Htimaria rutilans , Fries. 
45 
A longitudinal split in the filament becomes evident, and was regarded by 
Allen as a separation of the threads which had previously fused. The 
spireme breaks up into a number of chromosomes which shorten and 
thicken while, at the same time, a second longitudinal split is distinguished. 
The limbs of the heterotype chromosome thus originate by a longitudinal 
split representing the separation of two fused, but originally independent 
filaments. The limbs of the chromosomes separate in the heterotype 
metaphase, and the second longitudinal split is completed in the homotype. 
A similar account is given by Gregoire (23) and by Berghs (3) for 
various other Angiosperms, and by Allen (2) for Coleochaete. 
In 1905 Farmer and Moore (18) published a full account of the 
reducing divisions or meiotic phase as studied by them in a number of 
animals and plants. 
They observed stages corresponding to those seen by Allen, Gregoire 
and Berghs, but they were also able to distinguish various others, and have 
interpreted them quite differently. 
According to these investigators, the heterotype division is initiated 
by the aggregation of the newly formed spireme towards one side of the 
nuclear area, forming the first contraction figure. As this loosens, the 
spireme undergoes longitudinal fission, but the split becomes more or less 
obliterated when the thread shortens and thickens in the synaptic or 
second contraction. During this process the nucleolus becomes vacuolate, 
and is regarded as giving up its substance to the chromatin element of the 
spireme. 
Loops extend from the contracted mass to the nuclear wali, and in 
these the longitudinal split is still obvious. The sides of the loops become 
drawn into parallel positions ; they are often twisted, and simulate the 
appearance of a single longitudinally split thread. This appearance is 
illusionary, since the earlier stages have been fully traced, and moreover 
the true longitudinal fission is still seen in the parallel sides. The synaptic 
tangle loosens, and the thread breaks up into chromosomes ; each of these 
represents a loop or similar segment of the spireme, and the two limbs of 
each bivalent chromosome are thus derived from diverse portions of the 
thread which have been bent towards one another. The original longi- 
tudinal fission is still visible, but disappears as the chromosomes shorten 
and thicken. During this process the chromosomes pass to the periphery, 
appearing to act under the influence of mutual repulsion. 
On the spindle the chromosomes break apart at their angle, the 
daughter chromosomes thus representing different portions of the spireme. 
In them the longitudinal split becomes once more apparent, and it takes 
effect on the spindle of the homotype division. 
The meiotic phase is thus regarded as a peculiar series of events 
resulting in the reduction of the chromosome number and interpolated 
