240 
ON THE EOSSIL PLANTS OF THE COAL-MEASURES. 
Amongst the numerous other interesting plants for which I am indebted to G. Grieve, 
Esq., of Burntisland, in Fifeshire, is a well-marked Diploxylon closely allied to I). cyca- 
deoideum. Like the rest of Mr. Grieve’s specimens, it is from the deposit of lower carhop 
niferous age which occurs imbedded amongst trappean rocks at Pettycur Bay. This 
specimen is an instructive one, since, though abundantly furnished with primary and 
secondary medullary rays, or rather with the spaces which they occupied, all the cellular 
tissues have disappeared from both, whilst the vascular foliar bundles are well preserved. 
We are thus enabled to distinguish the respective areas occupied by the two tissues 
in a manner that I have not succeeded in doing so distinctly in the other specimens 
described. Each bundle is cylindrical, occupying the centre of the lenticular section of 
the ray when cut at right angles to its direction, and consisting of very small barred 
vessels. Above and below the vessels are open spaces, but which were originally 
occupied by the cellular tissues of the ray, the forms of the cells being strongly im- 
pressed upon the indented walls of the contiguous longitudinal vessels of the ligneous 
zone. I have not discovered in this plant the cellular layer intervening between the 
medullary vascular cylinder and the woody zone ; in this respect it appears to approach 
nearer to the D. vasculare than to the other forms. The vascular medullary cylinder or 
sheath is strongly marked ; but all the medullary cellular tissues have disappeared. I 
pointed out some time ago* that some of these Lepidodendra exhibited a feature not 
previously noticed ; viz. the vessels were not only barred transversely, but, in addition, 
the transverse bars of lignine were connected by a delicate series of threads of the same 
material, running parallel with the longer axis of the vessel. I find this feature in all 
the Diploxylons ; but in the Burntisland specimen it is so faint that it can only be dis- 
covered under the microscope by a careful adjustment of the light. The coarser trans- 
verse bars are also much more irregular in size, number, and direction than is usual 
amongst the Diploxylons of the Upper Coal-measures. 
The Dijjloxylon of Corda is so obviously identical, generically, with the Anabathra 
of Witham, that the latter name ought to be adopted in preference to the former one. 
But ere long, in all probability, both these names will have to be abandoned, since 
there appears to be little doubt that they represent the woody axes of some of the com- 
mon Lepidodendroid plants of the Coal-measures ; and as soon as the identification of 
these internal axes with their correlate external forms is indisputably accomplished, the 
yet older names of the latter must become the adopted ones. Under these circumstances 
it is scarcely desirable to disturb a widely accepted nomenclature, since any day may 
furnish the required connecting link. 
The general conclusion towards which all these additional observations point is the 
same as that of the preceding memoir, which they strengthen and confirm, viz. that all 
these varied plants are constructed upon a common type, and belong to one Lycopo- 
diaceous family. 
* Monthly Microscopical Journal, August 1, 1869, pi. xx. fig. 10. 
Givens College , Manchester , August 30, 1871. 
