determine the symmetry: as fig. 506, A, shows, casts indistinguishable from some examples of _Platyspermum_ are radially symmetrical. Brongniart[958] extended the original definition of _Rhabdocarpus_ to include certain anatomical characters, and these have been more fully defined by Bertrand[959]. It is for seeds showing these anatomical features that the name _Rhabdospermum_ is now proposed. This course is followed on the ground that it is advisable to avoid confusion between petrified specimens and impressions which in spite of superficial resemblance may not be closely related. In some cases it is practically certain that an impression of the _Rhabdocarpus_ type is generically identical with a seed of similar form showing the anatomical structure of _Rhabdospermum_, but unless identity is established a distinct terminology is preferable. The use of the generic name _Rhabdospermum_ carries with it an implication of platyspermy, but under _Rhabdocarpus_ may be included seeds which are radiospermic and platyspermic. Some seeds agreeing with _Rhabdospermum_ are referred by Grand’Eury[960] to _Poroxylon_, and it is probable that _Rhabdospermum_ like _Cardiocarpus_ is a Cordaitean seed. On the other hand _Rhabdocarpus_ may well include species, apart from those transferred to _Neurospermum_, that belong to Pteridosperms. A species, _Rhabdocarpus Oliveri_, recently described by Kidston[961] from the Staffordshire coalfield is an example of a radiospermic seed which may be assigned to a Pteridosperm. The type-specimen is an ovate seed 4 cm. long and 2 cm. broad agreeing in form and surface-features with _Rhabdocarpus_ as already defined, but the evidence it affords of internal structure is insufficient to determine its position with regard to genera founded on anatomical characters. Other examples of _Rhabdocarpus_ are described by Lesquereux[962] and White[963] from American Coal Measures, by Grand’Eury[964] from the Loire, by Renault[965] from Autun, and by many other authors. =Rhabdospermum.= Gen. nov.