MITOSIS IN PELLIA.* 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY. 
ALIA, 
CHARLES J. CHAMBERLAIN. 
(WITH PLATES XII-XI1V) 
Just as an understanding of the gametophytes of the flowering 
plants has been gained by a comparative study of the progressive 
reduction of the gametophytes of the higher cryptogams, so, in 
our opinion, the processes of nuclear and cell division in the 
flowering plants will be understood only after an investigation of 
these processes in lower forms; and just as the pteridophytes 
show the transitions which have cleared up the homologies of 
the gametophytes, so, it seems probable, the Hepaticae, in their 
modes of mitosis, show the transitions which will lead to a cor- 
rect interpretation of mitotic phenomena in the flowering plants. 
The Hepaticae, however, have received comparatively little 
attention from cytologists. 
In 1893, Schottlander (30)? described the sexual cells of 
several liverworts, paying particular attention to spermatogenesis. 
In the antheridia of Marchantia he found that the centrosomes 
divide during the anaphases of mitosis, so that each daughter- 
nucleus is accompanied by two centrosomes; but in the egg, 
centrosomes were not identified positively. 
In 1894 Farmer (8) reported a quadripolar spindle in spore 
mother-cells of Pallavicinia. According to this account, the 
chromatin of the spore mother-cell breaks up into sixteen chro- 
mosomes, four of which are then conveyed simultaneously to 
each of the four spores. In the same year Farmer (9), in 
collaboration with Reeves, described centrospheres in the germi- 
nating spores of Pellia. In the following year Farmer (10) 
*Published concurrently in the Decennial Publications of the University of 
Chicago 10: 327-345. 1903. 
* Figures in parentheses refer to literature cited at the end of the article. 
28 [JULY 
