Various

“ In 1897 he called the collection of granules around the centrosome, the centrodeutoplasm. He considers them to be identical with St. George’s cytomicrosomes and the archoplasm (or attraction sphere) of other writers. In order to harmonize results, he suggests that, since the centrosome sometimes wanders around the nucleus, the centrodeutoplasm (or sphere) may unite with the spindle remains in some cases to form one body, as shown by the descriptions of Henking, Henneguy, Meves, and others. He later (’97, 2) describes the so-called “sphere,” and distinguishes between it and the true nebenkern. ”

“ I have not followed the centrosome through its migrations. In fig. 2 one of the two bodies is the centrosome, but I did not trace its changes farther.
5.—Cell Body.
The cells, up to the stage of figs. 13 or 14, have been scattered promiscuously through the cyst; but as the cell begins to elongate, the one end becomes the anterior-nuclear end, and it shifts to the periphery of the cyst. The central part of the cyst now shows the so-called central lumen. As the lengthening goes on the heads of the forming spermatozoa are all turned toward the distal end of the cyst. ”

“ Here we have the darkly staining central ball surrounded by a clear space, enclosed by a ring, as Meves (’00) found it in Pygæra. The central ball sometimes shows vacuoles (fig. 16) , but most frequently stains as one mass. In some cysts with cells resembling fig. 16, it is difficult to distinguish between nucleus and nebenkern, yet the latter’s stain is never as intense as that of chromatin. The stages shown in figs. 13 and 14 persist for a long time, and it is probable that this is the end of the telophase and the beginning of the spermatid transformations. ”

“ These spaces collect and unite into larger vacuoles, which surround the darker center. Finally there is only a dark ball with a surrounding clear space shut in by a ring. The centrosome with attached axial filament fastens itself to the nucleus; then both begin to grow longer. The axial filament passes over the surface of the ring surrounding the ball—the “mitochondrion körper” or nebenkern. This body elongates a great deal then the darker mass puts forth numerous threads which surround the axial filament. ”

“ Again, Platner (’89, 1) probably followed the centrosome and attraction sphere, as well as the nebenkern, in the second part of the paper on Helix and Paludina. In the pancreas the body is a result of secretion, and is not a nebenkern. In Pygæra Platner’s large mitosome is the real nebenkern, as shown by its fibrous structure, its surrounding clear space and destiny. His small mitosome is what I have described as the acrosome, and he is mistaken as to its final use. The body he called centrosome in the nucleus is the persisting accessory chromosome. ”

“ The nebenkern is in the ball-and-ring stage. The acrosome shows its characteristic clear center surrounded by a ring darker on one side. The two dark bodies on the nuclear surface are probably artefacts.
Fig. 14. A stage a little later than 13. The dark central ball shows some vacuoles. The cell is beginning to elongate.
Fig. 15. Same as fig. 14, with the ball denser.
Fig. 16. The nucleus has become almost clear. The acrosome is behind the nebenkern.
Fig. 17. This shows the axial filament apparently growing out from the nucleus. There is an aggregation of chromatin at its base. ”

“ Hier sind ihre Grenzen undeutlicher, verwaschen und zeigen hier auch noch häufig eine streifige Beschaffenheit, welche auf ihren Ursprung hin weist. Zuweilen lassen sich einzelne Fäden noch eine beträchtliche Strecke weit in das Protoplasma hinein verfolgen, welches zwischen ihnen und den sich ausbildenden Zellkernen liegt. ”

“ However, he described an oval body which he found varied in appearance, depending on the method of fixation. He calls it the “nebenkern” and thinks it goes to help form the tail.
The description is too incomplete for comparison. Judging from Gryllus, I question its being very poor material. [56]
Bütschli (’71) studied the spermatid transformations in Acrididæ and Locustidæ along with that of other animals. He saw the object formerly described by St. George and named it “nebenkern.” He saw it divide into halves, elongate, and form the spermatozoon tail. ”

“ For a long time it contains the many chromatin granules, as seen in figs. 39, 40, and 41; but at last the walls seem to attract all these granular masses, and the center is entirely clear, as in fig. 45. In fig. 44 are shown cross-sections of spermatozoa heads, of the stage of fig. 43. In fig. 45 we have a mature spermatozoon head.
The accessory chromosome in Gryllus lags behind during the spermatogonial divisions, just as in Xiphidium (McClung, ’99) , and retains its identity all through the growth period, in many cases becoming quite large. ”

“ This may be due partly to poorer fixation in other mixtures and partly to chance, as not so many testes fixed in other agents were examined, and the appearance evidently represents a very brief stage. These fibers now begin to break up, and we get figures that remind one of Meves’s “mitochondrion körper”; that is, a darker staining center and radiating lines to the outer ring. (Fig.11.) Sometimes stages a little later recall Paulmier’s “blackberry stage.” (Figs. 12 and 25.) Fig. 19a is a surface view and fig. 19b an optical section of a nebenkern that is in the process of breaking up. ”