Woodburn. — Spermatogenesis in certain Hepaticae. 31 1 
The fact that a body does sometimes occupy the pole of the spindle 
does not necessarily imply anything more than a probable concentration of 
cytoplasmic or kinoplasmic materials. 
The development of the blepharoplast in all these plants proceeds from 
a dense granular mass or spherical body, located usually in the most distant 
angle of the sperm cell. Evidence so far obtained indicates its origin 
as a condensation or aggregation of cytoplasmic material. The blepharo- 
plast becomes a cord, growing in close contact with the plasma membrane 
and entirely past the nucleus. The latter then draws out along the posterior 
portion of the blepharoplast and may extend beyond it, while from near the 
forward and slightly enlarged end two cilia develop. My observations 
lead me to believe that the ‘ Cytoplasmatischer Fortsatz * of Ikeno is merely 
a part of the blepharoplast. 
No body corresponding in size and appearance to the ‘ Nebenkorper ’ of 
Ikeno was found. 
According to some authors, the mature sperm represents three meta- 
morphosed elements of the cell, each of morphological rank, namely, the 
nucleus, the cytoplasm, and the blepharoplast or centrosome ; the centro- 
some and blepharoplast being held by some to be homologous. In the light 
of my observations I believe that no centrosome exists in Porella , Mar- 
chantia , or Fegatella , and that the blepharoplast arises de novo in the cell in 
which it is to function as the cilia-bearer. Escoyez takes the same view, 
save that he describes the blepharoplast as originating in the spermogenous 
tissue just previous to the last division, and occupying the pole of the 
diagonal spindle. These considerations tend to confirm the view expressed 
by Mottier (’04), that the fundamental substance known as kinoplasm 
possesses genetic continuity, and that the blepharoplast represents individua- 
lized parts of the kinoplasm arising de novo in certain spermogenous cells. 
We cannot at all times, by present cytological methods, differentiate the 
kinoplasmic part of the cytoplasm. 
We may thus consider the mature sperm to represent the two constant 
cell elements, nucleus and cytoplasm ; the main body, or the nuclear 
portion, representing the nucleus, the blepharoplast and cilia representing 
specialized parts of the cytoplasm, and the remainder of the latter being 
found in the cytoplasmic vesicle. 
These studies were carried out under the direction of Professor D. M. 
Mottier, to whom I wish to express my thanks for his kindly assistance and 
for his valuable and timely criticisms. 
Indiana University, 
August 31, 1910. 
Y 1 
