Porifera

Porifera include the sponges . these are most primitive of multicellular animals.they are sessile and are fixed to some submerged object.The Plorifera belongs to Kingdom animalia. Most of members of this phylum are marine few are fresh water inhabitants. They maybe solitary or colonial. They have Cellular grade of body organisation shape is mostly cylindrical what are the shapes are also found. Body maybe radially symmetrical aur asymmetrical .They are diploblastic animals having two germ layers outer layer is called the derma and inner layer is called gastral layer.inbetween two layers there is  gelatinousmesogloea.it contains several amoeboid sales. Body has numerous pores called ostia for water entry and there is a large pore called osculum at the apex . coelom is absent but there maybe a cavity called spongocoel.water circulatory system is a unique features in the members of this phylum .endoskeleton consists of spicules which maybe calcareous made up of calcium carbonate  or silicious made up of silica. in some forms the Skeleton is made up of spongin fibres .spongin in a type of protein ingestion  is holozoic .digestion is intracellular .nervous system and circulatory system or absent. Both asexual and sexual reproduction occurs .asexual reproduction occurs by budding,gemmule formation and by regeneration .sexual reproduction involves fusion of gametes . fertilization is internal.Life cycle has free swimming larvae called amphiblastula or parenchymula.