^8S Walton.—On a New Method of investigating Fossil 
The following examples are given of plants which yielded transparent 
transfer preparations: 
IV. Sphenopteris nummular ia, Andr. 
This specimen has exceptionally tough, well-preserved cuticular surfaces. 
The mesophyll has decayed, and no black substances are left. The lamina 
is thus quite transparent (PL IX, Fig. 8). The conducting tissue of the 
rachis and pinnae shows up as dark bands. Other dark lines due to folding 
of the cuticles also occur, and must not be confused with the conducting 
system. In places the scalariform thickening of the walls of the tracheides 
in the rachis can be seen. A few small hairs occur on the under surfaces 
of the pinnae. The outlines of the epidermal cells are clearly defined, and 
in one or two cases stomata (PI. IX, Fig. 9) are visible. The ends of the 
pinnae and pinnules have a markedly revolute margin. Owing to its tough¬ 
ness, the plant figured in PI. IX, Fig. 8, was flattened out in soft balsam 
under a cover-slip. 
V. Oligocarpia gutbieri, Gopp. 
Gresford Colliery, Wrexham. Carboniferous. (Middle Coal Measures.) 
The genus Oligocarpia was instituted for a group of Carboniferous 
ferns, of which the sporangia and the soral arrangement were more or less 
known. I made several transfer preparations of this plant, as a considerable 
quantity of material was available, and many interesting details of structure 
were revealed by them. Sterile and fertile pinnules were observed (PL IX, 
Fig. 10). The lamina in each case was transparent and the venation showed 
up clearly. The rachis was furnished with scattered hairs, consisting of 
a filament of cells tapering off to a fine point. In one portion of the surface 
stomata of the common type could be seen, but it was impossible to tell on 
which surface the individual stomata occurred. The cuticles of the lamina 
are not well preserved. The sori are situated over the lateral veins on the 
fertile pinnules and have two to even sporangia. Some of these sporangia 
(PL IX, Fig. 11) are semi-transparent. The annulus appears to be uni- 
seriate in most of those examined, but it is possible that it might be double 
in a few examples. The sporangia appear to be almost sessile ; the stalks 
must be very short. 
VI. Fungus. Cf. Dematiaceae. Carboniferous. 
In several of the transfer preparations made in the course of these 
investigations, fungal hyphae are found in association with the remains of 
the vascular plants. Sometimes the hyphae are found on the surfaces of the 
plants, at others they are found traversing the matrix between them, 
suggesting that the fungi are found in their place of growth. 
In a few preparations spore-forms have been observed. In one pre- 
