Porifera: Aggregate of different cell types - no body layers; no nervous/digestive/circulatory systems; Pores and channels for circulation of water, oxygen, nutrients and to remove waste; no mouth or anus; silica or calcium carbonate based spicules for support; sessile with no body symmetry
Cnidaria: Radially symmetrical; single entrance to body cavity for circulation of respiratory gases and nutrients; cnidocysts/nematocysts for disabling prey; mobile (jellyfish) or sessile (sea anemones or polyp stages); calcium carbonate skeleton secreted by corals
Platyhelminthes: Soft bodied, unsegmented worms; no internal body cavity and no specialized circulatory or respiratory systems; flattened body shapes to allow for exchange of material by diffusion; bilaterally symmetrical; can be non-parasitic or parasitic (tapeworm)
Annelida: Soft bodies, with segments separated by internal septa; movement by peristalsis (contraction and relaxation of muscles that propagates along the worms body); bodies covered by a cuticle made of flexible collagen;
