122 MR. E. A. NEWELL ARBER ON TRIASSIC SPECIES 
Though the matter can hardly be said to be finally proved at present, there appears to 
be a very strong probability that the leaf of this species was really a pinnate frond, and 
that, like Zamites grandis, the large leaflets frequently became detached from the rachis, 
as in the case of several of Bronn’s figured examples. The arrangement of the leaflets 
in the specimen figured here (Pl. 18. fig. 1), although the fossil is admittedly imperfect, 
in conjunction with the frond described by Bronn, in which the pinne are still attached 
to the rachis, will hardly permit of any other conclusion, though the question cannot be 
finally settled until more complete specimens have been obtained. 
In this view of the Raibl specimen, I am in agreement with Schenk *, who in 1865 
decided that its affinities lay in the direction of the Cycadophyta, and corrected Bronn’s 
specifie determination. Schenk further concluded provisionally that the fossil most 
hyllum, and adopted the new name P. Bronni, which 
is that provisionally made use of here. There are only two other fossils with which I am 
acquainted which at all resemble this plant. One of these is the Sphenozamites 
Rogersianus of Fontaine +, from the Triassic rocks of the Richmond coalfield in Virginia, 
U.S.A. Fontaine's figures do not, however, agree very well with the Austrian specimen, 
though Sturt has gone so far as to say that both are specifically identical. Yet as 
regards generie affinity, the two plants are obviously closely related. In the size and 
shape of the leaflets, the American specimens show a striking agreement with Bronn’s 
species, especially as regards the apex. The basal characters are, however, different, 
judging by Fontaine's figures, which show pinn:e attached only by a small portion of 
the base, the upper and lower basal angles of which are rounded. In the specimen 
described here the pinnve are strictly wedge-shaped, and apparently attached by their 
entire base. The nervation also differs. In the Austrian specimen, no trace of trans- 
verse striæ between the nerves can be detected, and the veins pursue a more parallel 
course direct to the apex, and do not radiate as in the figure of the American plant. 
This frond, however, as a whole, supports the conclusion as to the pinnate nature of the 
leaf described here. 
The other species, Sphenozamites tener of Compter §, from the Keuper of Thüringia, 
is considerably smaller than the Raibl specimen, and does not appear to be very closely 
related. The first specimens figured were fragmentary, and consisted for the most part 
of detached pinnz. In these the shape is rhomboidal rather than cuneate, and the 
nervation appears to approximate more closely to that of the genus Sphenozamites. 
Compter also figures the cells of the epidermis of the leaflets, which he points out are of 
the Cyeadean type. A further specimen, figured by the same author in 1894, has several 
fragments of pinnæ united to the rachis. On the whole it shows obvious points of 
agreement with the figures of S. Rogersianus given by Fontaine, though it is no doubt 
a smaller plant specifically distinct. 
nearly approaches the genus Ptero, 
* Schenk (1865), p. 18. 
t Fontaine (1883), p. 80, pl. 43. fig. 1, pl. 44. figs. 1 & 2, pl. 45. figs. 1 & 2. 
$ Stur (1888), p. 210. 5 
$ Compter (1883), p. 12, pl. 1, «nd text-figs. 10-17, and Compter (1894), p. 222, pl. 4. fig. 3- 
