No. 463.] STUDIES ON PLANT CELL.— VI. 495 
loops. It finally divides into six segments which are interpreted 
to be six pairs of chromosomes joined end to end. These six 
segments are then bivalent chromosomes. The two chromosomes 
of each pair (segment) finally come to lie side by side in various 
positions by the bending of the original looped segments and the 
separation of their two ends in the middle. The halves of the 
six bivalent chromosomes (segments) are distributed by the first 
mitosis so that there is the effect of a transverse division of six 
chromosomes at this time, but really the process is one of the 
distribution of twelve chromosomes in two sets of six each. 
The longitudinal fission of the spirem thread becomes more con- 
spicuous towards the end of the first mitosis so that the twelve 
chromosomes become partially split and pass as V’s to the poles 
of the first spindle during telophase. This premature division 
is preparatory for the second mitosis (homotypic) when the sepa- 
ration is finally effected. There is then only one longitudinal 
fission of the original spirem in the spore mother-cell and this 
prepares the chromosomes for the second mitosis, which differs 
only from the typical mitoses in the premature splitting of its 
chromosomes. The first mitosis is merely the separation of pairs 
of chromosomes joined end to end. Strasburger interprets the 
conditions in Tradescantia and Lilium in a similar way believing 
that the complications there simply arise from a more involved 
looping of the spirem thread. Strasburgers account of Gal- 
tonia then supports in all essentials the theory of Farmer and 
Moore. 
Strasburger in the same paper (04b) gives an account of 
synapsis which cannot be brought into harmony with that of 
Allen. The chromatin granules are reported to gather during 
synapsis into as many centers, which he names “ Gamozentren," 
as will finally form the reduced number of bivalent chromosomes 
(six in Galtonia). The “ Gamozentren " then become arranged 
and drawn out into the spirem which emerges from synapsis. 
The chromatin granules are named “ Gamosomen " and the 
bodies formed in the ** Gamozentren " which afterwards become 
the bivalent chromosomes of the first mitosis are called ** Zygo- 
somen." There are then no organized chromosomes during 
synapsis and no place in Strasburger's account for the fusion of 
