1 1 8 Scott and Mas fan. — The Structure of Trigonocarpus . 
displaced, which can scarcely be the case as the tissues are fairly well 
preserved. 
It is from the examination of sections such as those shown in Figs. 7-10 
(and there are others which exhibit the same features), that the opinion has 
grown that the long micropylar region of Trigonocarpus Parkinsoni was 
provided with a broad wing continuous with the outer layer of the testa. 
We have found it impossible to satisfy ourselves on the question 
whether the wing is a natural structure or is merely a result of the flatten- 
ing of the soft tissues of an originally cylindrical sarcotestal investment of 
the micropyle. In all the sections which we have examined there has cer- 
tainly been much loss of tissue ; sometimes, as in parts of PI. XI, P'ig. 8, 
where the limiting layers of the sarcotesta are pressed into contact, the whole 
of the tissue between has disappeared. In the section represented in 
PI. XI, Fig. 8, the total spread of the wings, allowing for the overlap, 
is about 31 mm. Supposing the epidermis filled out to form a circle 
(i. e. with no wings) the circumference would be about 45-50 mm., which 
would correspond to a diameter of about 14-16 mm. The seed represented 
in PI. XI, Fig. 5, has an average diameter of about 17 mm., but as the 
outer part of the sarcotesta has been destroyed the diameter in the original 
condition would doubtless have been somewhat greater than this. Anyhow, 
the measurements show that if the seed remained circular at the micropylar 
region there was only slight diminution in size up to the levels represented 
by PI. XI, Fig. 8, and PI. XII, Figs. 9 and 10. On the other hand, if the 
wing is natural, its spread would have been greater than the diameter of the 
seed below, which seems very unlikely to have been the case. Taking an 
intermediate view, that the wings had been somewhat reduced in thickness 
and exaggerated in spread, we might suppose that the maximum diameter 
of the seed remained almost constant up to the level of these sections, the 
micropylar region being flattened instead of cylindrical. 
On the circular hypothesis the epidermis, in such a section as PI. XI, 
Fig. 8, must have been squashed in upon the micropylar boss, for the diameter 
here would have been more than double what it is now. Unfortunately, 
a critical section is not available, as in no slide is the preservation of the 
tissues sufficiently good to enable us to trace continuity of structure between 
the sclerotic tissue of the boss and the dark hypodermal layer of the sarco- 
testa. That there has been loss of tissue is certain, but the structure does 
not suggest so great a displacement as is necessitated on the circular hypo- 
thesis. In other sections, also, the limiting layers of the sarcotesta round 
the micropylar boss seem to be in nearly their natural position. 
On the other hand, the fact that somewhat wing-like appendages may 
be produced by mere pressure is demonstrated in sections taken across the 
stalk, or even the body of the seed. PI. XI, Fig. 5, shows a small ‘ wing 5 
on one side, while PI. XI, Fig. 3, from the stalk of the seed, exhibits 
