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SHaw: NOoTE ON THE PAPAVERACEAE 431 
podals acquire thickened walls (PLATE 15, FIGURE 1). This tissue 
increases during the enlargement of the sac and the formation of 
the endosperm. It can scarcely be doubted that to this tract, 
together with the enlarged antipodals, some nutritive significance 
attaches. 
The size of the nucleoli is noteworthy both in the nuclei of the 
embryo-sac and those of the surrounding cells. Practically all of 
the strongly staining substance of the nuclei is included in them. 
It is difficult to entertain any other idea than that these nucleoli 
embrace the chromatin. 
DEVELOPMENT OF THE SEED-COATS IN SANGUINARIA 
The integuments arise shortly after renewal of growth in the 
spring as two folds growing up around the nucellus. Each con- 
sists throughout most of its extent of three cell-layers (PLATE 15, 
FIGURE 3). Following is a description of the differentiation and 
destiny of each of these: 
(@) The secundine.—The inner of the three cell-layers under- 
goes anticlinal division as the ovule enlarges, so that at the time 
when the egg-apparatus is formed the cells are still nearly isodia- 
metric (PLATE 15, FIGURE 4). At this time they have the appear- 
ance of active cells with abundant protoplasm and well-developed 
nuclei. Very soon, however, their anticlinal division becomes less 
active and at the same time they are stretched by the expanding 
embryo-sac. By the time that the endosperm nuclei have spread 
to the wall of the embryo-sac this layer is losing its organization, 
and thereafter appears only as an ill-defined rudiment (PLATE 15, 
FIGURES 5 AND 6). 
The middle layer of the secundine has almost from the first 
less protoplasmic contents. At the time of the completion of the 
€gg-apparatus it appears highly vacuolated with larger cells and 
degenerating nuclei. This is the first of all the layers to break 
down, the cells losing their form shortly after fertilization. 
The outer layer of the secundine does not become vacuolated 
to so great a degree as the one last named and it persists some- 
what longer. But it shares the fate of the other layers of the 
secundine, appearing while the endosperm is forming only as a 
mass of distorted and fragmentary cell-bodies. 
