Phylum Porifera

Phylum Porifera: The Sponges

• Sponges are the simplest animals
• Radially symmetrical
• Acoelomate
• Body resembles a perforated sac.

• Has inner cavity called sponpocoel
• Has large opening called osculum
• Lining body are cells flagellated cells called choanocytes
  • These cells beat to produce a flow of H₂0 into the sponge through pores in through the body wall, and out through the osculum.
• Body wall is composed of many elements
  • Mesohyl - gelatenous material
  • Amoebocytes
    • Motile cells which perform many functions
    • Capture, digest and transport food
    • Create tough structural fibers of the body wall called spicules.