236 FORAMINIFERA 



Subfamily 6. Plectofrondicularinae 



Test in the microspheric form planispiral in the early stages, 

 later biserial and then uniserial or in the higher forms starting 

 as uniserial tests ; ornamentation bilaterally symmetrical ; aper- 

 ture rounded or elliptical, terminal. 



EXPLANATION OF PLATE 34 

 Heterohelicidae, Hantkeninidae 



Fig. 



1. Heterohelix americana (Ehrenberg). (Adapted from Ehrenberg). a, 



exterior; 6, section. 



2. Pavonina flabelliformis d'Orbigny. a, side view, (After Heron-Allen 



and Earland) ; b, section of P. mexicana Cushman. 



8. Giimbelina globulosa (Ehrenberg). 



4. Pseudotextularia varians Rzehak. a, microspheric; b, megalospheric. 



5. Piano globutina acervulinoides (Egger). 



6. Bolivhioides rhomboidalis (Cushman). 



7. Bolivinita eleyi Cushman. a, front view; b, side view. 



8. Bolivinella folium (Parker and Jones). 



9. Spiroplectoides rosida (Ehrenberg). (Adapted from Ehrenberg). a, 



exterior; b, section of another specimen. 



10. Spiroplectinata annectenn (Parker and Jones). (After Parker and 



Jones). 



11. Plectofrondicularia mexicana (Cushman). a, front view; b, apertural 



view; c, section. 



12. Amjihiinorphina haueria7ia Neugehoven. (After Neugebor en), a, front 



view; b, section of compressed portion; c, section of inflated portion. 



13. Nodomorphina compressiuscula (Neugeboren). (After Neugeboren). 



14. Eoiivigerina gracilis Cushman. a, front view; b, side view; c, aper- 



tural view. 



15. Pseudo7ivigerina crifstata (Marsson). a, front view; b, section. 



16. Siphogenerinoides plu7rimeri (Cushman). 



17. Nodogenerina bradyi Cushman. 



18. Hantkenina alabamensis Cushman. a, side view; b, apertural view. 



19. Mimosina hystrix Millett. (Adapted from Millett). a, side view; b, 



apei'tural view. 



20. Triynosiyia millefti Cushman. (After Millett). a, front view; 6, 



apertural view. 



