Plate 15 



Figures 1-3. Spirolina acicularis (Batsch). Fig. 1. (After Batsch.) Figs. 2, 3, 

 Tortugas, Fla. X 100. 

 4, 5. Spirolina arietinus (Batsch). Fig. 4. (After Batsch.) Fig 5, 



Tortugas, Fla. X 60. 

 6-8. Peneroplis discoideus Flint. Fig. 6, Montego Bay, Jamaica. X 

 25. Fig. 7, Bermuda. X 25. Fig. 8, Tortugas, Fla. X 25. 

 9, 10. Borelis pidchra (d'Orbigny). Fig. 9 a, 6. (After d'Orbignj'.) a, 

 side view; h, apertural view. Fig. 10 a, b, Nassau Harbor, 

 Bahamas. X 30. a, side view; b, apertural view. 

 11, 12. Monalysidium poliium Chapman (?). X 100. Tortugas, Fla. 

 72 



