OF THE FOSSIL PLANTS OF THE COAL-MEASURES. 
507 
endophloeum, d, is still more strongly marked than in the former specimen. I cannot 
doubt for a moment the specific identity of figs. 20 and 22. The presence of the 
tylose, therefore, would seem to be an accidental phenomenon, and not a specific 
feature of the former specimen. As for the dark line, li, I think I cannot be wrong in 
regarding it as identical with a similar boundary-line or bundle-sheath seen in many 
recent ferns, and which occurs in a form closely resembling that of fig. 20 in the 
petioles of Woodwardia orientalis. So far as its central vascular bundle is concerned, 
this plant somewhat resembles the Zygopteris elliptica of M. Renault but it differs 
in the relative proportions of its transverse terminal arcs, which are very much longer 
and less robust in E. elliptica than in my species. The various cellular layers, b, c, d, 
and g, of the latter not being preserved in M. Renault’s specimen, makes a more 
detailed comparison of the two plants impossible. I propose to distinguish my plant 
by the name of Rachiopteris insignis. 
Fig. 23 represents a lateral bundle passing outwards through the cellular layer, 
b, of fig. 21. In its centre we obviously have the central bar, e, of fig. 20 ; but it 
is impossible to say which of the surrounding structures are vascular and which 
cellular, or to determine whether this is the bundle of a secondary petiole, or of a 
root, but it is most probably the former. 
Conceptacles. 
In my last memoir I described some remarkable reproductive structures under the 
generic names of Sporocarpon and Oidospora. Having obtained additional examples 
of these objects, I am now able to throw further light upon them, and also to add to 
then- number. I described one of these under the name of Sporocarpon elegans (loc. 
cit., p. 348, Plate 23, figs. 67, 68, 69, 69a), and a second I designated S. compactum 
(loc. cit., p. 349, Plate 24, fig. 7 6a). Specimens recently discovered suggest the possibility 
that these apparently distinct species may be but different stages in the development 
of the same organism ; the latter being the younger, and the former the more matured 
states. It is also possible that the minute objects which I designated Oiclosporce, 
may be very young forms of the same, though at present I have not sufficient evidence 
to prove that such is the case. 
Fig. 24 is a transverse section through the centre of a very perfect specimen of the 
Sporocarpon elegans. Its radially disposed, hour-glass-shaped cells, a, are arranged in 
the most symmetrical manner. Some of the cells are prolonged into long, radiating, 
unicellular hairs, b, b, whilst in others, c, c, these hairs have been broken off near the 
periphery of the organism. This example has further satisfied me that in the specimens 
ordinarily met with, most of these hour-glass cells are open at their peripheral extre¬ 
mities, and that all of them were once more or less prolonged into hollow hairs, the 
free portions of which have in most instances been broken off I have already referred 
to the brittleness of many of these cellulose hairs, as illustrated by those clothing the 
* ‘ Annales des Sciences Natnrelles,’ 5 e serie, Bot., tom. 12, plate 7, fig. 10. 
