BRAZIL NIJT TREE IN CEYLON. 



429 



upper surface is sometimes feebly sulcate. Only its apical point 

 projects through the opercular opening, and owing to the 

 inward expansion of the latter the operculum remains within 



-r^- 



, -,f— p.—Ai...,, 



Fig 1. 



^?>, 



^K 



' i^^ 



the pyxidium when the columella shrivels. The accompany- 

 ing figure shows the operculum with part of the columella 

 attached. 



Fig. 2. 



From the fact that the operculum remains within the 

 pyxidium, the Peradeniya tree should be referred to B. nobilis ; 



