THE CHROMOSOMES 



91 



chromonemata in the form of a double-stranded spiral like that of tlic 

 preceding anaphase. 



Meiotic Chromosomes. — The next chapter is to be devoted to 

 chromosome beha\'ior during meiosis, the process by which a reduction 



FiCx. 63. — Four stages in mitosis in microspores of Trillium grandijloium. 1, propliase: 

 twists and relic coils (large gyres) from previous cy(-le still present; small gyres developing 

 in each chromatid. 2, later prophase: new gyres in chromatids now larger and fewer. 3, 

 metaphase. 4, anaphase. See text and Fig. 62. P>om temporary acetocarmine smears. 

 {After A. H. Sparrow.) 



in the number of chromosomes is accomplished at a certain point in the 

 life cycle. In the present section we shall merely review a few facts 

 that will serve to complete our description of fundamental chromosome 

 structure. 



