37(^ T. G. IIALLE. [Nov. 1913. 



It is true that VtUopliylhim as originally defined would em- 

 brace also fronds of the type in question. But, as in the case 

 of Zaniitcs and other old genera of C^^cadophytean fronds, it 

 has become necessar}^ to substitute a more distinct definition 

 for the original one: otherwise the genus would come into 

 collision with other genera now commonl}^ accepted. This 

 has been done by Feistmantel, whose definition of the genus 

 seems to meet the most important demand to be made on a 

 new definition of an old generic name, viz. to be based on the 

 specimens for which the name was created.^ AVith exception 

 of the numerous illustrations given by Feistmantel of the 

 Indian species of FtUophylhwi, very few forms of that genus 

 have been figured with due regard to the shape of the pinna- 

 bases. In addition to a reproduction (PL 9, fig. 1) of one of 

 Feistmaxtel's figures of Ftnophyllum aciitifoUum I have there- 

 fore given, in PL 9, figs. 2 — 5, some photographs, in twice the 

 natural size, of the pinna-bases of one of the English forms 

 of the genus. This form, which is one of those commonly 

 known among English palaeobotanists as Williamsonia pecten^ 

 is identical with Cycaditcs pectinoides Phillips and should 

 be named Ftilophyllum pectinoides (Phill.) Morr. It is 

 seen from the figures to show the generic character of Ftilo- 

 phyllani in Feistmaxtel's sense by having an asymmetric 

 pinna-base with both edges decurrent on the rachis. And it 

 must be admitted that this is a very characteristic type of 

 pinna-base which well deserves to be distinguished from that 

 of typical Zamites species, such as Z. gigas. 



In order to decide whether the Antarctic species of Zamites 

 should be retained in that genus as a somewhat less typical 

 group or included in PtiloplnjUnm, they should be compared 

 with typical specimens of these two genera. The text-figures 



^ Regarding the relation of Feistmantel's definition to Morris' type-speci- 

 mens see Halle, T. Gr.: Some plant-bearing deposits in Patagonia and Tierra 

 del Fuego and their floras. K. Sv. Vet. Akad. Handl., Bd 51, N:o 3, 1913, 

 p. 36. 



