BULL. 
U.S. B. F., 1917-18. PLATE XXVI. 
Upper: Paper-shell, Anodonta suborbiculata (Say). (See p. .35) A dis gytee 
Lower pair: Spectacle-case, Margaritana monodonta (Say), from Mississippi River. (See p. .35) 
The three small shells in upper left-hand corner of plate are examples of Spheride, not fresh-water mussels. 
