44 
W. E. AGAE. 
Figs. 25-28. — Stages in the second pairing of the chromosomes. 
Fig. 25. — Twenty-six unpaired univalents, six bivalents, in three of 
which (bl-bS) pairing is complete ; the other three ( b4r-b6 ) have united by 
one end only. Nucleus intact, in 40 n celloidin section. Corrosive-acetic. 
Fig. 26. — Two views of the same nucleus, obtained by turning over 
the section (mounted between two coverslips) and drawing from both 
sides. In each figure all the chromosomes are shown, but those in the 
upper optical section are shaded, and those in the lower half shown only 
in outline. b, a complete bivalent ; 1 and 3. 5 and 6, 7 and 8, 9 and 10 
pairing chromosomes ; 2 and 4 are probably the large chromosomes. 
Untouched nucleus in 40 p celloidin section. Corrosive-acetic. 
Fig. 27. — Only two univalents left (ul, u 2). fifteen completed bivalents 
in the form of rings, and three (one of them 7. the large pair) united by 
one end only. 40 p celloidin. Flemming. 
Fig. 28. — Pairing complete. Some of the bivalents, to show charac- 
teristic shapes and size differences. Flemming. 
Fig. 29. — Metaphase I, polar view. Corrosive-acetic. 
Fig. 30. — Early anaphase I. Flemming. 
Fig. 31. — Late anaphase I. Spindles rotating for second division. 
Flemming. 
Fig. 32. — A pair of metaphases II. Corrosive-acetic. 
Fig. 33. — Anaphase II. Flemming. 
Fig. 34. — A nucleus which, after passing through stages of the meiotic 
prophase as far as the dissociation of the ex-conjugants. is entering into 
a resting stage instead of proceeding to mitosis. The nucleus is cut in 
two sections, both of which are shown. Thirty-seven chromosomes are 
seen. In addition there was one more lying outside the nucleus, having 
evidently been displaced by the razor. 40 p celloidin section. Corrosive- 
acetic. 
Fig. 35. — '• Resting ” stage more complete. Thirty-eight chromo- 
somes present. This nucleus is just shaved at both surfaces, and two 
chromosomes, one at the top and one at the bottom, have been added 
from the preceding and succeeding sections. 30 p celloidin section. 
Corrosive-acetic. 
Fig. 36. — Part of a similar “ resting ” nucleus from a spermatogonial 
prophase. Corrosive-acetic. 
Fig. 37. — Transition of spermatocyte like that shown in fig. 35 
into an oocyte-like condition. Nucleus not intact, several chromosomes 
being in the next section. Zeiss 3 min. apochr., 12 comp. Corrosive- 
acetic. 40 p celloidin. 
Fig. 38.— Oocyte characters fully assumed, spm. Spermatogonium. 
spc. Spermatocytes I. or. Oocyte. Zeiss D. 2. Corrosive-acetic. 40 p 
celloidin. 
