132 FITTOXIA. 



of difference, and considers that Mantell's specimen has heen 

 correctly made the type of a new genus. In Buclclandia the 

 stem appears to have been frequently branched, but no such 

 habit is indicated in the specimens of Fittonia in the latter 

 genus the increase in size both of the petiole and scale-leaf 

 bases, and of the lower portion of the petioles as well as the 

 scale leaves, with the subsequent disarticulation of the upper 

 part of the frond axis, constitute constant and characteristic 

 features. The pith is large and surrounded by a narrow zone 

 of wood. The scale leaves, associated here and there with the 

 bases of fronds, are distinguished from the latter by their 

 thinner distal margins, and the absence of any distinct surface 

 of articulation. As Saporta remarks, there is a striking re- 

 semblance between some forms of Fittonia and Buclclandia ; this 

 similarity has already been noted in the descriptions of some 

 of the Museum examples of the latter genus, and it is also 

 clearly seen in Carruthers' type specimen in the Jermyn Street 

 Museum of Practical Geology. It may be that the two genera 

 are not really distinct, but merely represent different forms of 

 preservation of very similar, if not identical, plants. In describing 

 the single English specimen of Fittonia, Mantell quotes the 

 opinion of Brongniart, 1 to whom a drawing of the fossil was 

 sent, that it is probably the upper portion of a clathrarian 

 stem with persistent petioles. It may be. more convenient, with 

 the evidence at present available, to retain both generic names, 

 and to make use of Fittonia as a useful designation for a certain 

 form of cycadean trunk. 



Fittonia Ruff or di, sp. nov. 



[PL IX. Fig. 6.] 



Type. Large impressions of stems. British Museum. 



The lower portion of the petioles persistent, showing a well- 

 marked surface from which the upper part of the frond has 

 been detached. The persistent and swollen bases are regularly 

 disposed in the stem surface, and apparently without any 

 alternation of petiole scars and scale-leaf scars. 



r _ 1 . . __^_ 



1 Mantell (A. 7), Geol. Excurs. I. Wight, p. 298. 



