It doesn't have one.
phylum porifera are sponges.
The simplest kind of invertebrates would be sea sponges. They are part of the phylum Porifera and are the only animals that do not have a nervous system at all.
The nervous system. Cnidarians have a neural net, but porifera do not.
phylum porifera
All invertebrates except Porifera possess nervous system .
The phylum Porifera contains two subphlya. They are the Symplasma and Cellularia.
Members of the phylum porifera are commonly called as sponges.
The phylum Porifera is sponges.
phylum porifera
Porifera are sponges.
Porifera is a phylum, not a kingdom, but I assume you mean the phylum in the kingdom Animalia. According to wikipedia, there are about 5000 different species in Porifera.
Individuals in the phylum porifera are asymmetrical.