Phylum Porifera (Sponges)

large opening at one end of the body, through which water flows out of the songespicules

• surround the osculum
• made of calcium carbonate,
• provide protection and body support for the sponge

• asexually by budding
• suxually

• Line the central cavity and the channels leading into it
• each has a flagellum which beats, helping to maintain flow of water through the cell.
• Engulf and digest food particles carried into the sponge by the flow of water

roam between the epithelial and collar cells, digesting and distributing nutrients throughout the sponge, producing reproductive cells, and secreting spicules.

flexible proteinaceous spicules

• spongin
• spicules made of silica sillica