Scott and Mas leu . — The Structure of T rigonocarpus. x 29 
in the following way. The outer surface of the sclerotesta surrounding the 
micropylar canal is shown at s.t.b., the reference line passing to one of 
the longitudinal ridges of the micropylar beak (compare the transverse 
section across the lower part of the micropylar beak shown in PI. XI, 
Fig. 7). The beak shown in Fig. 16 gradually tapers upwards, so that 
while the width at the base is about 6 mm., at the upper end it is less than 
3 mm. These dimensions agree approximately with those of the sclerotesta 
shown in PI. XI, Figs. 7 and 8, from which it appears that these two 
sections were cut at a considerable distance from one another, perhaps 
nearly equal to the length of the micropylar beak shown in Fig. 16. The 
upper end of the micropylar beak of Fig. 16 has an unfinished appearance, 
probably because the distal portion, consisting of thinner-walled tissue, 
is lost. That the outer surface of the sclerotesta of the beak, and not that 
of an internal cast of the micropylar canal, is shown in Fig. 16, is made 
probable, then, by its size agreeing with that of the petrified specimens. 
The width of the base of the beak compared with that of the body of the 
seed also confirms this explanation. A typical transverse section across 
the body of the seed, such as that shown in PI. XI, Fig. 5, has a diameter 
(measuring to the outside of the sclerotesta) of about 1-3 cm., while the 
diameter at the base of the beak is almost exactly half this, and the same 
proportion holds good in the specimen represented in PI. XII, Fig. 16. 
On one side of the micropylar beak is seen a flat area (PI. XII, Fig. 16, sa.), 
which we interpret as the impression of the sarcotestal covering. The 
appearance presented might very well be due to a wing of soft tissue more 
or less ‘ doubled ’ under. This ‘ wing ’ cannot be traced with certainty below 
the beak portion of the seed. 
The body of this seed (Fig. 16) has such a form and dimensions as to 
quite well agree with the petrified specimens of Trigonocctrpus Parkinsoni . 
The body of the seed is split in such a way as to provide us with 
a tangential section showing the sclerotesta, s.t., preserved in coaly 
material which is continuous with the similar substance forming the micro- 
pylar beak, s.t.fr., and the material, c., filling* up the central cavity of 
the seed. 
PI. XII, Fig. 17, shows another seed impression which has a remarkable 
appearance of being complete, especially at the upper end, so that the whole 
seed has a symmetrical, elongated, oval outline. The body of this seed is 
about equal in width to that of the specimen shown in Fig. 16, but its 
length is about *5 cm. greater. The micropylar beak, m.fr., can be seen 
extending from the top of the body of the seed for a distance of 2*35 cm., 
preserving an almost equal size the whole distance. The lower (darker) 
portion of the beak, 1 cm. in length, is preserved in relief, and has a triangular 
form, with an edge or longitudinal ridge to which the reference line, m.fr., 
passes, and possibly another on the left of this. The upper (lighter) part of 
K 
