11. The eyes are large and circular, with nictitating membranes ( protective third eyelids ). 12. Instead the eye is lubricated by the nictitating membrane, a third eyelid that moves horizontally. 13. The eyes lack a nictitating membrane. 14. There is no nictitating membrane and the cornea is continuous with the skin surrounding the eyes. 15. The "'nictitating membrane "'of a Masked Lapwing as it closes. 16. The nictitating membrane also covers the eye and acts as a contact lens in many aquatic birds. 17. In addition, glands on the nictitating membrane secrete a salty lubricant that keeps the eye clean. 18. The Calabar angwantibo is the only primate to have a functioning nictitating membrane ( third eyelid ). 19. The irises of the eyes are golden to brown, and the transparent nictitating membrane is pale blue. 20. The millisecond before contact with wood a thickened nictitating membrane closes, protecting the eye from flying debris.
