Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.
直到最近才发现的化石，显然是介于陆地哺乳动物和鲸类之间的过渡物种。
2
Other features, however, show experts that Pakicetus is a transitional form between a group of extinct flesh-eating mammals, the mesonychids, and cetaceans.
然而，专家认为巴基鲸是已经灭绝的食肉哺乳动物中爪类和鲸类之间的过渡物种。
3
Poverty levels omit the transitional dynamics between levels.