868 PROFESSOR A. C. SEWARD AND MISS N. BANCROFT ON 
adequate reason for placing on record such information as can be extracted from the 
imperfect specimens in our hands. Further search on the shores of Kathie Bay and in 
the neighbourhood of Helmsdale may enable us to make good some of the many 
deficiencies in the present contribution. 
DESCRIPTION OF THE FOSSILS. 
FILIcaLEs or GyMNOSPERM&: (°). 
Thinnfeldia scotica sp. nov. (PI. I. fig. 1; text-fig. 1.) 
1911. Thinnfeldia sp., Trans. Roy. Soc. Hdin., vol. x\vii. p. 676, text-fig. 7. 
We are indebted to Dr Narnorsr for the photograph reproduced in fig. 1, Pl. I, 
and for a cuticular membrane ofa single pinnule which on treatment with chlorate of 
potassium and nitric acid showed very clearly the form of the epidermal cells and 
stomata. The specimen was collected by Dr Natuorst near Helmsdale in 1883. 
The linear segments, the lower margins of which are decurrent on the broad and 
flat axis, are characterised by short, bluntly rounded lobes, thick and straight epidermal 
Trext-FicurE 1.—TZhinnfeldia scotica sp. nov. Cuticle showing cell outlines and the thick broad 
cuticularised marginal band. 
= 
cell-walls, by the occurrence of numerous scattered stomata occupying two broad strips 
on the lower surface of the lamina, and by the presence of a cuticular border (‘05 mm. 
broad) at the edge of each leaflet (text-fig. 1, A, B). 'The middle region of each 
pinnule is occupied by a broad band of elongated cells, and on either side of this the 
epidermis consists of smaller polygonal cells which are not elongated parallel to the 
long axis of the pinnule. ‘The stomata show no tendency towards regular arrangement 
in rows: each pair of guard-cells is enclosed by five or six cells as in Rheetic species of 
Thinnfeldia described by Scuenk* and other authors. It is noteworthy that the 
stomatal guard-cells with the enclosing auxiliary cells bear a closer resemblance to those 
of Gymnosperms than to the stomata of Pteridophytes ; in size they agree more closely 
* Scuunk (67), pl. xxvi. figs. 4-8 ; pl. xxvii. figs. 8, 11, 12. 
