CLADOPHLEBIS. 101 



1877. Pecopteris exiliforme, Geyler, Palseontographica, vol. xxiv. p. 226, 



pi. xxx. fig. 1. 



1878. Pecopteris polymorpha, Dupont, Bull. Ac. R. Belg. ser. ii. vol. xlvi. 



p. 387. 



1889. Aspidium Dunkeri, Fontaine, Potomac Flora, p. 101, pi. xxii. fig. 9; 



pi. xxv. figs. 11 and 12; pi. xxvi. figs. 2, 8, 9, 18; pi. liv. 

 figs. 3 and 9. 



Pecopteris Browniana (in part), Fontaine, loc. cit. p. 88, pi. xxiii. 

 fig. 6 ; pi. xxvi. figs. 3 and 13. 



1890. Pecopteris exilis, Yokoyama, Journ. Coll. Sci. Japan, vol. iii. p. 35, 



pi. i. figs. 8-10. 



1890. Pecopteris Geyleriana, Nathorst, Denkschr. k. Ak. Wiss. math.-nat. 

 Cl. vol. Ivii. p. 48, pi. iv. figs. 2-6. 



Type. Imperfect fragments of pinnae . 



Dunker founded the species Pecopteris polymorpha on a few 

 fragments of a frond from the North German Wealden ; some years 

 later Schimper altered the name to P. J)unkeri, because Dunker's 

 specific name had been previously used. The following definition 

 of the species by Schimper corresponds closely with the original 

 description as given by Dunker : 



" Fronde bi- vel tripinnata, pinnis patentibus, circa 2-3 cm. 

 longis, alternis ; pinnulis inferioribus oblongis repando-incisis, 

 superioribus oblongis, obtusis, approximatis, terminalibus conflu- 

 entibus ; nervis indistinctis ; rachi primaria sulcata, rachibus 

 secundariis tenerrime striatis." L 



I have adopted the generic name Cladophlebis in the absence of 

 any fertile pinnules with characters sufficiently distinct to allow 

 of reference to a genus suggestive of natural affinity. 



Frond tripinnate, rachis of medium breadth, pinnae approximate, 

 alternate and spreading, giving the whole frond a somewhat 

 deltoid form, tapering rapidly towards the apex ; pinnules small, 

 entire and somewhat falcate, attached by the entire base, or longer 

 and lobed, and narrower towards the point of attachment ; venation 

 indistinct, midrib fairly well marked. 



If Schenk's figure of Cladophlebis Dunkeri* be examined carefully, 

 it will be seen that the tripinnate character gives place to the 

 bipinnate form in passing from the lower to the upper end of the 

 axis, on the right-hand side of the specimen. The parts towards 



1 Trait, pal. veg. vol. i. 1869, p. 539. 



2 Palaeontographica, vol. xix. pi. xxvi. fig. 1. 



