CELL DIVISION BY FURROWING IN MAGNOLIA 
the leptoneme passes over into the pachyneme stage. In some cases 
the distance between the mother cells is once or twice their diameter, 
the individual cells being untouched by others on any side (fig. 12). 
In other instances they are found crowded together, especially in the 
ends or corners of the pollen sacs, so that each one touches other mother 
cells to the number of three to five (fig. 2). Even here the intercellular 
spaces are large (fig. 5), and the cells assume a spherical form. Rela- 
tively few cases are to be found in which a deviation from this shape 
seems to be due to crowding. Some cells in synapsis assume an elon- 
gated oval form, and occasionally the nucleus is found at one end of 
such a cell and the chromatin at the corresponding end of the nucleus. 
It is as if the chromatin thread had been attracted by something out- 
side the cell and had moved in that direction, causing the nucleus also 
to migrate toward one end of the cell. Similar abnormal conditions 
are in evidence in the mitotic stages of these cells. It may very well 
be that these are wound efTects, due to cutting the stamens from the 
flower before fixing them. Miehe (14) and Christman (4) found 
similar phenomena, such as the migration of the chromatin and nuclei 
from one cell into another, and suggested that they might be of a 
traumatic nature. R. S. Lillie (12) in 1903 found that free nuclei and 
those of sperms migrate toward the anode, but that cells with a large 
amount of cytoplasm go toward the cathode. Hardy (9) has more 
recently (1913) carried on further experiments on the effect of the 
electric current on cells, in general substantiating the conclusions of 
Lillie. It may be that these nuclear migrations, as the writer (6) has 
suggested is the normal procedure in Nicotiana, may be attributable 
to a disturbance in the electrostatic equilibrium of the cells of the tissue. 
All of the pollen grains in a given anther are not in the same stage 
of the reduction divisions, which is a very helpful fact in the study of 
pollen formation. There are frequently found lying side by side cells 
in diakinesis and in the anaphases of the homoeotypic mitosis respec- 
tively. It is not, however, usual to find presynaptic stages and young 
microspores in the same pollen sac. 
The stages of transformation within the nuclei are very marked 
and sharply defined in this material. There is an abundance of the 
bouquet, leptoneme, pachyneme (fig. i), diakinesis, and the other 
phases of the meiotic divisions. No good contraction stages, however, 
are to be found, excepting the apparently traumatic effects referred to 
above. The description of the processes involved in the reduction of 
