THE PAL-EOZOIC SEED LAGENOSTOMA OVOIDES. 467 
and darkening the cell-contents *. The middle lamella is possibly represented 
by the delicate line seen between adjacent cell-walls (cf. Oliver (13), pl. 49. 
fig. 22 and pp. 365 & 399). 
In only one case (В. 22) has а different type of preservation been noted, 
and here the walls appear darker than the contents, which were apparently 
not very great (Pl. 22. fig. 2). It is, perhaps, unnecessary to attempt to 
account for this appearance, since although the preparation is very perfect in 
some respects, the epidermis is not at all well preserved. 
Even a small fragment of the epidermis of Lagenostoma ovoides would 
serve to distinguish the species from L. Lomazü, since the cells of the former 
are much shorter and also quite destitute of the © pegs "—5o usual a feature 
in the latter species. 
It is, however, probable that there was a similar, if less elaborate, method 
of mucilage production, В.20а (1) and R.22 show “ blisters”? on the 
epidermis projecting into the organic débris surrounding the seeds, recalling 
those of L. Готаей (16, р. 206), and probably analogously produced by the 
emission of mucilage—not from a specialized external layer, but by the 
epidermal cells themselves. In В. 41 (1) we have several stages in this 
mucilage excretion, where the cuticle is seen raised to varying heights 
(РІ. 24. figs. 21 & 22). The slight raising of the cuticle over the papillate 
cells to the left is probably not an incipient stage, as the characteristic dark 
lines indicative of mucilage are not present. It has perhaps been raised 
by the expansion of the mucilage in its near vicinity ; or, since the cuticle is 
sometimes found exfoliated from the epidermis for long distances (R. 40, 
R. 43) without any apparent mucilage excretion, it may, with these cases, 
be an effect of mineralization. 
The mucilage in this species does not form distinct cones, as in L. Lomaai, 
though it is possible that it was given off in spiral, rope-like bands, as in the 
recent seed of Collomia. This is suggested in К. 48 (3), and also by the 
dark transverse bars seen on the cones of L. Lomacii (К. 8 b), indicating that 
the mueilage here may have had some such differentiation. In this connection 
we must remember that, as Oliver and Scott point out, we have probably 
in these seeds “a sporadic and premature manifestation of a phenomenon 
which normally became general only at a later stage in the history of the 
seed " ; and this is borne out by the fact that in L. oroides, as in their species, 
the discharge of mucilage, quite limited in extent, frequently occurs close to 
a local injury. (Cf. Pl. 24. fig. 27, though the details are too small to be well 
seen.) 
Gii.) The Fibrous Layer.—This is composed of thick-walled, prosenchymatous 
* Decayed tissue, at least in its first stages, will sometimes show points of structure better 
than when fresh. I found that certain partially lignified cells in water-plants stained best in 
specimens where decay had obviously set in, 
