Vestigial or rudimentary organs are the useless ruminants of structure of organs which might have been large and functional in the ancestors. e.g.. Vermiform appendix, nictitating membrane, vestigial tail coccyx, etc., in man. Splint bones are vestigial organs in horse. The wings in flightless bird kiwi are vestigial Whale and python have vestiges of bones of hind limb and pelvic girdle embedded in the flash abdomen.