Operculum papillare

The operculum papillare is the iris found in the eyes of elasmobranchs (skates, sharks and rays).{{Cite journal |last=Voronina |first=E. P. |date=2010-11-01 |title=On morphology and taxonomy of scophthalmids |url=https://doi.org/10.1134/S0032945210090018 |journal=Journal of Ichthyology |language=en |volume=50 |issue=9 |pages=695–703 |doi=10.1134/S0032945210090018 |bibcode=2010JIch...50..695V |issn=1555-6425|url-access=subscription }} It can undergo pupillary light reflex to such an extent that the eye is essentially shut off. It is sometimes called the golden iris because of the shine it sometimes causes.