82 BOTANICAL GAZETTE [ AUGUST 
forms a complete zone about the nucleus. The nuclear wall dis- 
appears, and the central part of the cell becomes filled with a 
network of kinoplasmic fibrils, in which the chromosomes lie. 
This network grows out into several projections, which become 
the primary cones of the multipolar spindle. These cones now 
unite at their apices into two groups and thus form the bipolar 
spindle. | 
In 1899 Williams describes for Passiflora a process somewhat 
resembling that which occurs in Cobaea. Upon the breaking 
down of the nuclear wall, there is a large kinoplasmic network 
formed in the central portion of the cell. This network of fibrils 
projects outward at various points and becomes cones, which, 
uniting at their apices in two groups, form the mature spindle. 
In 1900 the writer investigated the spindle in Gladiolus. 
Here, as in Equisetum, the first indication of the spindle in the 
mother-cell is the formation of a felted zone of kinoplasmic 
fibrils surrounding the nucleus. But instead of the fibrils taking 
on a radial arrangement, as described for Equisetum, the zone 
grows out at irregular intervals in the form of sharp pointed 
projections, which are the primary cones of the spindle. The 
nuclear wall remains intact until the cones are fully developed, 
and upon its breaking down the cones collect by the fusion of 
their apices into two groups, when the bipolar condition 1s 
reached. 
Byxbee (1900) has recorded the following method for the 
development of the spindle in the pollen mother-cells of Lavatera. 
The meshes of the network close to the nuclear wall pull out in 
a direction parallel to the wall, forming a felt of fibrils about the 
nucleus. The cytoplasm now collects in a dense granular zone 
about the nuclear membrane, as it does in Cobaea. Upon the 
breaking down of the nuclear wall, there is formed a central 
mass of fibrils in which the chromosomes are suspended. This 
central mass of fibrils grows out into several projections, bringing 
about the multipolar condition of the spindle. Two of the cones 
become more prominent than the others, which they absorb, and 
the bipolar figure is thus produced. 
Smith (1900) has worked out with considerable detail the 
