SUBJECT INDEX
287
Yolk (contd.)
during formation, 241-242
origin of cells or nuclei from, 256-257
physical structure, 225-231
post-hatching fate of, 265-266
sac, 250-260
as transitory liver, 259-260
differentiation, after fourth day, 257258
ingestion of yolk by, 258-259
Yolk (contd)
origin, 250-256
amoeboid movement theory, 253256
periblast theory, 252-253
post-hatching fate of, 265-266
spheres, formation, 234-236
physical structure, 226-228
vitelline membrane, 219-222
weight, 222