These reliefs once decorated a dining couch. They would have been attached to the two ends of the fulcrum (headrest), with the head of Cupid in a roundel at the lower end and the duck’s head, with a glass insert for the eye, forming the curving upper end.
Breck, Joseph. 1920. "Pre-Gothic Ivories in the Pierpont Morgan Collection." The Metropolitan Museum of Art Bulletin, 15(1): p. 12.