THE PALJEOZOIC SEED LAGENOSTOMA OVOIDES. 477 
seen that it shaves the canopy lining without touching the lagenostome, and 
we know, therefore, that the plinth in its central part is cut exactly tan- 
gentially to the axis of the seed (cf. its plotting on p. 464). In this region 
we see that the vertical walls are strongly thickened, while the thin horizontal 
(external) walls are curved inwards (РІ. 24. fig. 33). On either side the 
projecting vertical bars may be seen of cells which have either lost their 
outer horizontal walls or, more probably, these have sunk inwards so far 
that they are not readily discernible. The bars are about 9 р across, and 
are thus seen to be less thick than those of the lagenostome, with which, 
however, they are in direct continuity. This is well shown in several 
fortunate sections, whose planes include the junction of the plinth and the 
lagenostome (В. 27, В. 46). 
Surface view of part of lagenostome wall (х 360). 
The epidermis of the plinth was thus composed of radially elongated cells 
with thickened vertical walls, and apparently lay directly over the nucellar 
membrane. 
D. The Pollen. 
There is little to say under this heading, for though the pollen leaves 
nothing to be desired in quantity, the same cannot be said in respect to its 
quality. It occurs in several slides of the Williamson Collection and in 
many preparations belonging to the University College Collection, but is 
never really well preserved. 
LINN. JOURN. — BOTANY, VOL. XL. 2 т, 
