EXPLANATION OF PLATES. 
Plate XXIX. 
Fig. I. Glochidium of slop bucket, Anodonta corpulenta, on caudal fin of a young skipjack, Porno- 
lobus chrysochloris. 
Fig. 2. Young paper shell, Lampsilis IcBvissima, on gill of sheepshead, Aplodinotus grunniens (side 
view) in an early stage of development. 
Fig. 3. Postero- or antero-ventral view of young Icevissima of about the same development as 
figure 2. 
Fig. 4-5. Another stage of development of Icevissima, figure 4 representing side and figure 5 dor- 
sal views. 
Fig. 6-7. Side and dorsal aspects of Icevissima upon reaching what is considered its greatest 
development as a parasite. 
Plate XXX. 
Fig. 8. Postero-dorsal view of young deer-toe, Plagiola donaciformis, on gill of sheepshead, Aplo- 
dinoius grunniens. 
Fig. 9. Side view of donaciformis on gills, the metamorphosis about completed. 
Fig. 10. Portion of gill of Aplodinotus with young donaciformis in situ. 
Fig. II. Glochidium of niggerhead, Q. ebena, on gill filament of skipjack, Pomolobus chryoschloris, 
taken August 13. 
Fig. 12. Dorsal and ventral views of ebena of same relative age as figure 11. 
Plate XXXI. 
Fig. 13. Quadrula ebena presumed to have about completed its metamorphosis; a specimen taken 
September 23, 1912. 
Fig. 14. Distal third of gill filament with glochidia of ebena in position. 
Fig. 15. Glochidium of Quadrula metanevra on gill filament of sunfish, Lepomis pallidus. 
Fig. 16. Glochidium of Quadrula plicata on gill filament of sauger, Stizostedion canadense. 
Fig. 17. Glochidium of Pleurobema cesopa on gill filament of the sauger {S. canadense). 
Fig. 18. Young ebena on gill filament, showing shifted position. 
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