188 ] The Classification of Lower Organisms 



Family 7. Orbulinida Schultze 1854. Family Globigerinida Carpenter 1862. 

 A few genera with the chambers mostly few, subglobular, clustered rather than ar- 

 ranged in a definite pattern. Orbulina. Globigerina, abundant, pelagic in all oceans, 

 the shells abundant in the ooze on the bottom. Pennsylvanian, doubtful; Jurassic, rare; 

 Cretaceous to the present, common. 



Family 8. Pegidiida [Pegidiidae] Heron-Allen and Earland 1928. A few genera 

 much like the Orbulinida but with thinner walls. Pegidia, etc. Oligocene to the 

 present. 



Family 9. Heterohelicida [Heterohelicidae] Cushman 1927. A numerous group, 

 the shells screw-like, biseriate, uniseriate, sheath-like or fan-like, the walls often with 

 exterior ornamentation; paralleling the Nodosarina, but without the radiate orifices. 

 Heterohelix, Sagrina, Eouvigerina, Pavonina, Plectojrondicidaria, Bolivina, Mucron- 

 ina. Common, Jurassic to the present. 



Family 10. Buliminida Jones 1876. Family Uvellina Ehrenberg (1839), not 

 based on a generic name. Family Buliminina Lankester (1885). Shells mostly high 

 spirals, screw-like, often with spines or other external ornamentation, the orifices 

 various, commonly comma-shaped. Turrilina, Bulimina, Virgulina, etc. Triassic to 

 the present. 



Family 11. Cassidulinida [Cassidulinidae] d'Orbigny (1839). A small group with 

 high-spiralled shells and comma-shaped orifices, evidently derived from the forego- 

 ing family. Cassidulina, etc. Eocene to the present. 



Family 12 Uvigerinida [Uvigerinidae] Galloway and Wissler, 1927. Further vari- 

 ants from Heterohelicida, the high-spiralled shells with chambers in three rows at 

 first, varying to biseriate and uniseriate. Uvigerina, Siphonogenerina, etc. Jurassic 

 to the present, common since the Miocene. 



Family 13. Pleurostomellida [Pleurostomellidae] Reuss 1860. An additional 

 rather small family of the same general character as the few preceding. Pleurosto- 

 mella, Nodosarella, Daucina, Ellipsoidina, etc. Cretaceous to the present, commonest 

 in upper Cretaceous and Eocene. 



Order 5. Nummulitinidea Lankester in Enc. Brit. ed. 9, 19: 848 (1885). 



Rhizopoda with large specialized shells, the walls hyaline, perforate, generally 

 thickened and traversed by channels and thrown into internal ridges which subdivide 

 the chambers. 



Family 1. Fusulinida [Fusulinidae] Moller 1878. Carboniferous fossils, the 

 chambers short and broad, numerous, in a planispiral coil, forming bodies which are 

 usually fusiform or globular. Orobias, Fusidina, Triticina, Verbeekina, etc. 



Family 2. Nummulitida [Nummulitidae] Reuss 1861. Family Camerinidae 

 Meek and Hayden 1865. Family Nummulinidae Brady (1881). Family Nummuli- 

 tina Lankester ( 1885). Family Nummulitaceae Lister. Mostly disk-shaped, planispiral, 

 the walls not highly specialized. Camerina Bruguiere 1792 {Nxunrnulites Lamarck 

 1801), Operculina, Heterostegina, etc. Jurassic to the present, most abundant in the 

 Eocene. 



Family 3. Orbitoidida [Orbitoididae] Schubert 1920. Similar to the foregoing, 

 the numerous chambers divided into numerous chamberlcts. A considerable group of 

 Mcsozoic and Ccnozoic fossils. Orbitoides, Cyclosiphon, etc. 



Family 4. Cycloclypeina Lankester (1885). Family Cycloclypeidae Galloway 

 (1933). Similar to the preceding. A number of Mcsozoic and Ccnozoic genera, most 

 numerous in the Eocene. Asterocydina. The only living species is Cycloclypeiis Car- 

 penteri Brady. 



