Notes on Trigonocarpus and Polylophospertnum. ioi 
position so far as the pollen-chamber is concerned and probably 
the same is true of the body the nucellus. Its cells are very 
curiously modified, a large number, especially in the region of the 
pollen-chamber, projecting as dome-shaped pustules, the summits 
of which taper into aiguille-like pinnacles. In some instances the 
limiting membrane of the tapering portion seems to be resolved into 
a spirally running thread. The whole phenomenon, which is 
curious and unusual in this position, suggests that an expansion has 
occurred as a consequence of a mucilaginous break-down of the 
cell-contents, a break-down that may or may not have been con¬ 
nected with the activity of the putrifactive organisms that every¬ 
where riddle the tissues. 
In the nucellus itself the main interest centres in the strands 
of transfusion tracheides that run in the peripheral tissues. 
Elements from these strands are shown in photos. 6, 7, 8 
and 9. For the most part these tracheides have thickenings which 
are characteristically scalariform (photos. 7 and 8), occasionally 
they show a near approach to a reticulated type (photo. 6). Though 
in the main the strands run longitudinally, at places their course 
is not quite so regular and indications of cross connections occur as 
at A in photo. 9 (taken from specimen 1492b). Another strand with 
very distinct scalariform markings on the tracheides is reproduced 
in photo. 7 (from the same specimen). The tracheides themselves 
vary in diameter from 12 to 20/x, whilst in length an extreme 
fluctuation is found from long slender tracheides extending for \mm 
to such as have quite a short truncate outline. 
In their distribution in the nucellus the tracheal elements may 
be traced to a height distinctly above the open sac that represents 
the prothallium (Photo. 5, 0), so that it seems probable that they 
reached to the floor of the pollen-chamber, as in Stephanospermmii d 
In regard to the structure of the testa we have practically 
nothing to contribute. Everything is consistent with the distri¬ 
bution of harder and softer tissues indicated in Brongniart’s sketch 
of a transverse section of this seed. 2 The hexagonal stone 
(sclerotesta) is strongly ribbed along the angles, and the harder 
tissue of which it is composed consists of elegantly reticulated, 
oblong and pointed elements. The transition from this hard core 
to the softer enveloping “ sarcotesta” would appear to have been 
gradual. Whilst in specimen 1492 little of the latter remains, in 
1 Trans. Finn. Soc., 2nd ser. Bot. Vol. vi., p. 369. 
2 Foe. cit., pi. C., Fig. 7. 
