364 
Proceedings of the Royal Society of Edinburgh. [Sess. 
Almost every feature in the sporophyll of Spencerites, as seen in radial 
section, except the protuberance of tissue bearing the sporangium, is paralleled 
by the radial section of L. cernuum, if we assume the removal or dis- 
appearance of the structureless mucilage from the latter. The relation of 
the pedicel-like portion of the sporophyll to the distal portion, the shape of 
the latter, and the marginal appendage, all appear to correspond. The 
position of the sporangium is essentially similar, though it is somewhat less 
distal in L. cernuum. The close correspondence between the two sporo- 
phylls appears to justify the suggestion that in Spencerites, as in L. cernuum , 
the peltate appearance of the sporophyll is in the main of secondary origin, 
and is due to the disappearance of a mucilage cavity from a large 
sporophyll-base, leaving only the pedicel and the outer abaxial portion (the 
dorsal lobe), with which the lamina is continuous. The similarity of the 
marginal appendage shown in Miss Berridge’s reconstruction to that seen in 
L. cernuum (fig. 1, m.a), further suggests that in Spencerites, as in the 
recent plant, this fitted in between the sporangium and sporophyll verti- 
cally below. The fact that in the fossil it appears to have rested in the 
mature cone, not against the sporangium but on the ventral outgrowth, may 
indicate that the origin of this outgrowth was subsequent to that of the 
sporangium in the ontogeny. If this interpretation of the sporophyll of 
Spencerites be correct, the sporophyll would be in great part pseudo-peltate, 
and the sporangial insertion would be distal on the sporophyll-base and not 
on the lamina, which would bring Spencerites into line with other Lyco- 
podiales in this respect. 
The view just expressed, that the sporophyll of Spencerites owes its shape 
to the disappearance of a mucilaginous portion of the sporophyll-base before 
fossilisation, might be advanced on the comparison of the radial sections in 
the fossil and in L. cernuum, even if the sporophylls in Spencerites were 
throughout free from one another. The justification of the comparison is, 
however, increased by the existence of evidence pointing to the sporophylls 
of Spencerites having been coherent in a similar manner and degree to those 
of L. cernuum. This possibility of coherence of the sporophylls is not 
entertained in the later accounts given by Scott and Berridge, but was 
stated by Williamson in his first account of this cone.* He there figures a 
cross-section of a strobilus (toe. cit., PL 22, fig. 53), and says regarding it: 
“ The section, fig. 53, appears to have been made near one extremity of the 
strobilus, where some of the discs seen at the right-hand part of the figure 
are in close contact with each other (53, c), and in some cases these sporangio- 
phores are actually confluent (53, <?'").” This section (Williamson Coll., 626) 
* “Organisation,” Phil. Trans., Part ix., 1878, p. 341. 
