FAMILY 25. CAMERINIDAE 213 



Genus OPERCULINA d'Orbigny, 1826 

 Plate 29, figure 10; plate 30, figure 6 



Genotype, by designation, Oj^e^'culina complanata d'Orbigny 



Overculina d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 281. 



Nautilus (part) of authors. 



LenticulUes (part) Defrance, 1822. 



Amphistegina (part) d'Orbigny, 1826. 



Nonionina (part) Williamson, 1852. 



Nutnmulina (part) Parker and Jones, 1865. 



Test bilaterally symmetrical, planispiral, complanate, usually 

 all the coils visible from the exterior, earlier coils sometimes 

 involute; wall calcareous, perforate, smooth or ornamented with 

 bosses; aperture single, at the base of the apertural face, median. 



Lower Cretaceous to Recent. 



Genus HETEROSTEGINA d'Orbigny, 1826 

 Plate 29, figures 11, 12; plate 30, figure 7 



Genotype, by designation, Heterostegina depressa d'Orbigny 

 Heterostegina d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 305. 



Test similar to Operculina, the early chambers simple, later 

 ones divided into chamberlets; aperture consisting of a row of 

 rounded openings on the narrow apertural face. 



Eocene to Recent. 



Genus SPIROCLYPEUS H. Douville, 1905 



Plate 29, figure 14 



Genotype, by designation, Spiroclypeus orbitoideus H. Douville 



Spiroclypeus H. Douville, Bull. Soc. Geol. France, ser. 4, vol. 4, 1905, 

 p. 458. 



Test somewhat similar to Heterostegina but more accelerated, 

 the curved chambers divided into chamberlets beginning almost 

 immediately after the proloculum, lateral chambers and pillars 

 developed at each side of the test. 



Miocene of the East Indies. 



