PLATE 3 



EXPLANATION OF FIGURES 



Notonecta insulata 

 X2250 



25-26 Metaphase of first division, polar view, showing 14 chromosomes, two 

 small ones in center. 



27-28 Same with 13 chromosomes, one small one in center, 



29-31 A, B, C Serial sections of entire spindles in side view, showing one small 

 pair in center, and compound chromosome Ma, consisting of largest chromosome 

 and second small one. 



32 Polar view, showing same. 



106 



