In some specimens of _Pleuromeia_ the upper portion is clothed with crowded and imbricate sporophylls which reach a length of 2·5 cm., a maximum breadth of 2·7 cm., and a thickness of 1 mm. Each sporophyll has a thin wing-like border, and on the lower face are several parallel lines. Solms-Laubach describes the sporangium or ovule as attached to the lower surface of the sporophyll and this opinion has been confirmed by Fitting[163] who has also brought forward satisfactory evidence in favour of the sporangial nature of the reproductive organs. Fitting found numerous spores in the Bunter Sandstone near Halle; these are flattened circular bodies 0·5–0·7 mm. in diameter with a granulated surface and the three converging lines characteristic of spores produced in tetrads. The comparison made by this author between the sporophylls of _Pleuromeia_, which bore the sporangia on the lower surface instead of on the upper as in other lycopodiaceous plants, and the pollen-sacs of Conifers, is worthy of note in reference to the possible relationship between Conifers and Lycopods. A comparison of the _Isoetes_ stem represented in fig. 132, A, with the base of a _Pleuromeia_ shows a striking similarity, but, as Fitting points out, the Stigmaria-like arms of the fossil contained a vascular cylinder whereas the blunt lobes of _Isoetes_ consist exclusively of cortical tissue, the roots being given off from the grooves between the lobes of the tuberous stem. The position of _Pleuromeia_ must for the present be left an open question; it is, however, clear that the plant bears a close resemblance in the form of its base to the Stigmarian branches of _Lepidodendron_ and _Sigillaria_. The vegetative shoot appears to be constructed on a plan similar to that of these two Palaeozoic genera, but the strobilus is of a different type. It would seem probable that _Pleuromeia_ may be closely allied to _Isoetes_ and to the arborescent Lycopods of Palaeozoic floras. It is not improbably a link in a chain of types which includes _Sigillaria_ on the one hand and _Isoetes_ on the other. It is not improbable that a specimen from the Lower Bunter of Commern which Blanckenhorn made the type of a new species, _Sigillaria oculina_ (fig. 134, B) is specifically identical with _Pleuromeia Sternbergi_. An examination of a cast of the type-specimen in the Berlin Bergakademie led me to regard the fossil with some hesitation as a true _Sigillaria_, but a more extended knowledge of _Pleuromeia_ lends support to the view adopted by Potonié[164] that Blanckenhorn’s plant is not genetically distinct from _Pleuromeia Sternbergi_. The resemblance between _Sigillaria oculina_ and some of the Palaeozoic species of _Sigillaria_ emphasised by Weiss[165] has given rise to the belief that the genus _Sigillaria_ persisted into the Triassic era; it is, however, highly probable that the Bunter specimen has no claim to the generic name under which it has hither to been known.