282 Ewart. — On the Leaf -glands of 
close similarity with the glands of Nepenthes. Macfarlane states 1 
that f in the formation of the alluring perithecioid glands of 
leaves, and in similarly shaped glands of some lids, an evident 
epidermal depression in the region of the future gland appears 
about the time that division in its cells is beginning. Owing 
partly to rapid division and growth of the marginal gland- 
cells, but specially to similar activity in the surrounding 
epidermal cells, these last rise up round the central gland- 
mass and cover it in until only a small circular or elliptic 
aperture is left in the middle of the covering-in cells.’ And 
again, ‘there is a decided tendency in many species to sinking 
and infolding of the gland with restriction of the exposed 
surface, but in N. Pervillei this is carried to such an extent 
that each gland opens by a very narrow elongated orifice.’ 
Development of the Secretory Epithelium. In the earliest 
stages of the gland (Fig. 6) the lumen is lined with ordinary 
merismatic epidermal cells, which, however, are crowded 
closely together and have conspicuous nuclei. Fig. 7 repre- 
sents the left-hand gland and duct of Fig. 6 more highly 
magnified; and Fig. 11 a small portion of the epithelium 
at this stage. Its cells are full of granular protoplasm which 
stains darkly with haematoxylin, yellow with iodine, and 
brown with chlor.-zinc-iod. There are no vacuoles and the 
nuclei, which show distinct nucleoli, are near the basal 
cell-walls. 
In an older gland, but before the walls have become at 
all folded, the cells present the appearance shown in Fig. 12. 
They are more elongated perpendicularly to the surface, and 
the protoplasm, still granular, is collected near the free walls, 
carrying with it the nuclei, which are now very conspicuous. 
The basal half of the cell is occupied by a large clear vacuole. 
In the next stage (see Figs, to and 13) some of the cells 
near the centre of the gland-wall have divided tangentially 
by a single transverse septum. Most of the protoplasm 
is cut off in the upper cell. The formation of the transverse 
1 Observations on Pitchered Insectivorous Plants (Part II). Ann. Bot., 
Vol. vii. p. 435. 
