Studies on Chromosomes. 



529 



/ 



T: f 





 . 







/ 



w */ 







V, 







FIGURE 4. 



Banasa calva. a, b, Metaphase-figures, first division, in polar view, showing fifteen chromosomes, 

 including two small ones (ft, heterotropic chromosome, /', small idiochromosome the large idiochro- 

 mosome not distinguishable); c-g, successive stages of first division, in side-view, showing division of 

 the small idiochromosome ('), and the unipolar movement of the heterotropic chromosome (A); h, meta- 

 phase-group of second division, with thirteen chromosomes; , metaphase-group of the same division 

 with fourteen chromosomes; _/-/, metaphase and early anaphase of second division, showing separation 

 of the idiochromosomes, and equal division of the heterotropic chromosome; m, sister-groups from the 

 same spindle, early anaphase second division, fourteen-chromosome type; n, similar pair, late anaphase; 

 o, similar pair, middle anaphase, thirteen-chromosome type; p, q, entire chromosome-group from a 

 single nucleus at the end of the growth-period, showing idiochromosome-dyad (;') and heterotropic 

 chromosome (h\ 



