Groom . — On Dischidia rafflesiana ( Wall ’.). 239 
Each of the small cells (Figs. 2, 3, 4, 5, 6, 7, 8) is roughly 
conical in shape, with a base arched outwards and a truncate 
apex inwards. Its cell-wall is completely cuticularized and 
lignified. In a tolerably young stage the outer wall shows 
the following structure : the lamellae of the epidermal cell 
(still consisting of cellulose) are succeeded internally by a thick, 
cuticularized and lignified membrane which is traversed by 
radial lines (Fig. 5). A surface view shows that, corresponding 
to these fine lines, there are round dots : so that this view of 
the outer wall reminds one of a sieve-plate with minute pits 
(Fig. 6). Hence the wall is traversed either by fine canaliculi, 
or by rods of substance different to that constituting the rest 
of the wall. I was unable to decide which of these two 
suggestions is correct. In addition there is very often a large 
pit in this outer wall (Fig. 7). The question arises as to the 
function of these conical cells. In shape, arrangement, and 
abundant protoplasmic contents, they correspond to the 
passage-cells found in epidermoidal layers. But, in place 
of having thin cellulose-walls, they have very thick heavily 
suberized outer walls. However, for the following reasons, 
it is probable that water can pass through these walls. First, 
there is often a large pit in the external wall. Secondly, the 
radial, striation of this wall is especially marked in younger 
cells, i.e. in cells which occupy regions still capable of absorb- 
ing liquids ; whilst in older parts which have ceased to absorb, 
the striation is often replaced by a granulated appearance. 
Thirdly, at the region of contact with the supporting bark 
the epidermoidal cells are smaller than elsewhere, but the 
diminution of size takes place particularly in the elongated 
cells: hence in this region the surface of the conical cells is 
relatively increased, and this is precisely the spot at which 
absorption of liquids is most active. So there is ample reason 
to conclude that the conical cells are peculiar passage-cells, 
and probably that the striae in their external walls denote 
channels for the conduction of liquids. In some of these 
conical cells various bodies occurred, in the shape of spore- 
like granules, bacteroid-like bodies, and large stratified masses 
