Horváth Géza (szerk.): A Magyar Természettudományi Múzeum évkönyve 8. (Budapest 1910)
Soós, L.: A Helix arbustorum hím csirasejtjének fejlődése
SPERMIOGENESE OF HELIX ARBUSTORUM. 307 the spermatocytes, in which the reduction actually took place, as spermatogonia. BOLLES LEE (10) gave a considerably different description of the division of the spermatogonia. In the spermatogonia — according to him — first appear 6 to 12 chromatin threads varying in length, from which develop 24 U-shaped chromosomes. Their ends are directed to a strictely determined point of the cell. The chromosomes split afterwards into two halves. The half threads are first parallel, but later separate, and spread in the nucleus. BOLLES LEE'S figure of this last stage of chromatin development agrees with my Figure 3., Pl. VII., w Thich stage I regard as the early spireme of the spermatogonium. The threads, according to BOLLES LEE, afterwards become shorter and are then definite chromosomes. His figures of this stage are equivalent to my figures 5—6., Pl. VII. BOLLES LEE'S statements have already been criticised by MEVES (72). After the opinion of this latter investigator the stage, in which according to BOLLES LEE the chromosomes spread in the nucleus, is equal to the thin spireme, which here, as everywhere, precedes the thick spireme, i. e. BOLLES LEE changed these two stages. It is indubitable that BOLLES LEE gave an incorrect description of the division of spermatogonia, because these phases which he regarded as those of the division of spermatogonia, do not represent the first phases of their division but those of the first spermatocytes. But BOLLES LEE is certainly right when stating that the chromosomes split and spread through the nucleus. This stage is not the same as the thin spireme, as MEVES believes, it is figured by BOLLES LEE on Fig. 11., Pl. I., by me on Fig. 3., Pl. VII. 2. The spermatocytes. The young spermatocytes are very small, never larger than the spermatogonia, and consist of a relatively very large nucleus and a small amount of cytoplasm (PI. ATI., Figs. 8 —10.). The resting nucleus is filled by a linin network in the threads of which the chromomeres are suspended ; we find the largest masses at the cross points. The primary spermatocytes always have a considerable nucleolus. It is unknown bow long they remain in this resting stage, but till the next stage of development neither the cell itself grows perceptibly, nor does the relation of the size of nucleus and cytoplasm change. This stage is to be seen on Fig. 11., PI. MI., which shows a cell in the earliest phase of division, when the chromatin begins to arrange itself in threads, i. e. 20*
