PLATE XX 



i . Buccinum undatum Linne 



.. Colus gracilis Da Costa 



3. Neptunea stonei Pilsbry 



4. Littorina irrorata Say 



5. Nassa vibex Say 



6. Littorina litorea Linne 



7. Thais floridana Conrad 



8. Urosalpinx cinerea Say 



9. Cerithiopsis subulata Montagu 



10. Bittium alternatum Say 



11. Scalaria humphrysii Kiener 



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