LO BOOK OF SPECIES. 
inside, whitish within, and greener towards the 
margin ; the callus around the perforation oval; 
smallish. Excessively common. 
F. virnipuLA. Ovate-oblong, rather convex, 
greenish, radiated with small white ribs, and an- 
nulated by concentric strie, 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. nrantuLa. Oblong-elliptic, convexly de- 
pressed, with the extremities elevated and arched; 
strie slender; perforation large and lengthened ; 
margin entire, above lilac-red, beneath whitish ; 
small. There is a black variety, smallish. 
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