435 
Insectivorous Plants ( Part II). 
Development of the glands. The development of the glands 
on the detentive surface has been already studied by Wunsch- 
mann 1 , and with slight additions the description can apply 
to all except the large marginal glands. The development of 
those lid-glands the surface of which is flat or nearly so, and 
which are slightly sunk in pocket-fossae, agrees exactly with 
that given by him. 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. 
Each marginal gland is first indicated by the simultaneous 
depression of the marginal epidermis and out-bulging of cells 
at the bottom of the depression in obovate outline. As in all 
the other glands, division of the epidermal cells into three layers 
— an outer one of columnar elements and two subjacent ones of 
polygonal elements — occurs, while, so far as I can trace, a few are 
cut off from the innermost of the three to form the rudiment 
of the pulp-cells of the gland. This condition is represented 
in PI. XXI, Fig. 30, and is permanently retained in the first 
six to eight seedling leaves. Comparison of Fig. 30 with 
Fig. 29, taken from the seventh leaf-pitcher of a seedling, shows 
that in both each gland is obovate in outline and protrudes 
slightly from the depression. But in the former, by continued 
outgrowth of the walls of the depression and sinking of the 
gland into the cavity, it eventually occupies the deep and 
hidden position which caused them to be overlooked by most 
observers. 
Professor Dickson referred to the usual presence in large 
marginal glands like those of N. khasyana and N. Phyllam - 
phora , of a central cavity traversing the length of each, into 
which elongated cells of the gland projected. These appeared 
1 Op. cit. pp. 17, is. 
