208 FORAMINIFERA 



Genus POLYSTOMELLINA Yabe and Hanzawa, 1923 

 Plate 27, figure 11; plate 28, figure 6 



Genoholotype, Polystomella (Polystomelliyia) discorbinoides Yabe and 



Hanzawa 



Polystomellina Yabe and Hanzawa, Jap. Journ. Geol. Geog., vol. 2, 1923, 

 p. 99. 



Test similar to Elphidium in general structure but trochoid, 

 planoconvex, ventral side flattened, dorsal side convex. 

 Tertiary and Recent. 



Genus FAUJASINA d'Orbigny, 1839 

 Plate 27, figure 12; plate 28, figure 7 



Genoholotype, Faujasina carinata d'Orbigny 



Faujusina d'Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. Cuba, 1839, 

 "Foraminiferes'', p. 109. 



Test similar to Elphidium but trochoid, planoconvex, dorsal 

 side flattened, ventral side convex. 



Cretaceous to Recent. 



This small family includes Bradyina and Crihrospira, two 

 Palaeozoic genera which seem allied to Nonion and Elphidium, 

 but the fuller study of their complete development may change 

 this view as their early stages are possibly not planispiral. The 

 trochoid forms, Nonionella, with simple sutures, and Polystomel- 

 lifia and Faujasina have apparently developed from the plani- 

 spiral forms. The structure in some of the larger species of 

 Elphidium becomes complex. 



FAMILY 25. CAMERINIDAE 



Test generally planispiral and bilaterally symmetrical, in the 

 early stages involute, in the later stages often evolute; wall 

 calcareous, perforate ; in the higher forms with a secondary 

 skeleton and complex canal system. 



KEY TO THE GENERA 



I. Test with a long undivided second chamber Archaediscus. 



II. Test with numerous chambers, not divided into chamberlets. 



