Bd. III: 14) 
THE MESOZOIC FLORA. 
51 
related if not identical. The difference would seem to be that the one species 
hitherto described of Ctenopsis has the veins arranged in pairs, the distance between 
the veins in each pair being only one third of that between the pairs. It seems 
very doubtful to the present writer whether this character is sufficient for generic 
separation or not. In the forms here referred to Psezidoctenis the veins occasionally 
start in pairs from the rachis, but a little further out the two veins of a pair are at 
the same distance from each other as the other veins. At any rate it is clear that 
the forms here described under the name Pseudoctenis should be referred to that 
genus and not to Ctenopsis^ even though the habit is perhaps more like that of the 
type-species of the latter genus. 
Pseudoctenis ensiformis n. sp. 
PI. 6, fig. 8. 
Ptcrophyllum, Nathorst fig. in; O. Nordenskjöld. J. G. Aniiersson etc. 1904, pi. facing p. 318. 
A fine specimen of a frond represented by both counterparts has been referred 
to this new species. 
Frond large, 12 — 14 cm. in breadth at least. Rachis rather slender, 2 — 3 mm. 
broad on the impression. Pinnæ at right angles to the rachis, inserted laterally by 
the whole of the base, which is expanded, with both the edges of the pinna con- 
tinuing on the rachis sometimes to the next pinna. Pinnæ broadly ensiform with 
somewhat obtuse apex, not ribbed. Veins parallel, strong but not very thick, distant 
about I — 1.5 mm. from each other, mostly simple; bifurcation occurring about once 
or twice in each pinna. 
The peculiar habit of this frond is due chiefly to the shape and to the mode of 
attachment of the pinnæ. These taper gradually from the base, but in a character- 
istic manner, the distal edge being comparatively straight and the proximal one 
bending forwards to meet it, the lamina thus becoming short ensiform. Another 
characteristic feature is the widening of the pinnæ at the base, both edges bending 
outwards and sometimes nearly joining those of the next lower and higher pinnæ, 
thus forming a rounded sinus. To this feature corresponds a peculiarity in the 
course of the veins: the uppermost one or two veins in each pinna do not bend 
downwards when joining the rachis, as do the others, but upwards, parallel with the 
distal edge of the pinna. This is well seen in the figure, especially in the lowest 
pinnæ. The veins are always distinct and well marked, but not very thick; and 
they do not project much above the perfectly plane surface of the lamina. They 
are remarkably distant in relation to their small thickness. As is seen in the figure, 
branching of the veins occurs only rarely and irregularly, most of the veins being 
simple and strictly parallel. Sometimes they start in pairs from the rachis, but more 
