2. _Favularia Type._--This has been well described by Brongniart and by Renault,[CV] and differs from the above chiefly in the fact that the outer exogenous woody zone is composed of reticulated instead of scalariform tissue, and the inner zone is of the peculiar form which I have characterised as pseudo-scalariform. [CV] "Botanique Fossile," Paris, 1881. 3. _Sigillaria Proper._--This I have illustrated in my paper in the "Journal of the Geological Society" for May, 1871, and it appears to represent the highest and most perfect type of the larger ribbed _Sigillaria_. This structure I have described as follows, basing my description on a very fine axis found in an erect stem, and on the fragments of the woody axis found in the bases of other erect stems: _a._ A dense cellular outer bark, usually in the state of compact coal--but when its structure is preserved, showing a tissue of thickened parenchymatous cells. _b._ A very thick inner bark, which has usually in great part perished, or been converted into coal, but which, in old trunks, contained a large quantity of prosenchymatous tissue, very tough and of great durability. This "bast-tissue" is comparable with that of the inner bark of modern conifers, and constitutes much of the mineral charcoal of the coal-seams. _c._ An outer ligneous cylinder, composed of wood-cells, either with a single row of large bordered pores,[CW] in the manner of pines and cycads, or with two, three, or four rows of such pores sometimes inscribed in hexagonal areoles in the manner of Dadoxylon. This woody cylinder is traversed by medullary rays, which are short, and composed of few rows of cells superimposed. It is also traversed by oblique radiating bundles of pseudo-scalariform tissue proceeding to the leaves. In some _Sigillariæ_ this outer cylinder was itself in part composed of pseudo-scalariform tissue, as in Brongniart's specimen of _S. elegans_; and in others its place may have been taken by multiporous tissue, as in a case above referred to; but I have no reason to believe that either of these variations occurred in the typical ribbed species now in question. The woody fibres of the outer cylinder may be distinguished most readily from those of conifers, as already mentioned, by the thinness of their walls, and the more irregular distribution of the pores. Additional characters are furnished by the medullary rays and the radiating bundles of scalariform tissue when these can be observed. [CW] These are the same with the wood-cells elsewhere called discigerous tissue, and to which I have applied the terms uniporous and multiporous. The markings on the walls are caused by an unlined portion of the cell-wall placed in a disk or depression, and this often surrounded by an hexagonal rim of thickened wall; but in all cases these structures are less pronounced than in _Dadoxylon_, and less regular in the walls of the same cell, as well as in different layers of the tissues of the axis.