1 14 Scott and Mas ten — The Structure of Trigonocarpus . 
all probability Trigonocarpus Parkinsoni agreed with the modern Cycads 
in all these respects. 
After giving off the sarcotestal strands, the main bundle, accompanied 
by its parenchyma, continues unbranched through the stalk of the seed, 
until it passes into the nucellus and gives rise to the inner vascular system 
to be described later. At the bottom of the body of the seed a pad of 
parenchymatous tissue is frequently seen between the nucellus and the 
sclerotesta ; this tissue is doubtless continuous with the tissue which sur- 
rounds the vascular bundle of the stalk. Laterally this tissue may have 
been continuous with the presumed c inner flesh,’ or it may have narrowed 
down beyond the limits of the tracheal disk and become continuous with 
the hypoderm of the nucellus. On analogy with Stephanospermum 1 the 
latter view would appear to be probably the correct one. 
In PL XII, Fig. 12, the position of some sarcotestal bundles is 
indicated at s.b., s.b., and in PI. XIV, Fig. 25, this portion of the seed is 
shown magnified about eighty times. The tissues are very much disturbed, 
although the preservation of some of the elements is excellent. Parts 
of at least two and probably three sarcotestal bundles appear to be repre- 
sented at b., b., b. In places the dark-coloured hypodermal cells of the 
sarcotesta, //., have been pushed inwards until they are quite close to 
the bundles. Immediately surrounding the bundle on the right are the 
remains of a delicate cell-reticulum representing the tissue in which the 
bundles were embedded. Bounding the space in which the bundles are 
contained are some of the ordinary cells of the sarcotesta, sa. 
Scattered about in the fine tissue which separates the bundles are 
numerous short tracheides or transfusion elements, s.t., which remind one 
forcibly of the very similar elements contained in the fine conjunctive tissue 
surrounding the pairs of sarcotestal bundles in Cycas Beddomii. In this 
Cycad the two bundles of the outer flesh are complex in structure. Each 
is really double, and consists of two complete collateral mesarch bundles 
orientated with their phloems towards one another. The bundles are 
surrounded by a considerable development of very fine conjunctive tissue 
containing numerous transfusion tracheides with thickened walls and fine 
reticulate or spiral markings, and the whole is enclosed in a common sheath 
of relatively large cells with reticulately thickened dignified walls (see 
Miss Stopes’ paper, 1904, Fig. 8, p. 445). 
In Trigonocarpus Parkinsoni the sarcotestal bundles of the body of the 
seed are always very imperfectly preserved, but as far as the evidence goes 
a simpler type of bundle, such as is found in Cycas circinalis 2 , is indicated, 
rather than the complex one of Cycas Beddomii. In the longitudinal section 
shown in PI. XII, Fig. 12, and PI. XIV, Fig. 25, however, a more complex 
type of bundle may be represented. Comparing our PI. XIV, Fig. 25, with 
1 Oliver (’ 04 ) (1), p. 367 and PI. 43, Fig. 21. 2 Stopes (’ 04 ), p. 439. 
