132 SAGENOPTEBIS 



In Velenovsky's contribution to our knowledge of the Gymno- 

 sperms of the Bohemian Chalk formation there are several figures 

 of what he calls Thinnfeldia variabilis, Vel. ; the characters dis- 

 played by this species appear to me identical with those of the 

 larger leaflets of Sagenopteris Mantelli. There is the same 

 venation, the same form of leaflet, and an equally marked 

 variation in shape and size : of. Velenovsky's figures' and PI. IX. 

 Figs. 4 and 5 of this Catalogue. 



Why the genus Thinnfeldia, Ett., should have been chosen is 

 a question not readily answered ; no mention is made of a resem- 

 blance to Sagenopteris, and there is a great dearth of references 

 and synonomy, which is apparently not unusual in this author's 

 palseobotanical contributions. The definition given of this 

 Bohemian species, which is classed under the Gymnosperms as 

 " species incertse sedis," describes correctly the characters of 

 Sagenopteris Mantelli leaflets. The species is compared to Thinn- 

 feldia Lesquereuxiana, Heer;" but this Greenland fossil has quite 

 a different form, it shows a distinct midrib, and has no reticulate 

 venation : the connection is not obvious. 



Hosius and Von der Marck' have figured a leaflet of Sagenopteris 

 from the Neocomian Sandstone of the Teutoberger Wald under the 

 name S. Neooomiensis, Hos. and V. d. Marck ; this species closely 

 resembles S. Mantelli, and differs only in having a more distinct 

 midrib. 



A single leaflet from the Damuda series of India * also shows a 

 close resemblance to the Wealden form ; Feistmantel compares 

 it to Sagenopteris rhoifolia, Presl. It is exceedingly difficult to 

 arrive at any satisfactory results as to the limitation of the specific 

 forms of Sagenopteris. 



I have ventured to include under the "Wealden species the 

 Japanese fragments described by Tokoyama, as there are no 

 apparent differences which suggest specific distinction. 



A new species has been recorded from Bornholm under the name 

 S. Nathorsti, Barth. ; there is a resemblance worthy of note between 

 Bartholni's fig. 9, pi. v.' and the lowest, broadly-lobed leaflet on 

 the left-hand edge of Bunker's fig. 4, pi. ix. 



' Grymn. bohm. Kreid. pi ii. figs. 1-5. 



' Fl. fosa. Arct. toI. ti. pi. xliv. figs. 9-10. 



" PalsBontographioa, vol. xxvi. 1878, p. 210, pi. iUt. fig. 194. 



* Feistmantel, Foss. Fl. Gond. vol. iii. 1881, p. 114, pi. iliio. fig. 2. 



' Bot. Tid. Bot. For. Kjovenhavn, 1892. 



