PHYLUM AND CLASS PORIFERA 



117 



also amoeboid zooids similar to the amoeboid wandering- cells of 

 Sponges. 



But, while the Porifera are clearly Metazoa, and not Protozoa, 

 there is some room for difference of opinion as regards their 

 relationships to the Ccelenterata, with which great type they are 

 sometimes amalgamated. The reasons for and against such an 

 arrangement will be discussed in considering the general relation- 

 the Coelenterata. 



