124 Contributions towards Establishing the General Character 
belong to this part, since it is simply a portion of fusiform tissue crossing 
the centre of one of the transverse sections. 
Reverting to the ligneous tissue, and adverting to the longitudinal sec- 
tion represented in figure 4, plate IV., which is at right angles to the me- 
dullary rays, and through the marginal strip, our attention must now be 
directed to those large openings (e) which form so prominent a feature. 
There are only two represented, owing to a greater number requiring 
more space than could be allowed for the figure: it consequently re- 
quires to be stated that they are arranged in a spiral manner. Mr 
Witham described these openings as containing the medullary rays, 
which is not the case, because what has been probably taken for cellu- 
lar tissue, is, in reality, a bundle of small vessels (/), similar to those 
which occupy the outer part of the medullary sheath. Although the 
longitudinal sections do not exhibit any of these bundles springing from 
the vascular cylinder, their proximity to this part, in some transverse 
sections (see fig. 2), together with the fact just stated, leave no room to 
doubt as to their having constituted the leaf cords of the plant. Ac- 
cording to Mr Morris, it would appear that Dr Brown had ascertained 
this point some time since.* Owing to one of the openings or vascular 
passages having been intersected in a portion of its course through the 
ligneous zone, as shewn in the longitudinal section parallel to the me- 
dullary rays, which is represented in figure 3, Plate IV., we have dis- 
played in a very instructive manner, a leaf cord or vascular bundle (/) 
traversing at right angles the ligneous tissue: a similar bundle is ex- 
hibited in the transverse section, fig. 2. These two sections prove that 
the leaf cords curve but very slightly in their passage through the lig- 
neous zone, as they proceed horizontally for a considerable distance. 
From the passages being in part vacant (vide fig. 4), it may reasonably 
be supposed that the cords were accompanied in their course with a por- 
tion of cellular tissue. 
We may now be permitted to say a few words on the comparative 
anatomy of Anabathra. No one can escape being struck with the simi- 
larity which this plant possesses in some points of its structure to Sigil- 
daria and Lepidodendron. The width of the ligneous zone is certainly 
greater in Anabathra than in Sigillaria, but there scarcely appears to 
be a shade of difference in the character of its constituent tissue in 
either plant; while between Lepidodendron and Anabathra there is in 
their vascular cylinder the closest resemblance. It is, therefore, clear 
that these three plants are nearly related to each other. 
The resemblance between Anabathra and Lepidodendron in their vas- 
cular cylinder, has induced Brongniart to hazard a question to the effect 
~—May the latter not be the young branch, and the former the stem, of 
* Transactions of the Geological Society, 2d series, vol. v., description of 
Plate XXXVIUII. 
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