Genus Ormoceras Stokes, 1840

Type species

Ormoceras bayfieldi Stokes, 1840 from Niibi, Estonia; Adila Formation, Pirgu Regional Stage, late Katian; subsequent designation by Bassler (1915).

Diagnosis

Medium-sized straight shells, circular or nearly so in cross section; siphuncle subcentral; segments almost globular; septal necks short cyrtochoanitic; endosiphuncular canal system moderately complex to simple, few radial canals. (Adopted from Teichert 1964a.)