Davis, — The Fertilization of Batrachospermum. 65 
20 and 21). Eventually the chromatophore of the trichogyne 
becomes separated from that of the carpogonium, as in 
Fig. 2i, an example of a mature trichogyne in which this 
body is particularly well developed. As the trichogyne 
grows old, the colour of the chromatophore gradually changes 
from the peculiar somewhat bluish-green tint to a green with 
a trace of yellow in it, becoming at the same time somewhat 
fainter in colour. With the change in tint comes the same 
difference in the character of the protoplasm which we have 
considered in the case of B. moniliforme , namely, a change 
from a homogeneous appearance to a granular structure with 
a less definite outline. 
The writer found several instances of an abnormal develop- 
ment of the trichogyne that are worth noticing. The terminal 
cell of a procarpic branch had given rise to a process, but the 
latter, instead of developing directly into the trichogyne, had 
grown out and divided into two cells, thus continuing the 
growth of the branch (see Fig. 22). This exhibition of vege- 
tative character in the young trichogyne is exceptional and 
interesting, but quite in keeping with its structure as a nucle- 
ated cell. 
The phenomenon of fertilization may be studied very 
advantageously here, because the antherozoid sends out 
a very distinct process. After the act of protoplasmic fusion, 
the long delicate strand of cytoplasm between the trichogyne 
and carpogonium (see Fig. 23) becomes thinner, and finally 
breaks. The separated ends contract, but do not round 
themselves off quickly. Fittle extensions from the upper 
portion of the carpogonium and lower portion of the tricho- 
gyne are frequently found when these structures must have 
been long separated from each other. Between the separated 
portions of protoplasm is deposited a substance apparently of 
the same nature as the cell-wall. The nuclei of this species 
are very small, but they stain very deeply indeed. That 
of the trichogyne usually lies near the middle portion of the 
cell, but occasionally at the tip (see Fig. 25). The nucleus 
of the antherozoid is very irregular in its situation, and 
F 
