HALLE, FRUCTIFICATIONS OF CLADOPHLEBIS DENTICULATA. 5 
like lines. seen on the upper surface of the carbonaceous layer 
agree with those of the Stockholm specimen. 
In places where the coal has been removed both spe- 
cimens show fairly clearly the arrangement and structure of the 
sporangia. The following description is based mainly on the 
Stockholm specimen, which was the first to be examined. When 
in a dry state, the specimens show only indistinct traces of the 
fructifications; but when the surface is moistened the sporangia 
appear in sharp outlines, their yellowish to dark brown colour 
contrasting vividly with the lighter tint of the rock. The best 
result was obtained with Cedar-oil of the concentration used for 
anatomical preparations. Thisisa method which I have tried on 
numerous different objects and found to be of very great use, 
as the oil causes the different shades of brown and yellow to 
show out most distinctly and thereby reveals details of structure 
which could not be seen before. Cedar-oil has also the great ad- 
vantage that it does not soften or in any way damage the speci- 
mens, as does water. The magnified photographs in pls. 1 and 2 
have been taken by means of the binocular microscope of ZEISS, 
which is indispensable in studies of this kind. 
Corresponding to the vein-like lines on the upper surface 
of the carbonized pinnules, there are seen on the impression of 
the lower side very distinct grooves running from the midrib to 
the margin (pl. 1, figs 1, 2; pl. 2, figs 1, 2). As has been remarked 
above, these grooves represent no doubt the lateral veins. 
'The sporangia are preserved as impressions on which, however, 
the sporangial wall has stuck like a yellow-brown coating. They 
are attached to the surface of the lateral veins along the whole or 
nearly the whole of their length, from the midrib to the margin. 
Thus, they appear on the impression in two rows, one on each 
side of the vein (pl. 1, figs 3—6; pl. 2, figs 3, 4). 
The sporangia are very densely crowded, partly concealing 
each other on the impression. Their length is 0.45—0.50 mm., 
and the apices of the sporangia of each two adjacent veins touch 
each other in the middle of the intervening segment. Conse- 
quently the whole lower surface of the pinnules is covered by 
sporangia. A restored figure showing the disposition of the 
sporangia is given in text-fig. 1. 
The sporangia are sometimes seen to be provided with a 
short stalk, which in one case (pl. 2, fig. 5) has a length of 
/, of that of the capsule, is fairly thick and appears to con- 
