PLATE 



la, lb. 



2. 

 3. 

 4. 

 5. 

 6. 

 7. 

 8. 



Spondylus americanus Hermann. Florida Keys. 3, 



ing spines, p. 32. 

 Ostrea permollis Sowerby. Sanibel, Florida. 1. 

 Ostrea frons Linne. Sanibel, Florida. 45 mm. 

 Ostrea virginica Gmelin. Virginia. 8 inches. 



Beach valves, lack- 



p. 31. 



1 inch. p. 32. 



Plicatula gibbosa Lamarck. Sanibel, Florida. 



Macoma tenta Say. Bermuda. 15 mm. p. 59. 



Periploma angxilifera Phillppi. Charleston, South Carolina. 



Mesodesma arctata Conrad. New England. 1.5 inches, p. 66. 



18 mm. p. 40. 



