Cell Structure, Growth and Division in the Antheridia of Polytrichum etc. 161 
out asters appear in connection witli most, and probably all, of the an- 
theridial divisions, but not in the dividing spore mother cells, of Rieda 
and Ricdocarpus. Beer (1906 a) also finds nothing resembling a centro- 
some in dividing spore mother cells of Rieda : and Miss Black (reported 
by Woodburn, 1911) finds no such bodies in any of the antheridial divi- 
sions of Rieda. 
Miyake (1905) finds no centrosomes in connection with the antheridial 
divisions of Makinoa, and Ikeno’s (1904) results for the earlier divisions 
are similar. 
Farmer (1894, 1895a) sees centrospheres and asters in dividing spore 
mother cells of Aneura\ Miyake finds asters, but no central bodies. during 
the antheridial divisions. 
Pellia has been more studied than any other bryophyte with reference 
to the presence of structures of this dass. Farmer and Reeves (1894) 
find centrospheres and asters in the germinating spores; and their results 
are corroborated by J. E. Humphrey (1895) and by Strasburger (1895). 
Farmer (1895 a) also describes centrospheres, each containing a minute 
centrosome, at the poles of the “quadripolar spindle” in the spore mother 
cell. Davis (1901) and Chamberlain (1903) find asters, frequently 
associated with centrospheres, in connection with the first two or three 
divisions of the germinating spore; no aster or centrosome is visible, 
according to Chamberlain, in the later germination divisions, in the 
apical region of the thallus or in young antheridia; nor, according to 
Davis, in the dividing spore mother cell. Gregoire and Berghs (1904) 
differ from their predecessors in that they find distinct asters in the fourth 
and later divisions of the germinating spore, but none in the first three 
divisions. Miyake (1905) sees asters without centrosomes, the Leeuwen- 
Reijnvaans (1908) centrosomes without asters, in the antheridial divisions; 
and Wilson (1911) finds in some of the later divisions (but not in the earlier 
ones) asters, sometimes with a small granule at the center of the radiations. 
Farmer (1895 a) finds centrospheres and asters in dividing arche- 
sporial cells and spore mother cells of Fossombronia; but H. B. Humphrey 
(1906) finds no central body in any of the antheridial divisions nor in 
the division of the spore mother cells. No central bodies or asters are 
found by Farmer (1895 a) in spore mother cells of Scapania ; by Farmer 
(1894) or Moore (1905) in those of Pallavidnia; nor by Woodburn (1911) 
in the androgones of Asterella or of Porella. 
Among the musci, as already noted, the Leeuwen-Reijnvaans 
(1907 b, 1908) find centrosomes in all the antheridial divisions of Polyt- 
richum and Mnium ; but their Statements are contradicted by Arens 
Archiv f. Zellforschung. VIII. 11 
