_:b662818214 "Heterochronous homology that is produced by a retention in adults of a species of traits previously seen only in juveniles." . _:b662818214 . _:b662818214 . _:b662818214 . _:b662818214 . _:b662818214 . _:b662818214 . _:b662818214 "ISBN:978-0674639416" . _:b662818214 .