335 
of Lepidostrobus Brow nil, Schpr . 
wards to the sporophylls. This course of the bundles is 
further illustrated by the longitudinal section (Fig. 2), in which 
they may be seen taking their oblique course upward through 
the clear intervening space from the solid central mass into 
the dark peripheral band of the cortex. Special attention 
should be paid to the oblique bundles at the apical end of the 
section ; here a felt of fine filaments connects the bundles, 
while still in the intervening space, with the neighbouring 
tissues. These filaments have already been figured by R. 
Brown 1 , but they appear to have entirely escaped the notice 
of all recent writers on the subject. It will be one of the 
objects before us to examine the nature and origin of these 
filaments. 
Having now taken a general view of the axis in transverse 
and longitudinal section, we may proceed to the more detailed 
examination of the tissues under higher powers (Fig. 3 A). 
Starting from the centre, the bulky pith (/) (characteristic of 
L. Williamsoni) shows no features calling for remark; its 
large thin-walled cells pass over gradually into the thick- 
walled tracheides of the wood (xy), and remind one of the 
relations of the undeveloped, as distinct from the fully matured 
xylem of some concentric bundle. The figure shows well 
how irregular is the outer limit of the woody mass, the sum- 
mits of the crenulations of the peripheral part being occupied 
by smaller tracheides, presumably including the protoxylem. 
The middle of the part shown in the figure is occupied by 
one of those projecting teeth, from which a leaf-trace is just 
about to be given off. The tissues outside the wood are in a 
remarkably fine state of preservation, considering how delicate 
they must have been : a point to note especially is the 
presence of a layer, which I believe to be an endodermis (sh) ; 
it is recognized by the more sharp definition of its walls, 
while in parts the radial walls still appear to show the charac- 
teristic dot. Again, on following the sheath in its sinuous 
course round the central vascular mass, the radial walls of 
the sheath are found ruptured, in exactly the way so often to 
1 Linn. Trans. XX, PI. XXIV, Fig. A. 
