Phylum Mollusca: Soft and Plentiful. All squid species belong to the broad Animalia Kingdom. As the name implies, all animals belong to this kingdom. Members of this kingdom are multicellular and use other living things to supply their nourishment.Within that kingdom, squid belong to the narrower Mollusca phylum.Their phylum includes between 50,000 and 200,000 species, according to the University of California Museum of Paleontology. These soft-bodied creatures include slugs, scallops and clams.hylum Mollusca: Soft and Plentiful. All squid species belong to the broad Animalia Kingdom. As the name implies, all animals belong to this kingdom. Members of this kingdom are multicellular and use other living things to supply their nourishment.