Fossil Floras of Cape Colony. 51 



divergent veins. Species of Padiijptcris or Dlchoptcris in whicli 

 the ultimate segments possess spreading and forking veins bear a 

 marked resemblance to TJiinnfcldia ; it is probalilo that the two 

 genera are very closely allied. 



Schimper, in the second volume of the " Trait6 de pal^ontologie 

 vegetale,"''' extends Ettingshausen's definition, and compares Thinn- 

 feldia with Pachypteris and Cycadopteris. In 1867 Schenk described 

 specimens of Thinnfeldia from the Khaetic beds of Franconia and 

 published figures of the epidermal cells and stomata ; he placed the 

 genus among the Cycads. f 



Bornemann,:[: in 1856, published figures of the epidermis of 

 Scytophyllum hcrgeri Born., a plant bearing a close resemblance 

 to Thinnfeldia, which may be compared with the drawings repro- 

 duced in pi. ix., figs. 7 and 8. Solms-Laubach ;; notes the occurrence 

 of stomata on both sides of the lamina of Thinnfeldia as a character 

 which may possibly indicate that the genus may not be a fern ; in 

 other respects the fern-like nature appears to be clearly indicated. 



Another genus — Ptilozamites of Nathorst — differs from Thinn- 

 feldia in the greater parallelism of the veins in the pinnules, but 

 in other respects there is a striking agreement between the two 

 genera, and it is doubtful if there are sufficient grounds for regarding 

 the slight difference in venation characters as more than a specific 

 distinction. A comparison of Nathorst's figures of species of Ptilo- 

 zamites from the Ehaetic of Bjuf :| and the Thinnfeldias of South 

 Africa represented in pis. vii. and viii. demonstrates the similarity 

 between the Northern and Southern types. Gutbier's Permian 

 species, Odontopteris rcichiana*' is another type wdiich exhibits 

 a very close resemblance to Tliinnfeldia. Another plant which I 

 venture to think should not be separated from Thinnfeldia has 

 been described and figured by Sellards from Permian rocks of 

 Kansas as Glenopteris simplex/'-''- In speaking of the characters 

 of this new genus Glenopteris the author notes its resemblance 

 to Loniatopteris and Cycadopteris, but does not refer to Thinnfeldia. 

 It is not clear that the institution of Glenopteris was a necessary 

 addition to palseobotanical nomenclature. 



Similarly some of the Italian species of Dichoptcris of Zigno and 

 species referred by Saportaft to Loniatopteris and Cycadopteris may 

 well be generically identical with Ettingshausen's genus Thinnfeldia. 



* Schimper (70), p. 494. t Schenk (67), p. lOo, pi. xxvii. 



X Boraemann (o6), pi. vi., figs. 1-0. S Solms-Laubach (<J1), p. 140. 



II Nathorst (78), pis. xii., &e. 'i Weiss (69), pi. i., figs. 3-9. 



** Sellards (00), pi. xxxix. ft Saporta (73), p. 340. 



