300 W oo db urn. — -Spermatogenesis in certain Hepaticae . 
into two triangular sperm cells, which lie in pairs, and are not separated by 
a cell-wall. During this division the centrosome does not disappear, but 
persists to function as the blepharoplast. It remains, at first, in the corner 
of the sperm cell originally occupied by the pole of the spindle, then it 
moves into one of the acute angles of the cell. Shortly thereafter, a large 
body ( Nebenkorper ) appears in the cytoplasm for a short time, and then, 
during the formation of the blepharoplastic band, disappears. Whether, 
like the centrosome, this body is of nuclear origin or not, Ikeno did not 
determine with certainty. 
After the centrosome has taken up its position in one corner of the 
sperm cell, it lengthens slightly, keeping in contact with the plasma mem- 
brane, and soon develops two cilia. Then the nucleus moves so as to come 
in contact with the plasma membrane on the same side along which the 
centrosome has stretched out to function as a blepharoplast. In this 
position, the nucleus changes both in form and structure. It becomes 
homogeneous in staining capacity, and begins to flatten or draw out in 
a bow-like form. In the meantime, a protoplasmic projection has grown 
out from the nucleus in the direction of the blepharoplast until the two are 
united. The nucleus continues to lengthen until it becomes a narrow band, 
and the cilia long slender threads. At the same time the cytoplasmic mass 
decreases in size until only a small vesicle is left at the posterior end of the 
nucleus, while from the anterior end of the latter a very narrow band 
extends forward to the diminished blepharoplast. The latter grows only 
a short distance towards the nucleus, and then becomes smaller, and practi- 
cally disappears as the cilia develop, so that the forward end of the sperm 
projecting beyond the nucleus consists of a short, scarcely perceptible 
blepharoplast, bearing two cilia, and connected to the nuclear portion by 
a band of cytoplasm. Posterior to the nuclear portion is a cytoplasmic 
vesicle. The whole body of the sperm is more or less loosely coiled ; it is 
formed of three metamorphosed elements of the cell — the centrosome, 
which has become the blepharoplast, the nucleus, which forms the main 
body of the sperm, and the cytoplasm, which forms the posterior vesicle 
and the band connecting the nucleus with .the blepharoplast. The cilia 
may consist partly of material derived from the blepharoplast, and partly 
from the cytoplasm or plasma membrane of the sperm cell. 
Bolleter (’05) described briefly the spermatogenesis of Fegatella conica. 
This description agrees mainly with that of Ikeno for Marchantia , except 
that Bolleter failed to see the centrosome-like body at the poles of the 
spindle in the prediagonal divisions of the antheridial cells. However, 
since he found such a body occupying the region of the spindle pole of the 
last division, and also observed its nuclear origin, he concludes that it must 
be present also in the earlier divisions. 
Lewis (*06) found centrosome-like bodies at the poles of the spindles 
