FORAMINIFERA 



501 



Test planispirally coiled or becoming straight, or single-chambered; 

 fossil and recent Family 24 Lagenidae 



Genus Lagena Walker and Jacob (Fig. 212, a) 



Test biserial or elongate spiral; fossil and recent 



Family 25 Polymorphinidae 



Genus Polymorphina d'Orbigny 



Test not vitreous; aperture not radiating 



Test planispiral, occasionally trochoid, then usually with processes 

 along the suture lines, septa single, no canal system; fossil and 

 recent Family 26 Nonionidae 



Fig. 212. a, Lagena striata, X50 (Rhumbler); b, Elphidium strigilata, 

 X40 (Kiihn); c, Operculina ammonoides, X50 (Kuhn); d, Pavonina 

 flabelliformis, X30 (Brady); e, Hantkenina alabamensis, X40 (Cushman); 

 f, Bolivina -punctata, X100 (Kuhn); g, Rotalia beccarii, X40 (Kiihn); h, 

 Asterigerina carinata, X30 (d'Orbigny from Kiihn). 



Genus Elphidium Montfort (Figs. 5; 208, C; 212, b) 



(Polystomella Lamarck) 



Test planispiral, at least in young, generally lenticular, septa double, 



canal system in higher forms; fossil and recent 



Family 27 Camerinidae 



Genus Operculina d'Orbigny (Fig. 212, c) 



Test generally biserial in at least microspheric form, aperture usually 



large, without teeth; fossil and recent 



Family 28 Heterohelicidae 



