244 MISS H. BANDULSKA ON THE CUTICULAR STRUOTUKE OF 
has demonstrated that the same genus may have straight or sinuate walls to 
its epidermal cells in different species of fossil Ginkgo from the flora of the 
Inferior Oolite of Brora. Thus Ginkgo digitata had an epidermis, the walls 
of whose cells were sinuate, while Ginkgo biloba has cells whose epidermal 
walls are straight. 
Detailed Account of New Leaves. 
DicoTYLoPHYLLUM, nom. nov., for fossil dicotyledonous leaves of doubtful 
affinity. 
DicoryLOPHYLLUM STOPESII, sp. n. (Pl. 20. figs. 1-4). A single specimen 
was found by the writer in a clay boulder near the top of the West Cliff, 
about ten yards west of the West Cliff lift. 
External Characters.—Simple, lanceolate tapering; apex somewhat blunt ; 
coarsely serrate ; teeth comparatively wide apart, from 7 mm. near the base 
to 4 mm. near the apes. Venation unicostate, lateral veins well marked. 
Length 5:6 cm. ; width 1°6 cm. 
Cuticular Structure. 
Under Epidermis (Pl. 20. figs. 2, 3).—This consists of :— 
(i.) Thin-walled parenchyma: Cells somewhat longer than broad, on the 
average ‘025 mm. by ‘018 mm. These parenchyma cells are also associated 
to form hair bases. 
(ii.) Guard cells of the stomata associated with which are accessory 
epidermal cells varying in number from two to four or five. They bound 
open pores in the specimen examined. The stomata and guard cells are 
remarkably large. The average diameter of the latter parallel to the pore 
is ‘025 mm., and at right angles to the pore it 15:025 mm., hence the stomata 
are isodiametric. They are very close together surrounding the bases of 
hairs which are frequently separated by a single row of stomata only, at the 
most by three rows. The hairs, or rather the hair bases, consist of radially 
grouped epidermal cells surrounding an opening; the walls are strongly 
thickened along the radii, especially towards the centre. 
Upper Epidermis (Pl. 20. fig. 4).—The majority of the cells consist of 
ordinary epidermal parenchyma. There are numerous scattered hair bases, 
the average distance between which is ‘275 mm. The hair bases and the 
epidermal cells are similar to those described above. There are a few 
stomata, and thirteen or more epidermal cells intervene between them; their 
distance apart is very marked when compared with the close chain-like 
arrangement on the lower surface. | 
DICOTYLOPHYLLUM SPICULATUM, sp. n. (Pl. 20. figs. 5-9). One fairly 
complete specimen was found (see text-fig. 1), and many fragments in 
material communicated by Dr. Stopes. The leaf appears to have been 
extremely abundant, locally. 
