may perhaps justify its preservation. ‘The venation, although 
in general very obscure, is very different in different species of 
the genus, as is the arrangement of the sori. 
PiaTE 20. Sterile and fertile fronds of Niphobolus angustatus, Spr.,—natural 
size. Fig. 1. Portion of a sterile frond, showing the venation. 2. Portion of a 
Jertile frond, showing sori and the stellated tomentum :—magnified. 
