Pore bearer
• Least evolutionarily advanced group of animal kingdom
• Sessile adult
• Lack of symmetry
• Anatomy
– Lack of organ and tissue
• Each cell dependence
• Lack of a digestive or respiratory system, nervous system,
muscles and a true mouth
– 2 layers + intermediate mesophyll
• Outer---pinacocyte
• Middle—mesophyl—skeleton of calvareous or siliceous spicules by amoebocyte
• Inner—flagellated cell----collar cell or choanocytes
• Choanocytes ingest food