apparently) becomes at the 
time when the spores are lying free within the sporogonium. 
The separation of the spores is effected by the disappearance 
of the outer wall of the enclosed tetrad, and by the degrada- 
tion of an extremely thin film in each of the recently-formed 
dividing walls. It is very easy to miss the stage of disappear- 
ance of the outer walls, but it is quite clear if observed at the 
right time. 
Germination of the Spores of Fegatella. 
The spores of this plant germinate while still enclosed 
within the sporogonium, as do those of Pellia , but the process 
does not begin so early as in the latter-named plant. The 
difference in character between the gametophyte divisions as 
contrasted with the spore-mother-cell mitoses is most striking. 
The whole process accords with what we are accustomed to 
regard as the normal type of karyokinesis, and in this respect 
it compares favourably with Pellia , in which owing to a com- 
paratively slight modification the proper relations are very 
much obscured. But Fegatella also exhibits a little variation, 
and it was by a comparative study of these differences that 
I arrived first at a clear idea of the structure of the gameto- 
phytic chromosomes in Pellia. 
The resting nucleus in the newly-formed spores contains 
one or more deeply staining nucleoli and a tangled thread of 
linin, which is especially grouped in their vicinity. The rest of 
the nucleus is filled with a clear nuclear sap and the whole 
is enclosed by a nuclear wall. As the nucleus prepares for 
division, the linin alters its appearance, though still very 
delicate, forming a convoluted thread which exhibits frequent 
anastomoses. 
The thread is stretched across the nucleus in various 
chromatin. The researches of Zacharias seem to entirely negative the probability 
of any such crude hypothesis. [Zacharias, Ueber d. Nucleolus, Bot. Zeit. 1885.3 
See also below. 
