THE SPKRMATOGENESIS OK IMHKA I.1MI. 129 



stage at one side of the two main chromatin mus-i - near the 

 nuclear membrane. These two rings are connected by a thin 

 strand of dm MD, it in material. They apparently lose their 

 identity in the following stage. Fig. 28 shows a further con- 

 traction phase. In this stage the chromatin masses at each 

 pole draw away from the nuclear membrane and collect toward 

 one side of the nucleus. Fig. 28 shows the remaining portion 

 of the smaller mass being incorporated into the main mass. 

 This marks the end of the period of synizesis. 



Immediately following synizesis the nuclear membrane dis- 

 appears. Fig. 29 shows the unravelling or breaking up of the 

 chromatin knot into bars and smaller masses of chromatin. 

 At this point eleven irregular chromatin bodies corresponding 

 to the reduced number of chromosomes can be recognized. Figs. 

 30 and 31 show a further unravelling of these knotted masses 

 or bars of chromatin. Rings or loops are to be seen appearing 

 from the denser masses as shown in Fig. 29. These stages (Figs. 

 29 and 30) mark the final passing of the stage of synizesis. 



The rings of chromatin which are to be seen in late diakenesis 

 appear to be derived in two ways from the synizesic mass: 

 (i) Long threads of chromatin segment after the unravelling 

 of the previous stage and may be seen in twos (Fig. 61 n and o) 

 one wrapped around the other, having the appearance of a 

 definite strepsinema which might permit of a "double or triple 

 cross over." Typically these threads apparently unwrap, how- 

 ever, and later condense into rings, each pair constituting such 

 a ring. (2) Shorter segments may be seen in early stages 

 following synizesis which arrive at the ring stage by a sort of 

 unravelling or pulling apart as shown in Figs. 32 and 33, and 

 (a) and (6) of Fig. 61. This pulling apart appears to take place 

 at the ends first and later, a space appears between the two 

 threads at the middle (Fig. 61 c, d, e, /) ; the ends having come 

 into contact again. 



Figure 61 (a) to (p) shows various diakenetic figures in the 

 contraction and formation of the rings; these may have been 

 derived from either condition previously described. Figs. 31 to 

 35 show various stages in the formation and further contraction 

 of these rings. In Fig. 34 several chromatin figures in the form 



