in Gracilaria confervoides , Grev. 217 
the lobes being right and left of the depressed procarpium. 
In many cases the placenta remains as in Fig. 5. 
2. The fused cells of the procarpium, which now have 
swollen walls, send out protoplasmic protrusions through these, 
and by means of them establish direct communication with the 
immediately adjacent placental cells. The protrusions are 
quite large enough to admit of the passage of a nucleus. 
3. From the fused procarpial cells other protoplasmic pro- 
trusions (diverticula) arise, and form spores at their free ends, 
independently of the placental cells (Fig. 5). 
4. The cells forming the free surface of the placenta de- 
velop as in Fig. 5, and produce radiating (in some cases bi- 
or even multi-radiate) rows of basipetally formed spores. 
5. The fused procarpial cells and the deeper-seated pla- 
cental cells, previously densely filled with granular protoplasm, 
show only peripheral layers of protoplasm enclosing large 
vacuoles. 
Many of the placental cells may be seen, in course of these 
changes, with two nuclei, as if about to fuse, or as if they were 
sister nuclei ; and, in many cases, the placental cells may be 
observed in direct communication with one another by proto- 
plasmic channels, like those found connecting the procarpial 
with the placental cells. 
Of the facts which have been observed I venture to put for- 
ward the following hypothetical explanation : — The nucleus 
which results from fertilisation fuses in turn with the nuclei of 
the combining procarpial cells. This complex nucleus then 
undergoes repeated division, and the daughter-nuclei pass, one 
through each of the previously mentioned protrusions, into the 
placental cells, there to fuse with their nuclei, this union being 
followed by division. This process occurs throughout the 
whole placenta, so that in the end each of the placental cells 
from which the spores are directly formed has received into its 
nucleus part of the substance of the nucleus formed by the 
fusion of the nucleus of the spermatium with that of the car- 
pogenous cell. I hope by a study of living plants to test the 
value of this supposition of nuclear fusion and distribution. 
