SPERMIOGENESIS OF HELIX ARBUSTORUM. 
327 
that the nebenkern arises from the degenerating fibres of the spindle. 
The base of this statement is that the spindle fibres after division 
really melt together into a spherical homogeneous mass, as it is well 
visible in preparations fixed with Perènti’ s fluid, and stained with 
Benda’s crystal violet. This body is in some respects similar to the 
nebenkern, but it has nothing to do with it. It is not a constant part 
of the cell, bat degenerates shortly after division, and arises newly 
after every division. 
* 
The behavior of the chromosomes of the spermatocytes are impor¬ 
tant as regards the hypothesis of the individuality of the chromosomes. 
It is quite certain that the chromosomes once lose their individuality 
during the maturation divisions, viz., after the last ovogonial and sper- 
matogonial divisions. In young auxocytes no individual chromosomes are 
to be found until after the formation of the threads of the pachytene 
nucleus, and they disappear in some cases — which I recorded above — 
even during the growth period. The opponents of the hypothesis of the 
individuality regard this fact as a very important argument, on the 
contrary, the partisans of the hypothesis are of the opinion that the 
transformations of the chromosomes during the growth period is a minor 
matter as regards the individuality, because, as Boveri says, from the 
point of view of the individuality it would be quite indifferent even if 
the substance assuring the continuity of the chromosomes in the resting 
nuclei were present in an unstainable condition. 
The chromosomes of the male germ-cells of H. arbustorum lose 
their individuality not only after the last spermatogonial division, but, 
as seen above, also in the spermatocytes after the synapsis when trans¬ 
forming into a reticulum (PL VIII., Fig. 5). I hold this period of the 
development as less important as regards the individuality, because it 
could be thought that the chromosomes coalesce at their ends and 
form the reticulum, but they retain their individuality, though the con¬ 
nection of their chromomeres became looser. But the next stage of the 
development contradicts this suggestion, because the linin in this 
stage diminishes, and afterwards disappears almost completely, and 
thus disappears the substance connecting the chromomeres, in con¬ 
sequence of which the thread becomes dissolved into granules. We can 
find then in the nucleus only the remnants of the linin network, as 
well as chromomeres scattered through the unstained karyoplasm. The 
chromomeres in the next stage begin to group together at several points, 
but these groups are so little determined in shape that one cannot 
speak about true chromosomes (PI. IX., Fig. 3). They obtain a more 
