FISHER: SEED DEVELOPMENT IN THE GENUS PEPEROMIA 143 
nuclei occupy the four corners of an imaginary tetrahedron (Fic. 
7). The central part of the embryo sac, from this stage onward, 
is occupied by a large vacuole. As’was shown by Brown (4) in 
P. Sintenisii and in P. arifolia, and by Brown and Sharp (5) in 
Epipactis, the nuclei resulting from the first two divisions of the 
nucleus of the embryo sac mother-cell are frequently separated 
by more or less complete rudimentary or evanescent walls (Fics. 
6,8). It is possible that these rudimentary walls are always 
formed following the first two divisions of the nucleus of the 
embryo sac mother-cell, but that they are so evanescent that they 
are not often seen. No case was found in which the wall following 
the first division had persisted until the second division, and the 
walls following the second division, so far as observed, always 
disappeared before the third division in the embryo sac. 
Each of the first four nuclei divides, thus giving rise to eight 
nuclei (Fic. 9), which are scattered in the peripheral layer of 
cytoplasm surrounding the large central vacuole. No signs of 
separating walls were seen at this stage. 
Each of these eight nuclei divides, thus giving rise to sixteen 
free nuclei in the embryo sac, distributed in the same way as 
were the eight (Fic. 10). Soon after this stage is reached, a 
portion of the cytoplasm near the micropyle, together with a 
nucleus, is cut off by a wall from the rest of the sac, and becomes 
the odsphere or egg (Fics. 13, 14). A smaller portion of the cyto- 
Plasm very near the egg, together with a nucleus, is cut off by a 
wall and becomes a synergid, the only one formed in the sac (Fic. 
14). It is probable that the egg and synergid arise from sister 
nuclei, but no definite evidence of this was seen. Of the remain- 
ing nuclei, a number varying from six to eight in different embryo 
Sacs is cut off singly from the rest of the embryo sac by saucer- 
shaped walls (Fic. 13). A small portion of cytoplasm is cut off 
with each of these nuclei. These peripheral nuclei, as they were 
called by Johnson (30), take no further part in development and 
finally degenerate, being crushed by the developing endosperm. 
The remaining nuclei, varying from six to eight in different embryo 
Sacs, become grouped together, usually near the center of the 
embryo sac (Fic. 11), and fuse to form the endosperm nucleus 
(Fic. 12). The number of nuclei taking part in the formation 
