OF THE FOSSIL PLANTS OF THE COAL-MEASUKES. 
213 
the sloping surfaces running from the inferior margin of one cicatrix to the base of the 
upper prominent edge of the next below it. The inner surface of the section exhibits 
the prosenchymatous layer (i), which occupies about one half of the section ; part of this 
prosenchyma consists of cells of the usual fusiform type, whilst other portions are pro- 
longed into tubes, as amongst the Lepidodendra. I found the above specimen amongst 
the Lower Coal-measures near Oldham. 
Though there is no question that the specimen last described is a true Sigillaria , it 
belongs to a type intermediate between the true Favularice and the Syringodendra. 
But Plate XXIX. fig. 39 represents three of the longitudinal ribs of a true Syringoden- 
droid Sigillaria , from a specimen for which I am indebted to Mr. Nield, of Oldham. 
The figure is of the natural size. A transverse section of a portion of this specimen, also 
of the natural size, is seen in fig. 40. Plate XXX. fig. 41 represents a segment of fig. 40, 
magnified 15 diameters, and Plate XXIX. fig. 42, which is also enlarged 15 diameters, 
is a radial longitudinal section which passes through part of one of the leaf-scars. 
I cannot identify this Sigillaria with any of Brongxiart’s species ; but it unmistakably 
belongs to the group of S. Saullii , Schlotheimii, and scutellata , and of which his Syrin- 
godendron cyclostigma has merely been a narrow-leaved example. 
The transverse section (fig. 41) merely exhibits an external layer of parenchyma (Z) 
with an inner one arranged in regular radii, and which consists of an elongated tubular 
form of prosenchyma (i), an arrangement almost identical with that of the corresponding 
section of Famdaria (Plate XXVIII. fig. 30). The longitudinal section (Plate XXIX. 
fig. 42) is much more interesting: at l we again have the parenchyma, the cells of 
which tend to an arrangement in lines which incline upwards and outwards. Immedi- 
ately below each leaf-scar the cells are purely parenchymatous, but lower down, in the 
space between two leaf-scars, they become more elongated and fusiform than in the 
portion figured. 
The elongated prosenchyma (i) of the inner epiderm and outer bark is very regularly 
arranged in elongated tubuli ; but as the very thin radiating laminae of these elongated 
cells do not exactly run parallel with the plane of the section, they are intersected at 
intervals by lines, k', giving rise to the appearance of medullary rays, an appearance 
also represented in the corresponding portion of Broxgxiart’s Sigillaria elegans. That 
author describes this tissue as “ forme de cellules allongees, tres-serrees terminees par 
des extremites coupees obliquement, et dont yrtusieurs contigues correspondent a la memo 
hauteur , de maniere que lews terminal sons forment des lignes transversales en zigzag”*. 
The last portion of the sentence which I have italicised is, I believe, a mistake. I have 
no question that, in my specimen at least, the appearance is due to the cause just speci- 
fied, viz. to a want of exact parallelism between the planes of the radiating laminae of 
prosenchyma (seen in the transverse section, fig. 41, Jc) and that of the vertical section. 
Of course whenever the latter passed obliquely through one of the former, which it does 
continually, it would cut off a number of tubes in the same line, and give them the 
* Loc. cit. p. 419. 
2 F 
MDCCCLXXII. 
