Z12 MEAD. 
EXPLANATION OF PLATE XVI. 
Unfertilized ovarian eggs. Except where otherwise stated, the figures are 
drawn from single sections. 
Fic. 1. Transverse section of ovarian tubule, showing relative size, position, 
and color of ova in different stages of development, a—-&. Paranucleus in c-g. 
Beginning of formation of asters in 7 and 7, which are well developed in £ ; ¢f.0., 
outer epithelium of ovary ; ¢f.z. inner epithelium. 
Fic. 2. Small ovarian eggs, a and é of Fig. 1; same scale of magnification as 
rest of figures. 
Fic. 3. Compare with stage f of Fig. 1; pav.z., paranucleus ; z., nucleolus. 
Fic. 4. Last traces of the paranucleus. 
Fic. 5. Slightly later stage than Fig. 4. Paranucleus has become completely 
resolved into the cytoreticulum; compare 4, Fig. 1. 
Fic. 6. The cytoplasmic network beginning to form small asters. On the 
right the pellicle is torn away from the rest of the reticulum. Compare and, 
Fig. 1. 
Fic. 7. Numerous secondary asters at the height of their development. 
Compare &, Fig. 1. 
Fic. 8. The two predominant primary asters with centrosomes. Beginning 
of the inpushing of nuclear membrane. Several small secondary asters’ still 
visible. 
Fic. 9. Egg with only the two primary asters; each with a clear centrosome, 
(dark brown). Distinct inpushing of nuclear membrane. Eggs at this stage are 
no longer attached to the ovary. 
Fic. 10. First maturation-spindle lying on the surface of the nucleus ; nuclear 
membrane dissolved. Chromosomes and nucleolus outside the spindle ; centro- 
somes in each aster doubled and smaller than in Fig. 9. 
Fic. 11. Side view, similar to Fig. 10. Remains of germinal vesicle in 
middle of egg. The chromosomes, which appear in the drawing to be in the 
midst of the spindle, are seen by focusing to lie above the central spindle. In 
the right-hand aster only one centrosome is visible; the other is probably 
directly below it. 
Fic. 12. Later; the spindle has swung around to a vertical position; z., 
nucleolus; c#., chromosomes. Both centrosomes are visible in the inner aster, 
one lying almost underneath the other, and therefore farther apart than they 
appear in the figure. The last remnants of the nucleus nuc. 
Fic, 13. Chromosomes of more definite shape and more evenly distributed 
around the equator of the spindle. Spindle more elongated and nearer the 
periphery of the egg. Remains of nucleolus on the left. 
