actinoceras (of Brown)

[Gr. ἀκτίς ( aktis ), gen it. ἀκτῖνος ( aktinos a ray, and κέρας ( keras ) = a horn. Lit Ray-horned, i.e. having the "horns" or feelers radiated.] Zool. The second sub-genus of the mol luscous genus Orthoceras (q.v.). In 1851 Woodward estimated the known species at six. They are all fo il, and extend from the Silurian to the Carboniferous rocks.