Bull. U. S. B. F., 1909. 
Plate XXII. 
Organisms constituting the food of mussels. Protozoa. (All figures except 7 after Calkins.) 
1. Exuvisella marina Cienkowsky. X 780. 
2. Glenodinium compressa Calkins. X 822. 
3. Ceratium fusus Ehrenberg. X 315, 
4. Distephanus speculum Stohr. X 960. 
5. Exuvigella lima Ehrenberg. X 780. 
6. Peridinium divergens Ehrenberg. X 636. 
7. Prorocentrum micans Ehrenberg. X 375- 
8. Tintinnopsis davidoffi Daday. X 354. 
9. Tintinnopsis beroidea Stein. X 900. 
