TPIE EVOLUTION OF MAN 



quite a thin thread of cartilage. It looks as if the 

 backbone had gradually melted away like a piece 

 of sugar in coffee. The spinal cord is no longer 

 surrounded by solid bone, it extends through 

 the body as a string of nerves, just as it does 

 among worms or insects. And nothing indicates 

 that typical characteristic which divides verte- 

 brates absolutely from all other animals, but the 

 position of this nerve string above the cartilagin- 

 ous thread and above the digestive tract, while 

 in all other animals the great nerve string is al- 

 ways located below the digestive tract. The back- 

 bone is here called merely the "chorda," and we 

 are here evidently at the point where the verte- 

 brates dissolve into invertebrates. 



And what does it matter? If man is disguised 

 in a lamprey or an Amphioxus, then we may as 

 well look for him entirely outside of the verte- 

 brates. One species of lamprey, which bore their 

 way into the bodies of other fish and live as para- 

 sites upon them, were still mistaken for worms 

 by Linnaeus himself. And the discoverer of Am- 

 phioxus thought that he had found a snail, which 

 it indeed resembles far more than a fish when we 

 dig it up from its hiding place in wet sand and 

 see its transparent and lancet-like little body. 



Any way, it makes no difference theoretically, 



no 



