an archaic type of Seed from the Palaeozoic Rocks. 1 1 5 
Fig. 14. Portion of transverse section cut low down in seed, so that the embryo-sac appears filled 
with tapetal tissue (ip.) ; s.z. zone of secretory cells, projecting at places beyond the vascular 
strands (v.b.) ; l. lacuna between integument (mi.) and secretory zone : it is continuous at this level of 
the seed. U. C. L., R. 71 a (Shore), x 66 (see pp. 97, 99). 
Fig. 15. Transverse section of a somewhat compressed seed. Seven of the tentacles are free, 
whilst the four ribs at the bottom of the drawing are still confluent. The section is cut through the 
lower part of the pollen -chamber (p.c.), which contains several pollen grains, but to the right and 
below it passes out through the floor, sn. sinus ; mg. cavity of megaspore. The section is cut 
slightly above that given in Fig. 13. S. 1907 (Dulesgate). x 36 (see p. 85). 
Fig. 16. An oblique tangential section through the outer side and hairy covering of a tentacle. 
The upper two-thirds of the figure represents the sections of the tubular hairs belonging to the distal 
part of the tentacle. The hairs stand in longitudinal rows — well shown by the third row from the 
left-hand edge. t. filling tissue of tentacle; ep. epidermal cells; t.h. tubular hairs. U. C. L., 
R. 70, c (Shore), x 60 (see p. 88). 
Fig. 17. Median longitudinal section of the apex showing the orifice of the pollen-chamber 
(op.c.). On the left the insertion of the pollen-chamber wall has broken away from the nucellus. 
Five tentacles are shown above cut through in various directions, tp. s.z. black crust representing 
the tapetal and secretory zones. U. C. L., R. 90 (Shore), x 20 (see pp. 90, 91). 
Fig. 18. Median longitudinal section through an entire seed. The outer part of the integument 
is wanting except on the right, above. The pollen-chamber and its orifice (op.c.) are well shown, 
also the projecting papilla of the megaspore (mgp.). On the left of the concave floor of the pollen- 
chamber traces of the cushion are visible (cu.) ; sn. sinus. Above the pollen-chamber are portions 
of tentacles. S. i798'(Dulesgate). x 14 (see pp. 85, 90, 91). 
Fig. 19. Oblique section between seed-base and embryo-sac, showing ring ot xylem- strands not 
yet separated ( yb.r .) ; within this ring are crowded secretory sacs (j.j.) and a few stray ones outside. 
U. C. L., R. 73, c (Shore), x 46 (see pp. 96, 97). 
Fig. 20. Tangential section of the base of a seed. v.b. four vascular strands diverging from 
point of entry ; s.z. zone of secretory sacs. W. 1440 (Moorside). x 16 (see p. 96). 
Fig. 21. Longitudinal section of seed- base — almost median. The divergent bundles (v.b.) enter 
at the base ; around them the well-marked lacuna (/.) ; ini. tissue of integument ; s.z. secretory zone. 
U. C. L., R. 96 (Bacup). x 40 (see pp. 81, 90, 96). 
Fig. 22. Oblique tangential section through the base of a seed just grazing the embryo-sac. 
tp. tapetal layer ; s.z. zone of secretory sacs ; v.b. three xylem strands diverging ; /. lacuna ; int. 
tissue of integument ; above are traces of three ribs and tubular hairs (t.h.) cut transversely. 
U. C. L., R. 72, a (Shore), x 32 (see pp. 88, 90). 
Fig. 23. Transverse section across lower part of seed showing curiously preserved tapetum. 
tp} outmost layer of tapetum showing cellular characters as in the best preserved specimens; 
tp} inner structureless zone of tapetum, where the cells have collapsed ; tp} peculiar striated type of 
preservation — very commonly fringing the embryo-sac : the striae are readily mistaken for tracheal 
sculpturing ; s.s. secretory sacs. U. C. L., R. 74, a (Shore), x 200 (see p. 98). 
PLATE VII. Figs. 24-30 (Drawings). 
Fig. 24. Section through the tapetal zone from near the base of a seed : the radial files of cells, 
though distorted, are manifest, i.s. inner margin bordering on the embryo-sac; o.s. outer margin 
bordering on the secretory zone. U. C. L., R. 98 (Dulesgate). x 180 (see p. 98). 
Fig. 25. Oblique transverse section across a pollen-chamber showing the tapetum ot the 
apical papilla of the embryo-sac in a dilapidated state, p.c. pollen-chamber ; tp. tapetum, torn and 
distorted ; c.a.p. cavity of apical papilla. U. C. L., R. 97 (Shore), x 86 (see p. 99). 
Fig. 26. Transverse section of a portion of a tentacle showing the epidermis and filling tissue — 
the cells of the latter with contracted vesicles, i.e. epidermis of inner (adaxial) side ; th. proximal 
ends of tubular epidermal hairs on convex (abaxial) side ; ft. filling tissue ; l. lacuna. The vascular 
strand is not preserved. U. C. L., R. 75, d (Shore), x 200 (see pp. 88, 89,97). 
Fig. 27. Part of scalariform tracheal element. S. 1753 (Dulesgate). x 400 (see p. 96). 
Fig. 28. Transverse section of a vascular strand with the accompanying lacuna and tissues — from 
the mid-height of a seed. tp. tapetum ; s.z. secretory zone ; v.b. xylem strand ; l. lacuna ; r.f. cells 
I 2 
