an Entity references as follows:
Cyrtocycloceras is a genus of orthocerids from the Middle Silurian of Europe included in the Paraphragmitidae. The shell, or conch, of Cyrtocycloceras is a moderately expanding annulated exogastric cyrtocone, with curvature like that of a rocking chair rocker. Annulations, encircling ribs, are close spaced and transverse and the surface is transversely striated.