CREATION BY EVOLUTION 



of the Devonian coal forests. Man also owes to these 

 Devonian fishes his very ability to breathe. 



Man has, moreover, inherited from these amazingly ancient 

 animals each and every one of his twenty-eight skull bones, 

 as well as every other bone of his entire skeleton. But the 

 earlier types possessed many more bones in the skull than 

 man does. The late Professor Williston, of the University 

 of Chicago, showed that as we pass from earlier to later 

 vertebrates reduction in the number of the skull elements 

 is the rule, although there is here and there an exception 

 due to the fragmentation of one of the remaining elements. 



Fishes, in common with all other vertebrates, have, on 

 each side of the head, the three semicircular canals which 

 act like spirit levels and assist the animal in maintaining 

 its equilibrium. Below the semicircular canals is a sack 

 supplied with nerves. A part of this sack corresponds to the 

 true organ of hearing in man. The cavity of the human 

 ear (behind the drum membrane) is represented in fishes 

 by the cavity of the gill chamber. Fishes have no drum 

 membrane, which first appears in the amphibians, but its 

 place is occupied in the fishes by the bony shell or operculum 

 covering the outer side of the gill chamber. When the air- 

 breathing fishes were changed into amphibians the opercular 

 series disappeared, leaving only a notch at the outer upper 

 corner of the skull, upon which was stretched the drum 

 membrane of the ear. 



Thus, by the time amphibians originated from some air- 

 breathing lobe-finned fishes, all the fundamental problems 

 in the production of the ground plan of the human organiza- 

 tion had been solved, and it is literally true that the oldest 

 amphibians were on the whole much nearer to man than 

 they were to the oldest known ostracoderms. Nevertheless, 

 a host of improvements in the entire mechanism were still to 

 be worked out, and to these striking advances we now turn 



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