I 12 
Notes. 
structure is best shown in one of the original Hooker and Binney sections, now 
preserved in the Binney Collection at Cambridge. The presence of a beak is 
obscurely indicated in the Williamson section (C.N. 1478), shown in Fig. 114 
of his Memoir before referred to. The beak, as shown in the Binney slide, is 
barely half a millimetre in length, but presumably it extended much further in the 
natural condition. The cells of its outer wall are distinguished by their palisade-form, 
and there is an inner layer of prosenchymatous elements, apparently of the nature of 
tracheides. The resemblance to the Cordaitean pollen-chamber as shown in Renault's 
well-known figure 1 is rather striking, while there is also a fair agreement with the 
corresponding structures in a recent Cycadean ovule. 
The conclusions which we have so far reached as to the structure of Trigono - 
carport olivaeforme are thus the following : — 
1. The sarcotesta was differentiated into an inner, comparatively dense, and 
an outer, lacunar zone, the whole bounded by a definite hypoderma and epidermis. 
2. The nucellus, so far as can be ascertained, was free from the integument 
throughout its whole length. 
3. The pollen-chamber was provided with a beak or canal, comparable to 
that in Cordaitean and Cycadean seeds. 
4. The vascular system of the seed was a double one ; the outer system 
consisting of bundles running free in the sarcotesta, while the inner formed 
a complex tracheal reticulum in the nucellus, including definite longitudinal bundles, 
and thus differing from Stephanospermum where the tracheal mantle ‘ is a con- 
tinuous sheath without trace of local segregation into bundles V 
5. The two systems of bundles diverged from the chalazal supply-strand at very 
different levels. 
6. The tracheides agree closely in minute structure with the primary tracheides 
of Medullosa . 
The impression that Trigonocarpon is the seed of Medullosa has been gaining 
ground for some considerable time, although no evidence of actual continuity 
is known. The practically constant occurrence of Medullosa petioles ( Myeloxylon ) 
in slides showing Trigonocarpon , and the equally general association of the casts 
of the seeds with the pinnules of Alethopteris lonchitica , now known to belong 
to Medullosa , as well as the resemblance in the minute structure of the tracheides, 
all tend to make the presumption probably true. 
Mr. Wild, in his paper before referred to, emphasized the similarity between the 
outer tissues of Trigonocarpon and those of the petiole of Medullosa anglica , but, as 
has been indicated earlier in this note, with our present knowledge, the resemblance 
does not seem quite as close as he supposed, owing to the apparent absence of 
the small-celled epidermal layer in the petioles. 
It will be best to postpone any discussion of the affinities of the seed, until 
we are able to publish our work in full. 
D. H. SCOTT. 
A. J. MASLEN. 
Kew. 
1 Tiges de la Flore Carbonifere, PI. 17, Fig. 15. 2 Oliver, loc. cit., p. 367. 
