220 KIYOSHI MASUL 



gi'auules appear iu small numbers wliicli are iisirally gathered near the idio- 

 zome (Figs. 98, 99). 



The pachytene stage: — The number of spiremes is considerably reduced, 

 apjxjariug about half of the original number and fully twice a3 many as those 

 of the loptotune stage (Fig. 100). The movement of the chromatin spiremes 

 are can-ied out fiu-thcr imtil they spread throughout the nucleus, while the 

 cell gradually increases in size and the nuclear wall is more clearly defined 

 (Figs. 101, 148). In this stage two or more small spherical nucleoli appear, 

 wliich can cleai-ly be seen in the section stained with Aüerbach's method 

 (Fig. 148). 



The diplotene stage : —The cells rapidly gi-ow in this stage, becoming 

 twice as large as iu the leptotene stage, and the spiremes stain faintly with 

 irou-hasmatoxyliu, and show a granular appeai-auco (Fig. 101). Together 

 with the gTowth of the cell the spiremes Ijecome thicker, and iu some 

 spiremes the lougitudiual splitliing appears distiuc!;ly iu any preparation 

 (Figs. 102, 103). The spiremes shorten more and more until the varioiLS 

 bivalent chromosomes appear (Fig. 104). 



As in the mouse in this stage the spiremes increase the affinity for acid 

 fuchsin, which proceeds jDarallel with the gi'owth of cells, attaining its 

 maximum at the end of this stiige (Fig. 150). 



The nucleolus is conspicuous throughout this stage, and attains its gi-eatest 

 size at the end of this stage (Figs. 149, 150). As in the mouse the chromatoid 

 body appears at the beginning of this stage, being stained like the nucleoli 

 (Fgis. 102, 105, 150). 



Dm-ing this stage the chromosome nucleolus which coiTC-sponds exactly 

 witli that of the horse can bo clearly soon (Figs. 101-103, 150). 



The prophase : — Finally the spiremes become shortened in length and 

 form many variously cm-ve<l chromosomes, but the forms of the bivalent 

 clu-omosomes are different from those of the mouse (Fig. 105). In some 

 clu-omosomes the longitudiual sphtting-s are very conspicuous, and form large 

 slits in the chi-omosomos (Fig. 104). Thus the ring-shaped chromosomes 

 ap^xjar, while iu most of the smaller clu'omosomes the longitudinal splitting 

 does not appear at all but the clu-omosomes aii^xjar as bivalent rods (Fig. 

 105 .\ 



