ORDER II 



FORAMINIFERA 



31 



Subfamily (!. Polymorphininae Brady. 



Test composed of chambers arranged spirally or irregidarly about the long axis ; 

 aperture usually radiate. 



Polymorphina d'Orb. (Fig. 17, B). Segments irregularly helicoid, or 

 arranged biserially, more or less enveloping one another and variable in shape. 

 Terminal aperture round. Trias to Recent. 



Dimnrphina d'Orb. (Fig. 17, C). Early chambers irregularly or triserially 

 arranged, later ones following in rectilinear fashion. Cretaceous to Recent. 



Subfamily D. Uvigerininae Cushmaii. 



I'est composed of chambers arranged triserially about the long axis ; aperture 

 usually simple, with a definite neck and a phialine lip. 



Uvigerina d'Orb. (Fig. 17, E). Segments dissimilar, disposed in triple 

 series, and spirally wound like a gastropod shell. Eocene to Recent. 



Subfamily E. Eamulininae Brady. 



Test composed of chambers with long tubulariform tubes. 



Bamulina Rupert Jones. Test branching, consisting of rounded chambers 

 joined by stolon-like' tubes. Recent, and possibly also represented in the 

 Cretaceous. 



Family 7. Globigerinidae Carpenter. 



Test free, calcareous, perforated by coarse tubules ; monothalamous or poly- 

 thalamous ; chambers globular, either irregularly disposed or imperfectly spiral. 



Of the two principal genera belonging to this family, Orbulina d'Orb. (Fig. 

 18, A) is unilocular, and Globigerina d'Orb. (Fig. 18, 6') is multilocular. The 

 individual chambers 

 usually open into a 

 common central 

 canal. In both 

 genera the test is 

 often covered with 

 extremely delicate 

 calcareous spines, 

 which, however, are 

 very easily broken 

 off, and are never 

 preserved intact in 

 the fossil state. 

 Both these genera 



are excessively abundant in existing oceans (Globigerina doze) ; they occur 

 sparingly in the Trias and throughout the Mesozoic, first becoming important 

 during the late Tertiary. 



Sphaeroidina d'Orb. (Fig. 18, B). Characters few, so coiled as to form a 

 nearly globular test ; aperture with a valvular lip. Cretaceous to Recent. 



Fig. is. 



A, OrhuUna universa Lam. Pliocene ; Sienna, Italy. B, Sphaeroidina 

 ausfriaca d'Orb. Miocene Tegel ; Baden, near Vienna. C, Glohlijerina con- 

 glomerata Schwager. Pliocene ; Kar Nikobar Island, a, Inferior surface ; 

 '/, Superior surface ; c, Portion of periphery ; il, Transverse section enlarged. 



