220 DR. D. H. SCOTT : 
by Dr. Zalessky (1911, Pl. 3. figs. 3-62). This author associates the species 
with C. fascieularis in his genus Eristophyton. Two specimens have come 
under observation, Solms- Laubach's stem from Silesia and the British one 
collected by Dr. Kidston at Norham Bridge on the Tweed. For the purposes 
of the present paper I have also examined sections, kindly lent to me by 
Dr. Kidston and Dr. Gordon, of a specimen received by the former from 
Mr. Dunlop, and also derived from the Norham Bridge locality. This 
fragment agrees so closely in dimensions, appearance, and state of preser- 
vation with the original Tweed specimen, that I think it must bea part of 
the same stem. The new sections have afforded some fresh data for the 
study of the leaf-traces. 
Except for a fragment of bark, the specimens investigated include only the 
pith and wood. The characters of the species are briefly as follows :— 
The pith is large, 13-15 mm. in diameter in the British specimens and 
about 8 mm. in that from Falkenberg. A striking feature of the pith is the 
presence of sclerotic nests, with radiating cell-rows around them (Phot. 27), 
recalling the similar structures in Lyginopteris. This character is entirely 
absent in C. fascicularis and in all the other species referred to the genus. 
There are no medullary tracheides. Around the pith and in contact with the 
secondary wood, numerous primary xylem-strands, sometimes confluent with 
one another, are disposed. These strands show the same variation in size as 
those of C. fascicularis, the maximum diameter being attained as the strand 
begins to pass out into the secondary wood. The xylem-strands, owing to the 
large size of the pith, appear less important than in the preceding species, but 
their absolute dimensions are not much less, the outgoing strands reaching 
a diameter of 0'8 mm. In this part of their course they are centrally 
mesarch ; lower down, as the strand diminishes in size, the centripetal portion 
becomes reduced, and an endarch structure is assumed. Strands in three 
different phases are shown, from the Falkenberg specimen, in Phots. 24-26. 
The first is a large strand just entering the wood, with centrally mesarch 
structure *. Phot. 25 shows a bundle lower down in its course, reduced in 
size, but still mesarch, while in Phot. 26 we see a strand at a still lower level, 
very small, and distinctly endarch in structure. These changes are quite 
parallel to those in the xylem-strands of C. fascicularis, but in C. Beinertiana 
they go further, the centripetal xylem dying out altogether. 
. The new sections of the British specimen show the leaf-traces at various 
points in their passage through the secondary wood. "l'hree such traces may 
appear in the same transverse section (Phot. 27), so the internodes must 
have been short, for the trace, after leaving the pith, curves rapidly outwards, 
so as to be cut very obliquely in transverse sections of the wood. I have not 
* There is a group of small elements suggesting a second protoxylem in an exarch 
position. I have not seen this elsewhere and cannot offer any explanation. This strand 
and the endarch one have already been figured by Zalessky (1911, Pl. 3. Phots. 4, 5, 6, 6a). 
