Animal Kingdom~Sponges Phylum~Porifera/Parazoa/Sponges *All sponges are aquatic,mostly marine,fresh water. *These are primitive multicellular animals and have cellular level of organisation. Sponges have a water transport or canal system. Water enters through minute pores (ostia) in the body wall into a central cavity, spongocoel, from where it goes out through the osculum. *Sponges are sessile organisms and remain attached to an underwater objects,called Substratum. *Choanocytes or collar cells line the spongocoel and the canals. *No distinct tissue or organ. *Symmetry Radial or no symmetry. *Body wall with outer pinacoderm(dermal epithelium),inner choanoderm(gastral epithelium) and gelatinous non-cellular mesechyme in between. *Choanoderm is mainly made of choanocytes.The cells(choanocytes) are characteristics of porifers. * The body is supported by a skeleton made up of spicules or protein spongin fibres. *Sponges are the only m