200 Yapp.— Two Malayan ‘ My rmecophilous ’ Ferns. 
cushion as the parent gallery. The other branch runs forwards 
and slightly inwards, and ends blindly in the leaf-cushion next 
in front, on the other side of the stem. 
Thus each leaf-cushion contains a transversely arranged 
series of three blind galleries, of which the middle and outer 
ones communicate with the ventral gallery at a point imme- 
diately below the cushion itself, while the third, or inner one, 
does so at a point below the leaf-cushion next in order 
behind. These three galleries are seen in Fig. 18, which 
shows a horizontal section through a leaf-cushion, some 
distance below the articulation of the leaf ; while Fig. 1 5 
shows the same in vertical section. There are, at least in 
the case of the larger leaf-cushions, external indications of 
these three diverticula in the form of slight bulgings of the 
cushions. These are shown on several of the leaf-cushions in 
Fig. 19. 
The whole system then consists of a central median ventral 
gallery which gives off, alternately on either side, lateral 
galleries to the branches, and a dorsal series of chambers, 
each branched into three. The branches of these chambers 
are arranged roughly in the form of an h, each limb of which 
finally turns upwards, the two lower ending blindly in one 
leaf-cushion, and the upper in the leaf-cushion next in front 
on the opposite side of the stem. These dorsal chambers 
communicate with the main gallery close to the points of 
origin of the side-galleries. Fig. 20 represents diagram- 
matically a plan of the main gallery and its lateral branches, 
and Fig. 21 a plan of the dorsal chambers. 
The arrangement of galleries in the branches is essentially 
the same as that of the main stem, except that in those cases 
where the lateral branchlets of the branches themselves are 
suppressed, the side galleries are of course not fully developed. 
Fig. 22 represents a nearly median vertical longitudinal sec- 
tion through the rhizome ; it shows the main ventral gallery, 
and also cuts through the two series of forwardly directed 
branches of the dorsal chambers. Fig. 23 is a similar section 
passing through the apices of one of the two longitudinal 
