130 BOTANICAL GAZETTE [FEBRUARY 
with the cell membrane (jig. 68). When the cilia appear they are 
inserted in this very small body so that it comes to function as a 
blepharoplast. Its small size as compared with that of the cilia of 
the mature sperm makes it seem probable that some of the material 
for the growth of the cilia must be drawn from another source than 
the blepharoplast itself, although it disappears to such an extent 
that in the mature sperm it cannot be recognized as the point of 
insertion of the cilia. 
The developing spermatozoids of Riccia natans do not remain 
enclosed in the mother-cells until they are mature, but at about 
the stage represented by figs. 70, 71 the walls break down and the 
young spermatozoids lie free in the cavity of the antheridium. Here 
they seem to undergo considerable growth. The material for this 
growth is probably derived from the surrounding cells as they become 
collapsed in old antheridia. 
The nucleus of the developing spermatozoid takes a position at 
one side of the cell and becomes homogeneous. It seems probable 
that other material than the chromatin of the spermatid nucleus 
must enter into this part of the spermatozoid, because it is very 
evident that the body contains more material than would be obtained 
from the chromatin alone. Soon the nucleus elongates, following 
the outline of the cell and becoming crescent-shaped (figs. 71-73): 
In some cases, a distinct vacuole occurs in the cytoplasm although 
this is not always the case (figs. 71, 72). The mature spermatozoid 
becomes long and slender and consists of the nucleus, the material 
of which seems to have increased in amount, a small amount of 
cytoplasm, and the cilia which are derived from the blepharoplast 
and in all probability from a part of the cytoplasm surrounding it. 
IKENO describes a spherical body which appears in the spermatids 
of Marchantia before the cilia begin to develop and disappears about 
the time that changes take place in the nucleus. It has been impos- 
sible to find such a body in Riccia, although it would seem, judging 
from IKENo’s figures, that it could easily be seen if present. 
The question of the homology of the blepharoplast and centro- 
some is one which it seems to me has not yet been settled. In Mar- 
chantia, where centrosomes have been reported in the vegetative 
cells as well as in the antheridium, the evidence seems good that the 
