412 



THE EVOLUTION OF THE METAZOA 



-\ • r^-v. 



o^"* "^^ 



/' Pterygot 



Myriopoda 

 CheUcerata 



Tard/grada 

 Onychophora 

 » Protracheata 



OUGOMERIA 



Echiuroidea '\ 



H/rud/nea 

 CUtellata 



OUgochaeta 



Myzostom/dea 

 Polychaeta 



A MERIA 

 (Nemertino/dea) 



Fig. 56. Genealogical tree of the phylum: Polymeria. 



"Articulata," and they must be therefore clearly separated 

 from the latter. 



Contrary to the situation which we have found in the geo- 

 logically much older Ameria, we see that it is quite easy to 

 identify the two main lines of the evolution of the Polymeria 

 which have been used for a long time already as high taxons. 

 We will consider them as subphyla and use the names Annelida 

 and Arthropoda. It is quite easy to classify all the classes of the 

 Polymeria into one of these two subphyla. Beklemischew, on 

 the other hand, distinguished here five subphyla, i.e. Annelida, 



