Calcareous sponge is a class of the Phylum Porifera. The species of Calcarea varies from radial symmetrical vase shaped body types to colonies made up of a reticulum of thin tubes or irregular massive forms. Calcareous sponges are generally characterized by their endoskeleton made up of spicules, they are sedentary filter feeders, and lack any real tissues. Calcareous sponges are most commonly found in shallow tropical waters. Generally, Calcarea are small sponges. The different shapes of calcareous sponges are relatively simple, either purse, vase, pear or cylinder-shaped. And the skeleton has a either a mesh or honeycomb structure. Unlike most other sponges, calcareous sponges lack hollow canals, which makes the sponge stronger.