Framework 63 



fold would run without interruption along the back to the 

 end of the tail, and on the under side would extend forward 

 as long as the cross-section of the body remained an elon- 

 gated oval, like this. 



But at the point where the cross-section changed, as it is 

 supposed to have done in some of the earlier fishes and still 

 does in the sharks, to triangular in the forward part of the 

 body, the lower fin-fold split up into parts and followed 

 along the angles, like this. 



Once these hypotheses are accepted, the rest is easy. The 

 fin-fold, originally continuous, disappeared in spots, and the 

 fragments of it which remained became the dorsal, caudal, 

 anal, ventral, and pectoral fins. 



Anyone who objects that it is preposterous to build a 

 theory on the evidence of a penholder coated with wax will 

 be referred to two of science's favorite sources of informa- 

 tion about the past: fossils and the biogenetic law. For the 

 remains of the very early fishes do suggest that something 

 like this happened. And our infant trout, and other fishes of 

 today, do come into the world bearing along their back a 

 continuous fin-fold, which extends around their tail and 

 along their under side as far as the ventj and parts of this 

 fin-fold do disappear, and the remaining fragments do be- 

 come the dorsal, caudal, and anal fins. Interpreted by the 

 biogenetic law, this corroborates the fossil evidence that the 

 remote ancestors of the trout did once wear a continuous 

 fin-fold throughout life, and that only through the processes 



