THE EVOLUTION OF MAN 



evolution of worms. I speak of sponges, higher 

 polypi and jelly-fish. These would form a definite 

 circle, and all higher forms above the skin-and- 

 stomach animals of the lowest class would be 

 traceable to one common origin, viz., this skin- 

 and-stomach animal itself. But now we recall 

 that law which so frequently reproduces the por- 

 trait of ancestors in the formation of the embryo. 

 If the circumstantial evidence is to be conclusive, 

 then the embryonic development of all animals 

 from the jelly-fish to the vertebrate ought to re- 

 produce such a portrait, representing the double 

 cylinder of skin and stomach with one single 

 orifice, a prototype of Pemmatodiscus, or Hydra. 

 Here again all resistance is useless. It is unde- 

 niable that such embryonic marks reappear in all 

 nooks and corners of the higher classes of ani- 

 mals. Itjs that gfcge wh fct* %r wi ha * Hp< ?Jg- 

 nated as Gastrula. 



It is hardly possible to find anything more 

 different than a coral, a higher worm, a sea- 

 urchin, a lobster, or a snail in the adult stage. 

 Nevertheless, all of them show such characteris- 

 tic skin-and-stomach larvae. They occur in many 

 of the animals named and become more frequent 

 with our progress in the direction of the lower 

 formation, where we find them in the shape of a 



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