Demosponges (Demospongiae)

Demosponges are the sponges of the class Demospongiae, the largest class of sponges, whose skeletons are made of spongin fibres, siliceous spicules or both. They include the barrel sponges of Caribbean reefs and the carnivorous deep-sea sponges that trap small animals on hooked spicules instead of filtering particles from the water. Glass sponges, whose skeletons are six-rayed silica spicules, are a separate class and have their own group.