374 PROF. F. W. OLIVER ON THE STRUCTURE, 
S. akenioides (65 mm. in S. caryoides, 1°6 mm. in S. akenioides). This difference probably 
corresponds with a difference in actual life in conformity with the absence of a micropylar 
beak. That the tuft represents a hairy plume seems improbable ; its structure suggests 
a fibrous cushion, when some organ, now lost, may have been attached to the seed. 
Though there is no evidence to show that the surface of the seed was covered by a 
fleshy sarcotesta, there is nothing inconsistent with such a view should it seem probable 
from analogy with other seeds of like organisation. In this connection, however, see the 
remarks concerning A. akenioides (p. 366). The base of the most nearly median of the 
sections does not, unfortunately, coincide with the entering bundle, but there is no 
reason for supposing it to have departed materially from the type. 
Endotesta. 
A Layer within the Sclerotesta—Of the existence of an endotesta beneath the 
sclerotesta there are some traces. There are, lining the carbonised epithelioid layer 
of the sclerotesta, definite traces of a thin-walled tissue (text-fig. 2, end.t.). These 
fragments are of the nature of a flattened macerated cell-reticulum, which appears to 
have been continuous with the epithelioid layer of the sclerotesta, but the discovery 
of additional specimens must be awaited before it is possible to speak confidently of the 
nature and extent of the endotesta in this seed. 
Nuceellus. 
The Nucellus stands up freely from the base of the seed with a wide space between it 
and the sclerotesta. It shows the usual segmentation into prothallial and pollen- 
chamber regions. The embryo-sac is nearly globular, there being but a trifling 
difference between the transverse and vertical diameters. The pollen-chamber region is 
also broad and large, but its height, though actually exceeding that of the corresponding 
structure in S. akenioides, is, relative to the height of the whole nucellus, less than in 
that species. Here it is about 4, in S. akenioides about + of the whole. The summit of 
the nucellus tapers suddenly, 2. e. into a short apieulus, the actual extremity of which is 
not, unfortunately, included in any of the sections. Consequently it must remain 
a matter for later determination whether the nucellar beak ended approximately as 
shown in Pl. 42. fig. 17 (at a), as seems probable, or whether it was continued further in 
the direction of the micropyle. The curved sides of the pollen-chamber are included in a 
well-marked epidermis consisting of cubical cells on the flanks, but becoming more 
columnar as the insertion of the beak is approached. This is well shown in PI. 44. fig. 938, 
a faithful rendering of the top of the nucellus under a magnification of 65 diameters. 
The pointed summit is therefore surrounded by a circular zone of enlarged columnar 
epidermal cells suggesting the annulus in one of the Schizæaceæ. The sloping sides of 
the pollen-chamber are very well preserved in this seed, and consist of thin-walled, 
spindle-shaped cells, well shown in PI. 42. fig. 17 and in more detail in fig. 18. The long 
axes of these cells converge towards the apex. The walls show occasional pitting, and in 
the parts adjacent to the macrospore a folding of the walls, as of a tissue which had lost 
its turgidity previous to fossilisation. The dome-shaped cavity of the pollen-chamber is 
