547 
Diitt. — Pityostrobus macrocephalus , L. and H. 
absent. It may be noted, also, that Radais, speaking of the anatomical 
distinctions between the two sections of Pinus , remarks the absence of resin- 
canals from the vascular system of the scales, and apparently also from the 
wood of the axis in the section Strobus ( 12 , p. 278)* Resin-canals are, how- 
ever, present in the wood of the cone-axis of the species Pinus excelsa. On 
the whole, the anatomical characters of P. macrocephal agree with those 
of species belonging to the Strobus section, and, while there is no very close 
agreement with any of them, the fossil seems to have more in common 
with Pinus excelsa , L., than with any of the others. 
The following diagnosis is based on the cones here considered : 
Pityostrobus macrocephalus , L. and H. Cone ovoid-cylindrical, apex 
obtuse. Length 15 cm. or less. Breadth 5 cm. Axis very slender, 
surrounded by a conspicuous ring of resin-canals. Scales leave axis almost 
horizontally and then ascend sharply beyond the seeds, which are borne in 
dairs in hollows on the upper surface near the base. Apophyses thick, flat, 
quadrangular or irregularly hexagonal. Basal scales with large apophyses. 
Short bracTscale. Ovules, two on each scale, 1 cm. long by o-6 cm. in 
breadth. Stone layer corrugated. Seeds usually barren. 
Summary. 
The paper gives a detailed description and comparison of the internal 
anatomy of two forms of cone occurring in the Lower Eocene of the London 
Basin. 
Two separate species, Pinites macrocephalus, Carr., and Pinites ovatus, 
Carr., have been founded on the slight differences in external appearance, 
but the close resemblance in internal structure justifies the conclusion that 
they are specifically identical. 
The new aggregate species has been called Pityostrobus macrocephalus , 
L. and H. 
The cone exhibits several interesting anatomical features. The cone- 
axis is very slender and has a weakly-developed xylem cylinder which 
contains neither resin-canals nor resin-parenchyma, but resin ‘ spools * are 
present in ordinary tracheides. A conspicuous circle of resin-canals 
surrounds the axis, and from their number an accurate determination of the 
phyllotaxis of the cone can be deduced. 
The cone-scales are of the normal Pinus type, a short bract-scale being 
present. The cone is* however, peculiar in the large size of the lowermost 
seed-scales. 
The most important observations have reference to ovular structures. 
The ovules are provided with a thick, differentiated integument with a long, 
almost closed micropyle. They represent nearly mature, winged seeds, but 
are usually barren and with the contents little shrunken. 
The nucellus is marked by a peculiar apical column of tissue. Winged 
