It is worthy of notice that the radial section of _Spencerites_ (fig. 192) presents a fairly close resemblance to a corresponding section through a cone-scale of _Agathis_ (Kauri Pine)[447]. In each case the megasporangium is attached by a narrow pedicel to the sporophyll and the latter has a similar form in the two plants, though the extent of the resemblance is somewhat lessened by Lang’s more complete account of the Palaeozoic type. If the _Spencerites_ sporangia possessed an integument the similarity with the _Agathis_ ovule would of course be much closer: recent palaeobotanical investigations have shown that ovules and sporangia are not separated by impassable barriers. [Since this Chapter was set up in type a paper has appeared by Dr Bruno Kubart on a new species of _Spencerites_ spore, _S. membranaceus_, from the Ostrau-Karwiner Coal-basin (Austria). The spores are larger than those of _S. insignis_ and in some the cells of a prothallus are preserved. Kubart figures a section of a spore containing a group of seven cells, a central cell, which he regards as an antheridial mother-cell, surrounded by six wall-cells. Kubart (90).] CHAPTER XVI. =Sigillaria.= i. _General._ In view of the close resemblance between _Lepidodendron_ and _Sigillaria_, another lycopodiaceous plant characteristic of Carboniferous and Permian floras, a comparatively brief description of the latter genus must suffice, more particularly as _Lepidodendron_ has received rather an undue share of attention. _Sigillaria_, though abundantly represented among the relics of Palaeozoic floras, especially those preserved in the Coal-Measures, is rare in a petrified state, and our knowledge of its anatomy is far from complete. In external form as in internal structure the difference between the two genera are not such as enable us to draw in all cases a clearly defined line of separation.