74 BULLETIN 161, UNITED STATES NATIONAL MUSEUM 



Plate 16 



FiGtTRES 1-3. Operculina granulosa (Leymerie) (?). X 27. Fig. 2a, Side view; 

 b, peripheral view. Guam Anchorage, Ladrone Islands. 

 4-9. Helerostegina depressa d'Orbigny. Fig. 4, X 40. Figs. 5-9, X 27. 

 a, a, a, a, a, a, Side views; b, b, b, b, b, b, peripheral views. 

 Fig. 4, Albatross H3891. Figs. 5, 8, Makemo Lagoon, Paumotu 

 Islands. Fig. 6, Guam Anchorage, Ladrone Islands. Fig. 7, 

 Albatross H3849. Fig. 9, Vavau Anchorage, Tonga Islands. 



Plate 17 



Figures 1-5. Helerostegina curva Moebius. X 27. Figs. 3a, 4a, 5a, Side views; 

 6, b, b, peripheral views. Showing different stages in develop- 

 ment. Figs. 1-3, Albatross H3875. Figs. 3, 4, Albatross 

 H3814. Fig. 5, Albatross H3849. 

 6a, b. Helerostegina suborbicularis d'Orbigny. X 27. a, Side view, b, 

 peripheral view. Albatross H3885. 



Plate 18 



Figures la, 5. Cycloclypeus guembelianus H. B. Brady. X 27. a, Side view; 

 b, peripheral view. Albatross H3876. 

 2-6. Operculinella venosa (Fichtel and Moll). X 27. Fig. 6a, Side 

 view; b, peripheral view. Levuka, Fiji. 



Plate 19 



Figures 1-3. Peneroplis planatus (Fichtel and Moll). X 40. 40-50 fathoms 

 off Fiji. 

 4, 5. Spirolina arietina (Batsch). X 40. Fig. 5o, Side view; 6, aper- 



tural view. 30-40 fathoms off Fiji. 

 6, 7. Spirolina acicularis (Batsch). X 50. Mokaujar Anchorage, 



Fiji. 

 8, 9. Monalysidium politum Chapman. Fig. 8, X 50. Fig. 9, X 40. 

 Fig. 8, Guam Anchorage, Ladrone Islands. Fig. 9, Makemo 

 Lagoon, Paumotu Islands. 

 10. Alveolinella quoyi (d'Orbigny). X 15. Mokaujar Anchorage, 

 Fiji. 

 11, 12. Marginopora vertebralis Quoy and Gaimard. X 8. Mokaujar 

 Anchorage, Fiji. 



