506 



PTERIDOSPERMS, ETC. 



[CH. 



differences in the size and form of the meshes produced by the 

 anastomosing of the lateral veins are characters which cannot 



Fio. 340. 



B\ 



A. Glossopteris indica, Schimper. (j; nat. size.), 



B. Glossopteris angustifoUa, Brongniart. (Nat. size.) From Arber, 

 after Feistmantel. 



be recognised as having more than a secondary value, though, as 

 a matter of convenience, we employ them as aids to determina- 



