Amitosis in tke Ovary of Protenor belfragei and a Study of tlie Cliromatin Nucleolus. 229 
Photo 13. A group of 14 chromosomes from one of the large nuclei of zone B 
of an ovary removed from an immature insect about one half grown. The ovaries 
from such immature insects are. as a rule, slightlv tinged with yellow and the ovarian 
tubes are about one third smaller than one of the terminal chambers of a mature 
ovary. We find no egg chambers in these immature ovaries, but we do find young 
germinal vesicles developing in zone C. 
Photo 14. A group of 14 chromosomes from the same area of the same ovary 
as the group demonstrated in photo 13. 
Photos 15 — 18. Chromosome groups from the terminal chambers of a mature 
ovary. The insect from which this ovary was taken had been kept in the laboratory 
three days and during this time had deposited several eggs. 
Photos 19 — 24. Nuclei from zone B of the terminal chambers of the same ovary 
from which the chromosome groups of photos 15 — 18 were selected. 
Plate XVI. 
+ 1000 . 
Photos 25 — 35. Nuclei from terminal chambers of mature ovaries. Photo 25 
shows a large nucleus fragmenting into small pieces. (The section demonstrated in 
photo 2 shows this same phenomenon at the base of zone B.) Photos 26 and 27 
demonstrate that large free nuclear fragments, such as those shown at the left of 
photo 25, the right of photo 30 and in photo 31, may develop without further frag- 
mentation, ultimately forming groups of relatively large chromosomes. Wliereas small 
nuclear fragments, such as those shown in the centre of photo 25, and in photo 32 may 
develop into smaller chromosome groups, as shown in photos 28, 29, 30, (left) 33, 34 
and 35. In most of these nuclei the chromatin nucleolus is a single bodv, while in 
others it is double. 
Photos 36 — 43. A few cells from the testes of mature males, reproduced to 
compare with the ovarian cells. + 1000. 
Photo 36. A spermatogonial group of chromosomes. 
Photos 37 — 42. Spermatocytes with the chromatin nucleolus as a rod, a ring 
or two spheres. 
Photo 43. A first spermatocyte prophase group of chromosomes. 
Plate XVII. 
+ 1000 . 
Photos 44 — 57. Are preparations from an ovary from a larval insect, before 
the appearance of the wing pads. This ovary was exceedingly small and faintly tinged 
with yellow. 
Photo 44. Shows an early Segregation of the chromatin into a chromatin nucleolus 
and photos 45 — 55 show further development of the nuclei and various morphological 
phases of the chromatin nucleolus. 
Photo 56. This preparation suggests that the two long chromosomes, character- 
istic of the chromosome groups found in the female may be evolved from the chromatin 
which at the earlier stages forms a typical chromatin nucleolus. In one of the nuclei 
of photo 47, and in the nucleus of photos 52 and 54 a second small chromatin nucleo- 
lus is present. 
Photo 57. A group of chromosomes showing the number and the size rela- 
tions characteristic of the female. 
