114 MR. E. A. NEWELL ARBER ON TRIASSIC SPECIES 
Description of the Specimens. 
The lanceolate or linear-lanceolate pinna* figured on Pl. 17. fig. 1, reduced to half 
natural size, is almost complete, with the exception of a small portion of the apex, 
which is missing. It measures about 37°5 em. in length, and 4°6 cm. across at its 
greatest width. At the base it narrows somewhat sharply to a breadth of 1-4 cm. The 
basal callosity is not very evident in the photograph. The general parallel course of the 
nervation can be made out fairly clearly in this specimen. The surface of the leaflet 
shows numerous puckerings, which are also evident on nearly all the examples of this 
frond. ; 
An even larger pinna T is figured on Pl. 17. fig. 3, also reduced to half natural size. 
It is an almost complete leaflet, except that a small part of the base and a portion of the 
apex are wanting. It is the largest example obtained from Worcestershire. The 
complete pinna must have been nearly 50 em. in length, and was about 6'7 cm. across 
at its greatest breadth. At the base it contracts to between 2-3 cm. in width. 
The lanceolate form of the leaflet is striking and the nervation is fairly clear. 
Another specimen f, a basal portion of a pinna, is figured on PI. 17. fig. 2, natural size, 
to show the nervation. It measures 23 cm. in length, and 5:5 em. at its broadest part. 
The nerves appear to be stout and close, and are strictly parallel, with occasional 
dichotomy. 
On the same specimen there is also another fragment of a pinna, 21 cm. long, in which 
the apex is quite complete. This is figured on Pl. 18, fig. 2 (natural size). The 
acuminate and elongate extremity of the pinna, ending quite acutely, is here well seen. 
The leaflet appears to be somewhat falcate in its upper portion, though this feature is 
not very evident in the present specimen owing to a slight distortion, due to the 
unevenness of the surface of the marl on which it rests. The curious puckered appearance 
of the surface of the leaflet, of frequent occurrence, is specially noticeable in this example. 
The photograph on Pl. 19. fig. 1 shows the apical portion of an almost complete leaflet 
(natural size) §, which had become bent upon itself before incrustation took place. The 
entire pinna in the living state probably exceeded 40 cm. in length, with a maximum 
breadth of 55 em. The apex is wanting. An excellent example | of an apical portion 
in which the actual tip of the leaflet is also missing is seen on Pl. 19. fig. 3 (natural 
size). It measures 14 cm. in length, and 5'5 cm. at greatest breadth. The falcate 
form of the apex is well shown. 
The photograph on Pl. 19. fig. 2 (natural size) shows a basal fragment €, about 
8 cm. in length, of a rather small leaflet. The thickening or callosity at the base is 
clearly seen. Another basal portion ** (Pl. 17. fig. 4), belonging to a still more slender 
pinna, shows the callosity, and also the contracted nature of the base of the leaflet, 
though the nervation is only very faintly marked. 
* No. 24. British Triassic Plant Coll., Sedgwick Museum. 
T No. 25. Ditto. i No. 26. Ditto. $ No. 22. Ditto. 
|| No. 27. Ditto. «| No. 28. Ditto. ** No. 90. Ditto. 
