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Charles E. Allen 
together, suggest that an analogous condition of cell polarity may prove 
to be relatively widespread araong the higher plants. 
The question of a polar organization of the cells of bryophytes, as of 
those of other plants, has hitherto been discussed mainly with reference 
to the presence or absence of centrosomes or related structures. Only 
in the spore mother cells of Anthoceros, so far as known, is a Suggestion of 
such an organization furnished by the behavior of other cell organs. In 
each mother cell, as was first shown by von Mohl (1839), a single chro- 
matophore givesrise, by two successive divisions, to four; the positions of 
these four c-hromatophores seem, from the descriptions of Strasburger 
(1880) and Davis (1899), to be related to the orientation of the spindle 
figures of the two ensuing mitoses, though the precise relation is not quite 
clear. Cell division is effected, according to Strasburger and to Van 
Hook (1900), by fibers whieh are centered upon the chromatophores. 
Apparently the first description of centrosome-like structures in a 
bryophyte was by Schottländer (1892), who saw a darkly-stained 
granule at each spindle pole in divisions preceding spermatogenesis in 
Marchantia. Centrosomes accompanied by asters are described by Mottier 
(1899) and Van Hook (1900) in vegetative cells of the same plant. Ikeno 
(1903) finds centrosomes of nuclear origin, without asters, in connection 
with all the antheridial mitoses; Miyake (1905) sees asters without centro- 
somes in all these mitoses except the last, during whieh a definite body 
appears at each pole; Escoyez (1907) finds no asters at all, and centro- 
some-like bodies in the last division only; Schaffner (1908) sees centro- 
somes in all divisions, accompanied in the earlier cell generations by 
asters; Woodburn (1911) finds no such bodies excepting in the androcyte 
mother cell, and he is not clear as to the behavior or fate of the two granules 
whieh appear here. 
In Fegatella, Miyake’s results are the same as in Marchantia, although 
“centrospheres” with asters had been described by Farmer (1895« — h) 
as present in the spore mother cells and the germinating spores. Bolleter 
(1905) finds asters in the dividing spore mother cells, but neither centro- 
somes nor asters in connection with the antheridial divisions; the results 
of Escoyez’s study of the antheridia are likewise negative; on the 
other liand, the Leeuwen-Reijnvaans (1908) describe centrosomes 
of nuclear origin, without asters, in the dividing antheridial cells. 
Woodburn (1911) finds the conditions the same as in the antheridia of 
Marchantia. 
Garber (1904) finds asters without centrosomes in sporophytic 
mitoses of Ricciocarpns. According to Lewis (1906), centrosomes with- 
