Archegonium ; and on Spermatogenesis in Poly trichum. 125 
the blepharoplast with the remaining deeply staining vesicle, and in all 
cases the nucleus is enclosed within the arch (Figs. 34-6). Fig. 34 shows 
a side view, and Fig. 35 a dorsal view, of a spermatid at this stage. The 
term dorsal is used in Belajeff’s (4) sense and refers to the side of the 
spermatid near which the nucleus lies. 
The arched band of the Polytriclmm spermatid is probably homologous 
with the c cytoplasmatischer Fortsatz ’ described by Ikeno in M archantia (9). 
In the latter plant this structure appears as a short arched band which con- 
nects the blepharoplast with the nucleus, and it is significant that, at 
the time of its formation, the ‘ chromatoide Nebenkorper ’, which has been 
situated in this region, disappears. It seems probable that the ‘Neben- 
korper ’ has been concerned in some way in the formation of the ‘ cyto- 
plasmatischer Fortsatz ’. There is, however, a marked difference between 
M archantia and Poly trichum in the situation of the ‘ Nebenkorper ’. In the 
Liverwort this body occurs between the blepharoplast and the nucleus, and 
the curved band, which is correspondingly short, is developed between the 
two in such a manner as to connect them. In Poly trichum , the ‘ Neben- 
korper ’ is situated on the posterior side of the nucleus (Fig. 36), and the 
arched band is consequently much longer and extends from the ‘ Neben- 
korper ’ to the blepharoplast in front, including the nucleus in its arch. In 
this respect Fossombronia agrees with Marchantia . In the former plant, 
Humphrey (11) uses the term ‘middle piece’ for the connecting band, 
or the ‘ cytoplasmatischer Fortsatz ’ of Ikeno. 
The difficulty experienced in tracing the changes which take place 
in the spermatid in the Bryophyta is indicated by the various conflicting 
statements which have been made with regard to the 1 Nebenkorper \ 
Woodburn (23) asserts that in Marchantia ‘ no body corresponding in size 
and appearance to the “ Nebenkorper ” of Ikeno was found ’. Arens (2) 
similarly asserts that no body of this kind occurs in Polytrichum juni - 
perinum ; while J. and W. van Leeuwen-Reijnvaan state that a body 
corresponding to Ikeno’s ‘Nebenkorper’ is present, but disappears before 
the spermatozoid is ripe. According to the present investigation, in Poly- 
trichum the ‘Nebenkorper’ does not disappear, but persists in the ripe 
spermatozoid. Some explanation of these opposing statements is probably 
found in the difficulty encountered in staining the spermatids at the time 
when the most important changes are taking place. 
The ‘ Nebenkorper ’ of Ikeno, which is conspicuous in the spermatids of 
Marchantia , Pellia, F eg at ell a, Fossombronia , A trichum, Mnium , and Poly- 
trichum , is probably functional in these plants and is concerned in the 
formation of the band-like body along which the nucleus extends itself. 
This conclusion is strongly suggested by the constant and definite con- 
nexion between these structures (‘ Nebenkorper ’ and arched band) in 
Poly trichum (Figs. 32-6). 
