A: (FISH) A lobe fin of approximately 300 million years ago (essentially Eusthenopteron) B: (INTERMEDIATE) hypothetical C: (AMPHIBIAN) A primitive foot of some 200 million years ago. (Erypos)
The fin of the living coelacanth is believed to resemble the ancient type shown in the first drawing above, possessed in essential characteristics by the ancient fish Eusthenopteron of about 300 million years ago. This series of three drawings, based on the data and conclusions of several well-known scientists, shows the probable evolution of the amphibian foot, on the direct evolutionary line to all the great animals that walk the earth today. But long after the passably good foot C was evolved 200 million years ago, the coelacanths clung to their backward form, so that today the living fish has something of the out-moded appearance of one of the first horseless carriages on a four-lane highway.