Miyake, The development of the gametophytes etc. 3 



results and interpretations do not agree, and the opinions still differ 

 among- various investigators. In the present paper I have no In- 

 tention to enter into a discussion of the disputed points; and the 

 min Ute descriptions of these as well as other stages of the re- 

 duction-division are not to be givcn. 



The chromosomes fornied by the segmentation of the spirem are 

 found in pairs. The bivalent chromosomes now become short and thick 

 (fig. 5). With the disappearance of the nucleolus and the nuclear 

 membrane, the formation of the spindle begins. The spindle is at 



Text-fig. 1. Staminate cones ready for pollination, seen from the underside 



of a branch. About X ^Ji- 



first nmltipolar and later assumes the bipolar structure (figs. 6—8). 

 The chromosomes then arrange themselves at the equator of the 

 spindle as shown in figs. 7 and 8. The number of the chromosomes 

 can easily be counted at this stage, viewing from a pole of the 

 spindle. Their number, i. e., that of the bivalent chromosomes, is 

 twelve, as it is usually the case with other Conifers (fig. 9). 



Each of the bivalent chromosomes, which are arranged at the 

 equatorial plate, soon separates into two, and the daughter-chro- 

 mosomes begin to move toward the poles. Very soon the chro- 

 mosomes show the sign of longitudinal Splitting and, as they approach 



1* 



