KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 51. N:o |0. 11 
Frond pinnate, comparatively broad; length up to 30 cm. Rachis stout, bi- 
furcating, bearing pinnae both below and above the point of bifurcation. Pinnae 
close, pointing slightly upwards, long and usually falcate; first linear then rapidly 
narrowing; or tapering from the very base and obliquely triangular; distal margin 
concave or sometimes straight, running out into an acute or blunt apex; proximal 
margin rounded at least in the upper part of the pinnae. Venation, when distinguish- 
able, consisting of a number of fine, forked, parallel veins coming direct from the 
rachis. Consistence not very thick. 
The cuticle is generally comparatively thin. It is of the same thickness on 
both sides or somewhat thicker on the upper one. The cells are irregularly poly- 
gonal. The cuticle of the upper side is uniform and devoid of stomata. On the 
lower epidermis sometimes there are, and sometimes there are not, strips of oblong 
cells corresponding to the course of the veins, and between these or over the whole 
surface are found a greater or less number of stomata (pl. 2, fig. 7; see p. 4). 
The general rule is: the thinner the cuticle, the smaller the number of the stomata. 
Holes occur in the cuticle in some instances (see p. 4). 
Since NATHORST instituted Pt. fallax, the collection of fronds representing 
this species has considerably increased. Some specimens (pl. 1, fig. 8; pl. 2, fig. 6) 
are very beautiful and fairly complete, and give a good idea of the appearance of 
the frond. As is the case with Ptilozamites Nilssoni this species has a forked rachis. 
The most characteristic features are the breadth of the frond, the shape of the 
pinnae, the indistincetness of the venation, and the relative thinness of the cuticle. 
The variation presented by different specimens is not very great. It consists prin- 
cipally in a somewhat different shape of the pinnae, these being falcate in some 
instances, and in others possessing straight, distal margins; in some cases they taper 
from the very base, and in others only near the apex. Towards the lower part of 
the frond the pinnae grow shorter and broader, and often assume an almost 
triangular shape. 
Pt. fallax is rather closely related to Ptilozamites Nilssomi. The two species 
are, however, at the same time well distinguished, the forms which can be compared 
being on one side — Pt. Nilssoni — the extremely large ones, on the other side the 
comparatively small ones, whereas the typical representatives show less resemblance. 
Those specimens which agree in habit can also be distinguished, Pt. fallax having 
less distinct veins and being of somewhat thinner consistence. 
Pt. fallax is only known from the Rhaetic deposits of Scania, where it is 
pretty common in the plant-bearing layer 4 at Bjuf. Less frequently it occurs in 
strata 3 and «2 in the same locality. One fragment comes from Bjuf 2. Finally, 
specimens were found at Billesholm and one fragment in the lower seam at Höganäs. 
(Bjuf 2, zone with Dictyophyllum exile. Höganäs the lower seam, and Bjuf 1—3, 
zone with Camptopteris spiralis. Bjuf 4, zone with Lepidopteris Ottonis.) 
