I06 THE EVOLUTION OF MAN. 



former class of characteristics, which alone have any phylo- 

 genetie significance, belong the primitive formation of the 

 vertebral column and the brain, the absence of the swim- 

 ming-bladder, of jaws, limbs, etc. 



It;i the animal system, the Round-mouths are usually 

 classed among Fishes ; but that this is quite incorrect is 

 apparent from the simple fact that, in all important and 

 prominent structural peculiarities, they are further removed 

 from the Fishes than the Fishes are from the Mammals and 

 from Man. 



