238 
Notes. 
Twin-bundles of the leaf-trace soon uniting after reaching the pith, subdividing 
in the cortex to form eight bundles. 
Centripetal xylem distinct, persisting after fusion of the two leaf-trace strands. 
Tracheides of the inner part of the intermediate secondary wood, as well as those 
of the leaf-traces, spiral or scalariform. 
Medullary rays usually uniseriate, 1-8 cells in height. 
No axillary buds or branches observed. 
Dictyoxylon zone of cortex very broad, fibres not much thickened. 
Seam-nodule, Shore, Littleborough. 
Only one specimen has been investigated, though others are probably referable 
to the same species. The mean diameter of the stem is about 2-5 cm., that of 
the pith about 8 mm. The great distinctness of the centripetal xylem, the early 
union of the leaf-trace strands at the margin of the pith, and the moderate size of the 
latter accentuate the resemblance to Poroxylon. 
3. Mesoxylon multirame , sp. nov. 
Leaf-bases moderately crowded, as in M. poroxyloides. 
Pith large, discoid, with a persistent outer zone. 
Twin-bundles of leaf-trace approximated on reaching the pith, but remaining 
separate for several internodes; subdividing in the cortex as in other species. 
Centripetal xylem dying out rather rapidly after the leaf-trace reaches the pith. 
Tracheides and medullary rays essentially as in M. poroxyloides. 
An axillary branch present in most of the leaf-axils. Base of branch leafless, 
with a flattened stele, recalling a phylloclade. 
Dictyoxylon zone of cortex broad, fibres strongly thickened. 
Seam-nodule, Shore, Littleborough. 
One specimen only has been investigated. Among the preparations, a series of 
fifteen transverse sections was available, in which the course of the leaf-traces and 
axillary steles could be traced with great precision. 
The phyllotaxis, however, remains a difficulty. The orthostichies are suffi¬ 
ciently numerous to correspond to a^ arrangement, if not to a higher fraction, but 
the actual divergence between two successive leaf-traces seems to be considerably less 
than on any usual phyllotaxis. 
The naked axillary branches are remarkable, and very different from the little 
buds of M. Snicliffii —evidently the two organs had quite distinct functions. 
The stem observed is about 2*5 cm. in diameter, the pith measuring just half 
this—12-5 mm. 
4. M. Lomaxii , sp. nov. 
Leaf-bases scattered. 
Pith large and discoid, with a persistent outer zone. 
Twin-bundles of leaf-trace converging, and fusing immediately on reaching 
the pith. 
Centripetal xylem very distinct and persistent. 
Xylem-strands at the margin of the pith sheathed by radiating parenchyma. 
Scalariform tracheides almost limited to leaf-traces, only appearing at the 
extreme inner edge of the intermediate secondary wood. 
