Dictyokinesis in Germ Cells. 



239 



The divided apparatus is shown in fig. 15. In fig. 17 is seen a metaphase 

 stage, the Golgi elements scattered in the cytoplasm appear as annular 

 bodies composed of two semi-lunar rods. Mitochondria have been drawn 

 in this figure as they appear in preparations counter-stained with Altmann's 

 acid fuchsin. During the telophase, when the chromosomes are completely 

 drawn apart, the dictyosomes are attracted once more to the astrosphere. 

 Their movement towards the astrosphere at this stage is shown in fig. 18. 



The second spermatocyte division takes place in exactly the same manner 

 as the first. The divisions of the archoplasm, and its movement to the 

 opposite ends of the cell during the prophase, appears to take place with 

 considerable rapidity, as very few cells are found in these stages, and it will 

 be seen from the figures that but little change occurs in the chromosomes 

 during fission and separation of the archoplasm. 



Division of the Chromatoid Body in the Mammals Mus and Cavia. 



At the same time as the Golgi apparatus of the mammalian spermatocyte 

 is in process of division, the chromatoid body breaks up into two equal 

 parts. This process is best seen in the Weigl-Kopsch preparations of Cavia, 

 in which, after staining with acid fuchsin, the chromatoid body appears 

 coloured similarly to the mitochondria. In fig. 13, which shows the 

 beginning of dictyokinesis in the primary spermatocyte of Cavia, a single 

 large chromatoid body (CB) is seen. In fig. 14, where the archoplasm 

 appears very nearly divided into two parts, the chromatoid body has 

 divided, and the two parts are just separating. They are further apart in 

 fig. 15, while, in the metaphase stage shown in fig. 17, they occupy positions 

 on opposite sides of the chromosome group. A similar stage in the 

 spermatocyte of Mus is shown in fig. 4. At the telophase, the two 

 chromatoid bodies become separated ofi" into the newly forming cell, as is 

 happening in fig. 18. Consequent upon the repetition of this process in the 

 second spermatocyte division, each spermatid has a single chromatoid body 

 directly derived from that of the spermatogonium. 



Dictyokinesis in Molluscs. 



The fundamental nature of the dictyokinesis in the germ cells is shown by 

 the similarity of the process in animals so widely apart in their systemic 

 position as the MoUusca and Mammalia. 



At fig. 19 is drawn a primary spermatocyte of Helix as it appears in 

 riemming-without-acetic preparations, stained by iron alum haematoxylin. 

 The chromosomes have reached their diakinetic stage, and mitochondria, 

 which previously were rounded, have metamorphosed to form rodlets. 



