I? 



and Rhipidistia. No one could fail to see, even from only fossil 

 remains, how closely they are related. Because somewhat earlier 

 fossils of the Rhipidistia than of Coelacanths are known, most 

 scientists today hold the view that the Rhipidistia came first and 

 that Coelacanths developed from them. Because this view was 

 expressed by one or two leading workers, even without any 

 really positive evidence, it is commonly held even today. If it were 

 true, however, since all those forms lived under the same con- 

 ditions, it is almost incredible that there should be no sign of 

 transitional types. But in fact, there are the Rhipidistia, and there 

 are the Coelacanths, and nothing in between. It is at least as likely 



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Fig. I . — A Rhipidistian fish, Eusthenopteron, that is believed to be the ancestor 

 of land animals. About 12 inches in length. 



that both of these types came from some as yet unknown common 

 ancestral form, and that form would be ancestral to man as well. 

 I have a 'hunch' that one day the remains of something like this 

 will be discovered in earlier strata. 



Be that as it may, let us examine the history of these two impor- 

 tant main lines of fishy evolution. Both lived in swamps. Their 

 fins indicate that both were able to leave the water and flop about 

 on land, either from necessity or desire. There is good evidence 

 that the Rhipidistia gave rise to amphibia and hence to all other 

 land vertebrates, including man, while the original stock, the 

 Rhipidistian fishes themselves, all died out very long ago. The 

 recent appearance of the Coelacanth has taught us a lesson, and 

 we had better be careful and say rather that all the available 

 evidence indicates that the Rhipidistia became extinct long ages 

 ago. In other words, while they themselves were not strong enough 

 to survive profound changes, by some accident they gave rise to 

 creatures that found a new way of life on the land. It was in one 

 sense their own weakness that led to the survival of and ultimate 



