Porifera
Proifera are characterized by the possession of a feeding system unique among animals. Porifera don't have mouths; instead they have tiny pores in their outer walls through which water is drawn. This is also how they respire.
Proifera are characterized by the possession of a feeding system unique among animals. Porifera don't have mouths; instead they have tiny pores in their outer walls through which water is drawn. This is also how they respire.
Calcareous sponges (Calcarea) are classified by their calcium carbonate spicules use for structural support. All sponges gain oxygen from water through diffusion. Water enters through their small pores called Ostia. Sponges use choanocytes to move the oxygen throughout their bodies because of a lack of blood and a circulatory system.