MAN 



ORANG 

 GIBBON 



WESTERN 

 APES 



GORILLA 

 CHIMPANZEE 



EASTERN APES 



ANIMALS 



REPTILES 



INSECTS 

 SPIDERS 

 ETC 



CENTIPEDES 



r.RUSTACEANS 



TUNICATES 



M0LLU3C5 



COLONIAL PLAGELLATES 



INFUSORIANS 

 ETC 



PRIMITIVE UNICELLULARS 



Fig. I. — Tree illustrating the probable course of animal evolution. 



