212 FORAMINIFERA 



Egeon Montfort, 1. c, p. 167 (genoholotype, Nautilus lenticularis 



FiCHTEL and Moll (part)). 

 Nummulina d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 295 (genotype, by 



designation, Camerina laevigata Brugiere). 

 Nummularia Sowerby, Min. Conch., vol. 6, 1826, p. 76 (genotype, by 



designation, Camerina laevigata Brugiere). 

 Amphistegina (part) Reuss, 1855. 



Test lenticular, planispiral, bilaterally symmetrical, involute; 

 wall perforate, calcareous, with a secondary skeleton and com- 

 plicated canal system; aperture simple at the base of the aper- 

 tural face, median. 



Carboniferous ( ?) to Oligocene. 



There are many subgeneric names for this and the following 

 not given here. 



Genus ASSILINA d'Orbigny, 1826 

 Plate 29, figure 7; plate 30, figure 5 



Genotype, by designation, Assilina discoidalis d'Orbigny 



Assilina d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 296 (as a subgenus of 



Nurtimulina) . 

 Nummulites (part) of authors. 



Test similar to Camerina but the test flattened, the chambers 

 usually not completely involute so that the earlier coils are not 

 covered, or with the wall very thin so that the earlier coils are 

 visible from the exterior. 



Eocene. 



Genus OPERCULINELLA Yabe, 1918 



Plate 29, figures 8, 9 ; plate 30, figure 4 

 Genoholotype, Atnphistegina cumingii W. B. Carpenter 



Operculinclla Yabe, Sci. Rep. Tohoku Imp. Univ., ser. 2, (Geol.), vol. 4, 



1918, p. 122. 

 Amphistegina W. B. Carpenter, 1859 (not d'Orbigny). 

 Nummulites H. B. Brady, 1884 (not Lamarck). 



Test lenticular and involute in the young, bilaterally sym- 

 metrical, in the adult with a broadly flaring complanate border ; 

 chambers simple; aperture at the base of the apertural face, 

 median. 



Late Tertiary and Recent. Indo-Pacific. 



