of the Fossil Plants of the genus Sigillaria. 121 
they have an oval form, are an eighth of an inch in length, in the longi- 
tudinal direction of the stem, and are disposed in a spiral order ; they 
are now vacant, but there is little doubt of their having been originally 
filled with prolongations of the delicate cellular tissue which formed the 
inner part of the zone. The leaf cords occupy the inferior part of the 
vascular passages. 
The pith, according to Brongniart, is composed of largish fusiform cells. 
It is unnecessary to discuss in this paper the situation which Lepido- 
dendron holds in the vegetable kingdom: all that is required for our 
present purpose is, to bear in mind the very singular characters of its 
medullary sheath or vascular cylinder, which is rather large, and with- 
out any openings by which the tissue of the pith could communicate 
with that of the double zone. It must also be attended to, that this plant 
possesses no ligneous tissue, arranged in a radial manner, as we have 
seen in Sigillaria elegans. 
Let us, in the next place, consider that remarkable fossil which Mr 
Witham was the first to make known, under the name of Anabathra 
pulcherrima, 
At the time when Anabathra was described, few botanists had attended 
to the minute differences in vegetable tissue, which form so conspicuous 
a feature in the phytological works of the present day: hence a few 
errors have been committed in drawing up the description which has 
been published of this fossil. Some of these errors have been rectified 
by M. Brongniart in his ‘‘ Observations on the Internal Structure of 
Sigillaria elegans ;” but as there are others which this gentleman had not 
the means of correcting, I have been induced to enter into the following 
description more minutely than would have been otherwise necessary. 
It requires also to be stated, that, with the view of enabling me to become 
acquainted with the internal structure of fossil plants in general, Mr 
Witham has, in the most handsome manner, placed in my hands the 
whole of his invaluable collection of sections, among which there is an 
instructive suite of Anabathras. To this gentleman, for so marked an 
act of kindness, there is certainly due from me an expression of very 
deep obligation. 
Before commencing to describe the tissues of Anabathra, it is neces- 
sary to make a slight reference to the state in which Mr Witham’s 
specimen existed, when first discovered. It was invested with an ir- 
regular coat of mineral matter, in which were observed numerous small 
portions of vegetable tissue, intermixed with what appear to be twigs. 
Mr Witham has represented this coat, charged with its vegetable frag- 
ments, in Plate VIII., figure 7, of his ‘‘ Internal Structure of Fossil 
Plants.” The matrix, as it ought rather to be called, was in immediate 
contact with the tissue of what, we shall presently see, is the ligneous 
zone of the fossil, a circumstance which prevents us coming to any con- 
clusion as to the thickness of its bark; for instance, whether it was 
