THE INVERTEBRATE PHYLA 



109 



Mommolia 



Reptilia- 

 Amphibia - 



Insecta 



Apterygogenea 



Diplopoda 

 Chilopoda 

 Protracheata 

 Arthroppdq 



Arachnoidea 



Xiphosura 



Pantopoda 



Crustacea 



Kamptozoa 

 Nematomorpha 



Nematodes 

 Acanthocephala 

 Priapuloidea 



Sporozoa 

 Rhizopoda 



Flagellata 

 Fig. 38. Hadzi's classification of the Invertebrate Phyla. 



often a differentiation of the cytoplasm in a manner that can be 

 compared with the ectoderm, mesoderm and endoderm of the 

 metazoa. Hadzi thinks that such a ciliate gave rise to a form 

 resembling an acoelous turbellarian and that the Turbellaria are 

 the most primitive of the Metazoa. The Turbellaria then gave 

 rise to the Anthozoa, as has been mentioned on p. 95. 



The coelom of the metazoa is traced back to the mesohyal 



