432 SHaw: Notre ON THE PAPAVERACEAE 
(6) The primine.—The persistent parts of the seed-coats are 
formed exclusively from this tissue. The inner layer is marked 
almost from the first by its richer contents of protoplasm and 
active nuclei (PLATE 15, FIGURE 3). Anticlinal division nearly or 
quite keeps pace with the swelling of the ovule, so that at the 
time of the completion of the egg-apparatus (PLATE 15, FIGURE 4) 
the cells are nearly or quite isodiametric. Shortly after that 
period a great anticlinal elongation takes place and this layer be- 
comes the first in prominenee as it is destined to be in importance 
of all the cell-layers (PLATE {5, FIGURE 5). From an early date 
a sort of cuticular layer is formed on its inner surface where it 
comes in contact with the secundine (PLATE I5, FIGURE 5). The 
cells continue to be well filled with protoplasm and to have promi- 
nent nuclei. About the time when endosperm cells begin to be 
cut out, crystals of calcium oxalate appear within this layer, and 
these later accumulate to a considerable degree. While the endo- 
sperm is maturing, their layer still further increases in size and 
becomes greatly indurated. It forms the most important part of 
the testa, exceeding in thickness all the other layers together 
(PLATE 15, FIGURE 6). 
The middle layer of the primine undergoes both perielinal and 
anticlinal division so that in the later stages it is several cells deep 
(PLATE I5, FIGURES 4, 5,6). All these cells become highly vacu- 
olated, increase in size, and toward the last become compressed by 
the enlarging inner layer of the primine and almost disappear. 
The outer layer of the primine undergoes comparatively few 
divisions and these are all anticlinal. Although the cells become 
much enlarged, they are not distorted by pressure nor in any way 
disorganized, and developing thick walls on every side, they con- 
stitute the outer hard and shining coat of the seed (PLATE 15, FIG- 
URE 6). The caruncle arises just outside the vascular tissue of the 
taphe, and its enormous cells are thin-walled, but by no means 
poor in contents. Despite the ready ecological explanations ad- 
vanced, the significance of this caruncle is still, to the writer at 
least, a mystery. 
In Eschscholtzia the development of the integuments resembles 
that in Sanguinaria, but with the difference that the principal layet 
of the testa is composed of smaller cells which have relatively little 
induration. 
