THE SPERMATOGENESIS OF Hysprip PEAS 525 
side of the vacuole; when it enters into the synapsis stage it is 
probably already in the form of acontinuous spireme. It is much 
bent with short turns and appears usually to be homogeneous and 
not split; the spireme at this time closely resembles the much 
convoluted thread with its short, sharp turns as it emerges from 
the synapsis stage. Since the chromatin assembles in a spireme 
before the so-called synapsis condition the significance of the 
latter is not apparent in these forms. 
The cytoplasm of the spore mother-cell is reticular and it 
always, from the spore mother-cell to the tetrad, retains this 
structure. In this regard the pea is very different from the cotton 
hybrid in which kinoplasm forms a marked character of the cyto- 
plasm in the more advanced stages of spore formation, and from 
some of the homologous cells of Syringa Rothomagensis * in which 
kinoplasm is strongly developed. The exaggerated development 
of kinoplasm or filar-plasm in the cytoplasm of the spore mother- 
cells is therefore not a constant or diagnostic feature of hybrids. 
Although I did not study closely the origin of the achromatic 
figure, I observed that it is derived from a multipolar one. The 
multipolar spindle originates in groups of fibers which are placed 
near the outer edge of the cytoplasm and which radiate from a 
common point towards the nucleus. The place of genesis of the 
achromatic figure is therefore very different from that of the cot- 
ton hybrid, and the structural reason appears to lie in the presence 
in the latter, and absence in the former, of a dense perinuclear zone 
of cytoplasm. The achromatic figure in cotton originates inside 
of this perinuclear zone, which thus appears to inhibit its more 
peripheral origin, It may also be that the zone of denser cytoplasm 
which in the cotton closely surrounded the nucleus not only formed 
a limiting boundary for the spindle, but at the same time made 
necessary for the mechanical support of the cell the formation of 
an outer layer of kinoplasm, and that its absence in the pea not 
only changed the structural relations of the parts of the cell but 
altered the mechanical condition as well, making the formation 
of the kinoplasmic layer unnecessary. 
The first maturation mitosisis heterotypic. The chromosomes in 
the metaphase are not different from those in the pure races Fillbasket 
* Juel, H. O. See bibliography. 
