showing the nucellar apex surrounded by radially disposed chambers (fig. 409), presents a certain resemblance to a synangium of _Telangium Scotti_; and it is suggested that the chambers encircling the nucellus may represent sterilised sister-sporangia[142]. ‘The seed in fact is assumed to be a synangium in which all but one of the sporangia are sterile, and form an integument to the one fertile sporangium which has become a megasporangium with one large megaspore.’ This view, though clearly incapable of confirmation in the present state of our knowledge, is not merely an ingenious hypothesis but a stimulating suggestion as to possible homologies: as an argument in favour of associating _Lagenostoma_ and _Telangium_ as the spore-bearing organs of the same plant it has but little weight. iv. _The Seed._ =Lagenostoma= Williamson. _Lagenostoma Lomaxi_, Oliver and Scott ex Williamson, +MS.+ In 1877 Williamson[143] proposed the generic name _Lagenostoma_ for some petrified seeds from the Lower Coal Measures of Lancashire and described two species, _Lagenostoma ovoides_ and _L. physoides_: in his +MS.+ Catalogue a third type is referred to as _Lagenostoma Lomaxi_. It is this third type that Prof. Oliver was the first to recognise as the megaspore-bearing organ of _Lyginopteris oldhamia_. Its structure has been thoroughly described by Oliver and Scott[144] and these authors contribute a judicial summary of the evidence on which _Lagenostoma_ and _Lyginopteris_ are believed to stand for one and the same plant. The evidence is based chiefly on the following considerations: an agreement in the structure of the vascular bundles in the investments of the seed with those in the leaves of _Lyginopteris_; the presence in the outer envelope of the seed of stalked glands identical with those on the stems and petioles. The evidence does not as yet amount to absolute proof, as the seeds, which occur either with or without a stalk, have not been found attached to a _Lyginopteris_ frond. But ‘where vegetative and reproductive organs presenting identical structural features, not known to occur in other plants, are thus found in close and constant association, the inference that the one belonged to the other appears irresistible.’ While most botanists believe that a satisfactory case is established there are a few[145] who refuse to believe in a connexion between _Lagenostoma_ and _Lyginopteris_ until an actual union has been demonstrated. The discovery by Kidston[146] of seeds attached to pinnae bearing _Neuropteris_ pinnules and the demonstration of organic continuity between seeds and the pinnules of other Palaeozoic fern-like fronds supply abundant confirmatory evidence that leaves no doubt as to the occurrence of seeds on modified pinnae of _Sphenopteris Hoeninghausi_ and of other closely allied fronds which represent the foliage of different forms of _Lyginopteris_. In this connexion it is pertinent to add that Grand’Eury[147] has found seeds