22 J- E. WODSEDALEK. 



It can now be clearly seen that great variation exists in the 

 amount of fusion which takes place in the chromatin material 

 of the various cells in this stage of the maturation process. In 

 some cells fully eight times as many chromosomes pair as in 

 others. The question at once arises why should such a decided 

 variability exist in this respect. It is not very probable that the 

 various cells resulting from the last spermatogonial divisions 

 differ so greatly in their make-up, as no such variability was 

 observed in the spermatogonial cells themselves. The fate of 

 the different primary spermatocytes with respect to the extent 

 of pseudo-reduction of their chromatin material is evidently 

 determined at the time of the formation of the network of the 

 linin threads, for these linin threads seem to persist as the axes 

 of the later chromatin threads which eventually break up into 

 chromosomes. 



The nature of the cause of the linin strands connecting with 

 each other in such confusion as they are found, must necessarily 

 remain a matter of conjecture at present. The same force which 

 in normal sex cells at this stage causes the linin strands to come 

 in contact at their free ends, thereby forming long threads, or 

 loops, or a continuous strand, is apparently brought into action 

 in the hybrid cells but not with the same precision. The fact 

 that the two plasmas are so different apparently causes the 

 strands to connect with each other at any point and at any angle, 

 instead of at their free ends only, and thereby forming a con- 

 tinuous network rather than long strands. The tendency of the 

 strands to connect with others, however, must be well pronounced 

 for very seldom can any free ends be seen in the earlier stages 

 (Figs. 8 and 9). Later on, of course, free ends make their ap- 

 pearance but these are caused by the breaking up of the network 

 in parts rather than original failure at fusion. In some cells the 

 end to end fusion of the original components is more pronounced, 

 since many long threads appear in such cases. However, not a 

 single case was seen in which several of the cross-connecting 

 pieces were not present, which condition was never observed to 

 occur in the corresponding stages in the sex cells of the horse. 



The fact that the ends of the threads are fused on to some 

 other part of the chromatin network seems to be a drawback 



