538 MR ROBERT KIDSTON ON 
Professor Weiss also makes reference. My thanks are also due to Professor Bowsr 
for the loan of another transverse section from the same block, which he received from 
the late Professor WILLIAMSON. 
The remaining portion of the block from which these slides were made (No. 1949a) 
is about 14 inches long, and shows a subepidermal surface with a single tubercle. The 
leaf cushions have been removed, so it thus possesses no external characters for a generic 
determination. 
Part of a section made from this specimen is figured by WILLIAMSON in his Memoir 
XIX., on pl. iv. fig. 30.* 
When one examines the remains of the original specimen and the slides made from 
it, itis dificult to interpret the relation of the parts to each other. One difficulty in ex- 
plaining the relationship of the parts is, that if the two sides of the specimen represent the 
subepidermal surfaces of the original stem, how does the portion figured by WILLIAMSON 
come to hold the position that it does? Again, the pressure to which the specimen, 
and especially the vascular axis, has been subjected, makes a critical examination of its 
structure very difficult. These circumstances have prevented me from arriving at any 
conclusion as to the true position of this fossil.t 
My thanks are due to Dr A. Smrrx Woopwapp, F.R.S., Keeper of the Geological 
Department of the British Museum, for kindly giving me the opportunity of examining 
the specimens in the ‘“‘ Williamson Collection,” and to Dr Hoye for sending me the one 
contained in the Collection of the Manchester Museum. 
VI. That the vascular axis of the specimen described by Professor Wess belongs 
to the same type of structure as the vascular axis of Lepzdophlows fuliginosus is 
beyond dispute. The stems of these two plants are closely related in anatomical 
structure, but I do not think they are identical. Professor Weiss in his paper — 
points out some slight differences, but what I regard as three important differences 
seem to be passed over in his description as of too little value for a separation of 
the two plants. The first is the very prominent and continuous (except where 
broken by the presence of leaf traces) band of tissue described by him as phloem. 
‘This layer is very much more developed in the specimen under discussion than in 
typical Lepidophloios fuliginosus. The second distinguishing point is the greater 
number of leaf traces given off by the vascular cylinder of Professor WHiss’ 
specimen, while the third distinctive character is the presence of a well - defined 
pericycle. 
The leaf traces are generally composed of a larger number of elements than 
those of Lepidophloios fuliginosus, and therefore appear more prominent, and are 
frequentiy larger in transverse section. From these causes, and the fact of the 
leaf traces being more numerous, they form a much more distinct ring of leaf traces 
surrounding the axis than do those of what I regard as the true Lepidophloios 
* Phil. Trams. vol. clxxxiv. p. 20, 1893. 
+ Another portion of this specimen (Williamson, 19494) is in the Wild Collection, Manchester Museum. 
