432 Wilson . — Spermatogenesis in the Bryophyta. 
remains attached to the blepharoplast, but a short interval is often found 
between them. 
Considerable changes have meanwhile gone on in the structure of the 
nucleus. At the time when the rod-like bodies are present in the spermatid it is 
almost spherical in form. During the formation of the limosphere a consider- 
able increase in size goes on, and the nucleus passes to the periphery, occupy- 
ing a lateral position in the cell (PI. XXXVII, Fig. 32). Its structure is now 
homogeneous, for, as already described, the nucleolus is no longer present. 
The bodies shown in Figs. 32 and 33 apparently in the nucleus probably 
lie above or below it. The blepharoplast now elongates, producing a short 
thick bar-like structure which lies closely pressed against the periphery of the 
spermatid (Figs. 30 and 33). A similar elongation of the blepharoplast has 
been described by Ikeno ( 32 ) in Marchantia , but in this case, judging from 
the figures given, the extension is away from the spot which will finally be 
occupied by the apex of the spermatozoid. In Mnium , on the other hand, 
the elongation is towards the anterior part of the spermatid. Shortly 
afterwards a thread-like structure develops in connexion with the blepharo- 
plast and passes over the inner contour of the cell membrane in a direction 
opposite to the previous elongation (Figs. 34 and 35). It was not deter- 
mined whether this thread is produced by an outgrowth from the blepharo- 
plast substance or by a differentiation of the cytoplasmic membrane of the 
cell. The thread soon reaches the portion of the cell periphery in contact 
with the nucleus and passes some distance beyond it (Figs. 35-8). At 
this stage the attachment of the appendage of the limosphere to the blepharo- 
plast can almost always be distinguished, the connexion being found at the 
junction of the thread and the thick bar-like portion (Fig. 37). In some 
cases, however, the appendage, although directed towards this point, does 
not quite reach it (Fig. 34) ; occasionally a projection of the appendage 
beyond the blepharoplast has been discovered (Fig. 36). 
During the elongation of the blepharoplast the limits of the nucleus 
are difficult to define, and can only be distinguished in preparations which 
have been subjected to prolonged staining in Flemming’s or Breinl’s triple 
stains. As a general rule, the nucleus does not extend quite up to the 
blepharoplast. Very soon after the production of the thread elongation 
takes place, and the nucleus soon reaches the anterior end of the bar-like 
structure produced by the elongation of the blepharoplast (Fig. 39). The 
nucleus continues to elongate (Fig. 40), and at the same time stains more 
deeply. It can be easily seen extending around almost the entire periphery 
of the spermatid in contact with the thread, and even at this stage the 
appendage is still faintly distinguishable (Fig. 41). 
At the latest stage discovered in the preparations the spermatozoid 
was almost mature. The nucleus has now attained a length of about one 
and a half turns of a spiral, and at the same time has decreased considerably 
