go BRUCE—STRUCTURE AND FUNCTION 
in the absence of a vascular strand traversing its centre. It 
has three layers (Fig. 24) of which the outermost consists of 
about twenty parallel cell-rows. The cells of these rows are 
elongated in the long direction of the pedicel, being about two 
to three times as long as they are broad. They have thin outer 
walls and thin radial walls, and are firmly united together 
laterally. The second or intermediate layer consists of from six 
to eight parallel cell-rows, and surrounds the third or innermost 
layer, which usually consists of one cell-row occupying the centre 
of the pedicel. 
THE GLANDULAR HEAD.—This is seated on the end of 
the pedicel and appears as an ovoid swelling, circular on trans- 
verse section (Fig. 26). In structure it resembles the pedicel. 
In the centre is a single cell-row, not digestive, a continuation of 
the central row of the pedicel. The intermediate layer forms a 
dome-shaped cover over the central row (Fig. 25). The cells 
of the outermost layers are g/and-cells, and are a continuation of 
the outermost layer of the pedicel. If any one row of cells is 
traced from the pedicel into the glandular head its cells, which 
are elongated in the stalk, will become shorter, then square, and 
finally flattened. 
The gland-cells themselves are united to those of the inter- 
mediate row by their inner surfaces, but there is no connection 
between adjacent gland-cells, that is to say, the lateral walls of 
the gland-cells do not touch, and each gland-cell is therefore free 
along its sides (Figs. 25, 26). 
As in Drosera and Drosophyllum there are no pores on the 
gland-cells for the extrusion of secretion. 
The smaller tentacles differ from the larger ones only in 
simplification of the construction. A section through the head 
of one of the smaller tentacles (Fig. 27) shows only a single 
central cell-row to which the gland-cells are attached and the 
intermediate cell-layer is wanting (Fig. 28). In a still similar 
tentacle (Fig. 29) the head is composed of the layer of gland- 
cells alone, and even here the gland-cells are not united to each 
other laterally (Fig. 30). In the simplest form of all, the 
tentacle consists of one cell-row, the lower cells of which are 
elongated and form the pedicel, while the upper cells are 
flattened and form the glandular head. 
