Cavers : Notes on Yorkshire Bryophytes. 47 
cubical cells alternate regularly with the long undivided cells ; 
the former gave rise to the spores, the latterto g¢ § § § 
the elaters. The arrangement as seen in a cross einerve 
section of the capsule is shown intheaccompany- S S S § 
ing diagram; S=spore-forming and e=elater- eI e re 
forming cells. According to Leclerc du Sablon,* Sara: S015 
the spore mother cells and elaters lose their cell walls at one 
stage, and afterwards acquire fresh walls, but this seems to be 
an error, due, probably, to imperfect methods of preparation. 
The walls are mucilaginous, and stain deeply in microtome 
sections, but there appears to be a definite wall at all stages, as 
in other liverworts. 
The spores of /rul/anta are roughly spherical (but rather 
irregular owing to their becoming flattened by contact in the 
longitudinal rows), and about 1.06 mm. in diameter; the outer 
coat (exospore) is thick, brown in colour, and shows a number of 
shallow circular pits, the surface of which bears small tubercles. 
Each elater becomes somewhat flattened at the lower end ; 
it contains a broad brown spiral band, passing into a ring at 
the trumpet-like lower end (Fig. 7, AD). In the developing 
elater the protoplasm becomes differentiated into an axial strand 
and a peripheral layer, which becomes spirally wound on the 
inner surface of the wall (Fig. 7, A). The elaters show this 
stage, and are still colourless after the spores have acquired 
their final form, and have the outer coat fairly thick and golden- 
brown, so that the elaters keep for a long time their primary 
function of conveying food materials to the developing spores. 
The cells in the lower part of the fertilised archegonium (calyptra) 
contain dense protoplasm with oil-drops, as do the cells in 
the tissue of the thickened archegonium stalk. The elaters 
alternate regularly with the longitudinal rows of spores, con- 
sequently, those nearest the central line of the capsule are the 
largest. There are from 80 to 100 in each capsule in / dlatata 
and F. ¢famarisct. 
The wall of the capsule at an early stage becomes two- 
layered. The cells of the outer layer have thick rod-like fibres 
on their lateral walls, especially at the angles between adjacent 
cells; these rods appear as dots in a surface view of the capsule 
(Fig. 7, C), and are especially marked, and deeply coloured brown 
at the two opposite points at the bases of the valves into which the 
capsule wall splits (Fig. 7, E). On the walls of the inner layer 
of cells the thickenings form an irregular network (Fig. 7, D). 
* Annales des Sci., Nat., 1885. 
1907 February t. 
