*pterotic*

a. [ Gr. &unr_; wing + &unr_;, &unr_;, ear. ] (Anat.) Of or pertaining to, or designating, a bone between the prootic and epiotic in the dorsal and outer part of the periotic capsule of many fishes. -- n. The pterotic bone. [ 1913 Webster ]

☞ The pterotic bone is so called because fancied in some cases to resemble in form a bird's wing [ 1913 Webster ]