PLATE 7 



EXPLANATION OF FIGURES 



N. indica, second division. X 2000 



97 Side view of metaphase, showing X and Y, one large double chromosome 

 and an asymmetric tetrad. 



98 A, B, C and 99 A, B Serial sections of two entire spindles, showing all 

 13 chromosomes. 



100 A to E The XY chromosomes in side view of the metaphase. 



101 and 102 Polar views of metaphase, showing 13 chromosomes. The three 

 bodies in the center in 102 are parts of XY. 



103 The XY chromosomes in polar view of the metaphase. 



104 Side view of spindle in anaphase, XY in the center. 



105 The XY chromosomes in early anaphase. 



106 The XY chromosomes in late anaphase. 



107 A, B Sister anaphase groups from same spindle, A containing X and B 

 containing Y, otherwise practically identical. 



108 Side view of early telophase, showing X near upper pole. 



109 The X chromosome in side view in telophase. 



110 to 113 Spermatogonial groups, showing 26 chromosomes including five 

 large ones; X is the largest. 



114 and 115 Oogonial groups, showing 26 chromosomes including six large 

 ones; the two largest are the two X chromosomes. 



160 



