For a gold ring of nearly identical form, said to be from Pozzuoli and formerly in the Castellani collection, see no. 91 in F.H. Marshall, Catalogue of the Finger Rings, Greek, Etruscan & Roman in the Departments of Antiquities, British Museum. For the motif of the gem, compare the example cut on the convex back of a scaraboid, no. 18 in C. Wagner and J. Boardman, A Collection of Classical and Eastern Intaglios, Rings and Cameos.