235 



EXPLANATION OF PLATE 18 

 Figure Page 



116. Anatina lineata (Say) 89 



117. Anatina plicatella (Lamarck) 90 



118. Corbula contracta Say 90 



119. Corbnla caribaea d'Orbigny 91 



120. Corbula krebsiana C. B. Adams 91 



121. Corbula swiftiana C. B. Adams 91 



122. Hiatella arctlca (Linne) 92 



