Large circular test, centrally umbonate and narrowed at the periphery. Annular chambers subdivided into chamberlets.
Genera of family “Nummulitidae”
Involute to evolute test, centrally thickened, chambers divided into chamberlets.
Globular test, lenticular or discoidal,planispirally enrolled.
Test planispiral and evolute, flattened, numerous narrow chambers in many rapidly expanding whorls, sutures strongly curved back at the periphery.
Smooth exterior, undivided chambers. External similarities in shape to N. venosus but is distinguished by the latter by the possession of trabeculae. Thick lenticular central part and flat final chambers in large individuals.
Planispirally, semi-involute to evolute coiled test, incomplete division of chambers into chamberlets.
Test planispiral, semi-involute to evolute, complete division of chambers into chamberlets.