It is not an easy task even for those most familiar with Carboniferous fronds to distinguish clearly between species agreeing generally with _Sphenopteris Hoeninghausi_, a species regarded by some authors as the type of a group of very similar and closely allied forms all of which were probably borne on stems referable to the genus _Lyginopteris_. The species _Lyginopteris oldhamia_ as generally understood probably includes more than one specific type, and it is safe to assert that in the Carboniferous period _Lyginopteris_ was represented by several forms characterised by highly compound fronds with forked rachises like _Sphenopteris Linkii_, _S. Hoeninghausi_, and others. The features characteristic of fronds included in the _Sphenopteris Hoeninghausi_ group have recently been described by Gothan[129]. Stur’s generic name _Calymmatotheca_ originally applied to the species _C. Stangeri_ was applied to _Sphenopteris Hoeninghausi_ by Zeiller, and although the fronds of the latter type have not been found with fertile appendages of the _Calymmatotheca_ type there can be no doubt as to the generic identity of these, barely distinguishable, species both of which belong to stems of _Lyginopteris_. Prof. Johnson[130] has recently described some impressions from the Coal Measures of Ireland, which he refers to _S. Hoeninghausi_, bearing stellate groups of lobes like those of _Calymmatotheca_, and in one case he describes a seed in the middle of the carbonised remains of a stellate group of cupular segments. An examination of the specimen in Dublin convinced me that there is no satisfactory evidence of the seed-nature of the appearance on the rock believed by Johnson to be an elliptical _Lagenostoma_-like seed. The actual attachment of the stellate lobes to the pinnae of the frond is not clearly demonstrated. iii. _Microsporangia._