Assertion: eagle's eyelid | /r/Synonym | nictitating membrane
Facets:
Source sentences:
text: Besides the usual pair of eyelids, bald eagles have a see-through eyelid called a nictitating membrane.
text: For blinking, they also have an inner eyelid called a nictitating membrane.
text: Like cats, the birds have an inner eyelid called a nictitating membrane.