THE MITOCHONDRIA AND OTHER STRUCTURES. 1 09 



which previously lay along these threads (Fig. 23) and scattered 

 towards the nucleus, have now disappeared. 



During the anaphase of the living cell the daughter chromo- 

 somes move to the extreme proximal pole of the cell and when the 

 cytoplasm constricts, the continuous mitochondria threads again 

 become granular and from the ends of these threads the mito- 

 chondria granules migrate away towards the two groups of 

 chromosomes (Fig. 22). In some instances the entire mitochon- 

 dria thread appeared to pass over to one daughter cell, but usually 

 the division of the mitochondria took place by means of the 

 migration of the granules into each daughter cell, so that each 

 daughter cell received about the same amount of mitochondria. 



When the preparation was stained with Janus green the mitotic 

 division continues, provided it was started before the stain acted 

 upon the cell (Figs. 17-20), but after the division was finished, 

 the cell did not pass through the second spermatocyte division 

 as the unstained cells did. The mitochondria threads become 

 granular and do not usually extend from chromosome group to 

 chromosome group, but more frequently lie in a broad band 

 around the equator of the spindle (Figs. 16, 17, 18 and 19). The 

 ends of the granular threads swell up and become varicose before 

 the granules migrate away (Figs. 19 and 20). 



Second Spermatocyte (Inter kinesis}. After the mitochrondria 

 have migrated into the daughter cells the cytoplasmic bridge 

 between the two cells remains and elongates. The cells may 

 sometimes remain thus attached by a long process during the 

 semi-resting condition (interkinesis), which may continue for an 

 hour or even for several hours before the cells prepare for the 

 second spermatocyte division. The second spermatocyte has a 

 characteristic appearance and is easily recognized. The chro- 

 mosomes remain and it can be seen that they are no longer 

 tetrads as they were in the first spermatocyte (Fig. 30). The 

 mitochondria are gathered into an irregular body at one side of 

 the cell and from this body the mitochondria granules spread 

 out somewhat toward the nucleus (Fig. 30). 



Second Spermatocyte Division. The behavior of the mitochon- 

 dria during the second spermatocyte division is practically the 

 same as that during the first spermatocyte division. In this 



