Trigonocarpus Skorensis, sp. nov. 61 
such ridges, corresponding to both the major ribs preserved, can be distin- 
guished. Such commissural ridges , 1 2 3 of which an example is figured in 
PI. V, Fig. 13, n.f.) from section S. 31, e y furnish the strongest evidence 
that the nucellar surface was in the mature condition in close contact with 
the sclerotic testa, a point Avhich the well-developed cuticle further 
emphasizes. 
VI. The Pollen Chamber. 
Our information respecting the structure of the pollen chamber is 
extremely meagre, as only two sections furnish data of any importance. 
The general form of the pollen chamber, as seen in S. 32, c , is rectangular, 
with longer sides forming the roof and floor (3 mm. wide x 1*26 mm. high). 
As will be seen from the diagram, the direction of the section passes 
tangentially through the pollen chamber in a plane slightly oblique to that 
of a minor rib. 
The central part of the roof in this section shows a triangular, blunt- 
ended, upward projection of the epidermis, which may be the base of the 
micropylar tube. 
The epidermis of the pollen chamber is continuous with that of the 
nucellus, and the component cells up to about half its height are of the same 
form in both. Beyond this point they become much larger (o-o 66 mm. radial 
by 0-04 to 0-08 mm. vertical), with thinner walls, and do not possess the black 
carbonaceous contents present in the lower part. The increased size is 
especially noticeable where the sides curve inwards to form the roof ; these 
shoulders project somewhat laterally, partly owing to the larger size of the 
epidermal cells and partly to the slightly greater internal diameter (PI. V, 
Fig. 11). The blunt apex of the angular projection is formed of cells which 
are much narrower in the tangential direction, 0-005 mm. Interiorly, the sides 
of the pollen chamber were occupied by a soft parenchymatous tissue, con- 
sisting of elongated cells with tapering ends. This is most pronounced in 
the shoulders, and the appearance presented very closely resembles that 
described and figured for other seeds of this affinity, as for example 
T. P 'ctrkinsoni? T. piisillus? Aethiotesta , 4 and Stephanospermum . 5 
In S. 32, /*, the pollen chamber exhibits a prominent angle corresponding 
in position to a major rib, and also in Section I of Dr. Scott’s series the 
shoulders appear double-angled, the lower of the four angles being the true 
1 Cf. Renault : Angling of Nucellus in Trigonocarpus pusillus. Flore fossile d’Autun et 
d’Epinac, pt. 2, p. 39S. 
2 Scott and Maslen, loc. cit., p. 121. 
3 Oliver: New Phyt., vol. iii, 1904, PI. II, Fig. 3. 
4 Renault : M^m. Soc. d. Sci. Nat. de Saone-et-Loire, 1887, Pl. XVI, Fig. 3. 
5 Oliver: Trans. Roy. Soc. Lond., p. 370, PL XLII, Figs. 11 and 18. 
