116 
CASH ASD HICK I ON FOSSIL FUNGI. 
specimens are exhibited in three microscopic slides, showing 
sections of carboniferous plants, cut and prepared from the 
" nodules " or " coal-balls " described in our former paper. 
On the first slide we have a transverse section of the 
petiole of a fern, as well as a section, also transverse, of a 
portion of what appears to be a branchlet or rootlet of some 
other plant, but which from its fragmentary character has 
not yet been determined. The fungus is confined to the 
latter part of the preparation, but it may not be amiss to note 
in passing that the fern is evidently Zygopteris Lacattii of 
Renault, or, as Professor Williamson prefers to term it, 
Rachiopteris Lacattii. A single fibro- vascular bundle, com- 
posed of xylem and phloem elements, occupies the centre of 
the petiole, while the remainder is made up of fundamental or 
ground tissue, apparently similar to that of living ferns. The 
phloem was originally surrounded by the xylem completely, 
as is usually the case in the bundles of vascular cryptogams, 
but having to a large extent disappeared, its place is occupied 
by mineral matter. At two opposite points of the bundle 
the phloem projects into the xylem for a little way, and then, 
branching right and left, forms a Y~ sna P e( l mass, with very 
divergent arms. In one of these inwardly projecting masses 
of phloem, the histological elements of which are remarkably 
well preserved, there are several larger cells, the arrange- 
ment, position, and appearance of which strongly suggest 
their homology with sieve-tubes. It is, however, to the 
partial disappearance of the soft and delicate phloem tissue 
that we wish especially to draw attention ; for in this fact 
we seem to have an indication that the fern lay exposed to 
atmospheric and other adverse influences for some time, and 
that death and decay had already commenced before it was 
covered up and the process of fossilisation had set in. Ex- 
tending this inference to the accompanying tissue in which 
the fungus is found, and we may form some idea of the 
