This protome is very similar to the four that decorate the couch displayed in the adjacent Roman Imperial Gallery. The lion's head, however, is more rounded in shape and the glass eyes are better preserved and more realistic.
Christie's, New York. 1999. Antiquities. December 9, 1999. lot 409, pp. 104-5.
Picón, Carlos A. 2007. Art of the Classical World in the Metropolitan Museum of Art: Greece, Cyprus, Etruria, Rome p. 493, New York: The Metropolitan Museum of Art.