1 12 Campbell . — The Embryo- Sac of Peperomia. 
that the cell-cavity is not closed, as Johnson describes (Fig. 13). 
The inner layer of integument-cells has the internal walls 
strongly undulated, so as to crowd and distort the outer layer 
of cells of the nucellus, which Johnson describes as belonging 
to the integument, supposing apparently that the darkly 
stained inner layer of cells of the integument was simply the 
much thickened cell-wall, belonging to what was really the 
outer nucellar layer h The real condition is readily seen in 
the younger fruits (see Figs. 12, 13). 
Summary of Results. 
1. All species of Peperomia seem to agree in having 
regularly sixteen nuclei in the embryo-sac instead of the 
eight normally present in other Angiosperms. There is no 
trace of the marked polarity usually observed in Angiosperms. 
2. One of the nuclei in the micropylar end enlarges some- 
what, and there is an accumulation of cytoplasm about it to 
form the egg-cell. From one to three other nuclei are found 
near the egg-nucleus, and these may show a more or less 
evident aggregation of cytoplasm about them, and may per- 
haps be regarded as the equivalents of the synergidae of the 
ordinary egg-apparatus. They take no part in fertilization, 
and their synergidal character is open to question. 
3. Several (usually eight) nuclei fuse to form the endosperm- 
nuclei, but must be considered as the homologues of the 
polar nuclei of the typical Angiosperms. The remaining 
nuclei are scattered, and each develops about it a cell-wall, 
much as do the antipodal cells of many Angiosperms. 
4. The embryo remains very small, and shows no differ- 
entiation when the seed is ripe. 
5. The divisions of the endosperm-nuclei are always accom- 
panied by the formation of cell-walls. 
6. The hard coat of the fruit is mainly formed from the 
innermost layer of cells of the pericarp. 
1 loc. cit., p. 7, Figs. 14, 15. 
