In 1827 Buckland[1074] proposed the generic name _Cycadeoidea_ for some petrified stems from the Purbeck beds in the Isle of Portland and published a description of two species, _Cycadeoidea megalophylla_ and _C. microphylla_. Brongniart[1075] considered Buckland’s term _Cycadeoidea_ inappropriate and proposed in its place _Mantellia_, the type-species being _Mantellia nidiformis_ Brongn., the Portland stem which Buckland a month or two later called independently _Cycadeoidea megalophylla_. Subsequently Brongniart[1076] withdrew _Mantellia_ as it had been previously used by Parkinson for a sponge and substituted _Cycadites_. Some years later Carruthers[1077] revived _Mantellia_ for a type of Cycadean stem from Portland though one species, apparently indistinguishable from those referred to _Mantellia_, he named _Bennettites portlandicus_. There is no adequate reason for the retention of the generic name _Mantellia_. The close resemblance of the short and thick stems (12–30 cm. in height) described by Buckland to those of some recent Cycads was recognised by Robert Brown and Loddiges and the former suggested to Buckland the inclusion of the fossils in a new family Cycadeoideae. It was this suggestion that led Buckland to adopt _Cycadeoidea_ as a generic name. In a later account of the Portland stems Buckland[1078], in deference to Brongniart’s opinion, substituted Brongniart’s name _Cycadites_ for _Cycadeoidea_. It is noteworthy that no reference is made in the original description to the occurrence of lateral shoots among the persistent petiole-bases that encase the Portland stems, but in a later account such shoots are represented in one of the figured stems and are compared with the buds occasionally produced on stems of _Cycas_[1079]. The subsequent researches of Carruthers[1080] demonstrated the reproductive nature of precisely similar lateral shoots in the stem on which he founded the genus _Bennettites_. The generic name _Echinostipes_ given by Pomel[1081], who had a passion for instituting new nomenclature, to Buckland’s Portland stems has not been adopted: his genus _Crossozamia_ proposed for certain stems and fronds was revived by Carruthers[1082] but has not been generally used. A further complication in the nomenclature of Cycadean stems was introduced by Saporta’s institution[1083] of _Bulbopodium_ and _Cylindropodium_: in the former genus he included the small ovoid stem figured by Lindley and Hutton as _Cycadeoidea pygmaea_[1084] and two French Jurassic species which might reasonably be assigned to _Cycadeoidea_. To _Cylindropodium_ were referred some large French stems from Jurassic strata: an examination of the type-specimens in Paris convinced me that they are typical forms of _Cycadeoidea_. As Ward[1085] has pointed out, both Saporta’s genera may be merged in _Cycadeoidea_. Fliche and Zeiller[1086] also include the small globular stems named by Saporta _Bulbopodium_ in