Horváth Géza (szerk.): A Magyar Természettudományi Múzeum évkönyve 8. (Budapest 1910)
Soós, L.: A Helix arbustorum hím csirasejtjének fejlődése
33-2 D, L. SOÓS later stage tliey are regular, rod shaped, with thickened ends. Along their longer axis a clear stripe is to be seen, from which might be concluded that they divide along this line, but this is according to BOLLES LEE — only an appearance, and due to the differences in the refraction of light. Then close to the nuclear membrane appear also the centrosomes which pass toward the opposite poles of the cell, and concurrently with their passing the spindle also becomes formed. According to P ROWAZEK (98) the second maturation division is not preceded by a strict resting stage, which is shown by the fact that the chromosomes remain even during this time, condensed and isolated. He states also that the chromosomes first appear close to the nuclear membrane, at which time all chromosomes gather in the part of the cell nearest to the centrosomes, and they arrange themselves after the forming of the spindle in its equatorial plate. I have had the opportunity of observing the second maturation division only from the anaphase (Pl. X., Fig. 5.). Later phases are shown on Figs. 6. and 7., Pl. X. These figures, as well as all my observations show that the second division does not differ at all from the first one. The chromosomes are also in this case ovoidal, and lie parallel with their longer axes to the axis of the spindle. The number of the chromosomes is equal to that of the first division, as is seen on Fig. (3., Pl. X., on which 18 chromosomes are clearly visible, some chromosomes, however, could not be shown in consequence of their position, but well distinguishable under the microscope. Pl. X., Fig. 7. shows the telophase. The chromosomes unite at the end of the telophase in a dense mass, in which even the single chromosomes are sometimes to be distinguished. The chromatin granules divide afterwards so equably through the nucleus that it seems to be quite homogeneous (Pl. X., Figs. 8., 10.). During the transformation of the nucleus the cytoplasm divides into two parts, and then we have to do with the spermatids. 3. Discussion of literature. The examination of the spermiogenesis of the Pulmonates began with DUVAL'S paper (24) published in 1S7S. DUVAL'S paper, as well as those of his immediate successors, BLOOJIFIELD'S (7) and BOUZEAUD'S (101) appeared in the childhood of the spermatological researches, therefore they could not obtain more important results in consequence of the incompleteness of the microscopical methods. These authors derived the spermatozoa from the most conspicuous cells of the genital gland, i. e. the base-cells.
