JURASSIC PLANTS FROM CROMARTY AND SUTHERLAND, SCOTLAND. 869 
with those of Conifers than with the larger stomata of Cycads. The marginal band 
(text-fig. A, B, b) resembles that in some larger specimens referred to Thinnfeldia 
rhomboidalis Ett. from English Liassic strata,* and, though much narrower, is 
comparable with the thickened margins of the pinnules of Jurassic species assigned to 
the genus Lomatopteris. In Thinnfeldia scotica, as in the English T. rhomboidalis, 
the dark marginal band is simply the thickly cuticularised epidermal layer at the edge 
of the lamina, and is not due to any folding over of the pinnules. The lines traversing 
the marginal band seen in text-fig. 1, B, are breaks in the membrane and not cell-walls. 
In habit, Dr Natuorst’s specimen resembles Thinnfeldia incisa Sap.,t a French 
Liassie species, but it differs, apparently, in the absence of lateral veins. 
Dr GotHan{ has recently instituted a new generic name Dicroidiwm for such 
forms as Thinnfeldia odontopteroides (Morr.); this southern-hemisphere type GoTHAN 
distinguishes from the true Thinnfeldias for the following among other reasons: in 
Dicroidium the frond is forked, the epidermal cell-walls are thin and undulate, the 
stomata are scattered and not enclosed by accessory cells as in Thinnfeldia. It is by 
no means unlikely that the southern species Thannfeldia odontopteroides is a well- 
defined type distinct from European examples of 7hinnfeldia, but for the present we 
prefer to suspend judgment as to the validity of the arguments advanced by Dr GorHan 
in favour of the institution of a new generic name. In the Scotch fragment the stomata 
are scattered and not in rows, a character associated by Goran with Dicroidium, 
though it may well be the case that the arrangement in rows is not a constant feature 
in Thinnfeldia. It is, moreover, open to question whether the European Thinnfeldia 
fronds are always unbranched: a specimen previously described from Sutherland§ as 
a piece of Thinnfeldia exhibits a form of branching like that of 7. odontopterordes, 
though it must be admitted the reference to Thinnfeldia rests on unsatisfactory 
evidence. Whether or not Dr Goruan’s conclusions are confirmed by fresh discoveries, 
his critical examination of the impressions hitherto included in Thinnfeldia is a very 
welcome contribution. The evidence at present available is inadequate to anable us to 
define with confidence either the systematic position of the fossils referred to Thinn- 
feldia, Dichopteris, Lomatopteris, etc., or to make any definite statements as to the 
value to be attached to the generic distinctions implied by the use of these different 
designations for fronds of the Thinnfeldia type, whether simple, forked, or tripinnate. 
CONIFERALES. 
Brachyphyllum eathiense sp. nov. (Text-fig. 5, A, Pl. I. figs. 2-4.) 
1857. “Imbricated stem,” Miller, Testimony of the Rocks, p. 491, fig. 149. 
1911. Brachyphyllum sp., Seward, Trans. Roy. Soc. Edin., vol. xvii. p. 683, pl. ix. fig. 33. 
The specimen from Kathie, figured by Mituer half natural size, though very in- 
completely petrified, reveals on microscopical examination certain features worthy of 
* SEwARD (04), pl. iv. figs. 1-3. + Saporta (73), pl. xii. 
{ Goran (12) ; see also Goran (12°). § Srwarp (11), p. 678 ; pl. vii. fig. 14, 
