REVISION OF THE GENUS PLASMOPORA

The foraminifer Tournayella Dain, 1953, formerly believed to be restricted to the Tournasian, is found in the upper part of the Frasnian, western Ural Mountain province. The Frasnianform is a subgenus of Tournayella and is here named T. (Eotournayella) jubra, n. sg., n. sp., monotypic. Eotournayella seems to be transitional from the ammodiscids to the tournayellids and to be ancestral to or to contain marks of characteristic structures in certain tournayellid stocks.—L.G. Henbest