THE PALZEOZOIC SEED LAGENOSTOMA OVOIDES. 463 
В. Internal. 
The bulk of the orthotropous seed is occupied by the nearly spherical 
nucellus, which itself was almost entirely filled with the megaspore, Аз 
before stated, the nucellar apex was modified into a flask-shaped organ, the 
wall of which was bevelled, except at the base, in correspondence with the 
fluted internal wall of the micropyle, beyond which it projected, expanding 
slightly (Pl. 28. fig. 9). The base was a trifle constricted, and the actual 
pollen-chamber, which frequently contains pollen-grains, was formed by the 
separation of the specialized wall of the lagenostome from the central cone 
of tissue. The crevice thus produced was, in mature specimens, in direct 
communication with the exterior, since the wall does not extend over the 
projecting tip of the organ, though whether it did so in the young condition 
there is no evidence to show. Closely investing the nucellus, and adherent 
to it for nearly three-quarters the length of the seed, is the integument, which 
thus far is a relatively simple shell, but above the point at which it becomes 
free from the nucellus expands into a somewhat complicated structure. 
The hard shell was continued as far as the micropyle, from which point it 
was reflexed upon itself, running inwards and downwards to the nucellus in 
the form of a fluted layer, the concavities of which were directed outwards. 
The form of this internai wall of the upper, free part of the integument 
cannot be better pictured than by the original simile of “an umbrella being 
opened against a gust of wind,” the “ ribs" of which are united to the shell 
towards the apex, but free below. A number of loculi, distinct above, 
though fused tangentially below, were thus formed, the radial septa of which 
were overarched by the external ridges. The actual number of loculi varies, 
but is usually 8, though it may be 7, and is rarely 6 or 9. It has been found 
possible to count accurately the number of loculi (or of vascular bundles) in 
twenty-three different seeds: of these, twelve showed 8 loculi, six had 7, two 
had 6, and two had 9; the remaining specimen, Н. 20 б (1) (РІ. 28. fig. 16), 
formed a pretty transition between the most usual numbers by possessing 
six normal loculi, and a seventh and eighth fusing to form a double loculus 
traversed by two bundles in close proximity. These two bundles аге shown 
lower down side by side in the body of the seed in R. 20 « (1). 
Lining the hard shell of the integument, where the latter is confluent 
with the nucellus, are a few layers of soft tissue, whieh were continued 
into the space between the two hard layers of the free part and up 
into the apical loculi. This tissue is very rarely preserved; it is well 
shown at the base of the seed in В.20а (1), and through the whole course 
of the upper part of the integument right into the loculi in tlie oblique 
section R. 205 (1). 
The vascular system is very simple: a single bundle enters the seed at 
the chalazal papilla, and, after traversing the hard shell, divides into a 
2x2 
