THE PALZEOZOIC SEED LAGENOSTOMA OVOIDES. 471 
which are roughly circular in outline though of very different sizes, varying 
from 20-50 ш in diameter. The cells are all thin-walled with intercellular 
spaces, and occasionally show pale brown contents. 
There is no section across the body of the seed where the soft tissue is well 
preserved : it is indicated at one place in transverse section (R. 24), and in 
one or two longitudinal sections such as В. 48 (2) several wavy outlines 
within the fibrous layer represent its disorganized remains. Most oblique 
sections of the canopy have traces of the filling tissue, and in the second of 
the exquisitely preserved seeds in К. 206 it is perfectly shown. — In this 
section we see ata glance that the soft tissue was not really parenchyma, 
since comparatively few transverse walls are seen across the delicate 
elements, whieh were elongated in a direction parallel with the wall of the 
seed. The cells are more uniform in size here than at the base and measure 
20-25 u in diameter. As in the case of the fibres, itis not possible to determine 
their length in the absence of a suitable preparation ; but in one oblique 
section an element was found at least 170 р long, and they perhaps reached 
a greater length than this, though the impression is given that they were 
not so long as the fibres. 
In very many sections there is in the remains of this tissue а well charac- 
terized type of cell, which will be here termed the secretory sac. Р]. 22. 
fig. 6 shows two of these elements with a little of the adjacent tissue, 
oceurring at the baseof R. 41 (2). The walls are always very thin, and generally 
pale, though distinct. The contents are very dark indeed, and almost, if not 
quite, homogeneous, a very small space being left between the contents and 
the wall usually around its whole extent. Although, of course, it is impossible 
to be sure what secretory sacs should look like in a fossilized condition, yet 
this appearance is quite what one might expect. The homogeneity of the 
contents suggests that nucleus and plastids, ete. had disappeared, giving place to 
а substance or mixture of substances rich in carbon, and easily breaking 
down with heat, such as sugars and some organic acids, which are just what 
is found in the secretory tissue of recent plants. The thin walls also accord 
with the secretory nature of the cells in question. The sacs are well shown 
in the British Museum slide 1885 B (text-fig. 2, p. 473) ; and in sections of 
the roots of the plant, or close relation of the plant, which bore our seed, 
occurring on the same slide, cells of precisely similar general characters are 
found which are stated by Scott (17, p. 239) to be probably secretory sacs. 
The same well-defined type occurs constantly in the débris round the seeds— 
for instance, in sections of pinnules (cf. Pl. 28. fig. 10) which were very pro- 
bably the foliage of the plant bearing the seeds, and it is difficult to think of 
any other type of cell which these elements could represent. The sacs, which 
are often of considerable length, 75 р or more, are irregular in shape, and 
seem to occur on the outer and inner limits of the soft tissue in the canopy. 
