This generic name has been instituted by Zeiller[224] for specimens from the coal basis of Blanzy (France). It is applied to heterosporous species with the habit of _Selaginella_: Zeiller preferred the designation _Selaginellites_ to _Selaginella_ on the ground that the type species differs from recent forms in having more than four megaspores in each megasporangium. It is, however, convenient to extend the term to all heterosporous fossil species irrespective of the spore-output. _Selaginellites Suissei_ Zeiller. This species was described in Zeiller’s preliminary note[225] as _Lycopodites Suissei_, but he afterwards transferred it to the genus _Selaginellites_. In habit the plant bears a close resemblance to _Lycopodites macrophyllus_ of Goldenberg; the shoots, 1–3 mm. thick, are branched in a more or less dichotomous fashion and bear tetrastichous leaves. The larger leaves reach a length of 4–6 mm. and a breadth of 2–3 mm.; the smaller leaves are described as almost invisible, closely applied to the axis, oval-lanceolate and 1–2 mm. long with a breadth of 0·5–0·75 mm. Long and narrow strobili (15 cm. by 8–10 mm.) terminate the fertile branches; these bear crowded sporophylls with a triangular lamina and finely denticulate margin. Oval sporangia were found on the lower sporophylls containing 16–24 spherical megaspores 0·6–0·65 mm. in diameter. The outer membrane of the spore is characterised by fine anastomosing ridges and thin plates radiating from the apex and forming an equatorial collarette. The microspores have a diameter of 40–60μ and the same type of outer membrane as in the megaspores. The megaspores of the recent species _Selaginella caulescens_, as figured by Bennie and Kidston[226], resemble those of the Palaeozoic type in the presence of an equatorial flange. It is interesting to find that, in spite of the occurrence of 16–24 megaspores in a single sporangium the size of the fossil spores exceeds that of the recent species. _Selaginellites primaevus_ (Gold.). Fig. 135, A, fig. 138. 1855 _Lycopodites primaevus_, Goldenberg[227]. 1870 _Lycopodium primaevum_, Schimper[228]. 1907 _Selaginellites primaevus_, Halle[229]. [Illustration: FIG. 138. _Selaginellites primaevus_ (Gold.). (After Goldenberg.)] In habit this species, first recorded by Goldenberg from the Coal-Measures of Saarbrücken, is similar to _S. Suissei_ Zeill.