62 Davis. — The Fertilization of Batrachospermum. 
attempt to account for a transfer of the nucleus of the anthero- 
zoid to the carpogonium by ooblastema-filaments put out from 
the trichogyne. 
It is characteristic of the trichogynes of Batrachospermum 
that they remain a long time in good condition, only dis- 
appearing with the gradual disruption and decay of the whole 
cystocarp. But several changes often take place in the 
character of the cell-contents. The nucleus usually increases 
in size, and often a very interesting process of fragmentation 
takes place. This latter phenomenon may occur in the 
antherozoid, in the trichogyne, or in both structures at the 
same time. It consists of a gradual breaking up of the nucleus 
into two or more smaller masses, which still take the dark 
blue stain with haematoxylin. Fig. 13 illustrates a simple 
case of fragmentation in both antherozoid and trichogyne. 
In Fig. 14, two large portions of the nucleus in the tricho- 
gyne lie one at the base and the other near the middle of 
that structure. The nucleus of the antherozoid is very 
granular, and perhaps is about to split up into a great many 
small fragments of the character shown in the antherozoid 
of Fig. 15. Fig. 16 illustrates an interesting case in which 
there were two well-defined nuclei in the antherozoid, and 
the nucleus of the trichogyne lay at the top of that cell. The 
phenomenon of fragmentation often gives rise to appearances 
which might be incorrectly interpreted if one were not familiar 
with the process. In Fig. 17 there is shown a large prominent 
nucleus in the upper portion of the trichogyne that might 
be considered as a fusion-nucleus ; but the protoplasm in the 
central portion of the trichogyne was very dark, and gave 
indications of organization, and the question might well be 
asked whether it was not the remains of the nucleus of the 
trichogyne. Again, the cell-contents of the antherozoid may 
be almost hyaline but for a few scattered dark granules, and 
there may be one large nucleus in the trichogyne ; but it is 
quite possible that fragments of a divided nucleus as small 
as those shown in Fig. 15 might readily be quite lost when 
scattered in the cytoplasm. If the nucleus of the antherozoid 
