(a) Resemblance with Metazoa 1. Both are sedentary in habit. 2. Both are diploblastic and acoelomates. 3. Both reproduce asexually and form colonies. 4. Both sponges and coelenterates show the presence of same nucleic acids and amino acids. 5. Parenchymula larva of sponges resembles planula larva of coelenterates. 6. Spongocoel in sponges opening out through osculum can be compared with gastrovascular cavity of coelenterates opening out through mouth. (b) Differences with Metazoa 1. In sponges, cells are less specialised and less independent than those of metazoa. 2. Sponges do not have anterior end though osculum serves physiologically as controlling region. 3. Primary openings are not present as osculum in sponges. 4. Body surface is perforated by inhalent pores or ostia extend by water channels, a unique feature of sponges only. 5. Tissue formation is restricted to the formation of epithelial lining on the surface. There are no organs as found in higher animals. 6. Sponges lack true mouth. Osculum does not correspond with the mouth of coelenterates. 7. Stinging cells are found in coelenterates are lacking in sponges. 8. Nervous system is lacking in sponges.