576 CYCADOPHYTAN FRONDS [CH. 



or occasionally pinnatisect lamina were widely distributed in 

 Jurassic and Lower Cretaceous strata and persisted to the Upper 

 Cretaceous series in Japan. This form of frond is recorded from 

 England, Scotland, North America, Greenland, Spitzbergen 1 , 

 Siberia, Russia, Afghanistan 2 , Japan 3 , Graham Land, and else- 

 where. Reference has already been made to a petrified specimen 

 of N. orientalis described by Dr Stopes from Japan 4 . 



Specimens described by Salf eld 5 from the Corallian of Germany 

 as Taeniopteris sp. may be N. orientalis ; Bartholin's N. polymorpha 

 from Bornholm, Velenovsky's Lower Cretaceous N. bohemica and 

 Yokoyama's N. ozvana from Japan are other examples of fronds 

 which may be identical with N. orientalis 6 . 



Nilssonia tenuicaulis (Phillips). 



This Jurassic species, while agreeing generally in habit with 

 N. compta, is characterised by the narrow and numerous linear 

 segments with a more acuminate apex. The fronds reached a 

 length of more than 20 cm. 7 Leckenby's name Pterophyllum 

 medianum 3 was given to a specimen from the Yorkshire coast and 

 now in the Sedgwick Museum, Cambridge, which, with Ptero- 

 phyllum angustifolium, is clearly identical with Cycadites tenui- 

 caulis Phillips. The specific name mediana frequently used 9 

 for this type should be given up in favour of the older term 

 tenuicaulis. A species of similar habit is described but not 

 figured by Krasser 10 as N. Sturii from the Lunz beds. N. tenui- 

 caulis is fairly common in the Middle Jurassic beds near Scar- 

 borough and is recorded from the Kimmeridgian of Scotland under 

 the name N. mediana (fig. 614, C) 11 . 



Nilssonia princeps (Oldham and Morris). 



Oldham and Morris speak of Pterophyllum princeps 12 as one 

 of the commonest plants in the Rajmahal beds in India. The 



I Nathorst (97) PI. i. fig. 18. 2 Seward (12) p. 30. 

 3 Yokoyama (89) B. ; Nathorst (90) A. 4 Stopes (10 2 ). 



6 Salfield (09) B. PI. m. figs. 57. 6 For references, see Seward (12) p. 31. 



7 Phillips (29) A. p. 148, PL vn. fig. 19. 



8 Leckenby (64) A. p. 77; Seward (00) B. p. 227, PI. iv. figs. 14. 



9 Seward (00) B. p. 227. 10 Krasser (09) p. 120. 



II Seward (II 2 ) p. 697. 



12 Oldham and Morris (63) B. p. 23, Pis. x. xm. ; Feistmantel (77) PL XLVII. 



