Phylum- porifera

                                       Phylum- porifera

                                                Characters.

—  Commonly known as “Sponges”

—  Multicellular, cellular level of organization

—  Solitary/ colonial, sessile

—  Shape vase-like cylindrical, tubular, many branched

—  Symmetry radial or none

—  Body wall- outer pinacoderm, middle mesenchyme, inner choanoderm

—  Cells loosely arranged, no definite layers

—  Body with many pores, canals & chambers- serving for water flow

—  Oscula present

—  Choanocytes or collar cells line special chambers

—  Skeleton of calcareous/ siliceous or spongin fibers

—  Digestion intracellular, respiratory, excretory organs absent, contractile vacuoles in some

—  Nervous system primitive

—  Hermaphrodite  but cross fertilization is rule

—  Asexual reproduction by budding/ gemmules

—  Sexual reproduction by ova & sperms

—  Regenerative power

—  Cleavage holoblastic

—  Development indirect by free swimming ciliated larva- Amphiblastula/ Parenchymula