Demosponge
Xestospongia sp. ( Order Haplosclerida )
The Horn siliceous sponges ( Demospongiae, gr: Folk sponges) form a class from the tribe of sponges ( Porifera ). With about 5,000 extant species in 600 genera, including three freshwater species, belong to this taxon at about 85 % of all extant species of sponges.
Structure of the endoskeleton
The skeleton contains the protein spongin and spicules ( spicules ) which consist of silicon dioxide. This type of spicules are also called Kieselspicula. Also known are some species whose skeletons consist either only of spongin or spicules only. By the spongin spicules are held together. If no spicules are present, the skeleton is formed by strongly intertwined Spongin. The Horn siliceous sponges are the only group of sponges, which form Spongin.
Bath sponges
For some species such as Hippospongia equina (horse sponge) and Spongia officinalis ( Common Bath Sponge ) from the subclass Ceractinomorpha and order Dictyoceratida be gained bath sponges (natural sponges). Today, however, most of the sponges is produced artificially.
System
The horn silica sponges are divided into three subclasses, and following orders:
- Subclass Homoscleromorpha Bergquist, 1978 Homosclerophorida Dendy, 1905
- Astrophorida Sollas, 1888
- Boury - Esnault & Chondrosida Lopès, 1985
- Hadromerida Topsent, 1894 Spheciospongia vesparium
- Agelasida Verrill, 1907
- Dendroceratida Minchin, 1900
- Dictyoceratida Minchin, 1900
- Halichondrida Gray, 1867
- Halisarcida Bergquist, 1996
- Haplosclerida Topsent, 1928
- Poecilosclerida Topsent, 1928
- Verongida Bergquist, 1978
- Verticillitida Termier & Termier, 1977
Chondrosia reniformis ( Chondrosida )
Spongia officinalis ( Dictyoceratida )
Spirastrella cunctatrix ( Hadromerida )
Phakellia sp. ( Halichondrida )
Petrosia ficiformis ( Haplosclerida )
Oscarella lobularis ( Homosclerophorida )
Phorbas tenacior ( Poecilosclerida )
Aplysina aerophoba ( Verongida )