The class Homoscleromorpha is the most recent class identified. Their spicules are fused in large complicated patterns. They are composed of silica, the same chemical compound that makes up glass. Instead, they exist mainly in deep Arctic waters. Glass sponges are not found in coral reefs.

Generally, they are not as large or brightly colored as demosponges. Their skeletal structure is made up of large spicules of calcium carbonate. They can be found living on coral reefs in the shallow waters of tropical regions. Scientists have identified around 400 species of calcareous sponges. The common household sponge is a dried demosponge. They have varied skeletal structures which can be made up of spongin fibers, spicules of silica or calcium carbonate, or any combination of these. Demosponges can grow quite large, to over 2 meters in height. These include four main classes, glass sponges, calcareous sponges, demosponges, and homoscleromorpha.Īpproximately 90% of all sponge species are in this class.They are often brightly colored, unlike the dull glass and calcareous sponges. There are currently around 5,000 known sponge species.

Can sponges move