240 CLASSIFICATION AND ORGANIZATION OF ANIMALS 



Animal 

 Kingdom 



Phylum 



Protozoa . Protozoa 



Single- 



celled 

 animals 



Parazoa 



Without 

 gut cavity 

 or enteron 



Metazoa . . 

 Many- 

 celled 

 animals 



Enterocoela 



Without 

 ccElome, dip- 

 loblastic or 

 triploblastic 



Mesozoa 

 Porifera 



Diploblastic 

 Ccelenterata 



Triploblastic 

 Platyhelminlhes 



Coelome problematical 

 body non-metameric 

 N emathelminth.es 

 Trochelminthes 

 Molluscoida 



Enterozoa . 

 With 

 gut cav- 

 ity or 

 enteron 



Ccelomocaela .... Coelome recognizable, 

 Coelome pres- ^ body non-metameric 

 ent or prob- Mollusca 



lematical, Echinodermata 



triploblastic Coelome recognizable 



body metameric 

 Anmdata 

 Arthropoda 

 Chordata 



Plant Kingdom 



Subdivided in a manner comparable with that shown for the Animal Kingdom 



i 



1 



Fig. 117. — Classification of the principal groups of animals 

 {r:f Fig. 118 and list of phyla on opposite page.) 



