Classification
Class Calcarea: Include sponges with the body forms ascon, leucon, and sycon. These organisms have spicules, which are composed of calcium carbonate, and are all marine. Their spicules also have three or four rays. The Leucosolenia sponge (shown below) fits into this class.
Class Hexactinellida: Include sponges with the body forms leucon and sycon, these sponges are usually sup or vase shaped. The organisms of this class have spicules composed of silica, the spicules are also fused into an intricate lattice. Their spicules are also six-rayed. The Euplectella sponge (shown below) fits into this class.
Class Demospongiae: Include sponges with the body form leucon. The organisms of this class have siliceous spicules or spongin, sometimes both. Their spicules are four-rayed. Only class that includes freshwater sponges. The Cliona sponge (shown below) fits into this class.
Class Hexactinellida: Include sponges with the body forms leucon and sycon, these sponges are usually sup or vase shaped. The organisms of this class have spicules composed of silica, the spicules are also fused into an intricate lattice. Their spicules are also six-rayed. The Euplectella sponge (shown below) fits into this class.
Class Demospongiae: Include sponges with the body form leucon. The organisms of this class have siliceous spicules or spongin, sometimes both. Their spicules are four-rayed. Only class that includes freshwater sponges. The Cliona sponge (shown below) fits into this class.