270 BOTANICAL GAZETTE [APRIL 
Fic. 15. Definitive nucleus nearly complete, with a pair of fused centro- 
spheres on opposite sides ; the two nucleoli are still distinct. x 600. 
Fic. 16. Definitive nucleus with three nucleoli distinct, and two centro- 
spheres on opposite sides. * 600. 
Fig. 17. Definitive nucleus with two large nucleoli apparently fusing. x 
00. 
Fig. 18. Definitive nucleus with one small nucleolus and two large fusing 
nucleoli. X 600. 
Fic. 19. Embryo sac showing one synergid, the oospore, the definitive 
nucleus, and two antipodals ; the definitive nucleus has but one large nucle- 
olus. X 600 
Fig. 20. Upper end of an embryo sac, showing the arrangement of the 
egg apparatus. X 600. 
Fic, 21. Upper end of embryosac with pollen tube entering; the oosphere _ 
nucleus with two prominent centrospheres. X 600. 
Fig. 22. Upper end of an embryo sac with pollen tube; one sperm 
nucleus in the tip of the tube preceded by two centrospheres. X 600. 
Fic. 23. Pollen tube with a sperm nucleus at the tip preceded by two 
centrospheres. X 600. 
PLATE XX. 
Fic. 24. Upper end of embryo sac with pollen tube; two sperm nuclei 
in the tube, the one at the tip. preceded by two centrospheres. < 600. 
FiG. 25. Embryo sac with definitive nucleus, one antipodal, one syner- 
gid, oosphere, and pollen tube with two sperm nuclei; several granules 
between the oosphere nucleus and the sperm nucleus at the tip of the tube. 
x 
Fic. 26. Upper end of embryo sac with pollen tube. * 600. 
Fic. 27. Upper end of embryo sac; the lower sperm nucleus is just leav- 
ing the tube, and between it and the oosphere is a mass of granular proto- 
plasm. xX 600. 
aes tes ees end = ays sac; the sperm uyclews with prominent 
and is approaching the oosphere. X 600.. _ 
Fic. 29. Part of an patied sac with definitive nucleus, oosphere, and 
pollen tube; the oosphere nucleus is greatly bulged out on the side toward 
the sperm nucleus; sperm nucleus just leaving the tube. X 600. 
Fi. 30. Upper end of embryo sac; the sperm nucleus has just left the aS 
a EE at the tip from which protoplasm is ae 
sete areas tee ~~ — 
"pollen tube, which shows a pe 
sie aU x mi) 
