Sponges; a body made of cells and many species; sessile; filter\suspension feeder; digestion happens inside cells; osculum; hermaphrodite; simplest of all animals; no true tissues, but do have specialized cells.
Have true tissues; include jellyfish, anemones, corals, hydra; two forms medusa (free swimming) or polyp (sessile); have cnidocytes (stinging cells); gastrovascular cavity.
Comb jellies; rows of fused cilia, relatives of Cnidaria.
-Divided into 3 classes.
-First to show bilateral symmetry.
Contain free living, small flat worms, examples: planaria, many species of marine worms; have a simple brain and nerves that branch out throughout the body; have complex gastovasacular cavity; show great powers of regeneration.