Darwin also noted, in On the Origin of Species, that a vestigial structure could be useless for its primary function, but still retain secondary anatomical roles: "An organ serving for two purposes, may become rudimentary or utterly aborted for one, even the more important purpose, and remain perfectly efficient for the other.... n organ may become rudimentary for its proper purpose, and be used for a distinct object."
Darwin tamén sinalou en On the Origin of Species que unha esturutra vestixial podía ser inútil para a súa función primaria, pero aínda manter papeis anatómicos secundarios: "Un órgano que serve para dous propósitos, pode facerse rudimentario ou abortado completamente para un deles, mesmo para o propósito máis importante, e permanecer perfectamente eficiente para o outro....