Jurassic plants from Yorkshire, etc. 259 
Similar interstitial strands have been recorded in Ginkgodium 
by Yokoyama* and in some BaierasF., 
The cuticular preparations made from the leaves of this species 
are generally somewhat thicker than those from 4. pubescens. The 
cells of the upper epidermis were strongly cuticularised above the 
veins and somewhat elongated (ef. Pl. vu. fig. 8), while the areas 
between the veins were composed of more rounded cells with a 
convex outer surface; in this region stomata are frequently seen 
(fig. 9, st), which are much smaller than those on the lower epidermis. 
The distinction between the cells above and between the veins is 
much greater than in the Gristhorpe specimens. The lower 
epidermis consists of fairly uniform squarish or hexagonal cells 
all considerably thickened (fig. 6). The stomata are seen in the 
areas between the veins but are smaller and fewer in number 
than in E. pubescens, they show five or six subsidiary cells of the 
same type as in that species (fig. 7), and these sometimes possess 
small papillate projections though they are not specially thickened. 
The guard cells were sunken, being just visible through the pore 
in the centre of the overarching subsidiary cells. 
It will be seen from the foregoing description that the Whitby 
and Gristhorpe specimens exhibit some well-marked differences, 
chiefly in cuticular structure, but also in external appearance in 
well-preserved specimens. The resemblances and differences may 
be summarised as follows. 
ERETMOPHYLLUM gen. nov. 
Leaves oblanceolate to linear tapering into a distinct petiole. 
Apices rounded or retuse. Veins distant, dichotomising near base 
of lamina and more or less parallel above, slightly convergent near 
apex. Epidermal cells more or less rectangular or polygonal. 
Stomata with group of angular subsidiary cells regularly arranged 
round and above the guard cells. 
ERETMOPHYLLUM PUBESCENS sp. Nov. 
Surface of leaves appearing more or less smooth. No inter- 
stitial veins or strands. Secretory tracts present between the 
veins. Epidermal cells of upper surface uniform, without stomata, 
Cells of upper and lower epidermis with short papillae. Stomata 
numerous on lower side of leaf. 
ERETMOPHYLLUM WHITBIENSE Sp. NOV. 
Upper surface of leaves rough. Interstitial veins or strands 
present between the veins. Cells of upper surface elongated 
* Yokoyama (89), Pl. virt. figs. 1, la, 14, 14a. 
+ Kyrasser (05), p. 24. 
