34 BRITISH EOCENE FLORA. 



Middle Bagshot, Bournemouth, 



The specimen figured is apparently of delicate texture, and may be either the apex 

 of a barren frond or the fragment of a pinna. The pinnules are lanceolate and gradually 

 attenuated towards the apex, entire or slightly undulate, broadest at the base, and con- 

 fluent. The uppermost pinnules are attached at acute, and the others at about right 

 angles. The midrib is thin and tapering ; the secondary veins, ten or twelve in number 

 on each side, spring at angles of 50° — G0°, and are mostly forked. The venation is of 

 the true Alethopteris type. The apparently thin texture may be due to the long 

 maceration to which the leaf has evidently been subjected. 



The specimen so closely resembles the figures of P. (Eningensis^ lJnger,i that, judging 

 from them alone, it might be placed with it. That species, however, is of a more 

 coriaceous texture, and appears only towards the second part of the Miocene. In 

 connection with it Saporta has kindly communicated that he considers P. (Enivc/ensis^ 

 which appeared late in the Miocene, to be the forerunner of P. aquilina, and that the 

 Miocene form was preceded by P. uropliylla, and this by P. Aquensis and P. caudigera 

 of the Aix beds. The type of P. aquilina is probably very ancient, and may reasonably 

 be looked for in formations as old as the Lower Eocene. Debey thinks he has a similar 

 type from Aix-la-Chapelle. 



This Eern, which differs essentially from the P. eoccnnica, is known from a single 

 fragment only, met with among dicotyledons in a leaf-bed on the coast near Poole 

 Harbour. Fig. 7 is drawn the natural size; 7 a shows a portion magnified. 



The determination of this as Pteris is not absolutely certain in the absence of 

 fructification, as the venation is common to many Ferns. 



(d) Jspleniea. 



AsPLENiTES PRiE-ALLOSTJROiDES. Mt. and Gard. Plate III, figs. 1, 2. 



A.fronde memhranacea^ tripinnata, pinnis hijnnnatis patentihus, pinnulis stipitatis, 

 ellipticis, subobtusis, tenuissime crenulatis, sorts oblongis, biserialibus ; nervatione Cras- 

 pedopteris vera, nervo primario tenui, infra apice evanescente, nervis secundariis tenuis- 

 simis, simplicibus. 



Middle Bagshot, Bournemouth. 



The specimen appears to be the remains of a fertile frond, and recalls a somewhat 



1 Heer, ' Flor. Tert. der Schweiz,' vol. i, p. 39, pi. xii, fig. 5. 



