Term Name:	nictitating membrane
Synonyms:	haw, membrana nictitans, nictitans, palperbra tertia, third eyelid
Definition:	A fold of the mucous membrane of the conjunctiva in many animals. At rest, it is hidden in the medial canthus. It can extend to cover part or all of the cornea to help clean the cornea.
Ontology:	Uberon Ontology [UBERON:0010207]