The larger seed shown in fig. 501, D, from Commentry, described by Renault and Zeiller[1020] as _Cardiocarpus sclerotesta_, is another example of _Cordaicarpus_ as now defined. IV. +Miscellaneous Seeds.+ In this section are included genera based on characters of comparatively little morphological importance; their claim to treatment under a common heading is that we know little or nothing of their anatomical features or of the parent-plants. i. _Ribbed seeds._ The seeds represented by the following genera possess ribs or flanges usually in multiples of three; the transverse section may be triangular, hexagonal, or polygonal. The symmetry is generally radial, but it is difficult to determine whether a slight departure from the radiospermic form is an original feature or the result of pressure. Some of the ribbed seeds with which we are now concerned are no doubt closely allied to _Trigonocarpus_ and should be included in the Trigonocarpales, but others may well be distinct forms. Genera: _Hexagonocarpus_, _Decagonocarpus_, _Polypterocarpus_, _Rhynchogonium_, _Boroviczia_, _Diplopterotesta_, _Musocarpus_, _Holcospermum_. =Hexagonocarpus.= Renault. This generic name is adopted by Renault[1021] for casts from Commentry which, while probably identical with Brongniart’s _Hexapterospermum_, afford no confirmatory anatomical evidence. The species _Hexagonocarpus crassus_[1022] is represented by casts or nucules characterised by six well-defined ribs and grooves with a length of nearly 3 cm. In this genus may be included the cast from the Coal Measures of Lancashire described by Williamson[1023] as _Hexapterospermum Noeggerathi_ (fig. 506, H), and another British example is afforded by _Hexagonocarpus Hookeri_ Kidst.[1024], a rare fossil in the South Staffordshire coalfield. It is impossible confidently to assign these ribbed casts to genera founded on petrified specimens as they almost certainly belong to different types, but the employment of the name _Hexagonocarpus_ may conveniently be used for casts or impressions of seeds with six longitudinal ribs differing in their relatively broader and less prominent form from the wing-like flanges of _Polypterocarpus_ (cf. fig. 496, B). The seeds described by Dr P. Bertrand[1025] as _Hexapterospermum modestae_, and believed by him to belong to a plant with _Neuropteris_ fronds, should be included in _Hexagonocarpus_ as we have no definite knowledge of their anatomical features. =Decagonocarpus.= Renault. This name, proposed by Renault[1026], is applied to seeds without petrified tissues characterised by ten ribs; an example is afforded by _Decagonocarpus olivaeformis_ from the Commentry coalfield, an elliptical seed which bears a close resemblance to _Holcospermum sulcatum_ (fig. 506, A) except in the smaller number of ribs. =Polypterocarpus.= Grand’Eury.