98 Woodburn . — Spermatogenesis in Blasia pusilla, L. 
described in the Bryophytes, Wilson in Milium , A trie hum, and Pellia , and 
Ikeno in Marchantia. 
In order to understand fully the development of the sperm it is well 
at this point to compare the views we have in the various figures. Figs. 6 , 
7, 9, and 11 are corresponding views, all being drawn in a plane at right 
angles to the plane of the last division, while Figs. 8, 10, 12, and 13 each 
represent a plane parallel to that of the last division. 
The blepharoplast following near the plasma membrane develops into 
the shape of a comma and approaches a circle. The nucleus in the mean- 
time grows more homogeneous in appearance (Figs. 10, it , and 12), and 
becomes crescent-shaped and more closely applied to the blepharoplast. 
After the stage represented by Fig. 12, it becomes quite difficult to distin- 
guish between blepharoplast and nucleus. The latter seems to increase 
slightly in size as it becomes more drawn out, and extends from a crescent 
to a circular form. In Fig. 13 the sperm has lengthened out until it makes 
somewhat more than one complete turn within the mother membrane. The 
cytoplasm, which was at first collected within the concavity of the nucleus, 
eventually disappears, much of it evidently going towards the increase in 
size of the body of the sperm. 
In the stage represented by Fig. 13, the ends of the sperm overlap so 
closely that it is often difficult to distinguish the two, so that from an 
observance of this stage only, one might be led into the error of thinking 
the sperm a complete and closed ring. It is only by following it through 
its developmental stages that its true nature can be ascertained. M. Leclerc 
du Sablon (’88) describes a similar picture for Metzeria furcata. In 
'speaking of the developing sperm, he says : ‘Around the periphery of the 
cell a thin thread of cytoplasm differentiates, forming a complete circle. 
The nucleus comes into contact with this thread, . . . becomes smaller and 
the cytoplasm less dense. The thread or filament seems to be made up 
from nucleus and cytoplasm. Finally, the nucleus seems to disappear 
entirely, its substance having been used up to form the sperm. One can 
see only a colourless vacuole in the centre of the ring formed by the 
sperm. . . . Soon the ring breaks, the filament thins and lengthens, and 
gradually acquires the form of the mature sperm.’ No figures accompanied 
M. Leclerc du Sablon’s paper, but his descriptions lead one to believe that 
the figures, if drawn, might have compared quite closely with those of 
Blasia pusilla , as shown by Figs. 12 and 13. 
No mature sperms from the antheridium were obtained, but Fig. 14 
shows the form frequently found in sections. It is very difficult to obtain 
them in this way with the cilia intact. These are so long (Fig. 14 shows 
one approximately 58 microns in length, although they vary much in size), 
and coiled together in such a manner that the knife usually cuts them at 
some point or other. In antheridia, however, which are full of mature 
