Genus Dysidea Johnston, 1842

Type species. Spongia fragilis Montagu, 1814: 78 (by subsequent designation).

Diagnosis. Thickly encrusting, massive or branching growth form, often with a marked conulose surface and a distinct net or web-like surface pattern, interconnecting conules. Species with heavy intra-mesohyl detritus are not conulose. Skeleton consists of a relatively regular, usually rectangular arrangement of concentrically laminated primary and secondary fibres, with primary fibres orientated perpendicular to the surface, but may also be less regular, with divaricating primary fibres and secondary fibres supported by fine auxiliaries. All fibres are axially or fully cored, although this may be in the form of scattered fragments rather than a dense core. Primary fibres are also pithed though this is usually obscured by the coring material. The sponge is soft and compressible, sometimes made fragile by large amounts of sand etc. incorporated into the sponge tissue. There is only light collagen deposition in the mesohyl, and the sponges are histologically simple, with few secretory cell types present (modified from Cook & Bergquist, 2002).