308 Woodburn . — Spermatogenesis in certain Hepaticae . 
cytoplasm in the peripheral region of the cell through which the blepharo- 
plast grows is denser than in the interior (Figs. 15, 16, and 17). 
Frequently a very dense band of cytoplasm extends somewhat beyond 
the posterior end of the developing blepharoplast (Figs. 17 and 18), as 
if possibly contributing to the growth of the latter. The blepharoplast 
throughout seems to be composed of similar material ; at least, no differen- 
tiation could be brought out in the staining. The conditions observed 
in the development of the blepharoplast indicate that the body shown 
in Fig. 13 represents cytoplasmic constituents ; that this body begins to 
grow into a cord, and enough material is added from the cytoplasm to pro- 
duce the mature threadlike blepharoplast. The position of the blepharoplast 
is quite similar (Figs. 17-20) to that of Chara^ as described by Mottier ( 5 04 ), 
but the form and development differ. The blepharoplast of Chara arises 
as a differentiation of the plasma membrane with the posterior end the 
thicker, while in Porella it grows from a spherical body, and the forward 
end is the larger. 
The chromatin granules gradually lose their identity, forming a homo- 
geneous mass which begins to draw out along the blepharoplast into a curved 
or crescent-shaped band (Figs. 19, 2c, and 21). The nuclear material now 
becomes so closely applied to the blepharoplast that the exact extent of the 
latter cannot be determined. The nuclear band continues to lengthen, 
describing eventually a little more than one turn within the cell-wall. The 
blepharoplast, or as much of it as can be seen extending from the nucleus, 
becomes thinner, but the forward end from which the cilia spring remains 
slightly thicker than the rest (Figs. 22 and 23). Fig. 22, which is still 
enclosed within the cell membrane, shows the cilia coming off from the rear 
of this thickened forward end of the blepharoplast and extending around 
the body of the sperm, and at certain points in contact with the cell 
membrane. Fig. 23 shows more distinctly the point of insertion of the 
cilia. The cytoplasm collects in coarse granules within the concave side of 
the sperm, mainly within the posterior or nuclear part (Figs. 21, 22, and 23). 
Mature sperms (Fig. 24) were secured by dissecting out antheridia from the 
antheridial branches, and allowing the sperms to escape in water on a slide. 
In about thirty minutes after escaping, they were killed with 2 % osmic acid 
and stained with anilin safranin and gentian violet. The blepharoplast 
is readily distinguished, extending forward from the nuclear portion and 
bearing close behind its tip a pair of cilia, which are somewhat longer than 
the entire body of the sperm. The blepharoplast is nearly straight, but the 
nuclear part is curved and forms a little more than one complete turn. The 
blepharoplast cannot be traced back along the side of the nuclear portion, 
but a distinct line extends beyond, which, together with the posterior end of 
the nucleus, encloses a small vesicle of apparently homogeneous cytoplasm. 
On comparing Fig. 24 with Figs. 17 to 20, we can readily see that this line 
