1 12 Scott and Mas ten . — The Structure of Trigonocarpns. 
is at about that distance from the base of the sclerotesta of the body of the 
seed. 
Passing to the transverse sections of the base of the seed we have 
in PL XI, Fig. i, a section which is doubtless cut across the lower part of 
the stalk, probably about on a level with its lower end, as shown in the 
longitudinal section, PI. XII, Fig. 12. In the section shown in PI. XI, 
Fig. i, the whole of the outer portion of the sarcotesta has been destroyed 
with the exception of the characteristic outer limiting layers, which have 
evidently suffered much displacement by compression from without, as they 
are, in places, repeated as many as four times. The tissue preserved is 
mainly composed of thin- walled cells which pass gradually into the sclerotic 
tissue which surrounds the triangular space, b., containing the entering 
vascular bundle. No trace of bundles or tracheides can be seen in the 
sarcotesta of this slide, probably because the section is just below the level 
at which the sarcotestal bundles are given off from the main bundle. The 
triangular form of the space in which the main bundle is contained is 
probably of some significance, especially as this form is much less marked 
in sections across the upper part of the stalk, such as the one shown 
in PI. XI, Figs. 3 and 4. There is evidence from the longitudinal sections 
that the sarcotestal bundles were given off from the main bundle at a con- 
siderable distance below the base of the body of the seed, although, 
unfortunately, no section shows the actual branching. In the section 
figured in PI. XII, Fig. 12, sarcotestal bundles can be seen in the slide 
at the points marked j. b., s. b ., and one of these is figured in detail in PI. XIV, 
Fig. 25, which will be described later. From the position of these bundles 
in the stalk it is clear that the)/ must have arisen some distance below the 
level at which they are seen in PI. XII, Fig. 12, so that the junction with 
the main bundle must have been at least 4 mm. below the base of the 
nucellus. 
It is probable that the section which is shown in PI. XI, Fig. 1, is cut 
quite near to the level at which the sarcotestal bundles are given off, and 
that the triangular form of the space is to be correlated with this fact. 
The six sarcotestal bundles may have been given off in pairs corresponding 
in position with the angles of the space, or they may have been only three 
in number, each afterwards dividing into two. That the section is below 
rather than above the plane of branching seems evident from the entire 
absence of sarcotestal bundles, since the preservation of the inner tissues of 
the testa is so good that they would almost certainly be seen if they had 
been present. 
PI. XI, Fig. 2, shows the central part of Fig. 1, magnified about 
100 times. The xylem of the main supply bundle is preserved (£.), and has 
a width in the longest direction of -28 mm. The surrounding thinner- 
walled tissue has been entirely destroyed, but presumably it was a similar 
