compared with other genera of Cycadeae . 6 1 3 
between the vascular zones and the leaves a direct system of 
communication. 
The direct connexion existing between the several rings of 
vascular tissue, apart from that afforded by the leaf-traces, 
was very clearly seen by the aid of radial sections which 
exhibited at intervals, especially between the normal and the 
first anomalous rings, very broad bands of wood and bast 
connecting the two both in a downward (the more marked of 
the two) and in an upward direction. Connexions in both 
directions may sometimes occur in close proximity, which 
thus give the curious looped appearance shown in Fig. 11, which 
is a diagrammatic, though accurate, representation of the 
structure. In this manner, by the continuity of the cambium 
of the different zones, a perfect communication is established 
between the various parts of the conducting-tissue of the stem. 
It should be mentioned that the curious ‘ transfusion- 
tracheides,’ which have already been several times referred to, 
constantly occur in considerable numbers (as is also the case 
in Cycas media) on the inner margin of the anomalous rings. 
They are of very various shapes, being either quite isodia- 
metric, or oblong, contorted and shapeless, or more elongated 
and narrower, and having for the most part bordered pits on 
their walls. Whether they always formed a continuous series 
or not, as in normal transfusion-tissue, it was difficult to 
determine, and I did not succeed in so doing, but such is 
probably the case (Fig. 12/). 
A tangential section through the wood or the bast exhibits 
the curious looped structure caused by the bending of the 
tracheides and fibres in the tangential direction, this being 
due to the growth and expansion of the medullary rays which 
traverse these gaps. In each such loop or gap is seen a leaf- 
trace bundle with xylem directed upwards and one or two 
mucilage-canals (Fig. 13). 
Structure of the Cortex. 
The cortex occupies an area of the stem almost equal in 
thickness to that of the vascular zone. It is chiefly characterized 
