174 PTERIDOSPERMS [CH. XXXI 



specimens do not convey the impression of naked seeds and in 

 some examples there are indications of an investing envelope, 

 though this may be the result of tearing of the testa. Nathorst 

 regards the Spitzbergen seeds as probably specifically identical 

 with a specimen described by Schmalhausen 1 from Carboniferous 

 rocks in the Urals as Rhabdocarpus orientalis Eich., a species which 

 agrees closely with Lagenospermum nitidulum as described by 

 Heer 2 (under the name Carpolithes nitidulus) and Nathorst 3 from 

 Spitzbergen. It is also possible that Kidston's Rhabdocarpus 

 elongatus*, from the Lanarkshire coal-field and elsewhere, recently 

 transferred by Arber 5 to Platyspermum, is an example of the 

 same species. The chief interest of Lagenospermum lies in the 

 fact, assuming Nathorst's correlation of the seeds with Adiantites 

 bellidulus Heer to be correct, that it is a typical radiospermic 

 seed, while Wardia, borne on foliage of the same general type, 

 is an equally typical platyspermic seed. 



1 Schmalhausen (83) PL iv. figs. 1315. 



2 Heer (77) A. PL v. pp. 2325. 



3 Nathorst (14) p. 30, PL xv. fig. 59. 



4 Kidston (86) p. 70, PL in. fig. 6. 



6 Arber, E. A. N. (14) p. 96, PL vi. fig. 12. 



