Hybridization of Ec/iinoids. 25 



During division the yolk and oil droplets seem forcibly pushed out 

 of the region of the amphiaster, which Ues in a region of clear cyto- 

 plasm. As the cell passes into the telophases of division the yolk 

 and oil droplets are carried inward and again lie distributed uniformly 

 through the cell. 



\>i\N ^fl\\] /l/iS 



8 



Fig. 8, a, b, and c. Three successive sections of a first-cleavage 

 amphiaster. One heterotypic chromosome, 32-32. 



i/"\ "Vim '^^''A 



/ 



I 



€t b c 



Fig. 9, a, b, and c. Three successive sections of a first-cleavage 

 amphiaster. Two heterochromosomes. One chromosome 

 divided and lagging at the center. In the anaphase plates 

 32-32. 



The chromosomes divide and move apart with great regularity; 

 lagging chromosomes are seen only rarely (figs. 9a and 96). Figures 

 6, 7, and 9 are of anaphase plates showing two of the double-armed 

 rods in each plate of chromosomes; in figures 8 and 10 but one of these 

 chromosomes of double width could be found. In figure 11a only 

 one section of the spindle is shown; in this egg no chromosomes of 

 double width could be found; there is, instead, a chromosome of 



