Horváth Géza (szerk.): A Magyar Természettudományi Múzeum évkönyve 8. (Budapest 1910)
Soós, L.: A Helix arbustorum hím csirasejtjének fejlődése
310 LH L. SOÓS It was described in Helix first by PLATNER, and since then many authors have found them in different forms. PLATNER named it with a term given B}' B ÜTSCHLI nebenkern which term has since then been very often used. This organ can appear in very different forms even in the same sort of cells according to the different stage of its development, therefore it has been named variously by different authors. H EIDENHAIN called them pseudochromosomes, MEVES chondriomites, or mitochondria. GOLDSCHMIDT (32) is of the opinion that this organ is identical with the chromatic apparatus described by R. HERTWIG from the Protozoa, and POPOFF (94) accepted GOLDSCHMIDT'S suggestion. It seems that the interzonal body of the American authors belongs partly to it. The Figs. 1., 3. and 4., Pl. VHI., which were drawn from preparations fixed with BOUIN'S picric-formol either do not show this cell-organ, or do so very insufficiently, because this mixture, as mentioned above, is not well adapted to preserve it. It is, however, very clearly visible on Fig. 2., Pl. VIII., drawn from a FLEMMING preparation. This figure, though it shows a later stage in development, yet, in spite of this, exhibits the connection of the cromosomes and nebenkern. This connection is so regular that we must suppose a closer relation between the chromosomes and nebenkern. POPOFF (95) interpreted this connection as follows : The nuclear sap is during synapsis continually increasing, in consequence of which the nuclear membrane swells. At length the membrane cannot balance the pressure and at its weakest part breaks through. Through this opening fluids diffuse from the nucleus to the cytoplasm which also seizes minute chromatin corpuscles, and these latter build up the chromatic appai'atus. The stream also seizes the open ends of the chromosomes, therefore they become loop shaped, and their ends become naturally attached to the nuclear membrane. The chromatin condenses in spherical cliromomeres arranged regularly in the linin of the loops, they are thus rosary shaped. The cliromomeres are connected rather loosely, therefore the chromosomes often disintegrate into their constituent parts. The chromosomes in the next stage split (Pl. VIII., Fig. 1.). The half threads like the whole ones consist of spherical chromomeres. They are always arranged symmetrically side by side in pairs in the achromatic ground substance. I have never found split chromosomes having alternated chromomeres; POPOFF (94) made the same observation in Paludina. The chromosomes synchronously with their splitting scatter through the nucleus, while the daughter chromosomes separate from each other, as is seen on Figs. 1. and 3., Pl. VIII., the former showing an earlier,
