Bull. U. S. F. C. 1897. (To face page 377.) 
Plate II. 
FRESH-WATER MUSSEL, Margciritana margaritifera, SHOWING PEARL INCLUDED BETWEEN MANTLE AND SHELL, 
IN THE LOWER RIGHT-HAND CORNER. 
Specimen prepared by V. Fric, of Prague. From Botova River, Bohemia. 
