,30 BULLETIN 104, UNITED STATES NATIONAL MUSEUM 



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. 



This family evidently started very early and there are Carboniferous 

 forms which apparently are the earhest beginnings of the group, 

 although the family did not reach its greatest development until 

 the Eocene. During that geologic period very large species were 

 developed and were very abundant, especially in the Eastern Hemis- 

 phere. In America, Operculina and Heterostegina were large and 

 abundant during the Middle and Upper Eocene, but the very large 

 complex Nummulites evidently did not migrate to this region. In 

 the shallow waters of the Indo-Pacific there are still living many large 

 forms related to the Eocene ones but in the western Atlantic the family 

 is almost wanting, the only genus represented in the collections 

 studied being Heterostegina, and that is evidently very rare. 



Subfamily 1. Archaediscinae 



Test not broken up into chambers. 



Genus ARCHAEDISCUS H. B. Brady, 1873 



Archaediscus H. B. Brady, Ann. Mag. Nat. Hist., ser. 4, vol. 12, 1873, 

 p. 286. — CusHMAN, Special Publ. No. 1, Cushman Lab. Foram. Res., 1928, 

 p. 209. 



Genoholotype. — Archaediscus Icarreri H. B. Brady. 



Test lenticular, consisting of a proloculum and long undivided 

 second chamber, close coiled; wall thick, calcareous, finely perforate, 

 upper and lower surfaces thickened; aperture at the open end of the 

 chamber. 



Carboniferous. 



Subfamily 2. Camerininae 



Test with numerous chambers. 



Genus NUMMULOSTEGINA Schubert, 1907 



Nummulostegina Schubert, Verhandl. k. k. Geol. Reichs., 1907, p. 212. — 

 Cushman, Special Publ. No. 1, Cushman Lab. Foram. Res., 1928, p. 209. 



Genoholotype. — Nummulostegina velihitana Schubert. 

 Test lenticular, planispiral, bilaterally symmetrical, divided into 

 chambers, without complex secondary skeleton or canal system; 



