Demospongiae
Demosponges are the largest group of sponges with skeletons made of ibers of the protein spongin, the mineral silica, or both. They have a very different body shape than glass sponges and include 90% of all sponge species. Most of these sponges are marine dwellers but some live in fresh water. They demospongiae are an ancient category as they have fossils since fossils appearing in the Precambrian period.
Demospongia like the other sponges lack a nervous system and specialized tissue since it is a loose connection of cells. Since it has no tissue it is unable to form a brain to connect to a nervous system.
Demospongia like the other sponges lack a nervous system and specialized tissue since it is a loose connection of cells. Since it has no tissue it is unable to form a brain to connect to a nervous system.