Amarjit
Last Activity: 7 Years ago
Sponges are members of phylum porifera meaning pore bearing. Spongs have a two layered body outer ectoderm known as pinacoderm and inner endoderm known as choanoderm and between these 2 layers a gel like structure mesenchyma is found. Their body contains many small opening called as ostia(analogous to mouth) and a single large opening called osculum(analogous to anus) and a central cavity called paragastric cavity or spongocoel.this cavity is lined by choanocytes(collar cells). Sponges are sessile and found at botton of ocean.