PLATE 



la, lb. Spondylus americanus Hermann. Florida Keys. 3.5 

 ing spines, p. 3S. 



2. Ostrea permollls Sowerby. Sanibel, Florida. 1.5 



3. Ostrea frons Linne. Sanibel, Florida. 45 mm. p 



4. Ostrea virglnica Gmelin. Virginia. 8 inches, p 



5. Pllcatula gibbosa Lamarck. Sanibel, Florida. 1 



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



7. Periploma angiilifera Philippi. Charleston, South Carolina. 



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



Beach valves, lack- 



31. 



38. 



18 mm. p. 40. 



