328 Mottier . — The Development of the Heterotypic 
ceding pages. Because of this fact only those steps will be described and 
illustrated which seem to the writer to be necessary to clear up certain 
details upon which the main difference of opinion rests. 
The nucleus of the pollen mother-cell in Tradescantia just prior to 
synapsis is shown in Fig. 34. Here it is seen that the chromatin is 
distributed in the linin network in the form of lumps or granules of rather 
uniform size, which show a tendency to aggregate into masses or groups. 
Miyake (’ 05 ) has evidently represented a similar condition in his Fig. 135. 
Judging from the series of figures of Farmer and Shove (’ 05 , Figs. 23-26), 
it would seem that the chromatin granules are more finely divided, unless 
the difference between their illustrations and that of the writer is due to 
a difference in magnification or in methods. Whether the chromatin 
becomes more finely granular before synapsis, as shown for certain cases 
in Podophyllum and Lilium Mart agon, cannot be stated. However, there 
is no doubt but that in some cases, at least, the structure of Fig. 34 passes 
directly into synapsis, for, in some preparations, the nuclei in one loculus 
were found with this structure, whilst in the adjacent loculus nearly all 
nuclei showed almost the completely balled- up condition. Inasmuch as 
the nuclei in the same anther are nearly all in the same or very closely 
related stages, there can be little room for doubt concerning the accuracy 
of this statement. Farmer and Shove neither describe nor figure the 
tightly balled-up condition of complete synapsis. They represent the 
first contraction figure as a partly contracted spire m only ( 1 . c., Figs. 27, 
28, 29) without an evident nuclear membrane. In all preparations of the 
writer showing this stage, a well-defined boundary always exists between 
the nuclear cavity and cytoplasm. The pollen mother-cells still form 
a compact tissue,, but before the contracted ball has progressed far in its 
loosening up the cells round off and separate. It seems that the rounding 
off of the cells occurs sooner, or perhaps more rapidly, than in the other 
plants here described. 
As the spirem emerges from the contracted mass, it is seen to be 
double or split lengthwise, though the halves divaricate only slightly at 
certain places. On coming out of synapsis there is in many nuclei a very 
marked regularity in the loops or turns of the spirem as they emerge from 
the remaining entanglement, which suggests the ‘ bouquet stage * described 
for certain insects (Fig. 35). According to Farmer and Shove ( 1 . c., 
Fig. 32), the chromatin thread of the hollow spirem is disposed in the 
form of very uniform loops, showing a marked pole and anti-pole sides. 
Miyake’s figure ( 1 . c., Fig. 138), however, does not show any greater 
regularity than in other plants. 
The rearrangement of the hollow spirem, or the so-called second 
contraction, agrees in general with what has already been described in the 
preceding pages. The regularity in the formation of the loops is somewhat 
