Wilson . — Spermatogenesis in the Bryophyta . 421 
cells. The spermatid becomes rounded, and later on a blepharoplast is 
found in the cytoplasm which soon migrates to the acute angle of the cell, 
becoming closely applied to the membrane. Previous to this a ‘ chromatoider 
Nebenkorper 5 appears in the cell and passes to a position just beneath the 
blepharoplast, where it becomes elongated, connecting up with the cytoplasm. 
The chromatin of the nucleus condenses, hiding the nucleolus, and the whole 
mass then becomes joined with the ‘ Nebenkorper ’, sharing in its elongation, 
and with it giving rise to the body of the spermatozoid. 
Lewis (43) in Riccia natans gives a somewhat similar account of the 
spermatogenesis. Centrosome-like bodies are present throughout the de- 
velopment, and these at the final diagonal division are very obvious ; no 
walls are formed between the daughter-cells resulting from this division. 
The bodies persist one in each spermatid in the neighbourhood of the 
nucleus, but later move to the end of the cell, coming into contact with 
the membrane and producing the cilia. No ‘Nebenkorper’ was found. 
Ikeno (35), in a discussion of the homology of the blepharoplast, after 
a consideration of these investigations, has concluded that in the Mar- 
chantiales the centrosomes perform their normal function as well as acting 
as blepharoplasts. In the course of the phylogeny of the Hepaticae, the 
original function of the centrosome has been lost to allow for its specializa- 
tion as the cilia-producing organ. 
Escoyez, in 1907 (22), in an examination of the divisions in the 
antheridium of Marchantia polymorpha , confirms the statements of Miyake. 
In the earlier divisions no centrosomes are present ; at the prophase the 
chromatic network is massed in the middle of the nucleus, no nucleolus 
being found. Then threads of chromatic material often pass outwards 
towards the membrane, and one or more granules are often found at the 
edge of the central chromatic mass, but these never pass out of the nucleus. 
No bodies are present at the spindle poles. Just before the final diagonal 
division bodies are found in each corner of the cell touching the cell-wall. 
Their origin could not be determined, and they probably arise de novo. 
Later on these bodies are found at the spindle poles, and they are still 
present at the telophase, persisting as blepharoplasts in the spermatids. 
The early divisions in the antheridium of Fegatella conica are similar, no 
centrosomes being present. Escoyez concludes that centrosomes are not 
present, and that the bodies which appear at the last division function as 
blepharoplasts only. 
Up to this time no detailed description had been given of the early 
development of the spermatogenic cells in the Musci, although Ikeno (33) 
had already noted the absence of centrosomes during the spermatogenesis 
of certain species. Arens (2) was the first to investigate this subject, basing 
his description on Polytrichum juniperinum. Shortly afterwards a series of 
papers dealing with the spermatogenesis of several species of Polytrichum 
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