Horváth Géza (szerk.): A Magyar Természettudományi Múzeum évkönyve 8. (Budapest 1910)
Soós, L.: A Helix arbustorum hím csirasejtjének fejlődése
SPERM IOGEN'ESIS 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 P ERÉNYI'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, but degenerates shortly after division, and arises newly after every division. -K The behavior of the chromosomes of the spermatocytes are important a»s 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 spermatogonial 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 transforming 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 connection 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 consequence 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 (Pl. IX., Fig. 3). They obtain a more
