The organs which were functional in the ancestors but non-functional and reduced in the descendants are called vestigial organs.
Presence of vestigial organs is the most convincing evidence in favor of organic evolution and also supports the concept of disuse proposed by Lamarack.
In man, there are nearly 180 different types of vestigial organs.
Hence, Weidersheim described human being a "Moving Museum of Antiquities" or a "Moving Museum of vestigial organs".
Eg: Vermiform appendix , coccyx , plica semilunaris , auricular muscles that move the pinna , hair on the body , mammary glands in males etc.