In an exceptionally well preserved specimen recently described and admirably illustrated by Mr McLean[152] part of the parenchymatous tissue of the prothallus which originally filled the megaspore is clearly seen: its surface-layer consists of small cells succeeded by a broad band of radially elongated elements closely resembling the alveoli in the prothalli of some recent Gymnosperms, particularly certain Conifers. No archegonia have been discovered. The cupular envelope of immature seeds, compared by Oliver and Scott with the lobed and glandular husk of _Corylus colurna_ L.[153], receives several vascular bundles of collateral and mesarch structure from the axial strand, and these subdivide as they ascend. The glands which occur on all parts of the cupule are sessile or stalked and identical with those on the vegetative organs of _Lyginopteris_. Assuming that pollination occurred at a comparatively early stage in the development of the seed when the cupule was still intact, it is conceivable, as Sir Joseph Hooker suggested, that the glandular secretion may have attracted insects and so aided in the transport of pollen which were perhaps drawn down the narrow pollen-chamber by exuded mucilage as in recent Conifers. The evidence obtained in recent years in favour of insect-pollination in certain Cycads and in _Welwitschia_ lends support to this view: the dragon flies hovering over a fertile _Lyginopteris_ frond in a recent restoration[154] may be a legitimate addition. A striking feature of _Lagenostoma_ as of other Palaeozoic seeds is the absence of an embryo: this and other considerations have led certain authors, notably Chodat[155], to question the justification for the use of the term seed. Various suggestions have been offered in explanation of this fact. In recent Cycads, as already pointed out, the development of the embryo does not always occur before seed-fall. It may be that these older seeds had no resting-period or there may have been a period of rest after fertilisation and not as now at a stage subsequent to the formation of the embryo[156]; it is also suggested by Scott that ‘the nursing of the embryo had not yet come to be one of the functions of the seed, and that the whole embryonic development was relegated to the germination stage[157].’ In this connexion reference may be made to a statement by Miss Gibbs[158] who speaks of seeds of a _Podocarpus_ picked up from the ground in apparently a mature state and with the associated bracts coloured and swollen as though ready to aid in dispersal but with no embryo: the seeds had matured before fertilisation and fell from the tree after pollination. Whatever may be the true explanation of the absence of embryos this negative character should not be allowed to outweigh the evidence furnished by morphological features as to the applicability of the term seed. As Prof. Oliver says, ‘there is a long chapter in evolution to be deciphered before we can connect ...