Although it is not certain that these seeds are morphologically identical with the genus _Lagenostoma_, a brief description is intercalated here as the habit of the seed-bearing axes supplies a probable key to the habit of the fertile fronds of _Lyginopteris_. The type-specimens were collected by Mr Sinclair from the Lower Coal Measures of Ayrshire, Scotland, and recorded by Kidston as _Lagenostoma_ sp.: they were afterwards named by him in manuscript _L. Sinclairi_ and handed to Dr Arber for description. The seeds are elliptical-oblong, 4–5·5 × 1·5–3 mm., radially symmetrical and enclosed by a loose envelope which is longitudinally ribbed and divided distally into several linear-lanceolate lobes (fig. 408, A, A′). This covering, though much longer than the cupule of _Lagenostoma Lomaxi_, is probably a homologous structure. The most interesting point is the attachment of the seeds to slender branches of a compound axis (fig. 408, A). It is probable that the seeds were borne on a frond characterised by the reduction or complete abortion of the sterile lamina or perhaps, as in the recent Fern _Thyrsopteris elegans_[180], some of the pinnae of a large compound frond were fertile. It is worthy of note that Arber recognised pinnules of _Sphenopteris obtusiloba_[181] in association with _L. Sinclairi_, a fact, as he says, in itself of no value but which acquires significance in view of the discovery by Carpentier[182] of cupules in close proximity to the same species of frond. Specimens described by Dr Stopes from Westphalian rocks of New Brunswick as _Pterispermostrobus bifurcatus_[183] bear a close resemblance to _L. Sinclairi_. _Lagenospermum oblongum_ (Kidston). The species recently described by Dr Kidston[184] as _Lagenostoma oblonga_ from the South Staffordshire coal-field appears to be closely allied to Arber’s _L. Sinclairi_: it is represented by pairs of seeds borne at the ends of forked branchlets: the seed is 2·5 mm. long by 1·5 mm. broad and is surrounded by a longer oblong cupule divided distally into 6 free lobes. A larger type of seed, 3 cm. long and 2·5 cm. broad, is described by Kidston[185] from the same coal-field as _Lagenostoma? urceolaris_. A characteristic feature is the truncate apex surrounded by a prominent canopy formed of the expanded apical free portion of the integument. The lack of anatomical data in both these seeds is a reason for the substitution of some less committal term than _Lagenostoma_. Grand’Eury[186] and Carpentier[187] have published accounts of impressions of seeds from the Coal Measures of France compared by them with species of _Lagenostoma_ though not assigned to new species. These and similar seeds should be referred to Nathorst’s genus _Lagenospermum_.