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. [ MESH:A13.660 http://en.wikipedia.org/wiki/Nictitating_membrane ]
Synonyms: third eyelid palperbra tertia membrana nictitans nictitans
Term information
- Wikipedia:Nictitating_membrane
- null:Wikipedia:File:Chickenblinking.jpg
- SCTID:113326005
- NCIT:C77657
- MESH:D009541
- UMLS:C0028058 (ncithesaurus:Nictitating_Membrane)
pheno_slim
http://purl.obolibrary.org/obo/NCBITaxon_8570
http://purl.obolibrary.org/obo/NCBITaxon_376913
http://purl.obolibrary.org/obo/NCBITaxon_9709
http://purl.obolibrary.org/obo/NCBITaxon_8292
http://purl.obolibrary.org/obo/NCBITaxon_9632
http://purl.obolibrary.org/obo/NCBITaxon_261739
http://purl.obolibrary.org/obo/NCBITaxon_9835
http://purl.obolibrary.org/obo/NCBITaxon_9816
http://purl.obolibrary.org/obo/NCBITaxon_8782
The Calabar angwantibo (Arctocebus calabarensis, a lorisoid) is the only primate to have a functioning nictitating membrane[Wikipedia:Calabar_angwantibo]
Some reptiles, birds, and sharks have full nictitating membranes; in many mammals, a small, vestigial portion of the membrane remains in the corner of the eye. Some mammals, such as camels, polar bears, seals, and aardvarks, have full nictitating membranes. fully developed nictitating membranes can be found in lemurs and lorisoid primates.
in mice, the nictitating membrane is very small and composed of a very thin core of cartilage covered by loose connective tissue
In most primate species, a plica semilunaris is present, although fully developed nictitating membranes can be found in lemurs and lorisoid primates[Wikipedia:Nictitating_membrane]