282 
HICK : CALAMOSTACnYS BINNKYANA. 
of tlie specimen described in Part V. is " probably cellular, not vas- 
cular, as described in the Memoir." Other undescribed specimens 
are also referred to as showing a '•central medulla" which is 
" distinctly cellular." 
As regards the vascular bundles which in some cases surround 
the center of the axis, nothing is said by Carruthers and Binney, 
and onr present knowledge of them is entirely due to Williamson. 
Unfortunately, however, Williamson's description of them was 
dominated by the idea that they enclosed a strand of vascular 
tissue, and this led him to compare them with the secondary vascular 
bundles of the plant he then termed Asterophyllites" 
From all this it is clear that much confusion exists respecting 
the histological composition of the axis of Calamostachys Binneyana, 
and until it is cleared up no serious attempt can be made to remove 
the equally prevailing confusion which obscures its affinities and 
systematic position. 
Turning now to the new material, it may be well to state at the 
outset that after a careful and prolonged study of it, I have come 
to the conclusion that Calamostachys Binney ana is not only charac- 
terised by a parenchymatous pith in the center of the axis, but also 
by a ring of primary vascular bundles round that pith, which have 
the characteristics of those of Cahmites. 
Among the transverse sections are several which have been well 
preserved, and are more than usually perfect so far as concerns the 
axis at least. In these the parenchymatous character of the central 
tissue is indicated not only by the appearance and arrangement of 
the elements, their irregularities of size and shape, and the presence 
of intercellular spaces, but also by the fact that neither the side 
walls where inclined to the vertical, nor the transverse walls where 
visible, show any traces of scalariform or other vascular markings. 
For demonstrative evidence, however, we must go to the longitudinal 
sections, one of which is represented in figs. 2, PL I., and 3, PI. II. This 
is a magnificent specimen whose axis is practically perfect, and both in 
this and other respects seems much superior to those previously pub- 
lished. Both extremities appear to be wanting, but the part pre- 
* Now known to be SphenophyUum. 
