EXPLANATION OF PLATES. 
PrATE i. 
Fic. 1. Sectional view of mass of odgonia; cell-boundaries are indistinct. > 2100. 
Fic. 2. Primary o6cyte at the very beginning of the growth-period. Cell-outline indi- 
cated by dotted line. 2100. 
Fig. 3. Slightly later stage, showing decided increase in size of nucleus. > 2100. 
Fic. 4. Still later stage, showing increase in amount of chromatin and the characteristic 
distribution of the same in masses along the nuclear membrane. 2100. 
Fic. 5. Odcyte entering upon the contraction phase (synizesis, McClung). The spireme 
appears to arrange itself in two parallel strands. > 2I00. 
Fics. 6, 7, 8, 9. Nuclei with chromatin threads in more or less complete synizesis. 
Linin network has become indistinguishable. > 2100. 
Fic. 10. Odcyte showing the spireme in complete synizesis. X 2100. 
Fics. II, 12, 13. Odcytes showing the first stages in the disentangling of the spireme 
from the contraction phase. Linin network faintly visible. > 2100. 
Figs. 14, 15. Nuclei showing still later stages in the disentangling of the spireme from 
synizesis. Nucleoli clearly visible. > 2100. 
Fics. 16, 17, 18. Odcytes in which appear the first indications of a transverse segmen- 
tation of the apparently continuous spireme. 2100. 
Fics. 19, 20, 21. Odcytes showing a distinctly beaded character of the now discon- 
tinuous spireme. Occasional segments clearly indicate that the spireme 
has become double. \ 2100. 
Fics. 22, 23. Odcytes with chromosomes in form of beaded threads. A portion of 
the spireme appears still unsegmented and double. 2100. 
Fic. 24. Oocyte in which some of the chromosomes have become condensed into 
irregular masses while others remain as beaded threads. > 1320. 
Fic. 25. Odcyte at slightly later stage, showing all the chromosomes in the form of 
condensed irregular chromatic masses. There are indications of ring, V, 
and dumb-bell shapes. Some of the chromosomes appear paired; all have a 
mossy or feathery outline under high magnification. > 2100. 
IPT ATE 2: 
Fics. 26, 27. Young primary odcytes, showing chromosomes in various stages of trans- 
formation from beaded threads to compact bilobed bodies. Many of the 
chromosomes appear disposed in pairs. > 1320. 
Fic. 28. Odcyte at a somewhat later stage. Attachment to ovarian stroma shown; also 
the enveloping connective tissue membrane. Chromosomes have dumb- 
bell and globular shape. Linin network conspicuous. Cytoplasm densely 
granular and deeply staining with basic dyes. X 1320. 
Fic. 29. Primary odcyte at late stage in growth-period. Chromosomes of irregular 
shapes scattered through the slightly chromatic linin network. Nucleolus 
very large and homogeneous. X 700. 
Fic. 30. Odcyte at stage just before maturation. The chromosomes, gathered into 
a single mass, are connected with the nucleolus by a double chromatic 
thread. X7 
Fics. 31, 32. Odcytes ae the stage just prior to maturation. The chromosome mass 
is in position next the cell periphery. The nucleolus and chromosome 
mass are connected by a chromatic thread. X 700. 
Fics. 33, 34. Odcytes in which the chromosomes are collected in a mass close to the 
nucleolus. The puckering of the nuclear wall shows that maturation is 
imminent. The linin network still achromatic. Chromatin appears to 
leave the nucleolus in the form of drops. > 700. 
Fics. 35, 36. Odcytes showing a connection in the form of a beaded chromatin thread 
between nucleolus and chromosomes. > 700. 
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