44 
H. E. Jordan 
that this particular nucleolus is the future accessory cliromosome. This 
is confirmed by the fact that after more prolonged staining in Auer- 
bach's solution it alone becomes shghtly green. Compared with typical 
ehromosome-nueleoli, however, it is peculiar in that it does not stain 
readily nor intensely with specific chromatin stains, and that it grows 
smaller again (though probably never quite disappears) during presynapsis. 
Its irregulär contoiu' (fig. 11) at this stage indicates that its diniinution 
in size is clue to loss of chromatin. This nucleolus appears to present 
a condition of less early differentiation than is the case with more typical 
ehromosome-nueleoli of such forms as Pyrrhocoris (Wilson, 09) and some 
of the orthoptera (e. g. Aplopus mayeri, Jordan, 1907). Its decrease in 
size may be only apparent, since it is frequently continuous with the 
spireme, in whieh case it is difficult to determine its exact limit proximally. 
b) Synizesis (contraetion phase) and synapsis (“bouquet stage”- 
Eisen). 
After a brief resting stage (protobroch nucleus, Winiwarter) the 
primary spermatocyte enters upon a growth phase (“auxocyte”) coin- 
cident with synizesis and synapsis (synaptenic spireme, Winiwarter). 
The increase in bulle is proximally two-fold, the daughter secondary 
spermatocytes (second generation of meiotic cells) having again approxi- 
mately the original size of the mother spermatocytes. The relative bulle 
of cell and nucleus appears to remain fairly constant throughout this 
period, the nucleus being comparatively very large. The cytoplasm is 
of the gramdo-reticular type. 
The delicate achromatic reticulum of the resting nucleus changes 
to a delicate, apparentlv continuous, deeply-staining spireme (leptotenic 
nucleus, fig. 11). The small irregulär ehromatic nucleolus remains con- 
spieuous. Here, as in later stages, plasmosomes may remain to confuse 
the picture, but the Auerbach’s stain will always reveal the identity of 
the chromosome-nucleolus. The threads now shorten and become 
coarser, remaining apparently continuous (fig. 12). During synizesis the 
thread becomes arranged in loops converging at that pole of the nucleus 
corresponding to the position of the centrosphere. At this same point 
also the accessory chromosome (monosome, or heterochromosome) is 
invariably located. There appears to be only one legitimate inference that 
can be drawn from this appearance i. e. that the centrosphere (idiozome) 
exerts an attraction on the loops and the accessory chromosome, as first 
suggested by Schoenfeld (1901), and recently more fully demonstrated 
by Büchner (1910). 
