！disguise的词根是guise，v. 假扮，伪装掩饰，隐瞒

Their streamlined bodies， the absence of hind legs， and the presence of a fluke and blowhole cannot disguise their affinities with land dwelling mammals.

它们的身体呈流线型，后肢完全消失，身体上长出了尾片和喷水孔，所有这些特征都无法掩饰它们与陆生哺乳动物之间的亲缘关系。