24 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 67 



Plate 4 



Fias. 1-3. Siphogenerina bifrons, var. striatula. X75. Specimen from the 

 Philippines. 

 4. Siphogenerina bifrons. X75. Broken, microspheric specimen. From 

 off Japan. 

 5, 6. Siphogenerina columellaris. (After Millett.) X 100. Figure 5, mi- 

 crospheric specimen, showing the internal structure; figure 6, megalo- 

 spheric form. Specimens from the Malay Archipelago. 

 7. Siphogenerina branneri. X75. Specimen from the type locality. 

 8,9. Siphogenerina virgula. (After Heron-Allen and Earland.) XIOQ. 

 Specimens from the Kerimba Archipelago, Southeast Africa. 



Plate 5 



Figs. 1, 2. Siphogenerina raphanus. X 75. Specimens from Porto Rico. 



3a, 6. Siphogenerina advena. X75. a,front view; 6, apertural view. Speci- 

 mens from Tortugas region, Gulf of Mexico. 

 4a, b. Siphogenerina mexicana. X75. a, front view; 6, side view. Speci- 

 mens from the Upper Eocene, Alazan Clay, Mexico. 

 5, 6. Siphogenerina striata, var. curta. X 75. Specimens from the Philip- 

 pines. 

 7,8. Siphogenerina raphanus, var. tropica. X75. Specimens from the 

 Philippines. 

 9-11. Siphogenerina columellaris. X75. Figures 9, 10, megalospheric forms 

 from the Philippines; figure 11, microspheric form from Samoa. 



Plate 6 



Figs. 1-4. Pavonina flabelliformis. (After Heron-Allen and Earland.) 



1. Young with the textularian stage just completed. X50. 



2. Early stage showing the semicircular chambers already 



developed. X50. 



3. Adult specimen with the chambers nearly annular. X50. 



4. Side view of specimen mounted in balsam, showing the 



arrangement of chambers in the development of the test. 

 X 70. (Specimens from the Kerimba Archipelago.) 

 Figs. 5, 6. Pavonina atlantica. 



Young specimens from the coast of Florida, showing the tex- 

 tularian young, and the wedge-shaped test instead of the 

 broadly curved chambers of the preceding species. The 

 ornamentation of the biserial portion is much coarser than 

 that of the later uniserial chambers. X 100. 

 Figs. 7-9. Pavonina mexicana, new species. 



7. Somewhat broken specimen, showing the trucate initial end, 



the proloculum and spiral chambers followed by a number 

 of textularian chambers. The uniserial chambers show no 

 tendency to become nearly annular. X50. 



8. A young specimen, showing the details of the early chambers. 



X 100. 



9. A partially developed specimen. X50. (Specimens from 



the Alazan Clays of Mexico.) 



o 



