PLATE XVIII 



1. Crepidula fornicata Linne 



2. Crepidula plana Say 



3. Sinum perspectivum Say 



4. Crepidula convexa Say 



5. Columbella avara Say 



6. Nassa trivittata Say 



7. Melampus lir^atus Say 



8. Terebra c va Say 

 9. 



10. Terebra ^ jcata Say 



11. Polinices duplicata Say 



12. Polinices heros Say 



.-■a* 



