Are all sponges part of phylum porifera and vice versa?
Yes, all of the sponges are part of Phylum Porifera, and everything within Phylum Porifera are sponges. There are three classes of sponges within the Phylum, Calcarea, Demospongiae and Hexactinellida. They are differentiated according to their structure and the spicules that make up the hard parts of the sponge.