14 INTRODUCTION PROTOPLASM THE CELL 



species, it is fixed and unchangeable. In man the number of 

 chromosomes is sixteen. 



The termination of the prophase is marked by the approach of 

 the chromosomes toward the equator of the achromatic spindle. 



Metaphase. The chromosomes now come to lie in the equator 

 of the achromatic spindle, and are so arranged that each segment 

 forms a U or V, whose apex is directed toward the axis of the spin- 

 dle. When viewed from the nuclear pole, this peculiar arrange- 



a 



FIG. 14. EPIDERMIS OF THE SALAMANDER. Three cells are in process of division by 



mitosis. 



o, prophase ; 6, inetaphase. The second cell above 6, whose cell body is in process of 

 fission, presents a stage of the telophase. (After Wilson. ) 



ment of the chromosomes produces a wreath-like appearance, the 

 monaster. 



The chromosomes now divide by longitudinal cleavage into 

 two exactly equal portions, which promptly begin a migration 



