Egg-and-arrow motif from the book A Handbook of Ornament by Franz Sales Meyer.
An egg list is an ornament motif often sculpted and carved in wood, stone, plasterwork consisting of an egg-shaped object alternated with an element in the form of an arrow or anchor. Owner list decorations in the Ionian chapter's artwork have been found in ancient Greek architecture of the Erechtheion.
This motif is common in the classic architecture of Europe from the Renaissance. Eggplant decoration on a chapel.
wiki
