10 



BOOK OF SPECIES. 



inside, whitish within, and greener towards the 

 margin ; the callus around the perforation oval ; 

 smallish. Excessively common. 



F. viRiDULA. Ovate-oblong, rather convex, 

 greenish, radiated with small white ribs, and an- 

 nulated by concentric striae, which form longi- 

 tudinally compressed tuberculations at their junc- 

 tion with the ribs; perforation oblong, inclined, 

 girded with a dark line; inside white; margin 

 crenulated ; small. 



F. HiANTULA. Oblong-elliptic, convexly de- 

 pressed, with the extremities elevated and arched ; 

 striae slender; perforation large and lengthened; 

 margin entire, above lilac-red, beneath whitish ; 

 small. There is a black variety, smallish. 



