THE EVOLUTION OF MAN 



ians are very closely related to the vertebrates. 

 It is true that on the one side they are buried 

 deeply in the worm type far below Amphioxus. 

 But on the other side they have the chorda, the 

 first trace of a genuine backbone. But since some 

 of them show this chorda only in the embryo 

 stage, it seems evident that their ancestors had 

 a still stronger hold on this rudiment, and were 

 therefore still closer to the vertebrates than most 

 of the present ascidians, which have evidently 

 somewhat degenerated in this respect. So that 

 Amphioxus and ascidians would be two branches 

 of the common archetype which would, first of 

 all, have developed the chorda. This archetype 

 in order to produce the present-day ascidians 

 must have been in all other respects unmistakably 

 a wormlike animal. In short,jwej2just jpok for 

 other traces of man in worms. 



The term "worm" applies in the system to an 

 enormous mass of different animals. There are 

 hundreds of groups of fundamentally different 

 worms. Some of them are of a higher order, 

 with blood and sense organs and a genuine cen- 

 tral nerve system. We would have to derive 

 vertebrates most likely from them. If so, we 

 should imagine a worm, which would not pos- 

 sess a chorda like Amphioxus or the lamprey, but 



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