_:b663962945 . _:b663962945 "ISBN:978-0674639416" . _:b663962945 . _:b663962945 "Heterochronous homology that is produced by a retention in adults of a species of traits previously seen only in juveniles." . _:b663962945 . _:b663962945 . _:b663962945 . _:b663962945 . _:b663962945 .