478 Farmer. — On Spore-Formation and 
hump is brought about here, exactly as in Lilies 1 , by a bending 
over on itself of the elliptical chromosome, and by the divari- 
cation of the limbs formed at the place of bending. Finally 
the chromosome splits across its middle, that is, across the 
hump, and the daughter-chromosomes immediately open out 
to form V-shaped bodies. The limbs are very short, and so 
the daughter-chromosome may easily be mistaken for a rod, 
but in a number of cases V-shaped chromosomes were certainly 
observed. Of course, this does not exclude the possibility of 
variations occurring, such as have been described 2 for Lilies 
and animal cells. In any case, it will be seen that the division 
of the chromosome is really longitudinal, and not a transverse 
one, as it would have been had not the chromosome doubled 
on itself to form the hump already referred to. This doubling 
over on itself, and the subsequent separation of the daughter- 
halves of the chromosome, can easily be understood by bending 
a wire ellipse in the manner described, and on pulling out the 
two ends thus formed, it will be found that the originally (ap- 
proximately) parallel sides, which represent the two halves of 
the chromosome, are thereby separated from each other. 
After the separation of the chromosomes, the two daughter- 
nuclei are formed, and a cell-plate appears in the connecting 
spindle. It is very delicate, and in spite of devoting con- 
siderable time to the question, I was unable to feel quite 
certain as to whether the spore-mother-cell is at once divided 
across by a wall into two cells. I believe, however, this is the 
case, and that in this respect Fossombronia conforms to the 
method of spore-formation, as seen in those other members of 
the Jungermanniae that were examined, in which this certainly 
takes place. The vacuolated character of the protoplasm, 
which causes it to be often thrown into plate-like films, greatly 
increases the difficulty of arriving at a definite conclusion. In 
one spore-mother-cell (Fig. 12) the division of the cell appeared 
to be deferred until after the second mitosis. 
1 Farmer and Moore, On the Essential Similarities existing between the Hetero- 
type Nuclear Divisions in Animals and Plants. Anat. Anzeiger, Bd. XI, 1895. 
2 Farmer and Moore, loc. cit. 
