5. Multicellular body consisting of outer ectoderm and inner endoderm with an intermediate layer of mesenchyme therefore, diploblastic animals.
6. The interior space of the body is either hollow or permeated by numerous canals lined with choanocytes . The interior space of sponge body is called spongocoel.
7. Characteristic skeleton consisting of either fine flexible spongin fibres siliceous spicules or calcareous spicules.
8. Mouth absent , digestion intracellular; excretory and respiratory organs absent.