Abstract.- "Cyrtocerattites arduennensis", one of the stratigraphically oldest ammonoids and type
 species of the ainbiguously defined genus Anetoceras, was first described from the Eitel Mountains.
 lt has been misiterpreted several. times and is here re-described based oli the holotype and
 additional material from the type area.  Anetoceras arduennense (STEININGER, 1853) has a crioconical
 conch with whorls almost touching the preceding volution.  The revision of the subfamily Aneto-
 ceratinae leads to the result that only five genera (Metabactrites,Borivites, Ivoites gen. nov.as a
 replacement name for Teneroceras, Anetoceras, and Erbenoceras) can bc regarded valid, wlich
 probably represent a phyletic series.