16 UNIVERSITY OF MISSOURI BULLETIN 



days after attachment, showing premature liberation of glochi- 

 dium. 



8. Cross-section of glochidium of Lampsilis recta 114 

 days after attachment, showing the young mussel leaving the 

 fish and the tissue of the cyst degenerating. 



9. Cross-section of glochidium of Symphynota complanata 

 1 hour after attachment. 



10. Cross-section of glochidium of Symphynota complanata 

 1 hour after attachment, showing mitoses and injured epithelial 

 cells around glochidium. 



1 1 . Cross-section of glochidium of Symphynota complanata 

 3 hours after attachment. 



12. Cross-section of glochidium of Symphynota complanata 

 6 hours after attachment, showing the cells of the larval mantle 

 taking up the fish's cells enclosed between valves of glochidium. 



13. Cross-section of glochidium of Symphynota complanata 

 6 hours after attachment, showing the glochidium completely 

 embedded. 



14. Cross-section of glochidium of Symphynota complanata 

 48 hours after attachment. 



